摘要:

Net fitness in spider mites, defined as the number of adult offspring per female, is a function of the number of eggs produced and the survival rates of eggs, larvae, protonymphs and deutonymphs. The relationships between fitness and its components were estimated in some laboratory environments. It was found that egg production overwhelmingly determines female fitness. Since the fitness components completely determine the net fitness, the relationship may be considered as a closed system of interacting components. A method of analyzing such a system is also introduced.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.1

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Six species of tetranychid mites were found feeding on almond foliage in the southern San Joaquin Valley of California. Two species, the brown mite,Bryobia rubrioculus(Scheuten), and the European red mite,Panonychus ulmi(Koch), were rare. The citrus red mite,Panonychus citri(McGregor), was present on the east side of the valley, annually renewing infestation on almond by ‘ballooning’ from the citrus of that area in spring and dispersing south and west on almond over a period of months. Most of theTetranychusspp. populations sampled were mixed populations consisting of 2 or occasionally 3 species. These 3 principal pest species were not uniformly encountered across the valley. The twospotted spider mite,Tetranychus urticaeKoch, was present in all areas of the valley and was the dominant species in lower elevation mid-valley orchards. The Pacific spider mite,T. pacificusMcGregor, was common or predominant in east and westside foothill orchards above 120 m in elevation and was rare in mid-valley orchards. The strawberry spider mite,T. turkestani(Ugarov and Nikolski) was not encountered in westside orchards and accounted for ¼ to ⅓ of theTetranychuspopulations sampled in mid-valley and eastside orchards.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.6

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Bradysia impatiens(Johannsen) females emit a sex pheromone that elicits male upwind flight in the male, evidently via a mechanism of optomotor-modulated anemotaxis. Maximal male wing fanning and upwind walking to female body extract occurs between 5 h before to one h after the initiation of scotophase on a 16:8 LD. Mated and unmated females appeared to have similar quantities of extractable pheromone. The mating sequence appears relatively stereotyped.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.10

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Male stable flies,Stomoxys calcitrans(L.), rested on prominent bright sunlit objects near their hosts. On mild days males were present on such objects (waiting stations) throughout the day with peak populations occurring early in the morning. On cool days, male activity was confined to midday. When a waiting station was coated with adhesive, 60% of captured flies were males. Of the females caught, 35–54% were unmated. Ca. 26% of the flies were engorged and ca. 37% had not had their first meal. Stable flies fed on the host throughout the day in mild temperatures, but ceased to feed when the temperature failed to exceed ca. 10°C. Males resting on waiting stations darted out after other flying insects and engaged them in aerial interactions. Observations of marked males indicated that some males maintained their positions several hours while other males remained only a few minutes and left their positions after aerial interactions with larger males. Males also encountered receptive females at the waiting stations. Males mounted females in the air or on the ground but copulation occurred on a perch. During the winter months, stable flies basked in the sun at the waiting stations and were able. to maintain internal temperatures up to 14.8°C higher than ambient temperatures. When internal temperatures reached 31–34°C flies were found at shaded resting sites.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.16

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Identification of the significant factors that affect codling moth pheromone trap catches is necessary for the establishment of standardized trapping procedures and optimal mass-trapping programs. Trap catches were higher when traps were placed toward the tops of apple trees and outside the canopy. Traps that were aligned parallel to the prevailing evening air movement caught more moths than traps aligned perpendicularly. As trap/tree density increased in a given area, the number of moths caught per trap decreased, but at a rate that was less than would be expected if the total catch of all the traps were the same for all densities. The total number of moths caught per plot increased as the trap/tree density increased. The two highest densities tested (1 trap/tree and 1 trap/2 trees) caught the most moths. These densities did not reduce the mating success of tethered females below that of females in an untrapped plot which suggests that mass-trapping in an orchard with a high population density of moths is not feasible as part of a pest management program.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.22

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Seasonal abundance and activity ofSitona hispidulus(F.) adults were monitored from June 1976 to August 1978 in alfalfa and red clover. A sharp rise in density followed by an equally sharp decline occurred during June and early July. Emergence from pupae occurred during June. Cumulative emergence data indicated that this increasing density was due to accumulation of the adults emerging from the pupae. Directional pitfall trapping indicated that the decline density was due to emigration of adults into the field borders by crawling. After this decline in density and the crawling activity stopped, the density remained about the same from late July through late August. This corresponded with the relative inactivity of the oversummering adults. From late August until late October the adults were active again, exhibiting crawling activity and a flight period. Directional pitfall trapping and sticky trapping indicated that movement, both into and out of the field, occurred during this period.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.27

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Two estimators of trends inDendroctonus frontalisZimmerman populations are evaluated. One estimator is brood increase ratio, R*, the brood beetles emerging per parent. The other is within-tree survival, S*, the brood beetles emerging per egg. The sampling distributions of R* and S* were studied using computer simulations. Both R* and S* are biased, always overestimating R and S, but S* is less biased and more consistent than R*. The distributions of R* and S* become less biased and more peaked as sample size increases.The validity and sensitivity of tests of hypotheses based on R* and S* are discussed. Because the distributions of R* and S* are not normal, the estimators should be used cautiously in tests of hypotheses that assume normality. Besides the statistical problems inherent in using R* and S*, there are problems in gathering sufficient data to calculate the estimators reliably. Complete dissection of bark samples and precise timing of sampling are vital.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.31

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Harvester ants,Pogonomyrmex owyheeiCole, irradiated with 3.5 kR to 268 kR of 137Cs gamma radiation, were maintained at simulated summer (27°C) and winter (7°C) temperature regimes. After thirty days, the cool series was warmed to 27°C and observed for mortality along with the warm series. Though mortality was delayed in the cool series, each series reached 50% mortality at similar rates.Because the harvester ant is extremely tolerant to radiation and experimental rates used far exceed possible environmental exposure, it is unlikely that ant colonies dwelling among low-level nuclear waste storage sites will be deleteriously affected by radiation. This species has the capability of tunneling to a depth well within the range of some buried waste. Since these harvester ants are potential transporters of buried waste, they should be considered as a biotic factor in radioactive waste management operations in semi-arid regions.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.39

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

The velvetbean caterpillar,Anticarsia gemmatalisHubner, did not survive the winter of 1978–79 under experimental conditions in south Mississippi. Pupae held at 9°C or in overwintering field cages died before spring. Moths were not observed in spring in cages placed over wild hosts artificially infested with larvae or in emergence traps placed over areas known to be heavily infested with larvae during the previous fall. Moths were collected in black light traps in April 1978 but not in April 1979. Larvae were not collected on soybeans or wild hosts until late July 1978. The trend in larval population build-up was similar on soybeans and wild hosts until soybean maturity. Larvae were present on wild hosts until December in 1978.The April and June (1978) occurrences of moths were associated with air circulation patterns which may have carried them to Mississippi from south Florida or the Yucatan Peninsula.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.45

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Broom snakeweed,Gutierrezia sarothrae(Pers.) Britt. and Rusby, and the closely related threadleaf snakeweed,G. microcephala(DC.) A. Gray were sampled for root-feeding insects at 18 sites in Lea Country and two sites in Lincoln County, New Mexico, in 1978 and at ten sites (nine sites revisited) in Lea County and one site in Guadalupe County in 1979. Of the 600 plants collected in 1978 nearly 60% of the dead or nearly dead plants (76–100% dead material) above 15.2 cm in height contained root borer holes. Less that 15% of the plants 15.2 cm or less in height, whatever their health classification, contained borer holes. Root borer holes were thus most closely correlated with taller, older, unhealthy plants. The longhorned beetleCrossidius pulchellusLeCont appeared to be the major root borer in these populations. Most of the plants collected in 1979 were healthy seedlings and much less borer activity was seen.

ISSN:0046-225X    

DOI:10.1093/ee/10.1.53

出版商:Oxford University Press    

年代:1981

数据来源: OUP