Who ate my chocolate? Small mammals and fruit damage in cacao agroforestry

Small mammals interfere in plant dynamics through seed and seedling predation, and seed dispersion. In anthropogenic systems, some species provide ecosystem services while others are considered pests. Small mammals inhabit cacao agroforestry and may damage cacao fruits. However, knowledge on the harmful species and annual yield loss are scarce. We aimed to estimate the cacao damage produced by small mammals, and search for evidence on the harmful species using two different approaches: associations between the estimated damage and species abundances, and the molecular identification of cacao DNA in small mammal feces. We estimated cacao damage by monthly count of intact and damaged pods. We sampled small mammals using live traps, and analyzed fecal samples from 44 individuals. Estimated damage on mature fruits along the harvest season ranged from 3 to 13% per site. Rhipidomys mastacalis , Hylaeamys seuanezi and Marmosa murina were the most common species. We found a positive association between fruit damage and R. mastacalis abundance. However, cacao DNA was identified in feces of R. mastacalis and M. murina . Both species are arboreal, but only R. mastacalis is adapted to gnaw the cacao peel. Altogether, our results indicate that this rodent is the main responsible for the observed damages, while M. murina may feed opportunistically on fruits previously opened. Reasonable yield loss can be observed in some farms. Studies on resources used by R. mastacalis and negative interactions able to enforce population control should be fostered to inform environmental management with minimal impact to overall small mammal assemblage.