Phenotype-dependent mate choice and the influence of mixed-morph lineage on the reproductive success of a polymorphic and aposematic moth

作者：Gordon Swanne P^*; Burdillat Sini; Mappes Johanna

来源：Evolutionary Ecology, 2018, 32(4): 427-441.

DOI：10.1007/s10682-018-9944-5

• Polymorphism
• Aposematism
• Mate choice
• Heterozygote advantage
• Sexual selection
• Wood tiger moth Arctia plantaginis

Polymorphic warning signals in aposematic organisms are puzzling because efficient predator learning should select for the most efficient warning colouration. Yet, there are many examples of polymorphic and aposematic organisms in nature. Here, we investigated whether perceived trade-offs between natural and sexual selection, combined with different degrees of morph lineage admixture, can maintain polymorphic yellow and white hindwing colouration in aposematic wood tiger moth males (Arctia plantaginis). Prior research in the system suggests that yellow males have better warning colouration against predators, whereas white male morphs have higher mating success. We performed a mating experiment where females were offered four males: two white and two yellow. One male from each colour came from (purely) monomorphic lines (i.e. including the same paternal colour for multiple generations), whereas one male from each colour were from mixed-morph (or hybrid) lineages. We then assessed whether phenotype (colour), lineage, or an interaction between the two, best affected mating success. Our results showed that although white hindwing coloured males tended to have overall better reproductive success, this was mainly due to the significantly higher mating and hatching success of mixed-morph compared to pure-line individuals. Notably, this suggests the advantage of mixed-morph lineage is limited to white individuals, while on the contrary yellow mixed lineage moths have a disadvantage, i.e. the lowest mating success. The latter also suggests a cost to reproductive success in producing the more efficient against predators yellow warning colouration, even when those individuals recently descend from a white hindwing coloured lineage. Heterozygote, or hybrid advantage, even when confined to only one morph, has been shown to promote polymorphism in some systems, therefore, our results point at the need to further examine genetic architecture and the role of mixed-morph lineages in understanding the maintenance of polymorphisms in nature.

• 出版日期2018-8