Assessing Thermal Tolerance of Infected and Uninfected Bombus impatiens to a Variable Thermal Environment

Presenter

Micah Lohr

Campus

UMass Amherst

Sponsor

Jennifer VanWyk, Department of Biology, UMass Amherst

Schedule

Session 3, 1:30 PM - 2:15 PM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A46, Campus Center Auditorium, Row 3 (A41-A60) [Poster Location Map]

Abstract

In insect species such as the common eastern bumble bee, Bombus impatiens, the relationships between body size, temperature, and disease are closely intertwined. Given the significant selection pressure that the latter two of these stressors impose, it is critically important to understand how rising temperatures and increased temperature variation associated with climate change will impact species who carry out critical ecological services. This work assesses the ecophysiology of B. impatiens in a variable thermal environment. Specifically, I compared the thermoregulation, behavior, and respiration of bumble bees when uninfected versus infected with a sublethal intestinal trypanosome, Crithidia bombi. Using a thermally controlled chamber, I measured thoracic body temperature, thermoregulatory behavior, and respiration rates in infected and uninfected B. impatiens workers from 24 to 36 ºC. I found a significant interactive effect of infection status and body size on thermoregulation such that in uninfected bees, there is a positive relationship between body size and the difference between ambient and core body temperature; however, in infected bees, there was no significant difference in thermoregulation based on size. Furthermore, the likelihood of an individual fanning– a physiological adaptation to heat stress– increased at higher temperatures regardless of infection. Finally, I found that while there were no significant differences in respiration based on infection status, the respiration rate of infected replicates demonstrated a negative relationship with infection intensity. Obtaining this fine-scale understanding of interacting stressors will inform us of the outcomes for important pollinator species with respect to global climate change.

Keywords

ecophysiology, bumble bees , disease ecology, thermal stress , climate change

Research Area

Biological Organisms

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