Do fruit reflectance properties affect avian frugivory in New Zealand?

Abstract

ABSTRACT Fleshy fruits come in a diversity of colours. Some of this diversity can be attributed to unique selection pressures exerted by different types of frugivores. For example, mammals tend to consume green, yellow, orange and brown fruits, while birds normally consume red and black fruits. However, it is not yet clear whether the diversity of colours displayed within assemblages of bird-dispersed fruits can be attributed to avian colour preferences. We tested whether the reflectance properties of a fleshy fruited plant community from New Zealand predict their removal by birds. All data were collected from 10 common fleshy-fruited plant species during the austral summer (December 2018–April 2019) in a fenced forest reserve on the North Island of New Zealand. We found that fruit removal rates varied amongst plant species and frugivore preferences were not correlated with fruit conspicuousness, brightness, chroma and distinctiveness, suggesting that fruit reflectance properties are unrelated to avian frugivory in our study site. Overall, results from this study suggest that evidence for frugivore-mediated selection of fruit colour diversity may be scale dependent and needs to be investigated at higher taxonomic scales. Future studies examining other factors such as fruit abundance and fruit displays may reveal the finer mechanisms of frugivore-fruit selection