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Jeanne E. Young - One of the best experts on this subject based on the ideXlab platform.
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twice every second year reproduction in the pig nosed turtle carettochelys insculpta in the wet Dry Tropics of australia
Journal of Zoology, 2003Co-Authors: Sean J Doody, Arthur Georges, Jeanne E. YoungAbstract:The reproductive biology of female pig-nosed turtles Carettochelys insculpta was studied for 4 years in the wet– Dry Tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the Dry season diet (aquatic vegetation). Life-history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with ‘big’ and ‘small’ wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life-history theory suggest that a big wet season is a time of high energy accumulation for the turtles.
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Twice every second year: reproduction in the pig‐nosed turtle, Carettochelys insculpta, in the wet–Dry Tropics of Australia
Journal of Zoology, 2003Co-Authors: J. S. Doody, Arthur Georges, Jeanne E. YoungAbstract:The reproductive biology of female pig-nosed turtles Carettochelys insculpta was studied for 4 years in the wet– Dry Tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the Dry season diet (aquatic vegetation). Life-history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with ‘big’ and ‘small’ wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life-history theory suggest that a big wet season is a time of high energy accumulation for the turtles.
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Sex Differences in Activity and Movements in the Pig-Nosed Turtle, Carettochelys insculpta, in the Wet-Dry Tropics of Australia
Copeia, 2002Co-Authors: J. S. Doody, Jeanne E. Young, Arthur GeorgesAbstract:Abstract Dry season movement patterns, home ranges, and activity was studied in a population of pig-nosed turtles (Carettochelys insculpta) in the wet-Dry Tropics of northern Australia. Compared to other turtles inhabiting lotic habitats, C. insculpta occupied considerably larger home ranges, covering up to 10 km of river. Of previously published factors influencing home range size, low productivity of the (micro) habitat may best explain the extensive home ranges in C. insculpta. Patchiness and low nutrient value of the chief food (aquatic vegetation) of C. insculpta may force turtles to cover large expanses of river to acquire sufficient energy for growth and reproduction. Females were more active, moved farther, and occupied larger home ranges than males. Home ranges of females comprised 1–4 activity centers, many of which were associated with thermal springs. We suggest that females may exhibit increased activity and movements relative to males because of sexual inequality in parental investment, wher...
Richard Shine - One of the best experts on this subject based on the ideXlab platform.
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Dehydration enhances innate immunity in a semiaquatic snake from the wet-Dry Tropics
Journal of experimental zoology. Part A Ecological and integrative physiology, 2019Co-Authors: George A. Brusch, Keith A. Christian, Gregory P. Brown, Richard Shine, Dale F. DenardoAbstract:Dehydration is considered a physiological challenge, and many organisms live in environments that undergo periods of reduced water availability that can lead to dehydration. Recent studies have found a positive relationship between dehydration and innate immune function in animals adapted to xeric or semixeric environments. To explore the generality of this relationship, we examined the impact of dehydration on innate immune performance in water pythons (Liasis fuscus), a semiaquatic snake from the wet-Dry Tropics of Australia. We collected blood samples from male and female water pythons held in the laboratory without food and water for 4 weeks. We also collected blood from free-ranging snakes throughout the Austral Dry-season. We evaluated plasma osmolality and innate immune function (agglutination, lysis, and bacterial-killing ability) and found that increased osmolality, whether manipulated in the laboratory or as a result of natural water limitation, resulted in enhanced aspects of innate immune performance. Counter-intuitively, snakes in the wild became more hydrated as the Dry season progressed, suggesting the dehydrated snakes move to water sources periodically to rehydrate. Comparing our data with those from previous studies, we suspect species divergence in the level of dehydration (i.e., hyperosmolality) that triggers enhanced immune capabilities.
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activity patterns and movements of free ranging bluetongue lizards tiliqua scincoides intermedia and tiliqua multifasciata in the australian wet Dry Tropics
Journal of Herpetology, 2014Co-Authors: Samantha J Pricerees, Gregory P. Brown, Richard ShineAbstract:Abstract We used GPS-based radiotelemetry to quantify diel activity patterns and movements by two species of large scincid lizards in the Australian wet-Dry Tropics. From an average of 63 days tracking of 54 Northern Bluetongues (Tiliqua scincoides intermedia) and 42 days tracking of 8 Centralian Bluetongues (Tiliqua multifasciata), we obtained 53,801 and 8,139 data points, respectively, on lizard locations over a 13-month period. Lizard species, sex, and study site had relatively little effect on distances moved, at both daily and hourly levels. However, Northern Bluetongues moved further per day than did Centralian Bluetongues at a site where they were sympatric. Most movements were <20 m, with longer movements (dispersal between core areas within the wider home range) occurring primarily during midmorning and late afternoon. The only major effect of ambient temperatures on lizard activity patterns likely was that midday movements were precluded by the risk of overheating; at all other times of the day ...
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Activity Patterns and Movements of Free-Ranging Bluetongue Lizards (Tiliqua scincoides intermedia and Tiliqua multifasciata) in the Australian Wet-Dry Tropics
Journal of Herpetology, 2014Co-Authors: Samantha J. Price-rees, Gregory P. Brown, Richard ShineAbstract:Abstract We used GPS-based radiotelemetry to quantify diel activity patterns and movements by two species of large scincid lizards in the Australian wet-Dry Tropics. From an average of 63 days tracking of 54 Northern Bluetongues (Tiliqua scincoides intermedia) and 42 days tracking of 8 Centralian Bluetongues (Tiliqua multifasciata), we obtained 53,801 and 8,139 data points, respectively, on lizard locations over a 13-month period. Lizard species, sex, and study site had relatively little effect on distances moved, at both daily and hourly levels. However, Northern Bluetongues moved further per day than did Centralian Bluetongues at a site where they were sympatric. Most movements were
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Spatial ecology of bluetongue lizards (Tiliqua spp.) in the Australian wet-Dry Tropics
Austral Ecology, 2012Co-Authors: Samantha J. Price-rees, Gregory P. Brown, Richard ShineAbstract:New technologies for quantifying animal locations enable us to document habitat-selection patterns of cryptic taxa in extraordinary detail. Northern bluetongues (Tiliqua scincoides intermedia) and centralian bluetongues (Tiliqua multifasciata) are large heavy-bodied scincid lizards that are broadly sympatric in the wet–Dry Tropics of north-western Australia. We used data from GPS-based radiotelemetry (n = 49 lizards, tracked for 2–121 days, total n = 61 640 locations) to examine the size, internal structure and overlap of lizard home ranges. Despite substantial habitat differences at our two study sites (semi-arid and relatively pristine habitat at Keep River National Park, Northern Territory, vs. highly disturbed and fragmented flood plain habitat in an agricultural area near Kununurra, Western Australia), home ranges were similar between the two areas, and between the two species. Our radio-tracked lizards continued to disperse into previously unused areas throughout the duration of the study, so that the total areas used by lizards continued to increase. Based on the minimum convex polygon method, total home ranges averaged 4 ha (range 2–12 ha), but only about two-thirds of each home range was used intensively. Each home range had multiple core areas, and overlap of core as well as peripheral areas (especially with same-sex conspecifics) was high at the disturbed (Western Australia) site where lizard densities were high. The concentration of lizard activity within small core areas, often used by multiple individuals, suggests that these heavily used sites are critical to lizard conservation. However, the lizards' infrequent long-distance displacements also make them vulnerable to changes in the wider landscape mosaic. Because GPS-based radiotelemetry can quantify habitat use at finer spatial and temporal scales than earlier technologies, it can provide a robust base for management of at-risk fauna.
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effects of seasonal aridity on the ecology and behaviour of invasive cane toads in the australian wet Dry Tropics
Functional Ecology, 2011Co-Authors: Gregory P. Brown, Crystal Kelehear, Richard ShineAbstract:Summary 1. Measuring the costs imposed by specific environmental challenges is difficult, because organisms adapt in ways that reduce those costs. Invasive species provide an opportunity to quantify environmental impacts before organisms can make adaptive changes. 2. The native range of cane toads (Rhinella marina) lies within the wet neoTropics; although part of this range experiences seasonal drought, many of the places recently invaded by this large anuran species are much more arid. 3. Five years’ fieldwork from a seasonally arid site in the Australian wet–Dry Tropics shows strong seasonal shifts in the toads’ (i) population structure, reflecting seasonality in breeding and recruitment; (ii) adult morphology (secondary sexual characteristics in males); (iii) growth rates; (iv) energy balance; (v) spatial ecology (philopatry, dispersal rates) and (vi) adult mortality rates. 4. Some of these patterns accord with intuition: for example, wet-season conditions resulted in higher rates of growth, reproduction and movement, better body condition and more pronounced secondary sexual characteristics. However, seasonal patterns for other traits were non-intuitive: for example, neither hematocrit levels (reflecting hydration state) nor corticosterone levels (reflecting stress) showed significant seasonal variation, and mortality rates were higher in the wet season than the Dry season. 5. The toads’ ability to flexibly adjust their behaviour and ecology to local hydric conditions has allowed them to thrive even under climatic conditions that preclude activity, feeding and reproduction for most of the year.
