摘要:

A trapping study was conducted in an apple variety block to determine if feeding green June beetles (GJB),Cotinis nitida(L.) (Coleoptera: Scarabaeidae), produce semiochemicals that induce their aggregation. Yellow baffle and funnel traps were baited with fruit only (ripe peach slices), three males and three females (no fruit), six males (fruit access blocked), six males (free access to fruit), six females (fruit access blocked), and six females (free access to fruit). Traps were arranged in a Latin cube design (six row × six column) and randomized daily for 6 d. Analysis of data showed that column, day, treatment, and day by treatment interaction were significant sources of variation (P<0.01). Males or females feeding on ripe peach attracted significantly higher numbers of male and female beetles than all other treatments (Waller-Duncank-ratiottest,k= 100,P<0.05).

ISSN:1754-5692    

DOI:10.1093/ee/17.2.147

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

The water strider,Gerris paludum insularis(Motschulsky), was reared in a growth cabinet at seven constant temperatures from 10 to 40°C under a 16:8 (L:D) photoperiod. There were highly significant differences among development times for all temperature regimes and the immature stages. Eggs failed to hatch at 10 and 40°C. The lower developmental temperature threshold was estimated to be 11.0°C and the upper, 35.6°C. Total development required 500 Celsius degree-days (DD) above threshold. The optimal temperatures for development and survival were 25 and 30°C, respectively. The presence or absence of this species in its normal range of distribution and habitats may be a useful indicator of thermal pollution.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.150

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Developmental rates of individual stages of California red scale,Aonidiella aurantii(Mask.) andAphytis melinusDeBach were determined at 17, 20, 25, 26.7, 30, and 33°C. A linear degree-day model estimated the scale's developmental time in the field more closely (4–7% of observed) than did either the polynomial (16–19%) or thermodynamic models (17–21%). The model overestimated male duration by 20%. Although actual duration of California red scale stages that are susceptible to parasitism byA. melinusdecreased with increasing temperature, their durations relative to other stages increased. The size of non-growing stages (second molt and prepupa) decreased with increasing temperature. High temperatures also reduced the size of growing stages (second and third instars) and therefore affected the period during which scales were vulnerable toA. melinus. High temperatures also reduced the proportion of the scale population available toA. melinusfor female progeny production. When developing scales were exposed to variable temperatures, average temperature during the developmental period predicted the size of second molt and prepupal stages. Based on developmental time,A. melinushas several generations to everyone of its host, thus its effectiveness as a biocontrol agent depends on a continuous supply of suitable scale stages to serve as hosts, especially for daughters.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.154

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Different color morphs of adultEarias insulana(Boisduval) could be induced under controlled environmental conditions in the laboratory. Maintenance of laboratory-reared larvae from hatching to pupation, under conditions of 17°C during 14–16 h of dark, and of 21–33°C during 8–10 h of light daily, produced high percentages of grayish brown adults. This process of induction continued through most of the larval stage. Elevating night temperatures above 21°C or day temperatures above 33°C reversed forms of the grayish brown to the typical form of greenish blue moths. Decreasing the light phase to 8 h or less inhibited the induction of the grayish brown color morphs.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.162

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Larval and pupal development of western corn rootworm was studied at eight constant temperatures ranging from 15 to 33°C. Development from hatch to adult stage occurred at 15–31.5°C; no larvae completed the second stage at 33°C. Adult survival decreased and wing deformities increased significantly at 15 and 31.5°C. Optimum development and survival occurred within the temperature range of 21–30°C. Males developed faster than females in all stages at temperatures from 18–30°C, but the sexes have a similar lower thermal threshold of development estimated to be near 9°C. The relationship between developmental rate and temperature was described for both sexes in all stages using linear and nonlinear equations. The information presented will facilitate the development of phenological models for this important pest species.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.166

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Tissue phospholipids ofCulex tarsalisCoquillett collected as adults or pupae from breeding waters located in Kern County, southern California, contained an essential nutrient, the fatty acid eicosapentaenoic acid, in proportions that were three times as high as for routine laboratory-reared adults. Proportions of triacylglycerol eicosapentaenoic acid, although always much lower than for the corresponding phospholipid fractions, were also much higher for wild than for laboratory-reared mosquitoes. Another essential fatty acid, arachidonic acid, was present in phospholipids in similar proportions for wild and laboratory-reared mosquitoes, although levels of triacylglycerol arachidonic acid were usually higher in wild than in laboratory-reared material. These mosquito-essential fatty acids were detected as substantial proportions of the total lipid fatty acids of sludge and detritus from the bottom of fourC. tarsalisbreeding waters, and both fatty acids were major components of the lipids of three types of microcrustaceans that characteristically abound in the mosquito-breeding waters. The ecological significance of these findings is discussed, and their possible bearing on the sexual noncompetitiveness of laboratory-reared adults is noted.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.172

