Hey ^^ Not sure if this is the place to ask but I’ve been wondering something so I thought I’d share here. I’ve recently noticed that some crambid snout moths I’ve spotted sit in an odd position while resting. Not all of them do this, like this elegant grass-veneer had nothing unusual about it, yet this mottled grass-veneer positioned itself like a playful dog and just stayed like that for quite some time. This clearly isn’t unique to mottleds, as this bluegrass webworm moth, this changeable grass-veneer , and many others I’ve seen around iNat are doing it as well!
Despite this clearly not being an uncommon sight, I can’t seem to find any explanation for it anywhere. Is this a breeding-related behavior? Is there something about their body structure that makes resting this way more comfortable to them? Is it even known why they do this? Maybe it’s an silly thing to question but it makes me giggle every time I see it and I’m just curious as to what the point of it is.
There are, as you noted, quite a few Crambids that do this. There’s also a number of moths that do the reverse, where they’re propped up high on their front legs. Caloptilia are good examples of this, and I think some of the Crambids do so as well. I would guess, given that these are resting positions, that camouflage is driving it. (When you spot them near lights, they’re not choosing their normal sort of resting spots, so the camouflage doesn’t really work…)
Agreed on camouflage. I think that when they strike this pose in vegetation, they appear like a broken twig. Like psweet says, when they do it on a moth sheet or something else, it looks funny, but it has a purpose in other contexts.
Agreed it’s probably camouflage: Though that doesn’t explain the photos of my sleeping in the same pose as a toddler. Perhaps it’s just pan-species all-ages yoga?
Apart from their resting posture, we may compare their feeding/mating posture with the resting posture, so as to verify the reason of camofledging. Me personally haven’t yet observed crambid moths except in resting postures though.
As a general comment the resting posture is one of the many clues you have in the field to identify a moth to say family level, if you combine that with other clues such as size, antennae shape, where the antennae rests, shape of wings etc. And always be on the lookout for exceptions, where there likely will be many.
With slug moths, you can frequently tell sex by these postures. At lights, you will generally see the males arrive first and exhibit an interesting posture with their abdomen curled up through their wings. After a couple hours, the females show up in far fewer numbers, but keep their bodies straight. Some males don’t curl though, so it isn’t perfectly reliable.