摘要:

ABSTRACT.1Hoplothrips pedicularius(Haliday) (Thysanoptera: Phlaeothripidae), a tubuliferan thrips in which males possess greatly enlarged forelegs, lives in colonies onStereumfungus.2Females oviposit onto communal egg masses, and males fight by grasping and stabbing with their forelegs in territorial defence of oviposition areas. Prolonged escalated fights occur between males who are of similar size.3Larger males usually win fights and become dominant at the oviposition area. Dominant males secure 80% of matings, and mate most frequently during oviposition periods, with an ovipositing female.4Smaller, subordinate males avoid fights and attempt to 'sneak’copulations. However, they occasionally challenge the dominant male. Challenges tend to follow copulations by the subordinate male and occur more frequently between males who are of similar size.5Subordinate males who eventually leave the oviposition area are larger than those who remain, have frequently challenged the dominant male, and have more frequently been stabbed.6Sexual dimorphism in thrips is associated with gregariousness, claustral habitats, female‐biased sex ratios, and male winglessness. In thrips genera in which males exhibit foreleg armature, males are larger relative to females. The ecological circumstances promoting sexual dimorphism and male fighting in spatially‐structured populations are disc

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00286.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1The phytoseiid predatorAmblyseius potentillae(Garman) responded to volatile kairomones emitted from leaves infested by the two‐spotted spider mite (Tetranychus urticaeKoch), the apple rust mite (Aculus schlechtendali(Nalepa)) or the thripsFrankliniella pallida(Uzel), only when the predators had been reared on a carotenoid‐free diet. In contrastA.potentillaeresponded to the European red spider mite (Panonychus ulmi(Koch)) both when the predators had been reared on a carotenoid‐containing and a carotenoid‐free diet.2Carotenoid‐deficient predators did not respond to odour emitted from a host plant that was infested by larvae of the fruit‐tree leaf roller (Adoxophyes orana(F.v.R)), a carotenoid‐containing phytophage, that cannot be preyed upon byA.potentillae.3Carotenoids are indispensable for diapause induction inA.potentillae.Hence, carotenoid‐deficient predators can increase their fitness by feeding from a carotenoid source. This may explain the response of carotenoid‐deficient predators to the kairomones of the two‐spotted spider mite,F.pallidaand the apple rust mite (all containing ingestible carotenoids). As the fruit‐tree leaf roller cannot serve as prey and thus as a carotenoid source, it makes sense that the predators lacking carotenoids do not respond to the kairomone of this phytophagous insect.4Two‐choice experiments in a Y‐tube olfactometer showed that the kairomone preference ofA.potentillaehas a hierarchical structure: the kairomone of the European red spider mite is the most preferred one, followed by that of apple rust mite, whereas the kairomone of the two‐spotted spider mite is the lea

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00287.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Emergence of cabbage root fly,Delia radicum(L.), from overwintering populations of puparia collected from twenty‐one sites in south‐west Lancashire, was extremely variable.2The patterns of emergence indicated that there were two extreme biotypes, one with early‐ and the other with late‐emerging flies. There was also evidence of an intermediate biotype, tending more to early than to late emergence.3This gradient of biotypes, or clinal divergence, was maintained by populations breeding at different times and by females mating close to their sites of emergence. Non‐dispersive females then perpetuated their genotype within their own locality.4The time of emergence was not obviously associated with the type of host‐crop on which larvae had developed.5The late‐emerging biotype was most prevalent around Halsall. The minimum distance between populations of the late‐ and the early‐emerging biotypes was 16 km. 20 km south‐east from Halsall only half of the fly population was early‐emerging, possibly a result of a displacement of the Halsall biotype by the prevailing NW wind.6Regional‐based forecasts will need to take into account the emergence characteristics of the populations to predict the peak periods of cabbage root fly activity adequately in south‐west Lancashire and other areas where

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00288.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Habitat segregation in four species of tiger beetles,Cicindela cancellataDejean,C.cardoniFleutians,C.minutaOlivier andC.sumatrensisHerbst in a river bank ecosystem was studied in dry and wet seasons.2The four species segregated distinctly along the river beds into separate habitats, with occasional overlapping in both the seasons.3Among the habitat characteristics considered, vegetation, soil moisture and available prey‐size were found to be important in species segregation.4D2‐analysis showed that the habitat preferences ofC.cardoniandC.cancellatawere closer to that ofC.sumatrensis.The habitat ofC.minutawas distinctly separated.5There was a positive correlation between the mandible length of each tiger beetle species and the length of prey captured.6Variance in mandible length within species was related to prey‐length distribution pattern and to variance in hab

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00289.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1New data from Australia support previous suggestions that the Ichneumonidae as a whole is not more species‐rich in the tropics than the group is in temperate regions.2Part of the overall lack of increase in tropical species‐richness results from an absence of large groups whose sawfly hosts are not present.3In comparison with temperate faunas, a larger proportion of tropical ichneumonids are generalists, exploit pupae/prepupae, or have long ovipositors, corroborating predictions made by hypotheses advanced to explain the anomalous tropical diversity of ichneumonids.4Two large groups of pupal/prepupal parasitoids (Pimplinae and Mesostenini) are more speciose in equatorial areas.5Diurnal lepidopterous larval parasitoids, and specialist lepidopterous pupal/prepupal parasitoids are scarcer in the tropics than one might expect, but nocturnal lepidopterous larval parasitoids show an increased species‐richness in the tropics. It is suggested that this may be a result of a larger proportion of the suitable host larvae being nocturnally a

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00290.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Field trials were conducted on populations of two sympatic species of the waterbugNotonecta(Hemiptera: Heteroptera), to examine their natural diet using the electrophoretic method of gut contents analysis.2Fingerprint esterase bands were identified from thirty‐three potential aquatic prey types; gut contents of different instars of both species ofNotonectafrom the field were analysed.3The level of prey identification possible ranged from 73% in fifth instarN.glaucaL. to 100% in third instarN.viridisDelcourt.4Type A errors, where no prey remains were detected from a full gut, were found in only 3% of the specimens analysed.5Data on gut states, the number of prey types per gut and details of aquatic prey found in the diet of different instars of field‐collectedNotonectaare presented.6These results are compared with previous data on notonectid diets, and the relative merits of different methods of diet analysis are discus

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00291.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Directional movement by foraging honey bees (Apis melliferaL.) was studied on several flower arrays. The most frequent move among equidistant flower stalks was straight ahead from stalk to stalk with frequencies decreasing for increasing turn angles. Turns to the left were about equal in frequency to turns to the right.2Bees maintained directionality when moving from flower stalks that had been rotated 90° counterclockwise while the bee was on the stalk (no difference between moves from rotated stalks and unrotated controls). Thus, directionality is maintained by the bee and is not an artefact of flower distribution.3Bees also maintained directionality when the entire array was rotated around the flower stalk the bee was on. Thus, bees use an external cue to orientate in a given direction rather than fixing on an inflorescence within the flower array.4Bees foraging on very different flower arrays differed in patterns of directionality and in distances flown between flower stalks. Therefore, even though bees maintain directionality using external cues, flower distribution can nevertheless influence flight patterns

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00292.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Spider mites (Tetranychus urticaeKoch) given a choice between a cotton plant previously damaged by mites and an undamaged control preferentially moved to the control plant.2This host‐choice behaviour was seen in adult female mites but not in immatures.3Adult females were not found to be significantly more fecund on control plants than on previously damaged plants, but the duration of this choice experiment precluded full assessment of effects on fecundity.4Mites responded very quickly, choosing previously undamaged plants without contacting or feeding on the test plants. This suggests that an olfactory response to a chemical substance(s) is involve

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00293.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Cold hardiness as measured by supercooling ability in the active stages of the grain aphidSitobion avenae(F.) decreased progressively with maturation.2Aphids showed no acclimation response when maintained at low temperatures.3Starvation did not improve supercooling ability.4In a single exposure, surface moisture caused inoculation above the inherent supercooling point in a small proportion of a population.5Field populations show a seasonal change in supercooling ability, which is at a maximum in summer and a minimum in late winter.6It is concluded that the act of feeding on healthy plant tissue may confer extensive supercooling ability.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00294.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACT.1Polistes biglumis bimaculatus(G. in Furcroy) (Hymenoptera: Vespidae), a high mountain species, was studied in the Alps. Adaptations of this species to the severe climate and reduced nesting season include nesting characteristics, social organization and division of labour, and caste succession.2Foundress association occurs only in the late pre‐emergence period and is not the same as that seen in low altitude species.3The foundress females continue to forage even in the post‐emergence period and workers and reproductive (males and females) emerge almost contemporaneou

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1986.tb00295.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY