Conquering Brazil: the invasion by the exotic gekkonid lizard Hemidactylus mabouia (Squamata) in Brazilian natural environments

In this study we review the records regarding occurrence of Hemidactylus mabouia Moreau De Jonnès, 1818 in Brazil, looking for records of the species in natural habitats, in order to assess the present status of this gecko as an exotic or invasive alien species in the country. We surveyed the available records of H. mabouia living in natural conditions, considering secondary data obtained from the literature, supplemented with original field records obtained by the authors during fieldwork. We found a total of 36 records in the literature and/or field records reporting the occurrence of H. mabouia in natural habitats in 36 different localities in 13 Brazilian states. The states presenting a higher number of records were Rio de Janeiro (seven), Bahia, São Paulo (six), and Espírito Santo (five different areas). We show that the invasion of Brazilian natural habitats by H. mabouia has taken place for some decades. Presently we have consistent records that it has invaded natural habitats in 13 Brazilian states. This suggests thatit is important to start monitoring H. mabouia in order to measure the rate and effectiveness of its establishment in natural habitats in Brazil and also to evaluate the potential negative effects of this invasion on sympatric species.

Diet of the lizard Ecpleopus gaudichaudii (Gymnophthalmidae) in Atlantic Rainforest, state of Rio de Janeiro, Brazil

In this study we analyzed the diet of the gymnophthalmid lizard Ecpleopus gaudichaudii Duméril & Bibron, 1839, a typical inhabitant of the forest-floor leaf litter, in an Atlantic Forest area in the state of Rio de Janeiro, southeastern Brazil. The 26 individuals sampled during the study had a mean snout-vent length (SVL) of 36.2 ± 4.2 mm and a mean jaw width (JW) of 4.1 ± 0.5 mm. We did not find differences in SVL between males and females, though the sexes differed in JW when the effect of body size was factored out, with females presenting higher values. The diet of the lizards was composed exclusively of arthropods, especially isopods and orthopterans. The similarity in trophic niches among seasons (volumetric and numerical proportions of prey categories consumed) were 0.096 and to 0.43, respectively. There were also no detectable seasonal differences in mean number and mean volume of prey ingested, as well as no significant influence of lizard SVL on prey number and of lizard JW on mean prey volume, which may reflect the tendency of E. gaudichaudii to feed on few, relatively large prey.

Conquering Brazil: the invasion by the exotic gekkonid lizard Hemidactylus mabouia (Squamata) in Brazilian natural environments

In this study we review the records regarding occurrence of Hemidactylus mabouia Moreau De Jonnès, 1818 in Brazil, looking for records of the species in natural habitats, in order to assess the present status of this gecko as an exotic or invasive alien species in the country. We surveyed the available records of H. mabouia living in natural conditions, considering secondary data obtained from the literature, supplemented with original field records obtained by the authors during fieldwork. We found a total of 36 records in the literature and/or field records reporting the occurrence of H. mabouia in natural habitats in 36 different localities in 13 Brazilian states. The states presenting a higher number of records were Rio de Janeiro (seven), Bahia, São Paulo (six), and Espírito Santo (five different areas). We show that the invasion of Brazilian natural habitats by H. mabouia has taken place for some decades. Presently we have consistent records that it has invaded natural habitats in 13 Brazilian states. This suggests thatit is important to start monitoring H. mabouia in order to measure the rate and effectiveness of its establishment in natural habitats in Brazil and also to evaluate the potential negative effects of this invasion on sympatric species.

Diet of the lizard Ecpleopus gaudichaudii (Gymnophthalmidae) in Atlantic Rainforest, state of Rio de Janeiro, Brazil

In this study we analyzed the diet of the gymnophthalmid lizard Ecpleopus gaudichaudii Duméril & Bibron, 1839, a typical inhabitant of the forest-floor leaf litter, in an Atlantic Forest area in the state of Rio de Janeiro, southeastern Brazil. The 26 individuals sampled during the study had a mean snout-vent length (SVL) of 36.2 ± 4.2 mm and a mean jaw width (JW) of 4.1 ± 0.5 mm. We did not find differences in SVL between males and females, though the sexes differed in JW when the effect of body size was factored out, with females presenting higher values. The diet of the lizards was composed exclusively of arthropods, especially isopods and orthopterans. The similarity in trophic niches among seasons (volumetric and numerical proportions of prey categories consumed) were 0.096 and to 0.43, respectively. There were also no detectable seasonal differences in mean number and mean volume of prey ingested, as well as no significant influence of lizard SVL on prey number and of lizard JW on mean prey volume, which may reflect the tendency of E. gaudichaudii to feed on few, relatively large prey.

Diet of the lizard Ecpleopus gaudichaudii (Gymnophthalmidae) in Atlantic Rainforest, state of Rio de Janeiro, Brazil

In this study we analyzed the diet of the gymnophthalmid lizard Ecpleopus gaudichaudii Duméril & Bibron, 1839, a typical inhabitant of the forest-floor leaf litter, in an Atlantic Forest area in the state of Rio de Janeiro, southeastern Brazil. The 26 individuals sampled during the study had a mean snout-vent length (SVL) of 36.2 ± 4.2 mm and a mean jaw width (JW) of 4.1 ± 0.5 mm. We did not find differences in SVL between males and females, though the sexes differed in JW when the effect of body size was factored out, with females presenting higher values. The diet of the lizards was composed exclusively of arthropods, especially isopods and orthopterans. The similarity in trophic niches among seasons (volumetric and numerical proportions of prey categories consumed) were 0.096 and to 0.43, respectively. There were also no detectable seasonal differences in mean number and mean volume of prey ingested, as well as no significant influence of lizard SVL on prey number and of lizard JW on mean prey volume, which may reflect the tendency of E. gaudichaudii to feed on few, relatively large prey.

Conquering Brazil: the invasion by the exotic gekkonid lizard Hemidactylus mabouia (Squamata) in Brazilian natural environments

In this study we review the records regarding occurrence of Hemidactylus mabouia Moreau De Jonnès, 1818 in Brazil, looking for records of the species in natural habitats, in order to assess the present status of this gecko as an exotic or invasive alien species in the country. We surveyed the available records of H. mabouia living in natural conditions, considering secondary data obtained from the literature, supplemented with original field records obtained by the authors during fieldwork. We found a total of 36 records in the literature and/or field records reporting the occurrence of H. mabouia in natural habitats in 36 different localities in 13 Brazilian states. The states presenting a higher number of records were Rio de Janeiro (seven), Bahia, São Paulo (six), and Espírito Santo (five different areas). We show that the invasion of Brazilian natural habitats by H. mabouia has taken place for some decades. Presently we have consistent records that it has invaded natural habitats in 13 Brazilian states. This suggests thatit is important to start monitoring H. mabouia in order to measure the rate and effectiveness of its establishment in natural habitats in Brazil and also to evaluate the potential negative effects of this invasion on sympatric species.

Ecology of Ischnocnema parva (Anura: Brachycephalidae) at the Atlantic Rainforest of Serra da Concórdia, state of Rio de Janeiro, Brazil

Ischnocnema (Brachycephalidae) includes many species that are important members of the leaf litter frog communities in the Atlantic Rainforest of Brazil. Ischnocnema parva (Girard, 1853) is endemic to the Atlantic Rainforest biome and is restricted to the forests of southeastern Brazil. Currently, the available information about the ecology of I. parva is scarce. We studied the diet, the habitat use, reproduction and density of I. parva in an area of Atlantic Rainforest at the Concórdia mountain range, Rio de Janeiro. Individuals of I. parva were captured in April 2005 using different sampling methods: time constrained search (transects), plots of 5 x 5 m (25 m²) on the litter, and pitfall traps with drift fences. We found 240 frogs; 35 females and 205 males. Females (mean SVL = 19.1 mm) were significantly larger (F1,238 = 143.016, R² = 0.375, p 0.001) than males (13.2 mm). The species preyed mainly on arthropods, with ants and isopods being the most important items, both showing high values of importance index (Ix = 50.0 and 26.7, respectively). Ischnocnema parva is a terrestrial species whose preferential microhabitat at the Serra da Concórdia was the litter of the forest floor (78.7%). The activity was predominantly crepuscular-nocturnal and the estimated density of I. parva was 24.9 ind/100 m². For the eight ovigerous females captured, the mean number of mature oocytes per female was 25 (range: 22-30) and the oocyte mean diameter was 1.11 mm (N = 40 oocytes). Oocyte number increased with female body size (R² = 0.504, F1,6 = 6.107, p 0.05, N = 8), indicating that as females increase in size they produce larger clutches. Some ecological aspects such as diet and microhabitat use were similar to that observed for an insular population of I. parva, whereas reproductive traits differed. Thus, long term studies are necessary to understand the extent to which these differences are explained by environmental factors.

Influence of structural habitat use on the thermal ecology of Gonatodes humeralis (Squamata: Gekkonidae) from a transitional forest in Maranhão, Brazil

We studied the structural habitat use and the thermal ecology of Gonatodes humeralis (Guichenot, 1855) in São Luís, Maranhão, Brazil, to examine intersexual differences in the use of perch features and to simultaneously analyze reciprocal differences on thermal ecology between the sexes. Gonatodes humeralis body temperature was strongly correlated with environmental temperatures (air and substrate), but air temperature had an additional effect on the males' body temperatures after removing the effect of the substrate temperature. Males and females differed significantly in perch height use above ground (males perched higher) but the sexes did not differ in the trunk perimeter used. Gonatodes humeralis tended to use the larger tree trunks available in its environment and selected trunks with deeper leaf litter at the base. It is hypothesized that choosing tree trunks with deeper leaf litter is a defensive behavior against predation.

Ecology of Ischnocnema parva (Anura: Brachycephalidae) at the Atlantic Rainforest of Serra da Concórdia, state of Rio de Janeiro, Brazil

Ischnocnema (Brachycephalidae) includes many species that are important members of the leaf litter frog communities in the Atlantic Rainforest of Brazil. Ischnocnema parva (Girard, 1853) is endemic to the Atlantic Rainforest biome and is restricted to the forests of southeastern Brazil. Currently, the available information about the ecology of I. parva is scarce. We studied the diet, the habitat use, reproduction and density of I. parva in an area of Atlantic Rainforest at the Concórdia mountain range, Rio de Janeiro. Individuals of I. parva were captured in April 2005 using different sampling methods: time constrained search (transects), plots of 5 x 5 m (25 m²) on the litter, and pitfall traps with drift fences. We found 240 frogs; 35 females and 205 males. Females (mean SVL = 19.1 mm) were significantly larger (F1,238 = 143.016, R² = 0.375, p 0.001) than males (13.2 mm). The species preyed mainly on arthropods, with ants and isopods being the most important items, both showing high values of importance index (Ix = 50.0 and 26.7, respectively). Ischnocnema parva is a terrestrial species whose preferential microhabitat at the Serra da Concórdia was the litter of the forest floor (78.7%). The activity was predominantly crepuscular-nocturnal and the estimated density of I. parva was 24.9 ind/100 m². For the eight ovigerous females captured, the mean number of mature oocytes per female was 25 (range: 22-30) and the oocyte mean diameter was 1.11 mm (N = 40 oocytes). Oocyte number increased with female body size (R² = 0.504, F1,6 = 6.107, p 0.05, N = 8), indicating that as females increase in size they produce larger clutches. Some ecological aspects such as diet and microhabitat use were similar to that observed for an insular population of I. parva, whereas reproductive traits differed. Thus, long term studies are necessary to understand the extent to which these differences are explained by environmental factors.

Influence of structural habitat use on the thermal ecology of Gonatodes humeralis (Squamata: Gekkonidae) from a transitional forest in Maranhão, Brazil

We studied the structural habitat use and the thermal ecology of Gonatodes humeralis (Guichenot, 1855) in São Luís, Maranhão, Brazil, to examine intersexual differences in the use of perch features and to simultaneously analyze reciprocal differences on thermal ecology between the sexes. Gonatodes humeralis body temperature was strongly correlated with environmental temperatures (air and substrate), but air temperature had an additional effect on the males' body temperatures after removing the effect of the substrate temperature. Males and females differed significantly in perch height use above ground (males perched higher) but the sexes did not differ in the trunk perimeter used. Gonatodes humeralis tended to use the larger tree trunks available in its environment and selected trunks with deeper leaf litter at the base. It is hypothesized that choosing tree trunks with deeper leaf litter is a defensive behavior against predation.

Influence of structural habitat use on the thermal ecology of Gonatodes humeralis (Squamata: Gekkonidae) from a transitional forest in Maranhão, Brazil

We studied the structural habitat use and the thermal ecology of Gonatodes humeralis (Guichenot, 1855) in São Luís, Maranhão, Brazil, to examine intersexual differences in the use of perch features and to simultaneously analyze reciprocal differences on thermal ecology between the sexes. Gonatodes humeralis body temperature was strongly correlated with environmental temperatures (air and substrate), but air temperature had an additional effect on the males' body temperatures after removing the effect of the substrate temperature. Males and females differed significantly in perch height use above ground (males perched higher) but the sexes did not differ in the trunk perimeter used. Gonatodes humeralis tended to use the larger tree trunks available in its environment and selected trunks with deeper leaf litter at the base. It is hypothesized that choosing tree trunks with deeper leaf litter is a defensive behavior against predation.

Ecology of Ischnocnema parva (Anura: Brachycephalidae) at the Atlantic Rainforest of Serra da Concórdia, state of Rio de Janeiro, Brazil

Ischnocnema (Brachycephalidae) includes many species that are important members of the leaf litter frog communities in the Atlantic Rainforest of Brazil. Ischnocnema parva (Girard, 1853) is endemic to the Atlantic Rainforest biome and is restricted to the forests of southeastern Brazil. Currently, the available information about the ecology of I. parva is scarce. We studied the diet, the habitat use, reproduction and density of I. parva in an area of Atlantic Rainforest at the Concórdia mountain range, Rio de Janeiro. Individuals of I. parva were captured in April 2005 using different sampling methods: time constrained search (transects), plots of 5 x 5 m (25 m²) on the litter, and pitfall traps with drift fences. We found 240 frogs; 35 females and 205 males. Females (mean SVL = 19.1 mm) were significantly larger (F1,238 = 143.016, R² = 0.375, p 0.001) than males (13.2 mm). The species preyed mainly on arthropods, with ants and isopods being the most important items, both showing high values of importance index (Ix = 50.0 and 26.7, respectively). Ischnocnema parva is a terrestrial species whose preferential microhabitat at the Serra da Concórdia was the litter of the forest floor (78.7%). The activity was predominantly crepuscular-nocturnal and the estimated density of I. parva was 24.9 ind/100 m². For the eight ovigerous females captured, the mean number of mature oocytes per female was 25 (range: 22-30) and the oocyte mean diameter was 1.11 mm (N = 40 oocytes). Oocyte number increased with female body size (R² = 0.504, F1,6 = 6.107, p 0.05, N = 8), indicating that as females increase in size they produce larger clutches. Some ecological aspects such as diet and microhabitat use were similar to that observed for an insular population of I. parva, whereas reproductive traits differed. Thus, long term studies are necessary to understand the extent to which these differences are explained by environmental factors.

Reproductive ecology of the invader species gekkonid lizard Hemidactylus mabouia in an area of southeastern Brazil

Hemidactylus mabouia Moreau de Jonnés, 1818 is a "fixed" clutch size exotic species well established in Brazil. In this paper we investigate some reproductive strategies adopted to minimize the costs of invariant clutch size to this invader species living in an environment with marked climatic seasonality in Southeastern Brazil (22°56’S; 46°55’W). The study was carried out from April 2002 to March 2003. Females and males attain maturity at 47.9mm and 46.9mm SVL, respectively. Larger females tended to produce larger eggs. The reproduction occurred throughout the year, but only at the wet season the females increase the clutch frequency. There was a significant variation in mean testis volume among the months throughout the year and the largest means were recorded between August and December. Maternal investment on egg size, increase on clutch frequency and seasonal increase on testis volume can represent important reproductive strategies of this invader species living in an non-urban habitat whit climatic seasonality (dry and cold weather season).

Hemidactylus mabouia Moreau de Jonnés, 1818 é uma espécie exótica, com tamanho fixo de ninhada e bem estabelecida no Brasil. Neste estudo foram investigadas algumas estratégias reprodutivas adotadas no sentido de minimizar os custos do tamanho fixo de ninhada nesta população que vive em uma região onde há uma marcada sazonalidade climática. O estudo foi realizado entre abril de 2002 e março de 2003 em Valinhos (22°56’S; 46°55’W; sudeste do Brasil). Os resultados indicaram que as fêmeas atingem a maturidade sexual com 47,9mm enquanto que os machos com 46,9mm. As fêmeas maiores tendem a produzir ovos maiores. A reprodução ocorre ao longo do ano todo, mas somente durante a estação úmida as fêmeas aumentam a freqüência reprodutiva. O tamanho médio dos testículos sofre uma variação ao longo do ano e as maiores médias foram registradas entre os meses de agosto e dezembro. Investimento maternal no tamanho do ovo, aumento na freqüência reprodutiva e aumento sazonal no volume médio dos testículos podem representar uma importante estratégia reprodutiva desta espécie invasora que habita um campo ruderal com sazonalidade climática marcada (estação fria e seca bem definida).

Reproductive ecology of the invader species gekkonid lizard Hemidactylus mabouia in an area of southeastern Brazil

Hemidactylus mabouia Moreau de Jonnés, 1818 is a "fixed" clutch size exotic species well established in Brazil. In this paper we investigate some reproductive strategies adopted to minimize the costs of invariant clutch size to this invader species living in an environment with marked climatic seasonality in Southeastern Brazil (22°56S; 46°55W). The study was carried out from April 2002 to March 2003. Females and males attain maturity at 47.9mm and 46.9mm SVL, respectively. Larger females tended to produce larger eggs. The reproduction occurred throughout the year, but only at the wet season the females increase the clutch frequency. There was a significant variation in mean testis volume among the months throughout the year and the largest means were recorded between August and December. Maternal investment on egg size, increase on clutch frequency and seasonal increase on testis volume can represent important reproductive strategies of this invader species living in an non-urban habitat whit climatic seasonality (dry and cold weather season).

Hemidactylus mabouia Moreau de Jonnés, 1818 é uma espécie exótica, com tamanho fixo de ninhada e bem estabelecida no Brasil. Neste estudo foram investigadas algumas estratégias reprodutivas adotadas no sentido de minimizar os custos do tamanho fixo de ninhada nesta população que vive em uma região onde há uma marcada sazonalidade climática. O estudo foi realizado entre abril de 2002 e março de 2003 em Valinhos (22°56S; 46°55W; sudeste do Brasil). Os resultados indicaram que as fêmeas atingem a maturidade sexual com 47,9mm enquanto que os machos com 46,9mm. As fêmeas maiores tendem a produzir ovos maiores. A reprodução ocorre ao longo do ano todo, mas somente durante a estação úmida as fêmeas aumentam a freqüência reprodutiva. O tamanho médio dos testículos sofre uma variação ao longo do ano e as maiores médias foram registradas entre os meses de agosto e dezembro. Investimento maternal no tamanho do ovo, aumento na freqüência reprodutiva e aumento sazonal no volume médio dos testículos podem representar uma importante estratégia reprodutiva desta espécie invasora que habita um campo ruderal com sazonalidade climática marcada (estação fria e seca bem definida).