摘要:

Annual and perennial plants differ in several physiological and life-history aspects such as rates of photosynthesis, respiration–transpiration, and growth, as well as allocation of resources. Possible consequences of these differences on herbivore growth were evaluated experimentally in pairwise comparisons using the aphidRhopalosiphum padi(L.) and a range of annual and perennial temperate-region grass species.R. padigrowth on annual wild barley (Hordeum) species was as good or better than on a barley cultivar. This contrasts with earlier studies in which aphid growth on perennial barleys was found to be much reduced. Aphid growth on annualAlopecurus, Anthoxanthum, Briza, andBromusspp. was higher than on perennial species of the same genera. However, no differences regardingR. padiperformance were found between annual–perennial species of the generaAgrostis, Cynosurus, Lolium, Phleum, andPoa. It is suggested that the resource-availability hypothesis is of no relevance for the observed relationships and that within Gramineae biochemical and/or structural plant traits are of greater importance forR. padiperformance.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.149

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

(Z)-154e161decen31 acetate(Z9–14:Ac) and (Z)-9-tetradecen-1-ol (Z9–14: OH) were identified as sex pheromone components of Dioryctria resinosella Mutuura. Sticky traps baited with 30 μg of Z9–14:Ac in rubber septa were attractive to males, and in some tests the addition of 5% of theE9 isomer enhanced catch. Addition of Z9–14:OH to these acetates did not increase catches, but in combination with Z9–12:Ac, the resulting four-component lure caught significantly more males than did Z9–14:Ac alone. Baited traps at the treetops caught significantly more moths than traps at the mid crown or lower crown (1.8 m above ground) levels. The seasonal flight ofD. resinosella, as indicated by catches in pheromone-baited traps, was prolonged. Flight started in mid-July, peaked in mid-August, and continued well into September. SomeDioryctria disclusaHeinrich andD. banksiellaMutuura&Munroe were also captured.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.154

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Electroantennogram responses of black cutworm,Agrotis ipsilon(Hufnagel), moths were measured for volatiles from flowers of 11 species of spring-blooming plants and 14 species of summer-blooming plants. Electroantennogram responses to the flower volatiles ranged from 0.17 to 0.99 mV. Field observations indicated that flowers of some of the tested plants were highly attractive to both male and female black cutworm moths and to other noctuid adults. Flower volatiles from blooming plants observed to be attractive to black cutworm adults in field situations also elicited relatively higher electroantennogram responses.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.162

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Five natural and semisynthetic Iimonoids and a synthetic model of Iimonin were tested against fifth instar fall armyworms,Spodoptera frugiperda(J.E. Smith). Antifeedant activity was absent in both deoxylimonin and tetrahydrolimonin, demonstrating the necessity of the furan system and epoxide group for activity. A synthetic model that incorporated the furan system and epoxide group demonstrated activity higher than the parent compound, Iimonin. Epilimonol was equal in antifeedant activity to Iimonin, indicating that the addition of a hydroxyl to the 7 position of the B-ring did not increase or reduce activity. Nomilin was the most active of the Iimonoids tested. A feeding deterrent simulation experiment indicated that the mode of action of the active Iimonoids was feeding deterrence.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.167

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

Toxorhynchites splendens(Wiedemann) larvae were raised in fresh water and fed one of four regimens ofCulex quinquefasciatusSay larvae, orAedes aegypti(L.) larvae ad libitum. The four regimens ofC. quinquefasciatuswere ad libitum, two prey per day during developmental days 1–10, two prey per day during days 10 through pupation, and two prey per day through pupation. Reproductive rate of the resulting adults was compared among all treatments. Higher reproduction rate was significantly correlated with higher weight at pupation, but weight at pupation was dependent on the rate of food ingested only during the final instar. Adults from larvae fedA. aegyptiad libitum oviposited fewer eggs than those receivingC. quinquefasciatuslarvae ad libitum during fourthinstar development. Daily rates of egg production were higher in all groups receiving ad libitum prey in the fourth instar than in those receiving two prey per day during the fourth instar. Larval development at a rate of two third-instar prey per day was as long as 64 d, whereas larvae given prey ad libitum, required no more than 22 d from egg hatch to pupation.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.174

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

The potential of Africanized honey bees,Apis melliferaL., to survive the cold temperatures and confinement of winter was studied at 4,100m above sea level in the Andes of Venezuela. The first experiment was conducted through the rainy-season “winter” of 1986 using Africanized (A) and European (E) colonies. In 1986, temperature conditions only rarely allowed honey bee Right. Under these conditions, 13 of 14 A colonies died within 18 wk compared with 4 of 15 E colonies. In 1987, European × Africanized (E × A)hybrid colonies were included in a larger experiment with treatments with various initial adult and brood populations. Higher maximum temperatures during this second experiment allowed worker Right almost daily; colonies in one treatment were confined with screens to test the published hypothesis that Right from A colonies during cold weather causes bees to leave their hives and die, causing the colonies to dwindle. All screened A colonies had died by week 10, while screened E and E × A colonies were alive through week 14. In treatments involving free-flying colonies, there were fewer differences between bee types in colony survival, size, brood production, final adult population, or food consumption. E × A colonies had intermediate values for most traits, suggesting that any differences will be reduced with hybridization as Africanized bees expand their range into areas with high-density populations of European bees.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.183

