title: Effects of ambient and preceding temperatures and metabolic genes on flight metabolism in the Glanville fritillary butterfly.
abstract: Flight is essential for foraging, mate searching and dispersal in many insects, but flight metabolism in ectotherms is strongly constrained by temperature. Thermal conditions vary greatly in natural populations and may hence restrict fitness-related activities. Working on the Glanville fritillary butterfly (Melitaea cinxia), we studied the effects of temperature experienced during the first 2 days of adult life on flight metabolism, genetic associations between flight metabolic rate and variation in candidate metabolic genes, and genotype-temperature interactions. The maximal flight performance was reduced by 17% by 2 days of low ambient temperature (15 °C) prior to the flight trial, mimicking conditions that butterflies commonly encounter in nature. A SNP in phosphoglucose isomerase (Pgi) had a significant association on flight metabolic rate in males and a SNP in triosephosphate isomerase (Tpi) was significantly associated with flight metabolic rate in females. In the Pgi SNP, AC heterozygotes had higher flight metabolic rate than AA homozygotes following low preceding temperature, but the trend was reversed following high preceding temperature, consistent with previous results on genotype-temperature interaction for this SNP. We suggest that these results on 2-day old butterflies reflect thermal effect on the maturation of flight muscles. These results highlight the consequences of variation in thermal conditions on the time scale of days, and they contribute to a better understanding of the complex dynamics of flight metabolism and flight-related activities under conditions that are relevant for natural populations living under variable thermal conditions.
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland. Electronic address: swee.wong@helsinki.fi.
authors.forename: Swee Chong
authors.initials: SC
authors.lastname: Wong
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland; Department of Biology, P.O. Box 111, 80101 University of Eastern Finland, Joensuu, Finland.
authors.forename: Alma
authors.initials: A
authors.lastname: Oksanen
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland.
authors.forename: Anniina L K
authors.initials: AL
authors.lastname: Mattila
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland; Institute of Biomedicine & Genome-Scale Biology Research Program Biomedicum 1, P.O. Box 63, 00014 University of Helsinki, Finland.
authors.forename: Rainer
authors.initials: R
authors.lastname: Lehtonen
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland.
authors.forename: Kristjan
authors.initials: K
authors.lastname: Niitepõld
authors.affiliation: Department of Biosciences, P.O. Box 65, 00014 University of Helsinki, Finland.
authors.forename: Ilkka
authors.initials: I
authors.lastname: Hanski
mesh_terms: D000818:Animals; D002080:Butterflies / Q000235:genetics / Q000502:physiology*; D005260:Female; D005426:Flight, Animal; D005838:Genotype; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D013696:Temperature
chemical_list: D019476:Insect Proteins
keywords: Flight metabolic rate; Flight muscle maturation; Pgi; Temperature treatment; Temperature–genotype interaction; Tpi