The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
Christine L. Huffard - One of the best experts on this subject based on the ideXlab platform.
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Nocturnal mating behaviour and dynamic male investment of copulation time in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Behaviour, 2020Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosaHoyle (1883), is a nocturnal species that exhibits a mating system in which females hold sperm from multiple males over a one to two month breeding window before laying a single egg clutch. Contrary to most studied animal mating systems where anisogamy exists, gamete package production is limited for both males and females of this species (approx. 50 spermatophores/eggs). This presents an animal model for studying aspects of sperm competition and dynamic mate choice behaviours. The present study reports on the mating behaviour of H. maculosaobserved under laboratory conditions using infrared closed-circuit television video footage. Rates of male copulation attempts increased with male size, while female receptivity to mating attempts increased with female size, resulting in larger animals of both sexes gaining more copulations and spending more time per day in copulation. There was some evidence of female preference of larger males, but no male preference of females based on measured morphological traits. Both sexes terminated copulations in equal frequencies but male-terminated copulations were significantly shorter in duration. Males were more likely to terminate copulation early with females they had previously mated with, however were less likely to do so if the female had recently mated with a different male. Among male-terminated copulations, males mated for longer with females that had previously mated with other males in the trial. Male–male mounts were as common as male–female mounts, suggesting that male H. maculosaare not able to discriminate the sex of conspecifics. These findings suggest male strategic allocation of spermatophores based female mating history is an important factor influencing mating behaviours of this species.
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Mating behaviour and postcopulatory fertilization patterns in the southern Blue-Ringed Octopus, Hapalochlaena maculosa
Animal Behaviour, 2018Co-Authors: Peter Morse, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Kyall R. ZengerAbstract:Female Octopuses are known to store sperm from multiple males they encounter throughout a breeding season, before laying a single clutch with mixed paternity. Although Octopuses display a broad range of precopulatory behaviours, and both sperm competition and cryptic female choice have been hypothesized to occur, the current understanding of how these processes influence resulting paternity remains limited. This study aimed to identify behavioural factors associated with paternity patterns and the capacity of females to bias paternity postcopulation to specific males in the southern Blue-Ringed Octopus, Hapalochlaena maculosa. Genetic markers and controlled, sequential, laboratory pairings of genotyped individuals were used to examine paternity patterns and compare them to relative signatures of male sperm remaining in female oviducal glands after egg laying. Multiple paternity was discovered in all 12 laboratory-reared clutches. There was no indication that the relative time spent in copulation affected the resulting paternity. Males that waited for females to terminate the copulation had greater paternity when they were the first candidate male, but this was not the case among second candidate males. The relative quantities of candidate male alleles detected in female oviducal glands after egg laying were consistent with relative paternity of the candidate males in all but three cases. In one of these, sibship analysis revealed that the male that obtained less paternity than expected was in fact the female's full-sibling brother. Although this study found no evidence for female postcopulatory selection of male sperm, anecdotal evidence suggests that female H. maculosa might benefit from polyandry if chemical processes can favour clutch fertilization by unrelated males. Future studies, investigating paternity bias among genotyped males of varying, but known relatedness to the female, might help to validate this pattern.
