Emanuel Teixeira da Silva

Predation of Native Anurans by Invasive Bullfrogs in Southeastern Brazil: Spatial Variation and Effect of Microhabitat use by Prey

ABSTRACT. Invasive predators are one of the causes of population declines of anurans around the world. The American Bullfrog (Lithobates catesbeianus) stands out among these predators. Based on field observations and stomach content analysis, predation on native anurans by invasive Bullfrogs was investigated in two localities of Southeastern Brazil. The spatial variation in predation and similarity in microhabitat use by native species and Bullfrogs were also determined. Anurans of the families Bufonidae, Hylidae, Leiuperidae and Microhylidae were found among Bullfrog prey. The species preyed upon had medium to high similarity with Bullfrogs regarding microhabitat use. Anurans had high relative importance in the diet of adult Bullfrogs from the site where natural vegetation is preserved. Thus, the possible negative impact of predation by Bullfrogs can be more significant on anuran species which use microhabitats similar to those used by the invasive frogs. This impact may also be higher in preserved sites, increasing the necessity of monitoring and controlling the spread of this invasive species to natural areas. However, as factors other than predation are known to contribute toward negative impacts, further studies are required to clarify the status of invasive Bullfrogs in Brazil.

Diet of the Invasive Frog Lithobates catesbeianus (Shaw, 1802) (Anura: Ranidae) in Viçosa, Minas Gerais State, Brazil

ABSTRACT. Based on the stomach content analysis of 113 individuals, the diet of the invasive amphibian Lithobates catesbeianus (American Bullfrog) was examined in four sites located within the municipality of Viçosa (20°45′S and 42°51′W), state of Minas Gerais, Brazil, from August 2005 to March 2007. The effects of frog size and sexual maturity on stomach contents were determined. Prey items were grouped according to their primary habitat, being classified as aquatic, terrestrial and amphibious. In general, the most frequent prey categories were post-metamorphic Anura, Diplopoda, Hemiptera, Hymenoptera Formicidae and Araneae. The diet of adults of both sexes was similar, but differed from the diet of young frogs. Terrestrial prey were most abundant both in number and occurrence. For adult Bullfrogs, amphibious prey were most significant in volume. There was a significant correlation between prey and predator sizes, as well as a greater consumption of native anurans by larger Bullfrogs. The results confirmed that Bullfrogs have a generalist feeding habit that can have important negative effects on native amphibian communities in environments occupied by this invasive species.

Advertisement Call and Tadpole of Chiasmocleis mantiqueira Cruz, Feio and Cassini, 2007 (Anura, Microhylidae)

Abstract Chiasmocleis mantiqueira is a small microhylid frog recently described from an Atlantic rain forest fragment found in the state of Minas Gerais, southeastern Brazil, whose biology is poorly know. Here, the tadpole and the vocalizations of this species are described from the type locality, along with some information about its natural history. Characteristics of larval external morphology of C. mantiqueira are similar to other described tadpoles of the genus: oral disc without keratinized mouthparts, spiracle single, posterior ventral, and medial vent tube. The body is depressed, rectangular in dorsal view and oval in lateral view, and the tail has a flagellum. The species exhibits an explosive breeding behavior, like other Neotropical microhylids. However, unlike other species in this genus, males of C. mantiqueira do not have a vocal sac, and its call is composed of a single harmonic, not a pulsed, note. Thus, the characteristics of the call of C. mantiqueira contradict the hypothesis that call structure can support the monophyly of Chiasmocleis, and further data are required to clarify the relationship of the species in this genus.

Amphibia, Anura, Hylodidae, Megaelosia apuana Pombal, Prado and Canedo, 2003: distribution extension, new state record and geographic distribution map

In this study we report the first record of the giant torrent frog Megaelosia apuana in the state of Minas Gerais, southeastern Brazil. The finding of this species at Reserva Particular do Patrimonio Natural (RPPN) Mata do Sossego, municipality of Simonesia, east of Minas Gerais extends its geographic distribution by 120 km from the type locality, and 45 km northwest from its westernmost known record. A geographic distribution map is presented.

Amphibia, Anura, Leiuperidae, Physalaemus feioi Cassini, Cruz and Caramaschi, 2010: distribution extension

We provide new records of the recently described frog Physalaemus feioi in the state of Minas Gerais, southeastern Brazil. Records presented here extend the distribution of P. feioi around 113 km straight north from Parque Estadual da Serra do Brigadeiro, the previously northernmost known record for the species.

Amphibia, Anura, Pipidae, Pipa carvalhoi (Miranda-Ribeiro, 1937): distribution extension and geographic distribution map in the southeast of Brazil

We report new records for the Carvalho’s Surinam Toad Pipa carvalhoi in state of Minas Gerais, southeast of Brazil, extending its occurrence in the southern portion of its known geographic range.

Amphibia, Anura, Hylidae, Sphaenorhynchus botocudo Caramaschi, Almeida and Gasparini, 2009: first state record and first record out of the type locality

This study presents the first record of the recently-described Lime Treefrog Sphaenorhynchus botocudo Caramaschi, Almeida, and Gasparini, 2009 in the state of Bahia, and the first record out of its type locality.

Food Habits of Invasive Bullfrogs and Native Thin-Toed Frogs Occurring in Sympatry in Southeastern Brazil

Abstract. Although the feeding ecology of sympatric anurans has been studied, less is known about the food habits of co-occurring invasive and native frog species, particularly in the Neotropics. We compared the food habits of invasive bullfrogs (Lithobates catesbeianus) and native thin-toed frogs (Leptodactylus cf. latrans) in a locality of Southeastern Brazil. Monthly field surveys and stomach content analyses were performed between September 2008–April 2009 and September–November 2009. Prey items were identified to the lowest taxonomic level and diet overlap was estimated. Juveniles of both species had similar body sizes, but adult thin-toed frogs were smaller than adult bullfrogs. Insects and spiders dominated the diets of juveniles of both species and of adult thin-toed frogs, whereas anurans and water bugs predominated in adult bullfrog diets. Thin-toed frogs consumed a larger number of prey items than bullfrogs, which in turn consumed more voluminous prey items. Aquatic and amphibious prey items were more common in bullfrog diets. Adult thin-toed frogs preyed on juvenile bullfrogs, although the opposite was not observed. Diet overlap of equivalent age groups varied from low to intermediate between species. Our results showed that that dietary differences may be one of the factors allowing the coexistence of both species at the studied area, although not excluding possible negative impacts on native thin-toed frogs because of the presence of invasive bullfrogs.

New records of Ischnocnema verrucosa Reinhart and Lütken, 1862 and I. surda Canedo, Pimenta, Leite and Caramaschi, 2010 (Anura, Brachycephalidae) in Minas Gerais state, Brazil

Herein we provide new records of the leaf litter frogs Ischnocnema verrucosa and I. surda for the state of Minas Gerais, Southeast of Brazil. Our records fill the current gap in the geographic distribution of I. verrucosa in the east of Minas Gerais, and extend the distribution of I. surda in about 117 km straight southeast of its type locality. We also provide discussions regarding diagnose characters of I. surda .

Amphibia, Anura, Hylodes babax Heyer, 1982 (Hylodidae), Dendropsophus ruschii (Weygoldt and Peixoto, 1987) and Bokermannohyla ibitipoca (Caramaschi and Feio, 1990) (Hylidae): Distribution extension and geographic distribution map

We report new records for the poorly known species Hylodes babax (fourth record), Dendropsophus ruschii (fourth record) and Bokermannohyla ibitipoca (fifth record), from an Atlantic Forest fragment in the eastern region of the Mantiqueira mountain range in Minas Gerais, Brazil.