Diet study of the lizard Agama picticauda on Réunion Island
Invasive species can have devastating effects when introduced into remote island ecosystems, and a fundamental aspect of this concerns the diet of these exotic taxa. Here, we employed a DNA metabarcoding approach to determine the diet of the lizard Agama picticauda on Réunion Island, where it was introduced in 1995. Two separate markers were used to identify dietary components: COI for animals and trnL for plants. The arthropod aspect was notably conservative, with the agama continuing to predominantly consume ants, as they do in their native range. A variety of other invertebrates were also preyed upon, the vast majority being introduced species. For plants, again a wide variety was detected, and while most could not be identified fully, it seems that agamas are deliberately consuming many species, rather than accidentally ingesting them along with targeted invertebrates. Agamas may play a role in seed dispersal of invasive plant species. We also detected some nematode groups, although with limited comparative sequences, these could not be identified to the species level. Several invertebrate records appear to be new for Réunion Island, highlighting how reptiles can be considered as excellent biodiversity samplers, with barcoding diet studies providing novel data on poorly known invertebrate groups. The minimal identification of endemic prey items may reflect the fact that agamas are still predominantly occupying anthropogenically disturbed parts of the island. Our study therefore provides baseline data that can be used to determine the impact of this introduced lizard as it spreads through the ecosystem.
Invasive species can have devastating effects when introduced into remote island ecosystems, and a fundamental aspect of this concerns the diet of these exotic taxa. Here, we employed a DNA metabarcoding approach to determine the diet of the lizard Agama picticauda on Réunion Island, where it was introduced in 1995. Two separate markers were used to identify dietary components: COI for animals and trnL for plants. The arthropod aspect was notably conservative, with the agama continuing to predominantly consume ants, as they do in their native range. A variety of other invertebrates were also preyed upon, the vast majority being introduced species. For plants, again a wide variety was detected, and while most could not be identified fully, it seems that agamas are deliberately consuming many species, rather than accidentally ingesting them along with targeted invertebrates. Agamas may play a role in seed dispersal of invasive plant species. We also detected some nematode groups, although with limited comparative sequences, these could not be identified to the species level. Several invertebrate records appear to be new for Réunion Island, highlighting how reptiles can be considered as excellent biodiversity samplers, with barcoding diet studies providing novel data on poorly known invertebrate groups. The minimal identification of endemic prey items may reflect the fact that agamas are still predominantly occupying anthropogenically disturbed parts of the island. Our study therefore provides baseline data that can be used to determine the impact of this introduced lizard as it spreads through the ecosystem.
catarina rato