2nd Place: Using frass to estimate lepidopteran biodiversity and biomass across an urban gradient

Monday, November 14, 2022

9:24 AM – 9:36 AM PT

Location: Vancouver Convention Centre, Meeting Room 207

Presenting Author(s)

Lillian Khristina Hendrick

Graduate Student
University of Florida
Gainesville, Florida

Co-Author(s)

Michael W. Belitz

Graduate Student
Florida Museum of Natural History
Gainesville, Florida
AS

Asia Sawyer

Florida Museum of Natural History
Gainesville, Florida
RG

Robert Guralnick

University of Florida Research Foundation Professor
Florida Museum of Natural History
Gainesville, Florida

Continuing urbanization is one of the most intensive and disruptive drivers of insect diversity and distribution change,due to habitat loss and fragmentation, urban heat island effects, and artificial light at night (ALAN). Moths, and other night flying, light attracted insects may be even more impacted by urbanization than diurnal insects due to ALAN disrupting moth behavior and physiology. Unfortunately, understanding the impacts of urbanization on light attracted insects remains challenging because sampling typically relies on light traps that collect adult life stages. Such approaches, while important, tend to be biased towards larger and more attractive species and miss crucial information about other life stages. Here, we examine the effects of urbanization on lepidopteran diversity and abundance by passively collecting caterpillar frass once a week over 52 weeks along an urban-to-rural gradient. We are in the process of extracting DNA from frass for biweekly samples and using metabarcoding approaches with lepidopteran specific genes to characterize caterpillar community assemblage. Our preliminary results show weak evidence that overall caterpillar biomass decreases as urbanization increases. However, we expect caterpillar biomass in urban areas to be driven by a few urban-thriving species, and therefore, caterpillar diversity will decrease strongly as urbanization increases, and specifically specialist species with fewer host plants and less dispersal ability to be found more commonly in rural sites. Our caterpillar frass approach will help to elucidate how lepidopteran communities will change over time as urbanization increases.