Leptodactylus chaquensis Cei 1950 is a large frog in the Leptodactylus ocellatus group (Frost, 2011). The distribution range of this species includes Argentina, Bolivia, Brazil, Paraguay and Uruguay (Calderon et al., 2009). Individuals are terrestrial, mainly nocturnal, and males call from the edges of permanent or temporary water bodies (Uetanabaro et al., 2008). Information about their predation is scarce. Prado (2003) reported predation of this species by Tigrisoma lineatum and Clelia bicolor (juvenile) in southern Pantanal.

The whistling heron, Syrigma sibilatrix (Temminck, 1824), is a medium-size heron in the family Ardeidae, with a preference for the consumption of arthropods, especially insects such as grasshoppers (Sick, 1997), as well as fishes, amphibians, small reptiles and plants (del Hoyo et al., 1992; Reinert et al., 2004). Individuals forage alone or in pairs, preferably in open areas or in dry or wet ponds and deeper lakes with floating vegetation (Kushlan et al., 1982). The species is distributed from Venezuela to Uruguay, northern Argentina and Brazil (Blamires et al., 2005).

During a herpetofaunal survey conducted on 24May 2011, in the municipality of Nova Andradina, Mato Grosso do Sul state, southwestern Brazil (-21.995967ºS, -53.423092ºW, Datum SAD-69), at 09:13 h, we observed a S. sibilatrix capturing an adult of L. chaquensis (Fig. 1). Predation occurred at the margins of a semi-temporary pond, in a pasture. For approximately ten minutes the bird pecked and pressed the frog at the bottom of the pond, which was apparently dead at the end of that

time. Afterwards, the bird took flight with the frog in its beak.

In general, amphibians are abundant, have a small to moderate body size, and exhibit gregarious behavior during the breeding season. This makes them potential preys of all classes of vertebrates, invertebrates and carnivorous plants, so that they play an important role in trophic chains (Duellman and Trueb, 1994). Predation is one of the principal causes of mortality in natural populations of anurans and can occur in any life history stage (Zug et al., 2001; Wells, 2007). Toledo (et al., 2007) divided the predation events of anurans by birds into two categories: 1) Opportunistic, those who feed on anurans occasionally and opportunistically, these predators are diet generalists and prey on anurans when they occasionally encounter them in nature; 2) Convenience, when they are not predators specialized on anurans, but feed on them with regularity. In this case, the most representative predators are those who exhibit similar habits to the anurans, facilitating their (predator-prey) encounters. We consider that the predation of L. chaquensis can be classified as convenience.

Acknowledgements. We are grateful to Dr Cynthia P. A. Prado for confirmation of L. chaquensis identification and suggestions in the text

References

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Herpetology Notes, volume 6: 261-262 (2013) (published online on 14 June 2013)

Predation on Leptodactylus chaquensis (Anura: Leptodactylidae) by the whistling heron Syrigma sibilatrix (Ciconiiformes:

Ardeidae) in Central Brazil

Camila Aoki1,* and Paulo Landgref Filho2

1 Universidade Federal de Mato Grosso do Sul, Campus Universitário de Aquidauana – CPAQ. CEP 79200-000 - Aquidauana, MS, Brasil

2 Universidade Federal de Mato Grosso do Sul, CCBS – Laboratório de Zoologia. CEP 79070-900 - Campo Grande, MS, Brasil

*Corresponding author; e-mail: aokicamila@yahoo.com.br

Camila Aoki & Paulo Landgref Filho262

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Figure 1. An adult Leptodactylus chaquensis being preyed by an individual of Syrigma sibilatrix in the municipality of Nova Andradina, Mato Grosso do Sul state, southwestern Brazil.

Accepted by Philip de Pous