Latitudinal cline in reproductive traits in the red flour beetle Tribolium castaneum

Abstract Several previous studies have reported geographic variation and/or latitudinal clines of morphological sexual characteristics, but there are few that consider reproductive traits not morphological. Here, we measured the proportion females fertilized by males, frequency failure in and number female copulations red flour beetle Tribolium castaneum collected from fields Japan to investigate relationship between latitude. Our results show substantial differences both sexes among field populations. We identified for females. Moreover, female, male, were correlated with body size. study suggests selection male varies latitude T. . Significance statement It has been established gradients frequently observed numerous animal species, which size is a prime example. Analogously, documented several indicating may be influenced latitude, although specific understanding thereof remains elusive. In this study, quantified analyzed their findings indicate mating efficacy was superior at lower than higher latitudes, no discernible gradient frequency. These imply selective pressure on males species stronger latitudes.