How Stick Insect Eggs Survive After Being Eaten By Birds

For the past few years stick insects have been gathering more and more attention online due to their strange appearance. Stick insects are aptly named, as they look almost exactly like sticks or twigs. As you can imagine, their stick-like appearance gives these insects the most convincing form of insect camouflage that exists. Pretty much every animal on the planet, including insects, possess bodies that are bilaterally symmetrical. Although stick insects are also technically symmetrical, some species resemble sticks to the point where they appear just as asymmetrical as any other stick or twig. Despite the fact that most stick insects have the advantage of looking like a random stick, birds still manage to eat a lot of them. In fact, stick insects are eaten so frequently that researchers don’t exactly understand how they have avoided extinction. However, researchers now believe that stick insects survive not in spite of bird predation, rather they survive because of bird predation. Although this sounds illogical, the science to back up this claim seems solid. The researchers learned that many stick insect eggs are indeed consumed by birds, just as adult stick insects are, but these eggs manage to survive the process of digestion. Eventually, birds expel the eggs as waste, which allows the still viable eggs to develop into larvae, and eventually, adults. Strangely enough, it may be birds that are preventing the extinction of stick insects.

Stick insects and some plants survive on this planet in similar ways, and in both cases their survival is all thanks to birds. Birds often eat fruit, and in doing so they swallow the seeds. Eventually these seeds are expelled onto soil where they grow into new plants. Similarly, stick insects are eaten along with their eggs. Due to the uniquely hard shell belonging to stick insect eggs, the eggs remain viable throughout the birds digestion. Most insect eggs are not as durable as stick insect eggs, as stick insect eggs are composed of calcium oxalate, which is a material that can only dissolve when exposed to highly acidic chemicals. Many researchers now believe that these hard shells evolved so that stick insects could continue to thrive. This is a rare example of an animal prey using its predator enemy to benefit its own survival.

Do you think that stick insect eggs evolved to be more durable in order to allow for the continuation of the species?