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Habu snakes (Protobothrops flavoviridis) are pit vipers found in the geographically adjacent but ecologically divergent islands of Tokunoshima and Amami-Oshima in southwestern Japan. Abiotic factors can cause variation in animal populations between the two islands, and Habu snakes may show such intraspecific physiological variation. We therefore evaluated the vasoreactivity in aortas isolated from the Habu of both islands. Tokunoshima Habu showed significantly greater contractile responses to angiotensin (Ang) II, acetylcholine (ACh) and noradrenaline, and significantly higher affinities (pEC50) for Ang II and ACh, than Amami-Oshima Habu. ACh caused contractions in aortas from both populations, a finding previously unreported in snakes. Our findings indicate that vasoreactivity may differ between Tokunoshima and Amami-Oshima Habu. [ABSTRACT FROM AUTHOR]

Gloydius blomhoffii is a common pitviper distributed throughout Japan except for Okinawa Prefecture. To understand intraspecific geographic variation of this widely distributed snake, I describe several of its basic ecological traits observed during a 31-year-field survey conducted in the forest of Ashiu, northeastern Kyoto, in the western region of the mainland of Japan, and compare these traits with those reported in previous studies conducted in widespread areas of Japan. Body length of G. blomhoffii in Kyoto was smaller than that in the northernmost range and larger than that in the southernmost range. Sexual size dimorphism in snout-vent length, tail length, and body mass showed the same trends as in other areas. The sex ratio of the collected snakes was biased to females, which has not been observed in other studies. Pregnant females showed higher body temperature than males and non-pregnant females at a given air temperature. Parturition period, litter size, and body size of neonates generally overlapped with those reported in previous studies. Stomach contents were found only in 9.1% of snakes and consisted of rodents, frogs, and newts, which are prey items already known in G. blomhoffii. Although the forest in Ashiu has been incurred drastic environmental degradation, no obvious change in body size was detected over the study period. This study adds information on ecological traits of G. blomhoffii based on a population-level study and will facilitate future intensive field research to understand this common, but still poorly investigated, venomous snake endemic to Japan. [ABSTRACT FROM AUTHOR]

Resistance of hosts to ticks has important roles in their interactions. Ticks parasitize not only mammals, but also birds, reptiles and amphibians. Thus, a better understanding of their interaction requires studies of the resistance of various host taxa. We examined the presence of ticks engorged on three species of snakes, Gloydius tsushimaensis, Lycodon rufozonatus and Elaphe climacophora, on Tsushima Islands, Japan in 2017 and 2018. The rate of G. tsushimaensis parasitized by ticks was high (87.5%), but none of those ticks were engorged, and the frequency of live ticks on each snake was low (16.1 ± 5.4%). On the other hand, engorged ticks were found on L. rufozonatus and E. climacophora, and no dead ticks were observed on them. In addition, laboratory observation revealed that two of three ticks that had attached to G. tsushimaensis died within approximately 6 days after attaching, and the third did not engorge. Our results suggest that only G. tsushimaensis among the three snake species on the Tsushima Islands possesses strong host resistance to ticks. Our study suggests that host resistance in snakes may have considerable influence on tick and host populations and on transmission dynamics between them. [ABSTRACT FROM AUTHOR]

Protobothrops tokarensis ( Pt ), a Crotalinae snake, inhabits only Takarajima and Kodakarajima islands of the Tokara Islands located in the immediate north of Amami-Oshima island of Japan. Kodakarajima P . tokarensis venom gland cDNA library gave four types of phospholipase A 2 (PLA 2 ) cDNAs encoding neutral [Asp 49 ]PLA 2 , basic [Asp 49 ]PLA 2 , highly basic [Asp 49 ]PLA 2 , and [Lys 49 ]PLA 2 . As the amino acid sequences encoded by their open reading frames (ORFs) were identical to those of PLA2, PLA-B, PLA-N, and BPI (a [Lys 49 ]PLA 2 ), respectively, from Amami-Oshima P. flavoviridis ( Pf ) venom, they were named Pt PLA2, Pt PLA-B, Pt PLA-N, and Pt BPI. Chromatography of P . tokarensis venom gave three PLA 2 isozymes, Pt PLA2, Pt PLA-B, and Pt BPI. However, BPII and BPIII ([Lys 49 ]PLA 2 s) expressed in Amami-Oshima P . flavoviridis venom were not found in P . tokarensis venom. Genomic polymerase chain reaction (PCR) for P . tokarensis liver DNAs with the unique primers gave Pt BPI gene. Notably it was found that LINE (long interspersed nuclear element)-1 fragment is inserted into second intron of Pt BPI gene. The LINE-1 fragment may prevent duplication of Pt BPI gene and thus formation of plural [Lys 49 ]PLA 2 genes in P . tokarensis genome. The interisland variegation of venom [Lys 49 ]PLA 2 isozyme genes in Protobothrops genus snakes in the southwestern islands of Japan is discussed. [ABSTRACT FROM AUTHOR]

Ovophis okinavensis is an endemic pitviper of the subtropical region of Japan. Based on information from various localities, the species has been considered a dietary generalist that exploits various terrestrial vertebrates. We analyzed stomach contents of O. okinavensis in a northern mountain area on Okinawa Island, based on data of a 10-years-study, to examine its trophic features at the population level. We recovered a total of 461 prey items, which were comprised of six, three, five, and three species of frogs, reptiles, birds, and mammals, respectively. Approximately 93% of dietary items consisted of frogs, the majority of which belonged to two explosively breeding species aggregating to restricted spots along the stream only during their reproductive season (winter). On the other hand, from April to November, the snake mainly depended on vertebrates other than frogs. Neither an ontogenetic dietary shift nor intersexual dietary divergence was evident although males tended to exploit one of the two explosively breeding frog species more frequently than females. There were weak positive correlations between snake size and prey size, but large snakes did not drop small prey items from their diet. Average body mass of each prey item was only 5.2% of snake body mass. Characteristics of trophic features of O. okinavensis of this population, such as extremely high dependency on frogs in winter, the absence of ontogenetic dietary shift, and utilization of small sized prey, are discussed in comparison with other viperids. [ABSTRACT FROM AUTHOR]

Abstract: In search of the transcripts expressed in Protobothrops flavoviridis venom gland, 466 expressed sequence tags (ESTs) were generated from the venom gland cDNA library of P. flavoviridis in Amami–Oshima, Japan. The sequencing of randomly selected cDNA clones followed by identification in similarity search against existing databases led to the finding of a novel lysine-49-phospholipase A2 ([Lys49]PLA2) clone. It coded for one amino acid-substituted BPII homologue or two amino acids-substituted BPI homologue in which BPII and BPI are [Lys49]PLA2s contained in Amami–Oshima and Tokunoshima P. flavoviridis venoms. This isozyme, named BPIII, was isolated from Amami–Oshima P. flavoviridis venom. BPIII gave a specific [M+2H]2+ peak of m/z 736.3 on mass spectrometry (MS) analysis after S-carboxamidomethylation and trypsin digestion when compared with BPII. It became evident from MS analysis after S-carboxamidomethylation and trypsin digestion of the mixed protein peaks ranging from BPI to BPII obtained by fractionation on a carboxymethyl cellulose column of Amami–Oshima and Tokunoshima P. flavoviridis venoms that BPIII protein is contained in Amami–Oshima P. flavoviridis venom but not in Tokunoshima P. flavoviridis venom. It is for the first time that a protein present in Amami–Oshima P. flavoviridis venom is not found in Tokunoshima P. flavoviridis venom. [Copyright &y& Elsevier]

Feeding performance (handling time, capture success) in numerous animal species is well known to be influenced by a variety of ecological, functional, and physiological factors. Nonetheless, few studies have tested which factors are the strongest determinants of animal feeding performance in the wild. Using a field-based experiment, we examined the relationships among a number of functionally important variables and the predatory behaviour of free-ranging pit-vipers ( Ovophis okinavensis) from Okinawa Island, Japan. Our main findings were: (1) strike latency was negatively related to snake body temperature and, hence, hotter snakes struck at frogs more readily than colder snakes; (2) initial bite position was correlated with ingestion direction (headfirst versus hindfirst) but ingestion direction was not correlated with ingestion duration; and (3) both snake head length and body temperature were negatively related with ingestion duration and, thus, snakes with longer heads and higher body temperatures had shorter ingestion durations. In O. okinavensis, head size and body temperature are therefore likely to have direct ecological consequences in terms of its feeding rate on explosively breeding frogs. More generally, however, this field-based study adds to the growing body of literature demonstrating that temperature has a pervasive influence on the feeding performance of ectotherms in general. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 53–62. [ABSTRACT FROM AUTHOR]