摘要:

Abstract.1. Survival of four species of ants,Myrmica rubra, Myrmica scabrinodis, Lasius nigerandLasius flavus, exposed to prolonged inundation and the drinking of brackish water, was experimentally determined.2. In most of the experiments, survival ofLasius flavusworkers was much worse than eitherLasius niger or Myrmica scabrinodis.3. After inundation with brackish water, and drinking of brackish water for more than 3 weeks, survival of workers ofMyrmica rubrawas also more affected than thatof Lasius nigerandMyrmica scabrinodis.4. As a rule, survival of dealated queens after inundation appeared to be better inLasius flavusandLasius niger, but worse inMyrmica rubra, compared with worker survival.5. After surviving inundation, the capacity to produce eggs and workers was only slightly affected in queens ofboth Lusiusspecies.6. The conclusions based on the experimental mortality rates seem to be consistent both with ant species distribution and with frequency of inundation and salt stress in different parts of the coastal plain and surrounding sand‐dunes on the Dutch Wadden island Schiermonnikoo

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. An ‘edge‐effect’, where outlying host plants receive proportionately most attention from insect herbivores, is described from the literature, and from data onAnthochoris cardamines(L.), in northern England.2. Six hypotheses are examined as explanations for the effect inA.curdamines. Four are shown to be refuted by studies on female behaviour and the survival of larvae.3. It is argued that the ‘edge‐effect’ comes about due to two or more aspects of the searching behaviour of females. The effect may be seen as an outcome of behaviour adapted to searching for host plants of

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. The effect of temperature on several aspects of the biology ofDrosophila affinis, D.algonquinandD.athabascawere investigated in order to gain insight as to why these closely related species differ in their spatial and temporal patterns of occurrence.2. No differences exist between the three species in the effect of temperature on egg hatchability.3. Productivities of the three species were measured in a temperature gradient device. These measurements indicated thatD.athabascahas an advantage in productivity overD.affinisat cooler temperatures (below 25°C). At warmer temperatures (above 25°C) the greater productivity ofD.affinismakes it the better species.Drosophila algonquin, likeD.athabasca, was characterized by its productivity curve as a species more adapted to cooler climates.4. The competitive abilities of the three species were measured at 25°C, at 18°C, and in an environment which fluctuated between 18 and 25°C on a daily cycle. Competitive ability was estimated on the basis of the performance of the species in two‐ and three‐species populations.5. In general,D.affinisexhibited its highest competitive ability relative to the other two species at the highest experimental temperature.D.athabascahad its highest competitive ability at the lowest temperature. The competitive ability ofDdgonquinwas intermediate; less than that ofD.affinisbut greater thanD.athabasca.6. The dependence of competitive ability and productivity on temperature is thought to be partly responsible for the differences between the species with respect to their geographic distributions and their spatial and temporal patterns in natural pop

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00652.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. Male and female bagworm larvae develop and pupate at different heights on redcedar trees.2. Habitat segregation by height of male and female bagworms is apparent by the third instar, and results in part from differential movement of male and female larvae on redcedar foliage during their development. Females gradually ascend the crown, whereas males remain at the same height on the tree.3. Parasitism of male bagworm pupae was greater than for female pupae. Pupal parasitism is heaviest in the bottom of redcedar trees, where most male bagworms pupate.4. Several hypotheses are offered concerning the origin and maintenance of differential habitat utilization by male and female bagworms, despite apparently strong selection against males pupating low in the crowns of redcedar.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00653.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. Nesting female beetles righted brood balls (so as to replace the egg or larva in the uppermost position) and repaired damaged balls. This behaviour required the presence of an egg or larva in the ball, or of a short‐lasting material found just after oviposition. The shape of the ball was also a righting stimulus since artificial ellipsoids were stood on end.2. Balls containing dichloromethane extracts ofC.lunarisbrood were righted and repaired. Eggs and larvae of several other Scarabaeidae did not release these responses but were destroyed.3. Righting behaviour was released when brood was absent from the top of the ball. The beetle then crawled vertically downwards and, if it encountered the displaced apex, a novel rolling action followed which automatically turned the ball towards the correct position.4. An opening made in the nest was repaired with soil excavated from the chamber floor.Clunarisadults andAphodius fossorlarvae were attacked if they were encountered in the nes

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00654.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. The seasonal distribution of macrolepidopteran species richness on Finnish deciduous trees vaned from positively skewed (peak in spring) to negatively skewed (peak in autumn).2. The skewness values of species richness had a significant negative correlation (r = ‐0.98) with the duration of the seasonal shoot‐growth period of the tree species.3. Trees which complete their shoot growth early in the season (Quercustype) produce new leaves only during spring, while trees whose shoot growth continues to autumn (Populustype) do so throughout the summer.4. Consequently, there is a difference in the number of available resources in the late summer foliage of different tree species, Trees ceasing leaf production early such as oak (Quercus robur) and bird cherry (Prunus padus) have one major resource type (mature leaves) in late‐season foliage while trees like birches and alders have two Ooung and mature leaves).5. Because young leaves formed late in the season are preferred to mature ones by some species of herbivores and because other species prefer mature leaves at the same time, the species richness ofPopulus‐typetrees is higher later in the season than the species richness ofQuercus‐typeof trees, which have just one type of resource

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00655.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. The parasitization of the larvae ofColeophora alticolella. feeding onJuncus squarrosus, was investigated at a series of altitudes from 15 to 520m above sea‐level in northern England during 1977 and 1978.2. Six species of primary parasitoid and one hyperparasitoid were reared from this host. Five of the primary parasitoids were ectophagous; only two specimens of the endoparasitoid,Gonotypus melanostoma, were reared.3. All of the parasitoid species were recorded at 15 m but fewer at sites of higher altitude. Only one species,Scambus brevicomis, was recorded above 305 m, and none above 395 m. The hyperparasitoid,Tetrastichus endemus, waspresent only at 15 m.4. Percentage parasitization was highest at 15 m; it was reduced from 51% to only 2% between 215 and 305 m in 1978. There was an increase in host density over this altitudinal range.5. Three species,Scambus brevicomis. Elachertus olivaceusandEuderus viridis, accounted for most of the parasitization, but their relative proportions vaned at different altitudes.6. The sex‐ratios of the parasitoids reared fromColeophora alticolellaranged from 3.2% females forScambus brevicomis, which is considered to also use larger hosts, to 99.4% females forElachertus olivaceus, which develops by thelytokous parthenogenesis.7.Euderus viridisandScambus brevicomisstarted to attack theColeophora alticolellalarvae at a later date at 245 m than at 15 m, but attack byElachertus olivacatswas not delayed at the higher s

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00656.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. The larvae ofMantispa uhleriBanks (Neuroptera: Mantispidae) board spiders to await the production of an egg sac containing their obligate developmental food. While aboard the spider, larvae maintain themselves by feeding on spider blood. This parasitic behaviour was investigated by allowing larvae to board sixth instarLycosa rabidaWalckenaer (Araneae: Lycosidae). Larval parasitism has a direct and indirect effect on the developmental physiology of the spider.2. The direct effect, equal in both spider sexes, is an increase in development time and a decrease in adult size.3. The indirect effect on development time and adult size is brought about by the loss of an instar in female spiders only. Parasitized females were mature at nine or ten instars; control females at ten or eleven. Male instar number was not affected; both control and parasitized males were mature at nine or ten instars.4. The net result is that parasitized female spiders are even smaller than would be predicted from the direct effect alone, but actually mature faster than control females. In males there is only the direct effect. The adaptive significance of this sexually dimorphic response is discussed.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00657.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. Observations were made on the biology ofGastrophysu polygoni(L.) (Coleoptera: Chrysomelidae) in cereal fields in southern England in 1977, 1978 and 1979. Adults of the overwintering generation emerged in late April/ May and there were usually two generations during the spring and summer months. In 1979 there was some evidence for at least a partial third generation.2. In the field, the oviposition period was 44 days in the first generation andc. 25 days in the second. Fecundity varied from 586 to 1028 eggs per female and was higher in the first than in the second generation in both 1977 and 1979; in 1978 the reverse was true.3. Every year there were Iarge losses in the numbers within a generation. However, only one parasite was bred from the developmental stages and a pathogen attacking the larvae was found only in 1977.4. In some fields and in some years, harvesting and straw burning operations were carried out when eggs were present on the plants. Harvesting did not result in a significant reduction in the numbers of eggs. Burning reduced the numbers of egg batches. The effect was most severe when the straw was spread over the field prior to burning.5. In the field, significantly more eggs were laid on plants ofPolygonum avicularethan onP.convolvulus. In the laboratory, larval survival was higher and duration of development shorter on these two species than on other Polygonaceae found on the farm.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00658.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.1. The paper describes the population dynamics ofPrays citri(Milliere), relevant to the control of this pest by synthetic pheromone, as well as infestation of lemon trees in various areas and seasons.2. The responses of males to natural and synthetic sex pheromones are compared, and ratios for the degree of attraction of traps compared with the degree of attraction of competing wild females are calculated.3. The ratios obtained with various population densities over two seasons of the pest's activity are presented.4. The data are used in a model simulating control ofPrays citriby male mass trapping.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1982.tb00659.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY