Trichaeta pterophorina – Borakalalo National Park, South Africa
Another photo from the South Africa files, and one that continues the mimicry theme that has been featured in several recent posts. It’s not a great photograph – the focus is off – but the colors these moths sport are dazzling, and there is a nice symmetry to their tail-to-tail mating position.
Roy Goff, author of the website African Moths, tells me this species is the Simple Maiden (Amata simplex) in the family Arctiidae (whose ~2,000 species worldwide are increasingly considered a subfamily of the already enormous Noctuidae) [update 6/20/2012—Martin in a comment considers these moths to actually represent Trichaeta pterophorina in the same subfamily]. Its gestalt – greatly resembling a stinging wasp – brings to mind the so-called “wasp moths” of North America (subtribe Euchromiina); however, maidens belong to the exclusively Old World Syntomina. Like the wasp moths, most maidens are exceptionally colorful and exhibit clearly aposematic patterns. While these might seem to be textbook examples of Batesian mimicry, most species in this group are also protected by distasteful secondary plant compounds that they sequester through feeding, making them Mullerian rather than Batesian mimics. These compounds are not only acquired by larvae from their food plants, but also by adult moths who imbibe them from fluid regurgitated through their proboscis onto dried parts of plants containing the compounds and into which they dissolve.
Their aposematism is not limited to strictly visual cues. An Australian species, Amata annulata, is known to regularly emit ultrasonic clicks when flying, thought to be aposematic behavior to warn bats of its distastefulness in the same way that that its coloration warns daytime predators. Additional defensive characters that have been described for species in the group include frothing and extrusion of defensive processes. Clearly, maidens are leaders in the arms race among the insects!
Copyright © Ted C. MacRae 2010
Beetles In The Bush 
Soft focus, a wisp of grass, subtle background tones…a couple meet on a stem…how romantic!
Your description of how they feed (regurgitate, dissolve, imbibe) brings to mind spiders or assassin bugs, and it set me to wondering if the evolution of this trait could have ever led to a predatory moth?
I’m glad you like the “wisp of grass” – this is a slightly cropped version of the original, and I debated whether to include/exclude that grass stem. I liked it and so kept it.
I don’t know about an outright predaceous adult moth, but there is a genus of moths known as “vampire moths” that feed on vertebrate blood. These moths are thought to be derived from species that imbibe liquids from fruit.
There are also carnivorous larval lepidopterans in Hawaii that exhibit simple “grab and chew” behaviors, but a more recently discovered species, also in Hawaii, preys upon snails that it ensnares in silken webs. One of the discoverers commented, “It was like finding a wolf that dives for clams.”
Great story Ted! I’m pretty sure that there are also tiger moths in Canada (and likely the US as well) that have ultra-sonic clicking for bat defenses. I can’t remember the details as it was a while ago that I did a project on them, but I believe the North American species use it to actually disrupt the bat’s echolocation, making themselves invisible right before the bat goes to strike! Cycnia tenera appears to be the species I was thinking of according to Google Scholar.
I think for distasteful species like this one (and Cycnia tenera), it would be difficult to determine whether the clicking functions by disrupting the bat’s echolocation or by warning about the prey’s distastefulness. For the latter, the clicking pattern would have to be taxon-specific, and perhaps it could serve both functions.
Love the moth photos! That reminds me… I have a short video of an Arctiidae foaming from Costa Rica, I’ll have to get around to posting it. The best part, it smelled like peppermint and made your mouth numb (can’t blame me for trying).
Oh, I’d love to see that, and of course I’d expect nothing less from a true lepidopterist than a taste test.
The feeding behavior sounds like flies: regurgitate on something, then drink the leftovers. Or as Adrian pointed out, like spiders.
The photo has a certain artistic quality to it. Sometimes ‘technically’ perfect photos are less interesting than the relaxed feel of mistakes. Or so I think–especially since I make more mistakes than technically perfect photos!
And I love that I pick up all sorts of new information from your descriptions. Mullerian… A new concept to add to my understanding.
Thank you, Jason – high praise from a great photographer!
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Hi
Super photograph but the moths shown in the photograph are not Amata simplex but are almost certainly Trichaeta pterophorina (Mabille, 1892), in the same subfamily
Hi Martin – thanks for the correction. I guess Goff Martin now agrees they are not Amata simplex, as he has replaced this photo with (which used to be on his site) with photos of a clearly different species.