摘要:

Abstract.Eggs of a local population ofLocusta migratoriaL. (Orthoptera: Acrididae) collected near Hirosaki (40.5oN) entered diapause when incubated at temperatures between 20 and 35oC. For diapause development the optimum temperature was 10oC. The lower thermal threshold for post‐diapause development was 14.7oC. After chilling at 10oC for 20 days, the rate of hatching varied with incubation temperature, being 0, 61% and 81% at 20, 25 and 30oC, respectively. After chilling for 40 days or more, however, almost all eggs hatched at 20–30oC. Diapause with a reduced intensity seemed to be eliminated easily by a high temperature of 25 or 30oC.When eggs chilled at 10oC for 20 days were kept at 20oC for 7 days or more before incubation at 25oC, almost all eggs maintained diapause. Most eggs chilled at 10oC for three 10 day periods separated by 3 days of warming at 25oC failed to terminate diapause. Daily alternations of 10oC (18 h) and 25oC (6h) decreased the diapause‐terminating effect of chilling. These facts suggest that diapause intensity can be restored if eggs chilled insufficiently are exposed to a moderately high temperature. This reversible change in diapause intensity would play an important role in maintaining diapause before w

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The eggs of the southern green stink bug,Nezara viridula(L.) (Hemiptera: Pentatomidae), are successfully attacked byTrissolcus basalis(Woll.) (Hymenoptera: Scelionidae) and are recognized as hosts by a secretion applied to the egg chorion. This secretion is produced by the follicular cells in the proximal region of the ovariole of the female pentatomid and functions as an adhesive for attaching the eggs to the oviposition substrate. The adhesive and kairomone activity could be partially removed with water. This water extract elicited host recognition behaviour inT. basaliswhen applied to glass beads which stuck together as the extract dried. The adhesive and kairomonal activity was removed completely with acetone since acetone‐washed host eggs were not recognized byT. basalis.Application of the acetone extract to glass beads stimulated ovipositional probes byT. basalis.The adhesive appeared to be composed of a mucopolysaccharide–protein comp

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.To test the hypothesis that the flight activity ofHeliothis armigera(Hiibner) (Lepidoptera: Noctuidae) conforms to the ‘oogenesis‐fiight syndrome’, female moths from India and Malawi were flight tested on nights 2, 4 and 6 after eclosion, using a tethered‐flight technique. Maximum flight activity in the Indian strain occurred on night 2, that of the Malawian strain was not significantly different on the three nights of flight. This difference is explained by the Indian females reaching reproductive maturityc. 48 h before the Malawian females. The existence of a ‘reproduction‐flight syndrome’ was confirmed by flight testing males and females of different maturity status on the fourth night after eclosion. Immature moths flew significantly more than did either mature‐virgin or mature‐mated moths. The inheritance of tethered‐flight activity in a late‐maturing line of MalawianH. armigerawas investigated. Significant estimates of heritability, by offspring on mid‐parent regressions, were obtained for both the total flight time (0.39 æ 0.083) and the longest flight (0.15 ± 0.058). The significance of such tethered‐flight data to noctuid migration in the field is discussed, and the conclusion drawn that the current experimental design does not index migr

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The effects of the blood anticoagulants sodium citrate and sodium heparin on horn fly,Haematobia irritansL., egg production were tested. Sodium citrate was added to freshly collected bovine blood to give final concentrations of 5‐100mM while sodium heparin was used in concentrations of 10–70 USP units/ml blood. Small cages containing five male and ten female newly emerged laboratory‐reared horn flies were maintained for 8–10 days on these blood samples, and mortality and egg production recorded daily. Results showed that as blood citrate concentration was increased, egg production decreased logarithmically. At sodium citrate concentrations of 50 mM and above, severe impacts on egg production and adult horn fly survival occurred. Although no dose‐related response of egg production to increasing heparin concentrations was noted, the 25 USP units heparin/ml blood treatments gave the largest egg production, yielding approximately 28% more eggs than any other treatment. Since citrate is a known chelator of divalent metal cations, the effects of supplemental cation additions to citrated blood were tested for their ability to reverse the egg production decrease seen at 50 mM sodium citrate. Blood samples containing 50mM sodium citrate were supplemented with CaCl2, calcium lactate, CuCl2, cupric acetate, FeCl3, ferric citrate, MgCl2, magnesium acetate, MnCl2, ZnSO4, EGTA or EGTA plus calcium lactate, each at 1 mM except EGTA which was used at 2.5 mM. The magnesium acetate supplement and the combination of calcium lactate plus EGTA resulted in a statistically significant increase in egg production

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00445.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.After mating, female Hessian flies,Mayetiola destructor(Say), sit for several hours before taking flight and exhibiting host‐finding behaviours. Observation of these behaviours indicated that females used both chemical and visual cues to find oviposition sites, and that visual cues from plants consisted of both spectral (colour) and spatial information. Females oriented to and were stimulated to land on targets reflecting wavelengths in the region of 530‐560nm (either alone or in combination with UV) but were inhibited by wavelengths from 400 to 500 nm. This spectral discrimination was probably mediated by photoreceptors located in the medio‐frontal zone of the compound eyes. The spatial patterning of targets also influenced orientation during flight; targets with vertical rather than horizontal contour lengths and a higher density of vertical contour lengths were approached and landed on more frequ

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00446.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Action potentials from olfactory cells in antennae (funiculi) of living tsetse flies,Glossina morsitans morsitansWestwood, were recorded using a surface‐contact technique. Stimuli were the vapours of the seven alkylphenols identified in cattle urine: phenol, 3‐methyl‐, 3‐ethyl‐, 3‐n‐propyl‐, 4‐methyl‐, 4‐ethyl‐, and 4‐n‐propylphenol. In addition, responses to the vapours of 1‐octen‐3‐ol, acetone and dichloromethane were recorded. The phenol‐sensitive cells could be grouped into four subclasses. Subclass, 1, 2 and 3 cells responded to the phenols only, cells of subclass 1 and 2 being activated by these substances, those of subclass 3 inhibited. Cells of subclass 4 were activated to a similar degree by all phenols and by one or more of the other chemicals tested. Subclass 1 cells were strongly activated by the 3‐alkylphenols, whereas subclass 2 cells were most sensitive to 4‐methylphenol. Subclass 3 cells were most strongly inhibited by phenol, and 3‐ and 4‐methylphenol. The results suggest that though individual phenols may be attractive toG. m. morsitans, preference for certain blends of phenols may exist; for example, blends composed of moderate doses of 4‐methylpheno

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00447.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Eight strains of the spider miteTetranychus urticae, originating from different localities in western and central Europe, with latitudes ranging from 40.5 to 60oN, displayed marked differences in the period of chilling at 4oC required for diapause termination under a diapause‐maintaining short‐day photoperiodic regime at 19oC, to which the mites were transferred after the cold period. The higher the latitude from which the strains originated the longer was the period of chilling required for diapause termination, suggesting the presence of a gradient in diapause intensity, diapause being deeper the more northern the origin of the strains.Two strains originating from higher altitudes appeared to have a much deeper diapause than expected from their latitudinal origin. In addition, these two mountain strains showed mutual differences in diapause intensity, notwithstanding the fact that they originated from similar latitudes and altitudes; local climatic conditions probably act as strong selective forces with regard to diapause depth.All strains appeared to be sensitive to photoperiod during the period of diapause development. Diapause was quickly completed by a long‐day photoperiod (LD 17:7 h), but was maintained by a short‐day photoperiod (LD 10:14h). However, even under the latter regime sensitivity to photoperiod gradually diminished and eventually disappeared, thus leading to ‘spontaneous’ termination of diapause. The length of the period of diapause development, as measured by the sensitivity to photoperiod of diapausing mites, varied between strains; it was shorter in the southern strains and longer in the northern strains. The results indicate great variation in diapause intensity between strains, which is probably genetically determined and may have adaptive significance for this widespread species.When young females which had just entered diapause were kept for ever longer periods of time under the diapause inducing short‐day regime at which they had been reared, before being transferred to the cold room, the duration of the period of chilling required for diapause termination was found to decrease proportionally in all three strains tested. These results suggest that intensification of diapause does not occur inT. urticae;diapause intensity seems to be highest at the beginning of diapause and to diminish gradually during diapaus

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00448.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Phonotaxis ofG. bimaculatusfemales is expressed by a course‐consistent, directional approach to a conspecific model calling song emitted alternatingly at sound intensities of 50–90 dB SPL and appears at the age of 6–7 days, the onset of maturation. Mating abolishes phonotaxis after about 1 h. By that time, the content of the attached spermatophore has migrated into the female's sper‐matheca. Removal or emptying of the spermatheca, or severing the ventral nerve cord, fully reinstates phonotaxis, whereas ovariectomy has no effect. We suggest that mechanoreceptors record the expansion of the filled spermatheca and that the inhibitory message is communicated via the ventral nerve cord anteriorly to an unknown control centre in the brain. The loss of phonotaxis is combined with reduced locomotor activity and results in the female no longer being attracted to another calli

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00449.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.An electrical recording technique, combined with simultaneous videofilming, was used to investigate the detailed feeding behaviour ofNilaparvata lugens(Stål) (Homoptera: Delphacidae) on rice. Phases of brief probing, of non‐feeding activities, such as walking and of sustained feeding were observed. Monitoring of electrical signals recorded during long, uninterrupted periods of contact between the insect and its host plant, revealed three pattern classes. Two clearly distinguishable wave‐like patterns represent the hopper sucking from xylem and phloem tissues. The third represents a ‘complex’ of signals believed to be associated with stylet penetration, salivation and sucking activities in non‐vascular tissues of the host plant. This recording method and simple counts of honeydew excretion activity were used to assess the effect on the feeding behaviour ofN. lugensof a sublethal concentration of the nitromethylene heterocycle insecticide 2‐nitromethylene‐l, 3‐thiazinan‐3‐yl‐carbamaldehyde applied to rice. The treatment caused a general reduction in feeding activity. Analysis of the electrical trace revealed that phloem feeding was strongly inhibited. Since these effects were largely reversed on transferring hoppers from treated to untreated hosts, the test compound was considered to have an antifeedant rather than a conventional poisoning effect on the hoppers when appl

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00450.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Carbohydrate changes were measured during the 10‐month adult diapause in the neotropical beetle,Stenotarsus rotundusArrow (Endomychidae, Coleoptera) to test the hypothesis that metabolic suppression causes the accumulation of polyols in the absence of the need for cold tolerance. Glycerol and glucose both accumulate during the first 3 months from June to September, but decline in October, accumulate again in December‐January and finally decline after January and stay low until the adults leave their diapause site in April. Any adaptive significance for this pattern is unknown but its coincidence with previously measured metabolic suppression suggests that glycerol and glucose accumulate as a result of metabolic adjustments during diapause. The relevance of these results to the evolution of polyol accumulation for cryoprotection in temperate insects in discus

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1993.tb00451.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY