Senescence and early-life performance as predictors of lifespan in a solitary bee

Authors: SZEJNER-SIGAL, ANDRE - North Dakota State University; Rinehart, Joseph; BOWSHER, JULIA - North Dakota State University; GREENLEE, KENDRA - North Dakota State University

Submitted to: Proceedings of the Royal Society. B. Biological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2025
Publication Date: 4/16/2025
Citation: Szejner-Sigal, A., Rinehart, J.P., Bowsher, J.H., Greenlee, K.J. 2025. Senescence and early-life performance as predictors of lifespan in a solitary bee. Proceedings of the Royal Society. B. Biological Sciences. https://doi.org/10.1098/rspb.2024.2637.
DOI: https://doi.org/10.1098/rspb.2024.2637

Interpretive Summary: When an organism ages, performance begins to decline. But not all individuals of the same age decline at the same time. To understand aging better, we need to explore why some individuals age faster than others. In this study we measured how different traits decline with age in the important pollinator, Megachile rotundata. We also examined whether early life performance could predict how long they will live. By tracking individual bees throughout their lives, we measured metabolism, cold tolerance, mass, and walking activity levels. Our results show that only cold tolerance and walking activity decline with age, revealing that not all traits decline with age in this bee species. We also found that young bees that have high mass and better at cold tolerance tend to live longer. Interestingly, these results only apply to female bees. These results highlight how aging is a complex process, and understanding it can help us predict the health and lifespans of pollinators.

Technical Abstract: Performance tends to decline with age, including muscle function and stress tolerance. Yet, performance can vary widely among individuals within the same age group, showing that chronological age does not always represent biological age. To better understand ageing, we need to examine what drives some individuals to age faster than others. In order to achieve this, first we need to be able to predict whether an individual will have a long or short lifespan. In this study, we conducted a longitudinal study tracking individual-level locomotor activity, chill-coma recovery time, and metabolic rates, and assessed whether early-life performance is linked to lifespan using the solitary bee Megachile rotundata. We found that locomotor activity and chill-coma recovery times decline in old adults. However, resting metabolic rate did not change with age. We also found low cold tolerance and low mass at emergence in early-life are linked to shorter female lifespans, showing that early-life performance can explain some of the variation in lifespan in a population. Finally, these results also show that not all traits decline with age within the same species, and shed new light on sexual dimorphism in physiological traits and ageing.