Adaptation to new nutritional environments: larval performance, foraging decisions, and adult oviposition choices in Drosophila suzukii

Abstract

BackgroundUnderstanding how species adapt to new niches is a central issue in evolutionary ecology. Nutrition is vital for the survival of all organisms and impacts species fitness and distribution. While most Drosophila species exploit rotting plant parts, some species have diversified to use ripe fruit, allowing earlier colonization. The decomposition of plant material is facilitated by yeast colonization and proliferation. These yeasts serve as the main protein source for Drosophila larvae. This dynamic rotting process entails changes in the nutritional composition of the food and other properties, and animals feeding on material at different stages of decay are expected to have behavioural and nutritional adaptations.ResultsWe compared larval performance, feeding behaviour and adult oviposition site choice between the ripe fruit colonizer and invasive pest Drosophila suzukii, and a closely-related rotting fruit colonizer, Drosophila biarmipes. Through the manipulation of protein:carbohydrate ratios in artificial diets, we found that D. suzukii larvae perform better at lower protein concentrations and consume less protein rich diets relative to D. biarmipes. For adult oviposition, these species differed in preference for substrate hardness, but not for the substrate nutritional composition.ConclusionsOur findings highlight that rather than being an exclusive specialist on ripe fruit, D. suzukii’s adaptation to use ripening fruit allow it to colonize a wider range of food substrates than D. biarmipes, which is limited to soft foods with higher protein concentrations. Our results underscore the importance of nutritional performance and feeding behaviours in the colonization of new food niches.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-017-0131-2) contains supplementary material, which is available to authorized users.

Nutritional geometry and fitness consequences in Drosophila suzukii, the Spotted‐Wing Drosophila

“…Our oviposition results exhibit a similar pattern to that observed by Silva‐Soares et al. (). In their study, females had the choice of three different isocaloric media (spanning the range of P:C ratios of 1:1 to 1:8) and saw the greatest egg laying (measured over a 6‐h period) in the lowest P:C environment.…”

“…When we did not incorporate the antimicrobial agents in the T− assay, larvae did well in those environments, that is, the high carbohydrate media, in which fungi and bacteria flourished (Tournas & Katsoudas, ). The effect of the microbial decay of fruits results in the rapid decrease in sugars and the corresponding increase in proteins (Silva‐Soares et al., ), a pattern that was potentially inhibited in the T+ assay, but could proceed in the T− assay. These results complement the recent findings of Hardin, Kraus, and Burrack (), Bellutti et al.…”

“…While these results suggest D. suzukii can develop on relatively little dietary protein, this study was potentially limited by the scope of P:C ratio diets tested, as well as by the fact that other differences besides P:C between the fly media and the blueberries could have confounded results. The most comprehensive study of D. suzukii utilizing a nutritional geometry framework has been that of Silva‐Soares, Nogueira‐Alves, Beldade, and Mirth (). Using a wide range of media that was manipulated in P:C and P + C to measure oviposition and offspring development, they found a strong bias toward egg laying in the lowest P:C medias and higher larval survival, faster development rates, larger adult masses, and greater ovariole numbers in individuals that were raised in environments that contained more protein.…”

Interacting with change: Diet mediates how larvae respond to their thermal environment

“…These differences in response to nutrition due to temperature increase also mean that larvae have temperature‐specific nutritional optima, presumably to accommodate metabolic differences caused by the thermal environment. Differences in nutritional optima have been shown previously between species that share food resources to reflect differences in ecological niche (Matavelli et al, ; Silva‐Soares et al, ). Here we show that nutritional optima can also change for a given species due to temperature.…”

“…Even though larvae are constrained to forage on a small area (Medina‐Muñoz & Godoy‐Herrera, ; Stamps, Buechner, Alexander, Davis, & Zuniga, ), different parts of the rotting fruit may vary in their P:C content due to the nature of the rotting process. We know that D. melanogaster larvae switch between foods of different macronutrient composition to achieve their P:C target (Rodrigues et al, ), while other species like Drosophila suzukii and Drosophila biarmipes control their nutrient intake primarily by regulating their feeding rate (Silva‐Soares et al, ). It has also been shown that caterpillars and beetles can change their macronutrient target with increasing temperature (Lee et al, ; Rho & Lee, ).…”