Efecte de l’ambient en la plasticitat fenotípica de la gambúsia (Gambusia holbrooki)

Abstract

Exotic species pose a serious threat to the conservation of native species and natural ecosystems; they are one of the main components of global change. Of special attention is the mosquitofish (Gambusia holbrooki), considered as one of the 100 worst invasive species worldwide. It was introduced to the Iberian Peninsula for biological control of mosquito larvae (i.e. to fight against malaria) in 1921. One of the characteristics that surely explains the great invasive success of the mosquitofish is its phenotypic plasticity, since it allows the ecological niche to expand, especially after a process of migration, colonization or disturbance. However, there are very few studies that focus on phenotypic plasticity or morphometry in the context of biological invasions, and the information available on shrimp is practically nil. For this reason, the aim of this work is to study the morphological changes or phenotypic plasticity of the shrimp in two different environmental conditions. The individuals were captured using different capture techniques (ganglins and the “salabre”), photographed and analyzed with the help of TPS and R software. The condition analysis showed significant differences between the two capture sites, with an increase in condition in Riet Vell (pond) for both males and females. In addition, morphological changes were observed in relation to the place of capture. The main changes were located in the area of the trunk of the caudal peduncle and mouth. The individuals captured in the river showed a greater proportion of the caudal area, while those captured in Riet Vell showed a mouth in a higher position. These changes can be explained by the differences in hydrology and availability of prey in the two environments