ICE Network Fargo

Size constrains oxygen delivery capacity within but not between bumble bee castes in Bombus impatiens

Rikki Walter, Joseph. P. Rinehart, Michael E. Dillon, and Kendra. J. Greenlee Abstract Bumble bees are eusocial, with distinct worker and queen castes that vary strikingly in size and life-history. The smaller workers rely on energetically-demanding foraging flights to collect resources for rearing brood. Queens can be 3 to 4 times larger than workers, flying…

A dose of experimental hormesis: When mild stress protects and improves animal performance

Raymond Berry, III and Giancarlo López-Martínez Abstract The adaptive response characterized by a biphasic curve is known as hormesis. In a hormesis framework, exposure to low doses leads to protective and beneficial responses while exposures to high doses are damaging and detrimental. Comparative physiologists have studied hormesis for over a century, but our understanding of…

Adaptation to the abiotic environment in insects: the influence of variability on ecophysiology and evolutionary genomics

Michael E Dillon, Jeffrey D Lozier Abstract Advances in tools to gather environmental, phenotypic, and molecular data have accelerated our ability to detect abiotic drivers of variation across the genome-to-phenome spectrum in model and non-model insects. However, differences in the spatial and temporal resolution of these data sets may create gaps in our understanding of…

Fluctuating thermal regimes prevent chill injury but do not change patterns of oxidative stress in the alfalfa leafcutting bee, Megachile rotundata

Alex S Torson, George D Yocum, Joseph P Rinehart, Sean A Nash, Julia H Bowsher Abstract In insects, prolonged exposure to unseasonably low temperatures can lead to detrimental physiological effects known as chill injury. Changes to active and passive transport across epithelia during chilling likely drive the collapse of ion gradients, metabolic imbalance and potentially…

Anoxia hormesis improves performance and longevity at the expense of fitness in a classic life history trade-off

Alyssa M.De La Torre, Giancarlo López-Martínez Abstract Hormesis occurs as a result of biphasic dose relationship resulting in stimulatory responses at low doses and inhibitory ones at high doses. In this framework, environmental factors are often studied to understand how this exposure benefits the animal. In the current study we used anoxia, the total absence…

Anoxia elicits the strongest stimulatory protective response in insect low-oxygen hormesis

Jacob B.Campbell, Giancarlo López-Martínez Published: March, 2022 Abstract The manipulation of oxygen to trigger the stimulatory response known as hormesis is an area of interest in insects that was born almost fifty years ago. Varying low-oxygen treatments have been investigated many times since with differing responses found; some hormetic/some harmful. In this review, we summarize…

Phat Queens Emerge Fashionably Late: Body Size and Condition Predict Timing of Spring Emergence for Queen Bumble Bees

Ellen Keaveny, Michael Dillon Published: September 24, 2022 Abstract For insects, the timing of many life history events (phenology) depends on temperature cues. Body size is a critical mediator of insect responses to temperature, so may also influence phenology. The determinants of spring emergence of bumble bee queens are not well understood, but body size…

Supercooling points of freeze-avoiding bumble bees vary with caste and queen life stage

Keaveny, E.C., Waybright, S.A., Rusch, T.W., and M.E. Dillon Published: February, 2022 Abstract Bumble bees thrive in cold climates including high latitude and high altitude regions around the world, yet cold tolerance strategies are largely unknown for most species. To determine bumble bee cold tolerance strategy, we exposed bumble bees to a range of low…