Halobates sp. (Hemiptera: Gerridae) at Castle Beach, Kailua, Hawaii
The tradewinds have been fairly strong lately, so this past Saturday I went for an early morning stroll along a beach a few minutes from where we live to see if I could find some Halobates. The genus Halobates consists of water striders (Gerridae) that live almost entirely in marine habitats and contains the only insect species living in the open ocean (The Marine Insect Halobates (Heteroptera: Gerridae): Biology, Adaptations, Distribution, and Phylogeney, Oceanography and Marine Biology: An Annual Review 2004, Nils Moller Andersen and Lanna Cheng 42:119–180).
Usually when the winds are strong you find these little guys on the windward side of Oahu hopping around in the sand, and I’ve always wanted to get some images of them, so I thought I would give it it a try. I also wanted to test out the macro abilities of my new camera. I recently bought a Canon Powershot SX30 IS – it wasn’t my first choice, but I couldn’t really justify getting a decent SLR and macro lens worth more than our minivan, so I had to make some compromises. I think it will work out OK for my purposes, and with a few accessories I should be able to get some decent insect macro shots. Having said that, it is still painfully obvious that the Canon 30D and 100 mm macro lens that I had access to at work were much better.
I did manage to find a few stranded striders hiding out in depressions in the sand. I’m not sure if these are H. hawaiiensis or H. sericeus. From what I’ve read, H. hawaiiensis is a near shore/coastal species and H. sericeus is an open ocean species, so I’m guessing that maybe these are H. sericeus that have been blown in with the trades, but that is only a guess (Biological Notes on the Pelagic Water Striders (Halobates) of the Hawaiian Islands, with Description of a New Species from Waikiki (Gerridae, Hemiptera), Proceedings of the Hawaiian Entomolgoical Society, 1938, Robert L. Usinger, 10:77-88).