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Genome-wide comparisons reveal a clinal species pattern within a holobenthic octopod - the Australian Southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Ecology and Evolution, 2018Co-Authors: Peter Morse, Julian Finn, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Shannon R. Kjeldsen, Kyall R. ZengerAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) lacks a planktonic dispersal phase, yet ranges across Australia’s southern coastline. This species’ brief and holobenthic life history suggests gene flow might be limited, leaving distant populations prone to strong genetic divergence. This study used 17,523 genome-wide SNP loci to investigate genetic structuring and local adaptation patterns of H. maculosa among eight sampling sites along its reported range. Within sites, interrelatedness was very high, consistent with the limited dispersal of this taxon. However, inbreeding coefficients were proportionally lower among sites where substructuring was not detected, suggesting H. maculosa might possess a mechanism for inbreeding avoidance. Genetic divergence was extremely high among all sites, with the greatest divergence observed between both ends of the distribution, Fremantle, WA, and Stanley, TAS. Genetic distances closely followed an isolation by geographic distance pattern. Outlier analyses revealed distinct selection signatures at all sites, with the strongest divergence reported between Fremantle and the other Western Australian sites. Phylogenetic reconstructions using the described sister taxon H. fasciata (Hoyle, 1886) further supported that the genetic divergence between distal H. maculosa sites in this study was equivalent to that of between established heterospecifics within this genus. However, it is advocated that taxonomic delineations within this species should be made with caution. These data indicate that H. maculosa forms a clinal species pattern across its geographic range, with gene flow present through allele sharing between adjacent populations. Morphological investigations are recommended for a robust resolution of the taxonomic identity and ecotype boundaries of this species
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Chemical cues correlate with agonistic behaviour and female mate choice in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) (Cephalopoda: Octopodidae)
Journal of Molluscan Studies, 2016Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:Chemoreception cues potentially influence intraspecific interactions of cephalopods, including mate choice. However, at present there is limited empirical evidence demonstrating whether cephalopods can use olfaction to identify the sex or identity of conspecifics. This study examined the responses of the southern blueringed Octopus, Hapalochlaena maculosa (Hoyle, 1883), to conspecific odours during controlled laboratory trials. The ventilation rates in aquaria of 25 wild-sourced animals were measured during four treatments: baseline, sea water, sea water containing male conspecific odour and sea water containing female conspecific odour. When used as 'receivers' in trials, female H. maculosa significantly increased their ventilation rates in response to male odours, but not to female odours. However, female response decreased significantly with the receiver's size during female-odour treatments. The ventilation rates of male H. maculosa were statistically similar in all treatments. However, their ventilation rates showed a significant progressive increase over the observation period during male and female-odour treatments. Eighteen of these animals (nine females and nine males) were used in focal-animal trials 1 week after odour-cue experiments. Of these individuals, females were significantly more receptive to copulation attempts, and spent significantly more time per day in copulation, with males whose odours had elicited a weaker ventilation response in prior trials. These results suggest that female H. maculosa can use chemosensory cues to discriminate the sex, and possibly identity, of conspecifics and that this information might influence their mate choice. However, the mechanisms underlying these responses and subsequent copulatory access to females by males remain unknown.
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Chemical defense in pelagic Octopus paralarvae: Tetrodotoxin alone does not protect individual paralarvae of the greater Blue-Ringed Octopus (Hapalochlaena lunulata) from common reef predators
Chemoecology, 2011Co-Authors: Becky L. Williams, Christine L. Huffard, Vanessa Lovenburg, Roy L. CaldwellAbstract:Some pelagic marine larvae possess anti-predator chemical defenses. Occasionally, toxic adults imbue their young with their own defensive cocktails. We examined paralarvae of the greater Blue-Ringed Octopus ( Hapalochlaena lunulata ) for the deadly neurotoxin tetrodotoxin (TTX), and if present, whether TTX conferred protection to individual paralarvae. Paralarvae of H. lunulata possessed 150 ± 17 ng TTX each. These paralarvae appeared distasteful to a variety of fish and stomatopod predators, yet food items spiked with 200 ng TTX were readily consumed by predators. We conclude that TTX alone does not confer individual protection to paralarvae of H. lunulata , and that they possess an alternative defense. In larger doses, tetrodotoxin is a deterrent to the predatory stomatopod Haptosquilla trispinosa (mean dose = 3.97 μg/g). This corresponds to 12–13 paralarvae per predator based on the TTX levels of the clutch we examined. Thus, the basic assumption that individual paralarvae of H. lunulata are defended by TTX alone was disproved. Instead, functionality of TTX levels in paralarvae may arise through alternative selective pathways, such as deterrence to parasites, through kin selection, or against predator species not tested here.
Roy L. Caldwell - One of the best experts on this subject based on the ideXlab platform.
