2010/11/10 by Karim Vahed, Darren J. Parker, James Gilbert · 1 citation
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Animal Behavior and Reproduction #Plant and animal studies #Insect and Arachnid Ecology and Behavior
paper · doi:10.1098/rsbl.2010.0840
openalex publication_date 2010/11/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/08
While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate (ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate.