Entomological Society of America
St. Louis, Missouri
Effects of caste on Critical PO2 and flight metabolic rate in the bumble bee, Bombus impatiens
Poster #: D3102
Monday, November 18th, 9:00am-6:30pm
America’s Center- Exhibit Hall 1 & 2
Bombus impatiens are a social bumble bee species used in commercial pollination. Bumble bee queens overwinter underground. Underground burrows may be a hypoxic (low oxygen) environment, which could be detrimental to bees. Although many insects are tolerant of hypoxia, this is not known for B. impatiens. The tracheal system of B. impatiens workers is positively correlated with body size. However, queens have tracheal systems that are much smaller than would be expected for their large body size, suggesting that overwintering queens may have lower hypoxia tolerance than workers. To determine how queens and workers tolerate low oxygen, we measured the critical PO2. The critical PO2 is the oxygen level below which metabolic rate cannot be maintained. Critical PO2 was measured by exposing bees to decreasing levels of oxygen via respirometry during rest; flight metabolic rate was measured at different oxygen levels individually. Queens and workers did not have significantly different critical PO2 values either at rest or during flight. Together, these data suggest that the queens’ small tracheal system volume may not negatively affect their ability to tolerate hypoxia. Knowing that bumble bees are tolerant of hypoxia may help to use this in commercial storage, as has been successful in other bee species.
© Photo by Meghan Duda
Rikki Walter is a graduate student at North Dakota State University. Her undergraduate research was on metabolic rate and critical oxygen partial pressure in bumble bees. Join Rikki and her colleagues on November 18th at the Entomological Society of America (ESA) conference in St. Louis, Missouri. Click here for conference details.