I found a big rove beetle in my yard today, and I decided to take some photos of its giant mandibles. It was behaving oddly – maybe just because it didn’t like my attentions, or maybe because it was parasitized. I decided to do some research into rove beetle parasites, and I discovered something tangential that blew my mind: rove beetles eat parasites!!
As I might have mentioned before, I’m really interested in predation on parasites, and I have a special soft spot for mutualistic organisms that eat parasites. It turns out that there is a whole group of rove beetles (Amblyopinus) that live on rodents and in their nests. These beetles were originally classified as parasites of rodents, but Ashe and Timm (1987) argued that they didn’t appear to be parasitic; rodents did not try to groom off their rove beetles, and beetles were never seen damaging host tissues. Instead, Ashe and Timm (1987) found that the rove beetles hang out in the rodents’ nests during the day, eating ectoparasites, and hang out on the rodents at night so that they get free transportation among nests. AWESOME!
I think that this is the first time I’ve heard of multicellular symbionts of mammals that eat parasites. Can you think of any others? Remoras on cetaceans?
Ashe, J.S., and R.M. Timm. 1987. Probable mutualistic association between staphylinid beetles (Amblyopinus) and their rodent hosts. Journal of Tropical Ecology, 3(2): 177-181.