Resource and mate availability, and previous social experience modulate mate choice in the copepods Acartia tonsa and Acartia hudsonica

- Food availability, encounter time, and social experience influence copepod mate choice.
- Male and female mate choices were affected differently by the experimental variables.
- Variable mate choices suggest that copepods use a flexible mate-sampling strategy.

Copepods, the most abundant metazoans in the oceans, exhibit sexual selection through mate choice. Mate choice may depend on resource and mate availability, mate quality, and the ability of an individual to assess potential mates. We measured the relative strength of mate choice for body size in male and female individuals of the copepod species Acartia tonsa and Acartia hudsonica as a function of food availability, encounter time, and previous social experience with the same and opposite sex. Mate choice in A. tonsa females depended on food availability and previous exposure to the opposite sex, whereas exposure to the opposite sex and encounter time affected mate choice in males. For A. hudsonica, previous social experience with the same and opposite sexes and encounter times were important for mate choice in females, and food availability and encounter time affected mate choice in males. The results suggest that mate choice responds to resource and mate availability, as well as social experience, but that the responses are species and sex-specific even within the same genus. Therefore, these copepods appear to have a flexible mate-sampling strategy that allows them to raise or lower their mate preferences in order to balance the benefits and costs associated with finding a desired mate.