Mating behaviour of the large-head resin bee Heriades truncorum (Megachilidae: Osminii) suggests female plastic strategy in selection of a mating partner and male quality assessment

Samuel Boff

doi:10.1007/s13592-022-00916-7

Abstract

Behavioural courtship display and size of males are two attributes often used by females to select a mating partner. According to sexual selection, such traits are of importance, because a bigger size male or males displaying a better courtship could enhance the possibility of females to transmit her genes to the following generations via her offspring. In Hymenoptera such as in solitary bees, it is known that females can assess male quality and add this information in the process of mating choice. In the current study, I describe aspects of pre-copulatory mating behaviour of males, male quality assessment and female choice in the large-headed resin bee Heriades truncorum (Hymenoptera: Megachilidae: Osminii). Males of Heriades truncorum perform thoracic vibration, fan their wings and lift upwards female’s abdomen to copulate. Couples engage in sideways rocking motion movement like a dance. Female selection of a partner was also found to be density dependent. In a pair situation (one female for one male), female copulate equally with males of all sizes and male mating effort enhanced the chance of successful copulation. In an environment with mating choices (one female for two males of different sizes), successful copulation was significantly more frequent for bigger size males. Female response to male mounting took place independently of the number of mating partners in the arena and did not impair mating. Additionally, size had no effect on male-male competition. Both results suggest mating success in Heriades truncorum rely on a female choice mechanism.

Highlights

Mating behaviour strategy including male courtship display, as well as the interference of body size in mating, are primary goals to understand evolutionary aspects of mating success and female choice (Alcock 2013)
Male body size has been found to be correlated with male success in solitary bee species performing scramble competition (Ayasse et al 2001; Russell et al 2018) which predicts that a finite resource is accessible to all competitors
I tested if the size of the mating partners influences mating attempts with a generalized liner models (GLMs) and Poisson error structure

Summary

Introduction

Mating behaviour strategy including male courtship display, as well as the interference of body size in mating, are primary goals to understand evolutionary aspects of mating success and female choice (Alcock 2013). Pre-copulatory behaviour is often used by males to attract mating partners. Male fruit flies (Drosophilidae) vibrate the wings in pre-copulatory behaviour producing a song that is used by the female to assess male quality (Hoikkala et al 1999). In Hymenoptera, such as solitary bees, males are known to display sexual signals used by female to assess male quality. Male body size has been found to be correlated with male success in solitary bee species performing scramble competition (Ayasse et al 2001; Russell et al 2018) which predicts that a finite resource (e.g. females) is accessible to all competitors

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