Feeding behaviour of a large lizard drives the outcome of palm seeds dispersal, with comments on its ecosystem services

Abstract

Frugivory and seed dispersal is recorded for 470 lizard species in 27 families worldwide, including the Neotropical Teiidae with 16 genera and 35 species. Among teiids, the black and white tegu Salvator merianae stands out as the largest fruit-eating species. Herein we describe and illustrate the feeding behaviour of this lizard on fruits of the queen palm Syagrus romanzoffiana at an urban reserve in southeast Brazil in November 2013. The lizard picks up the fruits under the palm and remains there while feeding. Part of the fruits is swallowed whole after little chewing, whereas part is thoroughly chewed, the pulp swallowed and the hard seed discarded. Thus, the seeds discarded under the mother plant are not dispersed and probably have little chance to germinate, whereas those swallowed are eliminated with faeces and dispersed away from the mother plant have better chances to germinate. This dual behaviour seems a novelty among palm fruit-eating lizards and is unrecorded for Teiidae. We also report on some animal food types gathered or hunted by the tegu and comment on the ecological roles and regulating ecosystem services this large lizard delivers at the study site, including plant dispersal, carrion removal, and pest control. Additionally, the tegu digs burrows to brumate in the cold and dry season, acting as ecosystem engineer.