Workshop / Seminar:EEB Prelim Seminar Series - Variation and Plasticity: Investigating the evolutionary history of migratory variation and seasonal phenotypic plasticity in the butterfly genus Danaus
2025-04-21 15:00 - 16:00 (America/Detroit) | Biological Sciences Building - 1010
Seminar Preview: The annual migration of the monarch butterfly spans over 4,000 km and facilitates the aggregation of millions of individual butterflies in south-central Mexico each winter. The monarch migratory syndrome is complex, integrating behavior, morphology, and physiology in an environmentally sensitive manner. Underlying this syndrome is an expansive genetic suite encompassing over 500 genes, as well as a significant capacity for seasonally-sensitive phenotypic plasticity. The evolutionary histories of this genetic suite and capacity for seasonal plasticity remain largely unknown beyond within-monarch assessments.
Monarch migration is an emerging model for testing broader hypotheses about the evolution of animal migration, complex traits, and the role of plasticity in adaptive evolution. A clearer understanding of how this spectacular phenomenon has emerged within just the past 20,000 years is necessary to better contextualize evolutionary inferences drawn from this model. My dissertation research will focus on characterizing patterns of seasonal plasticity as well as migratory genetic and phenotypic variation within the butterfly genus Danaus. This work integrates comparative approaches in phylogenomics and developmental genetics to generate insights into how key features of the monarch migratory syndrome have evolved within the genus.

Workshop / Seminar:GLNT: Near-center derivatives and arithmetic 1-cycles
2025-04-21 15:00 - 17:00 | East Hall - 3088
Abstract:

Theta series for lattices count lattice vectors of fixed norm. Such theta series give some of the first examples of automorphic forms.

It is possible to form "theta series" in other geometric contexts, e.g. for counting problems involving abelian varieties.
It is expected that these theta series again have additional automorphic symmetry.

I will explain some “near-central” instances of an arithmetic Siegel--Weil formula from Kudla’s program. These "geometrize" the classical Siegel--Weil formulas, on lattice and lattice vector counting via Eisenstein series.

At these near-central points of functional symmetry, we observe that both the "leading" special value (complex volumes) and the "subleading" first derivative (arithmetic volume) simultaneously have geometric meaning.

The key input is a new "limit phenomenon" relating positive characteristic intersection numbers and heights in mixed characteristic, as well as its automorphic counterpart.
