Comparative Thermal Physiological Ecology of Syntopic Populations ofCacama valvataandTibicen bifidus(Homoptera: Cicadidae): Modeling Fitness Consequences of Temperature Variation

Autor: Eric C. Toolson
Rok vydání: 1998
Předmět:
Zdroj: American Zoologist. 38:568-582
ISSN: 0003-1569
DOI: 10.1093/icb/38.3.568
Popis: SYNOPSIS. This paper develops a model based on egg-laying rates and female oviposition temperature preferences in two species of cicada, Cacama valvata and Tibicen bifidus, from a central New Mexico desert grassland habitat. Output from the model indicates that C. valvata achieves maximal daily egg production (eggs female-' day-1) on days when maximum shade ambient temperatures reach 41*C; the corresponding value for T. bifidus is 33*C. These differences correlate with the thermal regime experienced by each species in its respective typical habitat. Simulations of the effects of variation in mean habitat ambient temperature on egg production demonstrated that known distributional limits for T. bifidus correspond to thermal conditions that reduce daily egg production by only about 5-10% relative to long-term means at the study site. The same is true for C. valvata only in lower-ambient temperature habitats. In higher-temperature habitats, C. valvata exhibits an unusual plasticity in the timing of adult activity and reproduction that allows it to occupy a much wider geographic range than T. bifidus. Contrary to expectations, frequency distributions of predicted daily egg production rates were negatively skewed in each species' respective 'typical habitat', and Gaussian only in thermally marginal habitats. The findings are discussed in the context of attempts to model population- and community-level effects of climatic change.
Databáze: OpenAIRE