Entomological Society of America

Upcoming Talk by Kayla Earls

St. Louis, Missouri

Parental thermal history influences offspring characteristics
Monday, November 18th, 10:20am-10:30am
America’s Center – Room 267


During development, Megachile rotundatamay experience sudden, low temperature stress due to the environment or from agricultural practices to delay development. Although short-term exposure to low temperatures does not increase mortality in M. rotundata, previous research discovered sub-lethal effects. However, the lasting impacts of short-term exposure to low temperature stress on reproduction and future offspring is unknown. In this study, we tested the hypothesis that low temperature stress reduces fitness. Developing pupae were interrupted with either a constant (STR) or fluctuating (FTR) low temperature treatment for one week and then returned to 29°C to resume development. After adults emerged, 20 marked females and 10 males were placed in field tents in an alfalfa field. Bees were monitored for 3 weeks, and fitness and offspring characteristics were measured, including number of brood cells, offspring viability, dry weight, sex ratios, and diapause incidence. Bees exposed to low temperature treatments did not have a reduction in the number of offspring; however, brood cells created by STR-treated females had a higher proportion of viable offspring. Treated females did not alter the sex ratio of their offspring, but their investment in offspring differed with STR-females producing larger offspring. Offspring from STR-females weighed more than offspring from control females and FTR-females. Interestingly, offspring from FTR-females were significantly more likely to enter diapause, which suggests mothers are interpreting their environmental conditions differently. This is the first study to evaluate how low temperature stress during development affects future field performance, fitness, and offspring characteristics.

Join Kayla and her colleagues on November 18th at the Entomological Society of America (ESA) conference in St. Louis, Missouri. Click here for conference details.

© Photo by Meghan Duda


Kayla is a Ph.D. Candidate at North Dakota State University. Her research focus is how various types of environmental stressors affect reproduction in the solitary bee, Megachile rotundata. Some environmental stressors include low temperature stress during development, suboptimal environmental conditions that affect flight, and resource diversity. A single female bee is responsible for producing offspring, nest building and providing food for the offspring, which requires many steps that may be disrupted if the female is or has experienced a stressor. Megachile rotundata is the most managed solitary bee, however, farmers experience low return rates in the United States. Understanding the driving forces of reproductive decline is essential to mending this problem. Read more about Kayla HERE.

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