Experimental insight into the proximate causes of male persistence variation among two strains of the androdioecious Caenorhabditis elegans (Nematoda)

Viktoria Wegewitz,Adrian Streit,Hinrich Schulenburg

doi:10.1186/1472-6785-8-12

Viktoria Wegewitz, Adrian Streit + Show 1 more

Open Access

https://doi.org/10.1186/1472-6785-8-12

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Abstract

BackgroundIn the androdioecious nematode Caenorhabditis elegans virtually all progeny produced by hermaphrodite self-fertilization is hermaphrodite while 50% of the progeny that results from cross-fertilization by a male is male. In the standard laboratory wild type strain N2 males disappear rapidly from populations. This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856.ResultsWe determined the kinetics of the loss of males over time for multiple population sizes and wild isolates and found significant differences. We performed systematic inter- and intra-strain crosses with N2 and CB4856 and show that the males and the hermaphrodites contribute to the difference in male maintenance between these two strains. In particular, CB4856 males obtained a higher number of successful copulations than N2 males and sired correspondingly more cross-progeny. On the other hand, N2 hermaphrodites produced a higher number of self-progeny, both when singly mated and when not mated.ConclusionThese two differences have the potential to explain the observed variation in male persistence, since they should lead to a predominance of self-progeny (and thus hermaphrodites) in N2 and, at the same time, a high proportion of cross-progeny (and thus the presence of males as well as hermaphrodites) in CB4856.

Highlights

Compared with the dioecious species Caenorhabditis remanei, mating behaviour was severely compromised in the N2 strain, i.e. males often fail to find hermaphrodite mates, possibly due to limited production and/or degeneracy of the hermaphrodite's sex pheromone [[7,12] but see, [13,14]]. These results suggested that males represent evolutionary relics without any particular function, which are only still present, because of a relatively recent switch to hermaphroditism and selfing in the lineage leading to C. elegans [7]
In the second part we evaluate the possible reasons for the difference in male persistence between the two common laboratory strains N2 and CB4856
Our results indicate that CB4856 males are capable of mating successfully with more hermaphrodites than N2 males and that N2 hermaphrodites produced a higher number of selfprogeny even after mating

Summary

Introduction

In The Nematode Caenorhabditis elegans Edited by: Wood WB. In the androdioecious nematode Caenorhabditis elegans virtually all progeny produced by hermaphrodite self-fertilization is hermaphrodite while 50% of the progeny that results from cross-fertilization by a male is male. In the standard laboratory wild type strain N2 males disappear rapidly from populations. This is not the case in some other wild type isolates of C. elegans, among them the Hawaiian strain CB4856. The nematode Caenorhabditis elegans is a facultative hermaphrodite that reproduces either by virtue of self-fertilization or cross-breeding with a male (androdioecious reproductive system). Except for a very few males (around 0.2% in the standard laboratory strain N2) that arise spontaneously as the result of X chromosome non-disjunction, the entire self-progeny is hermaphroditic.

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