摘要:

Abstract.1. Population characteristics of the brown planthopper, Nilaparvata lugens (Stål), were investigated over eight growing seasons on rainfed rice in the Philippines.2. Three nymphal generation peaks were observed in most seasons. The third peak was not always the largest and peaks varied considerably in size from season to season.3. Generation peaks were less distinct at a second sampling site within an irrigation system, possibly associated with increased asynchrony of planting and the consequent increased immigration potential.4. Mortality was highest for eggs and first instar nymphs. Egg to adult survivorship was estimated as 1–1

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00746.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SLUG AND NETTLE CATERPILLARS. THE BIOLOGY, TAXONOMY AND CONTROL OF THE LIMACODIDAE OF ECONOMIC IMPORTANCE ON PALMS IN SOUTH‐EAST ASIA. Edited by M. J. W. Cock, H. C. J. Godfray and J. D. HollowayZOOGEOGRAPHY OF CARIBBEAN INSECTS. Edited by James K. LiebherrTHE NATURAL HISTORY AND BEHAVIOR OF NORTH AMERICAN BEEWOLVES. By Howard E. Evans and Kevin M. O'Nei

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00747.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. Oniticellus egregius Klug constructs brood ovoids of dung in the soil immediately under the edge of animal droppings. Each successive brood ovoid is enveloped within a soil shell. After completion of brood construction, loose earth is cleared from around the broods to produce a brood chamber. The immatures are then abandoned as eggs or first instar larvae.2. O.planatus Castelnau and O.formosus Chevrolat usually construct brood balls of dung within animal droppings. Each brood is progressively enlarged by the addition of further dung after egg‐laying. This enlargement is slight in O.planatus and marked in O.formosus. Parental females of both species remain in the brood chambers during development of the immatures which are abandoned principally as pupae.3. Under very moist experimental conditions, O.planatus buries dung and constructs broods shallowly in the soil. Such nests are frequently connected to the pad by a short tunnel.4. From a consideration of behavioural patterns it is suggested that the specialized nesting habits of these species have been derived from those of dung‐burying ancestors similar to the modern genus, Euoniticellus, through reduction and loss of tunnelling in the s

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00748.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

MECHANISMS OF WOODY PLANT DEFENSES AGAINST INSECTS: SEARCH FOR PATTERN. Edited by W. J. Mattson, J. Levieux and C. Bernard‐DaganAFRICANISED HONEY BEES AND BEE MITES. Edited by Glen R. Needham, Robert E. Page, Jr, Mercedes Delfinado‐Baker and Clive E. BowmanAPHIDS THEIR BIOLOGY, NATURAL ENEMIES AND CONTROL. Edited by A. K. Minks and P. Harre

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00749.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. Population budgets for Rhynchaenus fagi, based for the most part on samples of beech leaves taken in June, were constructed for a 10‐year period (Northern Ireland) and a 3‐year period (Scottish borders).2. There were years of sustained population growth and sustained decline, but not enough evidence to suggest a cycle. Similar population levels were found at both sites in all but one year.3. Key factors were associated with the adult stage, although egg mortality may also make a significant contribution to population change.4. Unknown sources of mortality embodied in the residual mortality were also suspected of acting in a density dependent manner, compensating for variation in parasitism.5. Death rate of larvae within mines was related to May temperature in Northern Ireland, but not so clearly in Scotl

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00750.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. Reproductive costs associated with flight capability were evaluated in the wing dimorphic planthopper, Prokelisia dolus Wilson, by comparing the life history of traits of winged (macropterous) and flightless (brachypterous) females under controlled laboratory conditions.2. Macropters with large thoraces and fully developed wings maintain a greater investment in flight apparatus than brachypters with small thoraces and reduced wings.3. Associated with greater flight capability in the macropter of P.dolus are shorter adult life, decreased total fecundity, and delayed age at first reproduction compared to brachypterous females.4. Under field conditions where mortality is high, the difference in realized fecundity between the two wing forms living on similar resources is further exaggerated with the brachypter having the greater advantage.5. When the life history traits of the wing forms of P. dolus are compared with traits for nine other species of planthoppers, two similarities emerge. First, the preoviposition period of the macropterous wing form is always longer than that for the brachypter resulting in a reproductive delay. Second, most studies show that macropters are less fecund than brachypters.6. There is no general tendency among planthopper species for macropterous adults to live fewer days or develop more slowly as nymphs compared to their flightless counterparts.7. The reproductive delay and reduced fecundity of the volent wing form of planthoppers supports the notion that flight capability is costly and that phenotypic trade‐offs between flight and reproduction exis