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Aspects of the development and mortality ofIps avulsus(Eichhoff) were studied at seven constant temperatures from 10 to 35°C. On average, eggs occupied 10.3% of the total time in the host, larvae 34.8%, pupae 11.8%, and teneral adults 43.1%. Plots of development rates (reciprocal of median times) and percent mortalities versus constant temperatures indicated that the insect is well adapted to high temperatures but sensitive to low temperatures. The timing of oviposition relative to sibling oviposition time in a slab had little effect on the development times of any life stage or the life cycle. Oviposition time influenced life-stage and life-cycle mortality, although the effects were not great. For example, the probability of larval death increased from 16.6 to 28.7% for individuals originating in the first and fourth quarters of the oviposition period. The probability of death due to cannibalism was less than 10% and was not influenced by oviposition time. No difference was observed in the overall proportion of males to total emerging beetles (0.496) and 0.5; however, this proportion increased with time throughout the emergence period. Models were developed to predict life-stage and life-cycle development times as functions of temperature. A mechanistic model described the development rate versus constant temperature relationship, whereas a cumulative Weibull function described the temperature-independent distributions of normalized development times. The life-cycle model was validated using a multiple-cohort simulation procedure and data ofI. avulsusemergence from three trees in each of three field plots. The validation indicated model suitability in a larger model of population dynamics, although additional testing is indicated.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.181

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Reemergence of adultIps avulsus(Eichhoff) from bark slabs was studied at seven constant temperatures from 10 to 35°C. Reemergence occurred at 15–35°C, with more than 95% of all beetles reemerging in the 25–35°C range. Reemergence declined to 68% at 15°C. The relationship of adult residence time to temperature formed a backward J-shaped curve, with the longest residence time occurring at 15°C (84.4 d) and the shortest time at 32°C (8.2 d). Generally, differences in the residence times between sexes were small, and no consistent pattern of one sex reemerging before the other was observed across temperatures. A two-component model consisting of a reemergence rate versus temperature function and a cumulative Weibull distribution of normalized residence times predicted percent reemergence of a population over time. Good results were obtained when model predictions were compared to reemergence from three trees in each of three field plots. These validations indicate suitability of the reemergence model for use in a larger model of population dynamics.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.192

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

Relationship between leaf detritus and productivity ofAedes triseriatus(Say) from beech treeholes was studied. Leaf mass in treeholes was positively correlated with area of treehole entrance. Leaf packs in treeholes lost ca. 69% of their mass during the summer season. In the first experiment lasting 18 wk, there was no difference in number of mosquitoes emerged, average individual mass, development time, or total mass of males or females from treeholes without leaves or treeholes with leaves. Individual mosquitoes were not generally smaller in size with increasing date of emergence. Inorganic nutrient (nitrite, nitrate, phosphate, sulfate, and ammonia) and dissolved organic carbon concentrations in treehole water varied seasonally with rainfall and other factors but did not differ between groups of treeholes with or without leaves. Bacterial concentrations in treehole water were higher in nine treeholes before than after a rainfall, ranging overall from 1.92 × 106to 54.70 × 106cells per ml. In a second experiment lasting about seven weeks, there was no difference in larval mass between treeholes with leaves and those without leaves. Behavioral observations showed that larvae filtered treehole water and browsed tree bark and leaves. Overall, our results suggest that leaves are probably only one of many food resources for mosquito larvae in treeholes; bacteria in treehole water may be more important as food than microbiota attached to leaves.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.199

出版商:Oxford University Press    

年代:1988

数据来源: OUP

摘要:

The effect of acute ozone exposure of eastern cottonwood (Populus deltoidesBartr.) on the survivorship, reproduction, and development of the aphidChaitophorus populicolaThomas (Homoptera: Aphididae) was investigated. Cottonwoods were exposed to 397μg/m3(0.20 ppm) ozone or charcoal-filtered air and infested with aphids on leaf plastochron index 5, 40 h after fumigation. Aphid performance was not significantly different on plants exposed to ozone compared with charcoal-filtered air-treated control plants. These data do not support the notion that aphid performance will directly increase on air pollution-stressed plants. We also examined settling and feeding preference of aphids for cottonwood leaves of different developmental ages. Aphids significantly preferred leaf plastochron index 5 to all other leaf ages. These data support hypotheses relating aphid leaf preference to stages of leaf development. Reproduction of the cottonwood leaf rust fungus (Melampsora medusaeThum.) and the imported willow leaf beetle (Plagiodera versicoloraLaicharting) are reduced on ozone-fumigated plants (reported elsewhere). If aphid populations are affected by competition with these cottonwood pests for leaf resources, then aphid pest potential may actually increase in areas characterized by episodic ozone concentrations because of ozone-induced decreases in populations ofM. medusaeandP. versicolora.

ISSN:1754-5692    

DOI:10.1093/ee/17.2.207

出版商:Oxford University Press    

年代:1988

数据来源: OUP