VARIABLE RESPONSE TO TEMPERATURE BETWEEN INVASIVE DAPHNIA LUMHOLTZI CLONES ESTABLISHED AT DIFFERENT LATITUDES IN NORTH AMERICA
Daphnia lumholtzi, a freshwater zooplankter, native to Africa, Australia, and Southwest Asia was found in reservoirs in the Southern US in 1991, and has since rapidly expanded its range to as far north as Lake Superior. We address the hypothesis that adaptive evolution and selection for tolerance of lower temperatures has occurred in populations of D. lumholtzi, facilitating its northward range expansion. To test this, Daphnia lumholtzi clones, including one from Holt Lake AL, and three from Lighthouse Point, Lake St Clair, Canada were used to quantify fitness response to temperature. We reared them at 3 temperature treatments: 15, 20, and 25 C, and then we measured fitness using the proxy of reproductive success. We measured age at maturation, and quantified and preserved the first three reproductive events. We then used the Euler method to calculate r.
Bana Kabalan (Primary Presenter/Author), Wayne State University, firstname.lastname@example.org;
Alison Rifenburgh (Co-Presenter/Co-Author), Wayne State University, email@example.com;