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

In standardized laboratory bioassays, soluble protein extracted fromBacillus thuringiensisHD-290-1 was toxic to early larval instars of cottonwood leaf beetle,Chrysomela scriptaF. (Chrysomelidae: Coleoptera) and forest tent caterpillar,Malacosoma disstriaHübner (Lasiocampidae: Lepidoptera) but was not toxic to first instars of fall webworm,Hyphantria cunea(Drury) (Arctiidae: Lepidoptera). Trypsin-digested toxin was slightly more toxic than undigested protoxin to cottonwood leaf beetles and forest tent caterpillars. Susceptibility of cottonwood leaf beetles decreased with increasing age (2- and 4-fold decrease in LC50from first instars to third instars with protoxin and toxin, respectively). Adult cottonwood leaf beetle mortality did not exceed 30% when exposed to the highest dose of toxin tested (100 μg/ml for 96 h), but foliage consumption was decreased in a dose-dependent fashion. Adult beetles did not avoid leaf disks treated withB. thuringiensisextract in choice tests. These results are discussed with regard to genetic engineering ofPopuluswith the gene coding for this protein.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.190

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

The median lethal concentrations ofBacillus thuringiensisCry1A(a) toxin (Cry1A(a) = 0.2% of total protein) for second-instar spruce bud worm and first-instar fall webworm were 6 μg engineeredE. coliprotein extract (EPE)/ml diet, and 0.1 μg EPE/cm2of diet surface, respectively. The median lethal times were 8.4 and 2.8 d, respectively. Although second-instar spruce budworms were not killed rapidly, larval weight gain was decreased at sublethal concentrations and inhibited at higher concentrations of the toxin. Spruce budworm larvae preferred control diets to toxin-treated diets in choice tests. In contrast, first-instar fall webworm did not avoid toxin treated diets in choice tests. Spruce budworm larval survival was not affected significantly by most toxin concentrations when untreated diet was available (choice test), but larval weight decreased with increasing toxin concentration. Second-instar spruce budworm ingested toxic diets within 6 h of infestation, and the level of ingestion increased Significantly after 24 h. Preexposure to high concentrations of toxin-incorporated diet for 48 h did not affect ingestion of toxic diet. Spruce budworm larvae recovered from toxin upon transfer to control diet, but larval duration increased with the duration of initial exposure. Pupal weights were not affected, regardless of duration of exposure to toxic diet. These results are discussed with regard to development and deployment of trees engineered to expressB. thuringiensisCry1A(a) toxin and the evolution of behavioral and physiological resistance of insects toB. thuringiensistoxins.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.197

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

In Lincoln County, NE, cattle confinements were sampled weekly during the summers of 1983 (n= 5) and 1984 (n= 4) for pupal parasitoids and arthropod predators of house fly,Musca domestica(L.), and stable fly,Stomoxys calcitrans(L.). Parasitism of these flies increased through the field season, peaking in August and September. The overall rate of parasitism was significantly influenced by specific fly breeding habitats but was not Significantly influenced by confinement type or waste management efforts. In addition, parasitism of house flies was significantly different between years. The pteromalidsMuscidifurax zaraptorKogan&Legner andSpalangia nigroaeneaCurtis accounted for most of the parasitism of house fly pupae.Aleochara lacertinaSharp andS. nigroaeneawere the most abundant stable fly pupal parasitoids. Grass clippings, used as an artificial breeding habitat for stable flies, influenced the occurrence of parasitoids and increased the rate of stable fly parasitism. Adult stable fly populations peaked in late July 1983 and in late August 1984. House fly populations generally increased throughout the summer. Confinement type and waste management efforts influenced adult fly population trends. The staphylinidsPhilonthus americanusErichson andOxytelus sculptusGravenhorst were the most abundant insect predators found in this study.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.212

出版商:Oxford University Press    

年代:1993

数据来源: OUP

摘要:

A statewide survey of nine alfalfa-producing regions in Illinois was conducted during 1990 and 1991 to determine the distribution and abundance of two parasitoids,Bathyplectes anurus(Thomson) andBathyplectes curculionis(Thomson), that attack larvae of the alfalfa weevil,Hypera postica(Gyllenhal). Data suggest thatB. anurushas displacedB. curculionisin Illinois.B. anuruswas more abundant in the western counties of the state than in the eastern counties; however, the abundance ofB. curculionisdid not vary significantly among different regions of the state. A fungal pathogen,Zoophthora phytonomi(Arthur), was also detected in 12 of the 27 fields sampled and in 11 of 14 counties surveyed. Further research is needed to determine the effect of interactions among these biological agents in the regulation of alfalfa weevil populations in Illinois.

ISSN:1754-5692    

DOI:10.1093/ee/22.1.220

出版商:Oxford University Press    

年代:1993

数据来源: OUP