摘要:

Abstract.1. The population densities ofDrosophila obscuraandD. subobscurain mixed deciduous woodland were investigated by multiple recapture techniques, marking flies with micronized fluorescent dusts.2. Approximate densities per 100 m2were as follows: September 1974:D.subobscuramales 5,D.subobscurafemales 31. April 1975:D.obscuramales 1,D.obscurafemales 2;D.subobscuramales 0.3,D.subobscurafemales 1. June 1975:D.subobscuramales 6,D.subobscurafemales 9.3. Actual estimates have been compared using relative estimates derived from a reanalysis of Shorrocks's (1975) data.4. Throughout most of the yearD.subobscurawas numerically dominant, rising to a peak of 750/100 m2in the winter; but in late springD.obscurawas dominant, having reduced winter mortality by diapausing.5.D.obscura's density was comparable with those of its Nearctic relatives;D.subobscura's was considerably higher.6. The effects of previous workers' approximations on the estimation of population parameters have been examined, and possible theoretical consequences have been indicated.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00898.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. Trapping experiments and observations of sexual behaviour were made onCephalcia lariciphilain infested larch forests in Hereford and Worcester and Mid‐Glamorgan in early May 1977.2. The results indicated that virgin females and dichloromethane extract of crushed virgin females were highly attractive to males.3. On 17 May males responded to females throughout the warmest part of the day. First response occurred before 09.00 hours, the last after 17.00 hours and peak activity was from 11.00 to 14.00 hours.4. Mated females became unattractive to males within 10 min after mating. When mated females or males were paired with virgin females there was no evidence of an anti‐attractive pheromone or pheromone mask.5. A few males dispersed out of larch into adjacent spruce forests and were captured in virgin female‐baited traps up to 135 m distant from infested larch. Virgin female‐baited traps at 0–0.5 m from the ground captured over seven times the number of males as traps at 1, 2 or 4 m, supporting visual observations that the preferred flight level for males is very near the ground.6. Horizontal board traps with an acetate surface coated with ‘Stikem Special’ were superior to Pherocon IC, vertical board and gypsy moth traps in that order.7. The observations and results suggest that the best applied uses ofC. lariciphilapheromone would be in survey and detection, and male disrupti

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00899.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. The time‐course of anthesis ofEchium vulgareis described.2. Diel changes in the sugar concentration of the nectar, the quantity of nectar and the quantity of sugar per flower are illustrated forE.vulgareand forSinapis alba.3. These changes are interpreted in terms of (a) the periodicity of secretion and (b) the influence of microclimate and insect visits on post‐secretory changes in the composition and volume of nectar.4. There was hour‐to‐hour and day‐to‐day variation in the species composition and the proportion of workers taking nectar rather than nectar plus pollen among the social bees visitingE.vulgare.5. Honeybee visits toE.vulgarewere more numerous in humid weather, when there was enough nectar per flower for their relatively short tongues to reach, and in an area where the corollas grew shorter than they did elsewhere.6. The significance of changes in the caloric content, volume, concentration, viscosity and sugar composition is discussed from the points of view of insects and

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00900.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. The adult biology of the solitary mud‐waspSceliphron assimileDahlbom was studied in Jamaica.2. Adults were active from sunrise until they finally settled in roosting groups a little before sunset. Nesting took place during an 8.5 h period commencing about 3 h after sunrise but individuals rarely spent>4 h nesting per day, the remainder being spent in resting and feeding.3. Males sought females in all places in the habitat.4. The number of cells per nest was positively correlated to high cell density per unit area but negatively correlated to illuminance.5. The number of pellets used to build a cell, but not cell length, was negatively correlated to the body length of the builder. There is evidence that females that build multiple nests locate them within a few metres of each other.6. Incompletely stored cells were closed with an externally concave lamella of mud at the onset of rain or at 16.00—17.00 hours E.S.T. and never reopened the same day.7. Like other species ofSceliphronstudied in this respectS. assimilecollected spiders belonging to the Argiopidae (particularly), and also mainly to the Thomisidae, Salticidae and Oxyopidae.8. The consequences of the nest architecture on mortality and the method of building on distribution are discussed.9. Protarrhenotoky and proterandry occur and probably influence the sex ratio through differential mortality and fecundity. A suggested interaction between the flight motor and the ovaries could regulate egg product

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00901.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. A 24 h time‐sorting pitfall trap was used to collect Carabidae in a field in north‐east England in 1974, 1976 and 1977.2.Harpalus rufipescomprised 62% of the 5288 adult Carabidae caught. It was nocturnal, with an activity peak after midnight. The male activity pattern lagged behind that of females by about 1 h. The activity peak shifted to earlier in the night during September.3. Activity curves are given for eighteen other common species. Large species were all nocturnal, but a third of the smaller species were active in the day. The numbers caught of twenty‐eight less common species are tabulated and show the same trend. Overall, nearly 60% of all species caught were nocturnal and 20% diurnal; the remainder did not show a distinct pattern of day or night activity.4. A total of eighty‐two larvae ofH.rufipes, Nebria brevicollisandNotiophilus biguttatuswere caught, and showed similar activity patterns to those of the respective adult

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00902.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. The data for dispersal ofDrosophila pseudoobscuraof Dobzhansky&Wright (1943) were re‐examined and an improved description found for them.2. The equation that best described the dispersal ofD.pseudoobscurawas found not to be applicable to the dispersal of five other insect species.3. Eight equations describing the density‐distance relation were fitted to the dispersal data of eight insect species. No equation fitted all the data adequately.4. A general expression was deduced from comparison of the eight equations, and found to fit all species better than any of the special ca

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00903.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Abstract.1. Two usual definitions of host discrimination are presented. The first is ‘the ability of a parasite to distinguish unparasitized from parasitized hosts and to lay eggs in the former’. This definition is not useful and even confusing since it does not include the ability of a parasite to distinguish hosts containing different numbers of parasite eggs and to lay preferably only in those with the lowest numbers.2. The second definition is ‘the ability of a parasite to distribute its eggs in a non‐random, regular way among its hosts’. It is argued that most field data are insufficient to permit any conclusions about host discriminative ability on the basis of this definition. An example is given of an apparent random distribution by parasites that are perfectly able to discriminate.3. Arguments are given for studying the behaviour of the parasite in order to answer the question of host discrimination. Five examples of parasites are presented that would erroneously have been classified as non‐discriminators on the basis of the first definition, since they all superparasitize.4. It is suggested that the meaning of the term ‘host discrimination’ be extended to include the ability of a parasite to distinguish hosts with different

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00904.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Book reviewed in this article:BEETLES IN COLOUR. By Leif Lyneborg.HOW INSECTS LIVE. By Walter M. Blaney.GRASSHOPPERS AND LOCUSTS, A HANDBOOK OF GENERAL ACRIDOLOGY. Volume II: Behaviour, Ecology, Biogeography, Population Dynamics. By Sir Boris Uvarov.KEY FOR THE FIELD IDENTIFICATION OF BRASSICA, POTATO AND SUGAR BEET APHIDS WITH PHOTOGRAPHIC ILLUSTRATIONS. By R. N. B. Prior (text) and J. R. Morrison (illustrations).APICULTURE IN TROPICAL CLIMATES. Full report of the First Conference on Apiculture in Tropical Climates. Edited by Eva Crane.A REVIEW OF BIOLOGICAL CONTROL IN WESTERN AND SOUTHERN EUROPE. Edited by D. J. Greathead.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1978.tb00905.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY