Evolutionary biologist Mercedes Burns

Burns, an assistant professor of biological sciences, will discuss "Reproductive Diversity and Sexual Conflict: Opilionid (Daddy-LongLegs or Harvestmen) Mating from the Female Perspective," when the UC Davis Department of Entomology and Nematology hosts her seminar at 4:10 p.m., Wednesday, Feb. 19 in Room 122 of Briggs Hall.

Harvesters or "daddy-longlegs" belong to the "ancient arachnid order Opiliones, which includes spiders, scorpions, mites and ticks," she says. "Although harvesters are often mistaken for spiders, they are very different! Harvesters (Opiliones) and spiders (Araneae) form separate branches in the arachnid tree of life. Harvesters do not have fangs, nor do they make venom or silk!"

"Sexual reproduction may pose myriad short-term costs to individuals through sexual conflict or the disruption of beneficial allelic combinations," Burns writes in her abstract. "Despite these costs, sexual reproduction is nearly ubiquitous in animal systems. To better understand the factors responsible for maintaining sex, study of alternative reproductive systems is necessary. We use daddy-longlegs or harvestmen (Arachnida: Opiliones) to understand how sexual conflict and post-copulatory mechanisms drive reproductive trait evolution. I will describe recent projects in my laboratory focusing on facultative asexuality and female reproductive morphological diversity in two groups of temperate harvestmen species from the United States and Japan."

The Burns Lab, she says, "studies the evolutionary and ecological mechanisms that contribute to sexual conflict in animal mating systems. We are interested in how demography, environmental factors, and evolutionary selective pressures influence reproductive morphology, genitalic function, mating behaviors, and holistic mating systems, especially in the leiobunine opilionids — a.k.a. harvesters, harvestpeople or 'daddy-long-legs.' We combine macroevolutionary and population-level approaches to understanding the biodiversity of arthropods, incorporating next-generation genomic sequencing, functional morphology, bioinformatics, and cytological methods into our toolkit. Current projects are focused on species groups in the United States and Japan with intriguing reproductive traits: parthenogenesis, sex ratio bias, reproductive armaments, and potential reproductive endosymbionts."

Burns holds a bachelor's degree in biology, awarded in 2006 from Macalester College, St. Paul, Minn., and a doctorate in behavior, ecology, evolution and systematics, awarded in 2014 from the University of Maryland, College Park. She accepted her current position in the fall of 2017 after completing a National Science Foundation postdoctoral fellowship in biology. She studied Japanese leiobunine harvestmen in Japan.

Read her research on Population Genomics and Geographical Parthenogenesis in Japanese Harvestmen (Opiliones, Sclerosomatidae), published in 2017 in the journal Ecology and Evolution.