摘要:

Single applications of aqueous sprays of rubidium chloride (RbCl) were made at rates of 0.625–10 kg/ha to cotton, grain sorghum, and hyacinth bean,Dolichos lab-labL., to label the plants and insects on them with elevated levels of Rb. However, at all rates tested there was overlapping of the concentration of Rb in insects collected from treated plants with the Rb content of those from untreated plants. Some entomophagous insect species were labeled with Rb, indicating the Rb moved through the food chain from producers through primary to secondary consumers.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.379

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Laboratory and field testing of a large number of synthetic compounds and many combinations of them revealed that male moths of the redbacked cutworm,Euxoa ochrogaster(Guenée), were attracted to combinations ofZ-5-dodecenyl acetate andZ-8-dodecenyl acetate, with the greatest catches to ratios of 1:2 to 1:5. The attraction of males was improved by the addition ofZ-4-decenyl,Z-5-undecenyl, orE-5-decenyl acetates as 3rd components. These combinations were all specific for redbacked cutworm males and they all attracted males with the full range of wing color patterns. The attraction of males was inhibited byZ-5-decenyl orZ-7-dodecenyl acetates.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.384

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Chaetophlepsis plathypenaeSabrosky, a solitary endoparasite of the green cloverworm,Plathypena scabra(F.), oviposited in 2nd- and 3rd-instar larvae and emerged from 4th-instar larvae. Development time ranged from 25–30 days at 22°–24°C. The parasite was reared almost exclusively from host larvae collected in soybean ecosystems and was more prevalent in lowland (river bottom) than upland habitats; seasonal parasitization ranging from 5–12.5% compared to<3%, respectively.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.387

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

In North America, area-wide outbreaks by the gypsy moth,Lymantria dispar(L.), have persisted for as much as a decade. The analysis of records accumulated on this insect throughout the northeastern United States indicates that such outbreaks are most likely to persist from one year to the next when insect densities range widely among the subpopulations in the overall population system. Area-wide outbreaks are likely to decline during years when numerical variability is minimal among the subpopulations. To be accurate, future projections of the natural maintenance and decline of area-wide outbreaks must account for the intrapopulation phenomena that give rise to these results.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.389

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Eighteen quantitative light trap samples collected between July 29 and Aug. 12, 1976, at the McCloud River Preserve, Shasta County, Calif., contained 19 species of caddisflies.Hydropsyche oslariBanks comprised over 96% of the 4200 adults collected in midsummer samples. Males predominate in theH. oslaripopulation, although the proportion of males decreases as number of individuals decreases. Maximum and minimum air temperatures influence not only the number of species and individuals collected, but also the proportion of maleH. oslari.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.396

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Field trapping tests with a range of pheromone component ratios throughout the year showed that there were noticeable shifts in the best treatment for trapping male omnivorous leafroller moths,Platynota stultana(Walsingham). The best (E)-11/(Z)-11-tetradecenyl acetate ratios were those with 88–94% of the E-11 compound during the cooler months, whereas those with 70–80% of the E-11 compound captured the most males during the warmer months. Female moths produce a ratio of ca. 88:12 E:Z throughout the whole season. It is postulated that the high release rates of mixtures in the warm months effects male orientation disruption to the natural blend, but that other ratios, such as 80:20 or 70:30 become effective attractants when the release rate increases as the result of warmer temperatures.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.399

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Four species of predators were each exposed to different densities of tobacco budworm,Heliothis virescens(F.), eggs in the presence or absence of the cotton aphid,Aphis gossypiiGlover. When alternate prey (aphids) were absent, the functional response of most predators was usually directly proportional to the density, ofHeliothiseggs. Under these conditions larvae ofHippodamia convergensGuérin-Méneville were the most effective predators, followed by adult lady beetles,Chrysopa carneaStephens larvae, adultGeocoris punctipes(Say), andOrius insidiosus(Say), respectively. Among all predators exceptG. punctipes, total percentage consumption ofHeliothiseggs was reduced when aphids were available as alternate prey.GeocorisandHippodamiaadults were least affected by the presence of aphids whileChrysopaandHippodamialarvae were most affected. Interactions among the species were generally of a density-dependent nature.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.402

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Phloem of loblolly and shortleaf pine trees attacked by the southern pine beetle,Dendroctonus frontalisZimmerman, exhibited a characteristic drying followed by rehydration. Trees With initially higher phloem moistures retained relatively higher levels during drying following attack. Limited population estimates suggested that brood survival was lower in trees with high moisture. In the laboratory, rearing bolts which were waxed to maintain higher phloem moisture had lower beetle survival than unwaxed bolts. High phloem moisture was associated with the formation of long larval mines, instead of feeding chambers, which in turn led to lowered survival. Emergence of the survivors was positively correlated with phloem moisture, suggesting that high moisture was beneficial to larvae and pupae in the outer bark.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.405

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

Two different models have been proposed for predicting elemental accumulation by arthropods. Parameters of both models can be quantified from radioisotope elimination experiments. Our analysis of the 2 models shows that both predict identical elemental accumulation for a whole organism, though differing in the accumulation in body and gut. We quantified both models with experimental data from134Cs and83Sr elimination by crickets. Computer simulations of radioisotope accumulation were then compared with actual accumulation experiments. Neither model showed exact fit to the experimental data, though both showed the general pattern of elemental accumulation.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.411

出版商:Oxford University Press    

年代:1978

数据来源: OUP

摘要:

The occurrence of various presumably sympatric species of Nearctic yellowjackets was determined in widely separated areas. Long-term trapping withn-heptyl butyrate in California, Maryland, and Minnesota disclosed the presence of up to 6 sympatric species ofVespulain some localities. The most responsive includedVespula pensylvanica(Saussure),Vespula sulphurea(Saussure), andVespula atropilosa(Sladen). Male yellowjackets,Vespula germanica(F.),Vespula maculifrons(Buysson), andDolichovespulaspecies were nearly unresponsive to synthetic attractants but trapping combined with net collection indicated additional sympatry in some localities. Traps revealed the presence of various species ofVespulain specific localities and traps were used to determine the relative seasonal abundance only of responsive species. The detection sensitivity of trapping may be enhanced by the simultaneous use of protein, carbohydrate or various synthetic attractants.

ISSN:1754-5692    

DOI:10.1093/ee/7.3.418

出版商:Oxford University Press    

年代:1978

数据来源: OUP