The Eye of the Beholder: Male Mate Choice Is Influenced by Partner Infection Status and Self-Condition

Research on mate choice has predominantly emphasized the female perspective, often neglecting the male viewpoint. In studies where infection status is considered a factor in mate choice, two critical questions emerge: (a) how does the condition of the choosing individual influence mate preferences? and (b) do the choosier sex prioritize healthy partners because of their attractiveness, or to mitigate infection risk? Here we investigated these questions in Tenebrio molitor male mate preferences concerning male condition and female infection status. We found that males preferred healthy females over infected ones, which corresponded with an increased likelihood of egg-laying by healthy females. Importantly, survival rates did not differ between males mating with infected versus healthy females. Notably, when males were food-deprived, they showed no preference between infected and control females. This lack of preference was not attributable to infection avoidance, as males did not distinguish between (a) infected and healthy males, or (b) infected and sterilized food sources. These results support the condition-dependent preference hypothesis, suggesting that male mate choice is primarily influenced by their own condition rather than by parasite avoidance.