mate recognition system is the foundation of biological speciation in anurans. Ecological
and sexual selection have been suggested as major causes of male call
evolution. It is generally assumed that a significant fraction of variation in
male advertisement call has an underlying genetic basis and that there is a link
between key call attributes and fitness, yet these remain key, largely unproved
assertions regarding call evolution, and many factors contribute to diversity
of calls within a male chorus. Anurans advertisement calls are important in
studies of behavior, sexual selection, speciation, and phenology. In all of
these, understanding, heritability is prerequisite to understanding
evolutionary patterns and potential responses to selection. However, very few
studies have quantified heritability of advertisement calls in wild populations
of anurans, nor incorporate all factors know to influence call variation. In
this study, I try to estimate the heritability of anuran call attributes within
a calling assemblage of a temperate treefrog, Pseudacris crucifer, and quantify the relative contributions of
different factors: body size, age, calling temperature, and genetics. I use sonographic
analysis to assess call variation, skeletochronology to estimate age, and single
nucleotide polymorphisms (SNPs) markers to estimate the relatedness of calling
males. I use the animal model to evaluate all factors that may affect calls. By
simultaneously investigating the genetic basis of advertisement call attributes
as well as the effects of environmental factors, we will gain a better
understanding of call evolution and the potential for selection to drive
Meeting our global population’s food needs has involved intensive mechanization and centralization of food production. While this industrialization has allowed farmers to provide food for a burgeoning population, it has fundamentally changed the life cycles of domesticated animals in ways that create new and unknown threats to global food security. In my research I build mathematical models aimed at answering the question: how do modern agricultural management practices impact infectious disease burden, the risk of disease outbreaks and pathogen evolution? In this talk I will focus on recent changes to the poultry and the honeybee industries.
The central aim of my research is to understand how ecological and evolutionary factors combine to determine biodiversity patterns over large spatial and temporal scales. To do this, I use radiations of Anolis lizards on Caribbean islands as a natural experiment to test hypotheses about macroevolution, biogeography, and community ecology. In this seminar, I will ask how biogeographic patterns and community structure, both of which bear strong signatures of macroevolutionary history, are being reshaped by human activities in the Anthropocene. Specifically, I will ask how classic biogeographic factors (e.g., island area and isolation) and economic trade combine to predict species richness in invaded island faunas, and how natural climate gradients and recent land use patterns jointly predict the assembly of local communities within islands.
This week we welcome Aly Van Natto, Regan Cross, and Chris Eckert.
Dynamic dunes: science, stories, and shifting sands
Ecology is the process of turning nature into numbers, addressing theory-motivated questions with biological systems. Most of this takes place in unique ecosystems, and sometimes we’re so busy collecting data that we lose sight of the forest through the trees. Students in the Eckert lab have been working on the coastal dunes of California for more than 15 years. In this seminar, we take some time to pay homage to the ecosystem that has yielded so many great scientific opportunities.
Modular organisms (e.g. plants, fungi, algae) dominate terrestrial and aquatic ecosystems but our understanding of their ecology and evolution lags far behind that of unitary, multicellular organisms (most animals). Central concepts, such as fitness, are not easily applied to modular organisms for which “individuals” can be hard to identify, with further complications for organisms like clonal plants that can transmit somatic mutations to offspring. In this talk I will present a recently completed model of sexual fitness in modular organisms and describe a test of predictions from previous modeling efforts.
Living in an (elementally) imbalanced world: Is stoichiometry useful in understanding the structure and functioning of an arctic tundra ecosystem?
Humans are causing major perturbations in global biogeochemical cycles, especially carbon, nitrogen and phosphorus. These changes put ecosystems under considerable stress, making it critical to understand the mechanisms that underpin ecosystem structure and functioning. Ecological stoichiometry (elemental ratios) is a recent theoretical approach that is based on the realization that all organisms are made of the same essential elements, and therefore provides a mechanistic link from the cellular level all way up to the biosphere. In particular, plant stoichiometric homeostasis – the ability of a species to maintain a certain elemental composition despite variation in the elemental composition in the soil – may represent a useful complementary trait to other plant traits in understanding and predicting community structure. I investigated its applicability in arctic tundra ecosystems by determining homeostasis indices for seven common tundra vascular species. I then analyzed how these homeostatic values were related to key aspects of ecological performance, such as plant dominance. Overall, these results will evaluate the potential contribution of ecological stoichiometry to predicting the impacts of environmental changes on arctic tundra vegetation.
Resource partitioning through the seasons: a test of a competitive ability – cold tolerance trade-off among closely-related, seasonally breeding beetles
Understanding the factors that maintain and constrain biodiversity and species coexistence is a major goal in ecology. When coexisting species use similar resources, this leads to the question: Why doesn’t one species use all the resources to the exclusion of all others? Trade-offs may be key in preventing one species from dominating all resources in all environments, thus allowing multiple species to coexist. Such trade-offs may be widespread in nature and play an important role in maintaining local biodiversity, but remain poorly described and understood. In this seminar, I will present evidence of seasonal resource partitioning in closely-related coexisting burying beetles (Nicrophorus) and explore a potential competitive-ability – cold tolerance trade-off.