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00751.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. This study examines the shape of the population response curve of the two‐spotted spider mite, Tetranychus urticae Koch, feeding on bean plants, Phaseolus vulgaris L., which have been subjected to one of a range of drought stresses.2. Abundance of spider mites declined at slight drought stress, increased at intermediate intensities of stress, and declined again at severe stress.3. Fecundity showed the same pattern found for total abundance. Developmental rates of immatures, on the other hand, generally increased with stress intensity. Survivorship of immatures and adult females appeared unrelated to stress intensity.4. These results indicate that responses of mites to drought‐stressed beans are nonlinear. Such a pattern helps explain contradictory results obtained for spider mites and other arthropod herbivo

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00752.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

TAXONOMY AND ECOLOGY OF THE JUMPING PLANT‐LICE OF PANAMA (HOMOPTERA, PSYLLOIDEA). By R. G. Brown and I. D. HodkinsonTHE NATURAL HISTORY OF LARVAL MOSQUITO HABITATS. By Marshall Lai

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00753.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. Encarsia pergandiella Howard females develop as primary parasitoids on immature whiteflies, and males develop as secondary parasitoids on females of their own or a related species. The hypothesis that the sex ratio reflects the relative abundance of the two host types was tested in the laboratory using petri dish arenas with varying proportions of early fourth instar greenhouse whitefly (Trialeurodes vaporariorum (West.)) (primary hosts) and pupal female E.pergandiella (secondary hosts). Egg distribution was analysed with respect to sex ratio, super‐parasitism and host discrimination.2. The proportion of primary and secondary hosts parasitized in each treatment reflected the relative availability of each host type. Thus females presented with 75% primary hosts laid more female eggs than male. However, in all treatments, a greater proportion of secondary hosts were parasitized than would be expected from the proportion of secondary hosts available. This indicates that more male eggs were laid than expected.3. More secondary hosts than primary hosts were superparasitized.4. Host discrimination analysis using a new test statistic showed that females generally laid eggs at random with regard to previous parasitism of primary or secondary hosts. However, females in one treatment with 50% of each host type appeared to preferentially oviposit in secondary hosts which did not contain any egg

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00754.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.1. The response curves for the photoperiodic induction of the sexual forms (oviparae and males) differ significantly in an English clone of the pea aphid Acyrthosiphon pisum Harris. Male production is sharply peaked. The late summer scotophases (dark periods) that initiate male production are 1.0–1.5 h shorter than those that initiate ovipara production; the induction of males, but not oviparae, virtually ceases at scotophases longer than 12 h. This disparity suggests that there are two photoperiodic clocks.2. All ovipara‐producing aphids switch spontaneously to virginopara production part‐way through the progeny sequence, irrespective of photoperiod. This may confer the ability to overwinter partheno‐genetically under favourable climatic conditions. Since males are always born last in the progeny sequence this possibility would be pre‐empted unless the terminal male sequences were suppressed by long winter scotophases.3. The role of the photoperiodic response in determining the seasonal phenology was tested in the field by exposing a succession of laboratory‐reared aphids to natural photoperiods, in late summer and autumn. Adult males and oviparae developed synchronously in early October, the difference in critical scotophase compensating for the late appearance of males in the progeny sequence. A large part of the ‘civil twilight’ is photoperiodically active.4. Clones propagated outdoors by isolating aphids in each generation from the terminal sequence of virginoparae did not survive the whole winter of 1985/86. The chances of survival were reduced by severe weather and by the inability of the photoperiodic system to ‘turn off’ the production of early born oviparae which are,

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1989.tb00755.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY