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D. M. Stoddart - One of the best experts on this subject based on the ideXlab platform.
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Plasma androgen, social position, and response to GnRH in the marsupial sugar glider Petaurus breviceps (Marsupialia: Petauridae)
Journal of Zoology, 1997Co-Authors: Adrian J. Bradley, D. M. StoddartAbstract:The effect of gonadotrophin-releasing hormone GnRH on plasma testosterone was examined in male sugar gliders Petaurus breviceps that were judged to occupy either the highest or lowest position in stable colonies consisting of up to four males and two females. Experiment were carried out at a time when breeding occurred in two of the three colonies, as evidenced by the presence of pouch young.
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plasma testosterone concentration body weight social dominance and scent marking in male marsupial sugar gliders petaurus breviceps marsupialia Petauridae
Journal of Zoology, 1994Co-Authors: D. M. Stoddart, A J Bradley, J. MallickAbstract:Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live-trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body weight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the heaviest. In captivity this male is observed to be socially the most dominant and undertakes almost all of the scent-marking. At least three-quarters of each breeding season's births occur during the first month of the three- to four-month season (July-September/October), a passage of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits of high social status being immense.
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Behavioral and endocrinological correlates of social status in the male sugar glider (Petaurus breviceps Marsupialia: Petauridae).
Physiology & behavior, 1994Co-Authors: J. Mallick, D. M. Stoddart, Ivor H. Jones, Adrian J. BradleyAbstract:Socially dominant male sugar gliders are heavier than socially subordinate males, have higher plasma testosterone and lower cortisol concentrations, win more social encounters, scan the arena more, scent-mark more, and are more active and move more quickly, even though they spend more time in the colony nesting box. When they are transferred into a foreign stable colony there is an impressive reversal of behavioral measures and a concomitant decrease in concentration of plasma testosterone and rise in cortisol that is apparent over the first 3 weeks of observation.
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The dorsal paracloacal gland and its relationship with seasonal changes in cutaneous scent gland morphology and plasma androgen in the marsupial sugar glider (Petaurus breviceps; Marsupialia: Petauridae)
Journal of Zoology, 1993Co-Authors: Adrian J. Bradley, D. M. StoddartAbstract:A study spanning two breeding seasons was carried out to examine changes in the size of the dorsal paracloacal glands and testes in the marsupial sugar glider Petaurus breviceps Waterhouse 1839. These changes were related to seasonal increases in the plasma testosterone concentration and to morphological changes in the frontal and gular cutaneous scent glands of males. Both dorsal paracloacal glands and testes underwent a seasonal cycle of development which reached its maximum during the June-September breeding season. These changes coincided with an increase in the plasma testosterone concentration and with the increase in activity of certain cell types within the frontal and gular glands. Castration caused a significant decrease in the size of the dorsal paracloacal glands, while androgen replacement was effective in restoring the glands to their pre-castration size thus demonstrating the influence of androgens upon the activity of these glands. The synchronization which exists between plasma testosterone concentration, cutaneous scent gland morphology and the size of the dorsal paracloacal glands of males, suggests that the dorsal paracloacal glands, or more likely their secretions, are important in social organization in this species.
Adrian J. Bradley - One of the best experts on this subject based on the ideXlab platform.
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Plasma androgen, social position, and response to GnRH in the marsupial sugar glider Petaurus breviceps (Marsupialia: Petauridae)
Journal of Zoology, 1997Co-Authors: Adrian J. Bradley, D. M. StoddartAbstract:The effect of gonadotrophin-releasing hormone GnRH on plasma testosterone was examined in male sugar gliders Petaurus breviceps that were judged to occupy either the highest or lowest position in stable colonies consisting of up to four males and two females. Experiment were carried out at a time when breeding occurred in two of the three colonies, as evidenced by the presence of pouch young.
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Behavioral and endocrinological correlates of social status in the male sugar glider (Petaurus breviceps Marsupialia: Petauridae).
Physiology & behavior, 1994Co-Authors: J. Mallick, D. M. Stoddart, Ivor H. Jones, Adrian J. BradleyAbstract:Socially dominant male sugar gliders are heavier than socially subordinate males, have higher plasma testosterone and lower cortisol concentrations, win more social encounters, scan the arena more, scent-mark more, and are more active and move more quickly, even though they spend more time in the colony nesting box. When they are transferred into a foreign stable colony there is an impressive reversal of behavioral measures and a concomitant decrease in concentration of plasma testosterone and rise in cortisol that is apparent over the first 3 weeks of observation.
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The dorsal paracloacal gland and its relationship with seasonal changes in cutaneous scent gland morphology and plasma androgen in the marsupial sugar glider (Petaurus breviceps; Marsupialia: Petauridae)
Journal of Zoology, 1993Co-Authors: Adrian J. Bradley, D. M. StoddartAbstract:A study spanning two breeding seasons was carried out to examine changes in the size of the dorsal paracloacal glands and testes in the marsupial sugar glider Petaurus breviceps Waterhouse 1839. These changes were related to seasonal increases in the plasma testosterone concentration and to morphological changes in the frontal and gular cutaneous scent glands of males. Both dorsal paracloacal glands and testes underwent a seasonal cycle of development which reached its maximum during the June-September breeding season. These changes coincided with an increase in the plasma testosterone concentration and with the increase in activity of certain cell types within the frontal and gular glands. Castration caused a significant decrease in the size of the dorsal paracloacal glands, while androgen replacement was effective in restoring the glands to their pre-castration size thus demonstrating the influence of androgens upon the activity of these glands. The synchronization which exists between plasma testosterone concentration, cutaneous scent gland morphology and the size of the dorsal paracloacal glands of males, suggests that the dorsal paracloacal glands, or more likely their secretions, are important in social organization in this species.
Stephen M. Jackson - One of the best experts on this subject based on the ideXlab platform.
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Petaurus gracilis (Diprotodontia: Petauridae)
Mammalian Species, 2011Co-Authors: Stephen M. JacksonAbstract:Petaurus gracilis (De Vis, 1883) is a gliding possum commonly known as the mahogany glider. This species is endemic to open sclerophyll woodland between Tully and Ingham in North Queensland, Australia. Within its distribution P. gracilis occurs in forests dominated by trees of the genera Eucalyptus, Corymbia, Melaleuca, and Acacia. This species is recognized as an endangered species because of habitat loss, high degree of fragmentation of the remaining habitat, its naturally limited distribution, lack of habitat protected within national parks, and the degradation of its habitat from the transition to rain forest and thickening of sclerophyllous vegetation in much of its habitat.
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time allocation to foraging in the mahogany glider petaurus gracilis marsupialia Petauridae and a comparison of activity times in exudivorous and folivorous possums and gliders
Journal of Zoology, 2006Co-Authors: Stephen M. Jackson, Christopher N JohnsonAbstract:The timing and duration of activity and foraging behaviour of mahogany gliders Petaurus gracilis was studied every 2 months over 2 years by direct observation. The amount of time spent active each night throughout the year ranged from 8 to 10.1 h (or 63–80% of the dark phase) and did not change significantly between the wet and dry seasons. Although gliders generally had one continuous period of activity, they were observed on eight occasions to return to their dens during the night for a mean of 85 min, with a mean entrance and exit being 22:59 and 00:25, respectively. The amount of time spent foraging (i.e. feeding and travelling) ranged from 40% of the time outside the den in January to 77% in September. The overall mean was 61.1%, with the remainder of the night spent either stationary (mean 24.3%), grooming (mean 11.8%), in the den and then re-emerging (mean 2.5%) or vocalizing (mean 0.3%). Activity comprised mostly the behaviours associated with foraging: feeding (44.9%), climbing (13.2%) and gliding (3.0%). The amount of time spent active and feeding was similar to that observed for other petaurid marsupials such as yellow-bellied glider P. australis, sugar glider P. breviceps and squirrel glider P. norfolcensis. There is a general relationship between diet, body size and amount of time spent feeding among the exudivorous gliders and folivorous possums, with feeding time increasing with increasing body mass in exudivorous possums and decreasing with increasing body mass in folivorous possums.
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foraging behaviour and food availability of the mahogany glider petaurus gracilis Petauridae marsupialia
Journal of Zoology, 2001Co-Authors: Stephen M. JacksonAbstract:The mahogany glider Petaurus gracilis is an endangered species of gliding possum that is only found within a limited distribution in North Queensland, Australia. The foraging behaviour of the mahogany glider was examined to determine how it changes seasonally, by extensive observations of radio-collared animals over a 2-year period. A total of 440 h was spent following mahogany gliders, of which 222 h of feeding behaviour was observed. Nectar and pollen were clearly the most important food items, comprising between 50 and 99% (mean 72.8%) of the observed feeding time when available. Nectar and pollen were consumed almost exclusively from Myrtaceae species with Eucalyptus, Corymbia and Melaleuca being eaten. Casual observations of a number of faecal samples showed that c. 80% of pollen grains were digested suggesting that pollen is a major source of protein. Other food items consumed included sap from Albizia procera and Acacia mangium, insects, lerps and honeydew, Acacia arils and fruit from mistletoes. In using these food items, the mahogany glider relied on complex seasonal cycles of food availability, requiring a high diversity of plants, with each species having distinct periods when it provides food during the year.
J. Mallick - One of the best experts on this subject based on the ideXlab platform.
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plasma testosterone concentration body weight social dominance and scent marking in male marsupial sugar gliders petaurus breviceps marsupialia Petauridae
Journal of Zoology, 1994Co-Authors: D. M. Stoddart, A J Bradley, J. MallickAbstract:Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live-trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body weight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the heaviest. In captivity this male is observed to be socially the most dominant and undertakes almost all of the scent-marking. At least three-quarters of each breeding season's births occur during the first month of the three- to four-month season (July-September/October), a passage of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits of high social status being immense.
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Behavioral and endocrinological correlates of social status in the male sugar glider (Petaurus breviceps Marsupialia: Petauridae).
Physiology & behavior, 1994Co-Authors: J. Mallick, D. M. Stoddart, Ivor H. Jones, Adrian J. BradleyAbstract:Socially dominant male sugar gliders are heavier than socially subordinate males, have higher plasma testosterone and lower cortisol concentrations, win more social encounters, scan the arena more, scent-mark more, and are more active and move more quickly, even though they spend more time in the colony nesting box. When they are transferred into a foreign stable colony there is an impressive reversal of behavioral measures and a concomitant decrease in concentration of plasma testosterone and rise in cortisol that is apparent over the first 3 weeks of observation.
Kathrine A Handasyde - One of the best experts on this subject based on the ideXlab platform.
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a set of microsatellite primers for the striped possum dactylopsila trivirgata Petauridae marsupialia
Molecular Ecology, 2003Co-Authors: Birgita D Hansen, Jordan French, Kathrine A Handasyde, T A Kendal, Andrea Carolyn TaylorAbstract:The New Guinean endemic dactylopsilines are members of the Petauridae possum family, represented in Australia only by the striped possum Dactylopsila trivirgata. The shy nature and low density of this species have hampered studies of its ecology to date, so we developed nine highly variable polymorphic microsatellite markers to enable molecular genetic analysis of population structure and mating system parameters. This will add substantially to our understanding of the behavioural ecology of this species. The low degree of cross-amplification of the primers in other petaurid species lends weight to other evidence suggesting that this family underwent a relatively early radiation.
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the feeding ecology of the striped possum dactylopsila trivirgata marsupialia Petauridae in far north queensland australia
Journal of Zoology, 2002Co-Authors: D R Rawlins, Kathrine A HandasydeAbstract:The diet of striped possums Dactylopsila trivirgata inhabiting the tropical forests of far north Queensland, Australia, was investigated by observing foraging behaviour and analysing stomach samples collected opportunistically from dead animals. In contrast to non-dactylopsiline petaurids, which frequently use plant exudates as well as invertebrates, observations on the foraging behaviour of D. trivirgata indicate that it is an opportunistic forager feeding mainly on invertebrates. Animals occasionally fed on plant exudates but these contributed little to the diet. Nine different orders of invertebrates were present in stomach samples, with wood boring coleopteran and lepidopteran larvae, and adult hymenopterans and isopterans being most frequently represented in the diet. This is consistent with the unusual morphological characteristics of D. trivirgata's, such as their elongated fourth finger and powerful jaws, which appear to be adaptations for extracting prey such as wood-boring larvae. Two of the important prey taxa in the diet (alates of Formicidae, and larvae of Cerambycidae) had a very high fat content (44% and 40% of dry weight, respectively) suggesting that the animals may target prey of high nutritional value. Anatomical investigations indicated that, relative to body weight, the digestive tract of D. trivirgata was shorter than that of most other petaurids. These data further support the idea that D. trivirgata is more reliant on invertebrates than other members of the family Petauridae.