Bateman in Nature

#posted by Maren Wellenreuther

Dear all,
next week we will revisit a paper in Science that we discussed in a previous lab meeting this year: Bateman in Nature: Predation on Offspring Reduces the Potential for Sexual Selection by John Byers and Stacey Dunn. In the paper the authors state 'We found no evidence that random effects skewed male mating success; however, substantial yearly variation in the Bateman slope due to predation on fawns was evident. These results support the validity of the Bateman relationship, yet they also demonstrate that environmental or extrinsic influences can limit the potential for sexual selection'. 

 
Fly guy: Angus John Bateman used Drosophila to study the benefits of promiscuity.

This month a comment was published in Science and three key criticisms against the paper are raised 1) their nonstandard calculation of Bateman slopes;
2) their assertion that random processes do not influence reproductive success;
3) and the statistically unjustifiable use of 6 variables to explain just 10 observations.

Erik also suggested some additional reading, namely a TREE paper by Schaerer, Rowe and Arnquist about Anisogamy, chance and the evolution of sex roles


Lets talk about Batemans principles and related issues in greater depth at the next lab meeting, May the 14th 10:30 at Argumentet. I will bring some fika. 

Below are the two abstracts

Comment on “Bateman in Nature: Predation on Offspring Reduces the Potential for Sexual Selection”
Steven A. Ramm, Rudy M. Jonker, Klaus Reinhold, Tamás Székely, Fritz Trillmich,Tim Schmoll, Holger Schielzeth and Robert P. Freckleton
Byers and Dunn’s (Reports, 9 November 2012, p.802) conclusion that predation constrains sexual selection is problematic for three reasons: their nonstandard calculation of Bateman slopes; their assertion that random processes do not influence reproductive success; and the statistically unjustifiable use of 6 variables to explain just 10 observations.

Anisogamy, chance and the evolution of sex roles
Lukas Schärer,Locke Rowe and Göran Arnqvist
Recently, several authors have challenged the view that anisogamy, the defining feature of the sexes, is an important determinant of the evolution of sex roles. Sex roles are instead suggested to result from chance, or from non-heritable differences in life histories of females and males. Here, we take issue with these ideas. We note that random processes alone cannot cause consistent differences between the sexes, and that those differences between the sexes in life histories that affect the sex roles are themselves the result of sex-specific selection that can ultimately be traced back to anisogamy. To understand sex roles, one should ask how environmental variation and female–male coevolution cause variation in sex-specific selection in the light of anisogamy.