Mate choice and gene expression signatures associated with nutritional adaptation in the medfly (Ceratitis capitata)

Abstract

Evolutionary responses to nutrition are key to understanding host shifts and the resulting potential for reproductive isolation. Experimental evolution has previously been used to describe the responses of the medfly ( Ceratitis capitata ) to larval diets with different nutritional properties. Within 30 generations this led to divergence in larval development time, egg to adult survival and adaptation in adult body size. Here we used mRNA-seq to identify differences in gene expression patterns in these same populations, using males from the 60 th generation of nutritional selection. We validated differential expression by using qRT-PCR and found that genes linked to metabolism, oxidative phosphorylation and proteolysis were significantly over-represented among the differentially expressed genes. The results provide the first genome-wide survey of the putative mechanisms underpinning evolved responses to nutritional adaptation. In addition, we tested the hypothesis that nutritional adaptation can alter mating patterns. We found evidence for assortative mating by diet at generation 60, but not 90. Hence, the pattern was variable across generations and there was no evidence overall for any isolating mating divergence between the lines. Overall, the results provide insight into the mechanisms underpinning dietary adaptation and extend our knowledge of which traits represent core responses to nutritional selection.

Role of Genes in Regulating Host Plants Expansion in Tephritid Fruit Flies (Diptera) and Potential for RNAi-Based Control

“…To respond to various toxic environments, including secondary toxic chemicals of different hosts, B. dorsalis primarily triggered the delta subfamily of GSTs, CYP3 and CYP4 subclasses of P450s, A-C clades of CCEs, and ABC-A, ABC-B, and ABC-G subclasses of ABC transporters (Pavlidi et al 2013), C. ceratitis activated the epsilon subfamily of GST, CYP6 and CYP12 of P450s, B clade of CCEs (Papanicolaou et al 2016), and P. utilis mainly triggered the delta, epsilon and microsomal subfamilies of GSTs, CYP4, and CYP9 of P450s, C clade of CCEs and ABC-G subclass of ABC transporters (Li et al 2018), but R. pomonella mainly launched CYP4 and CYP6 of P450s (Ragland et al 2015) (Table 3). For the digestive gene family, B. dorsalis (Shen et al 2013) and C. capitata (Silva et al 2006, Nash et al 2019 primarily triggered aminopeptidase, trypsin and serine peptidase digestive genes, but B. oleae, which is a strictly monophagous species, triggered serine protease and nuclease digestive genes to respond to different host secondary chemical environments (Pavlidi et al 2017) (Fig. 1).…”

“…1.Major digestion-related genes reported for selected tephritids based on documented transcriptome data. Bactrocera dorsalis(Shen et al 2013) and Ceratitis capitate(Nash et al 2019) are two polyphagous species. Bactrocera oleae(Pavlidi et al 2017) is a host plant-limited species.…”

Evolution of reproductive isolation in a long-term evolution experiment withDrosophila melanogaster: 30 years of divergent life history selection

“…2010), (3) competitive ability differences between controls and selected individuals in D. melanogaster (Belkina et al . 2018), (4) positive assortative mating preferences (albeit unstable) in D. melanogaster (Nash et al . 2019); and (5) postzygotic reproductive isolation through genetic incompatibilities in Saccharomyces cerevisiae (Dettman et al .…”

“…For example, a number of studies have investigated the importance of local adaptation to distinct nutrition sources for mating assortment. Divergent selection regimes with different nutritional environments result in premating isolation through (1) the evolution of signalling traits and mating preferences in Drosophila serrata , (2) the evolution of symbiotic microbiota in inbred strains of D. melanogaster (Najarro et al 2015;Sharon et al 2010), (3) competitive ability differences between controls and selected individuals in D. melanogaster (Belkina et al 2018), (4) positive assortative mating preferences (albeit unstable) in D. melanogaster (Nash et al 2019); and (5) postzygotic reproductive isolation through genetic incompatibilities in Saccharomyces cerevisiae (Dettman et al 2007) and Neurospora (Dettman et al 2008).…”