Consequences of nescient mating: Artificial insemination increases cub rejection in the giant panda (Ailuropoda melanoleuca)

Artificial insemination (AI) is a valuable tool for conservation breeding programs as it can promote reproductive success and genetic diversity in species with decreasing populations. However, females that undergo AI do not experience natural mating events, which we term, "nescient mating. " Thus, these females would not be able to assess the quality of their mate through physical, olfactory, or visual cues. Previous research has found that AI can lead to diminished breeding outcomes when compared to natural mating. In this study, we investigated whether fertilization method (natural mating versus AI) affects postpartum behaviors, such as cub rejection and maternal care in female giant pandas. We analyzed data from 202 cubs and 43 mother-cub dyads between 1996 and 2018. We did not find a difference in gestation length, cub weight, or cub survivorship between naturally mated and artificially inseminated females. Compared to naturally inseminated females, artificially mated females were significantly more likely to reject cubs (p = 0.039). Contrary to what we had predicted, maternal care and infant behaviors during the first month did not differ between natural mating and AI groups. Taken together, our results indicate that female giant pandas who experienced nescient mating may have reduced offspring investment, manifest in increased cub rejection. However, the lack of behavioral differences between AI and natural mating groups was encouraging, indicating that once a female accepted a cub to rear, maternal care was adequate to ensure cub survival. Nonetheless, we recommend that conservation breeding programs prioritize natural mating as higher rates of maternal rejection increase the facility and human time cost of cub rearing and also the chances of detrimental downstream effects on offspring adult behaviors in the giant panda.