Seminar by Darko D. Cotoras "Evolution of the color polymorphisms on Theridiidae spiders from the temperate rainforest of southern South America"

Title: Evolution of the color polymorphisms on Theridiidae spiders from the temperate rainforest of southern South America

Speaker: Darko D. Cotoras

Affiliation: Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile

Department of Entomology, California Academy of Sciences

Color polymorphisms are an expression of morphological diversity with tight links with the ecology of the organisms. There are several cases of color polymorphism on spiders from the family Theridiidae. Here, I will present two cases of genera present along the temperate rain forest of Chile. First, the genus Selkirkiella is one of many geographically isolated and distantly related Theridiidae species across the world which share many characteristics (design, frequencies, inheritance mode, etc.) on their polymorphism. While similar ecological pressures and developmental constraints have been proposed as mechanisms to explain this parallel evolution, the way of how population variability is inherited through speciation events remains poorly understood. In order to answer this, we are working into reconstruct the evolutionary history of the color polymorphism on Selkirkiella. The second example is on the genus Kochiura, where closely related species with a huge color variation across several populations distributed on a large geographic area. What are the determinants of color variability? In other words, why not all the populations across species look the same? Here, the working hypothesis is that the color variability of each population is determined by a combination of genetic, ecological and historic factors. The results presented for both projects are research in progress. They will extend our understanding on the evolution of complex traits and update our knowledge on endemic genera from the Valdivian forest biodiversity hotspot.