Abstract
Alternative Reproductive Tactics (ARTs) are a phenomenon observed in nature
where males of the same species adopt different strategies to attract females. They
may either engage in energy-intensive behaviors such as nest guarding, providing
parental care, honest signaling, or monopolizing territories, or they may bypass
these costly expenditures and directly look for receptive females. Males that invest
in these energy-exhaustive processes are referred to as "territorials," while those
who avoid such costs are known as "roamers". This division of tactics can lead to
intrasexual competition and variability in mate availability. However, this competition
is costly for both territorial and roamer males. A potential way to mitigate these costs
could be by investing in cryptic traits, such as cognitive abilities and secondary
sexual characteristics. In my study, I sought to understand whether different
reproductive tactics impact cognitive abilities—specifically spatial learning and
problem-solving behavior—as well as secondary sexual characteristics like sperm
quality, quantity, and testosterone concentration in male house mice (Mus musculus
domesticus) (N = 34, Territorial = 12, Roamer = 22). My findings show that
territorials were quicker to learn how to navigate the maze, used to assess spatial
learning, and displayed more curiosity in problem-solving tasks. However, roamers
demonstrated greater persistence and slightly better problem-solving performance.
Despite these cognitive differences, I found no significant differences in secondary
sexual characteristics between the two tactics. These results align with theories
predicting that territorials should possess superior spatial learning ability for mate-
guarding or excluding intruders while lower-ranking roamers should excel in
problem-solving due to their otherwise limited access to resources. Overall, my
study reveals that wild mice are highly cautious in allocating energy to costly traits
like cognition, only doing so when it aligns with their ecological needs. Although cognitive abilities remain complex to interpret, my findings suggest that examining
their ecological relevance may offer valuable insights into within-species differences.
