Bracoviruses are domesticated viruses found in parasitic wasp genomes. They are composed of genes of nudiviral origin involved in particle production and proviral segments encoding virulence genes necessary for parasitism success. During particle production, proviral segments are amplified and individually packaged as DNA circles in nucleocapsids. These particles are injected by parasitic waspstogether with their eggs into host larvae. Bracovirus circles of two wasp species were reported toundergo chromosomal integration in parasitized host hemocytes, through a conserved sequence named Host Integration Motif (HIM). Here, we used bulk Illumina sequencing to survey integrations of Cotesia typhae bracovirus circles in the DNA of its host, the maize corn borer ( Sesamia nonagrioides ) seven days after parasitism. First, assembly and annotation of a high-quality genome for C. typhae enabled us to characterize 27 proviral segments clustered in proviral loci. Using these data, we characterized large numbers of chromosomal integrations (from 12 to 85 events per host haploid genome) for all 16 bracovirus circles containing a HIM. Integrations were found in four S. nonagrioides tissues and in the body of a caterpillar in which parasitism had failed. The 12 remaining circles do not integrate but are maintained at high levels in host tissues. Surprisingly, we found that HIM-mediated chromosomal integration has occurred at least six times accidentally in thewasp germline during evolution. Overall, our study furthers our understanding of wasp-host genome interactions and supports HIM-mediated chromosomal integration as a possible mechanism ofhorizontal transfer from wasps to their hosts. Importance Bracoviruses are endogenous domesticated viruses of parasitoid wasps that are injected together with wasp eggs into wasp host larvae during parasitism. Several studies have shown that some DNA circles packaged into bracovirus particles become integrated into host somatic genomes during parasitism, but the phenomenon has never been studied using non-targeted approaches. Here we use bulk Illumina sequencing to systematically characterize and quantify bracovirus circle integrations that occur in four tissues of the Mediterranean corn borer ( Sesamia nonagrioides ) during parasitism by the Cotesia typhae wasp. Our analysis reveals that all circles containing a host integration motif (HIM) integrate at substantial levels (from 12 to 85 integrations per host cell in total) in all tissues while other circles do not integrate. In addition to shedding new light on wasp-bracovirus-host interaction, our study supports HIM-mediated chromosomal integration of bracovirus as a possible source of wasp-to-host horizontal transfer with long term evolutionary consequences.

Nowadays molecular species delimitation methods promote the identification of species boundaries within complex taxonomic groups by adopting innovative species concepts and theories (e.g. branching patterns, coalescence). As some of them can efficiently deal with large single-locus datasets, they could speed up the process of species discovery compared to more time consuming molecular methods, and benefit from the existence of large public datasets; these methods can also particularly favour scientific research and actions dealing with threatened or economically important taxa. In this study we aim to investigate and clarify the status of economically important moths species belonging to the genus Spodoptera (Lepidoptera, Noctuidae), a complex group in which previous phylogenetic analyses and integrative approaches already suggested the possible occurrence of cryptic species and taxonomic ambiguities. In this work, the effectiveness of innovative (and faster) species delimitation approaches to infer putative species boundaries has been successfully tested in Spodoptera, by processing the most comprehensive dataset (in terms of number of species and specimens) ever achieved; results are congruent and reliable, irrespective of the set of parameters and phylogenetic models applied. Our analyses confirm the existence of three potential new species clusters (for S. exigua (Hübner, 1808), S. frugiperda (J.E. Smith, 1797) and S. mauritia (Boisduval, 1833)) and support the synonymy of S. marima (Schaus, 1904) with S. ornithogalli (Guenée, 1852). They also highlight the ambiguity of the status of S. cosmiodes (Walker, 1858) and S. descoinsi Lalanne-Cassou & Silvain, 1994. This case study highlights the interest of molecular species delimitation methods as valuable tools for species discovery and to emphasize taxonomic ambiguities.

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Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the “high dose/refuge” strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the “high dose/refuge” strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseola fusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B . fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B . fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B . fusca to Bt corn must address non-recessive resistance.

Identification and assay of cyanogenic and phenolic compounds in phloem sap of cassava (Manihot esculenta Crantz, Euphorbiaceae) and in honeydew of the cassava mealybug Phenacoccus manihoti Matt. Ferr. (Homoptera, Pseudococcidae) were realised.Cyanogenic glucosides and three flavonoid glycosides (rutin, kaempferol glycoside-1 and kaempferol glycoside-2) were found to be translocated in cassava phloem sap and consumed by the mealybug. Differences in profiles of secondary compounds of phloem sap and honeydew samples, characterised mainly by the appearance of free cyanide and of a free flavonoid, suggest the metabolic processing of at least some of the ingested compounds.The relationship between foliar concentrations of these different compounds and expression of the antibiotic resistance of cassava towards P. manihoti was also investigated in 7 varieties of cassava and in the 'faux-caoutchouc' hybrid. Infestation by mealybug was followed by a clear increase in levels of both rutin and kaempferol glycoside-2, while no modification in cyanide contents was noted. The best rank correlation between antibiotic resistance (measured by the intrinsic rate of increase re) and secondary compounds analyzed is observed with rutin contents of infested plants (p=-0.73; p=0.05). The possible implication of this compound in the biochemical mechanisms accompanying cassava defence reaction to mealybug attack is discussed.

Abstract. Sexual behaviour in most of the noctuid Lepidoptera follows a diel periodicity and is limited to a precise period of either the day or the night. The periodicity and the maturation periods are specifi c as well as the onset of oviposition behaviour. The knowledge of these traits of biology is an essential prerequisite for all the studies in chemical ecology. The periodicity of adult emergence, calling behaviour and oviposition of Busseola fusca (Fuller) was studied under laboratory conditions. Most males emerged before onset of the scotophase whereas most females did so one hour later. The virgin females started to exhibit calling behaviour few hours after emergence and there is no sexual maturation time. The calling behaviour starts the fourth hour after the onset of the scotophase but is lightly delayed for females having emerged the same night as compared to older females. Sexual and oviposition behaviours occur during the dark period. Oviposition started the fi rst night after the mating night, peaked during the second night and then gradually decreased until the fi fth night. The fi rst night of oviposition, females laid eggs during the fi rst three hours and after the 5 th hour of the scotophase with a maximum during the 8 th and 9 th hour. During the second night, oviposition peaked during the second hour and tended to decrease thereafter. Résumé. Chronologie de l'émergence, du comportement d'appel et de l'oviposition chez la mineuse du maïs Busseola fusca (Fuller) (Lepidoptera : Noctuidae). Le comportement sexuel de la plupart des lépidoptères Noctuidae est cyclique et limité à une période bien précise du jour ou de la nuit. Les rythmes et les délais de maturation sexuelle sont propres à chaque espèce. L'initiation du comportement de ponte est aussi une des composantes de l'espèce. La connaissance de ces points de biologie est un préalable indispensable à toutes études d'écologie chimique qui traitent de la reconnaissance du partenaire sexuel et de la plante-hôte. Les périodes d'émergence, du comportement d'appel et de ponte de Busseola fusca (Fuller) ont été étudiées dans des conditions de laboratoire. La plupart des mâles émergent avant le début de nuit et les femelles lors des premières heures. Le comportement d'appel des femelles vierges débute quelques heures après l'émergence et il n'y pas chez B. fusca de délai de maturation sexuelle. La période d'appel commence quatre heures après le début de nuit, et est un peu plus tardive pour les femelles qui viennent d'émerger. L'insecte présente une activité nocturne tant pour l'accouplement que pour la ponte. L'oviposition débute la nuit qui suit celle de l'accouplement et la quantité d'oeufs déposés augmente la deuxième nuit de ponte pour ensuite décroître progressivement jusqu'à la cinquième nuit. La ponte se répartit sur toute la durée de la scotophase avec deux pics : l'un se situe en début de nuit et l'autre dans la seconde moitié de la scotophase.

Many parasitoid species are subjected to strong selective pressures from their host, and their adaptive response may result in the formation of genetically differentiated populations, called host races. When environmental factors and reproduction traits prevent gene flow, host races become distinct species. Such a process has recently been documented within the Cotesia flavipes species complex, all of which are larval parasitoids of moth species whose larvae are stem borers of Poales. A previous study on the African species C. sesamiae, incorporating molecular, ecological and biological data on various samples, showed that a particular population could be considered as a distinct species, because it was specialized at both host (Sesamia nonagrioides) and plant (Typha domingensis) levels, and reproductively isolated from other C. sesamiae. Due to its potential for the biological control of S. nonagrioides, a serious corn pest in Mediterranean countries and even in Iran, we describe here Cotesia typhae Fernandez-Triana sp. n. The new species is characterized on the basis of morphological, molecular, ecological and geographical data, which proved to be useful for future collection and rapid identification of the species within the species complex. Fecundity traits and parasitism success on African and European S. nonagrioides populations, estimated by laboratory studies, are also included.

Abstract. The number and distribution of chemosensilla located on different organs of Busseola fusca (Fuller) (Lepidoptera: Noctuidae) males and females are described based on observations using scanning electron microscopy, selective staining with silver nitrate, and gustatory electrophysiological recording. The antennae and the fi fth tarsomere of the prothoracic legs of both sexes bear chemosensilla: uniporous chaetica and multiporous trichoidea sensilla. However, there is a sexual dimorphism in the number and size of sensilla on these organs. The distal part of the ovipositor has uniporous gustatory chemosensilla of the chaetica type. The involvement of these sensilla in oviposition site selection by B. fusca is discussed. Résumé. Dimorphisme sexuel des sensilles chémoréceptrices des antennes, des tarses et de l'ovipositeur du foreur de graminées africain, Busseola fusca (Fuller) (Lepidoptera: Noctuidae).Le nombre et la distribution des sensilles chémoréceptrices présentes sur les différents organes sensoriels des mâles et femelles de Busseola fusca (Fuller) (Lepidoptera: Noctuidae) ont été étudiés sur la base d'observations en microscopie électronique à balayage, par leur réponse à une coloration sélective au nitrate d'argent et à l'électrophysiologie de contact. Les antennes et le cinquième article des tarses des pattes antérieures des deux sexes possèdent des sensilles chémoréceptrices identifi ées respectivement comme de type chétiforme uni-poreux et comme de type trichoïde multi-poreux. Un dimorphisme sexuel est observé par rapport au nombre et à la taille de ces sensilles. La partie distale de l'ovipositeur possède également des sensilles chémoréceptrices gustatives chétiformes. Le rôle de ces structures chémoréceptrices dans la sélection du site de ponte chez B. fusca est discuté.