Summary -Hobo elements are a family of transposable elements found in Drosophila melanogaster which present a specific deletion-derivative element (Th)
The transposable element hobo has been introduced into the previously empty Drosophila melanogaster strain Hikone so that its dynamics can be followed and it can be compared with the P element. Five transformed lines were followed over 58 generations. The results were highly dependent on the culture temperature, the spread of hobo element being more efficient at 25 degrees C. The multiplication of hobo sequences resulted in a change in the features of these lines in the hobo system of hybrid dysgenesis. The number of hobo elements remained low (two to seven copies) and the insertions always corresponded to complete sequences. Our findings suggest that, despite their genetic similarities, P and hobo elements differ in many aspects, such as mobility and regulation mechanisms.
Eupelmus vuilleti est un ectoparasitoïde primaire et solitaire des stades larvaires de Bruchidae (Callosobruchus maculatus, Bruchidius atrolineatus). En présence d'une forte compétition pour les hôtes sains, E. vuilleti a un comportement ovicide ou larvicide vis-à-vis du Pteromalidae D. basalis en développement (cleptoparasitisme) ; l'expression extrême du cleptoparasitisme conduit les femelles de E. vuilleti à hyperparasiter le dernier stade larvaire (stade L5) de D. basalis. Dans ce travail, on a comparé la variabilité du succès reproducteur des mâles développés en hyperparasitisme à celle des mâles développés sur des hôtes primaires. Le succès reproducteur de ces mâles de 24 h d'âge, analysé en fonction de leur poids, est mesuré par la quantité de spermatozoïdes stockés dans les vésicules séminales, et par la qualité de l'insémination ; cette dernière est définie comme la quantité de spermatozoïdes stockés dans la spermathèque des femelles après un premier accouplement, et par les effectifs de filles engendrées. Les adultes de E. vuilleti dont les larves se sont développées en hyperparasitoïdes sont de taille inférieure à ceux développés sur hôtes primaires ; toutefois, ils possèdent toutes les potentialités requises pour réinvestir une population d'hôtes primaires quand la compétition pour les hôtes devient moins intense.
In 1983, an extensive survey of populations of D. melanogaster was started in a southern French region (Languedoc) in two non-Mendelian systems: the P -M system of transposable elements and the hereditary Rhabdovirus sigma. Unexpectedly fast-evolving phenomena were observed and interesting correlations were noted, giving similar geographical pattern to the region in both systems. For these reasons, the analysis was continued and extended towards the north (Rhone Valley) and the south (Spain). In the P -M system, all the Languedoc populations evolved from 1983 to 1991 towards the Q type which is characteristic of the Rhone Valley populations. In contrast, M ' strains are currently observed in the southernmost French populations and in all Spanish ones, so that there is a clear pattern in their geographical distribution.The frequency of flies infected by the sigma virus dramatically increased from 1983 to 1988 in Languedoc; this increase was clearly correlated with some viral characteristics. But, in northern France, similar characteristics did not trigger any increase in the frequency of infected flies. The data presented here show that the distinctive features of Languedoc extend northwards through the Rhone Valley up to Lyon and disappears southwards before the Spanish border.
GRH 60
Mots clds: ectoparasite gr6gaire, ectoparasite solitaire, quantit6 de nourriture assimil6e, biomasse 61abor6e Key words: gregarious ectoparasite, solitary ectoparasite, quantity of assimilated food, biomass produced R~sum~ Nos m6thodes exp6rimentales permettent l'isolement d'une larve de sexe d6termin6 par h6te de l'ectoparasite gr6gaire Dinarmus vagabundus et du solaitire D. basalis. Des h6tes porteurs de 3/t 8 larves par h6te de D. vagabundus sont aussi isol6s. Dans ces conditions la quantit6 de nourriture disponible est la mSme pour toutes les densit6s larvaires 6tudi6es.Les larves 9 9 61ev6es en solitaire des deux esp6ces assimilent une quantit6 de nourriture significativement sup6rieure ~ celle assimil6e par les o" ~. Ceci conduit h des adultes 9 9 de poids moyen sup6rieur ~ celui des o" cy. Le poids moyen des cy cy et des 9 9 de D. vagabundus diminue significativement aux fortes densit6s larvaires. Uintensit6 de la liaison entre la quantit6 de nourriture assimil6e et la biomasse produite s'affaiblit au fur et ~ mesure que la densit6 larvaire par h6te augmente.Les 9 9 de D. vagabundus de poids moyen (0,42 mg) engendrent deux fois et demi plus de descendants que les 9 9 lilliputiennes (0,20 mg) 6merg6es d'h6tes/l forte densit6 larvaire. Celles de D. basalis (0,65 g) sont moins prolifiques que les 9 9 de D. vagabundus.
The plasticity of the stinging behaviour of female Eupelmidae (Eupelmus vuilleti Crawford, E.orientalis Crawford Hymenoptera: Eupelmidae) was analysed through the interrelationships of a parasitic community living on larval stage of Callosobruchus maculatus Fabricius (Coleoptera: Bruchidae). In traditional African grainstores, Eupelmus females have at their disposal all the larval stages of their host. Their exploitation is revealed by the sting observed on the host caused by the ovipositor of parasitoid females. This stinging behaviour begins immediately on the adult female's emergence, and thereafter there is a daily increase in the number of hosts stung. Stinging activity is linked to the age of the available hosts, but not all of the hosts available are exploited by the two species studied. This absence of total exploitation could indicate a threshold of activity in the stinging acts which could be in part linked to the secretion activity of the poison glands of parasitoid female.In females of E.vuilleti and E.orientalis the stinging act is usually associated with egg-laying. The relationship between stinging and egg-laying is stronger in more advanced larval stages of the host.In the presence of parasitized hosts, females of E.orientalis and E.vuilleti can exhibit hyperparasitism. The majority of larvae (i.e. primary parasitoid) that have been hyperparasitized have been stung and a large number of them are completely inactive. However, E.vuilleti females deposited their eggs in the available space of the pupation chamber of the host. The neonatal larvae from these scattered eggs could exploit any available host without the female having 'prepared the ground' at the time of egg-laying.In Eupelmidae, all this happens as if there were a complementary action between the females and the neonate which could, if necessary, reinforce and/or compensate for the deficiencies in the host exploitation by the female.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.