摘要:

Abstract.1Six categories of immature and five categories of mature colonies are described and their developmental relationships suggested.2Mature brood destroyed by the workers became numerous in 46.4% of the immature colonies. Most of these formed unsuccessful colonies (36.9%) producing few or no queens. The remaining 9.5% recovered to form successful colonies.3Successful colonies either reared queens only (mean 356 queens), or queens (mean 1461) and males (mean 254) in their large cells.4The number of small cells in mature colonies correlated with the number of cells built by the founder queen.5The greater the number of large cells in a mature colony the greater were the chances that a larger proportion of these cells would be used to rear adults.6The number of small and large cells are correlated in mature successful colonies.7Queen activity and quality are important factors in the control of colony size and success.8Selective destruction of male sealed brood in the large cells is linked to worker, rather than queen, control.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00966.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The feeding patterns of specialized (Heliconiusbutterflies) and generalized (the grasshopper,Osmilia flavolineata) herbivores on leaf age classes and species of neotropical vines in the genusPassifloraare compared by offering them leaf discs in choice experiments.2Heliconius larvae selected young meristematic leaves over medium aged and mature leaves ofPassiflora auriculataon which to feed.3Adults ofO. flavolineataconsumed more young leaves ofP. pittierifrom an array of different ages of leaf tissue, but showed no preference for young over mature leaves ofP. tetrastylusorP. data.4In choice tests conducted with medium aged leaves of four species ofPassiflora, O. flavolineataselected P. tetrastylus overP. pittieriandP. vitifolia, which were consumed more thanP. alata.5P. alata, which was avoided byO. flavolineatain feeding trials, was the only abundantPassiflorain neotropical habitats where generalized herbivores (grasshoppers and katydids) were common.6Our results suggest thatPassifloraspecies in forest habitats where some generalized herbivores are rare have fewer chemical defences, but retain physical defences (tough leaves and hooked trichomes) rendering them unpalatable to specialized herbivores like the larvae ofHeliconiusbutterflies.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00967.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The feeding behaviour of the two TyphlocybinaeEmpoasca decipiensPaoli andEupteryx atropunctataGoetze and the nature of the damage caused toVicia fabaL. were investigated.2Sections with styletsin situ, i.e. within the plant, were obtained.Eupteryx atropunctatasucked mainly from the palisade parenchyma of the leaf, while several generations ofEmpoasca decipienscould also live from the stem parenchyma and pierced into phloem if this was reachable.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00968.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1Female beetles working alone or in cooperation with a male excavated vertical, tunnel‐shaped brood chambers. Each chamber was filled with dung to form a cylindrical brood mass which contained two eggs, one near each pole.2To examine the possible relationship with other Onitini (which lay either one or several eggs per brood mass) factors that influence the two‐egg programme were studied. Brood masses with only a single egg were formed if excavation was resumed prematurely. Conversely, when excavation was suppressed several oviposition programmes fused to produce a multi‐egg brood mass.3The larvae repaired their chambers in the typical Scarabaeine manner by building a self‐supporting wall formed from their own excrement. This behaviour also prevented direct contact and fighting between adjacent larvae in the same brood mass, and it allowed the larvae to survive inside artificial brood balls. Similar behaviour was observed in larvae ofOnthophagus tauntsandOntho‐phagus vacca(which develop in one‐egg brood masses). The evolution of nesting habits that involve multi‐egg brood masses or free‐standing brood balls may depend on the pre‐existence of this larval

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00969.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The bush cricketsPlatycleis albopunctata(Goeze) andMetriop‐tera roeselii(Hagenbach) interact acoustically in the laboratory. The interaction is principally one‐way, resulting in modification of the song pattern ofP. albopunctataor its inhibition. Similarity of the frequency spectra of songs of both species is one of the principal reasons for reactivity.2Nymphal maleP. albopunctataindividuals are randomly distributed in denseBrachypodium pinnatumL. grasslands. Adult males become regularly spaced with the onset of singing activity. Acoustic behaviour is the most likely mechanism maintaining regular spacing within the maleP.albopunctatapopulation.3In many localities juvenileP. albopunctataandM. roeseliiare sympatric, occurring together in the same vegetation.4With the onset of singing activity by the adult males the two species separate though there is no detectable difference in habitat preference.5The separation is effected by a negative phonotactic response byP. albopunctatato the song ofM. roeselii. It is suggested that this response is derived from behaviour patterns that result in ‘territorial’ spacing within theP. albopunctata(male) population.6This behaviour prevents the occurrence of song modification in the field but also excludesP. albopunctatafrom areas of suitable habitat where the population density ofM. roeselii

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00970.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1Life tables were constructed for solitary and coexisting populations of univoltineFiorinia externaFerris and bivoltineTsugaspidiotus tsugae(Marlatt) (Homoptera: Diaspididae), two exotic scale pests of eastern hemlock,Tsuga canadensisCarriere, in the northeastern United States.2Solitary and coexisting populations ofF. externahad similar survivorship and population growth rates resulting in an annual increase in density of 7–16%. Survivorship of solitary and coexisting populations ofT. tsugaealso was similar, but growth rates differed substantially. While solitary populations increased their density by 68% annually, populations coexisting withF. extemawere reduced 74% each year.3The annual reduction inT. tsugaedensity where it coexists withF. externawas due in part to interspecific competition which resulted in higher mortality to nymphs from dispersal and starvation and in lower fecundity of adult females relative to solitary populations. A host shift by the parasitoid,Aspidiotiphagus citrinus(Crawford) (Hymenoptera: Aphenlinidae) fromF. externatoT. tsugaein autumn also accounted for 71% of the annual decrease inT. tsugaenumbers. Therefore,F. externaadversely affects the growth ofT. tsugaepopulations not only because of its superior competitive ability but also because adult para‐sitoids which emerge from it subsequently attack nymphs ofT. tsugaein autumn.4Parasitism and starvation of nymphs resulting from competition were the key mortality factors in the population dynamics of these exotic hemlock sca

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00971.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The chrysomelid beetle,Cephaloleia consanguinea(Hispinae), is a monophagous herbivore ofHeliconia imbricata(Zingiberales: Heliconiaceae) in wet lowland forests of eastern Costa Rica.2Within the study area parasitism by eulophids and trichogrammatids (Hymenoptera: Chalcidoidea), the most common source ofC. consanguineaegg mortality, varied in intensity from 35% to 50% during 1974–77.3Spatial relationships between the probability of parasitism and egg density per leaf were the net result of two opposing trends. The probability of at least one egg on an egg‐bearingH. imbricataleaf being encountered and parasitized (here termed a ‘discovery’ of that leaf by parasitoids) increased significantly as egg density per leaf increased. The conditional probability of parasitism for other eggs present, given an attack on one egg, decreased with increasing egg density.4The net result was a decrease in the overall probability of parasitism as egg density per leaf increased. Host aggregation appears beneficial in reducing the intensity of parasitoid attacks.5Despite this inverse relationship between the overall probability of parasitism and egg density per leaf, a model based on the binomial distribution provides a good description of the spatial aspects of this host—parasitoid in

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00972.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The feeding cycle for male tsetse flies and the pregnancy cycle for females are used as frameworks for investigating the field behaviour ofGlossina morsitans centralisMachado in Zambia, and hence the sampling biases of different capture devices.2Flies were collected in the field using hand nets and an electric back pack on foot patrols, and hand nets, hand‐catching and an electric screen on landrover patrols. They were analysed for wing‐fray, vein‐length, chloroform‐extractable fat and haematin. In addition, samples of laboratory‐bred females killed daily during their second pregnancy cycle were analysed for the last two parameters.3The daily flying time of males is estimated from the fat—haematin curve to be about 32 min/day, which is identical to previous estimates forG. morsitansfrom Tanzania.4From the varying numbers and fat content of male flies caught by the different sampling methods during the course of the feeding cycle it is concluded that both haematin levels and fat reserves influence fly behaviour.5Comparison of the frequency distribution of wild‐caught and laboratory‐bred females along the corrected residual dry weight axis of the pregnancy cycle suggests that the results of combined electric‐trap and hand‐net sampling reflect the actual frequency distribution in the wild population at least for the first 7 days of the pregnancy cycle; but females in the last 2 days of their pregnancy cycle are apparently unavailable to sampling devices, perhaps because of their reduced flight activity.6The very variable percentage female catch (10.9–43.4%) returned by the different sampling methods is discussed in the light of the detailed analysis of the differential availability of male and female flies t

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00973.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1An analysis of host searching behaviour suggests that female parasitoids respond to aphid odours bringing them to the region of an aphid colony.2Syrphid hosts are located within the aphid colony by response to contact chemicals on the larval integument.3The behavioural mechanisms used by syrphid larvae to resist attacks and the subsequent responses made by parasitoids are described.4Oviposition behaviour and host size preferences of parasitoids are described.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00974.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.1The incidence of wing polymorphism varies seasonally in field populations ofPtinella apteraandPtinella errabundawith alatae increasing in abundance in summer.2In laboratory cultures ofP. apteraalate development varies with temperature. This implies that morph determination is based on a physiological switch sensitive to temperature and possibly other adaptively relevant environmental factors.3AlateP. apteraproduce a higher proportion of alate offspring than do apterous parents suggesting an inherited component in polymorphism control, or some form of maternal effect.4The female biased sex ratio expected of a regularly inbreeding species was found only in the alate morph. Apterous beetles show a 1:1 sex ratio which is explained by the females' limited capacity to store sperm, the enormous size of the sperm, and the consequent need for multiple insemination.5Ptinella errabundais thelytokous but fails to realize the potentially doubled fecundity associated with parthenogenesis. Both the number of eggs produced and their viability is lower than in bisexual congeners.6Enhanced colonizing ability, rather than energy economy, is considered to be the most important selective advantage of parthenogenesis toPtinellain the subcortical habitat.7The spatial and temporal heterogeneity of the subcortical habitat is considered to have favoured the evolution and maintenance of parthenogenesis and wing polymorphism inPtinella.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1981.tb00975.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY