Interhabitat Differences in Energy Acquisition and Expenditure in a Lizard

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology. Abstract. Cnemidophorus hyperythrus, a small (z4-g) teiid lizard, occurs along an elevational thorn scrub-thorn woodland-thorn forest habitat gradient in the cape region of Baja California. We compared body size, daily energy expenditure (DEE, measured with doubly labeled water), relative feeding rate (as reflected by H20 influx rate), behavior, and abundance of this species at two sites along the gradient. At the inland thorn woodland site C. hyperythrus were more abundant (; 100 lizards/ha) than at the thorn scrub site near the ocean (I 50 lizards/ha). Mean body mass of woodland site lizards was 13% greater than that of scrub lizards. The DEE of the thorn woodland lizards, 330 J g-1 ld-l, and their H20 influx, 99 mm3 g-l d-, were also higher than the thorn scrub lizards', 219 J g-l d-I and 52 mm3 g-l dl. Diets at the two sites were similar. There were no differences between sexes in diet, DEE, or H20 influx.Daily maintenance energy costs were calculated based upon laboratory measures of 02 consumption of resting lizards at a series of temperatures that represented the daily range of body temperatures experienced by lizards in the field. Activity costs (=DEE minus maintenance) were three times higher in the woodland lizards. Behavioral observations showed that woodland lizards were active most of the day (z9 h/d) whereas scrub lizards were active primarily in the morning (z3.5 h/d). Thus, the higher activity cost, DEE, and feeding rate of woodland lizards can be explained by their longer daily activity period. We suggest causal factors for the difference in daily activity period, and discuss implications of length of daily foraging period for adult body size, population density, and various life history parameters of lizards.

Diet, microhabitat use, and thermal preferences of Ptychoglossus bicolor (Squamata: Gymnophthalmidae) in an organic coffee shade plantation in Colombia

“…Maintenance of T b significantly higher than T a may reflect a behavioral mechanism for gaining heat (Verwaijen & Van Damme, 2007); P. bicolor probably use small sunlit patches in the leaf litter of the coffee shade plantation, as do gymnophthalmids in Amazonian rainforests (Vitt et al, 2003b). This ability to perform with such a low body temperature may reflect the highly abundant source of food, promoting a more passive foraging mode that allows them to be active during cloudy days and in cold microhabitats (Karasov & Anderson, 1984;Verwaijen & Van Damme, 2007). The significant relationships observed between T b , T a and T s suggest that microhabitats might be chosen at least partially on the basis of temperature; however, other factors may influence P. bicolor microhabitat preferences as stated above.…”

Increased energy expenditure due to increased territorial defense in male lizards after phenotypic manipulation

“…Increased activity from the 54% longer daily activity periods (Marler and Moore 1989) of the T-implanted males may also contribute to the 31% increase in energy expenditure. The teiid lizard Cnemidophorus hyperythrus is active 60% longer in woodland areas compared to scrub areas and has a corresponding 52% higher energy expenditure (Karasov and Anderson 1984). Estimates suggest that for lizards in the woodland areas, 83% of energetic costs is caused by increased activity and the remaining 17 % is caused by the higher body temperature during increased activity, suggesting that the increase in activity has a greater impact on the energy budget than changes in temperature.…”

The Effects of Diverse Habitats in Urra on Lizard Abundance

“…There was no minimum adequate model because even when the two way interaction terms were omitted individually (wind speed × air temperature; wind speed × habitat; air temperature × habitat), to reveal just the main effects, the model was still insignificant (habitat: Stamps (1983) showed that vegetation structure played a critical role in reptile habitat selection for predator escape. Additionally, this vegetation cover has also been used for foraging (Karasov and Anderson, 1984), and mating (Diaz and Carrascal, 1991). Algyroides marchi is a lizard endemic to the mountainous region of south-east Iberian Peninsula.…”