NOTA

Predation on a tropical house gecko, Hemidactylus mabouia by a juvenile colubrid snake, Chironius bicarinatus, in a Brazilian Atlantic Rainforest area

Davor Vrcibradic¹, Alexia Eisfeld^1,2

¹ Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro - UNIRIO, Avenida Pasteur 458, 22290-240, Rio de Janeiro, Rio de Janeiro, Brasil
² Programa de Pós-Graduação em Ciências Biológicas - Biodiversidade Neotropical - PPGBIO, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro - UNIRIO, Avenida Pasteur 458, 22290-240, Rio de Janeiro, Rio de Janeiro, Brasil

Recibida: 11/12/15
Revisada: 25/08/16
Aceptada: 30/08/16

---

ABSTRACT

Snakes in the Neotropical genus Chironius are mainly batrachophagous, and tend to consume relatively small prey. We present a report of a juvenile Chironius bicarinatus that had ingested a house gecko (Hemidactylus mabouia) corresponding to ca. 62% of its preserved body mass. The ingestion of such a large prey item is unusual for a snake of the genus Chironius, as is the consumption of lizards. Consumption of unusually large prey items may be more common in young snakes than in adults, possibly due to a lower availability of prey of appropriate size and/ or to a lower capacity to evaluate the size of potential prey.

---

 

The colubrid snake genus Chironius Fitzinger, 1826 is endemic to the Neotropical region, occurring from Honduras and Nicaragua southwards to southern Brazil, Uruguay and northeastern Argentina (Dixon et al., 1993; Klaczko et al., 2014), and contains 22 currently recognized species (Hamdan and Fernandes, 2015). Snakes in this genus are diurnal, active foragers that feed almost exclusively on frogs, rarely consuming other types of prey such as salamanders, lizards and birds (Dixon et al., 1993; Marques and Sazima, 2004; Pinto et al., 2008; Bernarde and Abe, 2010; Nascimento et al., 2013). Chironius bicarinatus is distributed exclusively within the Atlantic Rainforest biome in eastern Brazil, extreme northeastern Argentina and northwestern Uruguay, and attains up to ca. 1800 mm in total length (Dixon et al., 1993). The feeding habits of this species have been documented a number of times in the literature, and indicate that it is almost exclusively batracophagous (Dixon et al., 1993; Carvalho-Silva and Fernandes, 1994; Marques and Sazima, 2004; Oliveira, 2008; Hartmann et al., 2009a,b; Bovo and Sueiro, 2012). In the present note, we report on the consumption of a gekkonid lizard by a juvenile C. bicarinatus, emphasizing the relatively large size of the prey compared to the size of the snake.

On March 2015 one of us (DV) received a dead juvenile Chironius bicarinatus (SVL = 300 mm, tail = 156 mm) from an undergraduate student. The snake had been killed by a resident near a forest edge in the region of Alto da Boa Vista (22º 57' 50.5" S, 43º 16' 46.0" W; elevation 380 m a.s.l.), within the urban limits of the city of Rio de Janeiro, state of Rio de Janeiro, Brazil, and later handed over to the student. The reptile had a bulge on its body, suggesting it had eaten a relatively large prey not long before being killed. After dissecting the snake, we found an adult female tropical house gecko, Hemidactylus mabouia (SVL = 56.8 mm, or 18.9% of the snake's SVL) in its stomach. The snake had ingested the lizard head first. The gecko's abdomen was partly digested and the two eggs that were inside it were found loose in the snake's stomach. The combined preserved mass of the gecko (whose tail was broken off near the base and was not inside the snake) and the eggs was 2.8 g, which corresponds to 62.2% of the snake's preserved body mass (i.e. 4.5 g without the prey). The snake and the gecko were deposited at the reptile collection of the Museu Nacional, Rio de Janeiro (MNRJ 25389 and MNRJ 25390, respectively) (Fig. 1).

Figure 1. Juvenile of Chironius bicarinatus (MNRJ 25389) and a house gecko, Hemidactylus mabouia (MNRJ 25390; with its two eggs), removed from the snake stomach.

The ingestion of such a large prey item (compared to the size and body mass of the snake) is unusual for a snake of the genus Chironius, as well as for the family Colubridae (sensu Zaher et al., 2009) as a whole. It has been suggested that the ingestion of relatively small prey items may be a common trait among Neotropical colubrids (Marques et al., 2014). Regarding the genus Chironius in particular, Pinto et al. (2008) reported maximum prey mass/snake mass ratios of 0.21 for C. flavolineatus and 0.19 for C. quadricarinatus, with the mean ratios being only 0.05 and 0.11, respectively (compared to 0.62 in the present report). Nascimento et al. (2013) also remarked that Amazonian C. fuscus feed on relatively small prey (though they did not give prey mass/snake mass ratios). The fact that the snake in the present report was immature may partly explain the relatively large size of the prey it consumed. It has been suggested that the ingestion of unusually large prey items may be more common in young snakes than in adults, presumably due to a lower availability of prey of appropriate size and/or to a lower capacity to evaluate the size of potential prey (Sazima and Martins, 1990). Interestingly, there are reports of juvenile snakes of other species having died as a consequence of swallowing individuals of Hemidactylus mabouia that were comparatively large relative to their size (Nogueira et al., 2013; Gavira et al., 2015).

The present record is unusual not only because of the relative size of the prey, but also because snakes in the genus Chironius are mainly batracophagous, and consume lizards infrequently (Dixon et al., 1993; Nascimento et al., 2013). Since H. mabouia is a nocturnal lizard and Chironius spp. have diurnal habits, the C. bicarinatus probably found and captured the gecko while it was resting in a shelter. Chironius bicarinatus forages actively and is known to pick inactive nocturnal prey from their diurnal retreats (Carvalho-Silva and Fernandes, 1994).

Hemidactylus mabouia has been previously reported as prey of C. bicarinatus (Dixon et al., 1993) and of the congener C. exoletus (Nogueira et al., 2013), as well as of several other species of South American snakes (Nogueira et al., 2013; Panzera and Maneyro, 2014; Gavira et al., 2015). Hemidactylus mabouia is an exotic species of African origin that is currently widespread in the Neotropics, where it is found mainly associated to anthropic and perianthropic environments (Kluge, 1969; Ávila-Pires 1995). The relatively small size and widespread presence of this lizard in tropical America make it a potential prey for many species of native snakes, especially those that are tolerant to anthropically disturbed habitats.

Acknowledgments

We thank Jéssica Barbosa for bringing the snake to the senior author, and Daniel Fernandes for the identification of the snake.

 

Literature cited

1.Ávila-Pires, T.C.S. 1995. Lizards of Brazilian Amazonia (Reptilia: Squamata). Zoologische Verhandelingen 299: 1-706.         [ Links ]

2. Bernarde, P.S. & Abe, A.S. 2010. Food habits of snakes from Espigão do Oeste, Rondônia, Brazil. Biota Neotropica 10: 167-173.         [ Links ]

3. Bovo, R.P. & Sueiro, L.R. 2012. Records of predation on Itapotihyla langsdorffii (Anura: Hylidae) by Chironius bicarinatus (Serpentes: Colubridae) with notes on foraging substrate. Herpetology Notes 5: 291-292.         [ Links ]

4. Carvalho-Silva, S.P. & Fernandes, R. 1994. Chironius bicarinatus. (NCN). Foraging behavior. Herpetological Review 25: 28.         [ Links ]

5. Dixon, J.R.; Wiest Jr., J.A. & Cei, J.M. 1993. Revision of the Neotropical snake genus Chironius Fitzinger (Serpentes, Colubridae). Monografie XIII, Mus. Region. Sci. Nat. Torino.         [ Links ]

6. Gavira, R.S.B.; Fabrício-Neto, A.& Andrade, D.V. 2015. Death of a juvenile false coral snake, Oxyrhopus guibei (Hoge & Romano, 1977) (Serpentes: Dipsadidae), after ingesting a tropical house gecko, Hemidactylus mabouia (Moreau de Jonnès, 1818) (Sauria: Gekkonidae). Herpetology Notes 8: 153-154.         [ Links ]

7. Hamdan, B. & Fernandes, D.S. 2015. Taxonomic revision of Chironius flavolineatus (Jan, 1863) with description of a new species (Serpentes: Colubridae). Zootaxa 4012: 97-119.         [ Links ]

8. Hartmann, P.A.; Hartmann, M.T. & Martins, M. 2009a. Ecology of a snake assemblage in the Atlantic Forest of southeastern Brazil. Papéis Avulsos de Zoologia, 49: 343-360.         [ Links ]

9. Hartmann, P.A.; Hartmann, M.T. & Martins, M. 2009b. Ecologia e história natural de uma taxocenose de serpentes no Núcleo Santa Virgínia do Parque Estadual da Serra do Mar, no sudeste do Brasil. Biota Neotropica, 9: 173-184.         [ Links ]

10. Hollis, J.L. 2006. Phylogenetics of the genus Chironius Fitzinger,1826 (Serpentes, Colubridae) based on morphology. Herpetologica 62: 435-453.         [ Links ]

11. Klaczko, J.; Montingelli, G.G. & Zaher, H. 2014. A combined morphological and molecular phylogeny of the genus Chironius Fitzinger, 1826 (Serpentes: Colubridae). Zoological Journal of the Linnean Society 171: 656-667.         [ Links ]

12. Kluge, A.G. 1969. The evolution and geographical origin of the New World Hemidactylus mabouia-brookii complex (Gekkonidae, Sauria). Miscellaneous Publications of the Museum of Zoology, University of Michigan 138: 1-78.         [ Links ]

13. Marques, O.A.V. & Sazima, I. 2004. Estação Ecológica Juréia-Itatins: ambiente físico, flora e fauna: 257-277. In: Marques, O.A.V. & Duleba, W. (eds.), História natural dos répteis da Estação Ecológica Juréia-Itatins. Holos, Ribeirão Preto, Brasil.         [ Links ]

14. Marques, O.A.V.; Muniz-da-Silva, D.F.; Barbo, F.E.; Travaglia Cardoso, S. R.; Maia, D.C. & Almeida-Santos, S. M. 2014. Ecology of the colubrid snake Spilotes pullatus from the Atlantic Forest of Southeastern Brazil. Herpetologica 70: 407-416.         [ Links ]

15. Nascimento, L.P.; Siqueira, D.M. & Santos-Costa, M.C. 2013. Diet, reproduction, and sexual dimorphism in the vine snake, Chironius fuscus (Serpentes: Colubridae), from Brazilian Amazonia. South American Journal of Herpetology, 8: 168-174.         [ Links ]

16. Nogueira, C.H.O; Figueiredo-de-Andrade, C.A. & Freitas, N.N. 2013. Death of a juvenile snake Oxyrhopus petolarius (Linnaeus, 1758) after eating an adult house gecko Hemidactylus mabouia (Moreau de Jonnès, 1818). Herpetology Notes 6: 39-43.         [ Links ]

17. Oliveira, S.V. 2008. Observação do comportamento predatório de Chironius bicarinatus (Serpentes, Colubridae) em Hypsiboas pulchellus (Anura, Hylidae), Serra do Sudoeste, Rio Grande do Sul, Brasil. Biodiversidade Pampeana 6: 1-3.         [ Links ]

18. Panzera, A. & Maneyro, R. 2014. Feeding biology of Lygophis anomalus (Dipsadidae, Xenodontinae). South American Journal of Herpetology 9:75-82.         [ Links ]

19. Pinto, R.R.; Fernandes, R. & Marques, O.A.V. 2008. Morphology and diet of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus (Serpentes: Colubridae). Amphibia-Reptilia 29: 149-160.         [ Links ]

20. Sazima, I. & Martins, M. 1990. Presas grandes e serpentes jovens: quando os olhos são maiores que a boca. Memórias do Instituto Butantan 52: 73-79.         [ Links ]

21. Zaher, H.; Grazziotin, F.G.; Cadle, J.E.; Murphy, R.W. & Moura-Leite, J.C. 2009. Molecular phylogeny of advanced snakes (Serpentes, Caenophidia) with an emphasis on South American Xenodontines: a revised classification and descriptions of new taxa. Papéis Avulsos de Zoologia 49: 115-153.         [ Links ]