摘要:

Abstract.1The generalization that ferns are under‐utilized by phytophagous insects in comparison to angiosperms may be invalid because of biases involving plant growth form, plant range, and unequal sampling efforts.2Comparison of nineteen fern species with 652 herb species, the angjosperm growth form most similar to the ferns, indicates no significant difference in the mean number of supported macrolepidopteran species. When the herbs are subdivided into annuals, biennials and perennials, only the annual herbs are significantly different than the ferns.3Comparisons of the occurrence distributions for ferns and the herb categories also demonstrate that only the annual herbs support more macrolepidopteran species than the ferns. The same results are obtained when random assemblages of herbs are created that are the same size as the fern assemblage.4Both the occurrence distributions and the species–area relationship for the ferns indicate that host records for insects feeding on ferns may be grossly incomplete.5The similarity of exploitation of ferns and perennial herbs by the Macro‐lepidoptera suggests that other foliage feeding insects may also use ferns at levels equivalent to angios

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01129.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1The changes in sex ratio of a population ofColias lesbiawere studied for four consecutive years.2A constant sex ratio was found in the samples taken in the 34 days following the last harvest of the alfalfa.3For the samples taken 35 or more days after the harvest the sex ratio decreases as the total number of adults caught increases.4The indirect evidence collected suggests that differences in emigration tendencies between sexes play a major role in determining the sex ratio in this species.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01130.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1Predation on a species of leaf‐mining insect,Eriocraniellasp., by two species of ants,Crematogaster ashmeadiiMayr andPseudomyrmex brunneaF. Smith, is documented.2Exclusion experiments show that ants and other terrestrial invertebrates can greatly contribute to mortality of leaf‐miners and significantly decrease survivorship of the larval stages even when densities are low.3Comparison of two leaf‐mining species,Eriocraniellasp. andCamerariasp. nov. Davis, indicates that factors of mortality depend on the maturity of the leaf being

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01131.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.Icerya seychellarum, a polyphagous phloem feeding coccid, was discovered on Aldabra atoll in 1968. It was not recorded by early expeditions to the atoll, and is probably a recent introduction. Its infestation rose to a peak density around 1975, and thereafter declined, as revealed by a comparison of fifty‐one woody taxa common to three surveys. In 1975, twenty‐one taxa were ‘heavily’ infested and twenty‐one ‘lightly’/‘moderately’ infested. By the end of 1978, no taxa remained ‘heavily’ infested and thirty‐seven were ‘lightly’/‘moderately’ infested. The state of vegetation showed negligible change between the 1976/77 and 1978 surveys, refuting an earlier prediction that it would be substantially modified by theIceryainfestation.The subsequent decline in infestation cannot here be attributed to the development of natural enemies. Possible reasons, which are discussed, include changes in the qu

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01132.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1The parasite complex associated with nymphal and adult typhlocybine leafhoppers consists of the following: Dryinidae (Aphelopusspecies), Pipunculidae (Chalarusspecies) and Diapriidae (Ismarus dorsigerCurtis), the last being parasitic on species ofAphelopus.2The life cycles and temporal distribution patterns of twenty‐nine species of Typhlocybinae are summarized together with the life cycles of BritishAphelopusandChalarus.3Closely related primary parasite species differ in their adult emergence times. Species differences in adult emergence times of diapausingChalarusare correlated with species differences in host relations.4Each primary parasite genus contains both monophagous and polyphagous species. Each polyphagous species shows a distinct ‘preference’ for a particular range of hosts.5The parasite complexes of different leafhopper communities are compared, and it is concluded that it is the taxonomic composition of the leafhopper communities which is chiefly responsible for the structure and taxonomic composition of their associated parasite complexes.6Individual species of bothAphelopusandChalarusshow a degree of sensitivity to the physiology of their hosts, so achieving a high degree of sync

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01133.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1Life history data were gathered for south FloridaOncopeltus fasciatusreared from eggs onNerium oleanderseeds and milkweed seeds in the laboratory.2Milkweed seeds were found to be a superior food source sinceO.fasciatusgrew faster, laid more clutches, and has a higher total fecundity on milkweed seeds.3FruitingN.oleanderwas found to be a better food source than nonfruiting milkweeds in a summer field study in south Florida since no nymphs survived to the adult stage on nonfruiting milkweeds but some did onN.oleander.4O.fasciatusadults and nymphs are abundant onN.oleanderin the summer in south Florida whenN.oleanderis fruiting; noO.fasciatusnymphs are found in the summer on the milkweeds which are not fruiting.5O.fasciatusleaveN.oleanderin the autumn when milkweeds start to fruit and can then be found on fruiting milkweeds.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01134.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1Third instar larvae ofA.rufipeswere found in short vertical shafts in the soil beneath horse dung and they entered the underground brood masses ofG.spinigerwhen these occurred beneath the same deposit of dung.2A.rufipeslarvae excavated shafts (60–80mm deep) beneath dung in cages. Just before diapause they burrowed down to the floor of the cage. Burrowing was inhibited in compact soil and in very dry soil. The feeding larvae were attracted to dung and to moisture and they readily attacked other larvae with their mandibles.3In cages which containedG. spinigernests theA.rufipeslarvae burrowed down to feed on theG.spinigerbrood masses.G.spinigereggs and larvae did not act as attractants but they were often destroyed if theA.rufipeslarvae encountered them by chance.4In cages which containedG.stercorarxusnestsA.fossorlarvae burrowed down to feed on the brood masses if no dung was provided at the surface.5This non‐obligatory parasitism arises from the normal behaviour of the larvae and is usually of trivial significance, but under certain conditions the protected environment of an underground nest may favour the survival of the invading lar

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01135.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1The cactophagous insect community on opuntias is analysed to show the number of insect species in different taxa. An extension of this analysis gives the average species complement on large and small opuntias.2A highly significant positive correlation is found between the total number of phytophagous insect species on individualOpuntiaspecies and a measure of the overall ‘architecture’ of their host plants.3The specificity of the phytophagous insects on opuntias is briefly considered and the community as a whole analysed by guilds. The co‐evolution of theOpuntia‐feedinginsects and their hosts has culminated in a community of specialist insects to the exclusion of nearly all generalist phytophages.4The life history strategies of theOpuntia‐feedinginsects are reviewed. Common to all developmental stages are morphological and behavioural adaptations that reduce the risk of attack by natural enemies. This is clearly the consequence of living on structurally simple host plants where there is little place to hide.5The possible influence of insect herbivores onOpuntiaevolution is discussed.6An understanding of the interactions between the phytophagous insect community and opuntias has clear implications for the biological control of alienOpu

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01136.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1A population ofTipula sacrawas studied intensively from 1969 to 1974 in a series of abandoned beaver ponds. Beavers recolonized the ponds from 1974 to 1976 and again in 1978.2The basic life‐cycle is of 2 years duration, but cohort‐splitting occurs in the autumn as a result of some larvae growing faster and completing the life‐cycle in 1 year.3Some periods are more favourable for growth than others and the size of the fast‐growing cohort varies from year to year. This insight allows some anomalies in the estimates of population size to be explained and life budgets have been produced for three year‐classes.4The short‐fall in realization of egg potential is massive, apparently due to heavy female mortality by predation and the prevention of oviposition by inclement weather.5Mortality rate is relatively low and constant from stage II larvae until pupation, but increases to adult emergence. There is a correlation between larval density and mortality rate.6Certain aspects of the life‐history (e.g. high fecundity, variability in growth rate) appear to fit the species to life in a temporally uns

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01137.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract.1The colour morphs of fourth and fifth instar nymphs ofE. cyclopsandE. urticaeare described and their geographic distributions in southeast Wales are examined.2Morph frequencies are influenced byChalarusparasites (Diptera: Pipunculidae).

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1980.tb01138.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY