Female mate choice in relation to heterozygosity in Tribolium castaneum

Abstract

Female mate choice, both before and after copulation, is pervasive among insect species. It is often hypothesized that females would preferentially mate with males that are genetically dissimilar to promote the genetic variability of the offspring. We used various strains of red flour beetle, Tribolium castaneum, and tested the effect of male and female genetic backgrounds on precopulatory and post-copulatory female mate choice. Simultaneous mate choice experiments using previously well established pheromone assays did not detect female preference for males of different strains. Post-copulatory female mate choice was examined through paternity analysis. Two parameters were used to measure post-copulatory female mate choice, including male defence capacity (P 1 , proportion of offspring sired by the first male when a female mated with two males consecutively) and offence capacity (P 2 , proportion of offspring sired by the second of two males to mate with a female). When female and male beetle strains were same, defence capacity was significantly higher than when female and male strains were different. However, such a pattern was not observed for offence capacity. The results suggest that female precopulatory mate choice is not affected by genetic background, but the outcome of postcopulatory processes depends on the genetic background of male and female beetles.

Female influence over offspring paternity in the red flour beetleTribolium castaneum

“…Lewis & Austad (1990) demonstrated consistent differences in second male sperm precedence (P 2 ) among T. castaneum male pairs. Recent studies showing that male strains differ in P 2 (Bernasconi & Keller 2001;Pai & Yan 2002) provide further evidence supporting male influence over fertilization success. Male fertilization success has also been found to depend upon interactions between particular male and female genotypes (Pai & Yan 2002;Nilsson et al 2003).…”

“…Recent studies showing that male strains differ in P 2 (Bernasconi & Keller 2001;Pai & Yan 2002) provide further evidence supporting male influence over fertilization success. Male fertilization success has also been found to depend upon interactions between particular male and female genotypes (Pai & Yan 2002;Nilsson et al 2003). Tribolium castaneum copulatory behaviour, which includes male leg-rubbing and female quiescence (Bloch Qazi 2003), represents one arena for such interactions.…”

Strain-specific priming of resistance in the red flour beetle, Tribolium castaneum

“…Recently, T. castaneum has been further developed into a model system for embryonic development and pesticide resistance (Lorenzen et al 2005;, population genetics (Zhong et al 2004;Demuth & Wade 2007), mate choice (Bernasconi & Keller 2001;Pai & Yan 2002;Pai et al 2007;Pai & Bernasconi 2008) and for the study of host-parasite coevolution (Pai & Yan 2003;Fischer & Schmid-Hempel 2005). As its genome sequence has been completed, it is likely that other fields of biology will adopt this model system as well (Richards et al 2008; http://www.hgsc.bcm.tmc.edu/projects/tribolium/ ).…”

Variation in polyandry and its fitness consequences among populations of the red flour beetle, Tribolium castaneum

“…TIW1 and PRUZ individuals were paired with same-strain partners whereas NDG11 individuals were paired with cSM b/b beetles due to unavailability of same-strain beetles. Mating partners of TIW1 and PRUZ were marked with a green marker to facilitate separation of males from females (Pai and Yan 2002b) whereas mating partners of NDG11 beetles had a black body color that facilitated separation of males and females. Beetles used in an experiment (each strain) were of comparable age.…”