摘要:

The relationship of temperature, moisture, and photoperiod was studied under laboratory conditions relative to termination of diapause inPectinophora gossypiella(Saunders). Field conditions occurring at Mesa, Arizona, for the midmonth periods of March, April, and May were simulated in environmental chambers, and diapausing larvae were subjected to these temperature conditions in both wet (contact moisture) and dry (ca. 50% RH) environments. Diapausing larvae were also subjected in constant-temperature cabinets to mean temperatures of the 3 monthly periods. Both studies indicated that conditions occurring during mid-April were most favorable for pupation and survival.Constant-temperature studies indicated that 13.9°C is below the threshold of development under both wet and dry conditions and that only under wet conditions is the 15.6°C temperature favorable. Temperatures of 17.8°C and 20.0°C were less favorable than 22.2°C under dry conditions for pupation and adult emergence, but little difference was noted between 20.0°C and 22.2°C under wet conditions, except for delayed pupation at the lower temperature.A limited study of photoperiod effects comparing a 14-h with a 10-h day indicated that a slightly higher rate of pupation occurs in the day-long regime. This was more evident under constant-temperature conditions than under fluctuating conditions.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.967

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The effects ofHypera postica(Gyllenhal) size, sex, and age on the productivity of its parasite,Microctonus aethiops(Nees) (Hymenoptera: Braconidae) were studied in the laboratory.Host size had no significant effect on the mean number of progeny or mean percent females produced per parasitoid. However, host mortality was significantly higher among the small hosts.Host sex had no effect on host selection by the parasitoid, nor was a differential mortality observed between male or female hosts.Host age was a factor in the production ofM. aethiopsprogeny. The majority of parasite larvae diapaused in 1- to 21-day-old host weevils, with the exception of those 7 days old. In the 7-day-old host, 28.5 of a mean 40.5 parasitoid larvae completed development without diapause. In 28- to 70-day-old hosts, with exception of those 49 days old, the majority completed development without diapause. In the 49- to 70-day-old weevils, significantly fewer eggs were oviposited by the parasitoids. This was attributed mainly to the weevils' reduced physical activity and feeding.Parasitization byM. aethiopscaused negligible mortality prior to parasite emergence in the 1- to 70-day-old weevils.The results suggest that physical development of the hosts' reproductive organs is not always an accurate index of its suitability for parasitoid development. In general, 28- to 70-day-old weevils were suitable for uninterrupted, nondiapausing development ofM. aethiopslarvae.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.971

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Haematobia irritans(L.), sterilized by irradiation with80Co, were released into a semi-isolated population in W Texas to determine the effect on the natural population. The initial releases (ratio of 10 sterile: 1 fertile insect based on prerelease data concerning adult emergence) caused a downward trend in reproduction. Continued releases caused a decrease in reproduction in excess of 98% during the last 3 weeks of the 16-week study, and control exceeded 70% for 10 weeks. However, when the sterile: fertile ratio dropped below 6: 1, the decrease in reproduction dropped below 90%.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.976

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Larvae, early and late (pharate) pupae, and adults ofDiatraea saccharalis(F.), were subjected to various constant high temperatures ranging from 35 to 43°C and fluctuating temperatures from 35–21 to 43–21°C, to evaluate effects upon survival and further development. Constant temperature was consistently more detrimental than fluctuating temperature, regardless of life stage. Late pupae were the least susceptible, and comparatively susceptible larvae and adults were considered to be the limiting stage in nature. Laboratory findings were compared with short-term daily in-the-field high temperatures of up to 46°C in Puerto Rico, and their significance to control efforts is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.981

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Larvae, early and late (pharate) pupae, and adults ofDiatraea saccharalis(F.) were subjected to various high temperatures ranging from 35 to 43°C and fluctuating temperatures from 35–21 to 43–21°C. Adults derived from the immatures and the heat–treated adults were outcrossed to normal partners to determine effects on mating success, fecundity, and fertility. Mating success of heat-treated adults was severely affected as length of treatment and temperature increased. Mating success of adults derived from treated larvae and pupae was only slightly affected. Fecundity was unaffected among females derived from treated larvae and pupae. Fecundity was lower in heat-treated adult females only after 96-h exposure, but age was a major factor. Fertility of males derived from heat-treated larvae and pupae, as well as treated adult males, was not affected. Females from larvae exposed to 39–21 and 36.5°C and higher temperature suffered substantial fertility loss. Among females derived from heat-treated pupae, all temperature levels caused some fertility loss, and early pupae females showed a higher degree of fertility loss than late pupae. Hatch of eggs, once fertilized, was not reduced.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.986

