title: Divergence in behaviour between the European corn borer, Ostrinia nubilalis, and its sibling species Ostrinia scapulalis: adaptation to human harvesting?
abstract: Divergent adaptation to host plant species may be the major mechanism driving speciation and adaptive radiations in phytophagous insects. Host plants can differ intrinsically in a number of attributes, but the role of natural enemies in host plant specialization is often underappreciated. Here, we report behavioural divergence between the European corn borer (ECB, Ostrinia nubilalis) and its sibling species Ostrinia scapulalis, in relation to a major enemy: humans. Harvesting maize imposes selective mortality on Ostrinia larvae: those located above the cut-off line of the stalk face almost certain death. We show that ECB larvae diapause closer to the ground than those of O. scapulalis, which is sympatric but feeds mainly on weeds. The difference in diapause height results from genetically determined differences in geotactic behaviour. ECB larvae descend towards the ground specifically at harvest time, increasing their chances of surviving harvesting by about 50 per cent over O. scapulalis larvae. Natural enemies appear as a major driver of host-plant specialization in this example, stressing the need to consider 'tri-trophic' ecological niches to understand insect diversification. Our results also strongly suggest that geotaxis evolved as a singular instance of behavioural resistance in a major agricultural pest.
authors.affiliation: Centre de Biologie et de Gestion des Populations, UMR INRA-IRD-CIRAD-Montpellier SupAgro, Campus International de Baillarguet, Montferrier-sur-Lez, France. vincent.calcagno@mcgill.ca
authors.forename: Vincent
authors.initials: V
authors.lastname: Calcagno
authors.forename: Vincent
authors.initials: V
authors.lastname: Bonhomme
authors.forename: Yan
authors.initials: Y
authors.lastname: Thomas
authors.forename: Michael C
authors.initials: MC
authors.lastname: Singer
authors.forename: Denis
authors.initials: D
authors.lastname: Bourguet
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001522:Behavior, Animal; D006802:Human Activities; D006801:Humans; D007814:Larva / Q000502:physiology; D009036:Moths / Q000254:growth & development / Q000502:physiology*; D013045:Species Specificity; D003313:Zea mays
references.citation: J Evol Biol. 2010 Feb;23(2):350-61
references.pmid: 20002249
references.citation: Genetics. 2007 Aug;176(4):2343-55
references.pmid: 17603115
references.citation: Evolution. 2010 Apr 1;64(4):921-33
references.pmid: 19817847
references.citation: Science. 2005 Apr 8;308(5719):258-60
references.pmid: 15821092
references.citation: Proc Natl Acad Sci U S A. 2009 Oct 27;106(43):18054-61
references.pmid: 19815508
references.citation: Theor Appl Genet. 2003 Mar;106(5):895-903
references.pmid: 12647065
references.citation: Philos Trans R Soc Lond B Biol Sci. 2002 Apr 29;357(1420):471-92
references.pmid: 12028786
references.citation: Proc Biol Sci. 2000 Jun 22;267(1449):1177-84
references.pmid: 10902683
references.citation: Evolution. 2003 Feb;57(2):261-73
references.pmid: 12683523
references.citation: Nature. 2001 Jun 14;411(6839):857-64
references.pmid: 11459070
references.citation: Mol Ecol. 2007 Oct;16(20):4210-22
references.pmid: 17822415
references.citation: Evolution. 2003 Aug;57(8):1735-46
references.pmid: 14503616
references.citation: Proc Biol Sci. 2004 Oct 22;271(1553):2179-85
references.pmid: 15475339
references.citation: Trends Ecol Evol. 2001 Jul 1;16(7):372-380
references.pmid: 11403870
references.citation: Oecologia. 1995 Sep;104(1):52-60
references.pmid: 28306913
references.citation: J Evol Biol. 2007 Sep;20(5):1720-9
references.pmid: 17714289
references.citation: Evolution. 2010 Apr 1;64(4):881-902
references.pmid: 19895559
references.citation: Nature. 2002 May 23;417(6887):440-3
references.pmid: 12024213