title: Effects of within-generation thermal history on the flight performance of Ceratitis capitata: colder is better.
abstract: The influence of thermal history on temperature-dependent flight performance was investigated in an invasive agricultural pest insect, Ceratitis capitata (Diptera: Tephritidae). Flies were exposed to one of four developmental acclimation temperatures (Tacc: 15, 20, 25, 30°C) during their pupal stage and tested at these temperatures (Ttest) as adults using a full-factorial study design. Major factors influencing flight performance included sex, body mass, Ttest and the interaction between Ttest and Tacc. Successful flight performance increased with increasing Ttest across all acclimation groups (from 10% at 15°C to 77% at 30°C). Although Tacc did not affect flight performance independently, it did have a significant interaction effect with Ttest. Multiple comparisons showed that flies which had been acclimated to 15°C and 20°C performed better than those acclimated to 25°C and 30°C when tested at cold temperatures, but warm-acclimated flies did not outperform cold-acclimated flies at warmer temperatures. This provides partial support for the 'colder is better' hypothesis. To explain these results, several flight-related traits were examined to determine whether Tacc influenced flight performance as a consequence of changes in body or wing morphology, whole-animal metabolic rate or cytochrome c oxidase enzyme activity. Although significant effects of Tacc could be detected in several of the traits examined, with an emphasis on sex-related differences, increased flight performance could not be explained solely on the basis of changes in any of these traits. Overall, these results are important for understanding dispersal physiology despite the fact that the mechanisms of acclimation-related changes in flight performance remain unresolved.
authors.affiliation: Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
authors.forename: Nanike
authors.initials: N
authors.lastname: Esterhuizen
authors.affiliation: Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
authors.forename: Susana
authors.initials: S
authors.lastname: Clusella-Trullas
authors.affiliation: Department of Electrical and Electronic Engineering, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
authors.forename: Corne E
authors.initials: CE
authors.lastname: van Daalen
authors.affiliation: Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
authors.forename: Ruben E
authors.initials: RE
authors.lastname: Schoombie
authors.affiliation: Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa.
authors.forename: Leigh
authors.initials: L
authors.lastname: Boardman
authors.affiliation: Department of Conservation Ecology and Entomology, Stellenbosch University, Private Bag X1, Matieland 7602, Stellenbosch, South Africa jst@sun.ac.za.
authors.forename: John S
authors.initials: JS
authors.lastname: Terblanche
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D001835:Body Weight; D033622:Ceratitis capitata / Q000254:growth & development* / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005426:Flight, Animal / Q000502:physiology*; D008297:Male; D010641:Phenotype; D012044:Regression Analysis; D012737:Sex Factors; D013696:Temperature; D014921:Wings, Animal / Q000254:growth & development* / Q000502:physiology*
chemical_list: D003576:Electron Transport Complex IV
keywords: Beneficial acclimation hypothesis; Developmental variation; Mediterranean fruit fly; Phenotypic plasticity