I observed horseflies (Tabaniidae) biting bottlenose dolphins (Tursiops truncatus) in a caribbean mangrove area. I can't find reports on bloodsucking insects predating on completely aquatic mammals (dolphins, whales, manatees). Does anyone have any information/paper about the subject?
My guess is that the dolphins offer an attractive cue: Horseflies are known to be attracted by polarized light from the surfaces of their hosts. They are easily trapped by glossy black surfaces that reflect polarized light. For more information see publications of Gabor Horvath or his book
Polarized Light and Polarization Vision in Animal Sciences
Springer Series in Vision Research, volume 2, 2014, page 649
editor: Gabor Horvath
series editors: Shaun P. Collin, Justin N. Marshall
Springer-Verlag: Heidelberg, Berlin, New York
http://www.springer.com/life+sciences/animal+sciences/book/978-3-642-54717-1
https://arago.elte.hu/sites/default/files/Front-material_Springer-PolBook-2014.pdf
Hi Nataly,
There are reports of manatees being bitten by mosquitos while in captivity in Miami. It is likely that they therefore also may get bitten while surface resting in areas where there are lots of mosquitos in the wild. The horseflies also are attracted to the manatee's dark skin while out of the water during biomedical examination in the wild.
Thanks Bob, I have also seen horseflies bitting Amazonian manatees in captivity, when they are resting at the surface. I wonder if those insects can be vectors of any disease.
Hi Nataly,
I have already watched on TV horseflies biting partially submerged crocodiles. I think it was in one of the David Attenborough's series.
I hope that may help you.
Best regards,
Thibaut
Yes! It has been documented for crocodiles and other reptiles. I actually found a paper: Henriquez et al. 2000. Betrequia ocellata Oldroyd (Diptera, Tabanidae, Rhinomyzini) blood feeding on Caiman crocodilus (Linnaeus)(Crocodylia, Alligatoridae) in Manaus, Brazil
There are tabanids that not only feed on crocodylians, but hold on when the reptile leaps for food or even submerges for short periods. I have observed this in wild estuarine crocodiles, Crocodylus porosus.
Thanks for all your answers, I am coming back with this subject. Anyone interested in putting data together for a review on tabanids feeding on large aquatic vertebrates?
Great idea, Natalie. On the topic of potential disease transmission of biting insects to manatees, check with Dr. Greg Bossart. He was the one reporting the incident with captives in Miami. I'll help with my observations in the field if that is useful.
Hi Nataly,
I don't know publications on diseases transmitted by horseflies for marine mammals, but there are some reports of viral diseases transmitted by mosquitoes to cetaceans (West Nile virus, St. Louis encephalitis virus), causing encephalitis. There is serological evidence of contact of bottlenose dolphins with viruses transmitted by insects (Eastern and Venezuelan encephalitis virus and West Nile virus) on the east coast of the US. Wild manatees in Belize were evaluated for these same virus, but all animals tested were seronegative. Regards! Vitor
ps: sorry for the english : /
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