Population genetPics of the wood frog, Rana sylvatica, and the spotted salamander, Ambystoma maculatum Jonathan Richardson, Forestry Graduate Student
We are investigating the population genetics of wood frog, Rana sylvatica, and spotted salamander, Ambystoma maculatum, populations throughout Connecticut and Massachusetts. This study is using landscape genetic techniques and analyses to understand the influence of landscape features on amphibian dispersal, and the demographic and evolutionary consequences of varying levels of gene flow. This project is part of Jonathan Richardson’s dissertation research (Yale School of Forestry and Environment Studies Ph.D.).
Comparative phylogeography and coevolution of host, parasite, and
vector in the Galápagos archipelago
The Galápagos Islands present an extraordinary opportunity to examine patterns of migration and diversification of organisms. The geology of
the islands is well understood and allows the timing and order of
species colonization patterns to be inferred. In addition, islands
differ in many ways, including size, habitat, and community
composition, and this provides a backdrop for examining how different
environments contribute to adaptation of various traits in radiating
species. In this project, we plan to build on our existing knowledge
of marine iguana evolutionary history by overlaying phylogeographic
patterns of Hepatozoon parasites, and their potential arthropod
vectors (mosquitoes, ticks). By examining the genetic patterns of host
(marine iguanas), vector, and parasite, we can derive a greater
understanding of how parasites disperse between populations. We also
plan to use genetic techniques to collect data on parasite prevalence
from all the major islands in order to determine how the ecology of
each island contributes to the level of parasitism observed. For
example, marine iguana populations differ in density, possibly due to
local variation in levels of marine productivity. Population density
could be one factor which impacts the ability of vectors to transmit
parasites. In addition, the proximity of islands can also influence
the ability of the host or vector to moved parasites between islands.
This project is being developed in conjunction with Scott Glaberman, a
postdoctoral associate in the lab, Henry Scott, a Master's student in
Forestry and Environmental Sciences program, as well as with
scientists from Leeds University, Acadia University, and the Galápagos
National Park.
Microgeographic variation in growth and development rates of wood frog populations Nisha Ligon, EEB Undergraduate Student
Nisha is studying microgeographic variation in growth and development rates of wood frog populations. Nisha has performed a common garden experiment to compare growth and development rates between individuals from ponds of varying temperature and canopy cover, and am now is using microsatellite analysis to look at the genetic connectivity of those populations.
Investigation of the Eliurus antsingy complex: Species boundaries and phylogeography Jean-Eric Rakotoarisoa, EEB Graduate student
The genus Eliurus is the most speciose among native Malagasy rodents. Unfortunately, very little is known about its evolutionary history and its taxonomy is problematic. This project focuses on a species complex within the genus, the E. antsingy complex, and has two main objectives: (1) to contribute to the elucidation of taxonomic issues and evolutionary relationships among these species; and (2) to investigate the effects of both historical and contemporary factors on the evolution of Eliurus species found in a biogeographical transition zone located in northeastern Madagascar. Findings from this study will provide additional information that would help design conservation plans for this endemic genius.
