珈蟌的種化過程與機制-翅型分化與臨域分佈之角色

Speciation is of pivotal importance in ecology and evolution. Divergence between evolving populations could be caused by several potential mechanisms, including allopatric isolation, ecological separation, pre-mating isolation by behavioral adaptation, post-mating isolation through genetic/cytoplasmic incompatibility, and sexual selection. We investigate the processes and mechanisms of speciation in two parapatrically distributed sister damselflies in Taiwan, the northern Psolodesmus mandarinus mandarinus and central/southern P. m. dorothea, with recent divergent wing forms. This study aims to test the following specific hypotheses/predictions derived from ecological speciation and sexual selection: (1) Is the distribution of P. mandarinus correlated with environmental/ecological factors? (2) Do the wing variations (pigmentation and shape) between- and within- each P. mandarinus subspecies associated with environmental factors and species-specific distributions? (3) Is there any genetic introgression/gene flow between these two subspecies in the contact zone? And if so, what is the pattern of gene flow (direction and level)? (4) Directly evaluate the causality of sexual selection and (5) ecological speciation using both mate choice/breeding trials and common garden/reciprocal transplant experiments. For the third year (2019/08-2020/07), we analyzed the patterns of spatial and temporal allocation of male reproductive tactics in relation to mating success. The two sites (Fusan and L showed similar pattern of distribution of males using alternative tactics, but the switching males of of Lianhuachi tended to stay longer between sites than that of Fusan.