The freshwater snail ., 2008) from seven localities in the Netherlands in 20 (Fig.1; Table 1): Alkmaar Noord (AN), Amstelveen (AV), Eemnes (E), Hollandsche Rading (HR), Jaagpad in Amsterdam (J), Oterleek (OT) and Purmerend (PU).Your access to the NCBI website at gov has been temporarily blocked due to a possible misuse/abuse situation involving your site.This is not an indication of a security issue such as a virus or attack.It could be something as simple as a run away script or learning how to better use E-utilities, for more efficient work such that your work does not impact the ability of other researchers to also use our site.
The habitat type of AN is a deep and stagnant ditch, and two persons spent 90 min searching the whole area, due to the extremely low density.
As a consequence, when females mate with multiple partners, they can store sperm from several partners in their reproductive tracts, providing the opportunity for sperm competition, cryptic female choice and thus postcopulatory sexual selection (e.g. Hence, the number of mates is an important determinant for the potential for postcopulatory sexual selection, as supported by theoretical predictions (e.g. Furthermore, the number of mates is especially fascinating to examine in simultaneous hermaphrodites (which are male and female at the same time, hereafter called hermaphrodites).
On the one hand, it has been predicted that hermaphrodites have a limited number of mates in the wild, based on their low chance to find a mate and/or low mobility (Charnov, Maynard Smith & Bull, 1976; Charnov, 1982).
Although our survey only provides an initial insight into the situation in the field, the results do highlight the potential for postcopulatory sexual selection in natural populations of this simultaneous hermaphrodite.
There are very few species that are strictly monogamous.