Incorporating free partner choice into conservation breeding: the case for long-distance preference testing

Abstract

Conservation breeding programmes aim to maintain sufficient genetic diversity in ex situ populations of endangered species. However, current breeding recommendations, that aim to retain this genetic diversity at population level, are often unsuccessful, potentially because breeding programmes currently do not take partner preferences of individuals into account. Since transporting animals to assess compatibility is logistically difficult and stressful, this article argues for the development of long-distance partner preference tests that use visual, auditory, and/or olfactory signals. A review of existing literature demonstrates that allowing for partner choice in live settings consistently improves fitness outcomes across taxa. I discuss how partner preferences may be measured in a long-distance setting through partial signal designs, and discuss four critical challenges to these methods: selecting the correct sensory modalities, interpreting ambiguous behavioural responses, accounting for temporal variations in partner preferences, and the lack of validation against actual breeding outcomes. To address these challenges, future studies should adopt a biocentric approach to stimulus selection, ensure that testing happens during periods of heightened sexual motivation (e.g., oestrous), and validate isolated preferences with live interaction data or a breeding phase. Successfully refining these methods could allow zoos to incorporate partner preferences into breeding recommendations, thereby improving their success.