摘要:

A general procedure for formulating mathematical models of pesticide effectiveness is presented, consisting of a differential equation for deposition and degradation of the pesticide in the environment, a differential equation for intake and clearance of the pesticide by the insects, and a functional equation relating the hazard function of the insects to their curve of pesticide retention. Differences among previously developed models for pesticide-induced mortality have not been recognized, and their application to new situations has been limited by these unrecognized differences. Examples of the proposed procedure are developed and applied to two contrasting data sets from the literature. Because the model is formulated using the hazard function, the procedure can be used for modeling and analyzing data from many different kinds of studies and for comparing results from different kinds of studies.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.439

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Data were gathered during two years on the death and removal of gypsy moth.Lymantria disparL.. larvae tethered by threads in various forest microhabitats where gypsy moth densities were low. These data were used to estimate larval mortality rates due to predation, after first correcting for several sources of bias. Values were similar for young and old larvae. but were higher and more variable in the second year. The estimates were used to run Monte Carlo simulations to determine variations in daily predation rates. The average daily predation rate for one of the years, 0.121, was very close to the daily mortality rate found from declines in population estimates between early and late-larval instars obtained from mark-recapture studies. In this low-density gypsy moth population, predation was by far the most important mortality factor.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.448

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The effect of photoperiod, temperature, and humidity on oviposition and egg development was determined to optimize laboratory rearing ofNeodiprion fulvicepsCresson on cut branches of ponderosa pine (Pinus ponderosaDougl. ex Laws). The maximum number of eggs laid and eggs hatched occurred at 15°C. No oviposition occurred at 4°C. Egg development time was too slow to be practical at 10°C; no eggs hatched after 75 d. No differences in number of eggs laid occurred at 30, 40, and 50% RH; however, number of eggs laid was significantly lower at 60%. The maximum number of eggs hatched and the shortest egg development time occurred at 50% RH. Photoperiod had no effect except on the percentage of hatch, which was greatest under short-day conditions. Egg incubation times were slightly shorter on seedlings than on mature cuttings.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.456

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Stenopogon inquinatusLoew forages across a wide range of diurnal temperatures. Changes in perch height and body posture allowed the flies to maximize air temperatures experienced when environmental temperatures were low and to encounter a relatively narrow range of air temperatures in the middle of the day. In addition, early in the day they basked by orienting their longitudinal and dorsoventral body axes perpendicular to the sun. Their behavior varied with environmental temperatures in ways that indicate that perching flies thermoregulate by influencing radiative heat gain and the air temperatures and wind speeds that they experience.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.459

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The effects of the defensive chemistry ofSolidago altissimaon the cabbage looper,Trichoplusia ni(Hübner), were shown using artificial diet bioassays. LyophilizedS. altissimaleaves were incorporated into an artificial diet. Leaf powder also was extracted in hexane, methanol, and water, and the extracts and postextraction residue were incorporated separately into artificial diets. The control contained cellulose powder in place of leaf material. Also, larvae were grown on live, intactS. altissimaplants. The mortality rate was 100% in the whole-leaf powder and methanol extract diets, 97.2% in the hexane extract diet, and 96% in the live-plant experiment. Mortality on the water extract diet (12%) and on the residue-containing diet (13%) was lower than that on the cellulose powder control (17.4%).S. altissimacontains chemicals that severely reduce larval survivorship ofT. ni, but once these chemicals are removed through extraction, the larvae are able to use the nutrients contained in the leaves. These nutrients increase survivorship to adulthood above that on the cellulose control hut do not significantly affect time to pupation, pupal mass, or fecundity.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.465

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The mean adult body size of male and nonblood-fed femaleCulex nigripalpusTheobald mosquitoes showed a highly significant negative correlation with water temperature in the field. Large females were more successful in obtaining blood and developing eggs during an extended period of drought from March through September 1987. Small females emerged from field-collected pupae but were less successful in blood feeding and developing eggs in the field during the period of drought.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.469

