Archive | August 17, 2012

Galapagos: The lovely orthopterans

Cookson’s katydid (Nesoecia cooksoni) from Santa Cruz [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII,  image stacked from 6 consecutive shots]

Considering the fact that the archipelago is situated right on the equator, the insect fauna of the Galapagos is shockingly small, with only about 1,500 recorded species. Of these a large proportion is endemic, and additional 400+ introduced species were also recorded at least once. Although I went to the Galapagos mainly to see marine iguanas and Sally Lightfoot crabs, what I was really hoping for was an endemic animal that few visitors to the islands ever get a chance  to meet.
The Cookson’s katydid (Nesoecia cooksoni), named after Commander William Cookson, who visited the Galapagos 40 years after Darwin and collected many marine and land specimens, is one of only two endemic species of katydids in the Galapagos. Knowing the restrictions imposed on every visitor to the islands, I quickly lost any hope of being able to see one of these elusive, nocturnal animals. And so you can imagine my excitement when on the last day of the visit, when our group was spending a night on land (the rest of the time we lived on a boat), one of my co-travelers came to me with a plastic bag holding a beautiful specimen of the Cookson’s katydid that she had found inside her cabin! I quickly set up a small studio in my room (I always travel with a Meet-Your-Neigbours-style setup), and photographed the hell out of it.

Cookson’s katydid (Nesoecia cooksoni) from Santa Cruz; the wings of this species are greatly reduced and used only for sound production [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]

Almost nothing is known about this species’ biology, but these insects are probably omnivorous like their close relatives found in the Yucatan and other parts of Mexico. Just before leaving I visited the entomological collection at the Charles Darwin Research Center, and there I saw a number of specimens from several islands, which differed quite markedly in their appearance. Since this species is flightless, I would not be surprised if these local forms turned out to be genetically distinct species; alas, nobody is currently working on katydids in the Galapagos.

Painted locust (Schistocerca melanocera), found on our boat but probably originating from Fernandina [Canon 7D, Canon 100mm macro, Canon MT-24EX twin light + Canon 580EXII]

Another orthopteran endemic, which is quite common on most islands, is the Painted locust (Schistocerca melanocera), a beautiful insect, often seen sitting on volcanic rocks. These grasshoppers are very good fliers, albeit, like most animal life on the islands, quite approachable and definitely less skittish than any other member of the genus Schistocerca that I have ever seen. On two occasions I found them as stowaways on our boat, and of course took the opportunity to shoot them (using the forbidden flash, ha!)

Of the 38 species of the order Orthoptera (crickets, grasshoppers, and katydids), at least 29 are endemic to the archipelago. The remainder are mostly widely distributed Neotropical species, which arrived to the Galapagos by natural means. Four species, however, are recent arrivals, which got there with people, most likely with timber and other plant products shipped from mainland Ecuador. Among them is a gorgeous conehead katydid, Copiphora brevicauda. It is a predaceous species, which probably, and unfortunately, feeds on the slower and defenseless native species; I saw a couple of individuals at the same spot where the Cookson’s katydid was found.

I am kicking myself for not having brought with me my sound recording equipment, but I never really expected that I would see any of my favorite insects in the Galapagos. But at least I was able to take a few illicit photos.

Conehead (Copiphora brevicauda), an introduced species that probably arrived to the Galapagos in the 1980’s [Canon 7D, Canon 100mm macro, 3 speedlights Canon 580EXII]