15 June 2009

Evolution 2009: Day two

Evolution 2009
ResearchBlogging.org
After a late (early) night yesterday, I started my day at the R.A. Fisher Award talk, a presentation of results from "an outstanding Ph.D. dissertation paper published in the journal Evolution." This year's winner turned out to be a paper I remember reading when it was first published, in which Megan Higgie and Mark Blows showed that sexual selection for mate-signaling hydrocarbons in Drosophila serrata is opposed by selection to avoid mating with the closely related D. birchii. Populations of D. serrata that occur with D. birchii have been selected for different hydrocarbon profiles [$-a] than populations that don't occur with D. birchii -- so that adaptive speciation could result from the opposing selective regimes.


Photo by Jo Mur.
On a more natural history-oriented note, today I learned that honeyguides, the African birds known for their habit of guiding badgers (or humans) to bees' nests, are also particularly vicious brood parasites. Like cuckoos and cowbirds, honeyguides lay their eggs in the nests of other bird species, and let the parasitized parents raise 'em. Apparently the Greater Honeyguide (the chick in the figure provided) has had its eggs selected to more closely match a variety of host species.

Other highlights:
  • Flowers of the genus Pedicularis are more different in co-occuring species than would be expected by chance, possibly to minimize the chance that their shared pollinators, bumblebees, transfer pollen between different species.
  • When female Hadena bircuris moths pollinate their host plant Silene latifolia, they lay eggs on the flower so that their larvae can eat some of the seeds produced -- much like yucca moths -- but male moths of the same species also pollinate, and this may help offset the cost of female pollination.
  • Host-parasite coevolution may actually drive the evolution of mutation rates in the host and the parasite, much like yesterday's demonstration that coevolution can alter migration rates.
Finished the day much more quietly than yesterday, with a handful of folks at my place for burgers and beer. And, hey, I'm getting to bed before 4 a.m.!

References

Higgie, M., & Blows, M. (2008). The evolution of reproductive character displacement conflicts with how sexual selection operates within a species. Evolution, 62 (5), 1192-203 DOI: 10.1111/j.1558-5646.2008.00357.x

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