Patterns of morphological divergence in fruit fly: response to nutritional variations through changes in allometric relationships and trait sizes

• Published in: Journal of zoology (1987) Vol. 309; no. 1; pp. 22 - 34
• Main Authors: Bhumika, Singh, A. K.
• Format: Journal Article
• Language: English
• Published: London Blackwell Publishing Ltd 01.09.2019
• Subjects: Accommodation; allometric relationship; Allometry; Animal morphology; Body size; Carbohydrates; Chromosomes; Composition effects; Developmental plasticity; Dimensions; Divergence; Drosophila ananassae; Ecological monitoring; Environmental conditions; Fruit flies; Genetic diversity; Genotypes; Individual rearing; morphological divergence; morphological evolution; Morphology; Natural environment; Norms; Nutritional ecology; Plastic properties; Plasticity; Proteins; Scaling; Shape; Slope; Stocks; Sucrose; Sugar; Wings
• ISSN: 0952-8369; 1469-7998
• DOI: 10.1111/jzo.12680

The morphological structures of organisms may be subject to divergence when exposed to varied nutritive conditions, due to the occurrence of developmental plasticity and its fixation due to the process of genetic accommodation. The allometric relationship of traits with respect to each other and to the whole body defines the shape of an individual. Developmental plasticity in different nutritional regimes affects the absolute value of traits and its relative scaling with respect to body size. We investigated the diversification in wing dimensions and body size in Drosophila ananassae by utilizing isofemale lines of Bilaspur and karyotypically characterized stocks of Varanasi, by rearing flies in nutritional regimes having differences in protein and carbohydrate compositions. The effect of dietary protein variations on plasticity of absolute size of body and wing dimensions was found to be highly genotype‐dependent as compared to sucrose, in both the sexes and in both the populations. This suggests that variation in proteins in natural environment may induce greater selective pressure on traits and may lead to diversification in morphological structures due to the process of genetic accommodation. We found highly significant genetic variation in plasticity for allometric relationship in Bilaspur population for variations in protein as well as carbohydrate in dietary media. However, constraints in plasticity of allometric slopes for wing dimensions in karyotypic stocks of Varanasi were found in response to both the nutritional variations. The analysis of reaction norms also suggested that there is involvement of alpha inversion present in 2L chromosome of Varanasi population, in adapting to different nutritional environmental conditions due to changes in static allometry of different wing dimensions. Overall, this study reveals that the nutritional ecology and evolutionary allometry govern the morphological divergence of traits size and shape in a genotypic‐dependent manner, thereby resulting in morphological evolutions. The morphological structures of organisms may be subject to divergence when exposed to varied nutritive conditions, due to the occurrence of developmental plasticity and its fixation due to the process of genetic accommodation. We investigated the diversification in wing dimensions and body size in Drosophila ananassae by utilizing isofemale lines of Bilaspur and karyotypically characterized stocks of Varanasi, by rearing flies in nutritional regimes having differences in protein and carbohydrate compositions. The study emphasizes the importance of nutritional ecology and evolutionary allometry in governing the morphological divergence of traits size and shape in a genotypic‐dependent manner, thereby resulting in morphological evolutions.