SIMILARITIES AND DIFFERENCES IN ALTITUDINAL VERSUS LATITUDINAL VARIATION FOR MORPHOLOGICAL TRAITS IN DROSOPHILA MELANOGASTER

• Published in: Evolution Vol. 68; no. 5; pp. 1385 - 1398
• Main Authors: Klepsatel, Peter, Gáliková, Martina, Huber, Christian D., Flatt, Thomas
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.05.2014; Wiley Subscription Services, Inc; Oxford University Press
• Subjects: Altitude; Animals; Body Size; cell number; Climate; Clines; Drosophila; Drosophila melanogaster; Drosophila melanogaster - anatomy & histology; Drosophila melanogaster - genetics; Ecosystem; Egg production; Evolution; Evolutionary biology; Female; Gene-Environment Interaction; Genetic Variation; Genitalia, Female - anatomy & histology; Genotype & phenotype; Insect morphology; Insects; latitude; Manipulation; Morphology; Natural environment; Natural populations; ovariole number; Ovarioles; Phenotypic traits; Phenotypic variations; Thorax; Transgenic animals; Wing loading; Wings, Animal - anatomy & histology; latitude; body size; ovariole number; wing loading; Altitude; cell number; clines
• ISSN: 0014-3820; 1558-5646; 1558-5646
• DOI: 10.1111/evo.12351

Understanding how natural environments shape phenotypic variation is a major aim in evolutionary biology. Here, we have examined clinal, likely genetically based variation in morphology among 19 populations of the fruit fly (Drosophila melanogaster) from Africa and Europe, spanning a range from sea level to 3000 m altitude and including locations approximating the southern and northern range limit. We were interested in testing whether latitude and altitude have similar phenotypic effects, as has often been postulated. Both latitude and altitude were positively correlated with wing area, overiole number, and cell number. In contrast, latitude and altitude had opposite effects on the ratio between overiole number and body size, which was negatively correlated with egg production rate per overiole. We also used transgenic manipulation to examine how increased cell number affects morphology and found that larger transgenic flies, due to a higher number of cells, had more overioles, larger wings, and, unlike flies from natural populations, increased wing loading. Clinal patterns in morphology are thus not a simple function of changes in body size; instead, each trait might be subject to different selection pressures. Together, our results provide compelling evidence for profound similarities as well as differences between phenotypic effects of latitude and altitude.