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Chemical defense in pelagic Octopus paralarvae: Tetrodotoxin alone does not protect individual paralarvae of the greater Blue-Ringed Octopus (Hapalochlaena lunulata) from common reef predators
Chemoecology, 2011Co-Authors: Becky L. Williams, Christine L. Huffard, Vanessa Lovenburg, Roy L. CaldwellAbstract:Some pelagic marine larvae possess anti-predator chemical defenses. Occasionally, toxic adults imbue their young with their own defensive cocktails. We examined paralarvae of the greater Blue-Ringed Octopus ( Hapalochlaena lunulata ) for the deadly neurotoxin tetrodotoxin (TTX), and if present, whether TTX conferred protection to individual paralarvae. Paralarvae of H. lunulata possessed 150 ± 17 ng TTX each. These paralarvae appeared distasteful to a variety of fish and stomatopod predators, yet food items spiked with 200 ng TTX were readily consumed by predators. We conclude that TTX alone does not confer individual protection to paralarvae of H. lunulata , and that they possess an alternative defense. In larger doses, tetrodotoxin is a deterrent to the predatory stomatopod Haptosquilla trispinosa (mean dose = 3.97 μg/g). This corresponds to 12–13 paralarvae per predator based on the TTX levels of the clutch we examined. Thus, the basic assumption that individual paralarvae of H. lunulata are defended by TTX alone was disproved. Instead, functionality of TTX levels in paralarvae may arise through alternative selective pathways, such as deterrence to parasites, through kin selection, or against predator species not tested here.
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Inking in a Blue-Ringed Octopus, Hapalochlaena lunulata, with a vestigial ink sac
Pacific Science, 2002Co-Authors: Christine L. Huffard, Roy L. CaldwellAbstract:Here we report for the first time that adult Hapalochlaena lunulata (Quoy & Gaimard, 1832), which has a vestigial ink sac, is capable of inking. Ink was released under three different agonistic conditions: female-female aggression, rejection of mating attempt, and when attacked by a predator. We observed no apparent reaction to the ink by the other animals involved in these interactions.
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Sex identification and mating in the Blue-Ringed Octopus, Hapalochlaena lunulata.
Animal Behaviour, 2000Co-Authors: Mary W. Cheng, Roy L. CaldwellAbstract:Abstract We studied the reproductive behaviour of the Blue-Ringed Octopus, Hapalochlaena lunulata, in the laboratory by examining 15 male–male and nine male–female interactions. The initiation of physical contact was independent of sex, size or residency status, and there were no noticeable changes in behaviour such as sexual displays associated with courtship or aggression prior to contact. Males did not distinguish between females or other males and copulated (defined as the insertion of the hectocotylus into the mantle cavity of another Octopus) readily with both. Spermatophores were released in all copulations with females but not with males. The duration of copulation was significantly longer in male–female interactions (median 160.5 min) than in male–male interactions (median 30 s). Although male–male copulations ended passively with the withdrawal of the hectocotylus by the initiating animal, male–female copulations were always terminated by the females following an intense struggle. These studies suggest the inability of male H. lunulata to determine the sexual identity of potential mates prior to the insertion of the hectocotylus and demonstrate the active role of the female during copulation.
Kyall R. Zenger - One of the best experts on this subject based on the ideXlab platform.
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Nocturnal mating behaviour and dynamic male investment of copulation time in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Behaviour, 2020Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosaHoyle (1883), is a nocturnal species that exhibits a mating system in which females hold sperm from multiple males over a one to two month breeding window before laying a single egg clutch. Contrary to most studied animal mating systems where anisogamy exists, gamete package production is limited for both males and females of this species (approx. 50 spermatophores/eggs). This presents an animal model for studying aspects of sperm competition and dynamic mate choice behaviours. The present study reports on the mating behaviour of H. maculosaobserved under laboratory conditions using infrared closed-circuit television video footage. Rates of male copulation attempts increased with male size, while female receptivity to mating attempts increased with female size, resulting in larger animals of both sexes gaining more copulations and spending more time per day in copulation. There was some evidence of female preference of larger males, but no male preference of females based on measured morphological traits. Both sexes terminated copulations in equal frequencies but male-terminated copulations were significantly shorter in duration. Males were more likely to terminate copulation early with females they had previously mated with, however were less likely to do so if the female had recently mated with a different male. Among male-terminated copulations, males mated for longer with females that had previously mated with other males in the trial. Male–male mounts were as common as male–female mounts, suggesting that male H. maculosaare not able to discriminate the sex of conspecifics. These findings suggest male strategic allocation of spermatophores based female mating history is an important factor influencing mating behaviours of this species.
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The evolution and origin of tetrodotoxin acquisition in the Blue-Ringed Octopus (genus Hapalochlaena).
Aquatic Toxicology, 2018Co-Authors: Brooke Whitelaw, Ira R. Cooke, Julian Finn, Kyall R. Zenger, Jan M. StrugnellAbstract:Abstract Tetrodotoxin is a potent non-proteinaceous neurotoxin, which is commonly found in the marine environment. Synthesised by bacteria, tetrodotoxin has been isolated from the tissues of several genera including pufferfish, salamanders and Octopus. Believed to provide a defensive function, the independent evolution of tetrodotoxin sequestration is poorly understood in most species. Two mechanisms of tetrodotoxin resistance have been identified to date, tetrodotoxin binding proteins in the circulatory system and mutations to voltage gated sodium channels, the binding target of tetrodotoxin with the former potentially succeeding the latter in evolutionary time. This review focuses on the evolution of tetrodotoxin acquisition, in particular how it may have occurred within the Blue-Ringed Octopus genus (Hapalochlaena) and the subsequent impact on venom evolution.
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Mating behaviour and postcopulatory fertilization patterns in the southern Blue-Ringed Octopus, Hapalochlaena maculosa
Animal Behaviour, 2018Co-Authors: Peter Morse, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Kyall R. ZengerAbstract:Female Octopuses are known to store sperm from multiple males they encounter throughout a breeding season, before laying a single clutch with mixed paternity. Although Octopuses display a broad range of precopulatory behaviours, and both sperm competition and cryptic female choice have been hypothesized to occur, the current understanding of how these processes influence resulting paternity remains limited. This study aimed to identify behavioural factors associated with paternity patterns and the capacity of females to bias paternity postcopulation to specific males in the southern Blue-Ringed Octopus, Hapalochlaena maculosa. Genetic markers and controlled, sequential, laboratory pairings of genotyped individuals were used to examine paternity patterns and compare them to relative signatures of male sperm remaining in female oviducal glands after egg laying. Multiple paternity was discovered in all 12 laboratory-reared clutches. There was no indication that the relative time spent in copulation affected the resulting paternity. Males that waited for females to terminate the copulation had greater paternity when they were the first candidate male, but this was not the case among second candidate males. The relative quantities of candidate male alleles detected in female oviducal glands after egg laying were consistent with relative paternity of the candidate males in all but three cases. In one of these, sibship analysis revealed that the male that obtained less paternity than expected was in fact the female's full-sibling brother. Although this study found no evidence for female postcopulatory selection of male sperm, anecdotal evidence suggests that female H. maculosa might benefit from polyandry if chemical processes can favour clutch fertilization by unrelated males. Future studies, investigating paternity bias among genotyped males of varying, but known relatedness to the female, might help to validate this pattern.
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Genome-wide comparisons reveal a clinal species pattern within a holobenthic octopod - the Australian Southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Ecology and Evolution, 2018Co-Authors: Peter Morse, Julian Finn, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Shannon R. Kjeldsen, Kyall R. ZengerAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) lacks a planktonic dispersal phase, yet ranges across Australia’s southern coastline. This species’ brief and holobenthic life history suggests gene flow might be limited, leaving distant populations prone to strong genetic divergence. This study used 17,523 genome-wide SNP loci to investigate genetic structuring and local adaptation patterns of H. maculosa among eight sampling sites along its reported range. Within sites, interrelatedness was very high, consistent with the limited dispersal of this taxon. However, inbreeding coefficients were proportionally lower among sites where substructuring was not detected, suggesting H. maculosa might possess a mechanism for inbreeding avoidance. Genetic divergence was extremely high among all sites, with the greatest divergence observed between both ends of the distribution, Fremantle, WA, and Stanley, TAS. Genetic distances closely followed an isolation by geographic distance pattern. Outlier analyses revealed distinct selection signatures at all sites, with the strongest divergence reported between Fremantle and the other Western Australian sites. Phylogenetic reconstructions using the described sister taxon H. fasciata (Hoyle, 1886) further supported that the genetic divergence between distal H. maculosa sites in this study was equivalent to that of between established heterospecifics within this genus. However, it is advocated that taxonomic delineations within this species should be made with caution. These data indicate that H. maculosa forms a clinal species pattern across its geographic range, with gene flow present through allele sharing between adjacent populations. Morphological investigations are recommended for a robust resolution of the taxonomic identity and ecotype boundaries of this species
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Chemical cues correlate with agonistic behaviour and female mate choice in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) (Cephalopoda: Octopodidae)
Journal of Molluscan Studies, 2016Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:Chemoreception cues potentially influence intraspecific interactions of cephalopods, including mate choice. However, at present there is limited empirical evidence demonstrating whether cephalopods can use olfaction to identify the sex or identity of conspecifics. This study examined the responses of the southern blueringed Octopus, Hapalochlaena maculosa (Hoyle, 1883), to conspecific odours during controlled laboratory trials. The ventilation rates in aquaria of 25 wild-sourced animals were measured during four treatments: baseline, sea water, sea water containing male conspecific odour and sea water containing female conspecific odour. When used as 'receivers' in trials, female H. maculosa significantly increased their ventilation rates in response to male odours, but not to female odours. However, female response decreased significantly with the receiver's size during female-odour treatments. The ventilation rates of male H. maculosa were statistically similar in all treatments. However, their ventilation rates showed a significant progressive increase over the observation period during male and female-odour treatments. Eighteen of these animals (nine females and nine males) were used in focal-animal trials 1 week after odour-cue experiments. Of these individuals, females were significantly more receptive to copulation attempts, and spent significantly more time per day in copulation, with males whose odours had elicited a weaker ventilation response in prior trials. These results suggest that female H. maculosa can use chemosensory cues to discriminate the sex, and possibly identity, of conspecifics and that this information might influence their mate choice. However, the mechanisms underlying these responses and subsequent copulatory access to females by males remain unknown.
Peter Morse - One of the best experts on this subject based on the ideXlab platform.
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Nocturnal mating behaviour and dynamic male investment of copulation time in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Behaviour, 2020Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosaHoyle (1883), is a nocturnal species that exhibits a mating system in which females hold sperm from multiple males over a one to two month breeding window before laying a single egg clutch. Contrary to most studied animal mating systems where anisogamy exists, gamete package production is limited for both males and females of this species (approx. 50 spermatophores/eggs). This presents an animal model for studying aspects of sperm competition and dynamic mate choice behaviours. The present study reports on the mating behaviour of H. maculosaobserved under laboratory conditions using infrared closed-circuit television video footage. Rates of male copulation attempts increased with male size, while female receptivity to mating attempts increased with female size, resulting in larger animals of both sexes gaining more copulations and spending more time per day in copulation. There was some evidence of female preference of larger males, but no male preference of females based on measured morphological traits. Both sexes terminated copulations in equal frequencies but male-terminated copulations were significantly shorter in duration. Males were more likely to terminate copulation early with females they had previously mated with, however were less likely to do so if the female had recently mated with a different male. Among male-terminated copulations, males mated for longer with females that had previously mated with other males in the trial. Male–male mounts were as common as male–female mounts, suggesting that male H. maculosaare not able to discriminate the sex of conspecifics. These findings suggest male strategic allocation of spermatophores based female mating history is an important factor influencing mating behaviours of this species.
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Mating behaviour and postcopulatory fertilization patterns in the southern Blue-Ringed Octopus, Hapalochlaena maculosa
Animal Behaviour, 2018Co-Authors: Peter Morse, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Kyall R. ZengerAbstract:Female Octopuses are known to store sperm from multiple males they encounter throughout a breeding season, before laying a single clutch with mixed paternity. Although Octopuses display a broad range of precopulatory behaviours, and both sperm competition and cryptic female choice have been hypothesized to occur, the current understanding of how these processes influence resulting paternity remains limited. This study aimed to identify behavioural factors associated with paternity patterns and the capacity of females to bias paternity postcopulation to specific males in the southern Blue-Ringed Octopus, Hapalochlaena maculosa. Genetic markers and controlled, sequential, laboratory pairings of genotyped individuals were used to examine paternity patterns and compare them to relative signatures of male sperm remaining in female oviducal glands after egg laying. Multiple paternity was discovered in all 12 laboratory-reared clutches. There was no indication that the relative time spent in copulation affected the resulting paternity. Males that waited for females to terminate the copulation had greater paternity when they were the first candidate male, but this was not the case among second candidate males. The relative quantities of candidate male alleles detected in female oviducal glands after egg laying were consistent with relative paternity of the candidate males in all but three cases. In one of these, sibship analysis revealed that the male that obtained less paternity than expected was in fact the female's full-sibling brother. Although this study found no evidence for female postcopulatory selection of male sperm, anecdotal evidence suggests that female H. maculosa might benefit from polyandry if chemical processes can favour clutch fertilization by unrelated males. Future studies, investigating paternity bias among genotyped males of varying, but known relatedness to the female, might help to validate this pattern.
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Genome-wide comparisons reveal a clinal species pattern within a holobenthic octopod - the Australian Southern Blue-Ringed Octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)
Ecology and Evolution, 2018Co-Authors: Peter Morse, Julian Finn, Christine L. Huffard, Mark G. Meekan, Mark I. Mccormick, Shannon R. Kjeldsen, Kyall R. ZengerAbstract:The southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) lacks a planktonic dispersal phase, yet ranges across Australia’s southern coastline. This species’ brief and holobenthic life history suggests gene flow might be limited, leaving distant populations prone to strong genetic divergence. This study used 17,523 genome-wide SNP loci to investigate genetic structuring and local adaptation patterns of H. maculosa among eight sampling sites along its reported range. Within sites, interrelatedness was very high, consistent with the limited dispersal of this taxon. However, inbreeding coefficients were proportionally lower among sites where substructuring was not detected, suggesting H. maculosa might possess a mechanism for inbreeding avoidance. Genetic divergence was extremely high among all sites, with the greatest divergence observed between both ends of the distribution, Fremantle, WA, and Stanley, TAS. Genetic distances closely followed an isolation by geographic distance pattern. Outlier analyses revealed distinct selection signatures at all sites, with the strongest divergence reported between Fremantle and the other Western Australian sites. Phylogenetic reconstructions using the described sister taxon H. fasciata (Hoyle, 1886) further supported that the genetic divergence between distal H. maculosa sites in this study was equivalent to that of between established heterospecifics within this genus. However, it is advocated that taxonomic delineations within this species should be made with caution. These data indicate that H. maculosa forms a clinal species pattern across its geographic range, with gene flow present through allele sharing between adjacent populations. Morphological investigations are recommended for a robust resolution of the taxonomic identity and ecotype boundaries of this species
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Chemical cues correlate with agonistic behaviour and female mate choice in the southern Blue-Ringed Octopus, Hapalochlaena maculosa (Hoyle, 1883) (Cephalopoda: Octopodidae)
Journal of Molluscan Studies, 2016Co-Authors: Peter Morse, Kyall R. Zenger, Mark G. Meekan, Mark I. Mccormick, Christine L. HuffardAbstract:Chemoreception cues potentially influence intraspecific interactions of cephalopods, including mate choice. However, at present there is limited empirical evidence demonstrating whether cephalopods can use olfaction to identify the sex or identity of conspecifics. This study examined the responses of the southern blueringed Octopus, Hapalochlaena maculosa (Hoyle, 1883), to conspecific odours during controlled laboratory trials. The ventilation rates in aquaria of 25 wild-sourced animals were measured during four treatments: baseline, sea water, sea water containing male conspecific odour and sea water containing female conspecific odour. When used as 'receivers' in trials, female H. maculosa significantly increased their ventilation rates in response to male odours, but not to female odours. However, female response decreased significantly with the receiver's size during female-odour treatments. The ventilation rates of male H. maculosa were statistically similar in all treatments. However, their ventilation rates showed a significant progressive increase over the observation period during male and female-odour treatments. Eighteen of these animals (nine females and nine males) were used in focal-animal trials 1 week after odour-cue experiments. Of these individuals, females were significantly more receptive to copulation attempts, and spent significantly more time per day in copulation, with males whose odours had elicited a weaker ventilation response in prior trials. These results suggest that female H. maculosa can use chemosensory cues to discriminate the sex, and possibly identity, of conspecifics and that this information might influence their mate choice. However, the mechanisms underlying these responses and subsequent copulatory access to females by males remain unknown.
Becky L. Williams - One of the best experts on this subject based on the ideXlab platform.
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Convergent and parallel evolution in a voltage-gated sodium channel underlies TTX-resistance in the Greater Blue-Ringed Octopus: Hapalochlaena lunulata.
Toxicon, 2019Co-Authors: Shana L. Geffeney, Becky L. Williams, Joshua J. C. Rosenthal, Matthew A. Birk, Justin Felkins, Christine M. Wisell, Eveningstar R. Curry, Charles T. HanifinAbstract:Abstract The natural history and pharmacology of tetrodotoxin (TTX) has long intrigued biologists. This toxin has a remarkable distribution that spans two domains of life (Bacteria and Eukarya). Within Eukaryotes, TTX has only been identified in animals but is known to be present in over five-dozen species of phylogenetically distant Metazoans. Despite decades of work, the origin and biosynthetic pathways of TTX remain unresolved. Investigations in puffer fishes and salamanders have provided insights into the acquisition of auto-resistance to TTX through the evolution of voltage-gated sodium ion channels (VGSCs) that have reduced binding affinity for TTX. To date there have been no studies of these proteins in tetrodotoxic Blue-Ringed Octopuses. Here we report data demonstrating that the Greater Blue-Ringed Octopus (Hapalochlaena lunulata) expresses a VGSC (HlNaV1) gene with mutations that reduce the channel's TTX-binding affinity and likely render the organism TTX resistant. We identified three amino-acid substitutions in the TTX-binding site of HlNaV1 that likely confer TTX-resistance to both the channel and the organism. These substitutions are associated with organismal TTX-resistance in other TTX-bearing taxa and are convergent with substitutions that have evolved in fish, salamanders, and some TTX-resistant invertebrates.
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Chemical defense in pelagic Octopus paralarvae: Tetrodotoxin alone does not protect individual paralarvae of the greater Blue-Ringed Octopus (Hapalochlaena lunulata) from common reef predators
Chemoecology, 2011Co-Authors: Becky L. Williams, Christine L. Huffard, Vanessa Lovenburg, Roy L. CaldwellAbstract:Some pelagic marine larvae possess anti-predator chemical defenses. Occasionally, toxic adults imbue their young with their own defensive cocktails. We examined paralarvae of the greater Blue-Ringed Octopus ( Hapalochlaena lunulata ) for the deadly neurotoxin tetrodotoxin (TTX), and if present, whether TTX conferred protection to individual paralarvae. Paralarvae of H. lunulata possessed 150 ± 17 ng TTX each. These paralarvae appeared distasteful to a variety of fish and stomatopod predators, yet food items spiked with 200 ng TTX were readily consumed by predators. We conclude that TTX alone does not confer individual protection to paralarvae of H. lunulata , and that they possess an alternative defense. In larger doses, tetrodotoxin is a deterrent to the predatory stomatopod Haptosquilla trispinosa (mean dose = 3.97 μg/g). This corresponds to 12–13 paralarvae per predator based on the TTX levels of the clutch we examined. Thus, the basic assumption that individual paralarvae of H. lunulata are defended by TTX alone was disproved. Instead, functionality of TTX levels in paralarvae may arise through alternative selective pathways, such as deterrence to parasites, through kin selection, or against predator species not tested here.
