Greg Grether is a professor of Ecology and Evolutionary Biology and a fellow of the Animal Behavior Society.
Greg and members of his lab have worked on a diverse assortment of animals in a wide range of habitats. The common thread through all of the projects is the role of animal behavior in ecological and evolutionary processes. Some projects have an applied conservation focus while others are aimed purely at advancing knowledge of the natural world.
Greg received his PhD from UC Davis in 1995, was an NSF postdoctoral fellow at UC Santa Barbara in 1996-98, and joined the UCLA faculty in 1999. His research is supported primarily by the National Science Foundation. He teaches undergraduate and graduate courses in evolutionary biology and animal behavior and a field course in behavioral ecology through the Field Biology Quarter program.
Graduate Students and Post docs
María Beatriz Cabezas Castillo completed her master’s degree in Ecology and Evolutionary Biology in June 2017 and is currently a post-master’s researcher in the Grether lab. She is interested in animal behavior, and particularly in the mating and territorial behavior of damselflies in the genus Hetaerina genus. In one of her current projects, she is examining whether damselflies have the ability to discriminate between territorial neighbors and non-neighbors, and if so, whether the dear enemy phenomenon or nasty neighbor effect governs how territorial males respond to intruders.
Rachel Chock is a PhD candidate in Ecology and Evolutionary Biology and is co-advised by Greg Grether and Debra Shier. Rachel is interested in applying behavioral ecology research to conservation. Her dissertation research focuses on Pacific pocket mice, an endangered species found only in Southern California, and how they compete and coexist with other rodents in their community. She is studying direct interactions between pocket mice and four other rodent species, competition between the species for food resources, and how each species differs in their use of their shared habitat. The results will be used to select appropriate areas for reintroductions of captive bred Pacific pocket mice, releasing them into communities where they will have the best chance for survival and reproduction.
Robert Cooper is a PhD candidate in Ecology and Evolutionary Biology, co-advised by Greg Grether and Brad Shaffer. He is interested in how human disturbance influences native species in California, specifically in reptiles and amphibians. He is investigating this dynamic in the California tiger salamander, which has been rapidly hybridizing with an introduced salamander. Robert is using differential gene expression to identify differences in thermal tolerance between the native, invasive and hybrid salamanders, and the genetic mechanisms that drive them. He is also exploring the use of pond hydroperiod as a management tool to slow, stop, or even reverse the spread of non-native alleles through the landscape.
Madeline Cowen is a Master’s student in Ecology and Evolutionary Biology, advised by Greg Grether. She has previously studied behavioral ecology of red-backed fairy-wrens and breeding and dispersal patterns in California scrub-jays. Her current research explores her interest in understanding how competition and behavioral interactions between species relate to trait evolution and biodiversity. She is conducting a phylogenetic comparative study of North American songbirds to identify traits that predict territoriality between species in this diverse order of birds.
Jonathan Drury is a post-doctoral researcher in the Grether lab. His research aims to test hypotheses about the role of interspecific competition in driving trait evolution at multiple scales. To do this, he combines field research on rubyspot damselflies with the development and application of cutting-edge phylogenetic methods. For more information, visit his website.
Brigit Harvey is a Master’s student in Ecology and Evolutionary Biology, co-advised by Greg Grether and Debra Shier. Her research focuses on combining Behavioral Ecology and Conservation Biology to improve the foraging options of the critically endangered Pacific pocket mouse (Perognathus longimembris pacificus) when reintroduced into the wild. Invasive species (especially grasses) are considered a threat to the biodiversity of a landscape because they displace the presence of native species and can eliminate historic food sources. Brigit is investigating whether granivorous Pacific pocket mice can be trained to consume the seeds of invasive plant species found across the Orange and San Diego County landscape to increase their foraging options when released back into the wild. She also seeks to convert the Pacific pocket mouse’s captive diet to a fully native diet at the breeding facility funded by the San Diego Zoo Institute for Conservation and Research.
Shawn McEachin is a PhD student in Ecology and Evolutionary Biology advised by Greg Grether. He is interested in how species select the habitats they occupy and how interspecific competition affects habitat use. Specifically, he studies species of rubyspot damselflies that occur in the same location and compete with each other. Male rubyspots defend their territories against males of their own species and against other rubyspot species that have similar wing coloration. Is it possible that one species can exclude another species from its preferred habitat? Is it possible to reduce interspecific competition by using different parts of the habitat? To answer these questions, Shawn carries out various experiments and observations throughout Costa Rica collecting data on damselfly behavior and habitat use. His dissertation will shed light on the processes involved in habitat selection and how competition affects habitat use.
Elizabeth Reid-Wainscoat is a Master’s student in Ecology and Evolutionary Biology. She is co-advised by Greg Grether and Debra Shier. Elizabeth collaborates with the Tasmanian Government Department of the Environment and Energy on research supporting recovery of the Tasmanian devil.
The Tasmanian devil is a carnivorous marsupial that has suffered dramatic population decline in the past 20 years due to a contagious fatal cancer called Devil Facial Tumor Disease or DFTD. Due to this devastating disease, the Tasmanian devil is now endangered. To protect against possible extinction researchers decided to collect some of the remaining healthy individuals from the wild and start a captive breeding program. The goal was to help counteract the effects of this disease by supplementing the wild population with healthy, vaccinated individuals from the captive population. However, this strategy of reintroducing captive animals to the wild has proven very difficult with a variety of other species. Specifically, it is very hard to simulate the wild environment in captivity and thus captive animals often do not have the skills needed to survive. In addition, the stress of being released into a novel environment can cause the animals to disperse immediately from the area into environments that are potentially more dangerous and less suitable for their ecological needs.
To address these issues a collaborative project was developed by the San Diego Institute for Conservation Research and the Save the Tasmanian Devil Program to study the behavioral ecology of the Tasmanian devil. Although Tasmanian devils are considered solitary, it is widely known that they use latrine sites, or communal areas of scat and urine deposition, within any given population. This means that although they might not interact physically, they may be using scent cues to communicate which individuals are in an area. This is interesting because although they do not defend territories, there is the potential that they are more familiar with the individuals within their population because of the scent cues they leave at known latrine sites. This could mean that introducing new individuals into a population could disrupt the social system in place and could cause heightened levels of aggression between resident devils and the new individuals entering the population. This is especially problematic because DFTD is contagious so if infected devils are biting healthy devils the disease is going to spread through the population more quickly.
Previous studies have shown that familiarization of individuals can increase survival and decrease dispersal post-release. Thus, this study is testing the effects of familiarization via scent cues between release candidates and resident devils prior to release. We hope to encourage social integration between the two groups of Tasmanian devils and decrease dispersal from the release site to ensure the reintroduction efforts successfully increase wild Tasmanian devil populations. Specifically, we are identifying the level of specificity that we can expect the Tasmanian devils to be communicating with their scent cues. This involves testing their scent gland secretions as well as their scat for specific chemical components that could be gender and/or individually specific. If we can show that there are detectable differences between individuals then this will support preliminary behavioral findings that suggest they are able to discriminate between individuals. We can then test the impact of familiarization on aggression levels to determine if familiarization could potentially reduce disease transmission rates. Finally, we want to test what effect familiarization has on survival post-release to determine the most effective strategies to re-establishing the Tasmanian devil wild population.