Sex and conflict in simultaneous hermaphrodites; behaviour, physiology, morphology and evolution

repro 1

Background

In animal species that mate promiscuously, store sperm and fertilise internally, the sperm from two or more donors usually compete for access to eggs. Such sperm competition often leads to sexual conflict, because traits that are advantageous to the sperm donor can be harmful to the recipient. In species with separate sexes, many recent studies have focussed on sperm competition, sexual conflicts and counter-adaptive arms races, and have shown their severe impact on the evolution of mating interactions, genital morphologies, gametes, seminal products and speciation. For simultaneous hermaphrodites, despite substantial theoretical work, it remains unclear how the evolution of many of such processes and characteristics are affected. Moreover, the mechanism underlying sperm competition, sexual conflicts and counter-adaptive arms races remain largely unexplored.
Our aim is to address these proximate and ultimate questions using the freshwater snail Lymnaea stagnalis. Ultimate issues to be tackled are the evolution of reproductive morphology and seminal fluid components (sex peptides/proteins) between species as well as the functional significance of differences in lifetime reproductive success they cause within L. stagnalis. Proximate issues include the development of these differences as well as the mechanism underlying mating decisions and differential sperm allocation. The integrative nature of this research implies the use of a range of techniques (see below). In addition, we aim to compare the findings in our model species (great pond snail L. stagnalis) with those in other species using a comparative approach.

Topics

– Sperm storage in pond snails: where and how long?
– Sex allocation: experimental manipulation of male and female reproduction
– Are pheromones involved in mate choice?
– The influence of seminal fluid substances on sex allocation
– Hormonal and neuronal regulation of reproductive processes and motivation
– The evolution of reproductive morphology and seminal fluid proteins in freshwater snails
– Identification and genetic characterisation of seminal fluid components
– Sperm competition in the field.

Approaches

– Behavioural observations
– Biochemical analyses of sex peptides and (allo)hormones
– Electrophysiology
– Field work
– Identification of sex peptide/allohormone-encoding genes
– Immunohistochemistry
– Micro-surgery techniques
– Molecular phylogeny reconstruction
– Neuroanatomy
– Paternity analysis
– Quantifying behaviour
– Quantifying resource investment
– Sperm counting

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 influences female reproductive investment in a simultaneous hermaphrodite, Lymnaea stagnalis. Animal Behaviour 84: 523-529

Jarne, P., David, P., Pointier, J.-P. & Koene, J.M. 2010. Basommatophoran Gastropods. In The Evolution of primary sexual characters in animals (eds. A. Córdoba-Aguilar & J.L. Leonard), pp. 173-196, Oxford University Press

Koene, J.M. & Ter Maat, A., 2001. “Allohormones”: A class of bioactive substances favoured by sexual selection. Journal of Comparative Physiology A187: 323-326

Supervision

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

Websites:
Personal page Joris Koene
the koene group