Ross, L., Shuker, D.M., Pen, I., West, S.A., & Weissing, F.J. 2008 Genomic conflict over sex allocation in the mealybug Planococcus citri.. Proceedings of the XI International Symposium on Scale Insect Studies, Oeiras, Portugal, 24-27 September 2007. ISA Press Lisbon, Portugal 322 pp.

Notes: Genomic conflict is an important force shaping the evolution of numerous life history traits. Here we consider genomic conflict over sex allocation in the mealybug Planococcus citri. Genes expressed in males, females or in their endosymbiotic bacteria all have conflicting interests in the sex ratio of the offspring. Males favour a female- biased sex ratio, because due to their genetic system (paternal genome elimination), only their daughters pass on their genes. Females on the other hand may favour a male-biased sex ratio. This is because adult females form large immobile colonies, resulting in competition between related females. Mothers should therefore produce more male offspring, reducing competition between their daughters. Lastly, P. citri contain symbiotic bacteria. These bacteria are also selected to favour a female-biased sex ratio, as they are only transmitted via eggs. Here we test the sex allocation responses of females to different patterns of local resource competition among daughters and consider the role of male and bacterial genomes as a constraint on adaptive sex allocation by female mealybugs.