Next Steps in Invertebrate Welfare, Part 2: Possible Interventions

Summary

Whether in­ver­te­brates pos­sess the ca­pac­ity to have valenced ex­pe­riences is still un­cer­tain. On the as­sump­tion that in­ver­te­brate welfare is a rele­vant cause area, we ex­plore here differ­ent pos­si­bil­ities of as­sist­ing in­ver­te­brates, both those liv­ing in the wild and those un­der hu­man con­trol. When pos­si­ble, spe­cific in­ter­ven­tions to re­duce in­ver­te­brate suffer­ing are pre­sented. In other cases, I sug­gest which ques­tions should be fur­ther in­ves­ti­gated in or­der to bet­ter un­der­stand the prob­lem and to study fea­si­ble in­ter­ven­tion strate­gies.

Introduction

In­ver­te­brates are com­monly as­sumed to be in­ca­pable of ex­pe­rienc­ing pos­i­tive or nega­tive states. In a se­ries of pub­li­ca­tions by Re­think Pri­ori­ties, we have been ex­plor­ing sev­eral rele­vant ques­tions and sur­vey­ing the sci­en­tific ev­i­dence about this mat­ter. In this se­ries:

Sup­pose we are able de­ter­mine that there is an im­por­tant prob­a­bil­ity that in­ver­te­brates of cer­tain species are sen­tient and ex­pe­rience un­nec­es­sary suffer­ing. Is there any­thing we can do to help them? Since it is not even clear whether (some) in­ver­te­brates are con­scious, what we may or may not do on their be­half is a mat­ter of even greater un­cer­tainty. This topic is ad­dressed here, in the twelfth post of this se­ries.

Our pre­vi­ous posts can be seen as ad­dress­ing the epistemic ob­jec­tions against the view that in­ver­te­brates are con­scious (e.g. Bate­son, 1991; Eise­mann et al., 1984). Yet, be­yond this, some prac­ti­cal ob­jec­tions against con­sid­er­ing in­ver­te­brate welfare a worth­while cause have also been pressed. In par­tic­u­lar, (i) some claim that harm­ing in­ver­te­brates such as in­sects is in­evitable, hence, con­cern about their suffer­ing is im­prac­ti­ca­ble. Others, when think­ing in gen­eral about an­i­mals in na­ture, (ii) sug­gest that helping those in­di­vi­d­u­als is un­re­al­is­tic or that it might have nega­tive un­fore­seen con­se­quences (Horta, 2015).

Cer­tainly, it is im­pos­si­ble to live with­out caus­ing some harm. We’ve all ac­ci­den­tally kil­led a fly or stepped on ants. How­ever, that does not en­tail we should al­low un­nec­es­sary and pre­ventable suffer­ing. In ad­di­tion, it is prob­a­ble that these an­i­mals suffer harms not caused by hu­mans but mostly due to nat­u­ral events (see Horta, 2010; Ng, 1995)[1]. Fur­ther­more, as it will be dis­cussed be­low, the real force of the sec­ond prac­ti­cal ob­jec­tion con­sists in en­courag­ing us to in­ves­ti­gate fur­ther about pos­si­ble ways to help in­ver­te­brates in need.

I shall ex­plore here differ­ent pos­si­bil­ities to as­sist in­ver­te­brates, clearly dis­t­in­guish­ing be­tween helping those liv­ing in the wild, on the one hand, and those un­der hu­man con­trol, on the other. When pos­si­ble, spe­cific al­ter­na­tives to re­duce in­ver­te­brate suffer­ing are pre­sented. In other cases, I sug­gest some ques­tions that need to be in­ves­ti­gated in or­der to bet­ter un­der­stand the prob­lem and to study fea­si­ble in­ter­ven­tion strate­gies.

In­ver­te­brates liv­ing in the wild

Are nat­u­ral causes of suffer­ing tractable?

Let’s first con­sider the case of in­ver­te­brates liv­ing in the wild. If they were sen­tient, their suffer­ing would be pre­dom­i­nantly caused by nat­u­ral events. Some forms of helping an­i­mals such as honey bees and bum­ble bees are known and have been already car­ried out —al­though for other pur­poses, such as an in­ter­est in en­vi­ron­men­tal con­ser­va­tion. Th­ese in­ter­ven­tions in­clude pro­vid­ing ad­e­quate food, wa­ter, or sheltered place to rest for ex­hausted bees, as well as other first aid mea­sures (see e.g. here, here, and the story of Frostie, a bee in dis­tress)[2].

Th­ese ac­tions show that helping an in­ver­te­brate like an in­sect is not some­thing that can­not be done. But such a small-scale in­ter­ven­tion seems in­signifi­cant given the scale of the suffer­ing that in­ver­te­brates cope with —on the as­sump­tion that they are sen­tient. Fur­ther­more, one may ask what the con­se­quences of pro­mot­ing such forms of in­ter­ven­tion would be at a larger scale. For ex­am­ple, sup­pose we found a hu­mane way to re­duce the pop­u­la­tion of an in­ver­te­brate species that, as a rule, had a ter­rible qual­ity of life. As their pop­u­la­tion de­creased, that might cause an in­crease in the pop­u­la­tion of an­other species of in­di­vi­d­u­als who com­peted with them for re­sources. That may cause the net re­sult of our in­ter­ven­tion to be nega­tive.

In gen­eral, when we con­sider hy­po­thet­i­cal in­ter­ven­tions on a larger scale on be­half of in­ver­te­brates that are not un­der hu­man con­trol, the com­mon de­nom­i­na­tor is un­cer­tainty: cur­rently, we do not know how to help them. Even in the face of a spe­cific form of in­ter­ven­tion, im­por­tant epistemic difficul­ties arise. We know that com­plex in­ter­ac­tions take place in ecosys­tems. In­ver­te­brates play a key role in those pro­cesses—e.g. in­sects, see Schowalter et al., 2018; Scud­der, 2017–, and there prob­a­bly is an un­ex­plored re­la­tion­ship be­tween ecosys­tem in­tegrity and wild an­i­mal welfare. Given the above, di­rect in­ter­ven­tions to pro­mote in­ver­te­brate welfare can rather end up in­creas­ing to­tal suffer­ing in na­ture (Delon & Purves, 2018).

Nev­er­the­less, it should be noted that un­cer­tainty is not ex­clu­sive to this mat­ter. Con­ser­va­tion in­ter­ven­tions already strug­gle with ques­tions of this sort (see e.g., Keim, 2019). In ad­di­tion, as Rowe (2019) points out, efforts to re­duce global poverty risk spillover effects as well. In gen­eral, “any effort to im­pact the far-fu­ture might in­volve a high de­gree of clue­less­ness”, he adds. Thus, un­cer­tainty is not nec­es­sar­ily a de­ci­sive ar­gu­ment for dis­miss­ing a cause, nor for con­clud­ing that it is in­tractable. At least re­gard­ing an­i­mal suffer­ing in na­ture, hav­ing in­suffi­cient knowl­edge means that we should learn more so as to max­i­mize our chances of suc­cess­ful in­ter­ven­tion.

Hence, we need to in­ves­ti­gate and eval­u­ate differ­ent pos­si­ble ways of in­ter­ven­ing in na­ture, tak­ing into ac­count their di­rect pre­sent im­pact and in­di­rect fu­ture effects. In other words, we need to pro­mote sci­en­tific re­search that at least takes into con­sid­er­a­tion (i) the well-be­ing of in­di­vi­d­u­als, (ii) the re­la­tion­ship be­tween ecosys­tem in­tegrity and wild an­i­mal welfare, (ii) the im­pact of spe­cific in­ter­ven­tions on ecosys­tem dy­nam­ics, and (iv) the long term. Given the mag­ni­tude of the prob­lem, re­search into large-scale rather than small-scale forms of in­ter­ven­tion should be pri­ori­tized.

In­ver­te­brates that suffer from an­thro­pogenic causes

For the time be­ing, we are in a bet­ter po­si­tion to miti­gate the an­thro­pogenic harms that in­ver­te­brates face. At least as far as ter­res­trial in­ver­te­brates are con­cerned, we can hy­poth­e­size that one of their main sources of di­rect an­thro­pogenic harms is agri­cul­ture. In crop cul­ti­va­tion in­ver­te­brates like in­sects are prob­a­bly crushed by trac­tors and com­bines, their shelters are de­stroyed, and they are poi­soned with pes­ti­cides[3]. How­ever, we know very lit­tle about the scale of these prob­lems. As Fischer and Lamey (2018) point out, “a con­ser­va­tive es­ti­mate is well over 250 mil­lion in­sects per hectare, and some judge that it’s over a billion per hectare”.

Of all the an­thro­pogenic harms suffered by in­ver­te­brates in crops, per­haps the ones we know most about—or at least, the ones that ap­pear as some of the most tractable—are those caused by in­sect pop­u­la­tion con­trol meth­ods. In crop cul­ti­va­tion, the mas­sive use of chem­i­cal in­sec­ti­cides has been en­couraged in or­der to check the over­pop­u­la­tion of rapidly mul­ti­ply­ing in­sects, con­sid­ered “pests” (Carere & Mather, 2019).

In­sec­ti­cides prob­a­bly cause slow and painful deaths (Oven, 2018). We need to de­ter­mine whether this suffer­ing is avoid­able. Are there any other meth­ods to effec­tively con­trol in­sect pop­u­la­tions and which avoid the suffer­ing typ­i­cally caused by in­sec­ti­cides?[4] In gen­eral, in­sect pop­u­la­tion con­trol meth­ods can be clas­sified into the fol­low­ing ma­jor cat­e­gories: phys­i­cal con­trol, cul­tural con­trol, breed­ing and other ge­netic meth­ods, biolog­i­cal con­trol, and chem­i­cal con­trol (Hill, 1997; Mahr, 2007).

De­scribing the di­ver­sity of ex­ist­ing con­trol mechanisms goes be­yond the scope of this ar­ti­cle. Thus, in what fol­lows, we fo­cus on some tech­niques of phys­i­cal, cul­tural and chem­i­cal con­trol meth­ods which are likely to cause less suffer­ing than the use of com­mon in­sec­ti­cides or other ap­proaches, such as the in­tro­duc­tion of preda­tors, par­a­sitic in­sects, and in­sect pathogens (forms of biolog­i­cal con­trol). For a fur­ther de­scrip­tion of the lat­ter and a gen­eral overview of differ­ent con­trol meth­ods, see Flint & Dreis­tadt (1998), Hill (1997) and Mahr (2007). For a broader dis­cus­sion of this prob­lem see also To­masik (2017a, 2018, 2019).

  • Phys­i­cal con­trol: Th­ese are meth­ods that phys­i­cally keep in­sects from reach­ing the crops. Glasshouses—al­though im­ple­mented for cli­mate con­trol—are a good ex­am­ple of these mechanisms. Float­ing row cov­ers for hor­ti­cul­tural crops are also a phys­i­cal bar­rier that blocks in­sects’ ac­cess and re­duces their re­pro­duc­tion rates.

Traps, for their part, are a com­mon tech­nique that, un­for­tu­nately, causes a slow, and pos­si­bly painful, death. More­over, sticky traps pro­duce a sig­nifi­cant amount of by­catch, in­clud­ing lady­bugs, lacewings and even some ver­te­brates, like lizards and birds. As pre­vi­ously sug­gested, the nega­tive im­pact of these traps on the lives of wild an­i­mals can be re­duced by at­tach­ing a layer of ny­lon tulle mesh to the trap that limits by­catch (Sé­ta­mou et al., 2019). Since sticky traps are widely used in many agri­cul­tural set­tings and de­ployed in large num­bers, ap­ply­ing this mesh could re­duce the suffer­ing of a sig­nifi­cant num­ber of wild an­i­mals (both in­ver­te­brates and ver­te­brates).

Fur­ther­more, in the sce­nario that lar­vae do not have the ca­pac­ity to ex­pe­rience pain and plea­sure in a morally sig­nifi­cant way, there are spe­cific meth­ods that can trap and kill these ju­ve­niles be­fore they reach a stage of de­vel­op­ment in which they are con­scious. Ad­di­tion­ally, tar­get­ing lar­vae may check nascent in­sect pop­u­la­tions be­fore they scale, which might mean many fewer deaths than if the pop­u­la­tion is oth­er­wise not con­trol­led. In this sense, codling moth lar­vae, for in­stance, can be trapped un­der card­board bands wrapped around ap­ple trees; there­upon, the bands are re­moved and de­stroyed.

Other used meth­ods are fruit bags –i.e., putting bags over the fruits. The bags act as a phys­i­cal bar­rier that pre­vents in­sects from dam­ag­ing the fruit. In­ert kaolin clay, for its part, is an­other product that forms a phys­i­cal bar­rier on the plant. This sub­stance works by cre­at­ing a bar­rier film which ad­heres and ir­ri­tates in­sects. It is com­monly ap­plied as a spray (e.g., Sur­round WP crop pro­tec­tant) against in­sects such as wasps, grasshop­pers, leafrol­lers, mites, thrips, some moth va­ri­eties, psylla, flea bee­tles and Ja­panese bee­tles (Grant, 2018; York, 2016). Thereby, these tech­niques may have a net pos­i­tive im­pact, since they re­duce the re­sources available for some in­ver­te­brate pop­u­la­tions to thrive.

  • Cul­tural con­trol: Th­ese meth­ods in­volve the mod­ifi­ca­tion of stan­dard farm­ing prac­tices to avoid in­sect pro­lifer­a­tion or to make the en­vi­ron­ment less fa­vor­able for them. As such, these tech­niques do not re­quire the use of spe­cial­ized crop pro­tec­tion equip­ment or skills de­signed to con­trol in­sect pop­u­la­tions. Hence, they typ­i­cally do not de­mand ex­tra la­bor and cost. How­ever, these meth­ods are not always effec­tive for pre­vent­ing in­sect over­pop­u­la­tion.

Some com­mon ex­am­ples of cul­tural con­trols are:

  • Time of sow­ing: not plant­ing dur­ing the egg-lay­ing pe­riod of an in­sect species can help con­trol in­sect pop­u­la­tions. It is a tech­nique already used for con­trol­ling some in­ver­te­brate pop­u­la­tions, such as seed­corn mag­gots.

  • Time of har­vest: the growth of in­sect and other in­ver­te­brate pop­u­la­tions can be con­trol­led by prompt har­vest­ing. This method is em­ployed to con­trol wee­vil and bruchid pop­u­la­tions in crop fields of maize and beans.

  • Crop ro­ta­tion: in this prac­tice, differ­ent types of crops are grown in the same area in se­quenced sea­sons. It is mostly done be­cause it in­creases crop yield and soil fer­til­ity. How­ever, it can also help to con­trol an in­ver­te­brate species pop­u­la­tion if a crop that is sus­cep­ti­ble to a se­ri­ous pest is fol­lowed by an­other crop that is not in this way sus­cep­ti­ble, on a ro­tat­ing ba­sis. For ex­am­ple, corn root­worm lar­vae can be starved out by re­plac­ing corn for one to two years with a non-host crop, such as soy­beans, al­falfa, or oats. Crop ro­ta­tion works best in larger ar­eas where in­sects can­not read­ily move from the old crop lo­ca­tion to the new. An im­por­tant dis­ad­van­tage of this method is that some crops re­quire spe­cial grow­ing con­di­tions and, thus, effec­tive ro­ta­tion may not be fea­si­ble.

  • San­i­ta­tion: keep­ing the area clean of plants or ma­te­ri­als that may give re­fuge to high in­sect pop­u­la­tions. Ex­am­ples in­clude col­lect­ing fallen fruits—which of­ten con­tain pu­pat­ing in­sects—and re­mov­ing weeds that may har­bor aphids, mites or whiteflies. Other crop resi­dues—such as corn stub­ble or squash vines—are com­monly used for ce­real stalk-bor­ers to pu­pate. Hence, these resi­dues should similarly be re­moved and de­stroyed. Fi­nally, the col­lec­tion and re­moval of do­mes­tic garbage and sewage are of great im­por­tance in the cur­tailing of com­mon flies and other in­sect pop­u­la­tions.

Ac­cord­ing to ex­pert opinion (i.e., Lock­wood, 2011, cited in Knutsson, 2016), when com­pared to tra­di­tional biolog­i­cal and chem­i­cal tech­niques of con­trol­ling in­sect pop­u­la­tions, cul­tural con­trols ap­pear to be the most hu­mane meth­ods.

  • Chem­i­cal meth­ods: Since the mid-1950s, chem­i­cal in­sec­ti­cides have been the main weapon against in­sect pests. Th­ese have proven to be effec­tive (high kill, rapid act­ing, pre­dictable effects) and usu­ally not too ex­pen­sive. How­ever, as noted above, com­mon in­sec­ti­cides are likely to pro­duce high amounts of di­rect suffer­ing. If we have to kill in­sects, we should do it as painlessly as pos­si­ble. In this re­gard, Wild An­i­mal Ini­ti­a­tive (WAI) is in­ves­ti­gat­ing the fea­si­bil­ity of hu­mane in­sec­ti­cides. WAI aims to iden­tify in­sec­ti­cides that kill faster, less painfully, or both, avoid­ing po­ten­tially nega­tive down­stream ecolog­i­cal effects (Howe, 2019; Rowe, 2018).

To date, WAI has de­vel­oped a database of 255 com­monly used in­sec­ti­cides. “After an ex­ten­sive re­view of the liter­a­ture on pain and sen­tience in in­sects”, they are cur­rently “re­view­ing the mechanism by which each of these in­sec­ti­cides kill.” Ad­di­tion­ally, they are “eval­u­at­ing the rel­a­tive painful­ness of each, or at a min­i­mum iden­ti­fy­ing where fur­ther re­search is needed to un­der­stand what in­sec­ti­cides might be the least painful” (Wild An­i­mal Ini­ti­a­tive, 2019). Ac­cord­ing to Hol­lis Howe (2019), lead­ing re­searcher of the pro­gram, “the enor­mous num­ber of in­sects to­gether with the like­li­hood that their welfare is poor means that the po­ten­tial im­pact of such in­ter­ven­tions [hu­mane in­sec­ti­cides] is high”. WAI is also out­reach­ing ex­perts to as­sess the vi­a­bil­ity of the pro­ject. If hu­mane in­sec­ti­cides can over­come the prob­lems of con­ven­tional in­sec­ti­cides (i.e., in­sect re­sis­tance, con­tam­i­na­tion risks and po­ten­tial nega­tive effects on hu­man health, see Hen­drichs, 2000; Thul­lner, 1997), they could be an effec­tive and com­pet­i­tive al­ter­na­tive for con­trol­ling in­sect pop­u­la­tions.

If in­sect eggs and/​or lar­vae do not have the ca­pac­ity to ex­pe­rience pain and plea­sure in a morally sig­nifi­cant way, the spe­cific use of ovi­cides and/​or lar­vi­cides should be con­sid­ered prefer­able to tra­di­tional in­sec­ti­cides ad­dressed to adult in­di­vi­d­u­als. Ad­di­tion­ally, kil­ling ju­ve­nile in­sects be­fore their pop­u­la­tion in­creases im­plies many fewer deaths than if the pop­u­la­tion is oth­er­wise not con­trol­led.

Other chem­i­cal con­trol meth­ods in­volve us­ing her­bicides to kill un­wanted plants—which for many in­sects are lar­val or adult host­plants (Carere & Mather, 2019). It may be hy­poth­e­sized that the use of her­bicides has a net pos­i­tive im­pact, since these sub­stances elimi­nate the plant en­ergy that feeds in­sects and other arthro­pods, and hence, re­duce the re­sources available for in­ver­te­brate pop­u­la­tions to thrive. Re­pel­lants used on plants may have a similar effect, since in­sects might al­ight but will not feed from the plant and end up leav­ing. How­ever, re­pel­led in­sects will prob­a­bly move off to an­other plant. There­fore, the use of these sub­stances does not ap­pear to be an effec­tive solu­tion.

Lastly, an­other com­mon method of chem­i­cal con­trol con­sists in us­ing chem­i­cals that in­hibit in­sect feed­ing, mat­ing, or other es­sen­tial be­hav­iors. Th­ese chem­i­cals can be nat­u­ral prod­ucts, syn­the­sized mimics of nat­u­ral prod­ucts, or com­pletely syn­thetic ma­te­ri­als. In this re­gard, two types of sub­stances should be high­lighted: an­tifeedants and pheromones.

An­tifeedants are chem­i­cals that block part of the feed­ing re­sponse of phy­tophagous in­sects or other arthro­pods (e.g., cater­pillars). A more re­stric­tive defi­ni­tion is pro­vided by Is­man (2002, based on Is­man et al., 1996), for whom an an­tifeedant is “a be­havi­our-mod­ify­ing sub­stance that de­ters feed­ing through a di­rect ac­tion on periph­eral sen­silla (= taste or­gans) in in­sects” (152). Th­ese tech­niques aim to block any as­pect of the feed­ing re­sponse: from in­terfer­ing in how the in­sect al­ights on the fo­li­age to al­ter­ing the ol­fac­tory and tast­ing char­ac­ter­is­tics of the plant. The main ad­van­tage of an­tifeedants is that they do not seem to harm in­sects—at least, not di­rectly. How­ever, they are not always effec­tive. First, an­tifeedants may have a de­ter­rent effect for a spe­cific in­sect species, while other in­sects might be com­pletely in­sen­si­tive to their effects. Se­cond, it has been ob­served that in­sects ini­tially de­terred by an an­tifeedant, be­come in­creas­ingly tol­er­ant upon re­peated or con­tin­u­ous ex­po­sures (Is­man, 2002). In gen­eral, an­tifeedants are bet­ter recom­mended as a tech­nique that should be com­bined with other meth­ods, as part of an in­te­grated pest man­age­ment sys­tem (Is­man, 2002; Ley, 1990).

For their part, pheromones (glan­du­lar se­cre­tions used for com­mu­ni­ca­tion be­tween in­di­vi­d­u­als within the same species) of differ­ent types can act as re­pel­lents or as at­trac­tants. In the lat­ter case, they are used as part of trap­ping meth­ods. How­ever, what is of spe­cial in­ter­est are the effects of sex pheromones. If a given area is flooded with a sex pheromone, males are un­able to lo­cate vir­gin fe­males, and there­fore, mat­ing is dis­rupted. This method (called ‘dis­rup­tion tech­nique’ or ‘mat­ing dis­rup­tion’) has been used by the Divi­sion of Forestry Pro­grams in Wis­con­sin, US, to slow down the pop­u­la­tion growth of gypsy moths. As part of the “Slow-The-Spread” pro­gram, moth pheromones are sprayed from air­planes in or­der to treat large ar­eas where moths are spread­ing (Wis­con­sin DNR Forestry News, 2017).

A few such prod­ucts are com­mer­cially available for other in­sects, such as the codling moth, which af­fects ap­ples. Fur­ther de­vel­op­ments in mat­ing dis­rup­tion for other species ap­pear to be a promis­ing area for the effec­tive and hu­mane con­trol of in­sect pop­u­la­tions. How­ever, it should be con­sid­ered that this prac­tice works best in large com­mer­cial fields where it is less likely that mated fe­males will move into the plant­ing from out­side of the treated area. Ad­di­tion­ally, many of these types of be­hav­ioral chem­i­cals break down or wash away quickly. There­fore, they must be de­signed for slow re­lease over a long pe­riod, for use in an en­closed area or for fre­quent em­ploy­ment.

  • Biolog­i­cal meth­ods: In gen­eral, biolog­i­cal con­trol refers to differ­ent meth­ods of in­sect and mite pop­u­la­tion con­trol through other or­ganisms. Typ­i­cally, they con­sist in the in­tro­duc­tion of ‘biolog­i­cal con­trol agents’ (nat­u­ral en­e­mies) of the tar­get species, which in­clude preda­tors, par­a­sitic in­sects, and in­sect pathogens.

An in­ter­est­ing method of biolog­i­cal con­trol is the ster­ile in­sect tech­nique (SIT, also known as ‘au­to­cide’, ‘ster­ile male tech­nique’ (SMT), or ‘ster­ile in­sect re­lease method’ (SIRM)). Through SIT, large num­ber of male in­sects such as flies (screw-worm flies, fruit flies) and moths (e.g., pink bol­l­worm moths) are ster­il­ized with­out af­fect­ing their sex­ual be­hav­ior. Usu­ally, they are ster­il­ized us­ing ioniz­ing ra­di­a­tions (X-rays, gamma-rays). After the ster­il­iza­tion, male in­sects are re­leased in crop fields, at a ra­tio that effec­tively “in­un­dates” the tar­get species. As ster­ile males out­num­ber nor­mal males, most fe­males there­fore mate with ster­ile males and pro­duce no offspring, re­duc­ing the fu­ture pop­u­la­tion of the species at is­sue (Dyck et al., 2015; Hill, 1997).

This method has been used for around 60 years, and has proven suc­cess­ful against fruit flies, screw-worm flies and many other in­sects (mostly, flies and moths, see Dyck et al., 2015; FAO, 1991; Hen­drichs, 2000; Hill, 1997). Since the 1990s, the FAO has openly sup­ported the im­ple­men­ta­tion of SITs, given their effec­tive­ness and the prob­lems as­so­ci­ated with the overuse of con­ven­tional in­sec­ti­cides (Hen­drichs, 2000; Thul­lner, 1997)[5]. Cur­rently, SITs are em­ployed wor­ld­wide.

Ad­di­tion­ally, SITs have been im­ple­mented to con­trol par­a­sites and dis­eases trans­mit­ted to hu­mans by in­sects (e.g., Afri­can try­panoso­mi­a­sis, also known as ‘sleep­ing sick­ness’, trans­mit­ted by the tsetse fly; Feld­mann & Hen­drichs, 2001). In­sects like screw-worm flies, or screw-worms for short (Cochliomyia ho­minivo­rax), for in­stance, do not only at­tack crops but can also par­a­site hu­mans and other warm-blooded an­i­mals[6]. In this case, SITs have been proved to be an effec­tive and hu­mane way of con­trol­ling screw-worm fly pop­u­la­tions, pro­tect­ing hu­mans but also do­mes­ti­cated an­i­mals and an­i­mals liv­ing in the wild from screw-worm in­fes­ta­tion (see e.g. Ra­jew­ski, 2017). Similarly, SITs have been pi­loted against mosquito vec­tors of the Zika, yel­low fever, chikun­gunya and dengue viruses (Vrey­sen et al., 2007).

For a long-last­ing effect, SITs re­quire the con­tin­u­ous re­lease of ster­ile males in over­whelming num­bers over sev­eral con­sec­u­tive gen­er­a­tions (FAO, 1991). Re­cently, this tech­nique has been im­proved with CRISPR gene drives in mosquitoes (genus Anophe­les). CRISPR tech­nol­ogy is a sim­ple yet pow­er­ful tool for edit­ing genomes. It al­lows re­searchers to eas­ily al­ter DNA se­quences and mod­ify gene func­tion. By chang­ing the DNA of a few in­di­vi­d­u­als, the mod­ifi­ca­tion can be spread through­out an en­tire pop­u­la­tion (Vidyasagar, 2018).

In this case, CRISPR is be­ing used to mod­ify the three species of mosquitoes most re­spon­si­ble for malaria trans­mis­sion—Anophe­les gam­biae, Anophe­les coluzzii, and Anophe­les ara­bi­en­sis. This does not in­volve their ster­il­iza­tion, but the dra­matic re­duc­tion of the pro­por­tion of fe­male offspring (to no more than 10%). It is ex­pected that this in­no­va­tion will re­duce the over­all pop­u­la­tion of Anophe­les, as well as the in­ci­dence of malaria–as it is fe­male mosquitoes who trans­mit the dis­ease (Mun­henga, 2018; Vrey­sen et al., 2007). Un­like tra­di­tional SITs, this new ap­proach ap­pears to be more cost-effec­tive since, ac­cord­ing to Delphine Thizy–di­rec­tor of Tar­get Malaria, the non-profit re­search con­sor­tium be­hind an im­ple­men­ta­tion of this in Burk­ina Faso– “you don’t need to con­stantly re­lease more mosquitoes” (Newey, 2018).

This ini­ti­a­tive is still in its pi­lot phase. How­ever, it has many po­ten­tial ap­pli­ca­tions that could tar­get other in­sects or in­ver­te­brates liv­ing in the wild.

In gen­eral, meth­ods for con­trol­ling in­sect pop­u­la­tions have as their main ob­jec­tive to in­crease agri­cul­tural pro­duc­tivity (van Em­den & Peakall, 1996). There is lit­tle ev­i­dence of their effects on the well-be­ing of in­sects and other arthro­pods, and much less about their con­se­quences for non-arthro­pod in­ver­te­brates. For in­stance, it can be hy­poth­e­sized that al­though re­pel­lants/​an­tifeedants, or phys­i­cal and cul­tural con­trol meth­ods do not di­rectly cause painful deaths, in­di­rectly, they can cause equal or even more painful ways to die. Since these meth­ods re­move food and shelter that in­ver­te­brates rely upon, it is prob­a­ble that their pop­u­la­tions are checked not only be­cause the an­i­mals fail to re­pro­duce but also be­cause they die of star­va­tion, ex­po­sure, or pre­da­tion. For the time be­ing, we do not know if these deaths are bet­ter than deaths by ex­po­sure to organophos­phate or pyrethroid in­sec­ti­cides, for ex­am­ple (Hol­lis Howe, per­sonal com­mu­ni­ca­tion, 7 Novem­ber 2019). Hence, fur­ther re­search is needed to dis­cern which tech­niques, or which com­bi­na­tion of them[7], may pro­duce the least pos­si­ble suffer­ing, con­sid­er­ing as well their im­pact on an­i­mal pop­u­la­tion dy­nam­ics.

With these pre­cau­tions in mind, the fol­low­ing table (fig. 1) sum­ma­rizes the meth­ods re­viewed above that are likely to cause less suffer­ing than in­sec­ti­cides and other tra­di­tional ap­proaches:

Fig. 1. In­sect and other in­ver­te­brate pop­u­la­tion con­trol meth­ods: some tech­niques that are likely to cause less suffer­ing than tra­di­tional in­sec­ti­cides and other similar ap­proaches.

