Diet composition of an invasive population of Lithobates catesbeianus (American Bullfrog) from Argentina

QUIROGA L.; MORENO D.; CATALDO A.; ARAGON, J.; PANTANO, M.; OLIVARES, J.; SANABRIA E.

JOURNAL OF NATURAL HISTORY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2015 vol. 49 p. 1703 - 1716

0022-2933

The Amercian bullfrog Lithobates catesbeianus has been introduced around the world with invasive populations reported from almost all South American countries. A population of this species was introduced in the Calingasta department of San Juan province, which is an arid environment in western Argentina. This work provides information on the dietary composition of an invasive population of L. catesbeianus and compares the degree of dietary overlap between adults and juveniles. Stomach contents of 169 bullfrogs (82 adults and 87 juveniles) were analyzed. Adults from this invasive population consumed 40 prey taxa and juveniles consumed 29 prey taxa. The trophic overlap niche index at the same level shows a value of 0.64 overlap in dietary community between adults and juveniles of this bullfrog. In the adult diet, Hymenoptera (Insecta) was the most numerous prey item (41.8%), followed by Araneae (Arachnida; 13.6%) and Aeglidae (Anomura, Decapoda; 13.4%). Aeglidae was volumetrically the most important trophic item (25.4%) followed by Anura (Amphibia; 25.02%). Among juveniles, Hymenoptera constituted the highest percentage in prey number (77.2%). Aeglidae had the highest IRI value (412.2) and was the most important prey volumetrically (87.5%), followed by fishes. Crabs from the family Aeglidae represented the dominant prey item for both age classes of frogs, and fishes were present in low frequencies. The bullfrog has a generalist diet and high overlap between adults and juveniles.