Sexual dimorphism and reproductive biology of commercially harvested oriental rat snakes (Ptyas mucosa: Colubridae) from West Java

Amir Hamidy; Evy Arida; Noor Laina Maireda; Alamsyah Elang Nusa Herlambang; Awal Riyanto; Mumpuni; Richard Shine; Daniel J. D. Natusch

doi:10.1071/ZO23030

RESEARCH ARTICLE (Open Access)

Sexual dimorphism and reproductive biology of commercially harvested oriental rat snakes (Ptyas mucosa: Colubridae) from West Java

Amir Hamidy ^A , Evy Arida ^B , Noor Laina Maireda ^C , Alamsyah Elang Nusa Herlambang ^A , Awal Riyanto ^A , Mumpuni ^A , Richard Shine ^D and Daniel J. D. Natusch

^D ^*

+ Author Affiliations

- Author Affiliations

^A Laboratory of Herpetology, Museum Zoologicum Bogoriense, Research Center for Biosystematics and Evolution, Organization for Research of Life Sciences and Environment, Research and Innovation Agency of Indonesia, Gd. Widyasatwaloka, KST Soekarno, Jl. Raya Jakarta-Bogor Km 46, Cibinong, West Java, Indonesia.

^B Research Center for Applied Zoology, Organization for Research of Life Sciences and Environment, Research and Innovation Agency of Indonesia, Gd. Widyasatwaloka, KST Soekarno, Jl. Raya Jakarta-Bogor Km 46, Cibinong, West Java, Indonesia.

^C Indonesian Herpetological Society (Penggalang Herpetologi Indonesia/PHI), Departemen KSDHE, Fakultas Kehutanan IPB, Jl. Ulin, Kampus IPB Dramaga, Bogor, West Java 16680, Indonesia.

^D School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia.

^* Correspondence to: d.natusch@epicbiodiversity.com

Handling Editor: Paul Cooper

Australian Journal of Zoology 72, ZO23030 https://doi.org/10.1071/ZO23030

Submitted: 22 August 2023 Accepted: 3 April 2024 Published: 3 May 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Large (>3 m) slender-bodied rat snakes are abundant in agroecosystems of southern Asia and are heavily exploited for their skins and meat. We examined 216 specimens killed at commercial facilities in Cirebon, West Java, to quantify morphological and reproductive traits and evaluate harvest sustainability by comparing this sample to one taken 25 years previously. The snakes we examined were mostly adults, and mostly male. Females were less heavy-bodied than males of the same body length, matured at a larger size than males, but attained smaller maximum sizes. Reproduction and energy (fatbody) storage was seasonal in both sexes, with females containing oviductal eggs primarily during the annual wet season. Clutch size averaged 12.6 eggs and increased with maternal body size. Comparison of the two samples taken 25 years apart revealed strong similarity in sex ratio, the numerical preponderance of adults, body sizes at sexual maturation and mean adult body sizes, sexual dimorphism in body length and mass, reproductive seasonality in females, mean fecundity, and the relationship between fecundity and maternal body size. That consistency suggests that commercial harvesting over the intervening period has not affected the biological traits of rat snake populations, consistent with a sustainable level of offtake.

Keywords: Colubridae, Indonesia, reproductive cycles, snake ecology, sustainability, tropical, utilisation, wildlife trade.

References

Auliya M (2010) ‘Conservation status and impact of trade on the oriental rat snake Ptyas mucosa in Java, Indonesia.’ (TRAFFIC Southeast Asia: Petaling Jaya, Selangor, Malaysia)

Bergman RAM (1952) L’anatomie du genre Ptyas a Java. Rivista di Biologia Coloniale Roma 12, 1-42.
| Google Scholar |

Boeadi , Shine R, Sugardjito , Amir M, Sinaga MH (1998) Biology of the commercially-harvested ratsnake (Ptyas mucosus) and cobra (Naja sputatrix) in central Java. Mertensiella 9, 99-104.
| Google Scholar |

Bonnet X, Shine R, Naulleau G, Vacher-Vallas M (1998) Sexual dimorphism in snakes: different reproductive roles favour different body plans. Proceedings of the Royal Society. Series B: Biological Sciences 265, 179-183.
| Crossref | Google Scholar |

Brown GP, Shine R (2002) Reproductive ecology of a tropical natricine snake, Tropidonophis mairii (Colubridae). Journal of Zoology 258(1), 63-72.
| Crossref | Google Scholar |

Brown GP, Shine R (2006) Why do most tropical animals reproduce seasonally? Testing hypotheses on an Australian snake. Ecology 87, 133-143.
| Crossref | Google Scholar | PubMed |

Camera BF, Quintana I, Strüssmann C, Waller T, Barros M, Draque J, Micucci PA, Miranda EBP (2020) Assessing the sustainability of yellow anaconda (Eunectes notaeus) harvest in northeastern Argentina. PLoS ONE 18(1), e0277629.
| Crossref | Google Scholar |

Carpenter CC (1986) An inventory of combat rituals in snakes. Smithsonian Herpetological Information Service 69, 1-18.
| Crossref | Google Scholar |

Fitzgerald LA (1994) The interplay between life history and environmental stochasticity: implications for the management of exploited lizard populations. American Zoologist 34(3), 371-381.
| Crossref | Google Scholar |

Harlow PS, Taylor JE (2000) Reproductive ecology of the jacky dragon (Amphibolurus muricatus): an agamid lizard with temperature-dependent sex determination. Austral Ecology 25(6), 640-652.
| Crossref | Google Scholar |

Kopstein F (1938) Ein Beitrag zur Eierkunde und zur Fortpflanzung der Malaiischen Reptilien. The Raffles Bulletin of Zoology 14, 81-167.
| Google Scholar |

Kurniawan N, Nugraha FA, Maulidi A, Firdaus AS, Kadafi AM, Kurnianto AS (2018) Snapshot of an on-going trade in reptile wholesaler, Kebumen, Central Java: preparation, trading, and conservation implications. Indonesian Journal of Environment and Sustainable Development 9, 9-14.
| Google Scholar |

Kusrini MD, Manurung R, Habiburrahman Faz A, Dwiputro A, Tajalli A, Nur Prasetyo H, Bayu Saputra P, Kennedi UF, Parikesit DW, Shine R, Natusch D (2022) Abundance, demography, and harvesting of water snakes from agricultural landscapes in West Java, Indonesia. Wildlife Research 50(4), 272-282.
| Crossref | Google Scholar |

Mieres MM, Fitzgerald LA (2006) Monitoring and managing the harvest of tegu lizards in Paraguay. Journal of Wildlife Management 70(6), 1723-1734.
| Crossref | Google Scholar |

Murphy JC (2007) ‘Homalopsid snakes. Evolution in the Mud.’ (Kreiger: Melbourne, FL, USA)

Natusch DJD, Lyons JA, Mumpuni , Riyanto A, Shine R (2016) Jungle giants: assessing sustainable harvesting in a difficult-to-survey species (Python reticulatus). PLoS ONE 11(7), e0158397.
| Crossref | Google Scholar | PubMed |

Natusch DJD, Lyons JA, Riyanto A, Mumpuni , Khadiejah S, Shine R (2019) Detailed biological data are informative, but robust trends are needed for informing sustainability of wildlife harvesting: a case study of reptile offtake in Southeast Asia. Biological Conservation 233, 83-92.
| Crossref | Google Scholar |

Natusch DJD, Lyons JA, Mumpuni , Riyanto A, Shine R (2020) Harvest effects on blood pythons in North Sumatra. The Journal of Wildlife Management 84, 249-255.
| Crossref | Google Scholar |

Pal A, Dey S, Roy US (2012) Seasonal diversity and abundance of herpetofauna in and around an industrial city of West Bengal, India. Journal of Applied Sciences in Environmental Sanitation 7, 281-286.
| Google Scholar |

Pope CH (1935) ‘The reptiles of China: turtles, crocodilians, snakes, lizards.’ (American Museum of Natural History: New York, NY, USA)

Shine R (1994) Sexual size dimorphism in snakes revisited. Copeia 1994, 326-346.
| Crossref | Google Scholar |

Shine R, Ambariyanto , Harlow PS, Mumpuni (1999) Reticulated pythons in Sumatra: biology, harvesting and sustainability. Biological Conservation 87(3), 349-357.
| Crossref | Google Scholar |

Sidik I (2006) Analisis Isi Perut Dan Ukuran Tubuh Ular Jali (Ptyas mucosus). Zoo Indonesia. Jurnal Fauna Tropika 15(2), 121-127.
| Google Scholar |

Sugardjito J, Boeadi , Amir M, Sinaga MH (1998) Assessment of harvest levels and status of the spitting cobra (Naja sputatrix) and the rat snake (Ptyas mucosus) in Central Java. Mertensiella 9, 105-110.
| Google Scholar |

Titley MA, Snaddon JL, Turner EC (2017) Scientific research on animal biodiversity is systematically biased towards vertebrates and temperate regions. PLoS ONE 12(12), e0189577.
| Crossref | Google Scholar | PubMed |

Wall F (1921) ‘Snakes of Ceylon.’ (H. R. Cottle, Government Printer: Ceylon)