Female copulatory status and male mate choice in Neptunea arthritica (Gastropoda: Buccinidae)

The causal relationship between sexual selection and sexual size dimorphism in marine gastropods

“…Most marine gastropods are gonochoric and the majority of sexual selection studies have been carried out on species in the family Littorinidae (Erlandsson & Johannesson, 1994;Erlandsson & Rolán-Alvarez, 1998;Johannesson et al, 2016;Ng & Williams, 2014;Rolán-Alvarez & Ekendahl, 1996;Saur, 1990;Zahradnik, Lemay, & Boulding, 2008); probably as a result of their wide distribution, high abundance (Reid, 1989;Rolán-Alvarez, Austin, & Boulding, 2015) and the fact that sexes can be readily identified (Reid, 1986(Reid, , 1989. There have, however, also been studies on Neptunea arthritica (Lombardo & Goshima, 2010, 2011Lombardo, Takeshita, Abe, & Goshima, 2012) and Rapana venosa (Xue, Zhang, & Liu, 2016) as well as studies on sexual selection on size in several other species (Table 1).…”

Influences of population density on polyandry and patterns of sperm usage in the marine gastropod Rapana venosa

“…Assuming that cost of sperm production and male energy expenditure during copulation are nontrivial, it would be expected for males to adjust their preference towards females after the assessment of female quality (such as body size, mating history, parasitic infection) 34 45 46 . Behavioral observation showed that male R. venosa preferred mating with females that just finished egg-laying, indicating that males might evaluate whether the females had recently mated with other partners and allocate their resources depending on the presence of rival sperm.…”

“…It has previously been shown that males of the marine gastropod Neptunea arthritica can detect sex and maturity of potential mates by chemical cues (e.g. impregnated mucus from other males, sperm or seminal fluid residues, female fluids from the bursa copulatrix or changes in hormone profiles) 46 . A male’s ability to recognize whether a female has already been fertilized may be considered highly adaptive, allowing males to balance the costs and benefits of copulation 40 .…”

“…In most neogastropods, sperm is first received in the copulatory bursa and then transferred over 3 days period to the seminal receptacle where storage and fertilization are thought to occur 46 47 . It is unknown how long ejaculates take to reach the seminal receptacle in R. venosa .…”

“… 25 found that male N. arthritica can achieve considerable reproductive success with a mated female through sperm removal, and paternity distribution was also correlated with female intermating intervals. Additionally, males of R. venosa showed post copulatory guarding behavior to defend their ejaculates, which might considerably increase possibility of the sperm to be transported to seminal receptacle 21 25 46 . Further studies on sperm removal mechanism, morphological traits of males’ genitalia, and ultrastructure of female reproductive tract could improve our understanding of the dynamics of sperm competition in R. venosa.…”