摘要:

Laboratory studies with an introduced parasitoid,Aphelinus asychis(Walker) (Hymenoptera: Eulophidae), and one of its hosts,Schizaphis graminum(Rondani) (Homoptera: Aphididae), were conducted during the spring and summer of 1972 to determine the number of greenbugs fed upon daily by the parasitoid, number of aphids parasitized daily, preferred mummification site, daily emergence rate of the parasitoid from the mummies, sex ratio of the emergent, and longevity for the parasitoid. A total of 608 aphids was fed upon by the 20 parasitoids. A total of 4655 mummies was formed for the 20 parasitoids of which 1967 were found on the leaves, 1200 on the stems, 121 in the whorls, 172 on the sand covering the soil, and 114 on the containers. Parasitoids emerged from approximately 81% of the mummies, and approximately 56% of these were females. Mean longevity for the 20 parasitoids was 23.4 days.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.549

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

(Z)-9-tricosente (muscalure) was evaluated as an attractant forMusca domesticaL. in the field in paired tests with different types of traps; panels painted with adhesive, flypaper strips, sugar bait in pans, and electric grids. The addition of muscalure (0.5–100 mg/trap) increased the numbers of flies caught by these traps by 3.4, 2.8, 7.0, and 12.4 times, respectively. Several kinds of box traps were ineffective. Muscalure-baited traps caught about equal numbers of males and females in the field in contrast to the lahoratory, where only males were attracted to muscalure in olfactometer studies.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.555

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Populations ofChromaphis juglandicola(Kaltenbach) and its natural enemies were assessed weekly during the growing season in 1969 and every 4 days in 1970. A parasite of the aphid,Trioxys pallidus(Haliday) (Aphidiidae: Hymenoptera), from Iran, was released and became established in the study area in 1969, but it did not affect the abundance of the aphid during that season. Large numbers of mummies overwintered, and the normal peak in aphid numbers in spring 1970 did not occur. Aphid numbers remained at levels about 0.01–0.001 of those in previous recorded years. An experimental release of aphids and use of a biological check method demonstrated that the parasite was responsible for the maintenance of the aphid at low numbers. The same tests showed that selective predation of parasitized aphids by the Argentine antlridomyrmex humilis(Mayr), presents a serious threat to continued control of aphid outbreaks by the parasite where ants are present. The rapid increase in the artificially induced outbreak of aphids indicated that it was not high temperatures that previously kept aphid numbers low in summer, but leaves made unacceptable by sooty mold and debris from the spring peak of aphid numbers.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.561

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Populations of wasps,Vespulaspp., on a 22-acre peach orchard near The Dalles, Oregon, were successfully depressed during the summers of 1969 and 1971 with traps containing the highly potent specific lures, 2,4-hexadlenyl butyrate or heptyl butyrate placed around the orchard' periphery. Moreover, the yellowjackets, mostlyVespula pensylvanica(Saussure), were reduced below troublesome levels within four days after the traps were placed. In 1969 about 200,000 wasps were captured in 114 carton traps and four large Malaise traps; in 1971 about 65,000 wasps were taken in seventy 87-oz (2.5-liter) plastic-container traps.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.569

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Foraging honey bees,Apis melliferaL., were captured at sample plots in a 65.2- hectare alfalfa,Medicago sativaL., field, tagged with color-coded, ferrous metal tags, and released. Distribution of these foragers was determined by recapture of tags by magnets at the entrances of 504 hives distributed in 29 apiaries within the field. The mean distance that bees flew was 198 meters for nectar and 240.3 meters for pollen.The nectar sugar concentration averaged 37.0% in the morning and 47.7% in the afternoon. Alfalfa pollen was totally absent in pollen samples trapped at hive entrances. The mean pollen collection (five days) was 247.5 and 189.6 grams per colony for Hy-Queen and standard stock, respectively, but the differences were not significant. The orientation of hive entrances (north or south) had no effect on the number of bees foraging on alfalfa.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.573

