Several readers have called my attention to yet another amazing case of mimicry, this time in a tephritid fly (the “true” fruit flies). Most people became alerted to this by a semi-viral tw**t by Ziya Tong, which notes that “Goniurellia tridens is a 3-in-1 insect,” and that the photo below was taken by Peter Roosenschoon in Dubai. Roosenschoon is a conservation officer at the Dubai Desert Conservation Reserve.
Those aren’t ants bedecking the fly’s wings; they’re the normal wing markings of this species. But why would a fly have antlike markings on its wing? [UPDATE: Note comments at bottom where an ant expert and two others (including Matthew) think that these are spiderlike markings. I’m coming around to that point of view.]
The issue is discussed in a New York Times‘s “Dot Earth” column by Andrew Revkin, which refers back to the original article in the original article by Anna Zacharias in The National, a United Arab Emirates newspaper. Zacharias describes it:
The image on the wing is absolutely perfect,” says Dr Brigitte Howarth, the fly specialist at Zayed University who first discovered G tridens in the UAE. [JAC: the species has been known since 1910, and is found in the Near and Middle East, Asia, and Asia.]
. . .In the UAE alone, 27 picture wing species are known. Some have wings bearing simple shapes but others, like G tridens, are far more complex.
Dr Howarth first saw G tridens on an oleander shrub in northern Oman. “I was looking at the stem of the leaves and I noticed that there were some insects crawling around. When I sort of honed in I started to notice what I thought was a couple of ants moving around.”
At first she suspected an infestation on the fly’s wings. “But it was so symmetrical that I thought, ‘oh this is not possible’. When I got it under the microscope I realised that these were insects painted onto the wings.”
In contrast to its wings and brilliant green eyes, the fly’s body is a dull greenish grey – “almost cryptically coloured,” says Dr Howarth – that blends into the leaves where it is found
Here’s a photo (uncredited) of a pinned specimen from The National:
But why the ant markings? Howarth, interviewed by Zacharias, explains:
When threatened, the fly flashes its wings to give the appearance of ants walking back and forth. The predator gets confused and the fly zips off.
That doesn’t make a lot of sense to me. Why doesn’t the fly just “zip off” by flying away when it sees a predator? Confusing a predator by waving your wings just wastes time. Now some tephritids have spider-like markings on them, and that makes more sense. Apparently the predator is a jumping spider, and when it sneaks up on a fly, it sees the spider markings, mistakes them for another spider of its species, and displays to it. That display gives away the spider’s presence, allowing the fly to get away. But I can’t see this happening with ants."
https://whyevolutionistrue.wordpress.com...mic-wings/
Those aren’t ants bedecking the fly’s wings; they’re the normal wing markings of this species. But why would a fly have antlike markings on its wing? [UPDATE: Note comments at bottom where an ant expert and two others (including Matthew) think that these are spiderlike markings. I’m coming around to that point of view.]
The issue is discussed in a New York Times‘s “Dot Earth” column by Andrew Revkin, which refers back to the original article in the original article by Anna Zacharias in The National, a United Arab Emirates newspaper. Zacharias describes it:
The image on the wing is absolutely perfect,” says Dr Brigitte Howarth, the fly specialist at Zayed University who first discovered G tridens in the UAE. [JAC: the species has been known since 1910, and is found in the Near and Middle East, Asia, and Asia.]
. . .In the UAE alone, 27 picture wing species are known. Some have wings bearing simple shapes but others, like G tridens, are far more complex.
Dr Howarth first saw G tridens on an oleander shrub in northern Oman. “I was looking at the stem of the leaves and I noticed that there were some insects crawling around. When I sort of honed in I started to notice what I thought was a couple of ants moving around.”
At first she suspected an infestation on the fly’s wings. “But it was so symmetrical that I thought, ‘oh this is not possible’. When I got it under the microscope I realised that these were insects painted onto the wings.”
In contrast to its wings and brilliant green eyes, the fly’s body is a dull greenish grey – “almost cryptically coloured,” says Dr Howarth – that blends into the leaves where it is found
Here’s a photo (uncredited) of a pinned specimen from The National:
But why the ant markings? Howarth, interviewed by Zacharias, explains:
When threatened, the fly flashes its wings to give the appearance of ants walking back and forth. The predator gets confused and the fly zips off.
That doesn’t make a lot of sense to me. Why doesn’t the fly just “zip off” by flying away when it sees a predator? Confusing a predator by waving your wings just wastes time. Now some tephritids have spider-like markings on them, and that makes more sense. Apparently the predator is a jumping spider, and when it sneaks up on a fly, it sees the spider markings, mistakes them for another spider of its species, and displays to it. That display gives away the spider’s presence, allowing the fly to get away. But I can’t see this happening with ants."
https://whyevolutionistrue.wordpress.com...mic-wings/