Duration of pairing and use of allosperm in Biomphalaria glabrata (Gastropoda: Planorbidae)

Abstract

Virgin homozygous black pigmented and albino Biomphalaria glabrata are paired during a period varying from 1 to 20 days. The rate of cross-fertilized parents is statistically similar for the various lengths of pairing. As a whole, nearly 80% of the albino snails produce a pigmented progeny. This production begins as soon as the snails are mated and continues after their separation. To measure the actual use of the allosperm, its use during the postmating period must be added to the length of mating. So, it appears that the real use of the allosperm is statistically constant (mean slightly inferior to 8 weeks) and not related to the length of the previous pairing.

No effect of mate novelty on sexual motivation in the freshwater snail Biomphalaria glabrata

“…However, even if these cues were informative for individual discrimination, the causative mucus components decay within 10 to 30 min [ 54 , 55 ] and would thus only work as a short term self-referent cue. Given a delay between copulations of 1 h and more and the long time over which received allosperm can be stored to produce fully fertile egg masses (3 weeks at least, [ 52 , 56 ]), this mechanism appears insufficient to allow partner discrimination in B. glabrata . Second, snails may individually recognise previous partners as recently shown for a burying beetle [ 26 ].…”

Bateman Gradients in Hermaphrodites: An Extended Approach to Quantify Sexual Selection

“…Snails lay multiple transparent egg masses per week, each containing ∼15-30 eggs (Pimentel 1957;). Because of inbreeding depression, offspring are typically outcrossed when allosperm are available, but snails readily self-fertilize when sexually isolated (Vianey-Liaud 1976;Vianey-Liaud et al 1989).…”

Increase in multiple paternity across the reproductive lifespan in a sperm‐storing, hermaphroditic freshwater snail

“…The most likely explanation is an increase in the number of mating partners contributing sperm to a snail's allosperm reservoir. Although not yet shown for R. balthica , sperm storage and its utilization later in time have been documented in several species of Basommatophoran freshwater snails (Cain, ; Madsen et al., ; Nakadera et al., ; Vianey‐Liaud et al., ). We thus hypothesize that the number of fathers per clutch increases because snails habitually store and mix received sperm and only use it little by little.…”

“…In addition, the frequency and extent of multiple paternity in a population may change during an individual's lifetime, something that has never been studied in a free‐living hermaphrodite (but see Angeloni et al., ; Kupfernagel & Baur, ; Janssen & Baur, for studies using laboratory‐produced progenies of field‐collected adults). The occurrence of temporal changes in multiple paternity is likely because many hermaphroditic species have, just like numerous gonochorists, the ability to store, mix and potentially choose between received sperm from earlier matings (e.g., Cain, ; Madsen, Waithaka Thiongo, & Ouma, ; Nakadera, Blom, & Koene, ; Vianey‐Liaud, Nassi, Lancastre, & Dupouy, ).…”

“…Even though this species is self‐compatible (Haun, Salinger, Pachzelt, & Pfenninger, ; Pfenninger, Salinger, Haun, & Feldmeyer, ), selfing is very rare in the study population (Bürkli, Sieber, Seppälä, & Jokela, ). Copulation is unilateral, and both sperm digestion (shown in Lymnaea stagnalis : Koene et al., ) and sperm storage (shown in Biomphalaria glabrata , Helisoma duryi and Lymnaea stagnalis : Cain, ; Madsen et al., ; Vianey‐Liaud et al., ; Nakadera et al., ) are probably common, allowing for alternative individual‐level sex‐role decisions and patterns of fertilization. In the study population, snails have a single reproductive season of roughly three months, throughout which we collected clutches in which we estimated multiple paternity.…”