9 research outputs found
Facultative Hyperparasitism: Extreme Survival Behaviour of the Primary Solitary Ectoparasitoid, Dinarmus basalis
This study investigated the egg-laying behaviour of ectoparsitoid, Dinarmus basalis Rondani (Hymenoptera: Pteromalidae), females when faced with a prolonged deprivation of suitable hosts leading to extreme ‘oviposition pressure’. The egg-laying behaviour of virgin D. basalis females was tested with Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) hosts previously parasitized by the conspecific females in which the developing larvae had reached the last larval instar (L5) or pupae. The hyperparasitism did not prevent the occurrence of superparasitism, but only one D. basalis egg from a hyperparasitized D. basalis L5 larvae reached the adult stage due to the solitary behaviour of the D. basalis larvae. Under these experimental conditions, 60.78% of the D. basalis adults emerging from larvae were miniaturized due to the depletion of host resources
Importance de l'association de clones d'hévéas dans l'amélioration de la production du caoutchouc en plantations industrielles au Gabon
Rythmes d\textquoterightactivité locomotrice chez deux insectes parasitoïdes sympatriques : Eupelmus orientalis et Eupelmus vuilleti (Hyménoptère, Eupelmidae)
Rythmes d'activité locomotrice chez deux insectes parasitoïdes sympatriques : Eupelmus orientalis et Eupelmus vuilleti (Hyménoptère, Eupelmidae).
With an automatic image analysis device, we studied the temporal distribution of the locomotor activity of E. orientalis and E. vuilleti during 24 h, and over several days to know whether the activity rhythms of these two Eupelmidae play a role in their competitive interactions. The analysis of locomotor activity rhythms of E. orientalis and E. vuilleti shows that the locomotor activity of both species presents daily cyclic variations. These two Eupelmidae have similar activity rhythms. Displacements of these parasitoids essentially take place during the photophase. But the activity of E. vuilleti is earlier, because the individuals of this species start their activity on average 4 to 5 h earlier than those of E. orientalis. E. vuilleti begins its displacements several hours before the onset of lighting, whereas E. orientalis is active only in the presence of the light. This shift of starting activity is thus a factor allowing these concurrent species to minimize their interactions during the cohabitation period in traditional granaries after the harvests of cowpea
Rythmes d\textquoterightactivité locomotrice chez deux insectes parasitoïdes sympatriques : Eupelmus orientalis et Eupelmus vuilleti (Hyménoptère, Eupelmidae)
Rythmes d'activité locomotrice chez deux insectes parasitoïdes sympatriques : <i>Eupelmus orientalis</i> et <i>Eupelmus vuilleti</i> (Hyménoptère Eupelmidae)
Resistance in cowpea cultivars to Bruchidius atrolineatus (PIC) (Coleoptera: Chrysomelidae: Bruchinae)
Circadian Rhythms Differ between Sexes and Closely Related Species of Nasonia Wasps
<p>Activity rhythms in 24 h light-dark cycles, constant darkness, and constant light conditions were analyzed in four different Nasonia species for each sex separately. Besides similarities, clear differences are evident among and within Nasonia species as well as between sexes. In all species, activity in a light-dark cycle is concentrated in the photophase, typical for diurnal organisms. Contrary to most diurnal insect species so far studied, Nasonia follows Aschoff's rule by displaying long (>24 h) internal rhythms in constant darkness but short (</p>