Malausa T. auteur aut IRD Pélissié B. auteur aut IRD Piveteau V. auteur aut IRD Pélissier C. auteur aut IRD Bourguet Denis auteur aut IRD Ponsard S. auteur aut IRD text journalArticle eng text/pdf born digital access Changes in host preferences are thought to be a major Source of genetic divergence between phytophagous insect taxa. In western Europe, two sympatric taxa, O. nubilalis (the European corn borer) and O. scapulalis, feed mainly on maize and hop or mugwort, respectively. These two species may have diverged without geographic isolation after a host shift of ancestral populations onto maize or another cultivated species (e.g. sorghum). A previous study using inbred laboratory strains revealed that the two species differ in their oviposition choices in maize-mugwort tests. We sampled four natural populations in France (two of each taxon) and tested their oviposition behaviour toward four of their main host plant species: maize, sorghum, mugwort and hop. O. nubilalis females showed a very high preference for laying their eggmasses on maize, whereas O. scapulalis females displayed a more balanced range of preferences. O. nubilalis females were attracted slightly to sorghum, suggesting that this plant is an accidental, rather than a regular and ancestral host plant of O. nubilalis. One important result arising from this study is the significant proportion of eggs laid by both Ostrinia species on hop. This may explain why some stands of hop are sometimes not only infested by O. scapulalis but also by O. nubilalis larvae, a situation preventing assortative mating based on microallopatry. Hence, further studies must be conducted to see whether the host preference in the genus Ostrinia might be linked to assortative mating by a mechanism that is not mediated by the host plant. specialized Sympatric speciation Ecological speciation Ostrinia nubilalis Ostrinia scapulalis European corn borer Host race Host preference 076 98 2 193-201 2008 0007-4853 https://www.documentation.ird.fr/hor/fdi:010042786 10.1017/S0007485307005536 0007-4853 [F B010042786] https://www.documentation.ird.fr/hor/fdi:010042786 https://www.documentation.ird.fr/intranet/publi/2008/10/010042786.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2008-11-07 2017-08-23 fdi:010042786 fre