摘要:

Abstract.Mean supercooling points for a variety of soil and litter arthropods including mites, springtails, a heteropteran and immature spiders from a central Alaskan taiga site ranged from ‐6.3 to ‐28.5°C during autumn. Variation in supercooling ability of five species of cryptostigmatid mites occurred throughout the year with increased cold tolerance in autumn and early winter concomitant with the temperature pattern of the habitat. No correlation between the level of supercooling and water content of the mites was evident. Changes in the frequency distribution of individual supercooling points occurred in autumn, winter, spring and summer samples which were species specific. All arthropods tested were susceptible to freezing, and the mites utilize supercooling to avoid free

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. The life cycle ofSialis lutariain two experimental reaches, one treated with the herbicides dalapon and 2,4‐D (Chemical) and the other subjected to a conventional method of plant control (Hand), of a drainage channel in Essex took about 2 years.2. A maximum density of 815 m‐2was recorded and the density of each year class in both reaches generally decreased exponentially with age.3. At certain times of the year the mean individual weight of each year class increased exponentially with age. Annual production was estimated to be 985 (Hand) and 1171 (Chemical) mg dry weight m‐2, with ratios of annual production to mean standing crop (P: b̄) of 1.6 and 1.8 respectively.4. There was no evidence that the use of herbicides had any discernible effect on the mortality, growth or production ofS.l

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Five species of psyllid occurred on seven species ofSalixat Meade River, Alaska. Studies were made on the two common speciesPsylla pclmeniLöw andP.phlebophyllaeHodkinson. The former feeds on the phanerophy tesSalix pulchra, S.lanata, S.alaxensisandS.glauca, the latter on the chamaephytesS.phlebophyllaandS.reticulata.2. BothP.palmeniandP.phlebophyllaehad a 1‐year life cycle and nymphal development took place on the femaleSalixcatkin. The life cycle was generally closely synchronized with the period of catkin development. However, only a few eggs were laid onS.glauca3. Seasonal perturbation of the host plant by flooding, ice movement and blown sand prevented psyllids breeding in certain areas colonized by the host plant.4. InP.palmenidensities and ‘feeding pressure’, measured as biomass of psyllids per gram of catkin, on the different host plants followed the sequenceS.pulchra>S.lanata>S.alaxensis>S.glauca.InP.phlebophyllaedensities and feeding intensities were similar onS.phlebophyllaandS.reticulataand grazing intensity was comparable withP.palmenionS.pulchra.5. A highly significant negative correlation was found between psyllid density and catkin dry weight inS.pulchra, S.phlebophyllaandS.reticulata, suggesting that psyllid feeding is affecting catkin growth.6. Predation of psyllid nymphs by syrphid larvae was heavy but there was no evidence of parasitism.7. The life history strategies of the five psyllid species are discussed within the context of the constraints imposed by the arctic envir

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. FemaleG.spinigeradults working alone made nests each consisting of a vertical shaft leading to a series of horizontal brood chambers filled with dung brood masses. Oviposition near the tip of the brood mass occurred while the egg cell was being completed over the expanded ovipositor. The shaft above each brood mass was filled with soil excavated from the next brood chamber. A similar response also filled artificial diverticula. An avoidance reaction towards buried dung prevented damage to pre‐existing brood masses.2. Virgin females did not make nests and did not avoid buried dung, but after mating (at about 4 weeks after eclosion) both types of behaviour were released within a few hours.3. The presence of dung was required to initiate but not to maintain nesting behaviour. If dung was removed after oviposition the chamber was filled with soil produced by renewed excavation. Cellulose pulp could substitute for dung in brood mass formation.4. Beetles interchanged between burrows at different stages before oviposition readily repeated all pre‐oviposition behaviour. They appeared to respond to the length of the shaft and of the brood chamber since they extended short shafts and short brood chambers considerably more than those of normal length. After oviposition the beetles continued to make brood masses even under abnormal conditions.5. Tilting the cage through 90° caused beetles before oviposition to re‐orientate their burrowing direction, but tilting just after oviposition caused them to make vertical brood masses. Placing the shaft in a horizontal position towards the end of brood mass formation postponed the termination of this phase.6. Beetles repeatedly excavated shafts and chambers when transferred to new cages. Conversely they repeatedly made brood masses when maintained in preformed plaster‐of‐Paris burrows.7. This nesting behaviour can be described as a reaction chain in which each action generates its own terminating stimulus and initiates the subsequent response. The behaviour before oviposition could be omitted or repeated as required by the environment, but after oviposition there was little response to external interference. These characteristics have direct relevance to the survival of

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00569.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. The workers and queen of the leaf‐cutting antAtta cephalotesfed on the juice of swollen hyphae (staphylae) produced by their cultivated fungus, but neither obtained sufficient energy from this source for their respiratory needs. The number of staphylae eaten by workers increased with worker size but was not enough to satisfy their energy requirements.2. Larvae fed on whole staphylae and staphylae previously chewed by workers, and obtained sufficient energy from this source for respiration and growth. No evidence of feeding on fungus hyphae or of trophallaxis between worker and larvae was found. Larvae preferred staphylae to hyphae when fed them artificially and they gained more weight on the former.3. Worker ants imbibed plant sap during the preparation of plant material for the fungus garden and the uptake of carbohydrate during this process was sufficient to supply their energy needs for approximately 24 h.4. Staphylae were richer in lipid and carbohydrate, and poorer in protein than ant fungal hyphae.5. The number of staphylae produced by the fungus gardens of two small nests was comparable with the observed consumption rate but would provide only about 4% of the nest's respiratory requirements.6. In the light of these findings, a revised view of the role of the fungus in the diet of the ant is discusse

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00570.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Radar observations are reported which demonstrate nocturnal accumulations of insects in the altitude range 30–130 m over some sections of the River Niger.2. It is shown that on occasions when individual insect tracks were resolved, the accumulations were maintained by positive insect flight manoeuvres, and were not the result of passive response to air movement.3. The mechanisms by which the insects might perceive the presence of the river are examined and it is deduced that at least some of the insects were able to detect the river boundaries by a visual or radiation sensing mechanism. It is noted that if the insects were using visual perception, their eyes must have been able to function in the absence of moonlight.4. Evidence is presented which suggests that amongst the insects which contributed to the phenomenon were Ephemeroptera, and also larger insects, the latter becoming concentrated over the river in the course of migratory flight across the area.5. Reasons why the insects accumulated over the river are discussed and it is suggested that the most probable strategies included the formation of mating swarms by some insects, and the use of the river by others as a linear feature to facilitate their orientation. It is also suggested that the insects may have been responding to differences in infra‐red radiation from the river and the bank, or to the warmer, moister air to be expected over the ri

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00571.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Collembola and oribatid mites from windswept mountain ridges at about 2700 m a.s.l. in the Austrian Alps were all killed by freezing, and depend on supercooling to survive low winter temperatures. The CollembolaTetracanthella afurcataHandschin,Xenylla acaudaGisin andIsotomaspp. collected in January had average supercooling points between ‐25 and ‐29°C, and the oribatid mitesFuscozetes fuscipes(Koch) andLepidozetes singularisBerlese of about ‐28 and ‐31°C respectively. The ability to supercool was not increased during storage at ‐5°C, and was generally lower in species collected in March.2. The oribatid mitesFuscozetes intermediusCaroli and Maffia,F. fuscipes, Damaeus diversipilis(Willmann) andL.singulariscontained from 9 to 16 μg glycerol per mg fresh weight after storage at ‐5°C, while no glycerol could be detected in the CollembolaIsotomaspp.,T.afurcataandOnychiurus vontoerneiGisin.3. Activity below 0°C was observed inT.afurcataandO.vontoernei, which had chill‐coma temperatures of ‐7.7 and ‐4.9°C respectively.4. Some specimens ofF.intermediussurvived more than 90 days of anoxia at 0°C,T.afurcataup to 60 days andO.vontoerneiup to 24 days.5. The overwintering biology of Collembola and oribatid mites from the Austrian Alps appears similar to that of Norwegian species, except that those from Austria have slightly lower supercooling points and hi

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00572.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. A series of samples of Homoptera was obtained by fogging the canopy ofLuehea seemanniitrees in tropical forest in the Panama Canal Zone at three different times of the year.2. The peak of abundance occurs around July (at least 11.8 individuals/m2), in the early wet season, at a time when most of the trees in the forest, includingLueheaare producing new leaves.3. Minimum abundance occurs in March (at least 3.5 individuals/m2), in the late dry season.4. The samples obtained are some 35% richer in species per given number of individuals than light trap samples taken simultaneously in a similar forest some 6 km away from the present sampling site.5. The data show that the effect of intensive light trapping on the populations of Homoptera in the forest is virtually negligible.6. For a given sample size the tropical samples are many times richer in species than samples from temperate areas.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00573.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

DISPERSAL CENTRES OF SPHINGIDAE (LEPIDOPTERA) IN THE NEOTROPICAL REGION. By Harald Schreiber.TSETSE FLIES IN NIGERIA: A HANDBOOK FOR JUNIOR CONTROL STAFF. By Howell Davies.INSECTS AND OTHER ARTHROPODS OF MEDICAL IMPORTANCE. By Kenneth G. V. Smith.DISEASES AND PESTS OF ORNAMENTAL PLANTS, 5th edition. By Pascal P. Pirone.NEW ZEALAND INSECT PESTS. Edited by D. N. Ferro.THE LIFE OF THE BUMBLEBEE. By D. V. Alford.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00574.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY