摘要:

Abstract.Starved females ofAedes communis(DeGeer) had significantly shorter mean lifespans than females with access to one blood meal and/or sugar meals. For the starving females, lifespan was significantly correlated with wing length. This correlation was not found in sugar‐ and/or blood‐fed females. Fructose and sucrose had similar effects on mosquito lifespan. The 25% and 50% (w/w) solutions of each, increased mean lifespans to 37.8 ± 7.2 and 34.9 ± 9.1 days, respectively. A 10% solution, of either sugar, was significantly inferior, mean lifespan 23.2 ± 10.2 days. The initial sugar meal was very important for female longevity. Subsequent meals aided in ovarian development. One sugar meal, one blood meal, and several sugar meals during oogenesis was found to be the optimal diet for the female mosquitoes in this

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01011.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The femoral chordotonal organ of a locust front, middle or hind leg was stimulated mechanically under open‐loop conditions and the forces produced by the muscles moving the tibia were measured. In nearly all cases resistance reflexes were elicited in the inactive animal. However, in rare, but reproducible cases, a positive feedback occurred. In an animal performing active movements the responses were very labile: often no response occurred, sometimes a reaction comparable to the active reaction in stick insects was found, and sometimes resistance reflexes were presen

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01012.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Two forms of mosquitoes in theCulex pipienscomplex,C.p.pallensandC.p.molestus, were compared for the insemination‐dependency of entrained female circadian activity in LD 16:8h. When virgin,Pallensis nocturnal andmolestusis, in addition, diurnal. Insemination and injection of extracts of the male accessory gland affects virgin activity in that nocturnality is strengthened in both mosquitoes, and the diurnal activity ofmolestusis depressed. This was so whether the treatments were intra‐ or interspecific. These findings are compared with those already published for other mosquitoes. A coherent view is proposed that the mosquito, nocturnal/crepuscular, nocturnal and diurnal, or diurnal, has potentially a similar entrained waveform which is affected by insemination in a common way, and by lighting conditions in species specific w

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01013.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The metabolic rates, as expressed by oxygen (O2) consumption, carbon dioxide (CO2) production, and losses in wet and dry weights, were examined for adults of three strains of the red flour beetleTribolium castaneum(Herbst), during exposure to two modified atmospheres (MAs). Exposure of a strain selected for resistance over twenty‐one generations to an atmosphere of 65% CO2, 20% O2and the balance nitrogen (N2), termed a high carbon dioxide concentration atmosphere (HCC) and exposure of an unselected strain to HCC, showed considerable levels of aerobic metabolism during exposure. For the unselected strain water loss and mobilization of energy reserves were rapid and mortality was followed by rapid desiccation. For the HCC‐resistant strain water balance was maintained and energy reserves were utilized more slowly over a prolonged period. Exposure of a strain selected for resistance over twenty‐one generations to a low oxygen concentration atmosphere (LOC) of 0.5% O2in N2, and an unselected strain to LOC, revealed that even at 0.5% O2, metabolism was largely aerobic in both strains. Maintenance of water balance was not a major factor causing mortality of either strain during exposure to LOC. In air, metabolic rates of both the resistant strains were lower than that of the unselected s

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01014.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Mated femaleBrachymeria intermedia(Hymenoptera: Chalcididae) deprived, since emergence, from pupae of their hostLymantria dispar(Lepidoptera: Lymantriidae), accumulated eggs but had a very low rate of hostacceptance. Parasitoids that were host‐deprived after encountering pupae early in life also accumulated eggs, but maintained a high acceptance rate. Thus early exposure to hosts promoted active reproductive behaviour. Total egg production depended on the total number of pupae encountered, indicating thatB.intermediaadjust their egg production to host availability. Hence, inB. intermediaboth the physiological state of the parasitoid (age and egg load) and the informational state (in this case host‐availability and experience) interact to shape oviposition behavi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01015.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.FemaleMicroplitis croceipeswithout previous exposure to host diet, feeding damage or faeces, and with no oviposition experience (i.e. inexperienced) exhibited flight tunnel responses towards extracts of faeces from several diet–host species combinations, excluding artificial diet. Inexperienced females exhibited the following preference order towards faeces fromHeliothis zealarvae fed selected diets: cotton>wild geranium>cowpea>artificial diet, suggesting and adaptation to ‘preferred’ host plants.Females having a preflight experience with a plant‐host complex (PHC) prior to testing exhibited a higher percentage of oriented flights in the wind tunnel than did inexperienced females. OvipositionPer sehad little effect on the flight response of females. The increased flight response after an experience is apparently due to a combination of sensitization and associative learning. In a choice situation, a single experience was insufficient to establish a preference for the PHC experienced; however, repeated experience resulted in preferences, and the degree of preference tended to increase with the number of expe

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01016.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.We compared two models based on Monte Carlo simulations with the spacing patterns of resting adults of the mosquitoCx pipiensL. (formmolestus) (Diptera, Culicidae). The comparison with the first model which assumed a distribution of complete spatial randomness showed that there was a tendency for mosquitoes to repel other mosquitoes which were too close, resulting in high local regularity. The second model took this repulsion into account. A final test of global patchiness using Model 2 indicated that the spacing behaviour ofCx pipienswas not sufficiently described by local regularity only, but also required a gregarious element. This supports the hypothesis that themolestusform ofCx pipiensshows spaced‐out gregariousness in the sense of Kennedy&Crawley (1967

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01017.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Bruchidius atrolineatus(Pic) is a tropical bruchid developing in Vigna unguiculata (Walp) pods. Adults are in reproductive diapause during the dry season. In conditions of 40:25d̀C or 35:25d̀C, diapause is induced when larvae develop in thermophases longer than 14 h, in thermophases shorter than 10 h and in continuous darkness. Thermophases of 12 h cause a reduction of the proportion of diapausing beetles. This proportion also depends on the thermoperiod temperatures. Development at low temperatures (23: 16d̀C, 12: 12 h) induces a high percentage of diapausing beetles. However, at low temperatures, the developmental times of the beetles are long and show important interindividual variability. When larvae develop in decreasing temperatures, small changes in thermoperiod temperatures (35:25d̀C to 3O:2Od̀C) have a strong effect on diapause induction. When larvae develop at low temperatures (25:15d̀C) and then at high temperatures (40:25d̀C), the proportion of diapausing beetles depends on the duration of development at low temperatures. Whatever the developmental conditions, both sexually active and diapausing beetles always emerge from the seeds. This interindividual variability is important in this species which has a wide geographical distribution in

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01018.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Females of the subsocial woodroachCryptocercus punctulatusScudder generally have a single oviposition period during which they produce one to four oöthecae. Monogamous pairs and their recently deposited oöthecae were collected in the field, and measured, weighed and analysed for nitrogen in the laboratory. Females put 9.8 ± 2.4% (mean ± SD) of their dry weight and 11.6 ±0.5% of their body nitrogen into oöthecae. The total nitrogen and dry weight of the brood were positively related to the post‐oviposition total nitrogen and dry weight of the mother. A female's investment, on a per nymph basis, averaged 0.06% of her post‐oviposition dry weight. Females may be able to recover up to 58.7% of the nitrogen invested into a brood by consuming the egg cases after hatch. Overall, there was little variation in the width of head capsules of adults in this species, and this parameter was not significantly different between the sexes. Females were heavier than males (dry weight)(P =0.06). Within pairs, the weights and nitrogen contents of males and females were positively correlated, probably because they feed together in the same log for nearly a year prior to rep

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01019.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Laboratory experiments were carried out to determine the role and characteristics of male scent scales (androconia), located in patches (stigmata) on the forewings ofThymelicus lineola(Ochsenheimer) (Lepidoptera: Hesperiidae).In behavioural tests, there were 30—40% fewer matings of virgin females by males with the stigmata removed or where females had their antennal sensilla covered with nail polish, when compared to sham‐treated controls. These reductions occurred despite a large increase in male courtship activity. No physical contact was observed between male wings and female antennae during mating.A scanning electron microscope study of male wings and female antennae showed that: (1) lysis zones form over time on the androconia and pieces (osmo‐phores) distal to these zones break off; (2) while few of these zones are present at emergence they are numerous in‐day‐old males; (3) during a single episode of courtship and mating approximately two‐thirds of the available osmophores break off, yet the commonly observed courtship between males does not appear to result in osmophore release; and (4) osmophores were never observed on the female antennae.Electroantennogram recordings (EAGs) indicated that: (1) female antennae responded strongly to odours from male forewings but not from other parts of either males or females; (2) female antennae responded more strongly to young field‐collected males than to newly‐emerged or old, field‐collected males; (3) female antennal response to male forewings was reduced if the androconia were scraped off, and was eliminated if the stigmata were removed; (4) male antennae gave weak EAG responses to both male and female forewings.We conclude that males release pheromone via the breakage of osmophores during courtship. We propose that the frequently observed refusals by females of courting males are at least partially dependent on the quantity or quality of male pheromone released, which are in turn correlated with the male's age

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01020.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY