Nervous Control of Male Sexual Drive in The Hermaphroditic Snail Lymnaea Stagnalis

Abstract

We studied the role of the prostate gland in determining the level of male sexual drive in the hermaphroditic pond snail Lymnaea stagnalis. Male sexual drive is high after a period of social isolation and decreases after copulation as a male. A positive correlation exists between the level of male sexual drive and the volume of the prostate gland. Like male sexual drive, the volume of the prostate gland increases during a period of social isolation and decreases after copulation as a male. Behavioural experiments demonstrated that animals with a lesion of the nerve that innervates the prostate gland (NP1) have a lower level of male sexual drive after social isolation than control animals. However, lesion of NP1 did not affect the increase in the volume of the prostate gland caused by social isolation. Extracellular recordings from NP1 in a semi-intact preparation show a change in firing pattern during an experimentally induced increase in prostate gland volume. The results indicate that NP1 serves as a nervous pathway for the male sexual drive. We propose a simple motivational model for male sexual behaviour in L. stagnalis in which the volume of the prostate gland sets the level of male sexual drive.

Sublethal heat reduces overall reproductive investment and male allocation in a simultaneously hermaphroditic snail species

“…Previous work has shown that one week of isolation suffices to fully replenish the components of ejaculate in this species, increasing their male mating motivation (Van Duivenboden and Ter Maat 1985;De Boer et al 1997). Thus, we are confident that snails in 28 °C treatment did not fully replenish their sperm reserves.…”

“…We designed the experiment with the aim to measure the consequence of heat on spermatogenesis, even though this species continuously produces sperm after maturation. sPrevious work has shown that one week of isolation suffices to fully replenish the components of ejaculate in this species, increasing their male mating motivation (Van Duivenboden and Ter Maat 1985; De Boer et al 1997). Thus, we are confident that snails in 28 °C treatment did not fully replenish their sperm reserves.…”

“…For identification purposes, we put a small amount of nail polish on the shell of partners. Since the focal snails were isolated for eight days, they were fully motivated to copulate as male (Van Duivenboden and Ter Maat 1985; De Boer et al 1997), and more so than their four-day isolated partners.…”

Effects of the anxiolytic benzodiazepine oxazepam on freshwater gastropod reproduction: a prospective study

“…According to the study of De Boer et al (1996), we hypothesized that only the fourth category, 'long interactions', reflected copulation behavior, but the eversion of the preputium and intromission were very difficult to see due to the small size of R. balthica. Moreover, it has been shown that isolation may facilitate the monitoring of social interactions (more copulations and a shorter total copulation sequence) (Van Duivenboden and Ter Maat, 1985) but it may also disturb other parameters such as the willingness of snails to mate as a male role (Boer et al, 1997) and the quantity of sperm transferred by the sperm donor (Loose and Koene, 2008). To optimize the monitoring of copulation behavior, it would be relevant to use optimal conditions that have already been determined for the observation of the reproduction of small gastropod species, such as Physa acuta and Radix auricularia (Facon et al, 2006;Swart et al, 2020).…”

Dynamics of seminal fluid production after mating

“…To do so, we let the snails copulate, then measured SFP gene expression at 3, 24, 48, and 192 h after mating using reverse-transcription quantitative PCR (qPCR). Monitoring for 1 week after mating is considered reasonable since these snails become highly motivation to copulate as male after 8 days of social isolation (Van Duivenboden & Maat, 1985), and the fullness of the prostate gland is the main driver of this motivational state (De Boer et al, 1997). Moreover, it has been shown that this species increases the production of one of the known SFPs, LyAcp10, 1 day after mating (Swart et al, 2019).…”