Elegant Canopy Beetles
including one with an "agravating" name
Agra grace Erwin. Source: Erwin (2010), ZooKeys 66: 1-28. CC BY 4.0.
If you have never used the words beetle and elegant in the same sentence, perhaps it is because you have not yet had the pleasure of encountering a species of the genus Agra in the Neotropics. These beetles have been referred to as the Elegant Canopy Beetles, and indeed they are. Their head and, even more so, the pronotum that follows are elongated and much narrower than the elytra, or hardened forewings, that cover the posterior portions of the thorax and abdomen. Agra are noteworthy for their beauty (okay, in an insect kind of way), brilliant metallic colors and diverse surface sculpturing.
The late Dr. Terry L. Erwin of the Smithsonian Institution published many papers on Agra. If you know the 1990 film Arachnophobia, you may recall the opening scene when a canister of pesticide is shot high into a tropical rainforest canopy followed by thousands of insects (and spiders) raining down on outstretched collecting sheets near the ground. That method of accessing the previously unexplored insect fauna of tropical forest canopies was perfected by Erwin, whose early work on the canopy fauna forever changed our perception of insect diversity. It was Erwin who staggered the entomology world with evidence that the number of insect species was multiples of the two million or so species that had long been assumed. Among the six-legged treasures he recovered from his collecting trips were many examples of the genus Agra.
I have always had enormous admiration for Terry. His PhD thesis on bombardier beetles was pioneering and superb. Published in 1970, it was among the first studies in North America to analyze phylogenetic relationships with the then radically new ideas of the German entomologist Willi Hennig. And Terry was a natural showman. He intuitively knew how to elevate a discovery or set of facts in a way that captured people’s imaginations.
I owe a great personal debt to Terry for influencing the course of my career, beyond his publications that I studied carefully. When I was a graduate student at Ohio State, I received a phone call out of the blue from Dr. Erwin. He asked if I would like to go to Panama. It took a full nanosecond to respond, and soon I was on my first trip to the Neotropics. I ran a line of pitfall traps for Terry’s study of beetles associated with fig falls, then had the balance of the day to collect for myself. It was a life-changing experience and one of countless examples of his generous spirit.
At that point, I had never met or even seen Dr. Erwin. Before traveling to the Smithsonian to be trained by Terry and put on a flight to Panama City, I had an unexpected surprise. Watching an episode of What’s My Line, I sat up straight when the contestants introduced themselves, saying “My name is Terry Erwin.” The process of elimination was an easy one for me. One was a woman, and I knew Terry was not. And a second gave a ridiculously low number when asked how many kinds of beetles there are.
It is probable that Agra are predominantly predators on other arthropods. Adults have been seen consuming exudates from shoots and leaves, and feeding on pollen. And when I was in Panama, I offered an Agra a tree snail which it appeared to feed upon for a period of time, sticking its head deep into the shell. There are some species found on grasses in savannahs, but most are associated with high canopies. They are nocturnal and are attracted to lights. They secrete defensive chemicals that deter predators, and have been shown to ward off bats. Ventral patches of setae on males suggest that they use pheromones to attract females.
Paradoxically, these canopy beetles belong to the family Carabidae, with the common name ground beetles. Since Fabricius named the first species of Agra in 1801, about 600 additional species have been described. But this is only a good start. As many as 2000 species are estimated to have already been collected and deposited in museum collections, waiting to be named.
Among the many species of Agra described by Erwin are some with especially interesting names. There are quite a few patronyms, mostly named in honor of science colleagues, such as Agra eowilsoni for the late E. O. Wilson. But Hollywood received its due as well, with Agra katewinsletae and Agra schwarzeneggeri. And there is even a nod to the Bard, with Agra othello. There are many species named for an unusual bit of morphology or the geographic location where they were discovered. Erwin even had fun with place names. There is Agra bci that, to any biologist, is recognizable as the Smithsonian’s field station in Panama on Barro Colorado Island. But my favorites are the humorous ones, including:
Agra smurf; Agra yeti and Agra sasquatch (in case you’re wondering, yes, they have unusually big feet); Agra yoda; Agra vate; Agra vation; and, wait for it, Agra cadabra.
Some traditionalists have taken a dim view of such playful names, but I strongly disagree. Species with funny names, and those named in honor of celebrities, are both memorable and capture the attention of the public. How many of the 20,000 or so species named last year did you hear about? I thought as much. But humorous names and those making reference to pop culture icons frequently find their way into mass media, bringing much needed attention to species exploration, taxonomy and biodiversity.
Further Reading
Erwin, T. L. (1970) A reclassification of bombardier beetles and a taxonomic revision of the North and Middle American species (Carabidae: Brachinida). Quaestiones entomologicae 6: 4-215.
Erwin, T. L. (2010) Agra, arboreal beetles of Neotropical forests: pusilla group and piranha group systematics and notes on their ways of life (Coleoptera, Carabidae, Lebiini, Agrina). ZooKeys 66: 1-28.