Gregory P. Brown - One of the best experts on this subject based on the ideXlab platform.
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Dehydration enhances innate immunity in a semiaquatic snake from the wet-Dry Tropics
Journal of experimental zoology. Part A Ecological and integrative physiology, 2019Co-Authors: George A. Brusch, Keith A. Christian, Gregory P. Brown, Richard Shine, Dale F. DenardoAbstract:Dehydration is considered a physiological challenge, and many organisms live in environments that undergo periods of reduced water availability that can lead to dehydration. Recent studies have found a positive relationship between dehydration and innate immune function in animals adapted to xeric or semixeric environments. To explore the generality of this relationship, we examined the impact of dehydration on innate immune performance in water pythons (Liasis fuscus), a semiaquatic snake from the wet-Dry Tropics of Australia. We collected blood samples from male and female water pythons held in the laboratory without food and water for 4 weeks. We also collected blood from free-ranging snakes throughout the Austral Dry-season. We evaluated plasma osmolality and innate immune function (agglutination, lysis, and bacterial-killing ability) and found that increased osmolality, whether manipulated in the laboratory or as a result of natural water limitation, resulted in enhanced aspects of innate immune performance. Counter-intuitively, snakes in the wild became more hydrated as the Dry season progressed, suggesting the dehydrated snakes move to water sources periodically to rehydrate. Comparing our data with those from previous studies, we suspect species divergence in the level of dehydration (i.e., hyperosmolality) that triggers enhanced immune capabilities.
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activity patterns and movements of free ranging bluetongue lizards tiliqua scincoides intermedia and tiliqua multifasciata in the australian wet Dry Tropics
Journal of Herpetology, 2014Co-Authors: Samantha J Pricerees, Gregory P. Brown, Richard ShineAbstract:Abstract We used GPS-based radiotelemetry to quantify diel activity patterns and movements by two species of large scincid lizards in the Australian wet-Dry Tropics. From an average of 63 days tracking of 54 Northern Bluetongues (Tiliqua scincoides intermedia) and 42 days tracking of 8 Centralian Bluetongues (Tiliqua multifasciata), we obtained 53,801 and 8,139 data points, respectively, on lizard locations over a 13-month period. Lizard species, sex, and study site had relatively little effect on distances moved, at both daily and hourly levels. However, Northern Bluetongues moved further per day than did Centralian Bluetongues at a site where they were sympatric. Most movements were <20 m, with longer movements (dispersal between core areas within the wider home range) occurring primarily during midmorning and late afternoon. The only major effect of ambient temperatures on lizard activity patterns likely was that midday movements were precluded by the risk of overheating; at all other times of the day ...
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Activity Patterns and Movements of Free-Ranging Bluetongue Lizards (Tiliqua scincoides intermedia and Tiliqua multifasciata) in the Australian Wet-Dry Tropics
Journal of Herpetology, 2014Co-Authors: Samantha J. Price-rees, Gregory P. Brown, Richard ShineAbstract:Abstract We used GPS-based radiotelemetry to quantify diel activity patterns and movements by two species of large scincid lizards in the Australian wet-Dry Tropics. From an average of 63 days tracking of 54 Northern Bluetongues (Tiliqua scincoides intermedia) and 42 days tracking of 8 Centralian Bluetongues (Tiliqua multifasciata), we obtained 53,801 and 8,139 data points, respectively, on lizard locations over a 13-month period. Lizard species, sex, and study site had relatively little effect on distances moved, at both daily and hourly levels. However, Northern Bluetongues moved further per day than did Centralian Bluetongues at a site where they were sympatric. Most movements were
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Spatial ecology of bluetongue lizards (Tiliqua spp.) in the Australian wet-Dry Tropics
Austral Ecology, 2012Co-Authors: Samantha J. Price-rees, Gregory P. Brown, Richard ShineAbstract:New technologies for quantifying animal locations enable us to document habitat-selection patterns of cryptic taxa in extraordinary detail. Northern bluetongues (Tiliqua scincoides intermedia) and centralian bluetongues (Tiliqua multifasciata) are large heavy-bodied scincid lizards that are broadly sympatric in the wet–Dry Tropics of north-western Australia. We used data from GPS-based radiotelemetry (n = 49 lizards, tracked for 2–121 days, total n = 61 640 locations) to examine the size, internal structure and overlap of lizard home ranges. Despite substantial habitat differences at our two study sites (semi-arid and relatively pristine habitat at Keep River National Park, Northern Territory, vs. highly disturbed and fragmented flood plain habitat in an agricultural area near Kununurra, Western Australia), home ranges were similar between the two areas, and between the two species. Our radio-tracked lizards continued to disperse into previously unused areas throughout the duration of the study, so that the total areas used by lizards continued to increase. Based on the minimum convex polygon method, total home ranges averaged 4 ha (range 2–12 ha), but only about two-thirds of each home range was used intensively. Each home range had multiple core areas, and overlap of core as well as peripheral areas (especially with same-sex conspecifics) was high at the disturbed (Western Australia) site where lizard densities were high. The concentration of lizard activity within small core areas, often used by multiple individuals, suggests that these heavily used sites are critical to lizard conservation. However, the lizards' infrequent long-distance displacements also make them vulnerable to changes in the wider landscape mosaic. Because GPS-based radiotelemetry can quantify habitat use at finer spatial and temporal scales than earlier technologies, it can provide a robust base for management of at-risk fauna.
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effects of seasonal aridity on the ecology and behaviour of invasive cane toads in the australian wet Dry Tropics
Functional Ecology, 2011Co-Authors: Gregory P. Brown, Crystal Kelehear, Richard ShineAbstract:Summary 1. Measuring the costs imposed by specific environmental challenges is difficult, because organisms adapt in ways that reduce those costs. Invasive species provide an opportunity to quantify environmental impacts before organisms can make adaptive changes. 2. The native range of cane toads (Rhinella marina) lies within the wet neoTropics; although part of this range experiences seasonal drought, many of the places recently invaded by this large anuran species are much more arid. 3. Five years’ fieldwork from a seasonally arid site in the Australian wet–Dry Tropics shows strong seasonal shifts in the toads’ (i) population structure, reflecting seasonality in breeding and recruitment; (ii) adult morphology (secondary sexual characteristics in males); (iii) growth rates; (iv) energy balance; (v) spatial ecology (philopatry, dispersal rates) and (vi) adult mortality rates. 4. Some of these patterns accord with intuition: for example, wet-season conditions resulted in higher rates of growth, reproduction and movement, better body condition and more pronounced secondary sexual characteristics. However, seasonal patterns for other traits were non-intuitive: for example, neither hematocrit levels (reflecting hydration state) nor corticosterone levels (reflecting stress) showed significant seasonal variation, and mortality rates were higher in the wet season than the Dry season. 5. The toads’ ability to flexibly adjust their behaviour and ecology to local hydric conditions has allowed them to thrive even under climatic conditions that preclude activity, feeding and reproduction for most of the year.
Belinda J. Robson - One of the best experts on this subject based on the ideXlab platform.
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do active dispersing insects dominate the invertebrate fauna of rock pools in the wet Dry Tropics kimberley australia
Aquatic Conservation-marine and Freshwater Ecosystems, 2019Co-Authors: Nicole Carey, Adam T. Cross, Matthew D. Barrett, Belinda J. RobsonAbstract:1. Invertebrate assemblages of tropical freshwater rock pools (FRPs) are poorly known compared with temperate regions, where FRPs contain specialized, endemic taxa of high conservation value. Invertebrates were sampled from pristine FRPs in the Morgan River catchment in the Australian wet-Dry Tropics in the 2015 and 2016 wet seasons. Taxa were classified as either active or passive dispersers and by functional feeding groups. A range of physical variables were examined to identify associations with invertebrate assemblages. 2. Forty-seven taxa were identified from FRPs; most were actively dispersing predatory insects, primarily Coleoptera and Hemiptera. Five adult insect species were found in most pools; other taxa were rare and scattered across FRPs. Two previously undescribed species of Spinicaudata were collected, but few crustacean taxa were recorded, and passively dispersing taxa were rare. Species accumulation curves indicated that had more pools been sampled, more taxa would have been collected in 2015, but in 2016 most species were collected. 3. There was no pattern in FRP assemblages related to any physical variable, but the assemblages in pools were correlated between sampling times. An opportunistic and mobile assemblage composed mostly of actively dispersing predatory insects may explain the absence of relationships with measured variables. Low hydrological stability in the wet-Dry Tropics may be associated with low taxon richness. 4. The dominance of actively dispersing insects is in contrast with FRP assemblages in temperate and arid regions. Studies of a wider range of FRPs from tropical regions are required to determine whether the fauna of these Kimberley FRPs are typical, and to fully describe short-range endemic species across the Kimberley and elsewhere. 5. The FRPs have conservation value as habitat for endemic, specialist rock-pool taxa, contributing to regional species pools. At present, a lack of knowledge of endemic FRP specialist species in tropical regions, including the Kimberley, impedes our ability to protect and conserve these species from disturbance.
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Do active-dispersing insects dominate the invertebrate fauna of rock pools in the wet–Dry Tropics, Kimberley, Australia?
Aquatic Conservation: Marine and Freshwater Ecosystems, 2019Co-Authors: Nicole Carey, Adam T. Cross, Matthew D. Barrett, Belinda J. RobsonAbstract:1. Invertebrate assemblages of tropical freshwater rock pools (FRPs) are poorly known compared with temperate regions, where FRPs contain specialized, endemic taxa of high conservation value. Invertebrates were sampled from pristine FRPs in the Morgan River catchment in the Australian wet-Dry Tropics in the 2015 and 2016 wet seasons. Taxa were classified as either active or passive dispersers and by functional feeding groups. A range of physical variables were examined to identify associations with invertebrate assemblages. 2. Forty-seven taxa were identified from FRPs; most were actively dispersing predatory insects, primarily Coleoptera and Hemiptera. Five adult insect species were found in most pools; other taxa were rare and scattered across FRPs. Two previously undescribed species of Spinicaudata were collected, but few crustacean taxa were recorded, and passively dispersing taxa were rare. Species accumulation curves indicated that had more pools been sampled, more taxa would have been collected in 2015, but in 2016 most species were collected. 3. There was no pattern in FRP assemblages related to any physical variable, but the assemblages in pools were correlated between sampling times. An opportunistic and mobile assemblage composed mostly of actively dispersing predatory insects may explain the absence of relationships with measured variables. Low hydrological stability in the wet-Dry Tropics may be associated with low taxon richness. 4. The dominance of actively dispersing insects is in contrast with FRP assemblages in temperate and arid regions. Studies of a wider range of FRPs from tropical regions are required to determine whether the fauna of these Kimberley FRPs are typical, and to fully describe short-range endemic species across the Kimberley and elsewhere. 5. The FRPs have conservation value as habitat for endemic, specialist rock-pool taxa, contributing to regional species pools. At present, a lack of knowledge of endemic FRP specialist species in tropical regions, including the Kimberley, impedes our ability to protect and conserve these species from disturbance.
Arthur Georges - One of the best experts on this subject based on the ideXlab platform.
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twice every second year reproduction in the pig nosed turtle carettochelys insculpta in the wet Dry Tropics of australia
Journal of Zoology, 2003Co-Authors: Sean J Doody, Arthur Georges, Jeanne E. YoungAbstract:The reproductive biology of female pig-nosed turtles Carettochelys insculpta was studied for 4 years in the wet– Dry Tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the Dry season diet (aquatic vegetation). Life-history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with ‘big’ and ‘small’ wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life-history theory suggest that a big wet season is a time of high energy accumulation for the turtles.
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Twice every second year: reproduction in the pig‐nosed turtle, Carettochelys insculpta, in the wet–Dry Tropics of Australia
Journal of Zoology, 2003Co-Authors: J. S. Doody, Arthur Georges, Jeanne E. YoungAbstract:The reproductive biology of female pig-nosed turtles Carettochelys insculpta was studied for 4 years in the wet– Dry Tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the Dry season diet (aquatic vegetation). Life-history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with ‘big’ and ‘small’ wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life-history theory suggest that a big wet season is a time of high energy accumulation for the turtles.
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Sex Differences in Activity and Movements in the Pig-Nosed Turtle, Carettochelys insculpta, in the Wet-Dry Tropics of Australia
Copeia, 2002Co-Authors: J. S. Doody, Jeanne E. Young, Arthur GeorgesAbstract:Abstract Dry season movement patterns, home ranges, and activity was studied in a population of pig-nosed turtles (Carettochelys insculpta) in the wet-Dry Tropics of northern Australia. Compared to other turtles inhabiting lotic habitats, C. insculpta occupied considerably larger home ranges, covering up to 10 km of river. Of previously published factors influencing home range size, low productivity of the (micro) habitat may best explain the extensive home ranges in C. insculpta. Patchiness and low nutrient value of the chief food (aquatic vegetation) of C. insculpta may force turtles to cover large expanses of river to acquire sufficient energy for growth and reproduction. Females were more active, moved farther, and occupied larger home ranges than males. Home ranges of females comprised 1–4 activity centers, many of which were associated with thermal springs. We suggest that females may exhibit increased activity and movements relative to males because of sexual inequality in parental investment, wher...
