Are solifugids really predators of bed bugs?
Last week I gave a skeptical tweet regarding a segment of “Ask the Bugman” in the San Francisco Chronicle in which somone wrote in inquiring about natural enemies of bed bugs and Bugman included solpugids in his answer. Camelspiders? Sunspiders? Windscorpions? Really? These nasty looking arachnids have been the subject of so much misinformation and bogus claims that I thought for sure this was another perpetuated myth.
Soon, however, I began to feel some apprehension over the possibility that I was too quick to dismiss this, so I wasted yet more of my life on the internet and turned to Google for enlightenment. I quickly noticed that this little sun spider factoid was repeated in many places:
1) Earthlife.net – “…some species are more specialised, Solpuga sericea and Solpuga lineata burrow into the soil in order to feed on termites while a Californian species of the genera Eremobates enters bees hives and feeds on the bees and Eremobates pallipes from Colarado is suspected of hunting ‘bedbugs’.”
2) Handbook of Urban Insects and Arachnids, by William H. Robinson – “A California species of Eremobates kills bees, and a small nocturnal species, E. pallipes, is known to prey on bed bugs.”
3) Spiders, scorpions, centipedes, and mites; the ecology and natural history of woodlice, myriapods, and arachnids, by J. L. Cloudsley-Thompson – “The small nocturnal species E. pallipes from Colorado is said to hunt bed-bugs.”
4) And finally, in The Biology of Camel Spiders (Arachnida, Solifugae), by Fred Punzo, I found a reference – “One eremobatid solifuge from Colorado, Eremobates pallipes, has been reported to feed extensively on the bed bug, Cimex lectularius (Muma, 1967).”
I was able to get a PDF of Martin H. Muma’s paper titled, “Basic Behavior of North American Solpugida” contained in pages 115-123 of Vol. 50 No. 2 of the The Florida Entomolgist, and I found what appears to be the source of these claims. From the introduction on page 115:
OK, so maybe this maybe makes a little sense (my apologies to the Bugman). However, if it were me, I probably would not include windscorpions in a list of common bed bug predators. If you’re going to include solifugids, then you should include every other nocturnal, generalist predator of insects. In no way am I an expert on the Solifugae, but, from this Florida Entomologist reference alone, I wouldn’t term this species a specialist on bed bugs. I think the behavior reported in the paper would be more a result of the fact that, in the year 1871, bed bugs were much more common than they are today (even with the recent resurgence of bed bugs in the US), and human dwellings were probably much more accessible to wind scorpions. Hence, back in the day, Eremobates pallipes and Cimex lectularius shared the same space. These days, I doubt the worlds of bed bugs and windscorpions collide very often, except maybe in extreme circumstances. I’ve never really lived out West in an area where solifugids are common, so I can’t speak from experience, but I have a hard time believing in 2011 they are commonly found in bedrooms. And the fact that in captivity they showed a preference for bed bugs as food doesn’t surprise me. If I were a predatory arthropod, I would also probably show preference for a bed bug over something like a roach as a late night snack – that would be like having the choice between a juice filled gummy bear or a crust of bread.
Perhaps more telling is the omission of this reference in other descriptions of Eremobates pallipes from other respected sources, such as the University of California IPM Online site, where on the wind scorpion page, there is no mention of bed bugs as prey. With regard to prey, all that is state is that “wind scorpions feed primarily on living insects, spiders, and other small creatures such as lizards that they catch.” The same is true for a Texas A&M site on wind scorpions – no mention of bed bugs.
So, yes, windscorpions are predators of bed bugs, but I was only able to find a reference supporting this for one species, Eremobates pallipes, and these days I doubt this interaction occurs with great regularity in the United States. Nevertheless, I can’t fault the Bugman for his answer. His response about the pyrethroid insecticide Suspend is another story though…restricted use? Really?