摘要:

The ability of honey bees,Apis melliferaL., to transfer pollen within the hive through contact with nestmates was tested. In almost all cases, bees acquired pollen from nestmate contacts. Pollen viability was tested by pollinating self-incompatible apple blossoms with treated bees. The contribution of in-hive pollen transfer to cross-pollination and fruit set in apple is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.723

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Abundance of the Colorado potato beetle,Leptinotarsa decemlineata(Say), was compared on cultivars of potato that differed in time to maturity (persistence), foliar biomass, and foliar concentrations of N. Longer-season cultivars produced more (although not consistently significant) foliage than shorter-season cultivars. Foliar concentrations of N were higher in most longer-season cultivars than in shorter-season cultivars. Abundance of beetles was not significantly different among most cultivars on most sample dates. Beetle abundance was significantly positively correlated with cultivar persistence, foliar biomass, and foliar N concentration. Multiple regression techniques indicated that foliar N was a better predictor of beetle abundance than foliar biomass.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.726

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Effects of age, dosage, starvation, crowding, and addition of 3-pentanone on response of the maize weevil,Sitophilus zeamaisMotschulsky, to a mixture of its male-produced aggregation pheromone (R*, S*)-5-hydroxy-4-methyl-3-heptanone, and theR*, R*diastereomer, were examined. Weevils ≤1 week old were attracted to pheromone, whereas 8- to 10-week-old weevils were significantly repelled by the pheromone. Weevils 1–2 days old responded to synthetic pheromone over a 1,000-fold range of doses. Starvation significantly improved response of young weevils to the pheromone, but had no effect on response by 10-week-old weevils. A trend toward better response under high-density conditions was observed in 1- to 2-day-old weevils, but not 10-week-old weevils. Males 1–2 days old were attracted to 3-pentanone, and its addition to the pheromone elicited a greater response by both sexes than response to either compound alone. Weevils 10 weeks old were strongly attracted to 3-pentanone when they had been starved. Function of the pheromone in colonization of exploitable food sources is discussed.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.733

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

The role of aggregation in mediating the ecological parameters that influence survival and development in first-instar southern green stink bug,Nezara viridula(L.), was examined. Aggregated nymphs were able to survive and develop more rapidly than isolated nymphs at low relative humidities. Aggregation appeared to facilitate intake of atmospheric water and protect against desiccation. An acceleration of development in aggregated nymphs was observed at low temperatures. It was confirmed that first instars do not feed, so aggregation had no role in nutrient intake. Aggregation apparently does not function as a means of contacting essential symbiotes. Adherence to a substrate was facilitated by aggregations of up to 10 nymphs, at which point aggregation became multilayered. Aggregated nymphs suffered less predation byPodisus maculiventris(Say) andSolenopsis invictaBuren. Individuals as well as groups of nymphs were unpalatable toHippodamia convergensGuérin-Méneville.Monomorium minimum(Buckley) apparently learned nonpreference of first instars whileTertamorium guineense(F.) andPheidole dentatumMayr were undeterred from foraging for nymphs over time.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.739

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

North temperate bumble bee colonies produce workers for the first part of the summer, then, at some point, switch to rearing only reproductives. The first occurrence: of males and gynes (new queens) of one bumble bee (Bombus flavifrons) was used to estimate when the reproductive switch point occurred in colonies distributed among 20 discrete subalpine meadows. Occurrence of reproductives in meadows was correlated with forager and flower abundance: males and gynes appear earlier in meadows with high forager and flower densities. While males were observed in each of the 20 meadows, gynes occurred. in only 15. The five meadows where gynes were not observed had lower flower densities: and supported significantly fewer foragers relative to meadows producing gynes. Differences among meadows in phenological patterns of flower availability were not related to the temporal occurrence of reproductive switch points.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.750

