摘要:

Abstract.A video analysis system was developed to study behavioural circadian rhythms in insects. Technical innovations were performed in image analysis and in the use of robotics. In image analysis, both the automatic detection of the insect and the calculation of several variables (linear and angular speed, locomotor activity, etc.) are carried out in real‐time, which saves time and allows long‐term studies without any intervention of the operator. The displacement of the camera by robotics allows the simultaneous study of many individuals (i.e. sixty individuals for the study of locomotor activity of adult insects, more than 400 individuals for the study of the emergence of adult parasitoids from their host). Four applications of this new device are presented. They deal with circadian rhythms in parasitoid insects: locomotor activity and time variation in locomotory parameters, daily distribution of the emergence and onset of the locomotor activity in adults. The adaptability of the system to several experimental materials and situations is discussed and the interest of the study of behavioural rhythms in the approach of host‐parasitoid associations is empha

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01067.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The braconid parasitoidAsobara tabidaNees attacks larvae of severalDrosophilaspecies in fermenting substrates. Northwestern and central European populations of the parasitoid attack mainlyD.subobscuraCollin. Southern European parasitoids attack mainlyD.melanogasterMeigen. Larvae of this last species can defend themselves against parasitoids by encapsulating the parasitoid egg. Parasitoids from southern European populations are better able to resist encapsulation of their eggs than their northwestern and central European conspecifics. The eggs of southern European parasitoids appear to have a ‘sticky’ egg chorion. As a result of this ‘stickiness’ the eggs become embedded in host tissue where they are not completely covered by the host's blood cells. This leads to, at most, partial encapsulation of the egg. Parasitoid larvae can escape from partially closed c

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01068.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Gypsy moth (Lymantria disparL., Lepidoptera: Lymantriidae) males flying upwind to high concentration pheromone sources had lower ground speeds, shorter crosswind reversal distances and higher turn rates than males flying upwind to low pheromone doses. Casting flight, crosswind flight with no net upwind movement after loss of pheromone contact, developed gradually and was similar in fashion for males initially flying to the three pheromone doses tested; after plume loss, males' flight in the upwind direction decreased from 6 cm turn‐1to nearly 0 cm turn‐1by their fifth turn (crosswind reversal). After plume loss, upwind displacement decreased, crosswind distances and inter‐turn duration increased. Ground speeds tended to increase after plume loss, but airspeeds decreased following loss of 10 and 100 ng plumes and remained constant after loss of 1 ng plumes. Latency to casting wasc. 1 s as measured by cessation of upwind progress and by timing the first reversal leg that was down or crosswind after plume loss. Though these measures of casting were independent of pheromone concentration, they are means that mask the fact that about 40% of males, rather than cast crosswind after loss of the plume, continued to move upwind, with wider and temporally less regular crosswind reversals. Such continued movement upwind is in sharp contrast to previous descriptions of casting flight after loss of odour‐plume contact. In addition, some males engaged in ‘regressive’ casting, moving downwind after bouts of ‘typical’ casting. The value of casting and of the continued upwind flight after plume loss, both possible strategies for recontacting a pheromone plume

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01069.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The chorion of the egg in Callosobruchus maculatus (Coleoptera: Bruchidae) provides protection but also has to allow exchange of respiratory gases. A single opening in the chorion (the egg pore) allows diffusion of gases, and young larvae die if the egg pore is blocked. Comparison of respiration rates using a Gilson respirometer showed an increase in oxygen uptake from the first to the seventh day after the egg was laid; the increase was from 6.8 to 11.2 pl/egg/day in a Brazil strain and from 8.6 to 23.5 pl/egg/day in a Yemen strain. The Yemen strain had double the metabolic rate of Brazil‐strain insects in the larvae, which are exposed to seed toxins, but not in the non‐feeding adults. It is suggested that the higher metabolic rate in the Yemen larvae is related to their ability to develop in seeds that are toxic to the Brazil strain. The egg pore also differed in size and shape between the two strains. The egg pore was cylindrical in the Brazil strain, but shorter and funnel‐shaped with an increased external diameter in the Yemen strain. Calculation showed that the different shape and size of the Yemen egg pore would allow a 2–3‐fold increase in gas conductance compared with the Brazil strain, and this increase was consistent with the enhanced oxygen requirement of the Yemen larvae, which was a little over twice that of the Brazil larvae at 7 days. The anatomy of egg pores in Cmaculatus thus seems to represent a trade‐off between two functions, allowing adequate gas exchange while maintaining the protective function of

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01070.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Feeding cycles and daily locomotory patterns of the German cockroach,Blattella germanicaL. (Dictyoptera: Blattellidae), were correlated with the ovarian development cycle. To meet the nutrient requirement for ovarian development, females increased feeding before forming oothecae. Locomotory activity also increased when females became sexually receptive. All these activities reached a peak just before the formation of oothecae. Ovarian development ceased and locomotion and food consumption decreased during pregnancy. Both mated and virgin females showed similar reproductive cycles, but those of mated females were more precisely timed (intervals between successive oothecae, and pregnancy duration, were 5 ± 0.6 and 17 ± 0.6 days, respectively). However, the intervals between successive oothecae of virgin females were longer and less synchronized. During this longer interval, feeding took place immediately following the discharge of the ootheca, but locomotory activity increased 5 days later when females became sexually receptive. Mated females increased locomotory activities 1 or 2 days before the end of pregnancy, presumably searching for deposition sites for oothecae. Female adults were found to exhibit a daily nocturnal locomotory pattern. However, under the physiological demands of reproduction, the pattern could be changed, for example by increasing activity during photophase when females were sexually receptive. The physiological effects of reproduction override the control of the daily locomotory pattern by its diel cloc

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01071.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Sperm storage duration in the grasshopperEyprepocnemis ploransCharpentier (Orthoptera, Acrididae) was found to be 58.5 days but with a wide between‐female variation (from 26 to 113 days). One copulation was enough to fertilize two to eight egg‐pods and to produce 130 eggs (28–313) and 119 embryos (28–290), on average. Sperm availability, however, decreased progressively with time, so that the majority of females spent a long final period of their lives without laying any pod. Finally, sperm storage duration was positively correlated with clutch size and total production of eggs and

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01072.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Among ten species of neotropical malaria vectors the frequency of egg development by virgin females fed both sugar and blood varied from 23% to 100% and was positively correlated with their mean fecundity. The mean volume of male accessory glands of these same species varied more than 10‐fold and was negatively correlated with population‐ or species‐specific incidence of egg development by virgin females. The accessory glands ofAnopheles nuneztovariGabaldon andAnopheles rangeliGabaldon, Cova Garcia&Lopez are much greater in size than those of the other eight species and are believed to contain secretory materials that stimulate egg production following mating. Insemination did not stimulate egg development inAnopheles albimanusWiedemann whose males possess comparatively small accessory g

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01073.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Adults of the eucalypt nectar fly,Drosophila flavohirtaMalloch (Diptera: Drosophilidae), feed onEucalyptuspollen. Flies of both sexes gather pollen with the proboscis, forming a large mass of pollen on the anterior surface of the extended proboscis. Pollen gathering alternates with quiescent periods when the moistened pollen load is continually vibrated. No pollen was found in the adult gut, and it is suggested that hydration of the pollen causes release of nutrients which are then imbibed. This ‘external digestion’ is reminiscent of that employed by heliconiine butterfl

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01074.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The pheromone‐modulated upwind flight tracks ofGrapholita molesta(Busck) males were video recorded as they approached a point‐source of pheromone in a wind tunnel. The field of view of the video recording was divided longitudinally into 33 cm sections and the flight behaviour of the males in these sections was measured and compared as they approached from 233 cm to 50 cm downwind of the pheromone source. As the males approached the source, their mean ground speeds decreased. The mean values of their track angles increased with respect to due upwind (0d̀), indicating movement more across the wind. These changes resulted mainly from the males decreasing their air speeds as they progressed up the plume toward the source. They did not change the average direction of their steering (course angle). Thus, the increase in track angles resulted from the males allowing themselves to drift more in the wind as they approached the odour source. The males also increased their average rate of counterturning as they approached the source. The net result of all these behavioural changes was a track that slowed and grew narrower, giving the impression that the males were ‘homing‐in’ on the pheromone source as they approached. Causes of these systematic changes in behaviour are considered with respect to the known systematic changes in pheromone plume structure as the distance to the source

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01075.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The effects ofOnchocercainfection onSimulium ornatumMeigen vitellogenesis were investigated. Vitellogenesis is triggered by ingestion of blood and is therefore linked to disease transmission. Vitellin subunits were described for the first time in the Simuliidae. In the British blackfiyS.ornatum, vitellin in the ovaries consists of two subunits, with a large subunit of molecular weight 200 kDa and a small subunit of 68 kDa.Simulium ornatumvitellin was recognized by polyclonal antibodies produced fromAedes aegypti(L.) vitellin. When blackflies were injected withOnchocerca lienalis(Stiles) microfilariae, there was a significant reduction in the amount of vitellin in the ovaries at 24, 34 and 50 h post blood‐feedin

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01076.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY