adapting to an invasive species: toxic cane toads induce morphological change in australian snakes.the arrival of invasive species can devastate natural ecosystems, but the long-term effects of invasion are less clear. if native organisms can adapt to the presence of the invader, the severity of impact will decline with time. in australia, invasive cane toads (bufo marinus) are highly toxic to most snakes that attempt to eat them. because snakes are gape-limited predators with strong negative allometry for head size, maximum relative prey mass (and thus, the probability of eating a toad large ...200415569943
adapting to the unpredictable: reproductive biology of vertebrates in the australian wet-dry the wet-dry tropics of northern australia, temperatures are high and stable year-round but monsoonal rainfall is highly seasonal and variable both annually and spatially. many features of reproduction in vertebrates of this region may be adaptations to dealing with this unpredictable variation in precipitation, notably by (i) using direct proximate (rainfall-affected) cues to synchronize the timing and extent of breeding with rainfall events, (ii) placing the eggs or offspring in conditions w ...200817638689
pathogenicity in six australian reptile species following experimental inoculation with bohle iridovirus.ranaviruses are able to infect multiple species of fish, amphibian and reptile, and some strains are capable of interclass transmission. these numerous potential carriers and reservoir species compound efforts to control and contain infections in cultured and wild populations, and a comprehensive knowledge of susceptible species and life stage is necessary to inform such processes. here we report on the challenge of 6 water-associated reptiles with bohle iridovirus (biv) to investigate its poten ...201526290505
serological survey of australian native reptiles for exposure to ranavirus.ranaviruses have been isolated from many ectothermic vertebrates, and serological surveys of both amphibians and reptiles have shown the presence of ranaviral antibodies in a proportion of these populations. an enzyme-linked immunosorbent assay (elisa) was developed to measure serum antibodies against ranavirus in australian reptiles. the elisa was validated with serum from challenge trials with bohle iridovirus (biv) in 6 reptilian species. a preliminary sero-survey of northern queensland ripar ...201729160216
maternal body size influences offspring immune configuration in an oviparous most ectothermic vertebrates, keelback snakes (tropidonophis mairii) do not exhibit parental care. thus, offspring must possess an immune system capable of dealing with challenges such as pathogens, without assistance from an attendant parent. we know very little about immune system characteristics of neonatal reptiles, including the magnitude of heritability and other maternal influences. to identify sources of variation in circulating white blood cell (wbc) concentrations and differential ...201627069670
detrimental influence on performance of high temperature incubation in a tropical reptile: is cooler better in the tropics?global temperatures have risen over the last century, and are forecast to continue rising. ectotherms may be particularly sensitive to changes in thermal regimes, and tropical ectotherms are more likely than temperate species to be influenced by changes in environmental temperature, because they may have evolved narrow thermal tolerances. keelback snakes (tropidonophis mairii) are tropical, oviparous reptiles. to quantify the effects of temperature on the morphology and physiology of hatchling k ...201322782497
beyond size-number trade-offs: clutch size as a maternal effect.traditionally, research on life-history traits has viewed the link between clutch size and offspring size as a straightforward linear trade-off; the product of these two components is taken as a measure of maternal reproductive output. investing more per egg results in fewer but larger eggs and, hence, offspring. this simple size-number trade-off has proved attractive to modellers, but our experimental studies on keelback snakes (tropidonophis mairii, colubridae) reveal a more complex relationsh ...200919324614
rain, prey and predators: climatically driven shifts in frog abundance modify reproductive allometry in a tropical predict the impacts of climate change on animal populations, we need long-term data sets on the effects of annual climatic variation on the demographic traits (growth, survival, reproductive output) that determine population viability. one frequent complication is that fecundity also depends upon maternal body size, a trait that often spans a wide range within a single population. during an eight-year field study, we measured annual variation in weather conditions, frog abundance and snake re ...200717724615
repeatability and heritability of reproductive traits in free-ranging snakes.the underlying genetic basis of life-history traits in free-ranging animals is critical to the effects of selection on such traits, but logistical constraints mean that such data are rarely available. our long-term ecological studies on free-ranging oviparous snakes (keelbacks, tropidonophis mairii (gray, 1841), colubridae) on an australian floodplain provide the first such data for any tropical reptile. all size-corrected reproductive traits (egg mass, clutch size, clutch mass and post-partum m ...200717305825
like mother, like daughter: inheritance of nest-site location in snakes.a trait can be passed from parents to offspring even if it has no genetic basis. for example, if daughters return to reproduce at the same sites where they were hatched themselves, nest-site location is consistent within matrilineages. most cases of natal homing (nest-site philopatry) across generations have been inferred from molecular evidence rather than directly demonstrated, and involve species with low dispersal abilities. however, some animals disperse long distances but then return to th ...200717284402
why do most tropical animals reproduce seasonally? testing hypotheses on an australian snake.most species reproduce seasonally, even in the tropics where activity occurs year-round. squamate reptiles provide ideal model organisms to clarify the ultimate (adaptive) reasons for the restriction of reproduction to specific times of year. females of almost all temperate-zone reptile species produce their eggs or offspring in the warmest time of the year, thereby synchronizing embryogenesis with high ambient temperatures. however, although tropical reptiles are freed from this thermal constra ...200616634304
do changing moisture levels during incubation influence phenotypic traits of hatchling snakes (tropidonophis mairii, colubridae)?phenotypic traits (e.g., size, strength, speed) of hatchlings in many reptile species are influenced by hydric conditions in the nest. previous experiments have focused on comparisons between eggs maintained under constant (but different) conditions, but eggs in natural nests frequently experience strong temporal shifts in soil water content during incubation. keelback snakes (tropidonophis mairii) in the australian wet-dry tropics nest over most of the year, so early nests experience decreasing ...201315957107
immune configuration in hatchling snakes is affected by incubation moisture, and is linked to subsequent growth and survival in the field.we incubated the eggs of field-caught keelback snakes (tropidonophis mairii) on wet versus dry substrates to explore impacts of incubation conditions on white blood cell (wbc) concentrations and differential wbc counts of hatchlings. in a second, independent study young snakes were released into the field, allowing us to explore fitness correlates of wbc profiles. dry incubation reduced embryonic survival and hatchling body size, thus decoupling egg size from hatchling size. incubation condition ...201829578642
ontogenetic shifts in a prey's chemical defences influence feeding responses of a snake predator.foraging theory suggests that predator responses to potential prey should be influenced by prey chemical defences, but the effects of ontogenetic variation in such defences on prey vulnerability to predators remain unclear. cane toads (rhinella marina) are toxic to anurophagous snakes, including the keelback (tropidonophis mairii, a natricine colubrid that occurs within the toads' invasive range in australia). toxin levels and diversity change through toad ontogeny, decreasing from the egg stage ...201222302513
Displaying items 1 - 14 of 14