title: Lack of genetic differentiation between contrasted overwintering strategies of a major pest predator Episyrphus balteatus (Diptera: Syrphidae): implications for biocontrol.
abstract: Winter ecology of natural enemies has a great influence on the level and efficiency of biological control at spring. The hoverfly Episyrphus balteatus (DeGeer) (Diptera: Syrphidae) is one of the most important natural predators of crop aphids in Europe. Three different overwintering strategies coexist in this species which makes it a good model in order to study ecologically-based speciation processes. The purpose of this study was to determine whether E. balteatus populations with alternative overwintering strategies are genetically differentiated. To that aim, we developed 12 specific microsatellite markers and evaluated the level of neutral genetic differentiation between E. balteatus field populations that overwinter in the three different ways described in this species (i.e. migration, local overwintering at a pre-imaginal stage, and local overwintering at adult stage). Results showed a lack of neutral genetic differentiation between individuals with different overwintering strategies although there are strong ecological differences between them. All pair-wise FST values are below 0.025 and non-significant, and Bayesian clustering showed K=1 was the most likely number of genetic clusters throughout our sample. The three overwintering strategies form one unique panmictic population. This suggests that all the individuals may have genetic material for the expression of different overwintering phenotypes, and that their commitment in one particular overwintering strategy may depend on environmental and individual factors. Consequently, the prevalence of the different overwintering strategies would be potentially modified by landscape engineering and habitat management which could have major implications for biological control.
authors.affiliation: INRA, UMR 1201 DYNAFOR, Castanet Tolosan, France ; Agrocampus Ouest, UMR 1349 IGEPP, Rennes, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Raymond
authors.forename: Manuel
authors.initials: M
authors.lastname: Plantegenest
authors.forename: Bertrand
authors.initials: B
authors.lastname: Gauffre
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Sarthou
authors.forename: Aude
authors.initials: A
authors.lastname: Vialatte
mesh_terms: D000818:Animals; D001042:Aphids; D004175:Diptera / Q000235:genetics / Q000502:physiology*; D010572:Pest Control, Biological / Q000379:methods*; D012621:Seasons
references.citation: Science. 2005 Oct 21;310(5747):502-4
references.pmid: 16239479
references.citation: Curr Biol. 2009 Dec 29;19(24):2097-101
references.pmid: 19962309
references.citation: Genetics. 2003 Mar;163(3):939-53
references.pmid: 12663534
references.citation: Mol Ecol. 2005 Jul;14(8):2611-20
references.pmid: 15969739
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18589-94
references.pmid: 18006662
references.citation: Evolution. 1999 Dec;53(6):1925-1935
references.pmid: 28565443
references.citation: Mol Ecol. 2012 Jul;21(14):3433-44
references.pmid: 22574833
references.citation: Mol Ecol Resour. 2010 May;10(3):564-7
references.pmid: 21565059
references.citation: Mol Ecol. 2001 Oct;10(10):2361-73
references.pmid: 11703649
references.citation: Genetics. 1992 Jun;131(2):479-91
references.pmid: 1644282
references.citation: PLoS Biol. 2005 Jul;3(7):e245
references.pmid: 16000021
references.citation: Mol Biol Evol. 1996 Mar;13(3):510-24
references.pmid: 8742640
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 16;106 Suppl 1:9955-62
references.pmid: 19528639
references.citation: Mol Ecol. 2005 Jun;14(7):2207-22
references.pmid: 15910338
references.citation: J Exp Biol. 2010 Mar 15;213(6):980-94
references.pmid: 20190123
references.citation: Trends Ecol Evol. 2011 Nov;26(11):561-9
references.pmid: 21862171
references.citation: Proc Biol Sci. 2004 Jul 22;271(1547):1521-8
references.pmid: 15306325
references.citation: Theor Appl Genet. 1996 May;92(7):832-9
references.pmid: 24166548
references.citation: Evolution. 1999 Dec;53(6):1915-1924
references.pmid: 28565451
references.citation: Proc Biol Sci. 2011 Oct 22;278(1721):3074-80
references.pmid: 21389024
references.citation: Genetics. 2000 Jun;155(2):945-59
references.pmid: 10835412
references.citation: Evolution. 1984 Nov;38(6):1358-1370
references.pmid: 28563791