摘要:

Abstract.Quantitative effects of temperature, vapour pressure deficit, host, and larval body size were experimentally determined. A simulation model for dynamic water balance in the Mexican bean beetle,Epilachna varivestisMulsant, is presented and parameters are estimated from laboratory data for water gain/loss equations. The model is based on water loss through the cuticle, spiracles and frass, and water gain through ingestion.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01028.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.This paper presents evidence of the relationship between survival and body water content in the Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae). Results of a simulation model for dynamically describing water balance and survival are compared with experimental data for the Mexican bean beetle feeding on both lima bean and soybean under different variable temperature and moisture regimes.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01029.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Inhibition of peripheral chemoreceptors by micromolar concentrations of alkaloids may account for feeding deterrence. Earlier work showed a reduction in both the proboscis extension response and sensory activity recorded from sugar‐sensitive cells in tarsal D and labellar ‘largest’ hairs when the stimulating solution was sucrose mixed with alkaloids. In the present work a similar behavioural effect was also seen when alkaloids were mixed with pyranose and furanose sugars as well as with water and deuterium oxide. Behavioural deterrence continued after the stimulus was removed. Complete recovery occurred after 120 s. To check against the possibility of a central inhibitory state (CIS) having been established two sets of experiments were run in which quinine was applied to a single tarsus followed by a sucrose post‐test to the contralateral tarsus. In one half of the tests sugar was applied first (S1Q2), and in the other half quinine first (Q1S2). Comparable tests were run with contralateral labellar hairs. No CIS was set up by Q1; however, a central excitatory state (CES) was set up by S1. In order to test (a) whether quinine had different effects on other known or unknown receptors and (b) post‐ingestive effects, volumes imbibed in single drinks of sucrose with and without quinine were compared. Volumes of the mixture imbibed were not significantly different from what was predicted based on the known reduction in sensory

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01030.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The ventral coxal hairplate (cxHPv) of the stick insectCarausius morosusBr. (Phasmida: Bacteriidae) contains two morphologically distinct groups of sensilla designated as group 1 and 2 (Gl, G2). The function of these sensilla during walking was tested by selectively ablating one or both groups on one middle leg in thirty‐four animals. It has previously been shown that ablation of the entire hairplate leads to two kinds of errors: the operated leg swings farther forward and the adjacent caudal leg ends its swing more to the rear relative to the operated leg. Following selective ablation of cxHPv Gl on the middle leg, the first kind of error is more pronounced, indicating that this group contributes more to limiting forward protraction during the swing. Following ablation of cxHPv G2, the second kind of error is more evident, indicating that during stance this group contributes more to the target information influencing the swing end‐point of the adjacent caudal leg. These results are interpreted to reflect the phasic and phasic‐tonic response characteristics of Gl and G2 hairs, respect

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01031.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Feeding behaviour of partially engorgedRhipicephalus appendiculatus(Neumann) (Acari: Ixodidae) on rabbit serum held in capillary tubes and placed over the tick mouthparts was studied using the feeding electrogram technique with simultaneous macro video photography. Correlation of electrical events with fluid movement in the vicinity of the tick's mouthparts and the capillary meniscus, permitted the characterization of an orderly sequence of signals, termed the ‘Feeding Complex’, associated with highest weight gains. This complex consisted of a 3–8 Hz fast‐sucking waveform typically lasting 4–5 min, a sharp drop in potential at salivation, and rest lasting 1 or 2 min where no waveform or fluid movements occur. Very high impedence recordings from within the tick capitulum indicate that the fast‐sucking waveform coincides with bursts of potentials corresponding to contraction of the pharyngeal dilator muscles, whereas during rest a tonic series of spikes signifies that the floor of the salivarium is actively lowered. Feeding electrograms of ticks fed on serum from tick‐resistant rabbits showed significantly fewer feeding complexes. The weight gains achieved by these ticks were reduced correspondingly. This suggests that some of the humoral effectors of immunity have an antifeedant effect on this unusual parasi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01032.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.A preparation is described for intracellular recording from the neur‐opile of the sub‐oesophageal ganglion (SOG) of the locust, while stimulating the labial and maxillary palps with plant material in such a way as to mimic the palpation behaviour which precedes and continues throughout feeding. Twelve neurones responding to simulated palpation were recorded from and stained in the SOG. Axons of three neurones ascended to the brain, six had descending axons and three had all of their processes confined to the suboesophageal ganglion. The major regions of arborization were in the ventrolateral and mediolateral neuropiles of the maxillary and labial neuromeres. All twelve neurones were solely mechanoresponsive. In addition to responding to palpation of one or more of the four palps, five also responded to stimulation of the labrum, one to touching each antenna, and one to mechanical stimulation of each of the six tarsi. In the context of what is known about the role of mechano‐stimulation in the control of feeding, and given their particular patterns of input and arborizations, it is suggested that the neurones may be active during food selection and inge

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01033.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The red firebug,Pyrrhocoris apterus(L.), was shown not to be strictly a monovoltine species in Czechoslovakia. A second generation arises from eggs laid by females emerging between June and the beginning of August. Oviposition takes place before diapause is induced in the females by shortening of photophase. Adults that moult later, enter diapause without having laid eggs.Electrophoretic patterns of haemolymph proteins of adults collected in the field throughout a year showed a characteristic temporal pattern of changes correlated not only with the stages of ovarian development, but also with the progression of diapause and post‐diapause quiescence. The changes mainly concerned vitellogenin and polypeptides of molecular weight 78 and 80 kDa.Vitellogenin was present only in the haemolymph of reproductive females. The polypeptides of 78 and 80 kDa, belonging to the group of storage proteins, accumulated conspicuously in the haemolymph of adults undergoing diapause and post‐diapause quiescence. However, the occurrence of these polypeptides seems not to be connected exclusively with cold, because their titres increased with the length of diapause development, even in diapausing adults reared in the laboratory at a constant 26

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01034.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.Respiratory rates of individual workers ofCamponotus rufipesFabricius (Hymenoptera: Formicidae) were measured at 25d̀C and LD 12:12 h (lights on 06.00 hours), DL 12:12h (lights on 18.00 hours), LL (850 lux) and DD (red light, 20–30 lux), using the micro‐Warburg technique. Worker ants were collected from natural nest during the winter of 1987 in a woodland park in the region of Rio Claro, Sāo Paulo, Brazil. The respiration of ants showed a circadian rhythm with acrophase ranging from 20 h 41 min to O1 h 18 min and from 10 h 32 min to 12 h 22 min at LD and DD, respectively. In constant darkness the rhythmometric variables were similar to those presented by ants kept at LD 12:12 h. Under constant light no circadian rhythm in the respiration rates was found. A reduction in the amplitude was observed, indicating an inhibitory effect of this light regime on the respiration pr

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01035.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The oviposition rate of individual queens ofSolenopsis invictaBuren (Hymenoptera: Formicidae) in relation to their weight and number of queens present in the colony was investigated by direct 2 h observations. There is a strong positive correlation between the weight of a queen and its oviposition rate in both monogyne and polygyne colonies. However, the number of eggs laid per mg queen is higher for moonogyne queens than for polygyne queens. This difference is more evident when the total weight of queens present in a colony is considered. The individual queen oviposition rate is negatively correlated with the number of queens in the colony. In addition, the weight loss per egg laid is significantly greater for polygyne than for monogyne queens, probably due to differences in egg size. These data suggest that oviposition is more efficient in monogyne than in polygyne queens at the individual level; however, at the colony level, polygyne colonies produce significantly more eggs. Comparison of colony level efficiency predicts that polygyne colonies must have at least nine queens to compete reproductively with a mature monogyne queen. Therefore, oligogyny does not appear to be a viable strategy forS.invicata.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01036.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.The Photoperiodic of winged females (alatae) in the black bean aphid,Aphis fabaeScop. (Homopetera: Aphididae), is investigated in detail with emphasis on the interaction of the maternal and embryonic/young larval photoperiodic clocks. Previous work had shown that in uncrowded conditions the induction of gynoparae (winged females that produce sexual females) requires both prenatal and postnatal exposure to long‐night (12 h) Photoperidic cycles: present results show that sole postantal exposure to long nights of any lenght does not induce wing formation in early‐born aphids.When aphids were exposed to experimental light‐dark cycles postanatally only, their daughters developed as alate in long nights and as apterae in short nights: the critical night lenght (CNL) was 11:1 h. Additional prenatal exposure to experimental regimes resulted in a significantly shorter CNL (10.6 h). This difference could be accounted for by the fact that more experimental light‐dark cycles were experienced in the latter case.Apterous aphids transferred from LD 16:8 h to LD 12:12 h as either third‐or fourth‐stadium larvae, or young adults, switched for aptera‐production to alata‐production. The transition form aptera‐ to alata‐production was rather abrupt in third‐stadium transfers but more gradual when transfers occurred as fourth‐stadium larvae and adults. Moreover, s the number of days required for 50% of the aphids to become alata‐producers increased from 7–8 in third‐stadium transfers, to 9–10 a

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb01037.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY