Ecological and physiological aspects of reproductive strategies in two lizards

Journal Article · · Ecology; (United States)

OSTI ID:7227780

Derickson, W K

Two lizard species, the northern prairie lizard (Sceloporus undulatus garmani) from Reno County, Kansas, and the northern sagebrush lizard (Sceloporus graciosus graciosus) from Washington County, Utah, were used to test four hypotheses and one assumption related to the theory of r- and K-selection. The northern prairie lizard is short-lived, matures early, and has a high reproductive effort (r-strategist) while the northern sagebrush lizard is long-lived, has delayed maturity, and a low reproductive effort (K-strategist). One of the assumptions of the r- and K-selection theory is that competition for food is more intense for K-strategists than for r-strategists. Given this assumption, greater food availability for the prairie lizard was hypothesized to result in (1) a higher level of body lipids, (2) a higher rate of lipid utilization, (3) a lower percentage of ingested energy available for metabolism, and (4) an expenditure of less energy per offspring than in the sagebrush lizard. Total lipid levels in the two species collected before and after hibernation indicated that prairie lizards had significantly higher lipid levels than sagebrush lizards during both collection periods. Sagebrush lizards apparently are better adapted physiologically to lower food levels since they had lower rates of lipid utilization during starvation studies and they extracted more energy usable for metabolism from ingested food than prairie lizards. Prairie lizards produced more offspring per clutch and therefore expended less energy per offspring. Prairie lizards produced as many as three clutches per season as compared to two clutches per season for sagebrush lizards. Higher precipitation levels (indicating greater insect biomass) occurred at the prairie lizard collection site and this species had a smaller mouthgape index, indicating greater specialization in utilization of prey sites. (auth)

• Research Organization: Kansas State Univ., Manhattan
• OSTI ID: 7227780
• Journal Information: Ecology; (United States), Journal Name: Ecology; (United States) Vol. 57:3; ISSN ECOLA
• Country of Publication: United States
• Language: English

Related Subjects

510100 -- Environment
Terrestrial-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
550000* -- Biomedical Sciences
Basic Studies
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ARTHROPODS
AVAILABILITY
BIOMASS
DIGESTIVE SYSTEM
ECOLOGY
EGGS
ENERGY
ENERGY SOURCES
FASTING
FOOD
HIBERNATION
HYPOTHESIS
INSECTS
INVERTEBRATES
KANSAS
LIPIDS
LIZARDS
METABOLISM
MIDWEST REGION
MORTALITY
NORTH AMERICA
ORAL CAVITY
ORGANIC COMPOUNDS
PHYSIOLOGY
PRECIPITATION
PROGENY
RENEWABLE ENERGY SOURCES
REPRODUCTION
REPTILES
ROCKY MOUNTAIN REGION
SEPARATION PROCESSES
SIZE
USA
UTAH
VERTEBRATES