摘要:

ABSTRACTThe feeding behaviour of nymphsSchistocerca americana(Drury) was recorded throughout the light phases of the first stadium using a behavioural event recording program on a microcomputer. Most food was ingested on day 4 of the stadium, very little on day 1 and none on day 6, the final day of the stadium. Only 26–45% of the total food intake over the stadium occurred during the dark periods and more food was eaten in the last 4 h of each light period than earlier. Feeding occupied only about 5% of the total time. Variation in food intake was a consequence primarily of changes in the numbers of meals. After day 1, the average meal size did not change significantly. Meal length increased relatively slightly compared with meal size as a consequence of an increase in the proportion of time spent feeding in each meal as meal size increased. Meal size was correlated with the length of the previous interfeed suggesting a volumetric regulation. The distribution of pauses within meals was also consistent with the thesis that meal size is governed by the level of excitation in the central nervous system at the start of the mea

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTDose‐response curves are presented for the diuretic activity in aqueous extracts of brain, retrocerebral complex, and ventral nerve cord ganglia fromAcheta domesticus. Diuretic activity is highest in extracts of brain and corpora cardiaca. In comparison with such extracts, those of the suboesophageal ganglia and thoracic ganglia I‐III produce truncated responses, whilst abdominal ganglia 1–4 show evidence of an inhibition of the diuretic response at high doses. ED50values, obtained from Hill plots, are similar for extracts of brain, corpora cardiaca, corpora allata, and abdominal ganglia, but are 3–4 times higher for extracts of suboesophageal and thoracic ganglia.Separation of aqueous extracts of corpora cardiaca by reversed‐phase HPLC yields a number of fractions which stimulate fluid secretion in isolated tubules. Diuretic activity in these fractions is destroyed by treatment with Pronase E, and on this basis is identified as peptidic. In general, diuretic activity is found in the same RP‐HPLC fractions prepared from aqueous extracts of brain, suboesophageal ganglia, thoracic ganglia I‐III, and abdomina

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTArboreal and terrestrial ants were exposed to 0, 25, 50, 75 and 100 (control)% r.h., at 30oC. Desiccation resistance increased with body size (as dry weight0.55), but not as quickly as expected from the consequences of the surface area and volume relationship (as dry weight0.67). Arboreal ants took 8 times longer to die than terrestrial ants of comparable size. Even after size effects were removed, desiccation resistance differed between various terrestrial species and showed a correlation with foraging patterns.Arboreal and terrestrial ants whose waterproofing epicuticular lipids were removed by chloroform: methanol extraction had equally high water loss rates at 0% r.h. Unextracted arboreal ants had water loss rates half those of unextracted terrestrial ants, suggesting that differences between them were based on differences in epicuticular lipids. The lower water loss rates of arboreal ants contributed significantly to their longer survival under desiccation. Arboreal ants also had greater total rectal pad area than terrestrial ants, suggesting that they may be able to reclaim faecal water more effectively. There were no differences in the minimum viable water content between the two groups of ants. Both had water loss tolerances comparable with those of arthropods adapted to xeric environments. Initial water loss rates could not account for all of the differences in desiccation resistance between arboreal and terrestrial ants. Other adaptations to desiccation stress by arboreal ants are likely.Comparisons of water loss rates and desiccation resistance between arboreal and desert ants suggest that the arboreal habitat is at least as stressful as the desert habitat.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00489.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTLimonin and its five derivatives were evaluated in feeding bioassays for depression effects on feeding, growth and development of the fourth stadiumLeptinotarsa decemlineata(Say) (Coleoptera: Chrysomelidae). Epilimonol and limonin diosphenol were most effective in depression of feeding and growth, with ED50s 10 and 8 μg/cm2. At a dosage of 31.6 μg/cm2, epilimonol, limonin diosphenol and limonin caused both significant feeding reduction and developmental delay, while deoxylimonol, tetrahydrolimonin and limonol were not effective. Mouth‐part coating and antifeedant bioassays show that feeding inhibition at host acceptance level seems to be the primary mode of action of epilimonol and limonin diosphe

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00490.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTIn field‐trapping experiments the unsaturated analogues (E)‐6‐, (E)‐12‐, and (Z)‐12‐tetradecenyl acetate were as attractive to maleYponomeuta rorellusLatr. as the native pheromone component tetradecyl acetate. All four analogues attracted more males than virgin females did, whereas (Z)‐6‐, (E)‐11‐, (Z)‐10‐ and (Z)‐11‐tetradecenyl acetate were essentially non‐attractive. Addition of 1–30% of (Z)‐11‐tetradecenyl acetate to the pheromone tetradecyl acetate reduced the attraction to less than 2%. Flight tunnel experiments withY. rorellusconfirmed the activity of the (E)‐6‐ and (E)‐12‐tetradecenyl acetates and demonstrated the activity of (E)‐7‐tetradecenyl acetate as well. These analogues elicited orientation behaviour, upwind flight and landing at the odour source as frequently as the native pheromone did. Single sensillum recordings from maleY. rorellusshowed two types of cells in most sensilla. A large spike amplitude cell was stimulated by tetradecyl acetate and the unsaturated analogues (E)‐11‐, (E)‐6‐ and (E)‐12‐tetradecenyl acetate, and to a lower extent by the (Z)‐6‐, (Z)‐11‐ and (Z)‐12‐isomers. A cell with medium spike amplitude was stimulated by (Z)‐9‐tetradecenyl and (Z)‐11‐hexadecenyl acetate. Some sensilla contained a third cell firing with a small spike amplitude which was activated by (Z)‐11‐tetradecenol. Thus the tetradecyl acetate receptor was stimulated not only by the behaviourally active analogues, but also by behavioural antagonists. The interaction of (E)‐11‐tetra‐decenyl acetate and tetradecyl acetate with the same antennal receptor cell was also demonstrated inY.cagnagellus. Electrophysiological discrimination between behavioural attractants and antagonists and the role of behavioural antagonists in the i

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00491.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTA classical conditioned response was used to evaluate the learning behaviour of honeybees (Apis melliferaL.) which survived a sublethal dose of permethrin. Treated bees had lower learning response levels than untreated bees for 3 days, but regained normal learning ability on the fourth day after exposure. However, bees trained prior to exposure showed no significant effect of permethrin on their conditioned response.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00492.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTResponses of galeal sensilla of the Colorado potato beetle,Leptinotarsa decemlineataSay (Coleoptera: Chrysomelidae), to leaf sap fromSolanum tuberosumand a number of other solanaceous and non‐solanaceous plants are described. A single cell responds vigorously to expressed sap fromS.tuberosum, ‐and even to ten‐fold dilutions of expressed sap. The response is characterized by a high spike frequency, low phasic activity and a tonic phase which can last for tens of seconds. At 8 s following stimulus application the primary response is typically 50% of its original activity, indicating slow adaptation to the sap stimulus. The primary response varies little among multiple stimulations of single sensilla and among sensilla on the same animal. There is a secondary response to potato leaf sap from one or more cells which have low spike amplitudes. This is usually of much lower frequency than the response from the primary cell, and it is highly variable.The prominent and reproducible single cell response to potato sap may be an important component in signalling the presence of a host plant. This hypothesis is tested using saps from two other species ofSolanumwhich are hosts, and several solanaceous and non‐solanaceous non‐hosts. Responses of galeal sensilla to the three host‐plants tested were qualitatively similar and reproducible while responses to the non‐hosts were highly variable and qualitatively different from responses to host saps. These results are interpreted and discussed in the context of a possible mechanism for chemosensory coding of complex stimuli in the insect/plant relationship.Analysis of the raw electrophysiological data required extensive use of a microcomputer and several programs were developed during the course of this study. The computer analyses are briefly described in the paper and additional information and copies of the programs are available fro

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00493.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTA simple method of recording stereoscopically the behaviour of moths in nocturnal, low‐altitude flight in the field is described. Sample results, showing the flight ofHeliothis armigera(Hiibner) and other noctuids at 2–11 m above a crop of pigeon‐pea in India are presented. Flight trajectories, reconstructed in three dimensions, demonstrated that most of the moths flew close to the horizontal, in straight lines, and that their average air (flight) speed was 5.0 ± 1.9 m s‐1. There was no evidence of mass climbing flight away from

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00494.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTThe amount of the major component of the cuticular sex pheromone, 3, 11‐dimethyl‐2‐nonacosanone, on individual female German cockroaches,Blattella germanica(L.), as a function of age was determined by gas‐liquid‐chromatographic analysis. Accumulation of phermone increased with age in both virgin and mated females. During the first gono‐trophic cycle, the pheromone accumulated most rapidly when oocyte growth rates were maximal (days 5–10), and least rapidly while the female carried an ootheca (days 11–32). Pheromone accumulation was similar in virgin and mated females when the same physiological stages (determined by oocyte maturation) were considered. Inhibition of Juvenile Hormone release, through allatectomy, chemicals (precocene or fluoromevalonate), or through mechanical egg case implants, suppressed or delayed pheromone production and oocyte growth. The Juvenile Hormone analogue ZR512 induced allatectomized or head‐ligated females and females with chemically or mechanically inhibited corpora allata to produce pheromone and enlarge their basal oocytes. Finally, ZR512 applied to intact females stimulated pheromone production in a dose

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1990.tb00495.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY