Meeting Abstract
Sexual dimorphism is often the result of condition-dependent expression of sexually selected traits, like animal weapons. Most commonly, larger males that developed under nutritionally rich conditions grow disproportionately bigger weapons than smaller individuals that developed under poor nutritional conditions. Meanwhile female homologous traits generally do not experience this developmental plasticity in such a way. But the degree of sexual dimorphism has also been attributed to abiotic factors, like temperature. And even though the connection between condition-dependence and sexual dimorphism is obvious, this connection has been ignored until recently. Here, we investigated the relationship between condition-dependence and sexual dimorphism using two ecologically relevant environmental factors, natural diet and temperature. We used the leaf-footed cactus bug Narnia femorata; the males of this sexually dimorphic species possess enlarge hind legs used in male-male contests. As expected diet had a major effect on all traits, but it was disproportionately stronger on hind leg traits (sexually selected weapons). Temperature had a significant effect on some traits, including hind leg traits. Furthermore, diet and temperature interacted to create treatment-specific differences between male and female phenotypes. This study highlights how natural variation of environmental factors can interact and cause the differential expression of morphological traits across environments.
