LK Hodgkin, MA Elgar, MRE Symonds (2010) Positive and negative effects of phoretic mite species on the reproductive output of an invasive bark beetle. Australian Journal of Zoology 58 (2010), 198-204
What’s it about?
Ips grandicollis bark beetles are frequently covered (sometimes so heavily you can barely see the beetle) in phoretic mites. (Phoretic means they are carried around by the beetle). What effect does this have on the fitness of the beetle? We found that whilst these beetles have detrimental effects on the number of offspring produced by adult beetles, those offspring tend to be better off as a result of mite presence. The mites appear to have both parasitic and mutualistic properties, depending on life stage of the beetle.
What’s the story behind it?
I had noticed, whilst doing field work on these beetles that they were riddled with mites and wondered what was going on there? Before she became a PhD student, Lisa investigated this question in her honours project. She painstakingly manipulated mite loads on hundreds of beetles to see how this affected reproductive output. I’m pretty sure she has no desire to handle a bark beetle ever again, let alone the mites. To cap it all the statistical analysis was a complete nightmare as well.
We had a really hard time getting this paper published, principally because we didn’t taxonomically identify the mite species involved. This always seemed to me a bit beside the point, and I wondered why reviewers got so hung up on it – after all the effects were still the same, regardless of exact mite identity.