Can fruiting plants control animal behaviour and seed dispersal distance?

Abstract

In an Afrotropical forest, we tested the hypothesis that fleshy-fruit plants with interspecific differences in fruit quality and quantity affect ranging behaviour of their seed dispersal vector. If fruiting plants could affect their dispersal vector, the plants also affect their seed dispersal distance and eventually their plant population biology. From 2007 to 2011, we measured seed transport by georeference daily bonobo group movements via GPS. Seed dispersal distance was estimated with mechanistic model, using 1200 georeferenced dispersal events and the average seed transit time through bonobo (24.00 h). We compared dissemination for eight plant species that deal with this trade-off: attracting dispersers by means of fruit quality/quantity versus retaining them in the patch because of the same quality/quantity value that attracted them. Because fruit traits of these eight species were different, we expected a difference in seed dispersal distance. Surprisingly, seed dispersal distances induced by bonobos were not affected by fruit traits. Although fruit nutrient contents, abundance and average patch feeding duration differed between plant species, patch feeding time was not related to subsequent dispersal distances. The apes’ dispersal distance survey gave an average dispersal distance estimated of 1332 ± 24 m from the parent plant (97.9% > 100 m). To conclude, feeding time invested in the patch, fruit quality and abundance had no apparent effect on bonobo seed dispersal distance. The possible effects in plant population biology are discussed.