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Interesting Photo Finds: Parastic Flies or Strange Mouthparts?

Updated: Sep 7, 2023

I am reviving this series because I had a great deal of fun doing it. Today I will be posting an image I took in Papua New Guinea.

During ant course, I spent relatively little time observing Anonychomyrma, primarily because their scent was overwhelming even amongst dead workers. But upon selecting the best photos I had taken of a colony I encountered this exciting picture which seemingly depicted a parasitic fly emerging from the mouth of an individual.

The fly can be seen on the individual to the right.

This observation was made from a nest of Anonychomyrma sp. in Baitabag, Papua New Guinea during the ant course. Anonychomyrma of course means "Ant Lacking Claws" (clear sarcasm I hope, I had no idea the derivation of this name and searched the internet to no avail and finally had to ask chat GPT which is actually somewhat reliable on matters of word roots and meanings). Setting aside the unfortunately long and difficult-to-pronounce name, Anonychomyrma is actually quite an interesting genus. It was (as a matter of fact) described from Papua New Guinea, in 1947 by Horace St. John Kelly Donisthorpe. The irony is not lost on me that Donisthorpe had a name that is about as unfortunately long as his Anonychomyrma. Apparently, Donisthorpe is engaging in his own right and is memorable in part for his prolonged support in a taxonomic dispute which led some scientists to rename Lasius after him as Donisthorpea. He attempted to describe some 400 species of ants; and only about half of these were valid. In this regard, some were critical of just taxonomic work for over-splitting many taxa(2,4). One of those 6 valid extant species was Anonychomyrma myrmex, its type from Papua New Guinea.

The genus Anonychomyrma is interesting in its own right. In PNG, they were found across many species of symbiotic ant plants, which have hollowed structures that develop in the plant for the ants to nest in. They also (similar to Philidris and Pseudolasius) form soil tubes on the surfaces of the plants to move around the surfaces of the plant without being disturbed. I cannot remember if they tended to leafhoppers on the outside of the plants, but they certainly tend to hemipterans within the actual stems or body of the ant-plant. This is what 'makes up' for the fact that the plants don't have extrafloral nectaries. The plant benefits in a number of ways, The ants excrete waste which helps fertilize the plants, but it primarily receives effective protection from various external predators and pests.

An Anonychomyrma colony effectively deals with a scorpion that has stepped foot on their nest tree.

I find Anonychomyrma interesting for another reason. The center of their diversity is in Papua New Guinea, where there are 14 described species (I think more species are waiting to be described). In PNG they appear to be quite dominant in the canopy. In this regard, I find them quite analogous to the Neotropical Azteca in habitat, appearance, and biology. Anonychomyrma even shares a similar queen shape to Azteca with that strange flattened angled profile that is characteristic of arboreal ants like Azteca.

An Anoychomyrma queen from an online Tanzanian insect field guide.

An Azteca queen image taken by Alex Wild in Panama.

But the reason anyone would notice Anonychomyrma would likely not be any of the interesting points of biology (besides possibly being quite dominant), it would be that they excrete an overpoweringly potent smell of blue cheese. This trait, while not restricted to Anonychomyrma is one of the most recognizable tenants of the subfamily they are a part of. Although I would venture to say (based mostly on experience with a few genera) that every genus in Dolichoderinae has a slightly different smell that can be united under that 'blue cheese' description if it is the first provided.

I guarantee that when taking this photo, I was thinking about buffalo wings and blue cheese dressing (A).

The Interesting Photo Find.

Moving onwards to the actual photo, since I noticed that I got distracted researching Anonychomyrma.

As we were heading back from one of our field trips to Baitabag, I was going through my photos and selecting ones to save and export later. This is my normal procedure, as I want to highlight the photos in the best focus and give them a 3-star rating. Then later in my editing process, I apply a 2-5 star rating as needed to sort further. As a part of this procedure, I always zoom in as much as my camera's digital zoom allows and investigate individual workers in focus in the photo. That is when I noticed this worker's mouth...

With absolutely no measure of certainty, I wondered if this was possibly a phorid fly, like those made famous for their use in biocontrol against fire ants. These flies (of which there are a number of species) are also quite fascinating because of their biology. They are mainly parasites of ants (and other hymenopterans) which lay eggs at the base of the head capsule of their host. When the egg hatches the larvae crawl into the head and feed on the hemolymph and eventually cause the head to detach. Then they emerge through the front of the ant where the mouthparts would normally be.

There are 2 main reasons I am still very much uncertain as to what we are looking at. 1) The head is still on the ant, whereas a phorid fly would likely decapitate it. 2) The ant appears to still have its palps, and I would expect it to lose them if a fly was emerging from its face. It was on these grounds that Phil Ward agreed with me that it was likely not a fly. A third reason against the designation of phorid fly exists, 3) the 'fly' has a differently shaped head which is much smaller than what a phorid fly would likely look like. It is still possible that this is a fly (or maybe even a wasp?), but probably not a phorid fly. The evidence supporting the fact that this may be a fly (beyond the fact that it appears as such) is that none of the other workers display mouthparts this long. If argument number 2 had any reason to be refuted, it would be that I can't tell if those are palps, antennae, or legs of some sort. If it were any of the legs or antennae, this would be a parasitic fly rather than an ant labium.

Phorid flies normally pop off their victim's head capsule and emerge through the mouth. Photo by Sanford Porter.

The fact of the matter is that this photo was taken with a large focus area, and so zooming in reveals a quite fuzzy, confusing image that cannot be made out fully. If this is a parasitic fly, this photo is very interesting, if it is not, the photo is still interesting to look at and ponder on why the mouthparts look like that. I guess the only way to know with more certainty is if someone at the BRC was to find a parasitic fly similar to the 'parasitic fly' that I photographed. (B) Otherwise, it is probably more responsible to assume that this is not a fly, but rather a raisin...


(4) A fundamental error on my behalf was not to verify antwiki with antcat. Big thanks to Benjamin Palmer for pointing this out to me on Twitter! After he notified me, I altered the article slightly to be more accurate, whilst attempting to maintain the original meaning and form. So here I include the link to donisinthorpes contributions to taxonomy:

Here's the story on donisinthorpea as informed by Benjamin Palmer who told me about this:

The genus Donisthorpea was not described by Donisthorpe himself, but by Morice & Durrant (1915) in possibly one of the most controversial taxonomic publication thus far. They pointed out that the genus name Lasius had already been used for a bee genus described by Jurine in 1801, and that the ant genus we know today, Lasius Fabricius, 1804, was thus a homonym. A long debate followed, in which almost every myrmecologist of the time had his own opinion and many different names were proposed. The genus Donisthorpea was hardly recognized by anyone except Donisthorpe (even Morice & Durrant corrected themselves in 1917). The debates dragged on until 1935, when the ICZN officially declared Jurine's publication invalid, making Lasius Fabricius, 1804 available again. This decision was accepted by all renowned myrmecologists, except one: Donistorphe continued to use the name Donisthorpea until his death in 1951. (Benjamin Palmer, Pers. Com., 2021)

Trivia/Regional References

I'm hoping that some of my audience (potentially other course participants...) from outside the US read this article, so I am including these here for clarity, and also because I want to rant about Buffalo sauce.

(A) 'Buffalo wings' has nothing to do with buffalo, instead, it refers to a sauce flavor applied to fried chicken wings. The wonderful internet tells me that buffalo sauce is made with a mixture of hot sauce, butter, vinegar, and Worcestershire sauce. It is often enjoyed with Blue cheese sauce. It has nothing to do with buffalos and is generally not even applied to wings, but rather often applied to drumsticks or other parts of a chicken. So I really don't understand why we call it Buffalo Sauce or Buffalo Wings. I would honestly assume a buffalo sauce would taste something like a barbeque sauce. It also does not go well with bison meat so it is not aptly named. (I looked it up, they are from Buffalo, New York, The naming scheme now makes sense but I am incredibly disappointed nonetheless)

(B) The term "It is not a fly, but rather a raisin" comes from an episode of Phineas and Ferb where Doofenshmirtz tries to convince his waiter that there is a fly in his soup (TV troupe) but is instead told that it is a raisin. In the episode, he takes the 'raisin' to an entomologist who confirms that it is indeed a raisin, but that on the other side, it is a fly.

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