title: 'Optimal thermal range' in ectotherms: Defining criteria for tests of the temperature-size-rule.
abstract: Thermal performance curves for population growth rate r (a measure of fitness) were estimated over a wide range of temperature for three species: Coleps hirtus (Protista), Lecane inermis (Rotifera) and Aeolosoma hemprichi (Oligochaeta). We measured individual body size and examined if predictions for the temperature-size rule (TSR) were valid for different temperatures. All three organisms investigated follow the TSR, but only over a specific range between minimal and optimal temperatures, while maintenance at temperatures beyond this range showed the opposite pattern in these taxa. We consider minimal and optimal temperatures to be species-specific, and moreover delineate a physiological range outside of which an ectotherm is constrained against displaying size plasticity in response to temperature. This thermal range concept has important implications for general size-temperature studies. Furthermore, the concept of 'operating thermal conditions' may provide a new approach to (i) defining criteria required for investigating and interpreting temperature effects, and (ii) providing a novel interpretation for many cases in which species do not conform to the TSR.
authors: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland. Electronic address: aleksandra.walczynska@uj.edu.pl.
authors: Aleksandra
authors: A
authors: Walczyńska
authors: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
authors: Anna
authors: A
authors: Kiełbasa
authors: Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
authors: Mateusz
authors: M
authors: Sobczyk
mesh_terms: D000818:Animals; D049628:Body Size; D016798:Ciliophora / Q000254:growth & development*; D009835:Oligochaeta / Q000254:growth & development*; D012403:Rotifera / Q000254:growth & development*; D013045:Species Specificity; D013696:Temperature
keywords: Fitness; Performance; Size; Temperature