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The known differences in response byDendroctonus pseudotsugaeHopkins to its pheromone 3-methyl-2-cyclohexen-1-one (MCH) correspond with differences in concentration of the substance. When combined with other pheromones ofD. pseudotsugaeand host-plant volatiles, a low concentration of MCH elicits increased arrestment and stridulation of males and increased flight attraction of both sexes, whereas a high concentration of MCH inhibits the normal positive response of both sexes to these other pheromones and host plant volatiles. Since differential release of MCH apparently occurs during natural beetle behavior, these effects are suggested as multiple functions of the pheromone.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.579

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Periodic swarming ofCryptotermes brevisWalker was observed in late May and early June from 1968 to 1971, but no fall swarms were seen. Seasonal swarming apparently was related to rainfall, although daily swarming was not. The phenomenon was crepuscular, with peaks occurring about 30 minutes after sunrise and 80 minutes after sunset. Daily swarming did not seem to be related to wind or tides, but appeared to correlate with daily fluctuations of temperature, humidity, and barometric pressure. Observed light-source preference was for sunlight, ultraviolet, and incandescent, in that order. Maximum light intensity in the vicinity of actively swarming alates was 0.05–3 foot-candles. The sequence of swarming behavior included: departure from colony, dispersal flight with positive phototaxis, landing and substrate investigation, dealation, negative phototaxis, and pairing, which included a tandem behavior. Calling behavior also was observed. Dealation was nearly instantaneous. Tandem behavior of male behind female was consistent for 10 observations. Swarming was short-term dispersal rather than long-range flight. Maximum observed flight height and duration were 30 feet and three minutes, respectively.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.587

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Chemicals utilized by insects to foster host-parasite relationships (potentially useful for suppression of insect pests in an ecologically acceptable manner) were found in moth scales ofHeliothis zea(Boddie) and shown to directTrichogramma evanescensWestwood to eggs ofH. zea, which it then parasitized. Four chemicals comprising the major portion of the active principle in moth scales were isolated in pure form by column and gas chromatography and shown by gas chromatographic and mass spectrometric analysis to be docosane, tricosane, tetracosane, and penetacosane. The most active chemical, tricosane, elicited significant orientation and stimulated parasitization in both laboratory and small-field tests.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.593

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Studies on the effect of humidity on longevity ofCryptotermes brevis(Walker) revealed that groups lived longer than isolated individuals. Average longevity (50-day test) was 23.9 days for groups of 10 and 15.7 for isolated pseudogates when held over salt solutions in individual desiccators (5–96% RH, 25±1°C) to stabilize humidities. Average maximum longevity (122-day test) was 44.0 days for groups of 10 and 23.3 days for isolated pseudogates when held over sulfuric acid solutions (9–98% RH, 25± 1°C). Pseudogates generally lived longer at high humidities (87–98% RH) but sometimes showed temporary symptoms of water poisoning. Altruistic behavior of proctodeal and stomodeal feeding was prevalent in pseudogates at low humidities (5–7% RH).Humidity gradient preference investigations revealed a clumping behavior that was intensified in darkness. The minimum number of pseudogates required to demonstrate clumping was between five and 10. Preconditioning three hours in stabilized desiccating environment (9–11% RH) elicited pseudogate movement toward increased humidity (87–98% RH).

ISSN:1754-5692    

DOI:10.1093/ee/2.4.597

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Porthetria dispar(L.) males exhibiting pheromone orientation or searching behavior may be recognized by slow, slightly zigzag forward flight, with body held at an angle of roughly 45° to the horizontal plane and antennae directed up and forward. The mean search time for males searching alone at a natural pheromone source was 20.52±3.88 seconds; then males ended searching behavior. After termination of searching behavior, males held the body more horizontally, and forward flight was direct, rapid, and usually up or across the path of wind until they were lost from sight. Two males at a natural sex pheromone source touched wing tips in a mean time of 4.38±1.01 seconds of arrival of the second male. Searching behavior was terminated by rapid wing touching within two seconds in one or both males in 86 percent of the contacts.The evolutionary significance of this aggressive competition may be that it tends to disperse males from dense to sparse populations, thereby increasing the chance of males mating with isolated females, which have greater reproductive potential than females from dense populations.

ISSN:1754-5692    

DOI:10.1093/ee/2.4.603

出版商:Oxford University Press    

年代:1973

数据来源: OUP