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Biotype C greenbug,Schizaphis graminum(Rondani), reproduction was studied on resistant and susceptible winter wheat (Triticum aestioumL.) genotypes grown under four levels of simulated drought stress, Water potentials of 0, −3, −6, and −9 MPa in the root medium were obtained by addition of polyethylene glycol (PEG) (M, = 1,000) to the hydroponic nutrient solutions. Wheat plants and greenbugs living on the solutions absorbed PEG, but a toxicity study of PEG in artificial diet showed that greenbug fecundity and survival was not diminished by concentrations normally encountered during this aphid/plant interaction study. The intrinsic rate of greenbug population growth (rm) decreased with increasing stress on both genotypes, but was higher on the susceptible ‘Sturdy’ than on the resistant genotype ‘OK 80268’, Although generation length was unaffected by stress, greenbugs on ‘Sturdy’ had shorter generation lengths than on ‘OK 80268’. For no variable was interaction observed between genotype and stress level, indicating that the level of resistance of ‘OK 80268’ relative to ‘Sturdy’ was maintained during drought stress. Stress reduced greenbug longevity, but host genotype had no effect. Reduced longevity seemed 1:0 be the major cause of reducedrmvalues during stress for ‘Sturdy’. Reduced fecundity and mean offspring per reproductive day contributed most to stress-inducedrmdeclines in ‘OK 80268’. Reduced generation length, prereproductive period, mean reproductive period, and greater mean offspring per reproductive day were apparently the major factors causingrmvalues to be higher for ‘Sturdy’ than ‘OK 80268’.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.756

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Feeding rates of first-instar, second-instar, and adult femaleScirtothrips citri(Moulton) at 20, 24, 28, 32, and 36°C were compared based on the passage of14C-labeled inulin through the digestive tract. For all temperatures, second instars ingested the most followed by adult females and first instars. Second instars also were more sedentary on the feeding surface and probably made more feeding punctures through the feeding membrane. Within life stages, first and second instars increased their feeding rate to an optimum temperature of 29–30°C and decreased their feeding rate at higher temperatures, whereas adult females increased their feeding rate over the entire temperature range. Results suggest that second instars are likely to cause the most scarring to citrus fruit.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.763

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Two commercial warehouses containing farmers stock peanuts were used to demonstrate ability ofBracon hebetorSay (Hymenoptera: Braconidae) andXylocorts flavipes(Reuter) (Hemiptera: Anthocoridae) to suppress field populations ofCadra cautella(Walker) (Lepidoptera: Pyralidae) andPlodta interpunctella(Hübner) (Lepidoptera: Pyralidae). One warehouse (treatment) containing peanuts with only traces of malathion residues received periodic releases ofB. hebetorandX. flavipesthroughout the storage period from 5 October 1983 to 3 January 1984. The control warehouse received no natural enemies but contained peanuts conventionally treated with malathion. Moth populations in the treatment warehouse were 54–83% smaller than populations in the control warehouse throughout the storage period. Also, peanuts in the treatment warehouse sustained less insect damage during the storage period. Approximately 324,000B. hebetorand 191,000X. flavipeswere released.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.767

出版商:Oxford University Press    

年代:1986

数据来源: OUP

摘要:

Betula pendulaRoth is a popular ornamental tree in northern California, which frequently hosts populations of four leaf-feeding aphid species. Differential aphid species distribution on occasional birch trees led to the identification ofBetula pubescensEhrhart, a closely related species, planted amongB. pendula.Spring sampling demonstrated thatCalaphis flavaMordvilko occurred predominantly onB. pubescenswhileBetulaphis brevipilosaBörner,Callipterinella calliptera(Hartig), andEuceraphis betulae(Koch) were more abundant onB. pendula.C. callipteraandE. betulaewere rarely found onB. pubescens, whereasC. flavapopulations constituted 22% of the aphid fauna onB. pendulawhen trees of the two species were adjacent.B. pubescenshosted a larger total aphid population as well as abundant leafhoppers. Honeydew presence on lower canopy leaves of both tree species was positively related with aphid density.

ISSN:1754-5692    

DOI:10.1093/ee/15.3.771

出版商:Oxford University Press    

年代:1986

数据来源: OUP