Ranitomeya
Well-known member
By the time there are cocoons on the caterpillar, the parasitic wasp larvae have already finished feeding and the caterpillar is likely not going to survive to adulthood. They chew their way out of the caterpillar, spin their cocoons so that they can pupate, and then eclose as adults. There are actually parasitic wasps that will lay eggs into the cocoons of the parasitic wasps that fed on the caterpillar in order to complete their own life cycle--I wouldn't be surprised if you noticed that something other than the wasp you expected to emerge came out of a few of those cocoons.
Caterpillars are also important as a food source for a wide variety of organisms and one of the reasons why some types of caterpillars have become such pests is because we have either introduced them to an area where there are no insectivores that are specialized at feeding on them or because we've eliminated or severely decreased the population of insectivores. We've also helped them break out of equilibrium by planting huge fields of plants and created monocultures that give rise to abnormally high populations of herbivores that feed on those plants.
Caterpillars cause billions of agricultural damage a year, with only a few that are beneficial. Even though they grow into butterflies and moths which pollinate they do FAR more harm than good.
http://www.plumasnews.com/index.php/12840-caterpillar-invasion-sparks-wildfire-worries-for-plumas-residents#!/ccomment-comment356
Caterpillars are not pests as long as there is equilibrium. Think of caterpillars and all other herbivores as nature's way of controlling plant populations and maintaining a more diverse population of flora. If any one type of plant gets out of control and takes over an area, the population of the butterfly and caterpillar that uses that plant as a host increases and lowers the population of that plant and helps other plants get the chance to return. This helps prevent certain plants from taking over and completely outcompeting others. The butterfly and caterpillar's population itself would be controlled by predators and the availability of the plant. As they decrease the population of host plants, their own populations naturally decrease--otherwise both populations become eliminated. In my mind, a pest is an organism whose services we fail to fully acknowledge or an organism that does more harm than good to the ecosystem.I think I could just as easily accept silkworms as the sole non-pest as I could dismiss them outright since they can only exist in captivity. If they are dismissed, I think all caterpillars are pests. Or put another way, all caterpillars that can even possibly live in the wild are pests. The examples above I see as examples of where their damage is lower than "normal" because their population is under control, but their behavior is still pest-like.
Caterpillars are also important as a food source for a wide variety of organisms and one of the reasons why some types of caterpillars have become such pests is because we have either introduced them to an area where there are no insectivores that are specialized at feeding on them or because we've eliminated or severely decreased the population of insectivores. We've also helped them break out of equilibrium by planting huge fields of plants and created monocultures that give rise to abnormally high populations of herbivores that feed on those plants.