The odor of origin: kinship and geographical distance are reflected in the marking pheromone of male beewolves (Philanthus triangulum F., Hymenoptera, Crabronidae).
BACKGROUND
Pheromones play an important role for mate finding and courtship in many insects. In species where males are the signaling sex, females are expected to choose among potential mates with regard to the emitter's quality and/or genetic compatibility. One important aspect is the balance between negative and positive effects of in- vs. outbreeding. In the present study, we aimed to assess the potential of the territory marking pheromone of European beewolves as an indicator for genetic compatibility in the context of female choice.


RESULTS
We analyzed the sex pheromone composition of male European beewolves (Philanthus triangulum F., Hymenoptera, Crabronidae) from eight different locations across Central Europe (six in Germany, one in England, and one in Italy). The pheromone constitutes a complex blend of various long-chain hydrocarbons (alkanes, alkenes, alcohols, ketones, and a carbon acid). We demonstrate that pheromone composition differs significantly among distant populations (regional scale), among subpopulations (local scale) and between families within subpopulations. The differences in the pheromone blend are positively correlated with geographical distances as might be expected according to an isolation-by-distance model. On a local scale, family membership has a larger effect on pheromone composition than subpopulation affiliation, while the reverse is true for the regional scale.


CONCLUSIONS
Our results show that male pheromones can contain information on both kinship and geographical origin that may be used by females to choose adaptively among potential mates on the basis of their genetic distance.
Kaltenpoth
Martin
M
University of Würzburg, Department for Animal Ecology and Tropical Biology, Am Hubland, 97074 Würzburg, Germany. martin.kaltenpoth@biologie.uni-regensburg.de
Kroiss
Johannes
J
Strohm
Erhard
E
D000818:Animals; D016010:Binomial Distribution; D016002:Discriminant Analysis; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D009812:Odorants / Q000032:analysis; D025341:Principal Component Analysis; D012724:Sex Attractants / Q000737:chemistry*; D014863:Wasps / Q000737:chemistry* / Q000145:classification
D012724:Sex Attractants