摘要:

Abstract.The genetic basis of variation in local searching behaviour in the house fly,Musca domesticaL., was examined by estimating the heritability of locomotory parameters using parent—offspring regressions. Pathways of adult flies were videotaped for 3 min after ingestion of a 1 μl drop of 0.25 M sucrose in a 75 cm diameter circular arena with minimal external cues. Locomotory variables computed from digitized walking pathways, including locomotory rate, turning rates per unit of distance and time, turn bias, number of stops, and stop duration, were significantly heritable, but heritabilities (additive genetic variance ÷ total phenotypic variance) was generally low (<0.25). Phenotypic variance in search parameters increased with time since ingestion of the sucrose drop, but heritabilities were highest when only the first 30 s of the searching bout were examined, and declined as longer periods were considered. Significant genetic correlations among search parameters suggest that many of these characters are influenced pleiotropically by the same genes or closely linked genes. However, some aspects of local search were inherited independently (e.g. stop duration and locomotory rate). The independence of controlling mechanisms was supported by observed differences between genetic and environmental correlations. This genetic independence could enhance the likelihood of appropriate population responses to temporally or spatially changing selective for

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01039.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.That variation in the water and nutrient content of plant tissues affects allelochemical toxicity to insects is well established. However, little is known about how these dietary constituents influence allelochemical deterrency. In vertebrates, deterrency of particular allelochemicals increases with dietary water, and decreases with an increase in dietary nutrients. We determined if these findings were relevant to phytophagous insects through an experimental design that allowed us to vary independently the content of water (70–90% fresh mass, fm, with nutrient level at 10% fm) and nutrients (10–30% fm with water level at 70% or 80% fm) in an artificial diet through use of alphacel, a non‐nutritive cellulose fibre. We examined the effect of these dietary manipulations on allelochemical deterrency by comparing larval feeding responses of two noctuid species, the oligophagousAnticarsia gemmatalisHübner and the polyphagousSpodoptera frugiperda(J. E. Smith), to a control diet and an allelochemical‐treated diet in two consecutive, no‐choice tests. These tests were restricted to 3 min to minimize post‐ingestive influences. From an initial twelve compounds tested, all but two were excluded for the following reasons: (i) failure to elicit an intermediate level of deterrency at<1% fm (i.e. albizziin, amygdalin, hordenine, ouabain, pipecolic acid, salicin, sinigrin and umbelliferone); (ii) an apparently rapid toxic effect (nicotine hydrogen tartrate); and (iii) adsorption to alphacel (quinine hydrochloride), which may have reduced deterrency. The deterrency of caffeine and linamarin increased with dietary water but was unaffected by nutrient content for both species. The similar results for an alkaloid and a cyanogenic glycoside, with two species differing considerably in feeding habits, suggest that dietary water is likely to influence the defensive efficacy of a broader range of deterrent allelochemicals to a variety of plant‐f

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01040.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Vibrational alarm communication was studied in the New World, damp‐wood termiteZootermopsis nevadensis(Isoptera: Termopsidae). Workers and soldiers react to disturbance such as sudden bright light or air currents by drumming their heads against the substratum. This drumming has been described as alarm signalling; its functional significance and perception by the nest mates, however, remained unclear. In the present study we analysed spectral and temporal properties and absolute amplitudes of the vibrational signals and used behavioural responses of the termites to determine the thresholds of the sense of vibration and to find out if and how the termites discriminate the conspecific alarm signals from the background noise.The drumming signals are trains of pulses of vibrations of the substratum with a pulse repetition rate of about 20 Hz. The carrier frequency depends on the substratum; in the nests studied it was in the range 1–3 kHz. The highest vibrational amplitudes measured close to the signal emitters are usually about 10m/s2(acceleration, RMS). The threshold of the behavioural response is about 1m/s2over a wide range of frequencies (10 Hz to 5 kHz), indicating that the termites can detect these signals as vibrations of the substratum. The animals respond preferentially to temporal patterns similar those of the natural signals; temporal rather than spectral cues seem to be used for signal discriminat

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01041.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The time‐course of behavioural phase change was investigated in nymphs ofSchistocerca gregaria, using logistic regression analysis of behaviour recorded in a standard assay. Gregarization occurred very rapidly. Solitary‐reared nymphs became markedly gregarious in behaviour within 1‐4h of being placed in a crowd. These insects re‐solitarized equally quickly if removed from the crowd. Crowd‐reared locusts also solitarized within l‐4h, but this effect was not complete. Results indicate that, while behavioural gregarization is maximal within a few hours of crowding, solitarization is a two‐stage process, changing rapidly at first, then more slowly as a function of the period of prev

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01042.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.When the spermathecal muscle of a virgin femaleChelymorpha alternansBoheman (Coleoptera: Chrysomelidae) was cut, the number of spermatozoa transferred in a single mating to the spermatheca and the spermathecal duct was not affected, but their distribution differed. Cutting the spermathecal muscle also reduced egg fertility. Eggs from females with a cut muscle showed a lower average percentage fertilization. Longer delays in oviposition after removal of the spermathecal muscle were associated with higher proportions of infertile eggs.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01043.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Investigations were undertaken into the mechanisms controlling regulation of salt intake in fifth‐instar nymphs ofLocusta migratoriaL. Initially, the pattern of feeding was recorded for 24 h in locusts fed a chemically‐defined food either with or without salt. Differences were apparent from the first meal, with smaller meals being eaten more frequently on the salt‐free food over the next 8h. As a result, total food intake over the first 8h was similar on the two foods. By 24 h, however, intake of the salt‐free food was considerably reduced and the rate of prefeeding rejections was high. Next, following a period of pretreatment (24 or 48 h) on one of these two foods, responses were recorded to glass‐fibre discs impregnated with salts, artificial foods differing in salt content, and wheat germ. Haemolymph amino acid titres were also recorded in locusts feedingad libitumon salt‐free or salt‐containing food to test the ‘metabolic bottleneck’ hypothesis for explaining rejection of a salt‐free food after a period of feeding on it. Finally, the role of learning was investigated in experiments in which distinctive plant odours and flavours were paired with foods lacking or containing salt. Results across all the experiments indicate that regulation of mineral intake in locust nymphs involves a number of mechanisms, including modulation of locomotory behaviour, innate taste responses and learning. Additionally, there was evidence of a sex differen

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01044.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.During pupal development,Tenebrio molitorL. show regular periods of rhythmic muscular contractions and associated body movements. These periods of activity last 2.5‐5.8 min and are more frequent in newly ecdysed pupae (c.3h‐1). They become less frequent (c.1.5 h‐1) when the basal metabolism reaches its lowest level. In the pharate adult stage the clear pattern of muscular activity disappears.Muscular activity is temperature‐dependent and is commonly absent below 20d̀C. Muscular activity did not disturb the cyclic output of CO2, which is characteristic of metamorphosis. The heart shows characteristic periods (1–3 min) of activity during pupal development. The frequency of these heart pulsation periods depends on metabolic rate. Heart pumping was correlated mostly with muscular contractions. Therefore we suggest that the main physiological function of muscular activity is to support c

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01045.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The effects of variation in diet temperature, mouthpart deployment and the addition of bicarbonate to a saline‐ATP diet were investigated for their effects on amount ingested and diet destination in femaleAedes aegypti(L.). Mouthpart deployment was achieved by having the insects feed through a membrane, or from a free‐liquid surface with mouthparts intact, or with the fascicle separated from the labial groove.Under the ‘feeding through membrane’ protocol, a 6‐fold increase in the percentage ofAedesfeeding on ATP‐diets was recorded at 37d̀C compared with 21d̀C. Bicarbonate (9.5 or 19 mM) induced a 3‐fold increase in numbers feeding at both 21d̀C and 37d̀C. Neither diet temperature nor bicarbonate content appeared to affect meal size. The pH of all diets was adjusted to 7.0. Diet was directed primarily to the midgut for all diets tested under this regimen, with the exception of the saline‐ATP‐19 mM NaHC03at 37d̀C which caused the diet to be directed primarily to the crop.Under the ‘feeding without membrane through feeding tube’ protocol, females showed little control over diet destination. FemaleAedes aegyptiexhibited no strong response to ATP when the mouthparts were immersed in 21d̀C diets in feeding tubes and few of these insects ingested large meals. The addition of bicarbonate to the ATP diets did not enhance feeding

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01046.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Young larvae of the praying mantis,Tenodera sinensisSaussure, were placed on an off‐centre island surrounded by a round arena with six black bars painted on a white inner wall. In this situation, it was shown that the horizontal peering movements of the head often seen in mantids are in fact used to measure distances; motion parallax may be involved in this process. Aimed jumps that followed peering were taken to be the distinct result of an absolute distance measurement. Specific visual deprivation such as painting over of certain parts of the eye with opaque black varnish or degeneration of the fovea with sulforhodamine showed that: absolute evaluation of distance is only possible with two fully intact eyes; the peering mechanism is under visual control; and visual experience has a long‐term effect on distance measurement involving peering moveme

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1994.tb01047.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY