Jennifer Lee Rose Hills
Understanding Coexistence of the Hawaiian Tetragnatha Spiders
Understanding niche differentiation is fundamental for comprehending the complicated process of adaptive radiation, a process characterized by the rapid formation of many ecologically different species from a single ancestor. However, the way in which niche differentiation is achieved during the early stage of adaptive radiation is still highly debated among evolutionary biologists. On the one hand, through the process of character displacement, natural selection could facilitate differentiation and diversification between closely related species where they co-occur with no need for prior niche differentiation at the time of secondary contact. Alternatively, enough niche differentiation between species can be achieved in isolation, before range overlap, facilitating coexistence and reducing the chance for competitive exclusion. Therefore, the goal of this project is to conduct a comparative analysis between sympatric and allopatric populations of the two species of the green ecomorphs of Hawaiian Tetragnatha spiny-leg spiders (T. waikamoi and T. brevignatha) to answer how these species can coexist with one another based on different dimensions of niches. Using carbon and nitrogen isotopic signatures of the spiders tissues, their body size measurements, and gut content, in sites where the taxa do and do not co-occur, will help address this question. Therefore, this study will allow insights into the Hawaiian spiny-leg spiders diversification patterns and the mechanisms driving adaptive radiation.