5. Robber Fly Hunting Queen Ant

Subject: Underworld Robber Fly (Neoitamus orphne) and New York Carpenter Ant Queen (Camponotus novaeboracensis).

Location: Algonquin Provincial Park.

Date: July 2017.

For an Introduction to this series (my Top 20 Nature Photos of 2013-2020) go here.

The Story Behind the Shot: Every ant colony, each civilization in the soil, has to begin with a single type of individual: an ant queen*. Queens are special individuals, easily separated from the workers by their wings (at this preliminary stage) and their relatively large size. While camping in Algonquin during the summer of 2017, my campsite was in the path of dozens of queen carpenter ants. I watched as several different individuals wandered through the pine needles and discarded their wings. I had also been separately observing a large robber fly that had taken up residence on my camping table, using the surface to survey for potential prey. At some point the robber fly descended upon one of these ant queens and I was lucky enough to spot the unfortunate queen and its fortunate hunter.

*nature never lets me get away with generalizations… I would have liked to say, for the drama, that every colony begins with a single individual, but that isn’t true at all. There are many species of ants that create new colonies with multiple queens as a rule, and many times groups of workers accompany the queen (or queens). One of the most famous of these species is the Southern Fire Ant Solenopsis invicta, but dependent colony founding (that is, colonies that begin with a queen dependent on workers as opposed to independent colony founding) is widespread in ants. As in all things in the natural world, the picture becomes increasingly complicated, the more we know (Peeters and Molet 2010).

The Story Behind the Species:

Part 1: New York Carpenter Ant (Camponotus novaeboracensis):

The ant queens that I saw that day had emerged from a colony in what is termed a mating swarm. Multiple colonies in the area, triggered by the weather conditions must have swarmed at the same time, winged ants filling the air and meeting to mate. The males of these ants die soon after mating, but the queens will live for several years if they can establish a colony. The vast majority of ant queens will also die during this mating flight. Holldobler and Wilson (1990) describe this well: “It follows that the brief interval between leaving the home nest and settling into a newly constructed nest is a period of intense natural selection among queens, a dangerous odyssey that must be precisely timed and executed to succeed.” After mating, the ant queens descend to the earth and never leave it for the air again, removing their wings and absorbing the flight muscles within to provide the nutrients for their first batch of eggs. Camponotus novaeboracensis prefers nesting in dead standing trees or fallen logs or stumps, but they are occasionally found nesting under rocks or cow dung (Ellison et. al. 2012). Contrary to what you may think, carpenter ants (the genus Camponotus) don’t consume wood for food, instead carving into decayed wood in order to create a nesting site. One of their major sources of food is actually honeydew from Homoptera (true bugs such as leafhoppers, treehoppers and aphids), but they also collect sap and hunt insects and will scavenge on dead vertebrates as well (Hansen and Klotz 2005).

Foraging as an ant worker is dangerous, there are many other creatures foraging that would hunt down ant workers, and that’s ok for the colony because each worker is just one small part of a larger whole. Camponotus novaeboracensis colonies can contain almost 9000 workers (Hansen and Klotz 2005), but usually only a single egg-laying queen*. So workers can be lost, and the colony continues, but the queen is important so the colony can begin. If she is lost before she can find a nesting site, as in my observation here, there can be no colony of thousands.

*Akre et. al. 1994 report that C. novaeboracensis colonies rarely have more than one queen, but it does happen.

Part 2: Underworld Robber Fly (Neoitamus orphne):

Robber flies are incredible hunters, swooping out from perches on branches or twigs (or in this case, camping tables) to pounce upon insects and stab them with their powerful piercing mouths. There are over 7000 species of Robber Fly (members of the family Asilidae) worldwide (Marshall 2012). Neoitamus orphne has a specific name, orphne, which refers to a spirit of Greek mythology that lived with Hades in the Underworld, and is sometimes referred to by the name “Styx”. I love the idea of this fly being named after a spirit of the Underworld, as this robber fly must send many souls of insects to Hades on a frequent basis. The individual pictured is a female, which will use that long tubular abdomen to lay eggs inside flower heads or leaf sheaths. The larvae then hatch and drop to the ground, where they will hunt down soil-dwelling invertebrates presumably (Marshall 2012). I say “presumably” because I don’t think anyone knows for certain what this species of robber fly eats as larvae but robber fly larvae are predators and this genus has larvae that live on or in the ground so it makes sense.

My photo captures a battle between two mother insects, one which has the potential to generate a social colony of 9000 worker ants, another which lives a solitary life snatching prey out of the air.

References:

Akre, R. D., L. D. Hansen, and E. A. Myhre. 1994. Colony size and polygyny in carpenter ants (Hymenoptera: Formicidae) J. Kans. Entomol. Soc. 67: 1-9, cited in: Hansen, Laurel and Klotz, John. 2005. Carpenter Ants of the United States and Canada. Cornell University Press.

Ellison, Aaron, Gotell, Nicholas, Farnsworth, Elizabeth, and Alpert, Gary. A Field Guide to the Ants of New England. 2012. Yale University Press.

Hansen, Laurel and Klotz, John. 2005. Carpenter Ants of the United States and Canada. Cornell University Press.

Holldobler, Bert and Wilson, E. O. 1990. The Ants. Harvard University Press.

Marshall, Stephen. 2012. Flies: the Natural History and Diversity of Diptera. Firefly Books.

Peeters, Christian, and Molet, Mathieu. 2010. “Colonial Reproduction and Life Histories” in: Lach, Lori, Parr, Catherine L., and Abbott, Kirsti L.(eds.) 2010. Ant Ecology. Oxford University Press.

I hope you enjoyed my foray into the lives of these fascinating insects. My next post in the ongoing series of My Top Nature Photos is going to be about a sneaky little amphibian.

For Previous posts in this series, see:

1. The Pale-Painted Sand Wasp (Bembix pallidipicta)
2. Moose (Alces alces) Family
3. Canada Jay (Perisoreus canadensis)
4. Common Five-Lined Skink (Plestiodon fasciatus)