Monday, December 10, 2007 - 8:17 AM

Investigating the role of sexual selection in green lacewing speciation

Suegene Noh,, University of Connecticut, Department of Ecology and Evolutionary Biology, 75 N Eagleville Rd, U-3043, Storrs, CT

Green lacewings in the Chrysoperla carnea species group are morphologically cryptic but clearly distinguishable via substrate-borne vibrational mating signals that both sexes produce. These species-specific mating signals are important in species recognition and thus were previously hypothesized to have contributed to speciation via sexual selection. My objective was to test for sexual selection within the species Chrysoperla lucasina, a widespread member of the carnea group which produces multi-volley signals. Also, C. lucasina is sympatric with four other members of the carnea group across southern Europe. Thus the results of this study have the potential to shed light on the link between sexual selection within a species to species recognition between species. I investigated responsiveness, discrimination, and preference functions for volley period and duration. The following research questions were addressed: (1) Is there individual variation in these variables, and is it repeatable? (2) Is there evidence for sexual selection in males vs. females, and is the selective pressure in the same direction? Individuals were given two series each of synthesized playback signals with varying volley period (1.13 1.83 s) and duration (0.6 - 1.3 s) in random sequence. Individual preference functions were found to be non-repeatable. Males were less responsive but females were more discriminating. Males were more variable in their responses compared to females. Females preferred signals with intermediate periods whereas males preferred signals with shorter periods. Males preferred signals with longer duration while female preference was not significant. In summary, the sexes were significantly different in their preferences.

Species 1: Neuroptera Chrysopidae Chrysoperla lucasina
Species 2: Neuroptera Chrysopidae Chrysoperla carnea