Do asymmetric sexual interactions affect copulation in the saw-toothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae)?

Abstract

Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) is a widely distributed key stored-product insect pest. Recent research efforts have been conducted on the laterality (i.e., left-right asymmetries in brain and behavior) during courtship and mating of coleopteran species that are related to stored products. However, our knowledge on the potential impact of repeated sexual interactions on insect mating laterality is limited. In this frame, we investigated the mating and laterality behavior of O. surinamensis. Males showed right-biased (47.6%) population-level mounting towards females, with 35.7% copulation success, followed by left-biased males (32.9%) and backside males (19.5%), with 26.6% and 7.7% successful copulations, respectively. Males preferring the right or the left side of female's body achieved higher copulation success if compared to backside-approaching males. Mate recognition duration in right-biased males (436.9 s) was significantly lower over left-biased ones (678.5 s). Significant differences in precopulation duration were noted among left- (181.4 s) and right-biased males (261.3 s), while copulation duration did not differ between males approaching from different sides. Besides male laterality, tapping behavior duration increased with the increase of the number of copulations, while the duration of each repeated copulation decreased with the increase of the copulation number. Overall, our study adds useful knowledge on mating behavior of O. surinamensis, highlighting how lateralized behavioral traits impact male copulation success over repeated sexual interactions.