摘要:

Despite many examples of plants' hypersensitive reaction against pathogens, there are exceedingly few examples of hypersensitive reactions having any importance against insect herbivores. However, such plant defense mechanisms may be widespread among more sedentary insect herbivores. The examples in which a hypersensitive reaction was elicited against insect herbivores were against galling insects, bark beetles, adelgids, and siricids. The intimate and sessile interactions during insects' egg and larval stages may have selected more specific and more complex defenses, because of the greater and more varied opportunities that the host plant has for regulating the lives of its intimate associates. Thus, it is argued that the intimate association of these herbivores during egg and larval stages set the scenario for the evolution of this plant defense mechanism. The dearth of accepted examples of hypersensitive reaction against insect herbivores may not reflect its actual frequency and occurrence in nature. Further investigation on plants' hypersensitive reaction against insect herbivores may shed light on the ecology and evolution of insect-host plant association.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1173

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Intraspecific intrinsic variation in foraging behavior is a common but often overlooked feature of parasitoids. These variations result from adaptations to the variety of foraging circumstances encountered by individuals of the species. We discuss the importance of understanding the mechanisms governing these intrinsic variations and the development of technologies to manage them. Three major sources of variation in foraging behavior are identified. One source for variation is genotypically fixed differences among individuals that are adapted for different foraging environments. Another source of foraging variation is the phenotypic plasticity that allows individuals to make ongoing modifications of behavior through learning, which suits them for different host–habitat situations. A third factor in determining variation in foraging behavior is the parasitoid's physiological state relative to other needs, such as food and mating. A conceptual model is presented for comprehensively examining the respective roles of these variables and their interactive net effect on foraging behavior. We also discuss proposed avenues for managing these variations in applied biological control programs.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1183

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The Rocky Mountain grasshopper,Melanoplus spretus(Walsh), was the most serious agricultural pest in the western United States and Canada before 1900. Immense swarms periodically migrated from the northern Rocky Mountain region and destroyed vast quantities of crops throughout the western and central portions of the United States and Canada during the mid-1800s. However, in the late 1800s, this species began a precipitous decline, and the last living specimen was collected just after 1900. There has been no satisfactory explanation for the sudden disappearance ofM. spretus. Macroscale changes in the western United States (i.e., climatic events, loss of Indians and bison, and the introduction of cattle) do not appear to have been of sufficient ecological intensity to explain the extinction. However, because the distribution of the insect was extremely compressed due to a natural population crash in the early 1880s, small-scale changes may account for the disappearance ofM. spretus. Within the region that this species occupied in the late 1800s, oviposition and early nymphal development occurred almost exclusively in riparian habitats. Intensive anthropogenic effects (i.e., tillage; irrigation; loss of the beaver; and introduction of cattle, plants, and birds) were associated with virtually the entire range ofM. spretusin the late 1800s. We suggest that localized agricultural destruction of the insect's habitat and the introduction of exotic species caused the extinction ofM. spretus.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1194

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

A sublethal concentration (2.5%) of tricalcium phosphate, a known insect population suppressant, was used to investigate the effect of this salt on the energy budget of the khapra beetle,Trogoderma granariumEverts. Larvae fed tricalcium phosphate had a longer developmental period and one extra instar; they ingested more food and had a lower mean assimilation efficiency.T. granariumis relatively resistant to tricalcium phosphate and concentrations only in excess of 2.5% will cause any appreciable population suppression. The higher mortality and longer development time of populations treated with tricalcium phosphate were compensated for by a higher production of eggs. Greater numbers of progeny and living longer may even increase consumption. Energy budgets of other stored-product insects were compared with that ofT. granarium.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1206

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

In the fall, adult face flies enter a facultative diapause in which mating and ovarian maturation do not take place, and their fat bodies become hypertrophied. Laboratory studies implicate short photoperiod as the primary inducer of diapause, but the response is temperature-dependent. Among field populations in Ames, Iowa, however, most teneral adults begin to enter diapause in the second week of September every year with no detectable effect of temperature. A range of light intensities<1,730 lux (160 ft-c) was applied to populations of flies at different photoperiods and temperatures. Precise calibration of light intensity was achieved with crossed polarizing filters placed over populations of eclosing flies. In a split-plot experiment, reduced light intensities led to significantly more diapause in each of four photoperiods. There was no interaction between photoperiod and light intensity. Effects of photoperiod and light intensity on diapause were obtained in split but not constant temperatures.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1217

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Insecticide susceptibility and resistance in populations of pear psylla,Psylla pyricolaFoerster, and the mirid predator,Deraeocoris brevisKnight, were evaluated through biochemical and computer simulation analyses. Pear psylla were resistant to azinphosmethyl and fenvalerate, whereasD. breviswere susceptible. Although esterase detoxification activity was higher in pear psylla than inD. brevis, glutathione S-transferase and cytochrome P-450 monooxygenase activities were similar in predator and prey. Sensitivity analyses predicted that high fecundity and low immigration of susceptible individuals into populations selected by insecticides contributed greatly to the development of rapid resistance in pear psylla. Conversely, lower fecundity and high immigration of susceptible individuals contributed greatly to the lack of resistance inD. brevis. Thus, it appears that life history and ecological factors explain resistance in pear psylla and the lack thereof inD. brevisbetter than do detoxification attributes.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1223

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The response of western flower thrips,Frankliniella occidentalis(Pergande), to color was determined by varying the hue, intensity, and saturation of 84 sticky traps in cucumber greenhouses. Male and female thrips alighted preferentially on traps of bright blue, violet, yellow, and white, whereas green, orange, and UV-reflecting white hues were not attractive. Reducing the reflectance intensity of the attractive hues resulted in a linear reduction in the number of thrips trapped, but reducing the reflectance intensity of the nonattractive colors had no effect. Sufficiently desaturating the attractive hues with white or UV-reflecting white paint resulted in a decreased response, which was attributed to interactions between key wavelengths reflected at 350 nm (UV), 440 nm (blue), and 550 nm (yellow). The addition of yellow wavelengths alone or in combination with UV to a blue hue had negative effects, and the addition of blue wavelengths alone or in combination with UV to a yellow hue also had negative effects. From these data. regression models were developed to predict the response ofF. occidentalisto traps with dominant wavelengths between 400–650 nm, with or without UV reflectance.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1229

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Colorimetric studies of face fly,Musca autumnalisDe Geer, vision demonstrated a close agreement between the spectral responses measured by electroretinogramic or behavioral (phototaxic) techniques. A trichromatic visual system describes colors as they appear to the flies and makes it possible to calculate which colors will contrast with each other. A mixture of ultraviolet and green radiations was calculated to be highly visible against green foliage or blue sky and was demonstrated to be attractive under field conditions.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1242

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Capture of male codling moth,Cydia pomonella(L.), with pheromone-baited sticky traps in an orchard in Kern County, Calif., during 1983–1988 was associated with air temperature, relative humidity, wind speed, wind direction, vapor pressure, dew point temperature, and rainfall. Based on a stepwise logistic regression analysis, mean evening air temperature, wind speed, and vapor pressure significantly affected the probability of moth capture. All moths were captured on dates whose mean evening air temperature was>12.01°C, wind speed was<3.62 m/s, and rainfall was15.8°C (21.1°C maximum daily) were associated with consistent observations of male flight as measured by pheromone traps. Knowledge of weather factors affecting moth capture in pheromone traps could help in interpreting trap catch data and may lead to fewer treatment decision errors.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1253

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Daily and seasonal changes in concentrations of whole-body lipids were examined in adult green cloverworms,Plathypena scabra(F.), to determine if seasonal trends were present. Laboratory-reared moths had a greater percentage of whole-body lipids overall compared with field-reared 5-d-old adults. Laboratory-reared males contained a significantly higher percentage of whole-body lipids than laboratory-reared females. Field-reared male adults contained a greater percentage of whole-body lipids during March, September, October, and November than those adult males reared in July and August. This may indicate a preparation for diapause or migration. Field-reared females showed no temporal differences in whole-body lipids. Inability to detect differences in females may be related to reproductive status.

ISSN:1754-5692    

DOI:10.1093/ee/19.5.1259

出版商:Oxford University Press    

年代:1990

数据来源: OUP