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The flashed mating signals of 22 species of Luciolinae in the generaLuciolaandPteroptyxare diagnostic aids to field identification, and indirect evidence suggests that information-coding parameters are similar to those of New WorldPhotinusspecies. A new element of potential coding significance, the intensity ratios of modulations within flashes, was revealed by the emissions of 3Pteroptyxspecies. In addition, a coding significance may explain the lengthy emissions composed of recurring modulation patterns in seemingly random fashion that are characteristic of males and females of 2 species. It is possible that the females ofLuciola obsoleta(E. Olivier) learn the luminescent repertoires of individual males. The evolutionary origin of some communicatively significant luminescent patterns may have been illumination flashes and glows, such as those presently observed in landing individuals. The mating protocols of Luciolinae fireflies vary greatly in complexity, from the very simple to the most complex yet found in luminescent organisms. Although mass synchronous flashing of fireflies is conspicuous and is associated with mating behavior, it probably is of little reproductive significance. This phenomenon may merely be the gross consequence of individual males synchronizing with their neighbors as they compete in small clusters for females on an extremely localized level.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.991

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

A comparative life-table analysis ofTrichoplusia ni(Hübner) populations on cotton in California revealed that, where predators were suppressed with properly timed applications of dimethoate insecticide, increases in larval survival ofT. nioccurred. When the populations of predators were allowed to reach density levels comparable to those in the nontreated control, survival rates forT. nilarvae did not differ significantly between nontreated plots and previously treated plots. The results suggest that predators, particularly adults and nymphs ofOrius tristicolor(White),Geoeoris pallensStål,Nabis americoferusCarayon, and larvae ofChrysopa carneaStephens, inflict a major intrageneration mortality onT. nilarvae on cotton, and that, when these natural enemies are suppressed, a secondary pest outbreak ofT. nican occur.Rates of parasitization and polyhedrosis ofT. nidevelopmental stages were not, in general, adversely affected by the dimethoate sprays. A nuclear polyhedrosis virus and an egg-larval parasite,Copidosoma truncatellum(Dalman), appeared to cause mortality which was density related. Two apparently new parasite records forT. niare recorded:Chelonus texanusCresson andPatrocloides montanus(Cresson).

ISSN:1754-5692    

DOI:10.1093/ee/2.6.1009

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

Acari and Collembola in soil from 3 differently treated adjacent areas—forest, clear–cut, and slash-burned—were sampled monthly for 1 year in the 2nd year after logging and slash burning. Samples were separated into 5 levels: litter, and four 225.8-cm2(35 in.3) soil layers, each 2.54 cm (1 in.) deeper than the preceding one. Organisms were extracted for 10 days in modified Tullgren funnels, preserved in ethanol at 4°C, and identified using published keys. Densities of organisms were transformed using log10X + 1, and subjected to an analysis of variance. No seasonal fluctuations were found in any of the 3 areas. There was no correlation of density with soil moisture,pH, or temperature. Vegetation in the logged area differed considerably from that in the burned area. Density of Acari, Collembola, and other arthropods was reduced by logging and further by slash burning. The population levels and diversity in both logged and burned areas were relatively high, indicating that neither treatment induced total mortality, and/or there was rapid reinvasion of treated areas. For the Cryptostigmata, the population reduction posttreatment became less with depth. Density of Astigmata, Prostigmata, Mesostigmata, and Collembola in the family Isotomidae in the litter and the first 2 levels of soil was progressively reduced by logging and slash burning, but in the 3rd and 4th soil levels, density was increased, indicating that migration to deeper levels or adaptation to conditions further below the surface had occurred.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.1016

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

The existence of a female sex attractant inArchips semiferanusWalker is demonstrated. Extracts of the abdomens of adult virgin females attracted male moths in a laboratory flight chamber and in the field. Males were attracted to the source of the pheromone in the flight chamber at a concentration range of 2 to 2×10−8female equivalents (FE). A range of 2×10lto 2×10−7FEcaught significant numbers of males in relation to blanks in the field traps. The best response obtained from males in the flight chamber and in a small field trap was at 2×10−2FE, whereas the optimum male response to the pheromone was elicited at 2FEwhen a larger field trap was used.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.1024

出版商:Oxford University Press    

年代:1973

数据来源: OUP

摘要:

An investigation of the toxic effects from single concentrated doses of 1-naphthyl (hydroxymethyl) carbamate, 1,5-dihydroxynaphthalene, or 1,3,5-trichlorobenzene demonstrated a marked increase in death of the embryos in eggs deposited from the 7th to 14th days after treatment ofBracon hebetorSay virgin females. Hatchability returned to control levels about the 15th day. Associated with poor hatchability was an increase in the proportion of embryos dying during cleavage (Stage 1 Death). This indicated the vulnerable cells of the ovariole sequence to be those undergoing mitosis, a finding consistent with the reports of damage to the mitotic apparatus by related compounds in other organisms. Egg production was decreased only slightly. The results were similar whether the females were injected with 1 of the agents or exposed to a residual deposit of it.

ISSN:1754-5692    

DOI:10.1093/ee/2.6.1029

出版商:Oxford University Press    

年代:1973

数据来源: OUP