Reader Tony Eales from Oz sent us some mimics; his words are indented. (See yesterday’s post on mantid flies.)
I photographed a couple of wild mimics yesterday. First was a large Mantis Fly, Euclimacia nuchalis, mimicking a large brown paper-wasp similar to this wasp.
Here’s the fly:
And the wasp (not Tony’s photo):
Also yet another ant-mimicking Jumping Spider (Myrmarachne sp.). I can’t stop photographing these.
But the weirdest was a jumping spider, Abracadabrella elegans, that mimics a fly’s face with its butt. It even runs backwards at times. I can’t for the life of me figure out why this mimicry occurs and all the sources are very hand-wavy about it.
The spider’s butt definitely resembles a fly, and this is likely a case of mimicry. But why???
Amazing mimicry, very cool!
Is it mimicking a fly or a velvet ant?
The local Velvet Ants don’t look like that. To my eye it most closely resembles a robber fly face. The stripes (if you imagine the spider laid straight) might represent wings. what’s odd is that this is often under bark so what use is the mimicry there?
Neat! Your mantidfly is similar to one I see around here, but I think yours is larger.
Odd too to mimic a fly face while the rest is cryptic. Commencing handwaving: Maybe to sneak up on unsuspecting insects? End handwaving.
My guess as to the fly head butt is “wolf in sheep’s clothing” camo.
“The spider’s butt definitely resembles a fly, and this is likely a case of mimicry. But why???”
I know near nothing about fly and spider relationship but I propose a hypothesis: if a fly want to copulate with the false fly, it will go to the fanged side of the spider (i.e., the putative back of the false fly).
That… is brilliant. I like it! And it is testable.
An alternative (and less sexy) hypothesis is that fly predators (small birds) would try to cut off a fly’s escape by attacking from the head, or anticipate it fleeing “head” first, thus giving the spider the advantage of surprise when jumping in the opposite direction.
A third hypothesis for an adaptive advantage is that birds that prey on small spiders (and many of them do) but which learn to avoid wary, difficult-to-catch flies would tend to ignore fly-mimicking spiders as a waste of time.
These two hypothesis are not mutually exclusive.
I wonder if it’s to put off wasps that parasitise spiders but not flies.
Damn but that works for me!
As an explaination, not something I actually do.
Likewise, i am no expert but this, the mating hypothisis would restrict the diet to the mimic fly species only would it not? nutritionally inhibiting itself and until a “mate” comes along. Pheromones might be at play and mating behaviours so it would have to be more going on than just carrying a fly head around on your butt….
Stealth by fly look alike might be more productive over a range of prey, approach then it gets tricky but not beyond these little creatures.
Mimicry + arthropods! Great pics!