# Male Mating Preference for Larger Females Does Not Vary Among Age Classes in the Long‐Lived Beetle Bolitotherus cornutus

## TL;DR

Older male beetles do not show less preference for larger females than younger males, challenging assumptions about aging and mating behavior.

## Contribution

This study is the first to show that male mating preferences for large females do not decline with age in a long-lived insect.

## Key findings

- Males of B. cornutus consistently prefer large females regardless of age.
- No significant difference in preference strength was found between young and old males in both lab and field settings.
- Age may not be a strong driver of male mate preference variation in long-lived species.

## Abstract

Theory and past experimental work suggest that as males age, the strength of their mate preference should decrease. However, the empirical work investigating this question has primarily been conducted in insects that have very short life spans and often live for just a single mating season. This leaves a gap in our understanding of the relationship between male mate preference and age across taxa, as age can conflate with other ecological changes in a single mating season. In this study, we ask how the strength of preference for large female body size changes as males age in a long‐lived insect, Bolitotherus cornutus. We used a two‐pronged approach of both laboratory behavior trials and cross‐sectional analyses of observations in a wild metapopulation to answer this question. We found that males overall exhibited a preference for large females, but there was no significant difference between the preference strength of young and old males in either the laboratory experiment or field observations. Our work suggests that age may not play as important a role in variation in male mate preference as predicted by previous findings, especially in long‐lived animals. Instead, processes such as senescence, breeding season termination, or mate availability may be stronger drivers of male mate preference variation.

An increasing amount of research has found that males can also be selective for female traits. Surprisingly, old males in the long‐lived beetle
B. cornutus
were not significantly less choosy than young males. This calls attention to our assumptions about aging and the trends in behavior it may drive.