Biology subjects

Woodard, S. H.

Publications and source records attributed to Woodard, S. H..

3 recordsLinked to original sources

bioRxiv2023

Advancing bee conservation in the US: gaps and opportunities in data collection and reporting

Bee conservation in the U.S. is currently hindered by challenges associated with assessing the status and trends of a diverse group of >3000 species, many of which are rare, endemic to small areas, and/or exhibit high inter-annual variation in population size. Fundamental information about the distribution of most species across space and time, thus, is lacking yet urgently needed to assess population status, guide conservation plans, and prioritize actions among species and geographies. Using wild bee data from two public data repositories representing the contiguous U.S., we evaluated the availability and sufficiency of data for use in species assessments of wild bees. We also examined the number of bee species recorded in each U.S. state and the proportion of species with recent records (2012-2021). Although efforts to monitor bees continue to grow, there remains a massive paucity of data. Exceedingly few records (0.04%) reported both sampling protocol and effort, greatly limiting the usefulness of the data. Few species or locations have adequate publicly available data to support analyses of population status or trends, and fewer than half of species have sufficient data to delineate geographic range. Despite an exponential increase in data submissions since the 2000s, only 47% of species were reported within the last decade, which may be driven by how data are collected, reported, and shared, or may reflect troubling patterns of local or large-scale declines and extirpations. Based on our analysis, we provide recommendations to improve the quality and quantity of data that can be used to detect, understand, and respond to changes in wild bee populations.

ecology↗

bioRxiv2022

Mountains as refugia: evidence from bumble bee brain transcriptomes

As anthropogenic change continues to impact global biodiversity, the importance of rapidly identifying biodiversity refugia cannot be overstated. In this study, we employed a molecular test of the hypothesis that mountains serve as refugia for bumble bees against anthropogenic stressors. To explore this hypothesis, we compared stress-related patterns of gene expression in the brains of wild, pollen-foraging bumble bees of two species, B. vosnesenskii and B. melanopygus, collected at different elevations throughout the Sierra Nevada Mountain range in California, USA. We found evidence that the expression of several immune and detoxification genes is associated with elevational differences. This suggests that bees are experiencing differential exposure to stressors along an elevational gradient, which is an important criterion for identifying refugia across dynamic and heterogenous environments. This study thus provides evidence that mountains may serve as refugia for bumble bees in response to anthropogenic stressors, as has been detected for many other organisms.

ecology↗

bioRxiv2020

What evolutionary processes maintain MHCIIβ diversity within and among populations of stickleback?

Major Histocompatibility Complex (MHC) genes encode for proteins that recognize foreign protein antigens to initiate T-cell mediated adaptive immune responses. They are often the most polymorphic genes in vertebrate genomes. How evolution maintains this diversity is still an unsettled issue. Three main hypotheses seek to explain the maintenance of MHC diversity by invoking pathogen-mediated selection: heterozygote advantage, frequency-dependent selection, and fluctuating selection across landscapes or through time. Here, we use a large-scale field parasite survey in a stickleback metapopulation to test predictions derived from each of these hypotheses. We identify over a thousand MHCII{beta} alleles and find that many of them covary positively or negatively with parasite load, suggesting that these genes contribute to resistance or susceptibility. However, despite our large sample-size, we find no evidence for the widely-cited stabilizing selection on MHC heterozygosity, in which individuals with an intermediate number of MHC alleles have the lowest parasite burden. Nor do we observe a rare-allele advantage, or widespread fluctuating selection across populations. In contrast, we find that MHC diversity is best predicted by neutral genome-wide heterozygosity and between-population genomic divergence, suggesting neutral processes are important in shaping the pattern of metapopulation MHC diversity. Thus, although MHCII{beta} is highly diverse and relevant to the type and intensity of macroparasite infection in these populations of stickleback, the main models of MHC evolution still provide little explanatory power in this system.

evolutionary biology↗