摘要:

AbstractLarvae and pupae of the Australian lycaenid butterfly,Jalmenus evagorasDonovan (Lepidoptera; Lycaenidae), are protected from parasites and predators by attendant ants. In return, the juveniles ofJ. evagorassecrete to the ants a solution containing substantial amounts of sugars and amino acids. Larvae ofJ. evagoraswere reared from hatching until adult eclosion either with or without ants. Experiments were performed to examine whether fifth (final) instar larvae attempt to compensate for the nutrient loss to ants, by consuming more food, digesting food more efficiently, or extending development time. The presence or absence of ants had no effect on the feeding rate, efficiency of digestion or development time of fifth instar larvae. Larvae with ants converted a smaller proportion of ingested food into biomass, and consequently grew less than their counterparts without ants. Thus fifth instar larvae ofJ. evagorasdo not appear to compensate for the nutrient loss to ants. Possible reasons for the failure to compensate are discussed.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01186.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractObservations were made on the relative rates of growth among corpora allata, ovarian follicles and fat bodies in diapausing and reproductiveMusca autumnalisDeGeer. Rates of corpora allata growth were greater in long‐day than in short‐day animals. Topically applied precocene II reduced the size of the corpora allata. Two sequential doses of precocene inhibited vitellogenesis. Topically applied methoprene produced vitellogenesis in short‐day flies and inhibited development of hypertrophied fat body. This work provides evidence that Juvenile Hormone is the primary agent controlling diapause and non‐diapause (vitellogenic) development in the ovaries of fac

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01187.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractCold hardiness was investigated in overwintering field nests of the black carpenter antCamponotus pennsylvanicus(De Geer) in the Commonwealth of Virginia. No active nest thermoregulation was observed: temperatures of galleries, worker bodies, worker clusters, and larval clusters were within 3°C of ambient temperature. Nest temperatures generally fluctuated less rapidly and severely than did ambient temperature; thus, the nest afforded protection from potentially fatal sudden temperature drops. Glycerol, the only polyol cryoprotectant detected, was found in all castes and larvae. Supercooling points were low and ranged from − 17°C in major workers to −22°C in larvae. A second heat release peak, occurring around − 8°C, was seen in all adults, but it was not observed in larvae. This higher temperature peak in adults probably represents the freezing of the gut contents, as adults were found to overwinter with the crop full or partially full. Larvae did not overwinter with liquid food i

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01188.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractExpulsion of the tsetse larva from the uterus of the female is preceded by 1–2 h of rhythmic pulses of haemolymph pressure that can be detected using a barographic technique. At first baseline pressure is maintained and all pulses are positive in relation to baseline. Then, about 1 h before parturition, baseline pressure increases, pulse intensity increases, and the pulses become both positive and negative in relation to baseline. Each pulse correlates with ‘bobbing’ action of the female's proboscis, the only external indication of this internal activity. A single large pressure pulse is observed at parturition, and thereafter the pressure level returns to the original baseline and pulsing action ceases. Around the presumptive time of ovulation, 1–2 h after parturition, another series of pressure pulses is observed. The pulses are the likely consequence of coordinated waves of muscular contraction that are essential preparation for successful parturition and ov

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01189.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA strontium capture method, usingp‐nitrophenyl phosphate as substrate, was used to determine the subcellular localization of (Na++ K+)‐ATPase activity in Malpighian tubules ofLocusta migratoriaL. Ultrastructural studies revealed that (Na++ K+)‐ATPase activity was restricted to the basolateral plasma membranes with little evidence of activity associated with the apical microvilli. In contrast, alkaline phosphatase activity was specifically associated with the apical cell membrane. Biochemical assays of fixed and non‐fixed tubule homogenates were used to evaluate thep‐nitrophenyl phosphate‐strontium procedure for localization of the phosphatase component of (Na++ K+)‐ATPase. No significant potassium‐dependent, ouabain‐sensitivep‐nitrophenyl phosphatase activity was demonstrated in homogenates under conditions necessary for the cytochemical procedure, viz fixation, pH 9.0 and the presence of strontium. The significance of the biochemical results are discussed in relation to the validity of such cytochemical techniques for (Na++ K+)

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01190.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA field study in Zimbabwe ofGlossina pallidipesAusten andG. morsitans morsitansWestwood supported Waage's (1981) hypothesis that the striped pattern of zebras may protect them from being bitten by blood‐sucking flies. In addition, the results suggest that the orientation of the stripes may be crucially important for the unattractiveness of zebras.The relative attractiveness of five different stationary targets (black, white, grey, vertically‐striped and horizontally‐striped; stripe width = 5 cm) were each tested on their own and in pairs of all combinations, with artificial host odour (CO2plus acetone) always present. Electric nets were used to catch flies as they attempted to land on or circle the targets. The results were similar for the two species of tsetse. When tested on their own, grey and vertically‐striped targets caught similar numbers of flies and both caught significantly fewer than black or white targets (c.36% as many). Horizontally‐striped targets caught<10% as many flies as any other single target.Although there was no significant difference between the attractiveness of grey and vertically striped targets when they were presented together, when paired with the other targets, grey was as attractive as black or white, but the vertically‐striped target was significantly less attractive than black or white (P<0.001). In other words, a difference between grey and vertical stripes was found only in their attractiveness in relation to other targets. The horizontally‐striped target, however, always caught the fewest flies, regardless of whether it was presented alone or alongside a

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01191.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractDiapause larvae of the European corn borer (Ostrinia nubilalis(Hubn.)) and the related Mediterranean noctuidSesamia creticaLed. possess sufficient supercooling ability to avoid freezing over their normal environmental temperature ranges. In progressive chilling experiments (10 days acclimation at each 5° step in the temperature range from 15 to −5°C), mean supercooling points (measured at a cooling rate of 0.1°C min−1) were lowered from −20.4°C at 15°C to −24.0°C at 5°C (lower lethal temperatures:c.−28°C) inO.nubilalis, compared with −15.0 to −17.2°C (lower lethal temperatures: −15 to −17°C respectively) inS.cretica.Concentrations of glycerol and trehalose determined by gas chromatography of whole body extracts were consistently higher in the former than in the latter species at both 15 and 5°C, and may be responsible for the deeper supercooling inO.nubilalislarvae. Acclimation to 5°C increased glycerol levels inO. nubilalisextracts compared with 15°C, and this was enhanced in larvae exposed for a further 10 days at each of 0 and −5°C (glycerol being 438μmol ml−1body water). Haemolymph glycerol concentrations showed a similar pattern to whole body extracts in this species. Fat body glycogen was reduced during low temperature acclimation in both species. Body water contents did not change with acclimation inO.nubilalis, whilstS.cretica, containing significantly more water, lostc.7% during acclimation from 15 to 5°C. Haemolymph osmolalities increased during acclimation, especially inOstrinialarvae, probably as a result of the accumulation of cryoprotectants. The majority ofO.nubilalislarvae survived freezing under the conditions of the cooling experiments, whilst larvae ofS.creticadid not, thereby confirming an elemen

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01192.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractDuring long post‐feeding periods, adult tephritid flies (and apparently other non‐blood feeding Diptera and even Hymenoptera) engage in behaviour consisting of oral extrusion and aeration of liquid droplets of varying size (‘bubbling’), proboscis pumping, and occasional deposition of regurgitate on the substrate that is followed by subsequent re‐ingestion. Unlike evaporative cooling, which occurs in some insects when heat‐stressed, these regurgitation behaviours take place regularly at moderate temperatures. To our knowledge, the significance of these behaviours has not been studied. We suggest that through bubbling behaviour, fully gorgedRhagoletis pomonella(Walsh) (Diptera: Tephritidae) flies eliminate excess water by evaporation to concentrate nutrients suspended in dilute solution, and release crop volume to allow resumption of fluid feeding or minimize the water load while foraging for other resources. Fly weights were measured continuously during pre‐ and post‐feeding periods and in relation to occurrence of regurgitation behaviours. Fly weight losses during pre‐feeding were an order of magnitude lower than post‐feeding weight losses when flies exposed regurgitated liquid crop contents to air. During a bout of droplet extrusions, lasting on average 23 min, weight loss averaged 66% of the weight of liquid ingested by a fly in the preceding meal. Fly weight loss while bubbling was significantly correlated with duration of bubbling, temperature and relative humidity during post‐feeding, and initial fly weight (adj.R2= 0.95). Fly age, volume of liquid ingested and rate of pre‐feeding weight loss did not significantly improve predicted weight loss through bubbling. Findings are discussed in relation to other behaviours adopted by fluid‐feeding insects

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01193.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe respiration rates ofNotonomus gravis(Chaudoir) andN.philippi(Newman) (Coleoptera: Carabidae) were measured at temperatures between 10°C and 45°C. Mature males of both species had higher respiration rates than mature females. There was no difference between the rates of teneral male and female beetles at 30°C. The difference in respiration rates between the sexes is attributed to the maternal behaviour, and decreased surface activity, of mature femal

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01194.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractAdults ofPyrrhocoris apterus(L.) (Heteroptera: Pyrrhocoridae) reared at 26°C had a considerably lower supercooling point (SCP) in diapause‐inducing (LD 12:12 h) than in diapause‐inhibiting (LD 18:6 h) photoperiodic regimes. Exposure of the insects to diapause‐inducing acclimation conditions (LD 8:16 h and a temperature of 20°C during photophase and 5°C during scotophase) for 2–3 weeks had very little effect on the SCP, irrespective of the rearing photoperiod. Allatectomized adults kept continuously at LD 18:6 h and 26°C had high SCP similar to intact or sham‐operated insects. In contrast to non‐allatectomized insects, the SCP of allatectomized insects decreased after an exposure of from 2 to 3 weeks to diapause‐inducing acclimation conditions (see above) almost to the level found in the intact diapausing insects. The relationship between the decrease of SCP and ‘diapause syndrome’ (de Wild

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01195.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY