摘要:

An analysis of a pheromone trapping system was performed to study the possibility of theoretically estimating the efficiency of a boll weevil pheromone field trapping system. Release-capture data for a single trap were used to establish percent capture versus distance from the trap. A computer simulation model predicting trapping efficiency showed that results are very sensitive to the responsiveness characteristics of the population. Theoretical results also showed sensitivity to trap spacing and identified some specific research needs.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.799

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Tests used to monitor the quality of laboratory-reared insects must be reproducible, economical and simple if they are to be widely applied. A standard of quality must be established with which the laboratory-reared population may be compared. The wild insect of the species being monitored is deemed to be the best standard even though its application may often be difficult.Comparisons of the wild-standard and laboratory-reared insect populations (monitoring) should include those components of the biology and behavior of the species which are most important to its survival. These components are identified as life history, dispersal, survival, locating of mating sites, courtship and mating, oviposition and larval survival. Each component in this sequence is composed of identifiable traits which are subject to monitoring. The possible sources and types of variation in these traits, the means by which the variations have been measured, and the ways in which the experimental processes have been reduced to simple monitoring systems are discussed in this review.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.807

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

All species possess basic characteristics which distinguish them from other species. However, genetic research has demonstrated the uniqueness of individuals in sexually reproducing organisms. Also, population studies have indicated that species consist of local units that can vary in both space and time. The differences observed among and within populations may extend to any part of the genotype and are believed to result from genetic adjustments that lead to the production of a phenotype adapted to the local environment. The idea that environmental selection patterns are responsible for the regulation of genetic variation in populations suggests the need to conduct ecological genetic studies on native populations being sampled to establish laboratory colonies for biological and/or genetic control programs. In the absence of field information, sampling procedures tend to be haphazard in terms of securing adequate amounts and kinds of genetic variation for initial colonization purposes.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.815

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Electrophoretic variants at five loci have been studied in laboratory and factory (mass-production) adult screwworm flies. The pattern of genetic changes observed in several factory strains is very similar, but these changes differ from those which occur in smaller laboratory populations. Genetic variation in all colonies, however, decreases with colonization time. The most dramatic change occurred at the α-glycerophosphate dehydrogenase locus. This enzyme serves a key role in energy flow during flight and its activity is sensitive to temperature changes. An allele which is rare in natural Texas populations consistently becomes fixed, or nearly so, in each strain reared under factory conditions. These genetic changes are due to conditions peculiar to the factory, i.e., rearing at constant high temperatures, selection for rapid development time and reduced flight activity. The use of electrophoresis to measure genetic changes in ecologically important proteins as a quality control monitoring program is proposed.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.821

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Crop cuitivars resistant to insect vectors of plant viruses are likely to alter the population size, activity, and probing and feeding behavior of the vector, thereby influencing the pattern of virus spread. The effect of a vector resistant cuitivar on virus spread will depend upon the type of resistance (nonpreference, antibiosis, or tolerance), the level of resistance, the relative importance of primary and secondary virus spread, the length of the acquisition, inoculation, retention, and latent periods of the virus, and the effect of virus infection on vector resistance in the plant. Each combination of these factors may result in a different effect on virus spread; the possibilities are discussed. Because of the complexities involved, a thorough understanding of the ecology of virus spread, the biology of vector resistance, and the ecology of the vector arc essential to predict the effect of vector resistance on virus spread.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.827

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Genetic improvement of insects has generated only a moderate amount of discussion in recent years because entomologists believe that little of practical importance has been achieved. Meanwhile, the problem of maintaining the genetic quality of laboratoryreared insects has become prominent.However, some insects have been improved genetically. Domesticated and semidomesticated insects such as the honey bee and the silkworm have been improved in many ways through selection and hybridization. Some parasites have also undergone selection to improve insectary production or field effectiveness, or both. “Improved” insects for laboratory tests may be obtained by hybridizing 2 inbred lines, which often yields a vigorous, uniformly variable insect.Parasites, or any insect that must survive and reproduce in a natural environment, present particularly difficult problems for a genetic improvement program. Desirable attributes to be selected must be clearly definable, which is often quite difficult given our current lack of knowledge of the behavior of parasites under natural conditions. Adequate genetic variability must be provided for so that selection can operate, and adequate selection procedures are important. Finally, maintaining the integrity of the improved insects may or may not be important, depending upon how the parasites are used.Heterosis has been largely ignored in programs for the genetic improvement of parasites, but some data suggest that heterosis could increase the effectiveness of inoculative and inundative releases of parasites or predators. There is still not enough experimental evidence to support judgments about the cost/benefit ratios of genetic improvement, however. Future studies must include field evaluation to demonstrate the value of such improvement programs.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.833

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Hemolymph volumes were observed to decrease significantly inPeriplaneta americana(L.) andBlatta orientalisL. when treated with either rose bengal or erythrosin B and subsequently exposed to fluorescent light. Dye-fed or dye-injected roaches contained less hemolymph after light exposure than did untreated, light-exposed roaches or dye-treated and untreated roaches in darkness. Dye-treated, light-exposed roaches also contained larger volumes of crop fluids than roaches in any of the other treatments. Hemolymph volume progressively decreased and crop volume increased in dye-fed roaches exposed to light for up to 63 min. The results of these studies indicate that a transfer of hemocoel fluids from the body cavity into the alimentary canal and perhaps into tissue occurs in dye-treated insects when they are exposed to light.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.840

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

The survival and pupation rates of late-stage larvae of 2 wireworm species,Melanotus depressus(Melsheimer) andLimonius dubitansLeConte, maintained on one of 4 soil substrates or on soil and germinating wheat were studied. AllM. depressuslarvae held for 21 mo on soil and germinating wheat underwent 2 or 3 larval ecdyses. Pupation occurred in May and June of the 1st year and March through May of the 2nd year. Dormancy occurred during the winter months. In the absence of germinating wheat, larvae showed a tendency towards retrogressive ecdyses. Although mortality was high,L. dubitanslarvae held under the same conditions for a period of ca. 11 mo appeared to show similar biological cycles. Larval ecdyses were observed 2 or 3 times and dormancy occurred during the winter months. No ecdyses were observed from December to February.L. dubitanslarvae, unlike those ofM. depressus, did not undergo regressive ecdyses and died from starvation within 6 mo.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.845

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Uptake and persistence of thiotepa (the sulfur analog of tepa) by pupae ofAedes aegypti(L.) was studied using gas chromatography. An average of 39.3±1.74 ng of thiotepa equivalents/pupa was found in samples taken shortly after treatment in 0.5% thiotepa for 3 hours. Newly emerged adults contained an average of 2.59 ng/adult, and in 24-h-old adults, there was<0.5 ng/adult. Competitive mating tests indicated that the sterile males were not severely debilitated, since the average competitiveness index was 0.94, or just below the value for equal competition. The extremely low residues in 24-h-old adults coupled with the vigor of the sterile males means that thiotepa-sterilized males present a means for the autocidal suppression ofA. aegypti.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.849

出版商:Oxford University Press    

年代:1976

数据来源: OUP

摘要:

Last-instar larvae of the pink bollworm,Pectinophora gossypiella(Saunders), leave the protective microhabitat provided by cotton fruit in a midday (1000–1400 h) circadian cutout rhythm and drop to the soil surface to search for a suitable pupation site. Before the plant canopy closes, larvae falling upon sunlit portions may encounter sufficiently high temperatures for periods long enough to render them ecologically dead. This time-temperature relationship, termed the Critical Thermal Maximum (CTM), was determined for 120 larvae at soil surface temperatures ranging from 45–68°C under field conditions. At temperatures below 50°C all but one insect survived a 10-min exposure, and most traveled at least one meter. At 51°C the CTM occurred within 2.5 min; at 65°C, it was reached within 0.33 min and the distance traveled was less than 0.2 m. A model developed by monitoring temperatures of larval cuticle with 2 thermocouple techniques showed that the CTM occurred when the insect cuticle reached 46–53°C.

ISSN:1754-5692    

DOI:10.1093/ee/5.5.853

出版商:Oxford University Press    

年代:1976

数据来源: OUP