ISSN:1754-5692    

DOI:10.1093/ee/17.4.621

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

The effect of prediapause temperature on diapause induction was investigated in a Michigan strain of the codling moth,Cydia pomonella(L.). A temperature of l7°C enhanced diapause induction, but higher temperatures averted or diminished the photoperiodic response. of the codling moth larva to diapause induction. The critical photoperiod (L:D) for 50% induction of diapause was 15:9, 14.4:9.6, 13.8:10.2, and 13.44:10.56 at 17, 22, 27, and 30°C, respectively. A method of estimating the diapause response of the codling moth to temperature is presented.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.626

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Cotton fruit from a given location on the plant were assigned to cohorts. The quantity and causes of fruit abscission in each cohort were monitored in three management systems. The proportion of fruit abscission caused by insect pests was largest in the early season cohorts, whereas physical stresses caused increasingly more fruit abortion in later cohorts. Plants tolerate insect-induced fruit abortion by retaining more of the surviving fruit within the same cohort. When a cohort was severely injured, fruit survivorship was increased in subsequent cohorts to compensate for the loss. Fruit production, abscission, and retention were normally distributed, and the patterns were consistent enough to suggest that a cohort technique may be a useful modelling approach.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.629

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Laboratory investigations of the gregarious squash bug egg parasitoidsOoencyrtus anasae(Ashmead) andO. sp. were conducted at 20.8, 23.0, and 26.6°C. Females of both species emerged with undeveloped ovaries. Oöcyte development proceeded during the preovipositional period (ca. 35 h at 26.6°C) but did not exceed half of the total fecundity at initial oviposition. Preovipositional periods, time to peak oviposition, and time to 75% oviposition were generally similar for both parasitoids at 20.8°C. However, reproductive responses differed at temperatures above 20.8°C. InO. anasae, oviposition occurred significantly earlier, and at a similarly higher rate, at 23.0 and 26.6°C than at 20.8°C, whereas significant changes in preovipositional and ovipositional biology ofO. sp. occurred only after an increase from 23.0 to 26.6°C.O. sp. had a significantly higher fecundity and longer ovipositional period at each temperature than didO. anasae.Mean fecundities did not change significantly with increasing temperature. Both parasitoids had an unusually long postreproductive period (ca. 1 mo) and a longevity of 40 to 50 d. At 26.6°C,O. sp. had higher gross and net reproductive rates thanO. anasae.However,O. anasaehad a shorter generation time (21.4 versus 23.8 d) and higher innate capacity for increase (0.146 versus 0.134).

ISSN:1754-5692    

DOI:10.1093/ee/17.4.636

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Field tests conducted in a relict prairie using sticky traps baited with a broad range of adult diabroticine attractants showedDiabrotica cristata(Harris) shares some chemosensory responses with bothD. barberiSmith and Lawrence andD. virgifera virgiferaLeConte.D. cristatawas attracted to estragole, β-ionone,para-methoxycinnamaldehyde, and a mixture of trimethoxybenzene, indole, and cinnamaldehyde (=TIC mixture) (attractants for adults ofD. virgifera virgiferain corn tests), as well as eugenol, isoeugenol, and cinnamyl alcohol (attractants for adults ofD. barheriin corn tests). Several of the active compounds, such as cinnamyl alcohol and β-ionone, are structurally distinct from the previously described eugenol-type attractants forD. barberiandD. cristataand represent new semiochemicals for the genus. In the prairie trials,D. barberiadults were anomalously attracted to two lures (estragole and the TIC mixture) that were not active in corn evaluations.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.644

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

In previous mark-recapture studies, laboratory-reared male gypsy moths,Lymantria dispar(L.), tended to arrive at pheromone sources 1–3 h later than feral males. In this study, laboratory-reared male pupae were exposed to five different temperature regimes, and the resulting adults were tested in an actograph at 25°C. Males that had been held at lower temperatures as pupae became active earlier than males that had been held in warmer treatments. In subsequent mark-recapture trials, males from all treatments were captured at pheromone sources earlier on warm days than on cool ones; however, on any given day, males from lower pupal temperature regimes were captured consistently earlier than males from warmer regimes. Temperature-mediated programming provides a potential means of synchronizing activity rhythms of sterile males with those of wild males in target populations.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.649

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Eurosta solidaginis(Fitch), the goldenrod gall fly, and its suite of predators and parasitoids provide an excellent system for the study of the dynamics of prey species and their enemies. The object of this study was to discover the effects of gall and quadrat characteristics on the fate of galls, and to assess the impact of each mortality source onEurostasurvival. Galls on goldenrod,Solidago altissima, in two large (700 m2) plots were followed through three field seasons (1982–84). Gall characteristics (diameter and height) and goldenrod cover were recorded as well as the eventual fate of each gall's inhabitant. A fertilization experiment was conducted to determine whether galls were more likely to be formed on healthier host plants. Five sources of mortality were examined: early larval failure, parasitism from either of two chalcid parasitoids,Eurytoma obtusiventris(Gahan) orEurytoma gigantea(Walsh) (Hymenoptera: Eurytomidae), predation by mordellid beetle larvae, and predation by birds. Characteristics of quadrats (number ofSolidagostems per quadrat and physiological condition of plants in the quadrat) were not reliable predictors of gall density within quadrats. Gall diameter is the only gall characteristic that reliably indicated fate. All predated or parasitized galls were smaller than those of survivors, with the exception of those predated by birds, which were significantly larger. Early larval death and predation by mordellid beetles caused the greatest mortality; however, mortality from birds probably has the most potential for population regulation.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.654

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Densities of mosquito larvae were compared by dipping in four habitat categories of Carver County, Minnesota wetlands. Eighteen species of mosquitoes from six genera were collected. Faunal compositions among study sites were similar; 33% of the sites produced 62% of mosquitoes collected. Of the 103,547 culicid larvae, 88% wereAedes vexans(Meigen). Density ofA. vexanswas highest in two habitat categories, both occupied by reed canarygrass,Phalaris arundinacea(L.). If this association prevails on a regional basis, mosquito control actions forA. vexansshould be directed at areas occupied by reed canarygrass.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.660

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Competition tests were carried out in the laboratory between the parasitic waspsTelenomus ullyettiNixon andTrichogrammatoidea luteaGirault on eggs of the bollwormHeliothis armiger(Hübner). In most cases when a freshly laidHeliothisegg was multiparasitized byTrichogrammatoidea luteaandTelenomus ullyetti, regardless of which species parasitized it first, the aggressive mandibulate larva ofTelenomus ullyettiwith its large sickle-shaped mandibles eliminated the larvae ofTrichogrammatoidea lutea.Temperature played a major role when populations of both species were forced to compete at different temperatures, relative humidities, and photoperiods on a limited resource.Trichogrammatoidea luteapopulations always won at 28°C, 50%RH, and 14:10(L:D) photoperiod, andTelenomus ullyettiat 22°C, 70%RH, and 10:14. At an intermediate range of 25°C, 60% RH, and 12:12 photoperiod, no advantage was shown by either species, and the outcome was probably due to chance.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.664

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Analysis of rawfiber content of balsam fir,Abies balsamea(L.) Miller, needles in conjunction with laboratory-reared larvae of spruce budworm,Choristoneura fumiferana(Clemens), during the 1985 growing season indicated significant variations in the quality of food available for consumption by the insect. Two consecutive years of defoliation as well as poor drainage were directly related to higher rawfiber content of the current year's foliage which, in turn, caused a decrease in pupal weight, larval development rate, and survival.

ISSN:1754-5692    

DOI:10.1093/ee/17.4.671

出版商:Oxford University Press    

年代:1988

数据来源: OUP