摘要:

Stable flies,Stomoxys calcitrans(L.), were offered one, two, or ad libitum meals of citrated bovine blood on a daily basis in combination with nectar (a 1:3 dilution of wild honey in water) at levels of none, one, or ad libitum each day. Reproduction during a 12-d period was depressed with ad libitum nectar to as low as 35% of flies receiving nectar once per day or not at all. Direct interference with blood hunger appeared to occur in nectar-fed stable flies. Female survivorship decreased 21–29% among flies receiving ad libitum nectar. Flies given blood ad libitum produced>55 and 40% more eggs than flies offered blood once or twice per day. In a separate experiment, the survivorship of adult flies given dilutions of purified sugars was measured. Statistically, the highest mean survival time was 8 d for flies fed trehalose, 5 times the length allowed by water alone. Fructose and melezitose were next, with life spans that were ≍4 times that of water-fed flies. Maltose, raffinose, glucose, sucrose, and melibiose meals extended life spans from 3 to 2 times that of water. The disturbance to reproduction that results from nectarophagous activities is discussed in view of the normal field activities of the species.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.141

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Queens ofDolichovespula maculata(L.) were collected before the hibernation period in the fall, before and shortly after nest initiation in the spring, and after colonies had produced more than two worker broods. Fresh and dry weights were determined for all queens, and a seasonal comparison of the energy reserves of lipids, sugar, and glycogen was performed on the thoracic and abdominal tagmata. Total nitrogen also was quantified to estimate protein changes by season. The results show that during hibernation, 70.1% (101.8 mg) of the lipid reserves, 79.4% (26.0 mg) of the sugar reserves, and 84.8% (6.9 mg) of the glycogen reserves were used. Furthermore, lipid use accounted for 35% of the dry-weight loss, sugar use 12%, and glycogen use 6%. Total thoracic nitrogen remained constant throughout the year, whereas abdominal nitrogen was the same in the fall and spring queens but increased in the summer queens. The results of this study suggest that most queens that survive the winter and successfully initiate nests have similar quantities of energy reserves. The implications of solitary foraging behavior are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.148

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Natural and synthetic food odors presented alone and in combination with aggregation pheromone were investigated forCarpophilus lugubrisMurray in the field. Whole-wheat bread dough and a synthetic bread dough odor were comparable for attractingC. lugubris,a result that paralleled our previous findings in the wind tunnel. The aggregation pheromone alone elicited little beetle response. However, the addition of aggregation pheromone to bread dough or to the synthetic bread dough odor significantly increased beetle attraction to a level 4.8- and 3.1-fold greater, respectively. The seven components in the synthetic bread dough odor were clustered into three groups based on their activities in attractingC. lugubris,and beetle catch was reduced by the elimination of any group. Beetle catch with a three-component blend of acetaldehyde, ethyl acetate, and 2-methylpropanol was also significantly less than that with the seven-component blend. Addition of the aggregation pheromone synergistically increased beetle attraction to synthetic food odor blends by 2.6 to 3.5 times. Synergism did not significantly vary among synthetic food odor blends. This study confirms the chemical identity of food volatiles modulating food finding inC. lugubris,and demonstrates that the wind-tunnel bioassay can act as a good predictor of chemically mediated host finding in the field.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.156

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Concentrations of cadmium, copper, and zinc were determined in adults, larvae, larval faeces, and host plants of four monophagous and one oligophagous phytophagous insect species. In this way, transport of these metals from the plants via the larvae to the adults could be followed. The influence of metamorphosis on heavy metal concentrations was also studied. In general, metal concentrations tended to be lowest in plants, intermediate in larvae, and highest in adult insects. The exception was cadmium, concentrations of which were higher in larvae than in adult insects. Concentrations of cadmium were higher in faeces than in food plants, whereas no such difference was found for copper and zinc.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.160

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

The development, flight activity, and density of the native eulophid,Sympiesis marylandensisGirault, a major parasitoid ofPhyllonorycterspp., were examined in apple orchards, forests or both at two Connecticut sites between 1985 and 1988. In orchards, S.marylandensishad two or three generations per generation ofP. crataegella(Clemens), for a total of six or seven per year. The proportion of parasitoid pupae in diapause steadily increased from September to November. Males numerically dominated the pupal samples. In apple orchards, adults ofP. crataegellacaptured on yellow sticky traps had three major periods of activity, whereasS. marylandensishad three or four that corresponded to periods of adult parasitoid emergence. The trap catch ofS. marylandensisin June to early July was relatively low in a commercial orchard, but not in an unsprayed orchard. Autumn activity was the greatest in years when an insecticide for leafminers was not applied. Parasitoid abundance on traps was lower in forests than in orchards, and higher in spring and autumn than at other times in forests. From September to November of 1988, the density ofP. crataegellaimmatures in a sprayed orchard was negatively correlated with the density ofS. marylandensis. The effect ofS. marylandensisis greater than was suggested previously.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.164