In­ver­te­brates un­der hu­man control

In this sec­tion I dis­cuss the main ac­tivi­ties in which hu­mans use, and some­times kill, in­ver­te­brates. A brief de­scrip­tion of each of these uses is given. When pos­si­ble, al­ter­na­tives to re­duce in­ver­te­brate suffer­ing are pre­sented. In other cases, I sug­gest ques­tions that need to be in­ves­ti­gated in or­der to bet­ter un­der­stand the prob­lem and de­sign pos­si­ble in­ter­ven­tion strate­gies.

1. Research

In­ver­te­brates are used in field re­search on bio­di­ver­sity and con­ser­va­tion and as lab­o­ra­tory mod­els for the biolog­i­cal sys­tems of other an­i­mals, in­clud­ing hu­mans (Carere et al., 2011; Carere & Mather, 2019). In lab­o­ra­to­ries, some of the most com­mon in­ver­te­brates are fruit flies (Drosophila melanogaster), the ne­ma­tode C. el­e­gans, honey bees (Apis), and to a lesser ex­tent, the coe­len­ter­ate Ne­matostella and jump­ing spi­ders (fam­ily Salti­ci­dae). Other in­ver­te­brate an­i­mals used in neu­ro­biol­ogy are Loligo squids, Li­mu­lus horse­shoe crabs and sea hares (Aplysia). In­ver­te­brate use in re­search will prob­a­bly con­tinue, and even in­crease, in the fu­ture (Carere & Mather, 2019; Pollo & Vi­tale, 2019).

In most coun­tries, in­ver­te­brates are not gen­er­ally cov­ered by an­i­mal welfare laws. In the United States, for ex­am­ple, there are no offi­cial re­quire­ments for us­ing in­sects in re­search or, ap­par­ently, for us­ing any other in­ver­te­brate (see the web­site of the Office of Lab­o­ra­tory An­i­mal Welfare (2019) of the US Govern­ment). Hence, no record is usu­ally kept of how many in­ver­te­brates are used in ex­per­i­men­ta­tion. How­ever, re­searchers do have to keep some track of the an­i­mals used, ex­clu­sively for sci­en­tific rea­sons –as part of the meth­ods fol­lowed in a study. Still, the num­bers of an­i­mals used in sci­en­tific re­ports or pa­pers are far less than the to­tal num­ber of an­i­mals in­volved in a study for a va­ri­ety of rea­sons. For ex­am­ple, they do not in­clude an­i­mals that re­searchers used for train­ing pur­poses or an­i­mals that re­searchers used for the study but were “dis­carded.” More­over, the num­ber of “dis­carded” an­i­mals can vary wildly be­tween stud­ies, species, and de­pend­ing on the care­ful­ness of the ex­per­i­menter. Ad­di­tion­ally, this ap­proach does not in­clude the an­i­mals used or kil­led for stud­ies that never got pub­lished for what­ever rea­son. Thus, the num­ber of in­ver­te­brates used in re­search is prob­a­bly higher than the num­ber of an­i­mals re­ported in sci­en­tific pa­pers. In this re­gard, an­other start­ing point for es­ti­mat­ing the num­ber of in­ver­te­brates used in re­search would be to iden­tify the ma­jor sup­pli­ers and ask them how many in­sects and other in­ver­te­brates they sell to lab­o­ra­to­ries, uni­ver­si­ties and other rele­vant in­sti­tu­tions (Michelle Gra­ham, per­sonal com­mu­ni­ca­tion, 11 Novem­ber 2019).

On the other hand, some coun­tries or re­gions have ap­proved leg­is­la­tion or pro­to­cols on hus­bandry, han­dling, and eu­thana­sia for some in­ver­te­brates used in re­search (e.g., United King­dom, Nor­way, Switzer­land, the Euro­pean Union). In these cases, ob­tain­ing es­ti­mates of the in­ver­te­brates that are pro­tected by ex­ist­ing leg­is­la­tion is not difficult. Thus, for ex­am­ple, I had pre­vi­ously es­ti­mated that sci­en­tific and ed­u­ca­tional ex­per­i­ments with cephalopods in Spain ranged from 0 to a max­i­mum of 15,848 an­nu­ally, for the pe­riod 2009-2017 (see here –note that the spread­sheet is in Span­ish). How­ever, these figures are prob­a­bly not rep­re­sen­ta­tive of the num­ber of other smaller in­ver­te­brates used for re­search.

Th­ese manda­tory or recom­mended pro­ce­dures for the treat­ment of in­ver­te­brates used for re­search could be pro­moted in other re­gions. Similarly, the prin­ci­ples of Re­place­ment, Re­duc­tion, and Refine­ment (the “Three Rs”) for the use of an­i­mals in sci­en­tific re­search could be ap­plied to in­ver­te­brates as well. In this sense, spe­cific strate­gies to achieve the Three R’s when plan­ning pro­jects that in­volve the use of in­ver­te­brates—e.g., oc­to­puses—should be de­vel­oped (Har­vey-Clark, 2011).

2. Food production

2.1. Crop cul­ti­va­tion for hu­man and an­i­mal con­sump­tion: No data was found on the mag­ni­tude of the fol­low­ing uses of in­ver­te­brate an­i­mals:

2.1.1. In­ver­te­brates reared to be used as biolog­i­cal con­trol agents: As ex­plained above, these are preda­tors or par­a­sitic in­sects used to check in­ver­te­brate pop­u­la­tions. Preda­tors may be in­sects or other in­sec­tivorous an­i­mals, each of which con­sume many in­sect prey dur­ing their life­time (Mahr, 2007). A great va­ri­ety of preda­tor in­sects are reared to con­trol in­sect pop­u­la­tions in crop fields, green­houses and pri­vate house­holds (Bop­pré & Vane-Wright, 2019; Mo­rales-Ramos et al., 2014).

Par­a­sites of in­sects, for their part, are other in­sects—like par­a­sitoid wasps (genus En­car­sia)—which lay their eggs in or on the host in­sect. When the par­a­site egg hatches, the young par­a­site larva feeds on the host (the tar­get in­sect) and kills them. Usu­ally one host is suffi­cient to feed the im­ma­ture par­a­site un­til they be­come an adult (Mahr, 2007; Mo­rales-Ramos et al., 2014; Sithanan­tham et al., 2013). Par­a­site in­sects like phy­tophagous wasps (genus Te­tramesa), moths (genus Cac­to­blastis) and phy­tophagous flies (genus Urophora) are also used to com­bat ex­otic weeds. This is of­ten un­suc­cess­ful and poses an en­vi­ron­men­tal risk since it can af­fect non-tar­get or­ganisms (Bop­pré & Vane-Wright, 2019; Cap­in­era, 2008; Mo­ran et al., 2014; Pear­son & Cal­l­away, 2003).

2.1.2. In­ver­te­brates reared for use in ster­ile in­sect tech­nique (SIT): As already ex­plained, male in­sects such as flies (screw-worm flies, fruit flies) and moths (e.g. pink bol­l­worm moths) are reared, ster­il­ized us­ing ioniz­ing ra­di­a­tions (X-rays, gamma-rays) and re­leased in crop fields to re­duce the fu­ture pop­u­la­tions of those species (Dyck et al., 2015; Hill, 1997).

2.1.2. In­ver­te­brates used for pol­li­na­tion: Honey bees and other pol­li­na­tor in­sects are reared by crop in­dus­tries. Soli­tary bees and bum­ble bees are then re­leased to sup­port pol­li­na­tion efforts. It is ex­pected that the so-called “pol­li­na­tor crisis” will re­sult in the breed­ing and re­lease of even a higher num­ber of bees (Bop­pré & Vane-Wright, 2019).

2.2. In­ver­te­brates in aqua­cul­ture and fish­ing: In­ver­te­brates such as shrimps, clams, squids, lo­custs, crabs, marine snails, oc­to­puses and crayfish serve as a ma­jor source of hu­man food wor­ld­wide. Fish­count (2019a) es­ti­mates that 30-56 billion crayfish, crabs and lob­sters, and 190-470 billion shrimps and prawns were kil­led in aqua­cul­ture pro­duc­tion in 2015. Th­ese num­bers do not in­clude an­i­mals who died pre-slaugh­ter, mean­ing the ac­tual num­ber of kil­led crus­taceans is higher. How­ever, de­tailed and ac­cu­rate data about how many aquatic in­ver­te­brates are wild-caught (by species and coun­try) is an im­por­tant is­sue that should be fur­ther in­ves­ti­gated.

More­over, there is a strong mar­ket de­mand for oc­to­puses, and im­por­tant in­vest­ments for de­vel­op­ing in­ten­sive oc­to­pus farms, in Med­iter­ranean, South Amer­i­can and Asian coun­tries—es­pe­cially in Spain, Chile and China (see Igle­sias et al., 2004; Jac­quet et al., 2019; Piper, 2019). How likely is it that the in­dus­try will suc­ceed in its efforts to raise oc­to­puses in in­dus­trial fa­cil­ities? What does the fu­ture for this in­dus­try look like? What is the in­dus­try’s niche mar­ket? What will the im­pact of this in­dus­try on other marine an­i­mals used to feed oc­to­puses be? What are the prospects of this prac­tice spread­ing to other cephalopods? Given the rel­a­tively strong ev­i­dence that cephalopods (i.e., oc­to­puses, cut­tlefish, and squid) are con­scious (see In­ver­te­brate Sen­tience: Sum­mary of find­ings, Part 2), the use of these an­i­mals for in­dus­trial food pro­duc­tion will con­sti­tute a very im­por­tant an­i­mal welfare prob­lem.

In 2017, Carder pub­lished a pre­limi­nary study into lob­ster welfare in the United King­dom. She found that lob­sters were fre­quently over­crowded, de­nied shelter, and sub­jected to un­suit­ably bright light. Carder (2017) also recom­mend re­search on the welfare of lob­sters and other de­ca­pod crus­taceans, when housed in tanks, dur­ing cap­ture, han­dling and trans­port. “Such in­for­ma­tion can be used to in­form leg­is­la­tive change” (Carder, 2017: 067).

