PATTERNS OF FLUCTUATING ASYMMETRY IN EARWIG FORCEPS - NO EVIDENCE FORRELIABLE SIGNALING

Fluctuating asymmetry theory can be useful in predicting the mode of s election acting on morphological traits, in particular the patterns th at emerge when fluctuating asymmetry is regressed against trait length . Flat, U-shaped and positive slopes that are associated with high lev els of fluctuating asymmetry are thought to be indicative of traits un der sexual selection as arbitrary traits, whereas negative slopes, aga in with high fluctuating asymmetries, are thought to arise in traits w hose expression is dependent on condition. By measuring asymmetries in the forceps and elytra of 30 earwig (Dermaptera, Forficulina) genera, we find that, although fluctuating asymmetry values are not greater i n the forceps than the elytra as predicted, across species fluctuating asymmetry does increase with increasing forceps exaggeration as expec ted for sexually selected traits. The overall relation between forceps length and fluctuating asymmetry is flat, suggesting that in general forceps are not condition-dependent traits.