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

The effects of short-term phenological changes in different tree species on development and survival of the gypsy moth parasitoidCotesia melanoscela(Ratz.) are examined. Larvae stung byC. melanoscelaand an unstung control group were allowed to develop on foliage from four tree species (red maple, mockernut hickory, American beech, and white oak) started on five different dates during a 16-d period after bud break. Survival ofCotesialarvae declined Significantly with start date on all four species; however, white oak supported high wasp survival for most of the period. Wasp development time also increased significantly with increasing start date on each species. Stung larvae suffered significantly higher mortality from causes other than wasp emergence than did control larvae. The implications for underestimating mortality attributable to parasite attack are discussed. In particular,C. melanoscelaprobably causes significantly greater mortality of gypsy moth larvae than estimated from parasite emergence.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.173

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Nosema pyrausta(Paillot) detrimentally affected the development of its host,Ostrinia nubilalis(Hübner). Larvae exposed to the microsporidium during the first two stadia formed abnormal pupae or emerged as abnormal adults. Infections of later instars reduced average longevity of resultant adult females by at least 2 d and fecundity by at least 50%. Eggs from infected adults were contaminated with the microsporidium. The prevalence of transovarial-transovum infections, determined by the presence of spores in eggs or in emerging larvae, varied with the spore concentrations to which the parent females were exposed and with the time (within the oviposition period) that the eggs were laid. Per os infection ofO. nubilalislarvae withN. pyraustais important in maintaining this microsporidium in a population ofO. nubilalisas well as reducing the vitality of the population.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.178

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Effects of rice field water quality and host age on the infectivity ofLagenidium giganteumCouch toCulex tarsalisCoquillett were investigated in the laboratory for 3 yr. Selected water chemistry parameters were quantified to determine their influence on the corresponding infection rates. Large variation in dose-response was obtained among different water samples. When individual instars were exposed to a concentration of 10 zoospores/ml in different water samples, infection for the first through fourth instars respectively averaged 49, 42, 56, and 47%, with 78% of the variation in larval mortality significantly correlating with changes in common water chemistry parameters. Singly, none of the water chemistry variables accounted for>35% of the variation in infection rates. The causal relationships between changes in water chemistry and infectivity were unclear. When all instars were bioassayed in the same container to remove variation caused by different water samples, the first three instars were equally susceptible to infection, and the fourth instar was less susceptible. With exposure to 100 zoospores per ml, the period of lethal infection increased from 18 to 48 h as host age increased from the first to the fourth stadium.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.183

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Two nabid species,Nabis roseipennisReuter andN. americoferus(Carayon), were collected from alfalfa fields in Indiana in 1988 and 1989. Body weights and numbers of eggs at dissection were recorded and compared within and between species by location and time. The numbers of eggs at dissection were regressed on body weight, and compared between species. Overall,N. roseipenniswere found to weigh more thanN. americoferus. N. americoferusappeared to have a minimum weight threshold for egg production. No such threshold was evident forN. roseipennis. Egg-to-weight relationships suggested thatN. americoferuswas more efficient at producing eggs thanN. roseipennis,which helped to explain interspecific comparisons of fecundity. The findings of the study are compared to similar studies of nabid reproduction and related to the potential use of nabids in pest management.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.191

出版商:Oxford University Press    

年代:1992

数据来源: OUP

摘要:

Development of the convergent lady beetle,Hippodamia convergensGuérin-Méneville, was compared at six constant temperatures. Two populations, one from Corvallis, Oreg., and another from Tucson, Ariz., did not differ in larval survival or developmental rates. Mortality from eclosion of the first instar to adult emergence was 100, 83, 15, 18, 10, and 5% at 13, 17, 21, 25, 29, and 33°C, respectively. Development from oviposition to adult ranged from 51.9 d at 17°C to 11.4 d at 33°C. The heat-unit requirements for development from egg to adult were 228 degree-days above a developmental threshold of 12.5°C. Published data on development ofH. convergensfrom Ithaca, N.Y., and Bushland, Tex., suggest a constancy in developmental requirements for the species from four widely separated regions of North America.

ISSN:0046-225X    

DOI:10.1093/ee/21.1.197

出版商:Oxford University Press    

年代:1992

数据来源: OUP