摘要:

AbstractThe effects of ageing and female mated status on the flight potential ofHelicoverpa armigera(Hübner), collected as larvae from a pigeonpea crop in southern India, were investigated using a tethered‐flight technique. In non‐mated moths fed sugar solution, from the first night after adult eclosion, the durations of both total and longest continuous flight per night increased up to night 4 and remained at this level until at least night 6. Ovarian maturation was rapid with 77% of unmated moths having commenced oviposition by the third night. On the basis of field evidence it is likely that most females would be mated by the third or fourth night, provided plants with nectar or sugary exudates were locally available. In successfully‐mated females a 15‐fold decrease in total flight duration and a 28‐fold decrease in longest continuous flight duration was observed in contrast to non‐mated females of similar age. As host plants suitable for adult feeding and oviposition were locally available during the time of feral adult emergence, synchronous pre‐reproductive migration was unlikely to occur in the popu

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00549.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractBoth sexes of the stable fly,Stomoxys calcitransL. (Diptera: Muscidae), have receptors on their mouthparts that mediate blood feeding. The potency ranking of the adenine nucleotides (ATP>ADP>AMP>adenosine) in eliciting feeding and suppressing the NaCl‐sensitive cell may indicate the involvement of a P2‐type receptor. This is supported by the lack of effect on feeding by methyl xanthines. Feeding‐related behavioural and electrophysiological results demonstrate that the potency of CH3‐S‐ATP is not greater than that of ATP. These ATP‐mediated responses are antagonized by ANAPP3. Results support the conclusion that the putative ‘ATP receptor’ involved in stable fly phagostimulation resembles the P2xpurinoceptor

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00550.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractMale tsetse flies, probablyGlossina morsitans morsitansWestw., were video‐recorded in the field as they took off and chased other tsetse flies. Chasers responded (took off) to a target fly at a maximum distance ofc.55 cm, when it subtended c. 1.6oto their eye (–1 foveal ommatidial subtense). Chased targets were always within this range (mean subtense at take‐off = 3.2o) and approaching the chaser. The most significant difference between chased and non‐chased targets was in the rate of approach of the target fly in terms of the increase in its image size immediately before the chaser took off (x̄21os−1), especially as its relative increase (x̄690% s‐1P<0.005). No feature of the target's translational velocity, nor any relationship between that and the image size approached this level of significance. Chasers seemed to ‘slipstream’ their target atc.20 cm directly behind it, perhaps suggesting target identification by speed matching. Chases were apparently abandoned when the target image shrank from covering at least two of the chaser's foveal ommatidia to covering only one. Parallax‐free measurements of flight speeds indicated a preferred, stable mean groundspeed of 4.8±0.1 m s_1(SE), at a mean wing‐beat

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00551.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00552.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractLarvae of the tobacco hornworm mothManduca sextastarved for the first 3 days of the last (fifth) stadium undergo a supernumerary moult. If they are provided with sucrose during the starvation period, they develop into normal pupae although pupation is delayed. The activities of the corpora allata (CA) from normal, starved, and sucrose fed larvae were followed through the fifth stadium with a radiochemical assay for Juvenile Hormone (JH) biosynthesis. An attempt was made to correlate CA‐activity with CA cell number, size, and protein content.In CA of normally fed larvae the rate of JH synthesis declined to undetectable levels by day 4 which was also the time of exposure of the dorsal vessel. In CA of starved larvae, the rate of JH synthesis at first decreased but began to increase on day 3 and reached a peak value by day7, at which time head capsule slippage occurred. In CA of sucrose fed larvae, the rate of biosynthesis declined as in normal larvae but the decline was extended over a longer period. Exposure of the dorsal vessel was delayed in the same manner and occurred on days 7–9. The major JH in all cases was JH‐II.The CA comprise c. 150 cells in the early fifth stadium, and this number remained constant during the fifth stadium in all three feeding regimens. In normal larvae, CA size and protein content increased several‐fold during the stadium whereas in starved and sucrose‐fed larvae they increased slowly and in agreement with the altered timing of developmental events. In none of the groups was the CA activity pattern correlated with morphometric changes of the CA. The rates of JH biosynthesis were not closely correlated with published JH titre curves. Thein vivomechanisms for regulation of JH production remain to be e

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00553.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of age on electroantennogram (EAG) responses were investigated in male and femaleGlossina morsitans morsitansand comparative studies on the effects of starvation and sex on the EAG inG.m. morsitans, G.austeni, G.tachinoidesandG.fuscipes fuscipeswere made. Stimuli were the vapours of l‐octen‐3‐ol, 4‐heptanone, 3‐nonanone and acetone. EAG decreased with age in both sexes ofG.m.morsitans, responses in 5‐day‐old flies already being significantly lower than those in 1‐day‐old flies. InG.m.morsitansandG.tachinoides, EAG responses of males were higher than those of females. InG.austeniandG.f.fuscipes, however, the reverse was found. With increasing starvation EAG sensitivity increased in both sexes ofG.m.morsitansandG.tachinoides.InG.austeniand inG.f.fuscipesno clear effects of starvation were observed. Response spectra of the individual species to the four odour substances did not change with increasing hunger. It is concluded that receptor sensitivity may be modulated depending on the insect's needs. Possible mechanisms of regulation and significance of this modulat

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00554.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe timing of the onset of egglaying in the Hessian fly,Mayetiola destructor(Say), is influenced by several exogenous and endogenous factors. Mated females initiated egglaying 48 h earlier than virgins and laid 3–4 times more eggs before dying. The effects of mating on the onset of egglaying were further modified by several other factors whose effects were measured in hours rather than days. Increases in ambient temperatures experienced by mated females shortened the post‐mating pre‐ovipositional transition phase; however, the effects of temperature were not linear throughout the temperature range. Age of females at the time of mating also influenced the onset of egglaying. Females that mated1, 2 and 3 h after eclosion spent190, 160 and 120 min in the post‐mating transition phase, respectively. Effects of age were also observed when females were mated over the three calling periods that comprise the 3‐day lifespan of the adult female. Linear regressions of transition times on time of mating had similar slopes for first and second day post‐eclosion females but were offset such that first‐day females mated late in the morning had similar transition times to second‐day females mated early in the morning. By the third day post‐eclosion, transition times showed no significant changes when females were mated throughout the calling period. Possible mechanisms underlying the effects of mating, temperature, and female age on post‐mating pre‐oviposition transitio

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00555.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractWingstroke frequency, morphometries and thoracic temperatures of freely foraging bumblebees were examined in the field at ambient temperatures varying from 10 to 29oC. Frequency was strongly correlated with morphometric parameters, particularly wing length, but was not correlated with either ambient or thoracic temperature. Magnitudes and scaling of frequency of foraging bees were comparable to values obtained for bees hovering in a closed chamber. These data indicate that frequency is primarily determined by morphometric characteristics which determine lift requirements and do not support the hypothesis that frequency is varied in response to environmental conditions as a means of in‐flight thermoregulatio

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00556.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe vitellogenic period of gypsy moth ovarian development starts on day 3 of the pupal stage and continues through adulthood. During this period, rapid increases occur in follicle size, protein content, and wet weight of the ovary. Patency is observed on day 3 of the pupal stage.Pre‐vitellogenic follicles are formed in the last larval stadium. Newly formed follicles detach from the germarium on day 4, and increase rapidly to 140 per ovariole at the end of the last larval stadium. The pre‐vitellogenic follicles are uniformly around 50 um in diameter. No vitellogenin is incorporated into the oocytes until the pupal stage.Polyacrylamide gel electrophosesis (PAGE) in the presence of sodium dodecylsulphate (SDS) analysis of male and female haemolymph samples and vitellogenic ovaries demonstrates the presence of two female‐specific subunits of vitellogenin of 180 kD and 160 kD. These proteins are detected only in haemolymph and ovarian extracts of vitellogenic females. The molecular weight of the native protein determined by size exclusion chromatography is approximately 400–420 kD.A highly sensitive double antibody sandwich enzyme‐linked immunosorbent assay (ELISA) was developed to monitor the temporal changes in vitellogenin titre in haemolymph. Vitellogenin production starts on day 2 of the last larval stadium, reaching a maximum level by day 6 of the last larval stadium, and decreasing in the late pupal stage as vitellogenin was internalized into the oocytes. This is the first report of vitellogenin production occurring in the larval stage of a holometabolous insect. The fact that vitellogenin production and uptake occur during different stages of development in the gypsy moth, opens up some interesting questions concerning the underlying regulatory mechanisms controlling eac

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00557.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe wing‐fanning activation response of male Oriental fruit moths (OFM),Grapholita molesta(Busck), in the field to the three‐component pheromone containing the female‐produced ratio of components (Z8‐12:OAc + 6% E8‐12:OAc + 3% Z8‐12:OH) was compared with the response to blends containing 2,10 and 20% E with 3% OH, and the 6% E blend containing 30 and 100% OH. Comparisons were made over three temperature ranges: 15–17, 20–21 and 26–28oC. Both the maximum response distance and male response specificity were significantly altered by changes in odour quality as well as temperature. For blends containing different Z/E ratios the maximum response distance increased significantly with temperature. Response specificity was most pronounced at the 20–21oC range, with males displaying a lower threshold for the natural 6% E ratio, evidenced by the fact that fewer males responded and at closer distances to the source with off‐ratios. At 26–28oC response specificity for the Z/E ratios was much reduced, primarily due to more males activating to off‐ratios. With blends containing different proportions of Z8‐12:OH in the 6% E blend, increasing temperature increased the maximum response distance for all treatments, but in addition increasing the proportion of OH alone from 3% to 30% significantly increased the maximum response distance over the three temperature ranges tested. This increase occurred without affecting the proportion of responders or the distribution of response distances around the mean value. However, with 100% OH added to the blend, whereas male response was high at 20–21oC, the distribution of response distances was significantly more variable than with 3% or 30%, and male response was eliminated or very low at 15–17oC and 26–28oC. Our results support previous studies showing that peak response levels in this species are dependent on male perception of the natural blend of components, and that males have a high degree of specificity for the qualitative properties of the pheromone. However, the present results also extend those of previous flight tunnel tests in which response specificity was most pronounced in the upwind flight phase of the sequence, by sh

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1991.tb00558.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY