Reproductive investment-snail


The reproductive success of an organism determines the survival probability of a population. Especially female reproductive success is thought to depend on the reserves that an organism has available. But how and why do organisms decide how much they should invest per offspring? In this internship, this can be addressed by focussing on the relationship between mating regime and female reproductive success using the hermaphrodite pond snail Lymnaea stagnalis. The snails can be experimentally exposed to different mating regimes and for each of these, the reproductive output (number and size of eggs) and embryonic development (hatching time and hatchling size) will be observed.

This approach can be extended by investigating whether changes in reproductive output are induced by seminal fluid components that are transferred along with the sperm. Another extension could be to also include male reproductive investment. Ultimately, this is essential for understand how these hermaphrodites allocate their resources over their male and female functions (sex allocation).


– Behavioural observations
– Quantifying reproductive output
– Digital measuring of eggs
– Determining hatching success

Essential reading:

Nakadera, Y., Swart, E.M., Hoffer, J.N.A., Den Boon, O., Ellers, J. & Koene, J.M. 2014. Receipt of seminal fluid proteins causes reduction of male investment in a simultaneous hermaphrodite. Current Biology 24: 1-4

Van Iersel, S., Swart, E.M., Nakadera, Y., Van Straalen, N.M. & Koene, J.M. 2014. Effect of male accessory gland products on egg laying in gastropod molluscs. Journal of Visualized Experiments 88: e51698

Hoffer, J.N.A., Schwegler, D., Ellers, J. & Koene, J.M. (2012). Mating rate influence female reproductive investment in a simultaneous hermaphrodite, Lymnaea stagnalis. Animal Behaviour84: 523-529

Scharer, L. (2009). Tests of sex allocation theory in simultaneously hermaphroditic animals. Evolution63: 1377-1405


Dr. Joris M. Koene
Room: H-147
E-mail: joris.koene@vu.nl
Phone: +31 (0)20 – 59 87095

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