The effect of environmental temperature on resting energy expenditure of Common Eastern Bumblebee, Bombus Impatiens
Zoë Perkins, Charles-Antoine Darveau
Department of Earth and Environmental Sciences, University of Ottawa
Zoë Perkins, Charles-Antoine Darveau
Department of Earth and Environmental Sciences, University of Ottawa
This study investigates the effect of temperature on the resting metabolic rate (RMR) of the bumblebee species, Bombus impatiens. The understanding towards a species’ capacity for thermal tolerance is necessary to predict how this species will respond and adapt to changing climatic conditions. Climate change possesses the increasing potential to alter global biodiversity as temperature fluctuations often result in negative consequences for species. Bees are no exception. As endothermic poikilotherms, bees exhibit some degree of thermoregulation, while being largely influenced by their surrounding environment. Unlike honeybees, bumblebees are less social and do not contribute to overall hive thermoregulation, rendering them more susceptible to changes in temperature. Often when bees are at rest, they enter a discontinuous gas exchange cycle (DGC) whereby energy consumption is typically low and stress tolerance is increased. During a DGC, CO2 is released through the controlled opening and closing of spiracles, creating “peaks” in CO2 production. Respirometry techniques were used in this study to calculate and compare average RMRs and respiratory patterns of bee individuals across three temperature treatments (15, 10, and 5 °C) and one control (25 °C). Carbon dioxide production rate (VCO2) was used as a unit of measurement and calculated using two different methods: 1. VCO2 produced by one bee individual undergoing a DGC; and 2. VCO2 produced by one bee individual at rest. Results suggest a steady decrease in RMR with decreasing temperatures. This implies a decrease in DGC “peaks” and duration with temperature. Percentage of bee individuals exhibiting no pattern of a DGC over the time period observed increases by more than 3-fold during the lowest temperature treatment (5 °C). It is therefore likely that the RMR of bumblebee species Bombus impatiens could be influenced by extreme low temperatures. As vital pollinators who contribute to the welfare of many agricultural commodities within our society, the wellbeing of bumblebees is a necessary factor influencing global food security.