Life‐history trade‐offs under different larval diets in Drosophila suzukii (Diptera: Drosophilidae)

Abstract

Most larval drosophilids eat the microorganisms that develop in rotting fruit, a relatively protein‐rich resource. By contrast, the spotted‐wing Drosophila suzukii Matsumara (Diptera: Drosophilidae) uniquely develops in ripening fruit, a protein‐poor, carbohydrate‐rich resource. This shift in larval nutritional niche has led to D. suzukii being a significant agricultural pest in the U.S.A. and Europe. Although occupying a new niche may benefit a species by reducing competition, adaptation in host use may generate trade‐offs affecting fitness. To test the hypothesis that fitness trade‐offs will change with adaptation to novel larval diets, D. suzukii larval development on either a diet of a fresh, ripe blueberry (a natural host) or standard artificial Drosophila media (protein‐rich) is compared and the effect of diet on development time from egg to adult, adult body size and male wing spot area, and female fecundity is assessed. Larval development time differs, with larvae on the blueberry emerging as adults earlier than those on the artificial medium, although other fitness measures do not vary between the two diets. In addition, the faster development time on a blueberry does not trade off with body size as expected, although early fecundity is delayed in females that develop on blueberries. Thus, adaptation to a novel larval diet environment does not come at a cost to the ability to develop in protein‐rich resources.

Enhanced yeast feeding following mating facilitates control of the invasive fruit pest Drosophila suzukii

“…Fruit is a poor protein source and development of drosophilid flies is constrained when reared on yeast‐free diets (Loeb & Northrop ; Becher et al . ; Hardin, Kraus & Burrack ), which suggests that D. suzukii larvae likely encounter naturally occurring yeast in host fruit (Jaramillo, Mehlferber & Moore ). Yeast is present in the alimentary canals of adult flies (Hamby et al .…”

Development, Reproductive Output and Population Growth of the Fruit Fly Pest <I>Drosophila suzukii</I> (Diptera: Drosophilidae) on Artificial Diet

“…Inoculating culture media with dry baker's yeast further increased D. suzukii adult and pupal production by one-third. In two other studies, yeast augmentation increased D. suzukii oviposition and pupation by a similar rate (Jaramillo et al 2014;Hardin et al 2015), indicating yeasts are symbiotic and probably provide D. suzukii larvae with the protein that their natural habitats (e.g., ripe or ripening berries) lack (Hamby et al 2012;Hardin et al 2015). However, adding far more than 5 grains (>0.80 mg) of exogenous yeast to the diet could harm cultures if fermentation produces toxic levels of carbon dioxide that sterilize, incapacitate, or kill flies (Markow & O'Grady 2006).…”

“…This result suggests cultures had unlimited food resources for the first month of culture growth. Fruit added to diet media probably provides D. suzukii adults and larvae with additional macronutrients, micronutrients (e.g., phytosterols), and carbohydrate (Jaramillo et al 2014;Hardin et al 2015). Fruit composed 40% of the diet by weight and accounted for a one-third increase in early pupal output.…”

“…A solid food diet for raising laboratory cultures of D. suzukii includes some of the same basic ingredients used in other drosophilid diets, e.g., sugar, fruit, and yeast (Dalton et al 2011;Follett et al 2014;Jaramillo et al 2014;Hardin et al 2015). Although our D. suzukii diet is a very simple formulation, the proper ratio of its ingredients is vital for the fly's balanced nutrition.…”

“…The relatively larger eyes of reared males perhaps occurred because eyes of wild-caught flies lost some of their ocular pigment to leaching into the preservation fluid. In fact, Jaramillo et al (2014) assessed body size for D. suzukii fed a diet containing either fruit or yeast and discovered that mean body size for males and females remained unchanged.…”