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

Several previous studies have reported geographic variation and/or latitudinal clines of morphological sexual characteristics, but there are few studies that consider reproductive traits that are not morphological. Here, we measured the proportion of females fertilized by males, frequency of reproductive failure in males, and number of female copulations of the red flour beetle Tribolium castaneum collected from fields in Japan to investigate the relationship between reproductive traits and latitude. Our results show substantial differences in the reproductive traits of both sexes among field populations. We identified latitudinal clines for reproductive traits in males, but not females. Moreover, female, but not male, reproductive traits were correlated with body size. Our study suggests that selection for male reproductive traits varies with latitude in T. castaneum.

The version of record of this article, first published in Behavioral Ecology and Sociobiology, is available online at Publisher’s website: http://dx.doi.org/10.1007/s00265-023-03359-x