Sep 6, 2017
So, for the notes for this episode I'm going to stray a little farther afield from the actual podcast and give visual examples of how insects use color. Some of these are relevant for aquatic insects / trout fishing and some really aren't. But they are cool, so...
Probably the simplest and most intuitive use of color is camouflage. The following pic is of a cone headed katydid - which is green. Like the plants it hangs out on.
Katydids are found around streams just as much as grasshoppers (if not more so), so I've always been surprised that there aren't more katydid imitations (or green grasshopper imitation). I've fished 'em. Had luck with them, but I can't say I've compared them enough to grasshopper imitations to say that one worked better than another in any kind of situation.
Another example of that, which might be more relevant is this mayfly nymph- a Mccaffertium - which is mottled and brown like the bottom of a stream. Same idea, just not as dramatic as the katydid.
An interesting variant of that is what I've heard called "flash and dazzle" coloration. Where normally they are camouflaged - note the front wings. But when they are disturbed by a predator, the brightly colored hind wing becomes visible - with a big surprising flash.
The predator then focuses on the bright color as the insect escapes. When it lands, however, the focus point vanishes and the insect will move a bit from where it landed. The predator will focus on the landing spot and miss their meal. The same idea is practiced by cotton tail rabbit and white tailed deer.
In this picture, to the left is a common North American grasshopper - I don't know the name. And to the right is an example of a fairly common group of moths, called the underwing or Catocola moths.
In the episode, we talked about Mullerian mimicry. Below is an example of that - where multiple different species share warning coloration (such as yellow or red or orange on black). So, once you get stung once, you associate that color with danger. Works for birds as well as people. Below are all different species of genus Bombus - or bumble bees.
Batesian mimicry is when something that is harmless mimics this warning coloration. I have several examples below. First are a two different species of hawk moths - which mimic bumblebees both in looks and behavior.
While below are two robber flies which also mimic bumblebees (an example of which is in between them). The robber flies (Family Asilidae) are predatory - and use the mimicry both, I suspect, for protection, but also to approach and catch pollinating insects on the flowers where it hunts.
My favorite example, however, is the clearwing moths - which mimic wasps. Check out this picture and tell me which one is the moth.
All right, maybe it isn't that hard - it's the one in the middle. Still, I'm really impressed with these moths.
Interestingly, a scientific article just came out with a newly discovered clearwing moth from Malaysia. Here is the press release, which includes a video of the critter:
On the podcast I also mentioned irridescence. Which you can see here. I don't have a lot of examples of this in my collection because I've lost my beetles and because most examples of this are in tropical insects. But here you can see it in this tiger moth (Family Arctiidae) that I caught in Florida.
Note how you see the blue on the abdomen and one wing. It is on the other wing as well, you just need to change the perspective of your view (of the real insect) to see it.
Lastly, just for grins, in case you see on in your rambles. Here is a golden rod spider (on a copper pot rim, he came in with garden produce). They are in a group of spiders known as "crab spiders" - Family Thomisidae. I mentioned them because they have the ability to change color to match their background -from yellow to white and back again.
Lastly, this is a bit of a stretch linking it to this episode, but also just recently, an article came out discussing the visual acuity of insect sight.
So, there you go. Hope you enjoyed the episode.