Dietary eicosapentaenoic acid and docosahexaenoic acid are linearly retained by common insect crop pests (cabbage looper and bertha armyworm) and alter insect biomass. (26th November 2019)

• Record Type: Journal Article
• Authors: Colombo, Stefanie M.; Shukla, Kruti; Campbell, Lesley G.; Tsimbaliouk, Alina; Arts, Michael T.
• Is Part Of: Physiological entomology. Volume 45:Number 1(2020)
• Page Start: 38
• Page End: 49
• Publication Date: 2019-11-26
• Subjects: Bertha armyworm -- cabbage looper -- docosahexaenoic acid -- eicosapentaenoic acid -- larval insect development -- omega‐3 fatty acids -- terrestrial food webs; Insects -- Physiology -- Periodicals; 571.157
• DOI: 10.1111/phen.12314
• Languages: English
• ISSNs: 0307-6962

Abstract

Abstract: The long‐chain omega‐3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are prevalent in aquatic ecosystems and are not part of the natural diet of herbivorous, terrestrial insects, which generally consume alpha‐linolenic acid (ALA) and linoleic acid (LNA). However, recent advances in genetic engineering have lead to the development of terrestrial crops that express the novel traits of EPA and DHA production. In the present study, we examine the effects of dietary EPA and DHA on the growth, development and fatty acid content of two crop pest insects: bertha armyworm and cabbage looper. Five experimental diets were formulated to include increasing amounts of pure EPA and DHA (in relation to the total diet lipid level), according to the ratios (EPA + DHA relative to a vegetable oil containing ALA and LNA): 0 (control), 0.25 : 0.75 (lowest), 0.5 : 0.5 (low), 0.75 : 0.25 (medium) and 1 : 0 (high). Dietary EPA and DHA had significant effects on development time, mass and fatty acid content in both species. Dietary treatment (interactive with time) had a significant effect on individual mass of both insects, indicating that, over time, EPA and DHA impacted growth. However, insect mass, development and morphology results are not linearly related with increasing dietary EPA and DHA. Both species retained EPA and DHA in adult form, and the body content of EPA and DHA was significantly, positively correlated with EPA and DHA diet treatments in both the bertha armyworm ( r 2 = 91.3%) and cabbage looper ( r 2 = 75.8%). Dietary EPA and DHA could have fitness consequences for these organisms and could be nutritionally transferred to higher consumers. Abstract : We examined the effects of dietary EPA and DHA on growth, development and fatty acid content of two common crop pests. Dietary EPA and DHA significantly affected development time, mass and fatty acid content in cabbage loopers and bertha armyworms and, subsequently, stored EPA and DHA in a positive linear fashion in adult insects. The changes observed in biomass, development time and body nutritional content could have fitness consequences for these organisms.