Loss of lipid synthesis as an evolutionary consequence of a parasitic lifestyle

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 107; no. 19; pp. 8677 - 8682
• Main Authors: Visser, Bertanne, Le Lann, Cécile, den Blanken, Frank J, Harvey, Jeffrey A, van Alphen, Jacques J.M, Ellers, Jacintha
• Format: Journal Article Web Resource
• Language: English
• Published: United States National Academy of Sciences 11.05.2010; National Acad Sciences; Proceedings of the National Academy of Sciences
• Subjects: Animals; Biodiversity and Ecology; Biological Evolution; Biological Sciences; Data processing; Environmental Sciences; Evolution; Feeding Behavior - physiology; Female; Genotype & phenotype; Host-parasite interactions; Hymenoptera; Insect larvae; Insects; Life sciences; Lifestyle; Lipids; Lipids - biosynthesis; Lipogenesis; Lipogenesis - physiology; Negative selection; Parasite hosts; Parasites; Parasites - physiology; Parasitism; Parasitoids; Phenotypic traits; Phylogenetics; Phylogeny; Quantitative Trait, Heritable; Sciences du vivant; Wasps - physiology; Zoologie; Zoology; environmental compensation; parasitoids; fat reserves; coevolution; host manipulation
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1001744107

Evolutionary loss of traits can result from negative selection on a specific phenotype, or if the trait is selectively neutral, because the phenotype associated with the trait has become redundant. Even essential traits may be lost, however, if the resulting phenotypic deficiencies can be compensated for by the environment or a symbiotic partner. Here we demonstrate that loss of an essential me-tabolic trait in parasitic wasps has evolved through environmental compensation. We tested 24 species for the ability to synthesize lipids de novo and collected additional data from the literature. We found the majority of adult parasitoid species to be incapable of synthesizing lipids, and phylogenetic analyses showed that the evolution of lack of lipogenesis is concurrent with that of parasitism in insects. Exploitive host manipulation, in which the host is forced to synthesize lipids to the benefit of the parasitoid, presumably facilitates loss of lipogenesis through environmental compensation. Lipogenesis re-evolved in a small number of parasitoid species, particularly host generalists. The wide range of host species in which generalists are able to develop may impede effective host manipulation and could have resulted in regaining of lipogenic ability in generalist parasitoids. As trait loss through environmental compensation is unnoticed at the phenotypic level, it may be more common than currently anticipated, especially in species involved in intricate symbiotic relationships with other species.