The Experts below are selected from a list of 732 Experts worldwide ranked by ideXlab platform
Michael R. Kearney - One of the best experts on this subject based on the ideXlab platform.
-
A radiotelemetric study of movements and thermal biology of insular Chinese pit-vipers (Gloydius shedaoensis, Viperidae)
Oikos, 2003Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Because of their low metabolic costs, ectothermic predators can specialise on prey resources that are available for only a brief period each year. Endemic pit-vipers (Gloydius shedaoensis) on a small island in north-eastern China offer an extreme example of this phenomenon, with adult snakes feeding only on seasonally migrating birds that are available for a few weeks in spring and autumn. We surgically implanted radiotransmitters in 16 pit-vipers, and located the snakes at weekly intervals for the next 12 months to record activity, movements, home ranges, habitat use, body temperatures and associated environmental temperatures. The snakes were extremely sedentary, with daily displacements averaging
-
Antipredator Responses of Free-Ranging Pit Vipers(Gloydius shedaoensis, Viperidae)
Copeia, 2002Co-Authors: Richard Shine, Mark Fitzgerald, Michael R. KearneyAbstract:Abstract Few quantitative data are available on the ways in which venomous snakes respond to humans. We took advantage of extraordinarily high numbers of endemic pit vipers on the small island of Shedao in northeastern China, to quantify snake responses. We approached free-ranging pit vipers in their ambush sites (either in trees or on the ground) and recorded their behavior. The snakes' responses to our approach depended upon (1) the intensity of the stimulus; (2) attributes of the snake (size class, body temperature, whether it had fed recently); and (3) the snake's location (in an arboreal or terrestrial site). Most snakes tolerated close approach. Juvenile pit vipers struck more often than adults, and warmer snakes were more likely to flee, display, or strike rather than rely on crypsis. Snakes on the ground were more likely to flee or strike than were those in trees. Many of the same patterns were seen in our laboratory trials. For example, striking was more frequent in juveniles than adults, in hott...
-
Accidental altruism in insular pit-vipers (Gloydius shedaoensis, Viperidae)
Evolutionary Ecology, 2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds' carcasses. Second, large snakes kill raptorial birds (spar- rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this 'accidental altruism' may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao.
Richard Shine - One of the best experts on this subject based on the ideXlab platform.
-
A radiotelemetric study of movements and thermal biology of insular Chinese pit-vipers (Gloydius shedaoensis, Viperidae)
Oikos, 2003Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Because of their low metabolic costs, ectothermic predators can specialise on prey resources that are available for only a brief period each year. Endemic pit-vipers (Gloydius shedaoensis) on a small island in north-eastern China offer an extreme example of this phenomenon, with adult snakes feeding only on seasonally migrating birds that are available for a few weeks in spring and autumn. We surgically implanted radiotransmitters in 16 pit-vipers, and located the snakes at weekly intervals for the next 12 months to record activity, movements, home ranges, habitat use, body temperatures and associated environmental temperatures. The snakes were extremely sedentary, with daily displacements averaging
-
Antipredator Responses of Free-Ranging Pit Vipers(Gloydius shedaoensis, Viperidae)
Copeia, 2002Co-Authors: Richard Shine, Mark Fitzgerald, Michael R. KearneyAbstract:Abstract Few quantitative data are available on the ways in which venomous snakes respond to humans. We took advantage of extraordinarily high numbers of endemic pit vipers on the small island of Shedao in northeastern China, to quantify snake responses. We approached free-ranging pit vipers in their ambush sites (either in trees or on the ground) and recorded their behavior. The snakes' responses to our approach depended upon (1) the intensity of the stimulus; (2) attributes of the snake (size class, body temperature, whether it had fed recently); and (3) the snake's location (in an arboreal or terrestrial site). Most snakes tolerated close approach. Juvenile pit vipers struck more often than adults, and warmer snakes were more likely to flee, display, or strike rather than rely on crypsis. Snakes on the ground were more likely to flee or strike than were those in trees. Many of the same patterns were seen in our laboratory trials. For example, striking was more frequent in juveniles than adults, in hott...
-
Accidental altruism in insular pit-vipers (Gloydius shedaoensis, Viperidae)
Evolutionary Ecology, 2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds' carcasses. Second, large snakes kill raptorial birds (spar- rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this 'accidental altruism' may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao.
-
Arboreal ambush site selection by pit-vipers Gloydius shedaoensis
Animal Behaviour, 2002Co-Authors: Richard Shine, Sun Li-xinAbstract:For a sit-and-wait predator, the choice of ambush site may be a crucial determinant of foraging success. During fieldwork on a small island in northeastern China, we explored the availability and use of arboreal ambush sites (tree branches) selected by Shedao pit-vipers, Gloydius shedaoensis. The snakes were highly selective at a variety of spatial scales. For example, they displayed strong biases in terms of which tree species were used, which individual trees within each species were used and which branches were used within a tree. Snakes disproportionately used trees that were on the edge rather than the interior of thickets, and branches that faced out towards the clearing rather than back towards the thicket. Branches at an angle slightly above horizontal were preferred. The snakes used branches visited at high rates by potential prey, that provided effective camouflage, and with thermal and visual backgrounds (cool, bright) that contrasted strongly with avian prey items (hot, dark). The snakes used perches close to the ground (the area of greatest bird activity) despite suboptimal visual and thermal backgrounds. Use of thicker branches by larger snakes, and by snakes containing recently ingested prey items, may contribute to effective camouflage. Thermoregulation did not appear to influence foraging site selection.
-
Research article Accidental altruism in insular pit-vipers (Gloydius
2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael KearneyAbstract:Abstract. Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds ’ carcasses. Second, large snakes kill raptorial birds (spar-rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this ‘accidental altruism ’ may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao
Innho Tsai - One of the best experts on this subject based on the ideXlab platform.
-
Tracing the evolution of venom phospholipases A2 in Gloydius strauchii and related pitvipers: A tale of two acidic isozymes.
Toxicon : official journal of the International Society on Toxinology, 2017Co-Authors: Zhang-min Yang, Ying-zhe Xie, Su-xian Yan, Zhen-zhen Liu, Jian-cheng Song, Zhe-zhi Wang, Innho TsaiAbstract:Two acidic Asp49-PLA2s with Glu6 substitution and a neutral Lys49-PLA (designated Gst-K49) were cloned from G. strauchii venom glands, their full amino acid sequences were deduced. The predominant acidic PLA2 (designated Gst-E6a) contains 124 residues and the M18W30 substitutions, while the minor acidic PLA2 (designated Gst-E6b) contains 122 residues and the V18A30 substitutions. Their sequences are most similar to those of the respective orthologous PLA2s of G. intermedius venom. Gst-E6a and Gst-E6b appear to be paralogs and possibly have different predatory targets or functions. The LC-MS/MS results indicate the presence of only three PLA2 gene products in the crude venom, the relative expression levels were in the order of Gst-E6a ≫ Gst-E6b > Gst-K49, as confirmed by qPCR results. In contrast to other Gloydius, G. strauchii venom does not contain neurotoxic or basic anticoagulant Asp49-PLA2s, but Gst-K49 is the first Lys49-PLA2 identified in Gloydius venoms. However, its venom content is relatively low and its pI value 7.3 is much lower than those of other Lys49-PLA2s and. The Lys49-PLA2 genes appear to regress in the venom of most of Gloydius and related rattlesnake, and this evolutionary regression occurred before the dispersal of Asian pitvipers to the New World.
-
transcriptome and proteome of the highly neurotoxic venom of Gloydius intermedius
Toxicon, 2015Co-Authors: Zhang-min Yang, Yingming Wang, Zhe-zhi Wang, Yu Chen, Xu-min Wang, Yue Yang, Jing Cao, Cui Zhang, Lingling Liu, Innho TsaiAbstract:The venomics of Gloydius intermedius were investigated using expressed sequence tags (ESTs) analyses, 2D gel-electrophoresis combined with MALDI-TOF/TOF, and LC-MS/MS. A total of 1920 ESTs from the venom gland cDNA library were sequenced; 74% of them belonged to toxin-families. The four most abundant families among the toxin transcripts were: serine protease (SP, 36.2%), bradykinin potentiating peptide (25.3%), l-amino acid oxidase (LAAO, 13.1%), and phospholipase A2 (PLA2, 9.9%). Moreover, the full sequences of four PLA2s, eight SPs, cysteine-rich secretory protein (CRISP), C-type-lectin-like-protein (CTLP), hyaluronidase, metalloproteinase, and nerve growth factor were deduced from the cDNA sequences. Excluding the CRISP and hyaluronidase, most of the G. intermedius venom proteins bear 92-99% sequence identities to those of other pitviper venoms. The most abundant components are PLA2s (37%), SPs (20%) and LAAO (6%), while metalloproteinase, CTLP, and other components each account for <3% of the total venom proteins. The abundance of Gintexin (a crotoxin-like neurotoxin) and low levels of hemorrhagic metalloproteases, disintegrins and CTLPs highlight the great venom differences between G. intermedius and other hemorrhagic pitvipers. The bimorphism of hemorrhagic and neurotoxic venoms among Gloydius is confirmed; our results shed more lights on the co-evolution of both neurotoxicity and hypotension in some viperid venoms.
-
Transcriptome and proteome of the highly neurotoxic venom of Gloydius intermedius
Toxicon : official journal of the International Society on Toxinology, 2015Co-Authors: Zhang-min Yang, Yingming Wang, Zhe-zhi Wang, Yu Chen, Xu-min Wang, Yue Yang, Jing Cao, Cui Zhang, Lingling Liu, Innho TsaiAbstract:The venomics of Gloydius intermedius were investigated using expressed sequence tags (ESTs) analyses, 2D gel-electrophoresis combined with MALDI-TOF/TOF, and LC-MS/MS. A total of 1920 ESTs from the venom gland cDNA library were sequenced; 74% of them belonged to toxin-families. The four most abundant families among the toxin transcripts were: serine protease (SP, 36.2%), bradykinin potentiating peptide (25.3%), l-amino acid oxidase (LAAO, 13.1%), and phospholipase A2 (PLA2, 9.9%). Moreover, the full sequences of four PLA2s, eight SPs, cysteine-rich secretory protein (CRISP), C-type-lectin-like-protein (CTLP), hyaluronidase, metalloproteinase, and nerve growth factor were deduced from the cDNA sequences. Excluding the CRISP and hyaluronidase, most of the G. intermedius venom proteins bear 92-99% sequence identities to those of other pitviper venoms. The most abundant components are PLA2s (37%), SPs (20%) and LAAO (6%), while metalloproteinase, CTLP, and other components each account for
-
Structures and functions of crotoxin-like heterodimers and acidic phospholipases A2 from Gloydius intermedius venom: Insights into the origin of neurotoxic-type rattlesnakes.
Journal of proteomics, 2014Co-Authors: Zhang-min Yang, Yingming Wang, Zhe-zhi Wang, Qian Guo, Yu Chen, Xu-min Wang, Innho TsaiAbstract:Abstract The cDNAs encoding four major phospholipases A2 (PLA2s) were sequenced while the expressed sequence tags of Gloydius intermedius venom glands were constructed. These PLA2s were designated as Gintexin-A precursor, Gintexin-B, Gin-E6a and Gin-E6b, respectively. The deduced amino acid sequences of the former two PLA2s are 80% and 90% identical to those of crotoxin-A-precursor and crotoxin-B1, respectively. We also purified Gintexin-A, Gintexin-B, Gin-E6a and Gin-E6b like PLA2 from the venom. The latter three PLA2s are enzymatically active but not strongly anticoagulant for human plasma. Gin-E6a and E6b-like PLA2s induced mouse platelet aggregation but inhibited rabbit platelet aggregation. The isolated Gintexin, a 1:1 complex of Gintexin-A and Gintexin-B, blocked the twitch of chick biventer cervicis tissue presynaptically. Results of N-terminal sequencing and peptide mass fingerprinting reveal that Gintexin-A undergoes proteolytic processing similar to crotoxin-A. This is the first time heterodimeric β-neurotoxins are found in Asian pitviper venom, and incompatible neurotoxic- and hemorrhagic-type venoms are found to evolve in parallel within the genus Gloydius, like in Crotalus. Thus, G. intermedius probably is the ancestor of rattlesnakes with type-II venom, and characterization of its venomics helps us to understand the evolution of heterodimeric neurotoxic PLA2s and the paedomorphic trend observed in Neotropical rattlesnake venoms. Biological significance For the first time, a heterodimeric neurotoxic PLA2 (designated as Gintexin) has been isolated from the venom of an Asian pitviper, which shows a characteristic venom gland transcriptome similar to those of the neurotoxic type rattlesnakes. The fact that the venom of G. intermedius is less hemorrhagic than those of other Gloydius species, reveals that incompatible neurotoxic- and hemorrhagic-type venoms have evolved in parallel within the genus Gloydius, like the genus Crotalus. Our findings suggest that G. intermedius is the most probable ancestor of some Neotropical rattlesnakes. The results may revolutionize the theory regarding the origin of type-II rattlesnakes and assist with the diagnosis and clinical management of G. intermedius bites. Furthermore, the possibility of using the currently available antivenoms of Neotropical rattlesnakes to treat G. intermedius bites seems feasible.
-
molecular evolution and structure function relationships of crotoxin like and asparagine 6 containing phospholipases a2 in pit viper venoms
Biochemical Journal, 2004Co-Authors: Yihsuan Chen, Ming-jhy Hseu, Innho Tsai, Yingming WangAbstract:Some myotoxic or neurotoxic PLA2s (phospholipases A2) from pit viper venoms contain characteristic N6 substitutions. Our survey of the venoms of more than ten pit viper genera revealed that N6-PLA2s exist only in limited Asian pit vipers of two genera, Protobothrops and Gloydius, and exist as either monomers or the basic subunits of heterodimers in some New World pit vipers. For the newly identified N6-PLA2s, the neuromuscular blocking activities were assayed with the chick biventer cervicis neuromuscular tissue, whereas the increased serum creatine kinase level assessed their myotoxicities. The purified N6-PLA2s from Protobothrops mangshanensis and Gloydius intermedius saxatilis were found to be presynaptic neurotoxins. In contrast, all N6-PLA2s from the venoms of Sistrurus miliarius strackeri, S. m. barbouri, Crotalus viridis viridis, C. lepidus lepidus, Cerrophidion godmani and Bothreichis schlegelii were myotoxins without neurotoxicity even in the presence of crotoxin A. Crotoxin-like complexes were for the first time purified from the venoms of Sitrurus catenatus tergeminus, C. mitchelli mitchelli, C. horridus atricaudatus, C. basiliscus and C. durissus cumanensis. The cDNAs encoding six novel N6-PLA2s and subunits of the crotoxin-like complex from S. c. tergeminus were cloned and fully sequenced. Phylogeny analysis showed that two structural subtypes of N6-PLA2s with either F24 or S24 substitution have been evolved in parallel, possibly descended respectively from species related to present-day Protobothrops and Gloydius. Calmodulin binds all the N6-PLA2s but crotoxin A may inhibit its binding to crotoxin B and to other neurotoxic N6-PLA2s. Structure–activity relationships at various regions of the PLA2 molecules were extensively discussed.
Mark Fitzgerald - One of the best experts on this subject based on the ideXlab platform.
-
A radiotelemetric study of movements and thermal biology of insular Chinese pit-vipers (Gloydius shedaoensis, Viperidae)
Oikos, 2003Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Because of their low metabolic costs, ectothermic predators can specialise on prey resources that are available for only a brief period each year. Endemic pit-vipers (Gloydius shedaoensis) on a small island in north-eastern China offer an extreme example of this phenomenon, with adult snakes feeding only on seasonally migrating birds that are available for a few weeks in spring and autumn. We surgically implanted radiotransmitters in 16 pit-vipers, and located the snakes at weekly intervals for the next 12 months to record activity, movements, home ranges, habitat use, body temperatures and associated environmental temperatures. The snakes were extremely sedentary, with daily displacements averaging
-
Antipredator Responses of Free-Ranging Pit Vipers(Gloydius shedaoensis, Viperidae)
Copeia, 2002Co-Authors: Richard Shine, Mark Fitzgerald, Michael R. KearneyAbstract:Abstract Few quantitative data are available on the ways in which venomous snakes respond to humans. We took advantage of extraordinarily high numbers of endemic pit vipers on the small island of Shedao in northeastern China, to quantify snake responses. We approached free-ranging pit vipers in their ambush sites (either in trees or on the ground) and recorded their behavior. The snakes' responses to our approach depended upon (1) the intensity of the stimulus; (2) attributes of the snake (size class, body temperature, whether it had fed recently); and (3) the snake's location (in an arboreal or terrestrial site). Most snakes tolerated close approach. Juvenile pit vipers struck more often than adults, and warmer snakes were more likely to flee, display, or strike rather than rely on crypsis. Snakes on the ground were more likely to flee or strike than were those in trees. Many of the same patterns were seen in our laboratory trials. For example, striking was more frequent in juveniles than adults, in hott...
-
Accidental altruism in insular pit-vipers (Gloydius shedaoensis, Viperidae)
Evolutionary Ecology, 2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds' carcasses. Second, large snakes kill raptorial birds (spar- rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this 'accidental altruism' may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao.
-
Research article Accidental altruism in insular pit-vipers (Gloydius
2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael KearneyAbstract:Abstract. Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds ’ carcasses. Second, large snakes kill raptorial birds (spar-rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this ‘accidental altruism ’ may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao
Lixin Sun - One of the best experts on this subject based on the ideXlab platform.
-
The complete mitochondrial genome sequence of Gloydius shedaoensis (Squamata: Viperidae)
Mitochondrial DNA. Part A DNA mapping sequencing and analysis, 2015Co-Authors: Qin Liu, Xiaoping Wang, Fei Zhu, Rong Xiao, Min Fang, Lixin Sun, Peng GuoAbstract:Gloydius shedaoensis is an insular and vulnerable pitviper that is endemic to Snake Island, northeastern China. In this study, we successfully sequenced mitochondrial genomes of two individuals of G. shedaoensis. The complete mitochondrial genomes of G. shedaoensis are circular molecular with 17 222 and 17 221 bp in length respectively, which both contain 2 ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, an origin of light-strand replication (OL) and two non-coding control regions. Compared with previously published mitochondrial genomes of Gloydius species, the base composition and gene arrangement are rather conservative. A Bayesian phylogenetic tree using the complete mitochondrial genomes of all viper species available showed a consistent result with previous studies.
-
A radiotelemetric study of movements and thermal biology of insular Chinese pit-vipers (Gloydius shedaoensis, Viperidae)
Oikos, 2003Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Because of their low metabolic costs, ectothermic predators can specialise on prey resources that are available for only a brief period each year. Endemic pit-vipers (Gloydius shedaoensis) on a small island in north-eastern China offer an extreme example of this phenomenon, with adult snakes feeding only on seasonally migrating birds that are available for a few weeks in spring and autumn. We surgically implanted radiotransmitters in 16 pit-vipers, and located the snakes at weekly intervals for the next 12 months to record activity, movements, home ranges, habitat use, body temperatures and associated environmental temperatures. The snakes were extremely sedentary, with daily displacements averaging
-
Accidental altruism in insular pit-vipers (Gloydius shedaoensis, Viperidae)
Evolutionary Ecology, 2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael R. KearneyAbstract:Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds' carcasses. Second, large snakes kill raptorial birds (spar- rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this 'accidental altruism' may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao.
-
Research article Accidental altruism in insular pit-vipers (Gloydius
2002Co-Authors: Richard Shine, Lixin Sun, Mark Fitzgerald, Michael KearneyAbstract:Abstract. Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds ’ carcasses. Second, large snakes kill raptorial birds (spar-rowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this ‘accidental altruism ’ may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao