Tuesday, May 08, 2012

Poop Flinging and Other Poop Strategies

Caterpillar shelter
Many insects eat rather non nutritious plant parts. So they need to consume large amounts, extract the nourishment, such as proteins, and discard the rest at the other end. In simpler words: they eat a lot and poop a lot, or if you prefer, they produce large amounts of frass or waste material.
Wasps are some of the worst enemies of caterpillars. They are constantly seeking them to feed their young. Many wasps are superb at controlling insect pests. I would think twice before hurting one of them; they are our friends. Without them, there would be population explosions of plant-eating caterpillars.

Leaf-roller caterpillar and its frass
Caterpillars have devised different ways to hide and keep these ferocious predators from finding them. The so-called leaf-rollers fold a leaf, stitch it together with their silk and stay inside the little tunnel munching away in relative safety. The amount of frass that accumulates inside these little shelters can be impressive. One wonders how they can live in such conditions. Not pretty!

Tiny black dots of frass hurled by caterpillar
Unfortunately for the caterpillar, the smell of their poop is an excellent clue to their presence. You may say that predatory and parasitic wasps have a nose for food-related aromas. So, certain caterpillars have developed a singular strategy. They throw their waste material as far as they can; which can be pretty far. Eight to twelve inches for a caterpillar not much bigger than a grain of rice! That is as if you could throw the you-know-what several yards away.

The curious thing is that many moths and butterflies belonging to different families have come up with the same poop-flinging solution to hide from predators. Among them there is a skipper that you may probably have seen visiting flowers, the silver spotted skipper. It gets its name from the brilliant spot on its hind wings. When this skipper was a caterpillar it regularly shot cannon balls of its own frass as far as a couple of yards away. How about that!
Silver-spotted skipper

Orchard Swallowtail caterpillar 3148
Bird-dropping caterpillar
(by Malcom NQ, Flickr)
Another poop strategy of sorts is that used by many caterpillars called bird-dropping caterpillars. Their appearance, as the name tells you, resembles a bird dropping. Apparently the ruse is convincing enough to discourage would be predators. No real poop is involved here, but it is worth mentioning in an article about poop strategies.

Leaf beetle larva hiding under its poop
And then, there are other insects, particularly a group of leaf beetles that have turned things around completely. Instead of leaving their poop behind, they proudly carry it around as a shield. Some build a sort of basket or nest above and around them. Others have a projection shaped like a coat rack, from which they hang their byproducts, castoff skin and poop. You can read more about one of them in The Poop Bug and the Golden Beetle

More on frass strategies
List of articles 

© Beatriz Moisset. 2012

1 comment:

Sunnyside Dru said...