What goes in, must come out. While all animals live by this law of digestion, there is one group whose evacuations now have my attention.
It is frass season.
Frass is the name for the excrement of insects. Liquid, solid or somewhere in between describes all nature of extrusions that seem to be exploding all over the ground, trails, bike paths, driveways and roads. Consider all of the caterpillars crunching, insects ingesting, moths munching, earwigs eating and beetles perhaps even belching!
Voiding is done with finesse and without kidneys. While vertebrate animals have kidneys to remove their waste, most insects have outgrowths of their digestive tracks, called Malpighian tubes, for their waste management.
While we try to flush it down as fast as we can, a selection of insects keep theirs handy and have an interesting array of uses for their frass. Some caterpillars will attach it to the midribs or terminal end of leaves to extend the leaf. It is thought that this will keep predators away.
Another form of protection is afforded by frass: three-lined potato beetles spread their wealth on their back as a poop shield of sorts. Since they eat nightshade plants that contain toxins, their excrement maintains the poison so that predators won’t eat them.
A more active answer to predator deterrence is practiced by other species of caterpillars that actually throw or fling their wastes using their body or a structure called the anal comb or fecifork. This activity, aptly named faecal firing, provides security since predators often tail caterpillars by the smell of their feces. By scattering it, those predators may not be able to find their prey.
Another insect dropping drama occurs in certain beetles. Instead of scattering their scat, they collect and covet it. Some species use it for food. In one case, the larvae of bess beetles eat excrement because their jaws aren’t strong enough to handle their fibrous wood foodstuff. As adults, these beetles continue to consume their droppings because they need to keep up the number of microbes in their guts.
Termites have some similarities to those beetles. They aren’t born with the gut microbes necessary to consume their food, so they eat feces from adult termites (sometimes directly from the source) to get those microbes. This is called anal trophallaxis and gives new meaning to the phrase “waste not, want not!”
If food isn’t reason enough to desire their dropping then how about housing? Termites can sanitize and reuse it as construction material.
Not all insects, however, embrace their waste. Cockroaches gather and remove it from their nest and some beetles store it in unused tunnels. Leaf cutter ants have a pecking order and at the bottom of it are those whose only job is to clean up and remove frass.
In a nightmare scenario for those of us that simply can’t wait are bees, which sometimes have to wait quite a long time to go. As they overwinter, and since they won’t void where they live, bees may have to wait for weeks for a restroom opportunity. And newly hatched bees hold their wastes in their bodies in a giant pellet called a meconium until the weather is nice enough for a purging flight.
Insect efforts at cycling, recycling and re-recycling are quite admirable, and due to their great numbers provide a septic solution we can envy. Perhaps we can learn to look at their waste now with more appreciation, rather than see them as I previously did — as simply just a pain in the frass!
Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature.
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