Wednesday, September 24, 3:30-4:30 pm, Room 1400 Memorial Student Center (MSC)
Ecological and environmental factors that affect reproduction in the honey bee
Abstract: Reproduction in eusocial insects is monopolized by one or a few individuals, while the remaining colony tasks are performed by the worker caste. This reproductive division of labor is exemplified by honey bees (Apis mellifera) in which a single, polyandrous queen is the sole colony member that lays fertilized eggs. Previous work has revealed that the developmental fate of honey bee queens is highly plastic, with queens raised in poor nutritional or environmental conditions exhibiting lower measures of reproductive potential compared to queens raised under healthier conditions. Over the last five years our research has focused on examining some of the biotic and environmental factors that affect honey bee reproductive quality, and ultimately, colony-wide phenotype and fitness. For instance, we have found that queens that develop from larvae that are fed differentially during early larval instars affect adult queen’s physiology, worker behavior, and colony productivity. More recently, we have found that queens and drones that develop in a beeswax environment contaminated with pesticides used by beekeepers in the control of the ectoparasitic mite Varroa destructor exhibit lower reproductive potential and survival compared to those that develop in a pesticide-free environment. Our studies provide evidence that in honey bees, queen and drone reproductive potential depends on the colony conditions present during their development. We also provide evidence that the reproductive quality of queens and drones directly affect several factors of a colony’s phenotype. As such, a honey bee colony may be seen as the ‘expanded phenotype’ of its queen (and her mates). Thus, while the colony may primarily serve as the unit of selection, the distinction between individual- and colony-level selection may actually be blurred. We will discuss our findings in the context of other factors that may influence reproductive health in honey bees as well as other eusocial insects pollinators that exhibit caste developmental plasticity and are exposed inadvertently to environmental conditions that synergistically affect colony phenotype and fitness.
About this speaker: Dr. Rangel leads the Honey Bee Lab and is responsible for developing a research program that focuses on solutions to problems facing the apiculture industry. She also teaches graduate and undergraduate courses in honey bee biology and plans to work with the industry leaders to develop specific hands-on training courses.
Wednesday, October 15, 3:30-4:30 pm, ILSB Auditorium
Functional traits, convergent evolution, and a periodic table of niches
Presented by Dr. Kirk Winemiller, Aquatic Ecology Lab, Department of Wildlife and Fisheries Sciences, Texas A&M University
Abstract: Ecology is often said to lack general theories sufficiently predictive for practical applications. Noting community ecology’s reinvigorated interest in functional traits, I will explore the feasibility of a periodic table of niches, an idea first proposed by Robert MacArthur. Pursuit of niche ordination schemes is already well underway, and more thought should be devoted to determining traits associated with fundamental niche dimensions and how these dimensions interact to determine fitness within different environmental settings. Consistent patterns of trait intercorrelation and patterns of convergent evolution make possible species ordination within a limited number of fundamental niche dimensions. Using tropical fish assemblage dataset, I will examine two basic approaches for creating periodic tables of niches: niche ordination within continuous gradient space, and niche classification according to discrete categories. Periodic tables of niches could make community ecology a more predictive science that enhances environmental and natural resource management.
Chagas disease ecology at the intersection of human, animal, and vector populations
Presented by Dr. Sarah Hamer, Department of Veterinary Integrative Biosciences, Texas A&M University College of Veterinary Medicine
Abstract: The maintenance of vector-borne zoonotic pathogens in nature is often sustained by cryptic transmission among wildlife reservoirs with occasional spillover to humans. I will present my lab’s research program on the ecology of Chagas disease, a significant heart disease and cause of death in humans and dogs across Latin America that is increasingly recognized in the southern United States. The disease is caused by infection with a protozoan parasite (Trypanosoma cruzi) that is spread by bloodfeeding Triatomine ‘kissing’ bugs. Our citizen science program is empowering the public and medical community and has resulted in the submission of over 1800 kissing bugs from across the southern states; these bugs are characterized by over 60% infection prevalence. We are comparing parasite strains that circulate among bugs and various wildlife species to those we have isolated from dogs that died of Chagas cardiomyopathy. In contrast to current media hype about invasion across the border, I will discuss the endemicity of the components of the Chagas pathosystem in the southern states.
Ecological speciation among herbivorous insect populations
Presented by Dr. Scott Egan, Department of Biosciences, Rice University
Abstract: Speciation describes the evolutionary process by which new biological species arise. Understanding the mechanisms contributing to this process is a fundamental question in evolutionary biology. One form of speciation, termed ecological speciation, describes the process by which ecologically based divergent selection between environments leads to the evolution of reproductive barriers between populations. Research on this topic is naturally interdisciplinary and I use a combination of approaches, including field experiments, observations of natural history, lab-based behavioral assays, and genetic and genomic techniques, to better understand how new species evolve in response to divergent selection. Using data from multiple study systems, including Cynipid gall wasps, Chrysomelid leaf beetles, and Tephritid fruit flies, I will present evidence of the critical and diverse role that ecologically driven divergent natural selection can play in the evolution and speciation of plant-feeding insects.
About this speaker: Dr. Egan is interested in the processes that promote or constrain the evolution of new biological species. Examples of his research include (1) understanding the role of adaptation via natural selection in the speciation process and (2) exploring the genomic architecture associated with and mediating the evolution of new species. This work requires a multidisciplinary approach integrating natural history, manipulative field experiments, behavioral observations, and population genetics and genomics. Related research interests include interdisciplinary research that harnesses genetic variation to address societal challenges, such as the rapid environmental detection of rare or invasive species.