摘要:

Fifty-five species of insects visited macadamia flowers in orchards in eastern Australia. Only two species, the social beesApis melliferaL. andTrigona carbonariaSmith, were common. Abundance ofT. carbonaria, but notA. mellifera, was significantly positively correlated with extent of surrounding eucalypt vegetation.A. melliferaandT. carbonariashowed no preference for heavily versus lightly flowering trees. Both bee species, but especiallyT. carbonaria, preferred outer racemes to shaded racemes, possibly reducing the effectiveness of these species as pollinators. Both bee species were present for the major period of macadamia flowering.T. carbonariaforaged for a mean of 7 h a day compared with 10 h forA. mellifera.Both species showed moderate annual variation in abundance at some sites. Four bird species were also observed feeding on macadamia flowers, they may playa role in pollination.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.91

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Egg hatch of blackheaded fireworm,Rhopobota naevana(H¨bner), was monitored in Wisconsin and British Columbia. In Wisconsin, hatch of overwintering eggs began during the last 2 wk of April, median hatch occurred during the first week of May, and hatch ended in late May. In British Columbia, hatch began in late March to early April, median hatch occurred in April, and hatch ended (except for one egg in both years that hatched in June) in late April in 1991 but extended into late May in 1992. Summer-generation eggs began hatching 2–7 d and completed hatch 6–15 d after oviposition in both regions. A linear spline model developed in Wisconsin predicted 50% hatch of overwintering eggs in Wisconsin to within ±5.5 d standard deviation. The model had extreme error in predicting hatch in British Columbia. A linear model predicted 50% hatch of summer-generation eggs in both Wisconsin and British Columbia to within ±1d standard deviation.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.101

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Clones of greenbug,Schizaphis graminum(Rondani), biotypes J and E were investigated for numerical increase and damage to eight small grains. The small grain cultivars were: ‘Triumph 64’ and ‘Dickinson 28A’ wheat; ‘Wintermalt’ and ‘Post’ barley; ‘Elbon’ and ‘Insave F. A.’ rye; and ‘Nora’ and CI 1580 oat. On the 18th d after infestation at 17:15°C and a photoperiod of 15:9 (L:D) h., J differed from E by a greater density per plant on ‘Post’, ‘Wintermalt’, and CI 1580 but had a lower density per plant on ‘Nora’, ‘Dickinson 28A’, ‘Triumph 64’, ‘Insave F. A.’, and ‘Elhon’. The plant damage ratings after 21 d demonstrated clear differences between the greenbug clones. Differences among cultivar responses to clones remained the same at four different temperature and photoperiod regimes. ‘Dickinson 28A’ and ‘Post’ were the most consistent in distinguishing greenbug clones E and J. Damage ratings were correlated with the numbers of aphids per plant on specific cultivars. Clone J from the barley growing region of Idaho had greater densities and caused more damage than clone E on the barley cultivars, but clone J had fewer progeny and caused less damage than clone E on the wheat and rye cultivars.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.108

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The larvae ofAsphondylia rudbeckiaeconspicuaOsten Sacken develop in ovoid chambers in polythalamous summer galls on the flower heads and apical meristems ofRudbeckia laciniataL. (Asteraceae). Three wasps are known to parasitize the gallmaker;Rileya americanaGirault,Torymussp. nearasteridis, andT. advenusO.S. In the current study we addressed three questions. Are gallmakers that occupy deep gall chambers less likely to be parasitized than those in shallow gall chambers? Does chamber depth vary with the number of chambers? And finally, does larval survival vary with the number of larvae per gall? At the three populations studied, unparasitized gallmakers occupied the deepest chambers, followed byR. americana, then byTorymusspp. Mean chamber depth increased with the number of chambers per gall at all sites, which raised the possibility that individual vulnerability to parasitoid attack could vary with the number of gallmates through the group effect on chamber depth. In one population, the rate of parasitism byTorymusspp. was highest in galls with an intermediate number of hosts. Thus, survivorship for the gallmaker at this site can be explained by the responses ofTorymusspp. to the number of chambers per gall. Patterns of parasitism forRileyawere marginally related to chamber number in another population.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.115

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Effects of age, mated status, provision of food, and temperature on calling behavior under field conditions by females ofLambdina fiscellaria fiscellaria(Guenée) were examined. Eighty to 100% of virgin moths aged 1 to 7 d called for a mean total of 3.3 to 6.7 h during the night in bouts averaging 0.6 to>3 h; calling did not occur during the day. Marking, a behavior characterized by the rubbing of fully extruded terminal abdominal segments against the substrate, was exhibited by virgin moths for brief periods in the afternoon and for total durations averaging 25 min to 4 h at night. Old moths called longer and in fewer bouts and marked less often than young moths. Mated moths usually did not call but, like virgin moths, did exhibit erratic marking patterns early in the scotophase. The provision of goldenrod flowers had little effect on marking or calling. When temperatures were<10°C, the percentage of moths calling rose, calling bout length and total time spent calling increased, the onset time of calling shifted to earlier in the scotophase, and the amount of marking decreased.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.122

