Do you think it would be different for detritivores compared with herbivores? Given that many plants aren’t significantly consumed by animals, it seems there is often food in existence for herbivores to eat. In contrast, almost all decomposing organic matter will eventually be eaten by someone or other, so that food source could run out (or, if food doesn’t run out, then maybe water does during dry periods). That said, maybe insect decomposers are still limited in number by factors like predators and parasitoids, and it’s the other decomposers (bacteria, fungi, etc) who mainly face the resource limits.
I think its going to differ between species groups and habitats within the classification of detritivore. The fact that plants are not significantly consumed by terrestrial herbivore suggests that there is lots of dead and decaying material about for terrestrial detritivores. Moreover, the plants keep producing more, so its not like it runs out (at least not unless there is a major perturbation). Of course there are issues like C:N ratios but most (all?) detritivores consume microbes and fungi as part of their diet as well. The situation may be different for species that focus on other resources (dung beetles), and certainly in aquatic systems there is often no significant standing stock of primary producers, so there could be limitations there (e.g., studies on stream leaf shredders often point this way), although in open pelagic systems the “standing stock” is really secondary production, and that is what detritivores would focus on.
Where would starvation fall under in the juvenile mortality pie chart? Or is that something r-selected species don’t typically go through.
It would be under competition in the pie chart. It is a lowish percent of total mortality.
Do you think it would be different for detritivores compared with herbivores? Given that many plants aren’t significantly consumed by animals, it seems there is often food in existence for herbivores to eat. In contrast, almost all decomposing organic matter will eventually be eaten by someone or other, so that food source could run out (or, if food doesn’t run out, then maybe water does during dry periods). That said, maybe insect decomposers are still limited in number by factors like predators and parasitoids, and it’s the other decomposers (bacteria, fungi, etc) who mainly face the resource limits.
I think its going to differ between species groups and habitats within the classification of detritivore. The fact that plants are not significantly consumed by terrestrial herbivore suggests that there is lots of dead and decaying material about for terrestrial detritivores. Moreover, the plants keep producing more, so its not like it runs out (at least not unless there is a major perturbation). Of course there are issues like C:N ratios but most (all?) detritivores consume microbes and fungi as part of their diet as well. The situation may be different for species that focus on other resources (dung beetles), and certainly in aquatic systems there is often no significant standing stock of primary producers, so there could be limitations there (e.g., studies on stream leaf shredders often point this way), although in open pelagic systems the “standing stock” is really secondary production, and that is what detritivores would focus on.