At pre­sent, the most com­mon meth­ods of slaugh­ter­ing crus­taceans and cephalopods in­clude split­ting, spik­ing, chilling, boiling, gassing, “drown­ing,” and us­ing chem­i­cals or elec­tric­ity. Th­ese meth­ods are ap­plied with­out prior stun­ning and do not cause im­me­di­ate death. Hence, they are likely to pro­duce pain and dis­tress (EFSA, 2005; Fish­count, 2019b; Yue, 2008). In some coun­tries, for ex­am­ple New Zealand, the hu­mane kil­ling of oc­to­puses and some species of crus­taceans is manda­tory un­der the An­i­mal Welfare Act 1999 (re­in­forced last year through the An­i­mal Welfare (Care and Pro­ce­dures) Reg­u­la­tions 2018). New tech­nolo­gies, such as im­mer­sion in clove oil bath and elec­tri­cal meth­ods, may im­prove the welfare of these an­i­mals dur­ing slaugh­ter.

Clove oil is be­com­ing a pop­u­lar anes­thetic for pro­ce­dures such as han­dling and trans­port­ing some aquatic an­i­mals, and has been suc­cess­fully tested on var­i­ous species of fishes (Tay­lor & Roberts, 1998) and oc­to­puses (Seol et al., 2007). Re­gard­ing crabs, clove oil has been shown to im­mo­bi­lize them with­out ap­par­ent signs of dis­tress (Mor­gan et al., 2001 in Yue, 2008). Thus, the use of this sub­stance could be more widely pro­moted for oc­to­puses and may be used effec­tively to kill crus­taceans like crabs (EFSA, 2005; Gard­ner, 1997). How­ever, ad­di­tional re­search is needed to bet­ter as­sess clove oil effec­tive­ness in crus­taceans in gen­eral (Yue, 2008). Ad­di­tion­ally, oth­ers claim that it is not yet clear whether clove oil and other anaes­thetic agents (i.e., AQUI-S) are safe for hu­man con­sump­tion (RSPCA, 2018).

Re­gard­ing elec­tri­cal meth­ods, the Crus­tas­tun elec­tri­cal stun­ning and kil­ling sys­tem (see Mitchell & Cooper, 2019) is known to be effec­tive and more hu­mane than tra­di­tional method (Yue, 2008). This de­vice de­stroys the an­i­mal’s ner­vous sys­tem within half a sec­ond, thus not al­low­ing their pain re­cep­tors to work. Death en­sues in all crabs, lan­goustines and lob­sters within 5-10 sec­onds. Since New Zealand, Switzer­land and the city of Reg­gio Emilia (in north­ern Italy) banned boiling crus­taceans al­ive (Street, 2018), the use of Crus­tas­tun is ex­pand­ing. It is re­ported that Waitrose, Tesco and ma­jor su­per­mar­kets in the United King­dom claim that this method is used in all shel­lfish prod­ucts sup­plied to them (Fish­count, 2019a; Griffiths & White, 2012). Tesco’s own brand of crab and lob­ster as­sures that they stun the an­i­mals prior to slaugh­ter. Waitrose, for its part, stuns their brown crabs (Cancer pagu­rus) and lob­sters as well. Some restau­rants in the UK such as Lo­canda Lo­catelli and Quo Vadis have com­mit­ted to us­ing the Crus­tas­tun (Crus­tacean Com­pas­sion, 2019).

Fur­ther­more, sci­en­tists in Nor­way have adapted the com­mer­cial dry stun­ner for fishes (Stansas, by the equip­ment man­u­fac­turer Seaside) for the hu­mane kil­ling of crabs in bulk (Roth & Grimsbo, 2013). This new tech­nol­ogy is in line with new Nor­we­gian an­i­mal welfare reg­u­la­tion and al­lows for eas­ier han­dling of the an­i­mals dur­ing pro­cess­ing (Berg-Ja­cob­sen, 2014).

Th­ese meth­ods and oth­ers were dis­cussed by the Aus­tralian Royal So­ciety for the Preven­tion of Cru­elty to An­i­mals (RSPCA, 2018). The or­ga­ni­za­tion con­cludes that “fur­ther re­search is re­quired be­fore defini­tive con­clu­sions can be drawn about the hu­mane­ness of stun­ning and kil­ling meth­ods for crus­taceans” (RSPCA, 2018). For its part, the Hu­mane Slaugh­ter As­so­ci­a­tion (HSA) is fund­ing sci­en­tific re­search to im­prove the welfare of farmed fin­fishes, de­ca­pod crus­taceans and/​or coleoid cephalopods dur­ing slaugh­ter. The HSA is try­ing to bet­ter un­der­stand and im­prove the welfare of these farmed an­i­mals whilst un­der­go­ing slaugh­ter for food pro­duc­tion (HSA, 2018).

In par­allel, the start-up New Wave Foods is pro­duc­ing plant-based shrimps from sea­weed, soy pro­tein, and nat­u­ral fla­vors. The com­pany, founded in 2015, offers “a rapidly-scal­able al­ter­na­tive that uses in­gre­di­ents and tech­nol­ogy con­sumers rec­og­nize,” ac­cord­ing to Do­minique Barnes (2018 in Wat­son, 2018), one of its co-founders. From a busi­ness per­spec­tive, New Wave has con­sid­er­able chances of suc­cess. First, in tonnes, shrimp is one of the most con­sumed ‘seafood’ in the world. Se­cond, New Wave is one of the few com­pa­nies try­ing to com­mer­cial­ize crus­tacean sub­sti­tutes, fac­ing al­most no com­peti­tors. Re­cently, Tyson Foods–one of the ma­jor meat pro­cess­ing com­pa­nies wor­ld­wide–in­vested in the start-up. Tyson will lev­er­age its scale and net­work to help ac­cel­er­ate New Wave’s growth. Fur­ther­more, af­ter shrimp, New Wave is plan­ning to de­velop plant-based crab and lob­ster (Lu­cas, 2019).

2.3. Land in­ver­te­brates for hu­man con­sump­tion:

2.3.1 In­sect farm­ing: In­sects of cer­tain species have been eaten by hu­mans since pre­his­toric times (van Huis et al., 2013; van Huis, 2017). Their use as food con­tinues to be wide­spread in trop­i­cal and sub­trop­i­cal coun­tries, like Thailand (Van Huis et al., 2013; FAO, 2013; Shock­ley & Dossey, 2014 in Mo­rales-Ramos et al., 2014). After a UN Food and Agri­cul­ture Or­ga­ni­za­tion in-depth re­port about ed­ible in­sects (van Huis et al., 2013), there has been in­creas­ing in­ter­est in en­to­mophagy (in­sect con­sump­tion) in the United States and Europe (re­gard­ing the Euro­pean Union, see Reg­u­la­tion No 2015/​2283). Mainly, it is ar­gued that the ed­ible in­sect in­dus­try might provide an en­vi­ron­men­tally sound al­ter­na­tive to tra­di­tional an­i­mal pro­tein (Ger­hardt et al., 2019; van Huis et al., 2013). How­ever, the in­dus­try faces nega­tive con­sumer per­cep­tion of in­sects as a food source in most Western coun­tries (Ger­hardt et al., 2019)[8].

Nowa­days, in­sect-based prod­ucts for hu­man con­sump­tion range from pro­tein bars, in­sect pow­der, snacks, crisp­bread pasta, in­sect in­fused beer, bit­ters, smooth­ies and burg­ers (Bug Burger, 2019). There are no es­ti­mates of how many in­sects are farmed an­nu­ally for hu­man con­sump­tion. Although which species are con­sumed varies by re­gion, it seems to be that bee­tles are one of the most eaten in­sects (van Huis et al., 2013). In Euro­pean coun­tries, crick­ets of differ­ent species and meal­worms (the lar­val form of the meal­worm bee­tle, Tene­brio moli­tor) are com­mer­cial­ized as well (Euro­pean Com­mis­sion, 2019).

Cur­rently, a team of sci­en­tists at Tufts Univer­sity in the United States is de­vel­op­ing lab-grown in­sect meat, or as they call it, “en­to­mo­cul­ture”. Ac­cord­ing to Ru­bio et al. (2019), less de­mand­ing en­vi­ron­ments are needed to grow in­sects com­pared to mam­mals and birds. Ad­di­tion­ally, in­sects re­quire less en­ergy and are bet­ter suited for lab spaces, such as ver­ti­cal sys­tems. At pre­sent, re­search is on­go­ing to mas­ter two key pro­cesses: con­trol­ling the de­vel­op­ment of in­sect cells into mus­cle and fat, and com­bin­ing these in 3D cul­tures with a meat-like tex­ture. In the fu­ture, in­sect meat could even be mod­ified to taste like lob­ster, crab or shrimp due to the evolu­tion­ary prox­im­ity of in­sects and crus­taceans.

2.3.2. Snail meat and snail caviar: Land snails are con­sumed by hu­mans in many cul­tures. They com­monly are cooked al­ive, which is prob­a­bly ex­tremely painful, as­sum­ing they are con­scious in­di­vi­d­u­als (To­masik, 2017b). Ad­di­tion­ally, dur­ing the past years, there has been a grow­ing in­ter­est in snail caviar as a lux­ury food item across Europe (Gen­er­al­i­tat de Catalunya, 2010; Ran­dle et al., 2017).

In 2017, global snail pro­duc­tion amounted to 18,331 tonnes (FAO, 2019). How­ever, for 2016, the FAO (2019b) es­ti­mated a to­tal pro­duc­tion of 17,970 tonnes of snails[9], while a sec­tor source claims that the global snail mar­ket amounted to 43,000 tonnes (In­dexbox, 2018 in Food Dive, 2018). In an up­com­ing re­port by Re­think Pri­ori­ties, we dis­cuss these figures and other is­sues in­volved in the use of snails as food.

2.3.3. Carmine (or cochineal): This pig­ment is pro­duced from some scale in­sects (small in­sects of the or­der Hemiptera, sub­or­der Ster­n­or­rhyn­cha) such as the cochineal scale (Dacty­lopius coc­cus) and cer­tain Por­phy­rophora species (Ar­me­nian cochineal and Pol­ish cochineal). Usu­ally la­beled as ‘E-120’, carmine is used in cos­met­ics, per­sonal care prod­ucts, as a food col­or­ing—e.g. in juices, yo­gurts and can­dies–, and in some med­i­ca­tions (Green­hawt et al., 2009). It is es­ti­mated that the typ­i­cal per-cap­ita num­ber of cochineal bugs kil­led by con­sumers in rich coun­tries is around 120 per year (To­masik, 2017c).

There are plant-based al­ter­na­tives to carmine, such as ly­copene (a tomato-based ex­tract) be­tanin (ob­tained from beet­roots) and ex­tract from berries. After cus­tomer pres­sure, Star­bucks moved away from carmine in 2012 (So­te­riou & Smale, 2018). The above sug­gests that similar pe­ti­tions in this re­gard could be effec­tive.

2.3.3. Honey, royal jelly and beeswax: Ac­cord­ing to the FAO (2019b), in 2017 there were 90,999,730 bee­hives wor­ld­wide[10]. Dur­ing the same year, 42,307 tonnes of beeswax and 1,860,712 tonnes of honey were pro­duced (FAO, 2019). Hwang (2017) es­ti­mated that around 888,568,235,294 honey bees were used for honey pro­duc­tion globally in 2014 (1,510,566 tonnes). In an up­com­ing re­port by Re­think Pri­ori­ties, we es­ti­mate that at any given time in 2017 there were be­tween 1.4 and 4.8 trillion adult man­aged honey bees.

2.4. In­ver­te­brates as food for other an­i­mals: No data was found on the mag­ni­tude of the fol­low­ing uses of in­ver­te­brate an­i­mals:

2.4.1. In­ver­te­brates as aqua­cul­ture feed: Some in­ver­te­brates—i.e. krill and in­sects—are used as aqua­cul­ture feed. Most of the krill caught in com­mer­cial fish­eries is used for aqua­cul­ture feed. Only a small per­centage is pre­pared for hu­man con­sump­tion (FAO, 1997). Some of the most used species are the Antarc­tic krill Euphau­sia su­perba and the North Pa­cific krill Euphau­sia paci­fica (Atk­in­son et al., 2009; FAO, 1997). Sev­eral species, es­pe­cially E. su­perba, are likely to be in­creas­ingly used given the ex­pected growth of aqua­cul­ture in the fu­ture (Nay­lor et al., 2009).

In­sects, for their part, are used to cover in part the nu­tri­tional needs of fishes and crus­taceans reared in aqua­cul­ture (Rid­dick, 2014 in Mo­rales-Ramos et al., 2014). In­sect farm­ing for aquafeed is still at an early stage of de­vel­op­ment (Fletcher & How­ell, 2019; Tran et al., 2015). Since July 2017, Euro­pean Union leg­is­la­tion al­lows an­i­mals in aqua­cul­ture to be fed with pro­cessed an­i­mal pro­tein (PAP) from in­sects (Reg­u­la­tion No 2017893).

2.4.2. In­sects as food for land an­i­mals in farms: Saprophagous flies are reared on an­i­mal dung and/​or or­ganic waste in in­creas­ing amounts to re­cy­cle it and ob­tain, at the same time, a sub­sti­tute for fish to feed chick­ens (Bop­pré & Vane-Wright, 2019; Hus­sein et al., 2017; Khusro et al., 2012). In Europe, the Euro­pean Com­mis­sion is cur­rently ex­plor­ing the pos­si­bil­ity to au­tho­rize the use of PAP from in­sects to feed chick­ens and pigs (IPIFF, 2019). How de­vel­oped and wide­spread are in­dus­trial-scale pro­cesses for the pro­duc­tion of in­sect-based diets for other farmed an­i­mals is an is­sue that mer­its fur­ther re­search.

2.4.3. In­sects as pet food: A limited, but grow­ing, num­ber of pet food prod­ucts based on in­sects is available in the mar­ket, in­clud­ing cat food, dog food, and pet treats (see Coates, 2019; Smithers, 2019). Pet food com­pa­nies in the United States, United King­dom, and Ger­many already in­clude in­sects in their feed for­mula, no­tably as a means to di­ver­sify their prod­ucts. At least in Europe, this trend is ex­pected to con­tinue to grow in the next few years (IPIFF, 2018; Smithers, 2019).

2.4.4. In­ver­te­brates used as food for other pur­poses: In­ver­te­brates –mostly in­sects such as crick­ets, lo­custs, and meal­worms– are com­mer­cially reared on a large scale in or­der to feed small an­i­mals in zoos, aquar­iums and lab­o­ra­to­ries (Bop­pré & Vane-Wright, 2019).

3. En­ter­tain­ment and hobbies

3.1. Dis­plays in aquaria or in­sec­tar­iums: Live ex­hibits in zoos and mu­se­ums, usu­ally with ed­u­ca­tional pur­poses (Bop­pré and Vane-Wright, 2012; Bop­pré & Vane-Wright, 2019). No in­for­ma­tion was found on the mag­ni­tude of this prob­lem.

3.2. Col­lec­tion: Ama­teur en­to­mol­o­gists have long reared in­sects in cap­tivity for col­lec­tions. In­sect afi­ciona­dos also keep var­i­ous in­sects as pets—an in­creas­ing trend due to wider availa­bil­ity of in­ter­est­ing ex­otic species. Usu­ally, this prac­tice in­volves a re­duced num­ber of in­di­vi­d­u­als (Bop­pré & Vane-Wright, 2019).

3.3. In­ver­te­brates used as fish­ing bait: A va­ri­ety of in­ver­te­brates, such as worms (Lum­bri­cus ter­restris), krill, differ­ent in­sects and leeches are used to at­tract and catch fishes (FAO, 1997; Mie­sen & Hauge, 2004). It should be noted that ar­tifi­cial baits are also used for sport fish­ing (see e.g. Si­monds, 2016; Wik­iHow, 2019).

3.4. Fun and dec­o­ra­tion: For cer­e­mo­nial re­lease at wed­dings, funer­als, birth­day par­ties (Bop­pré & Vane-Wright, 2019; Pyle et al., 2010). But­terflies, in par­tic­u­lar, are reared so that they or their dead bod­ies are pre­served for dec­o­ra­tive or artis­tic pur­poses (Kel­lert, 1993).

3.5. Other hob­bies: Cricket fight­ing in China (Judge & Bo­nanno, 2008).

4. Cloth­ing and accessories

In­ver­te­brates are also used to pro­duce silk (silk­worms), pearls, and shells (mol­lusks). The best-known silk is ob­tained from the co­coons of the lar­vae of the mulberry silk­worm Bom­byx mori reared in cap­tivity (ser­i­cul­ture). Around 168,333 tonnes of raw silk were pro­duced in 2014 (FAO, 2019). There are no offi­cial es­ti­mates of how many worms were used to pro­duce that amount silk. Bar­wick (2015), us­ing figures pro­vided by the In­ter­na­tional Ser­i­cul­ture Com­mis­sion, es­ti­mates that be­tween 703 billion (703,014,400,000) and over 2 trillion (2,391,686,944,000) worms were kil­led for silk pro­duc­tion in 2013.

Pearls, for their part, are pro­duced within the soft tis­sue (the man­tle) of a liv­ing shel­led mol­lusk. They are formed nat­u­rally when a par­a­sitic larva or a for­eign par­ti­cle (e.g., a small piece of rock or a grain of sand) pen­e­trates and ir­ri­tates the oys­ter, mus­sel, or clam. As a defense mechanism, the mol­lusk se­cretes a fluid to coat the ir­ri­tant. Layer upon layer of this coat­ing, called ‘nacre’, is de­posited around the par­ti­cle to form a pearl (Ellis & Haws, 1999). Cul­ti­vated pearls un­dergo the same pro­cess. But in this case, the ir­ri­tant is a sur­gi­cally im­planted bead or piece of shell called ‘mother of pearl,’ pro­duc­ing a reg­u­lar round pearl. Ad­di­tion­ally, for pro­duc­ing ar­tifi­cial pearls, mus­sels, and other mol­lusks must also be har­vested from the wild (Ellis & Haws, 1999; Gerv­ins & Sims, 1992; Pollo & Vi­tale, 2019).

Nat­u­ral pearls are ex­tremely rare. Thus, most of the com­mer­cial­ized pearls are cul­ti­vated. Ac­cord­ing to Gerv­ins and Sims, (1992), the ma­jor pro­duc­ers of cul­tured pearls have tra­di­tion­ally been Ja­pan and Aus­tralia. How­ever, other sources state that cur­rently, China is the pri­mary pro­ducer of ar­tifi­cial pearls. It is es­ti­mated that China ac­counts for about 95% of world pearl pro­duc­tion, with ap­prox­i­mately 1,600 tons of pearls put on the mar­ket ev­ery year Pollo & Vi­tale, 2019; Sus­tain­able Pearls, 2012).

5. Cos­met­ics, medici­nal ther­apy, and others

5.1. Snail slime: Snail slime is used in skin­care prod­ucts. It is com­mer­cially ob­tained from the com­mon gar­den snail species Helix as­persa (Tsout­sos et al., 2009). This is­sue is ad­dressed in an up­com­ing re­port by Re­think Pri­ori­ties.

5.2. Blowflies for clean­ing wounds: Mag­gots of blowflies (fam­ily Cal­liphori­dae) are used for clean­ing necrotic flesh from open wounds, re­leas­ing an­tibiotics and pro­mot­ing heal­ing. Th­ese an­i­mals have been em­ployed for this pur­pose since the Mid­dle Ages and now they are be­ing used on an in­dus­trial scale (Bop­pré & Vane-Wright, 2019).

5.3. Mother-of-pearl cream: Mother-of-pearl (also known as nacre) is a ma­te­rial pro­duced by some mol­lusks as an in­ner shell layer. Given its re­gen­er­a­tive prop­er­ties it is used for mak­ing skin care creams.

5.4. Shel­lac: Shel­lac is an ole­o­resin se­creted by the fe­male lac bug (Ker­ria lacca) on trees (Ra­man, 2014). Once it is pro­cessed, it is used as a brush-on col­orant, food and phar­ma­ceu­ti­cal glaze, wood finish and for long-last­ing man­icures (shel­lac nails). Between 50,000 and 300,000 lac bugs are re­quired to pro­duce 1 kg of shel­lac (To­masik, 2017c).

6. Con­ser­va­tion purposes

In­ver­te­brates of sev­eral en­dan­gered species are raised in or­der to be re­leased in the wild in rein­tro­duc­tion and re­stock­ing pro­grams. One ex­am­ple is the North Amer­i­can monarch but­terfly (Danaus plex­ip­pus) in the United States (Monarch Joint Ven­ture, n.d.). How­ever, even for con­ser­va­tion pur­poses, re­search sug­gests that these cap­tive-raised but­terflies may have lost the abil­ity to mi­grate, and they may even dis­rupt wild mi­gra­tions (Tenger-Trolan­der et al., 2019). More re­cently, some eco­nom­i­cally rele­vant species such as lob­sters are reared for re­stock­ing pur­poses to re­plen­ish overfished ar­eas (Agnalt, 2008; Hor­vath et al., 2013).

7. Warfare

For thou­sands of years in­sects have been em­ployed in hu­man con­flicts, with the aim of in­flict­ing pain, de­stroy­ing food, and trans­mit­ting pathogens. His­tor­i­cally, for ex­am­ple, sting­ing in­sects (e.g. wasps) were fired into en­emy strongholds. Nowa­days, in­sects could be back into the realm of war­fare, es­pe­cially in non­in­dus­tri­al­ized re­gions. The Na­tional Re­search Coun­cil (2003) re­ports the pos­si­bil­ity of us­ing in­sects as bioter­ror­ist weapons by re­leas­ing car­ry­ing-dis­eases in­sects or in­sects that could dam­age agri­cul­ture (Lock­wood, 2011). In the United States, gov­ern­ment re­search into biolog­i­cal weapons was banned in 1969, but re­search into pro­tect­ing U.S. mil­i­tary per­son­nel from such agents may have con­tinued, ac­cord­ing to a re­cent amend­ment. Given these sus­pi­cions, the US House of Rep­re­sen­ta­tives re­quired the US Defence Depart­ment’s in­spec­tor gen­eral to in­ves­ti­gate whether biolog­i­cal war­fare tests in­volv­ing ticks and other in­sects took place over a 25-year pe­riod (Don­nelly, 2019).

To sum­ma­rize, the fol­low­ing table (fig. 2) lists the differ­ent ways in­ver­te­brates are used, as pre­sented above:

Fig. 2. Differ­ent ways in which in­ver­te­brates are used.

Ex­cept for the figures already men­tioned above, the num­bers of an­i­mals in­volved in these prac­tices is gen­er­ally not known. Typ­i­cally, when statis­tics on the vol­ume of pro­duc­tion are available, the figures mea­sure weight, not num­ber of an­i­mals. If (some) in­ver­te­brates are sen­tient, it is im­por­tant to es­ti­mate how many an­i­mals are in­volved in these in­dus­tries in or­der to more pre­cisely de­ter­mine the mag­ni­tude of the prob­lem.

Fur­ther­more, de­spite the wide­spread use of in­ver­te­brates, very limited in­for­ma­tion about their welfare was found. Some re­searchers claim that these an­i­mals are of­ten main­tained with min­i­mal care and over­sight, in con­trast to the con­cern shown to ver­te­brates (Carere et al., 2011; Hor­vath et al., 2013). Fur­ther re­search about in­ver­te­brate treat­ment in the most rele­vant ar­eas where they are used is highly needed. In a pre­vi­ous post, we sug­gested some spe­cific as­pects of cap­tivity con­di­tions that should be ad­dressed in fu­ture in­ves­ti­ga­tions.

Ad­vo­cat­ing on be­half of in­ver­te­brates un­der hu­man con­trol—at least on be­half of those for whom there is suffi­cient ev­i­dence that they are sen­tient—seems to be a highly im­por­tant cause, given its pre­sum­able scale, ne­glect­ed­ness and tractabil­ity:

  • Scale: As men­tioned above, typ­i­cally, statis­ti­cal records of the num­ber of in­ver­te­brates used in differ­ent in­dus­tries do not ex­ist. As such, the over­all num­ber of in­ver­te­brates that are em­ployed for hu­man pur­poses is not known. How­ever, given their size and the figures given by some in­dus­tries in weight, we can hy­poth­e­size, in a pre­limi­nary fash­ion, that their num­ber is ex­traor­di­nar­ily high. Likely, this figure is still small com­pared to in­ver­te­brates liv­ing in na­ture. How­ever, this num­ber is also likely to ex­ceed the to­tal sum of ver­te­brates used and kil­led by hu­mans for differ­ent pur­poses.

  • Ne­glect­ed­ness: With a few ex­cep­tions, in­ver­te­brate welfare is gen­er­ally ne­glected both within and with­out the effec­tive al­tru­ism com­mu­nity. For a dis­cus­sion of this lack of con­cern to­ward in­ver­te­brate welfare, see one of our pre­vi­ous posts.

  • Tractabil­ity: De­spite the above, we have some his­tory of mea­sures taken for the benefit of some in­ver­te­brates un­der hu­man con­trol. Broadly, in­ver­te­brate welfare was an ob­scure topic un­til in 2010 the Euro­pean Union de­cided to up­date their an­i­mal welfare leg­is­la­tion. This leg­is­la­tive up­date gen­er­ated an im­por­tant sci­en­tific and poli­ti­cal de­bate about whether crus­taceans and cephalopods are able to feel pain or not. In par­tic­u­lar, the Scien­tific Panel on An­i­mal Health and Welfare of the Euro­pean Union con­cluded that there is suffi­cient ev­i­dence to rec­og­nize that cephalopods can ex­pe­rience pain (EFSA, 2005). As a re­sult of this con­clu­sion, the Euro­pean Union opted to give cephalopods used for sci­en­tific re­search the same le­gal pro­tec­tion that was pre­vi­ously af­forded only to ver­te­brates (Direc­tive 2010/​63/​EU). Through this leg­is­la­tion, Europe set up an agency to look at is­sues such as meth­ods of cap­ture, train­ing of work­ers in cephalo­pod welfare and anes­thet­ics, far be­yond the nar­row pro­tec­tion pro­vided by gen­eral guidelines of other coun­tries (e.g., Canada) (Ponte et al., 2019).

Be­sides the Euro­pean Union and, to a lesser ex­tent, Canada, other coun­tries such as the United King­dom, Nor­way, Switzer­land, New Zealand and some states in Aus­tralia pro­tect some in­ver­te­brates (mostly, crus­taceans) used for sci­en­tific re­search and/​for hu­man con­sump­tion. For ex­am­ple and as men­tioned ear­lier, New Zealand, Switzer­land and the city of Reg­gio Emilia (Italy) have banned boiling crus­taceans al­ive (Street, 2018). In the United King­dom, Crus­tacean Com­pas­sion is ac­tively cam­paign­ing for a similar ban as well as for fur­ther pro­tec­tions un­der the An­i­mal Welfare Act 2006 (see the cam­paign). The RSPCA—the largest an­i­mal welfare char­ity in the UK—will join in these efforts (Kennedy, 2019), as it has pre­vi­ously done in Aus­tralia. Also in the UK, the Labour Party (2019) re­cently launched its ‘An­i­mal Welfare Man­i­festo’, where it calls on the Govern­ment to ex­pand the defi­ni­tion of “an­i­mal” to cover cephalo­pod and de­ca­pod crus­taceans. Such a mea­sure, ac­cord­ing to the party, “would end the prac­tice of lob­sters be­ing boiled al­ive” (the Labour Party, 2019). Similarly, the Con­ser­va­tive An­i­mal Welfare Foun­da­tion–a Bri­tish in­de­pen­dent or­ga­ni­za­tion with Con­ser­va­tive MP Pa­trons–has pro­posed to leg­is­late to recog­nise an­i­mal sen­tience, in­clud­ing cephalopods and de­capods (Con­ser­va­tive An­i­mal Welfare Foun­da­tion, 2019).

Also in Europe, in 2017, Italy’s high­est court ruled that live lob­sters and crabs must not be kept on ice in restau­rant kitchens be­cause it causes them un­jus­tifi­able suffer­ing (Nadotti, 2017; see the rul­ing here). In the United States, the Whole Foods su­per­mar­ket chain took a similar mea­sure: the com­pany dis­con­tinued the sale of live shel­lfish from its up­mar­ket stores. The su­per­mar­ket’s de­ci­sion was the re­sult of an in­quiry which con­cluded that it was un­able to en­sure the health and well-be­ing of lob­sters and soft-shel­led crabs in the store tanks be­fore be­ing bought by cus­tomers. The Safe­way su­per­mar­ket chain also stopped sel­l­ing live lob­sters be­cause of de­clin­ing de­mand (Bun­combe, 2006).

Fur­ther re­search could po­ten­tially un­cover tractable, cost-effec­tive ways to im­prove farmed in­ver­te­brate welfare. For in­stance, re­search on ex­ist­ing in­ver­te­brate welfare leg­is­la­tion and other in­sti­tu­tional de­ci­sions (like Star­bucks’ de­ci­sion about carmine) can help to iden­tify pos­i­tive mea­sures on be­half of some in­ver­te­brates that could be im­ple­mented in other re­gions.

Still, bio­chem­istry and tech­nol­ogy ap­plied to the de­vel­op­ment of plant-based shrimp, crab, and lob­ster may play a ma­jor role in dis­rupt­ing the use of these an­i­mals as food. In gen­eral, the plant-based sec­tor is in the spotlight, with boom­ing sales, and is ex­pected to con­tinue to grow. The plant-based mar­ket may reach a “tip­ping point” if it suc­ceeds in in­no­va­tion in product qual­ity and taste (Tay­lor, 2019).

Be­sides the ob­vi­ous fact that a suc­cess­ful cam­paign could spare an im­por­tant num­ber of sen­tient in­ver­te­brates from ex­treme forms of suffer­ing, I be­lieve we have other strate­gic rea­sons, in cer­tain con­texts, to con­sider ad­vo­cat­ing in be­half of farmed in­ver­te­brates (mostly cephalopods and crus­taceans) in the near fu­ture. Or, at least, there are rea­sons to think that pro­mot­ing welfare mea­sures for some in­ver­te­brates un­der hu­man con­trol is more likely to suc­ceed than those for in­ver­te­brates liv­ing in na­ture. We should con­sider that:

  • The wild an­i­mal welfare com­mu­nity, like other so­cial groups and move­ments[11], needs vic­to­ries that in­spire: No mat­ter how small, a move­ment needs to en­courage its own sup­port­ers to be­lieve in the pos­si­bil­ity of change. Cer­tainly, our short-term goals should be cho­sen con­sid­er­ing both the amount of suffer­ing in­volved and the op­por­tu­ni­ties for change. Nev­er­the­less, in the early stages of the move­ment, the lat­ter may be given more weight in or­der to choose cam­paigns that al­low for early vic­to­ries.

  • We need to build a move­ment of trained pro­fes­sion­als: In­ver­te­brates and, in gen­eral, an­i­mals liv­ing in the wild, need an ex­pert com­mu­nity of ac­tive re­searchers and ad­vo­cates to help find solu­tions and pro­mote con­cern for these an­i­mals. Tar­geted cam­paigns can help to de­velop this know-how and ex­per­tise. Ad­di­tion­ally, these ini­ti­a­tives can en­gage more peo­ple around the wild an­i­mal welfare move­ment, es­pe­cially ad­vo­cates with di­verse pro­fes­sional back­grounds whose tal­ent may flour­ish in ar­eas other than re­search. Broadly, this may have an im­pact on strength­en­ing the wild an­i­mal welfare com­mu­nity.

  • In the fu­ture, we may need to raise aware­ness: If some in­ver­te­brates are con­scious, we may need to pro­mote con­cern for their welfare. Cam­paigns on be­half of oc­to­puses or lob­sters, for ex­am­ple, may in­vite cit­i­zens/​con­sumers to think of these an­i­mals as sen­tient be­ings, and in­di­vi­d­u­als whose in­ter­ests are a le­gi­t­i­mate ob­ject of moral con­cern. Or, at least, if cruel pub­lic prac­tices are banned—such as keep­ing lob­sters and crabs al­ive on ice in restau­rants, or main­tain­ing these an­i­mals with their claws bound in over­crowded tanks in su­per­mar­kets–this may help to be­gin de­nor­mal­iz­ing speciesist at­ti­tudes to­wards these an­i­mals. In gen­eral, weak­en­ing speciesist at­ti­tudes can pave the way for the de­vel­op­ment and im­ple­men­ta­tion of more effec­tive mea­sures that can benefit in­ver­te­brates and other wild an­i­mals in the more dis­tant fu­ture.

Pre­sum­ably, un­der­stand­ing how ex­ist­ing mea­sures to pro­tect cephalopods or crus­taceans have been achieved will help de­ter­mine un­der what con­di­tions, if any, this may be pro­moted in other re­gions, and how likely it is that such con­di­tions will ob­tain.

Conclusion

Here, in the thir­teenth post of our se­ries on in­ver­te­brate welfare, we ex­plored the pos­si­bil­ities of helping in­ver­te­brates liv­ing in the wild and un­der hu­man con­trol. When available, spe­cific al­ter­na­tives to re­duce in­ver­te­brate suffer­ing have been pre­sented. In other cases, I have sug­gested is­sues that need to be fur­ther in­ves­ti­gated in or­der to bet­ter un­der­stand the prob­lem and to study fea­si­ble in­ter­ven­tion strate­gies in the fu­ture.

One fi­nal note. Even if we learned that some in­ver­te­brates are con­scious and even if we had the tech­ni­cal means to aid them, we would still have to as­cer­tain the like­li­hood that spe­cific in­ter­ven­tions will be so­cially sup­ported and adopted. This topic will be ad­dressed in an up­com­ing post.

Credits

This es­say is a pro­ject of Re­think Pri­ori­ties.

It was writ­ten by Daniela R. Wald­horn. Thanks to Eze Paez, Hol­lis Howe, Ja­son Schukraft, Kim Cud­ding­ton, Mar­cus A. Davis, Ma­tias Vazquez, Michelle Gra­ham, Peter Hur­ford, and Saulius Šimčikas for their con­tri­bu­tion.

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References

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  1. A re­cent pa­per by Groff and Ng (2019) finds that at least one the­o­ret­i­cal ar­gu­ment for claiming that suffer­ing pre­dom­i­nates in na­ture was mis­taken and that the situ­a­tion is, at pre­sent, the­o­ret­i­cally am­bigu­ous. In par­tic­u­lar, the math­e­mat­i­cal model pro­posed by the au­thors sug­gests that rates of re­pro­duc­tive failure among wild an­i­mals can ei­ther im­prove or worsen av­er­age welfare, de­pend­ing on the species. While more em­piri­cal re­search is needed, this might in­di­cate a neu­tral-to-pos­i­tive ex­is­tence for some an­i­mals in na­ture, in­clud­ing in­ver­te­brates. Even if we con­clude that in­ver­te­brate lives are already mostly pos­i­tive, that does not en­tail that in­ver­te­brate welfare should not con­cern us. In­stead, it means that it is a less im­por­tant cause than if suffer­ing was pre­dom­i­nant. In that sce­nario, there may still be ad­verse events that cause se­vere but un­nec­es­sary suffer­ing, and hence, we should work to pre­vent them or re­duce their nega­tive im­pact. Note, how­ever, that the rea­sons given in this re­spect by math­e­mat­i­cal mod­els are, at best, weak. Con­clu­sive rea­sons to en­dorse or re­ject the claim that suffer­ing pre­dom­i­nates in na­ture can only be pro­vided by em­piri­cal re­search, as the au­thors them­selves rec­og­nize. ↩︎

  2. The so-called “in­sect Ar­maged­don” has re­cently given visi­bil­ity to var­i­ous pro­pos­als by en­vi­ron­men­tal groups to pro­tect pol­li­na­tor in­sects such as bees (see e.g. War­wick, 2018). How­ever, these mea­sures do not nec­es­sar­ily fur­ther in­sect well-be­ing, but rather seek to pro­mote the growth or halt the de­cline of these in­sect pop­u­la­tions (see e.g. Bop­pré & Vane-Wright, 2019). ↩︎

  3. Similarly, marine an­i­mals are af­fected by fer­til­izer drainage to rivers and seas—in ad­di­tion to other pol­lu­tant drain­ings spe­cific to an­i­mal agri­cul­ture (Fischer & Lamey, 2018). ↩︎

  4. Some may ar­gue that we should not in­terfere in na­ture, and hence, that we should not in­ter­vene to con­trol in­sect pop­u­la­tions. Others may have good rea­sons for limit­ing in­sect pop­u­la­tion. To delve into this philo­soph­i­cal dis­cus­sion, how­ever, ex­ceeds the pur­poses of this ar­ti­cle. The rea­son­ing here pre­sented is based on the premise that in­sect pop­u­la­tions must now be con­trol­led for food pro­duc­tion and will con­tinue to be so for the fore­see­able fu­ture. With this ob­jec­tive in mind, I try to iden­tify ex­ist­ing ap­proaches or meth­ods that may be de­vel­oped in the short term and that (if in­sects are con­scious) min­i­mize the suffer­ing caused to them. ↩︎

  5. In par­tic­u­lar, in­sect re­sis­tance to in­sec­ti­cides is be­com­ing greater, be­com­ing a ma­jor prob­lem. Ad­di­tion­ally, there is in­creased pub­lic aware­ness of in­sec­ti­cides’ pol­lut­ing effects and con­cerns about their im­pact on hu­man health (Hen­drichs, 2000; Thul­lner, 1997). ↩︎

  6. Screw-worm flies feed on plants, but lay eggs in an­i­mal wounds, es­pe­cially mam­mals and, some­times, birds. The flies can de­tect a wound from a long dis­tance, and they re­lease pheromones that at­tract even more flies. Hun­dreds or thou­sands of eggs can hatch into lar­vae that bur­row into the wound, eat­ing the liv­ing tis­sue of the in­fested an­i­mal. This in­fes­ta­tion (screw­worm myi­a­sis) can be fatal if not treated (The Cen­ter for Food Se­cu­rity and Public Health, 2016). ↩︎

  7. The com­bi­na­tion of differ­ent cost-effec­tive meth­ods to con­trol pest pop­u­la­tions usu­ally re­ceives the name of In­te­grated Pest Man­age­ment (IPM) or In­te­grated Pest Con­trol (IPC). Ac­cord­ing to FAO (2019a), IPM is “the care­ful con­sid­er­a­tion of all available pest con­trol tech­niques and sub­se­quent in­te­gra­tion of ap­pro­pri­ate mea­sures that dis­cour­age the de­vel­op­ment of pest pop­u­la­tions and keep pes­ti­cides and other in­ter­ven­tions to lev­els that are eco­nom­i­cally jus­tified and re­duce or min­i­mize risks to hu­man health and the en­vi­ron­ment. IPM em­pha­sizes the growth of a healthy crop with the least pos­si­ble dis­rup­tion to agro-ecosys­tems and en­courages nat­u­ral pest con­trol mechanisms.” It is char­ac­ter­ized as a flex­ible ap­proach to man­ag­ing pests, be­low eco­nom­i­cally dam­ag­ing lev­els. ↩︎

  8. In this talk from EA Global 2018: Lon­don, Ni­cole Rawl­ing (the Good Food In­sti­tute), Nick Rousseau (the Woven Net­work), and Kyle Fish (Tufts Univer­sity) offer their vary­ing per­spec­tives about the role, if any, that in­sects should play in the fu­ture of agri­cul­ture. ↩︎

  9. Pa­ram­e­ters: Live­stock Pri­mary; World + (To­tal); Pro­duc­tion quan­tity; Snails, not sea; 2016. ↩︎

  10. Pa­ram­e­ters: Live An­i­mals, World + (To­tal), Bee­hives, Stocks, 2017. ↩︎

  11. I as­sume that in­ver­te­brate welfare is a con­cern of the wild an­i­mal welfare move­ment. Or, when think­ing of farmed in­ver­te­brates, it may lead to strate­gic con­ver­gences with the farmed an­i­mals move­ment. Broadly, I do not en­vi­sion ‘in­ver­te­brate welfare’ as a move­ment in it­self. ↩︎