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Oviposition site preferences of two predatory mosquitoes,Toxorhynchites splendens(Wiedemann) andToxorhynchites rutilus rutilus(Coquillet), were compared in the laboratory using eight oviposition cup colors affixed 0 and 1 m from the cage floor.T. splendensfemales preferred to oviposit in black containers. Secondary preferences were for dark red and brown rather than green, blue, orange, yellow, or white containers. Substantial oviposition occurred in containers of all colors except white and yellow. Over 96% of all eggs were deposited at ground level.T. r. rutilusfemales had a stronger preference for ovipositing in black containers but did deposit eggs in red, blue, and brown containers at ground level. More than 25% of all eggs were deposited 1 m from the cage Roorduring choice tests. Oviposition byT. r. rutilusrarely took place in containers painted white, yellow, orange, and green. On the basis of these results,T. splendensappears to be the better candidate for mosquito control in heavily urbanized areas where discarded containers on the ground serve as developmental habitat for pest mosquitoes.T. r. rutilusappears to be the better candidate for treeholes. It is suggested that consistent means of comparing the characteristics ofToxorhynchitesspecies for biological control programs be developed.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.130

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

Delphastus pusillus(LeConte), an indigenous coccinellid predator of whiteflies, including sweetpotato whitefly,Bemisia tabaci(Gennadius), feeds on all stages of whiteflies. In laboratory tests, fourth-instar and adult femaleD. pusillusexhibited a marked tendency to avoid fourth-instarB. tabaciparasitized by the aphelinid endoparasitoidsEncarsia transvena(Timberlake) andEretmacerussp. nr.californicusHoward in favor of unparasitized whiteflies. The age of the parasitoid within the whitefly influenced the extent of the avoidance. Whiteflies with first-instar parasitoids were not avoided, but those containing third instars and pupal parasitoids were significantly avoided. The presumed causes of the avoidance include parasitism-induced hardening of the whitefly cuticle and introduction of air into the whitefly around maturing parasitoids.D. pusillusand parasitoids tend to attack different stages of the whitefly. This attribute increases temporal separation, enhancing the options for the use ofD. pusillusin pest management programs in conjunction with parasitoids.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.136

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

In 1989 and 1990, parasitism of the apple blotch leafminer,Phyllonorycter crataegella(Clemens), was assessed in 17 and 16 apple orchards, respectively, in Massachusetts to determine the effect of integrated pest management (IPM) practices that reduced pesticide use between early June and late August. In test blocks on each farm, broadcast pesticide applications for control of the apple maggot,Rhagoletis pomonella(Walsh), were replaced by use of either red spherical sticky traps on perimeter apple trees to intercept immigrating apple maggot flies or by applications of pesticides to perimeter apple trees. In either case, no insecticides or miticides were applied to the interior of test blocks after early June. Use of these methods was designed as second-stage IPM, and apple blotch leafminer parasitism under such management was compared with an adjacent block in each orchard using conventional pesticide tactics. Average parasitism of tissue-feeding apple blotch leafminer larvae across all orchards was slightly greater in the second and third host generations in blocks in which second-stage IPM practices were used than in conventionally managed blocks on the same farms. Most enhancement of apple blotch leafminer parasitism occurred in orchards in which traps were used to control apple maggot flies. Orchards in which perimeter-pesticide applications were made showed little or no difference in parasitism levels from those of full spray blocks. None of six orchard or insect variables examined (block size, ratio of interior trees to edge trees, nature of surrounding vegetation, number of pesticide applications per leafminer generation, density of tissue-feeding stage apple blotch leafminer mines, or percentage parasitism in the previous apple blotch leafminer generation) explained a significant proportion of the variation in parasitism seen among orchards and blocks in correlation analyses. Suppression of first generation apple blotch leafminer densities in 1990 was followed by lower average parasitism across orchards compared with 1989.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.140

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

The biology of the weevilCoelocephalapion aculeatum(Fall) and its specificity toMimosa pigraL. (Mimosaceae), a serious introduced weed in Australia and Thailand, were studied in a quarantine facility in Australia. Ninety-two plant species were screened, andM. pigrawas the only host that sustained a population ofC. aculeatum.Adults fed on developing and open inflorescences and oviposited mainly in buds of inflorescences of mid-to-late development. Larvae developed and pupated within these buds. Developmental time from egg to adult was 10–12 d. Field releases commenced in July 1991 in Thailand and in January 1992 in the Northern Territory of Australia.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.147

出版商:Oxford University Press    

年代:1994

数据来源: OUP

摘要:

A statewide survey indicated that the mermithid nematodeHeleidomermis magnapapulaPoinar&Mullens was widespread in California. The nematode occurred in many manure-polluted habitats where the insect host,Culicoides variipennis(Coquillett), was found, but was absent from two saline or alkaline habitats. Nematodes emerged from larvae ofC. variipennisbetween February and November. Field-collected, late-instarC. variipenniswere held individually to determine the extent of parasitism. Parasitism ranged from 0 to 69% in southern California. Hosts parasitized by a single nematode most commonly yielded females, whereas hosts harboring multiple nematodes yielded males. The sex ratio was 2.4 males per female. Only three of 5,308 adult midges were found to be parasitized.

ISSN:0046-225X    

DOI:10.1093/ee/23.1.154

出版商:Oxford University Press    

年代:1994

数据来源: OUP