摘要:

To determine oviposition preference of the bean leaf beetle, 500 females were given a choice of three soils (sandy clay loam, loamy sand, and organic) at four soil moistures (oven dry, 1,000 mbar, 100 mbar, and saturation). Soil moisture was maintained during the 48-h oviposition period by rope wicks of different lengths. The beetles laid the most eggs in the organic soil, followed by the sandy clay loam, then the loamy sand. Wet and moist treatments were preferred to the dry treatments, with few eggs being laid in the oven-dried soil. Differences in oviposition are related to soil c1oddiness, color, and water holding capacity

ISSN:0046-225X    

DOI:10.1093/ee/12.2.426

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The functional responses of all feeding stages ofLeptothrips mali(Fitch) to various densities of selectedPanonychus ulmi(Koch) stages were determined in the laboratory at 23.9 ± 1°C. Functional response data were obtained for the followingL. mali-P. ulmicombinations: first-stage larvae ofL. maliwithP. ulmieggs and adults, second-stage larvae or adult femaleL. maliwith adultP. ulmi.To estimate the relationship between the number of prey killed and prey density for the selected predator-prey combinations, various mathematical models were fit to the data. No functional response was found when first-stage larvae were provided adult femaleP. ulmi.A sigmoid curve best explained the relationship in all other situations. Search rate increased between the two lowest prey densities when adult thrips were provided adult mites. No such increase was observed with otherL. mali-P ulmicombinations; search rate remained constant. Therefore, for these other stages, the type III response obtained cannot be explained on the basis that the search rate increases over an initial range of low prey densities. A possible explanation may be interference-stimulation of the predator by the prey above some threshold prey density.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.429

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The community structure of mosquito larvae (Diptera: Culicidae) in discarded tires from an 8-ha tire yard was examined in relation to environmental and water chemical parameters. Shaded tires contained over three times as many larvae as sun-exposed tires. Sun-exposed tires were dominated byAedes atropalpus(Coquillett) (52%),Aedes triseriatus(Say)(24%), andCulex restuansTheobald (18%), whereasA. triseriatusalone accounted for 89% of the total larvae in shaded tires. The oviposition rate ofA. triseriatuswas 30 times higher in shaded areas than in exposed areas. Significant differences were found between exposed and shaded tires for 12 of 14 environmental variables. Densities of three mosquito species were significantly correlated with levels of ammonia, color, and turbidity of water in tires. Oviposition preferences, the spacial distribution of tires, and water quality regulate larval mosquito dynamics in tire yards

ISSN:0046-225X    

DOI:10.1093/ee/12.2.434

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Plumeless thistle,Carduus acanthoidesL., and musk thistle,CarduuS thoermeriWeinmann, potted plants were inoculated with eggs ofRhinocyllus conicusFroelich and subjected to four combinations of moist, dry, fertile, and infertile soil conditions in the greenhouse. Significant differences were found between weights of weevils developing in musk thistle under fertile vs. infertile, and moist vs. dry conditions. Insect survival rates showed similar trends, but differences were not significant. Similar results were obtained for plumeless thistle, although significant differences in weights resulted only from fertile vs. infertile conditions

ISSN:0046-225X    

DOI:10.1093/ee/12.2.439

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Preferences and reproduction ofSchizaphis graminum(Rondani),Macrosiphum avenae(F.),Rhopalosiphum padi(L.), andR. maidis(Fitch) were tested on 13 widely grown species of wheatgrass,Agropyronspp., in the seedling and mature stages of growth under controlled conditions in environmental chambers. Results are an index to the role ofAgropyronspp. as potential alternative hosts for cereal aphids and aphid-transmitted plant virus diseases.S. graminumandR. padiwere well adapted to most of theAgropyronspp. tested, especially in the seedling stage.M. avenaereproduced well on matureAgropyronspp. but was not well adapted to seedlings. MostAgropyronspp. were not reproductive hosts forR. maidis.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.442

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

A bioassay using green index cards demonstrated the stimulatory effect of cabbage extracts on oviposition byPieris rapae. The chemicals involved are water soluble, and the butterflies readily differentiated between different concentrations. High concentrations of the glucosinolate sinigrin also stimulated oviposition but had little effect on the spatial distribution of eggs over treated and control areas of cards. Response to cabbage extracts, however, resulted in precise discrimination between treated and control areas throughout the active life of the butterflies. Cabbage volatiles did not enhance stimulation of oviposition on extract-treated cards. The results suggest that more than one nonvolatile chemical is needed for both stimulation of oviposition and selection of the exact oviposition site

ISSN:0046-225X    

DOI:10.1093/ee/12.2.446

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

The level of antibiosis to a leafhopper,Nephotettix virescens(Distant), and a planthopper,Nilaparvata lugens(Stal), was evaluated on ratoons of selected varieties. Results indicate that antibiosis levels in the ratoon crop corresponded well with that previously reported for the main crop of the varieties tested. However, levels of antibiosis to the two pests decreased with plant age in some varieties instead of increasing as reported for the first crop. The results suggest that ratoons may be important in providing a suitable host for rice pests between main crops

ISSN:0046-225X    

DOI:10.1093/ee/12.2.451

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Manure from cattle treated with an intramuscular injection of an avermectin, MK-933 [at least 80% 22, 23-dihydro-5-O-demethylavermectin A1aand not more than 20% 22,23-dihydro-5-O- demethyl-25-de(l-methylpropyl)-25-(1- methylethyl)avermectin A1a], at a rate of 200 μg/ka prevented emergence of adult horn flies,Haematobia irritans(L.), from all collections through 28 days posttreatment. Some adult horn flies emerged from manure collected at 35 days posttreatment and then aged 2 weeks before infestation. Emergence of several endemic insects was severely reduced in the manure of treated animals; however, this treatment did not influence emergence of all the insects. Manure from treated animals appeared to physically disintegrate at the same rate as that from untreated animals

ISSN:0046-225X    

DOI:10.1093/ee/12.2.455

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Extracts from six Brazilian hardwoods were tested for toxic, repellent, antiprotozoan, and antifeedant properties againstReticulitermes flavipes(Kollar) workers. In 4-week no-choice tests, termite survival and feeding varied with wood species and extracting solvent. They generally were lowest onCopaifera multijugaHayne,Mezilaurus itauba(Meissn.) Taubert ex Mez, andPlatymiscium uleiHarms; and highest onCouropita subsessilisPilg. and most extracts ofMicrandra siphonioidesBenth. For termites surviving the no-choice test, the greatest reductions in protozoan numbers occurred on all extracts ofCarapa guianensisAubl. and on hexane extracts ofM. itaubaandP. ulei.In choice tests for feeding preference, termites generally consumed more untreated than treated paper pads, but treated-pad weight loss was not significantly different from the controls for some extracts ofC. subsessilisandM. siphonioides.One to three extracts from each of the six woods were repellent to the termites.

ISSN:0046-225X    

DOI:10.1093/ee/12.2.458

出版商:Oxford University Press    

年代:1983

数据来源: OUP

摘要:

Previous studies that attempted to determine the role of food resources in the population structure of butterflies concentrated on larval host plants. In a habitat with widespread larval resources and a single concentration of adult resources, adultEuphydryas chalcedonawere found more often near the nectar. The number of offspring was inversely proportional to the distance from nectar resources, indicating that these are a primary determinant of habitat selection for this species

ISSN:0046-225X    

DOI:10.1093/ee/12.2.463

出版商:Oxford University Press    

年代:1983

数据来源: OUP