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The longevity of adult female western corn rootworms,Diabrotica virgifera virgiferaLeConte, maintained on diets of squash blossoms, sunflower ray florets or inflorescences, and goldenrod inflorescences was significantly reduced compared with beetles maintained on corn ears. However, beetles survived for extended periods on these diets and produced viable eggs. Oviposition rates were inversely proportional to adult longevity so that total oviposition was largely unaffected by diet. By contrast, adult female northern corn rootworms,Diabrotica barberiSmith&Lawrence, showed only minor differences in longevity on the alternative diets. Adult emergence of both species from corn plots previously interplanted with corn, squash, or sunflower in close proximity was similarly distributed among the three parental foods, demonstrating that considerable oviposition occurs where larvae that specialize in corn cannot feed. When emergence was monitored at least 4.5 m away from adjacent host species, significantly more adults emerged from areas previously planted in corn. These results indicate that oviposition near larval food might be directed more by long-range volatiles from corn than by visual or physical attributes of plants within sites. Choice of ovipositional sites and adult foods represents clearly distinct behaviors in female rootworms, and western corn rootworm, in particular, will lay eggs in sites where feeding reduces fitness.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.474

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The concentrations of copper (Cu), iron (Fe), nickel (Ni), and cadmium (Cd) were analyzed in the pupae ofBupalus piniarius(L.) andPanolis flammea(Denis and Schiffermüller) reared on needles collected from the same sites with different heavy-metal levels. Metal analysis on an individual basis revealed specific differences between the two common defoliators of the Scots pine (Pinus sylvestrisL.). The highest heavy-metal concentrations inB. piniarius(Cu 137, Fe 83, Ni 2.1, Cd 0.9 μgg−1)andP. flammea(Cu 89, Fe 59, Ni 5.3, Cd 2.9 μgg−1)were recorded in those reared on needles from the vicinity of the emission source in Finland. The decreasing trend of the log-transformed metal concentrations followed a linear regression model with increasing distance from the factories. The ratio between the concentration of copper and iron in the insects and that in the needles was proportionally lower in heavily polluted areas. Cadmium bioaccumulation was observed inP. flammeabut not inB. piniarius.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.481

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

In the Marigat Location, Baringo District, Kenya, Africa, a survey was conducted from November 1986 to August 1987 to study the microclimate of termite mounds and animal burrows in relation to the relative abundance of sandflies of the generaPhlebotomusandSergentomyia. Soil temperature was the most stable parameter in both sites (CV = 4.9%), ranging from 24.0 to 31.7°C in termite mounds, with a monthly average of 28.6°C, and from 21.7 to 30.0°C in animal burrows, with a monthly average of 25.6°C. Soil moisture content showed a greater degree of variability (CV = 43.7%) with a range of 10.0–47.5% in termite mounds (monthly mean = 29.9%), while in burrows 1.0–48.5% was monitored (monthly mean = 23.8%). Adult sandflies could therefore withstand high temperatures and low moisture content. Correlations between relative abundance of sandflies and soil microclimatic factors were positive for the genusSergentomyia, whereas for the genusPhlebotomusthe coefficients were positive in animal burrows and negative in termite mounds. However, none of the coefficients of correlation was statistically significant.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.486

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Wind tunnel bioassays were performed to examine upwind flight by pink bollworm moths,Pectinophora gossypiella(Saunders), to different parts of the cotton plant (Gossypium hirsutumL.). More moths approached and landed on flowers than on flower buds, bolls, or leaves. Mated female moths were more readily attracted to flowers than were unmated female or male moths. Attraction of moths to flowers was virtually eliminated by washing flowers in pentane, suggesting that the attraction was mediated by olfactory cues. Moths also responded to a hexane extract of flowers and to flowers without petals. We propose that flower volatiles act as a food lure attracting moths to extrafloral nectaries.

ISSN:1754-5692    

DOI:10.1093/ee/19.3.490

出版商:Oxford University Press    

年代:1990

数据来源: OUP