Biotope, manners and adaptation

Introduction

In situ, Trimeresurus are present throughout Asia. Some species are endemic, have a relatively small distribution range with a biotope that varies very little, while others will have a wider geographical area, sometimes crossing certain borders. While the majority of species are arboreal, some are almost exclusively terricolous as is the case for Trimeresurus gracilis (Tu, MC, Wang, HY, Tsai, MP, Toda, M, Lee, WJ, Zhang, FJ, & Ota). , H. (2000)), which can go as far as semi-aquatic behavior as observed among other things on Craspedocephalus malabaricus with apnea durations observed between 1 and 15 minutes. (BHAISARE, D., & PELLING, E. (2015)).

Beyond taxonimy, it is possible to refer to some authors who sometimes classify the species of the complex in 3 categories: green, green + others, others. Non-green (other) species are also regularly called “primitive”, especially since phylogenetic studies on Craspedocephalus borneensis and Craspedocephalus puniceus (Wang, YM, Peng, HF, & Tsai, IH (2005)) but also on mimicry studies. Müllerien in the complex (Sanders, KL, Malhotra, A., & Thorpe, RS (2006)). The latter has a significant capital in the survival of species whether in the camouflage of predators or prey, but also in thermoregulation, which could among other things explain why some localities including Craspedocephalus trigonocephalus have black strips in wetlands and do not have them in drier areas. (Sanders, K. L., Malhotra, A., & Thorpe, R. S. (2006), Wilson, D., Heinsohn, R., & Wood, J. (2006), NADEGURA.com).

Biotop

  • Ghâts occidentaux - 28 mai - avant la mousson - Lieu de vie du Trimeresurus (Craspedocephalus) malabaricus - Wikipedia

Although complex species such as Trimeresurus albolabris can be found in towns or fields, the majority of Trimeresurus live in or near forests. At this point, their sea-level rise ranges from 0m to over 3’500m, as some sources say for Trimeresurus septentrionalis. The majority, however, runs between 600m and 1’500m above sea level (Orlov, N.I. K. O.L.I., Ananjeva, N.A.A.L.I.A., & Khalikov, R.O.M.A.A.N. (2002), snakedatabase, iucnredlist, wikipedia). Forests are varied and their floral diversity depends on altitude, temperatures and seasons. The density of vegetation also influences the presence of species. Thus, while it is possible to find species such as Viridovipera stejnegeri or Trimeresurus albolabris in open spaces, other species, such as Craspedocephalus gramineus and Craspedocephalus Malabaricus prefer denser vegetation. The wide habitat, and therefore the different biotopes possible of individuals of the same species allows, among other things, to explain the differences of polymorphisms. Apart from cultivable fields, some species, such as Trimeresurus purpureomaculatus live in mangroves such as Avicennia marina or mangroves. Mangroves are very productive biomes (ecozones) that offer homes sheltered from the light, covered by the canopy (Kurniawan, N., Priambodo, B., Nugraha, F. A. D., Maulidi, A., & Kurnianto, A. S. (2017)).

Mangrove - Trimeresurus purpureomaculatus - Credit - Wikipedia
Mangrove – Trimeresurus purpureomaculatus – Credit – Wikipedia

The different species have been observed in, or close to, elements such as those presented in the following table:

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Naturals supports
Streblus ilicifolius Corner
Calamus longisetus
Daemonorops spp
Rinorea sp
Hoya spp
Gigantochloa compressa
Syzygium spp
Rhizophora sp
Kandelia sp
Rhizophoraceae sp
Avicennia marina
Calamus longisetus Griff
Daemonorops spp
Ormosia travancorica

Manners

Significant studies on Viridovipera stejnegeri, a tree species, have shown that sexual dimorphism, however important, has no influence on the selection of branches, whose diameter rarely exceeded 2cm (Tu, MC, Wang, S., & Lin , YC (2000)). This study also demonstrated 2 interesting points. At first, it confirms other studies on arboreal species not referenced here, when the mode of vertical displacement between day and night. In a second step, there is a difference between the species caught and maintained in the outer enclosure at the height of the branches used. The species studied in the field tend to be perched lower (less than 4m from the ground) than the species kept in the enclosure (more than 4m from the ground). Moreover, the height selected by individuals have an obvious correlation with temperature. Indeed, if during the day they go down near the ground in search of freshness, Viridovipera stejnegeri, among others, will retreat into denser vegetation, offering better shading, when the temperature will exceed 25 ° C. The aforementioned species hunting both terrestrial and tree prey, the distance between any prey, and the place of retreat has no apparent links (Lin, H. C., Hung, H. Y., Lue, K. Y., & Tu, M. C. (2007)).

Trimeresurus albolabris is the most widespread species of the complex. It is found at different altitudes and sometimes close to cities, such as Hong Kong where it is considered a nuisance (Devan-Song, E. A. (2014)). Beyond this aspect, and still in this locality, Trimeresurus albolabris lives in terrestrial vegetations (rarely higher than 50cm), although these factors are clearly influenced by the seasons (Myint, K., & Zaw, KM M (2011 )). This same study has demonstrated, always on the aforementioned species, a change of height caused by the hunter aspect of the Trimeresurus. As night falls, and observed as early as 5:00 pm, Trimeresurus albolabris were seen growing from 90cm to 135cm tall in the bushes at 45cm or 15cm high at 23:00. However, the study did not show any results on the reverse behavior, the rise in the branches in the early morning.

In Laos, observations of Viridovipera stejnegeri were made in September 2012 and August 2013. They also confirm that the species seldom exceed one meter and fifty of the soil since the 5 individuals photographed were between this culminating point and 30 cm from the ground (PiQueT, A., LOTTER, A., & DAviD, P. (2014)). These observations were made a few years earlier also, in 2002, among others on Popeia popeiorum (Orlov, N. I. K. O. L. A. I., Ananjeva, N. A. T. A. L. I. A., & Khalikov, R. O. M. A. N. (2002)).

Craspedocephalus malabaricus is one of the few species of the complex to have terricolous habits and has been observed in apnea. In addition, adults behave differently from juveniles. Where they like significantly cooler temperatures and are mainly terrestrial. Sub-adults and adults are visible in the sun during the day and hunting at night, their tendency is slightly more terrestrial. It is also one of the only species of the genus Trimeresurus to experience 2 color changes, influenced by age and season (Sagar, U. (2016)).

Rare observation, that of a Peltopelor macrolepis more than 20m above the ground and dated 2012 (SESHADRI, Kadaba Shamanna).

Several radio-telemetry studies (Devan-Song, E. A. (2014)) and localized observations have demonstrated the importance of not relocating individuals. The authors of the sites herpingthailand.com noted the observation of a Trimeresurus albolabris that returned to its place of origin when they moved it from 20 to 40m:

These Trimeresurus albolabris vipers (I suppose like most snakes, but at least with this species I have personally observed it) seem to know their way around their homerange. When I relocated a specimen out of the garden of some family in Eastern Thailand the specimen was back at the exact same spot a day after. I only had moved it for like 20m in a bush outside of the garden but anyway. I repeated this once more, this time moved it maybe 30 – 40m. And again a day later it was back at her favorite spot. This time less visible, so I decided to leave it there.

 

Adaptation

With such a wide distribution of air, the complex has also evolved at different altitudes and has adapted to the meteorological parameters of each of these regions. For example, the city of Hong Kong, China, whose highest point is located at 958m altitude (the mountain of the Big Hat, “Tai Mo Shan”), where one can find among others Trimeresurus albolabris, undergoes regularly strong monsoons, explained by its subtropical climate. A dry winter spanning from January to March and the summer is hot wet see rainy. Spring and autumn are not very marked and temperatures are rising and falling respectively at 36.1 ° C and 0 ° C. The humidity varies seasonally from 70% to over 90%.

Fujian, which is an hour and a half north of Hong Kong, is a mountainous region where species such as Trimeresurus insularis can be found among other things. It also has a warm climate in summer, but mild winters. The region does not have a dry climate and the annual temperature seems relatively constant, around 20.4 ° C.

Unlike the two regions above, we can also talk about the tremendous adaptation that species of the genus Trimeresurus have. For example, Himalayophis tibetanus, found in Nepal but also in Tibet, lives perfectly in sometimes extreme conditions. Indeed, in Tibet, whose average altitude is around 4’200m has a continental climate whose temperatures can undergo great variations from one day to another, winning or losing several tens of degrees.

In India, where climates are influenced by the Himalayas to the north and by the Thar Desert further south, is home to a good dozen species of the complex and has, depending on the region, a desert territory whose maximum temperatures can go up to at 33 ° C and down to 18.7 ° C, a milder alpine climate, where the maximum and minimum temperatures are 7.3 ° C and 19.7 ° C, and finally, a humid tropical climate, governed by oscillating temperatures between 24 ° C and 30 ° C.

In South Asia, the monsoon occurs from December to March with winds coming from the northeast. In winter the temperature in central Asia is below 25 ° C, creating an anticyclone in the region. The jet stream in this region is divided into a subtropical branch and a polar branch. The first breath, mostly from the northeast, bringing dry air to India and South Asia. At the same time, a low pressure system is developing in Southeast Asia and Australasia, whose winds are directed towards Australia, forming a barometric trough where moisture converges (Wikipedia, March 2017).

Temperature changes, however, do not appear to be determining factors in the acclimation of species to any altitude level. In 2007, a study carried out on Viridovipera stejnegeri, 2 lowland species and Trimeresurus gracilis, living at altitude, after 2 weeks of acclimation, demonstrated that their ability to acclimate to temperature variations (10, 20 and 30 ° C) did not allow altitude to be defined as a factor limiting their distributions (Huang, S. M., Huang, S. P., Chen, Y. H., & Tu, M. C. (2007)).

asian-pitvipers.com | Les Ghâts, en Inde - crédit: Hiren Khatri
The Ghats, India, crédit: Hiren Khatri

Sources:

Tu, M. C., Wang, H. Y., Tsai, M. P., Toda, M., Lee, W. J., Zhang, F. J., & Ota, H. (2000). Phylogeny, taxonomy, and biogeography of the oriental pitvipers of the genus Trimeresurus (Reptilia: Viperidae: Crotalinae): a molecular perspective. Zoological Science, 17(8), 1147-1157.

Sanders, K. L., Malhotra, A., & Thorpe, R. S. (2006). Evidence for a Müllerian mimetic radiation in Asian pitvipers. Proceedings of the Royal Society of London B: Biological Sciences, 273(1590), 1135-1141.

Wilson, D., Heinsohn, R., & Wood, J. (2006). Life‐history traits and ontogenetic colour change in an arboreal tropical python, Morelia viridis. Journal of Zoology, 270(3), 399-407.

BHAISARE, D., & PELLING, E. (2015). Trimeresurus malabaricus (Malabar pit viper): Diving behaviour and underwater apnoea duration. Herpetological Bulletin, 134, 33-34.

Tu, M. C., Wang, S., & Lin, Y. C. (2000). No divergence of habitat selection between male and female arboreal snakes, Trimeresurus s. stejnegeri. ZOOLOGICAL STUDIES-TAIPEI-, 39(2), 91-98.

Lin, H. C., Hung, H. Y., Lue, K. Y., & Tu, M. C. (2007). Diurnal retreat site selection by the arboreal Chinese green tree viper (Trimeresurus s. stejnegeri) as influenced by temperature. ZOOLOGICAL STUDIES-TAIPEI-, 46(2), 216.

Devan-Song, E. A. (2014). Ecology and conservation of the bamboo pit viper: Natural history, demography and effects of translocation.

PiQueT, A., LOTTier, A., & DAviD, P. (2014). Amphibiens et Reptiles du Laos: nouvelles données nationales et provinciales. Bull. Soc. Herp. Fr, 151, 21-52.

Myint, K., & Zaw, K. M. M. Some Ecological Aspects of White-lipped Pit Viper, Trimeresurus albolabris Gray 1842 in Yangon University Campus. Universities Research Journal, 2255.

Orlov, N. I. K. O. L. A. I., Ananjeva, N. A. T. A. L. I. A., & Khalikov, R. O. M. A. N. (2002). Natural history of pitvipers in Eastern and Southeastern Asia. Biology of the Vipers, 345-361.

Sumontha, M., Kunya, K., Pauwels, O. S., Nitikul, A., & Punnadee, S. (2011). Trimeresurus (Popeia) phuketensis, a new pitviper (Squamata: Viperidae) from Phuket island, southwestern Thailand. Russian Journal of Herpetology, 18(3), 185-194.

Sawant, N. S., & Jadhav, T. D. (2013). Factors Influencing Habitat Selection by Arboreal Pit Vipers. Zoological science, 30(1), 21-26.

Sagar, U. (2016). Some observations on the Malabar Pit Viper Trimeresurus malabaricus in central Western Ghats, India. Newsletter of the South Asian Reptile Network, 18, 36.

Huang, S. M., Huang, S. P., Chen, Y. H., & Tu, M. C. (2007). Thermal Tolerance and Altitudinal Distribution of Three Trimeresurus Snakes(Viperidae: Crotalinae) in Taiwan. Zoological Studies, 46(5), 592-599.

Kurniawan, N., Priambodo, B., Nugraha, F. A. D., Maulidi, A., & Kurnianto, A. S. (2017). Microhabitat Assessment of Mangrove Pit Viper Cryptelytrops purpureomaculatus in Restricted Mangrove Area, Dumai, Riau Province, Sumatera. Journal of Tropical Life Science, 7(2), 91-94.

SESHADRI, Kadaba Shamanna. Occurrence of large-scaled pit viper Trimeresurus macrolepis Beddome, 1862 in the forest canopy of Kalakad Mundanthurai Tiger Reserve, southern India.

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