Life history and ecology of the elegant snake-eyed skink (Cryptoblepharus pulcher) in south-eastern Australia

2019 ◽  
Vol 67 (1) ◽  
pp. 51
Author(s):  
David A. Pike ◽  
Elizabeth A. Roznik ◽  
Jonathan K. Webb ◽  
Richard Shine

Detailed information on life history and ecology is essential for successful conservation and management. However, we have relatively little detailed data on the life history and ecology of most small lizard species, relative to other vertebrates, especially those that have undergone recent taxonomic changes. We studied the ecology of the elegant snake-eyed skink (Cryptoblepharus pulcher), a lizard that occurs on trees, fences, walls, and rock outcroppings in eastern Australia that spans temperate to tropical environments. In our temperate-zone study population living in natural habitat, individuals are active year-round, and gravid females were found during the months of September through December. Sexual maturity is reached in 12 months, lifespan is at least three years, and clutch size is typically two eggs. In laboratory incubation experiments, larger eggs were more likely to hatch. Low incubation temperatures (averaging 23 ± 7.5°C versus high temperatures averaging 26 ± 7.5°C) increased incubation duration significantly (range 56–72 days versus 40–51 days) and reduced the body size of hatchlings significantly (17.8 mm versus 18.7 mm snout–vent length). Skinks sheltered beneath small rocks that were not shared simultaneously with predatory snakes, and that reached average temperatures that were up to 3°C warmer during the day than unused rocks. Preferred microhabitats include substrates of rock or soil, and the largest rocks were occasionally shared by up to four individuals of all body size/sex combinations (5.8% of observations were shared, 30.2% of individual rocks were shared). Our study expands upon knowledge of the widespread genus Cryptoblepharus by providing detailed life history and ecological information on C. pulcher that can serve as a baseline for future studies.


1975 ◽  
Vol 53 (9) ◽  
pp. 1254-1257 ◽  
Author(s):  
Lawrence E. Licht

Comparisons are made of life history features of the western spotted frog, Rana pretiosa pretiosa, living at 70 m in southwestern British Columbia, and 2600 m in Yellowstone Park, Wyoming.Lowland tadpoles remain longer as larvae and transform at twice the body size as highland tadpoles.Growth rates of juveniles and adults are rapid in the lowland population and the same amount of growth achieved by them in 2–3 years takes 8–10 years for highland frogs.Body size at sexual maturity is the same for frogs from both populations, but B.C. frogs breed at half the age of Wyoming frogs. Female fecundity, the number of eggs at spawning, is the same, but lowland females breed annually, while high-elevation females breed only every 2 or 3 years.Various explanations are put forth to account for observed differences.



2003 ◽  
Vol 63 (3) ◽  
pp. 393-399 ◽  
Author(s):  
M. Cunha-Barros ◽  
M. Van Sluys ◽  
D. Vrcibradic ◽  
C. A. B. Galdino ◽  
F. H. Hatano ◽  
...  

We studied the parasitism by larvae of the chigger mite Eutrombicula alfreddugesi on the lizard community of Restinga de Jurubatiba, Rio de Janeiro State, Southeastern Brazil. We investigated the patterns of infestation (prevalence and intensity) of chigger mites in four sympatric lizards: Tropidurus torquatus, Mabuya agilis, M. macrorhyncha and Cnemidophorus littoralis. All lizards collected were checked for the presence of mites, which were counted under stereomicroscope. We tested the relationship between intensity of infestation and lizard body size for each species using regression analysis. The prevalences and mean intensities (+ one standard deviation) of infestation on each host species were, respectively: 100%; 86.4 + 94.6 in T. torquatus (n = 62); 100%; 20.9 + 9.3 in M. agilis (n = 7); 100%; 11.1 + 13.1 in M. macrorhyncha (n = 12); and 95.2%; 19.1 + 16.8 in C. littoralis (n = 21). Only for C. littoralis did body size significantly affect the intensity of infestation (r = 0.27, p = 0.02). For all lizard species, the body parts where chiggers occurred with the highest intensity were those of skin folds and joint regions.



2016 ◽  
Vol 64 (2) ◽  
pp. 91 ◽  
Author(s):  
S. Garnick ◽  
J. Di Stefano ◽  
M. A. Elgar ◽  
G. Coulson

Many theories attempt to explain patterns of community organisation among large herbivores. We explored the role of body size, diet type and residence time on habitat use in a community comprising four metatherians (western grey kangaroo, Macropus fuliginosus; eastern grey kangaroo, M. giganteus; red-necked wallaby, Notamacropus rufogriseus; swamp wallaby, Wallabia bicolor) and two eutherians (red deer, Cervus elaphus; European rabbit, Oryctolagus cuniculus) in south-eastern Australia. We used camera traps to estimate habitat occupancy, quantified habitat specialisation using relative entropy, and ran regressions using percentage grass consumed, log(mass) and log(time at site) as predictor variables and relative entropy as the response. If body size influenced habitat use, we predicted smaller species would occupy fewer habitats. If diet type influenced habitat use, we predicted intermediate feeders would use more habitats. If the time that a species had been present at a site predicted community organisation, newer species would use more habitats. None of these theories explained habitat use in our community. Red deer used a narrower range of habitats than expected, perhaps due to the poor suitability of habitats available in the Grampians. While interactions between our hypotheses are likely to be important, the body size model deserves further attention in this community.



2011 ◽  
Vol 59 (4) ◽  
pp. 201 ◽  
Author(s):  
Elise Furlan ◽  
J. Griffiths ◽  
N. Gust ◽  
R. Armistead ◽  
P. Mitrovski ◽  
...  

The body size of the platypus (Ornithorhynchus anatinus) is known to vary across both its latitudinal range and relatively short geographic distances. Here we consider how variation in platypus length and weight associates with environmental variables throughout the species’ range. Based on data from over 800 individuals, a Bergmann’s cline (increased body size in regions of lower temperature) was detected across the species latitudinal range. The opposite association, however, was present at smaller scales when comparing platypus body size and temperature within southern mainland Australia, or within an individual river basin. Temperature regimes alone clearly did not dictate body size in platypuses, although disentangling the effects of different climatic variables on body size variation was difficult because of correlations amongst variables. Nevertheless, within suitable platypus habitat in south-eastern Australia, areas of relatively lower rainfall and higher temperatures were typically associated with larger-bodied platypuses. The potential benefits to larger-bodied animals living under these conditions are explored, including consideration of variation in energy expenditure and food availability. Assuming these associations with environmental variables are biologically significant, a shift in platypus body size is anticipated in the future with predicted changes in climate.



2018 ◽  
Author(s):  
Daniel F. Hughes ◽  
Walter E. Meshaka

ABSTRACTWe ascertained various life-history traits from an examination of 310 museum specimens of the Rio Grande leopard frog (Lithobates berlandieriBaird, 1859) collected during 1907–2016 from Texas, USA.Lithobates berlandieriwas captured during every month of the year except November, and adults were most frequently encountered during January–September with a distinct peak in May. Mean body size of adult males (69.5 mm) was smaller than that of adult females (77.5 mm), and both sexes were larger in mean body sizes than those of New Mexico populations (M = 64.4 mm; F = 73.5 mm). Females were gravid during January–September, and most gravid females were captured from late-winter to early-summer. Gonadal enlargement in males was generally high throughout January–September with no detectable seasonal increase. Feeding became widespread in both sexes during May–June shortly after a spring breeding bout. Spent females were common in July and lipid deposition increased in June/July, signaling oogenesis for breeding in the fall. From 15 gravid females, we estimated a mean clutch size of 3,107 eggs which was correlated with female body size, yet egg diameter was not related to clutch or body size. Age to metamorphosis was likely 2 to 4 months depending upon whether eggs were laid in the winter/spring or late fall. If metamorphosis occurred in May/June, the minimum size at sexual maturity in adult males (50.1 mm) could have been reached in 3–4 months and in 6–7 months for adult females (57.2 mm). Mean adult body sizes, however, may have taken 12 to 17 months to reach. A synthesis across Texas populations suggests that the breeding season extends almost continuously from the fall through the winter and spring until mid-summer and is interrupted by winter and summer peaks in seasonal temperatures.



Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1137
Author(s):  
Heriberto López ◽  
Sandra Hervías-Parejo ◽  
Elena Morales ◽  
Salvador De La Cruz ◽  
Manuel Nogales

Insects show remarkable phenotypic plasticity in response to changing environmental conditions. The abiotic factors that determine their phenotypes often vary in time and space, and oceanic islands harbour ideal environments for testing predictions on this matter. The ubiquitous beetle Pimelia laevigata costipennis Wollaston, 1864 (Tenebrionidae) is distributed over the entire altitudinal gradient of the island El Hierro (Canary archipelago), from 0 to 1501 m above sea level. Here, we examine how environmental factors (i.e., rainfall and temperature), associated with the altitudinal gradient, affect the body size, reproductive phenology, clutch size and egg volume, and population dynamics of this ectothermic flightless insect. Pimelia l. costipennis populations inhabiting upland localities, typified by lower temperatures, and greater precipitation and vegetation cover, were larger in body size and laid larger clutches with smaller eggs than those in the lowlands. Moreover, reproduction occurred earlier in the year at lower sites and later at higher sites, whereas activity density was highest in the uplands where it increases with temperature. This study first explores the changes in life history patterns along a whole insular altitudinal gradient, and finds interpopulation plasticity. It confirms that environmental factors associated with species spatial distribution act additively as drivers of phenological and phenotypic expression.



Behaviour ◽  
1990 ◽  
Vol 112 (3-4) ◽  
pp. 162-175 ◽  
Author(s):  
Alicia Mathis

AbstractIntraspecific interference competition associated with territoriality has been documented in laboratory studies of the red-backed salamander, Plethodon cinereus. I used laboratory and field experiments to study the effect of resource quality and body size on such competition. In an experiment in southwestern Virginia, cover objects (e.g., logs) from which the resident salamanders were removed were invaded significantly more often than cover objects from which the resident salamander was not removed. These data provide the first direct test of territoriality for a salamander in a natural habitat. Newly invading salamanders were significantly smaller than the original territorial residents. Therefore, large body size is an advantage in territorial encounters. Because cover objects are important resources for terrestrial salamanders, characteristics of the cover object may contribute to territory quality. In an experiment conducted during warm summer weather at the Virginia site, soil temperatures under large cover objects were significantly cooler than those under small cover objects or under the leaf litter. Large cover objects may therefore benefit the salamanders by providing a buffer zone between the salamander and extreme environmental temperatures on the forest floor. In both laboratory and field experiments, when salamanders were offered a choice between large and small cover objects, both large and small salamanders exhibited a significant preference for large cover objects. Also I censused cover objects in a natural mixed hardwood forest habitat during courting and noncourting seasons and, for both seasons, I found a significant positive correlation between the body size of the salamander and the size of the cover object that it occupied. I conclude that, in this natural forest habitat, there is intraspecific competition for high quality cover objects and larger individuals are more successful competitors than smaller individuals.



Author(s):  
S. Obenat ◽  
E. Spivak ◽  
L. Garrido

The life history and reproductive biology of the gammaridean amphipod Melita palmata was studied in the Mar Chiquita coastal lagoon (Argentina). The animals were collected fortnightly or monthly from Ficopomatus enigmaticus reefs from December 2000 to March 2002. The population density reached a maximum of 1556.67±1560 ind/m3 (mean±SD) in March 2001, decreased dramatically after intense rainfalls in winter 2001, and had a minimum value of 141.67±27.54 ind/m3 (mean±SD) in March 2002. Size differed significantly between sexes. The maximum size of males was 11.5 mm and this was 1.4 times longer than the length of females. The average sex ratio (0.44) did not differ significantly from an expected 1:1 value. Ovigerous females were present from December to March, when the temperature was above 18°C. The body size of ovigerous females ranged from 2.9 to 6.81 mm. There was a positive correlation between the brood size and body length of ovigerous females, and the maximum number of eggs per female was ten. Recruitment took place during the whole breeding season; juveniles recruited at the beginning of the season matured at the end of the same season, those recruited late would probably reach maturity in the following season.



2004 ◽  
Vol 136 (6) ◽  
pp. 839-850 ◽  
Author(s):  
M.A.H. Smith ◽  
R.J. Lamb

AbstractThe body sizes of mature larvae and adults from field and laboratory populations of the wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were measured to determine possible causes of variation in size and consequences of such variation through the life history. Mature larvae varied eightfold in mass. Female larvae were 80% heavier than males, on average. Variation in mass was associated with both the position of larvae on a wheat spike and the number feeding together on a developing seed. Larvae were 9% smaller when they developed on smaller, later developing seeds and 15%–18% smaller when they competed with five other larvae on an average-sized seed. Fewer small larvae survived winter. Larval density per infested seed increased with number of larvae per spike, suggesting that larval size may have density-dependent population effects. Small larvae produced few adults of Macroglenes penetrans (Kirby) (Hymenoptera: Pteromalidae), an egg parasitoid that overwinters as a larva in the third larval instar of S. mosellana. These effects were probably due to size, but sex may also have been a factor. The size of adults, measured by wing and abdomen length, was also variable, although less so than the size of larvae. Adult size was not associated with time of emergence and both large and small females dispersed, but female fecundity (4–105 mature eggs per individual) increased with body size.





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