Temporal patterns of emergence, calling behaviour and oviposition period of the maize stem borer, Busseola fusca (Fuller) (Lepidoptera : Noctuidae)

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 specific 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 first night after the mating night, peaked during the second night and then gradually decreased until the fifth night. The first night of oviposition, females laid eggs during the first 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

Quinzième colloque scientifique international sur le café

Le scolyte du café, #Hypothenemus hampei, passe la majeure partie de son cycle à l'intérieur des cerises de café. La phase la plus critique pour ce ravageur est donc la période où les adultes femelles se déplacent à la recherche d'une nouvelle cerise. A l'intersaison, on trouve sur les arbres des cerises sèches abritant une population parfois très importante, et des cerises vertes immatures. Les facteurs abiotiques et physiologiques qui conditionnent la sortie des femelles de ces cerises non récoltées ont été peu étudiés. Trois expérimentations ont été conduites afin d'apprécier les stimuli qui interviennent dans la sortie des cerises par les femelles dites colonisatrices. Le dispositif expérimental a permis d'observer que la sortie des femelles est en relation avec l'insolation. Nous avons également constaté une augmentation de la proportion de femelles colonisatrices sorties en présence de cerises vertes. Ceci confirme l'existence de stimuli olfactifs et/ou visuels qui interviendraient dans le déplacement de #H. hampei vers les cerises vertes. (Résumé d'auteur

Temporal patterns of emergence, calling behaviour and oviposition period of the maize stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae). Ann. Société Entomologique Fr

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

Progression in field infestation is linked with trapping of coffee berry borer, Hypothenemus hampei (Col., Scolytidae)

Phenology of the coffee plant and infestation by coffee berry borer #Hypothenemus hampei$ Ferrari were studied in relation to trapping of adult females in kairomone-baited traps in a coffee plantation in New Caledonia. In a 0.4 ha coffee field, a group of 27 trees located along a transect beginning at an early infestation point was selected. The number of green, red and dry coffee berries, along with the number of larvae, adult males and females per berry was determined monthly from October 1993 to July 1994. Twelve, red multifunnel traps, each baited with a solution of methanol:ethanol (1:1 ratio, a mean solution release rate of 1 g/day) were placed within the coffee field, along the transect, within the selected trees, grouped in four zones named 1-4. Two additional traps were located outside the plantation. The proportion of infested berries increased as berry maturity and harvest date approached, while the infestation rate decreased with distance from the epicentre. Over the 10 months of the study, beetle populations increased and spread from the original infestation point across the different zones, according to distance and availability of berries or appropriate physiological status. Traps near the epicentre caught the largest numbers of beetles. Linear relationship between trap catch and infestation level was demonstrated. Traps placed outside the field approached zero catch. Trap catch was highly influenced by rainfall events, and the highest captures coincided with rapidly declining berry numbers on trees. There are good prospects for management of this insect using traps. (Résumé d'auteur