Preliminary assessment of mating duration and prolonged post-copulatory associations in Arrenurus water mites (Actinotrichida: Parasitengonina: Hydrachnidiae)

Mariusz Więcek,Heather C Proctor,Jacek Dabert,Karen Wilkinson

doi:10.24349/qrp6-e0na

Mariusz Więcek, Heather C Proctor + Show 2 more

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https://doi.org/10.24349/qrp6-e0na

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Abstract

Conflicts of interest between the sexes over control of mating can be reflected in various aspects of morphology and behaviour, including structure of genitalia and copulation duration. In Arrenurus water mites (Hydrachnidia: Arrenuridae) there are two main patterns of sperm transfer that differ in degree of potential male control of sperm uptake by females. In some species, males are equipped with an intromittent organ (the ‘petiole’) that is used to forcefully insert sperm into the female reproductive tract. In others, males lack an intromittent organ and females appear to push sperm into their reproductive opening themselves. Theory suggests that the amount of time spent in courtship after sperm transfer should differ between males with and without an intromittent structure. We predicted that male Arrenurus able to push sperm into the female’s reproductive tract (petiolate males) should spend less time courting females after transferring sperm than apetiolate males, which may have to ‘convince’ females to take up their sperm. Here, we examined durations of mating for 11 species of Arrenurus with males that differ in genital morphology: seven species with males equipped with a well-developed petiole (= ‘petiolate’ species) and four species with males that either completely lack a petiole or have a minute peg-like petiole that does not appear to function as an intromittent organ (= ‘apetiolate’ species). We tested whether males of petiolate species spend less time in the stage of courtship that takes place after sperm transfer (= ‘post-transfer courtship’) than apetiolate males. In contrast to our prediction, we found that species with well developed petioles spent significantly more time in post-transfer behaviours than species lacking petioles. The possible function of protracted post-transfer courtship in the genus Arrenurus is discussed.

Highlights

Sexual selection theory was initially proposed to explain the existence of sexual dimorphism in species in which there is little ecological differentiation between the sexes (Darwin 1859).How to cite this article Więcek M. et al (2022), Preliminary assessment of mating duration and prolonged postcopulatory associations in Arrenurus water mites (Actinotrichida: Parasitengonina: Hydrachnidiae)
Total mating duration ranged from 29.00 ± 5.00 minutes in apetiolate A. stecki to 630.00 ± 79.00 minutes in petiolate A. bicuspidator (Table 1)
We had expected that Arrenurus males with a well-developed intromittent structure would spend less time in courtship behaviours after sperm transfer than apetiolate males, which appear to have less coercive control over whether sperm moves into the female’s reproductive tract

Summary

Introduction

Sexual selection theory was initially proposed to explain the existence of sexual dimorphism in species in which there is little ecological differentiation between the sexes (Darwin 1859).How to cite this article Więcek M. et al (2022), Preliminary assessment of mating duration and prolonged postcopulatory associations in Arrenurus water mites (Actinotrichida: Parasitengonina: Hydrachnidiae). Sexual selection theory was initially proposed to explain the existence of sexual dimorphism in species in which there is little ecological differentiation between the sexes (Darwin 1859). There are situations where males show morphological, physiological and behavioural adaptations that appear to bypass female choice. Sexual conflict theory argues that in some species, male genitalia and behaviour evolved to force females to mate (= coercion). If this reduces female fitness, this should select for female resistance to male coercive morphology and behaviour (Arnqvist and Rowe 2005). Evolutionary conflicts of interest can apply to which sex controls mating rate, copulation duration, female remating propensity and fertilization of eggs (Edvardsson and Canal 2006; Tong et al 2021)

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