Frugivory by Three Species of Lizards in Madagascar: Implication for Their Ecological Roles as Seed Dispersers

Abstract

Animal-mediated seed dispersal, particularly endozoochory, is an important ecological process for numerous plant species. Although most research on endozoochory has focused on birds and mammals, some lizards are also known to consume fruits and play a significant role in seed dispersal. However, lizards remain overlooked as frugivores and seed dispersers. To clarify the role of lizards as seed dispersers in forest ecosystems, we conducted behavioral observations and fecal analyses on three diurnal lizard species: Furcifer oustaleti, Oplurus cuvieri, and Zonosaurus laticaudatus in a tropical dry forest in Ankarafantsika National Park, northwestern Madagascar during the wet seasons from 2022 to 2024 (2 years). We also conducted germination trials on seeds defecated by F. oustaleti and O. cuvieri. We captured 89, 254, and 38 individuals of the three lizard species, and 24.7 %, 20.1 %, and 15.8 % of the individuals had seeds in their feces, respectively. Behavioral observations and fecal analyses revealed that F. oustaleti, O. cuvieri, and Z. laticaudatus consumed fruits from 8, 18, and 8 plant species, respectively. For individuals with seeds in their feces, the mean number of defecated seeds per individual was 27.2 (range: 1–300), and we confirmed that some of these species had substantial germination rates (> 50%). Moreover, lizards tended to consume different plant species compared to the Common Brown Lemur (Eulemur fulvus), a principal seed disperser in this forest. These lizards may therefore play important roles as seed dispersers, and their contribution to forest regeneration in Madagascar should be considered.