摘要:

The abundance of predatory and scavenger arthropod fauna in three age classes of accumulating bovine excrement was recorded in a 13-month study in southern Uganda (0° 25' N. lat.). These fauna consisted of 16 families of Coleoptera, 3 of Hemiptera, and 1 each of Dermaptera, Hymenoptera, Acarina, and Pseudoscorpiones. The Hydrophilidae and Staphylinidae comprised 60.8% of collected individuals, whereas 18.2% were Scarabaeidae, 6.3% were Scydmaenidae, and 5.7% were Histeridae. At least 94 species were found, the majority of which probably are endemic to east Africa. The greatest predator and scavenger biomass inhabited 1- to 8-day-old excrement, which also possessed eggs and larvae of the fliesMusca domesticaL. andStomoxys calcitrans(L.).

ISSN:0046-225X    

DOI:10.1093/ee/10.5.620

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Brood ball size and weight, manure burial rate, and offspring size ofOnthophagus gazella(F.) were demonstrated to increase as the size of the parent beetles increased. Adult size, in turn, reflected the quantity of provisions in the brood ball in which a beetle developed, regardless of the size of its parents. Also, under present experimental conditions, the sizes of the offspring from extremely large and small parents differed significantly from parental sizes, indicating a trend toward a medium size. The role of beetle size in dung ecology is discussed.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.626

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Insects were monitored in soybean of early-, medium-, and late-maturity groups planted April through July in several row spacings at four locations in Mississippi for 1 to 3 years. Nondamaging populations of the green c1overworm,Plathypena scabra(F.), were present from June through September, and damaging populations were observed at one location after a drought. Green cloverworm populations were generally higher in late plantings, in late-maturing cultivars, and in narrow-row plantings. Damaging populations of the velvetbean caterpillar,Anticarsia gemmatalisHubner, occurred in August or September. In 1976 and 1978 only the June and July plantings were seriously defoliated, but in 1977 all but the early-maturing April and May plantings were seriously defoliated. Velvetbean caterpillar populations were highest in late plantings, late-maturing cultivars, and in narrow-row plantings. Populations of loopers,Pseudoplusia includens(Walker) andTrichoplusia ni(Hubner), were generally less than 1/m2, but populations up to 3.2/m2occurred at one location after insecticide treatment. Effects of planting date, cultivar, and row spacing were not consistent. Populations of the Heliothis complex larvae were generally less than 0.05/m2, but populations as high as 3.74/m2were observed in blooming soybean. Populations of theHeliothislarvae were about equal in narrow- and wide-row plantings. In wide-row plantings, populations ofHeliothislarvae averaged 0.98/m2in closed canopy and 0.24/m2in open canopy soybean.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.631

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Data on adults reared in the laboratory from eggs and larvae collected from cotton fields indicated that changes in seasonal species composition inHeliothisoccurred during the period from 1963 to 1979 in the delta of Mississippi. In the mid-60s, the population was predominantlyH. zea(Boddie). In 1969, it changed to a predominantlyH. virescens(F.) population and continued essentially as anH. virescenspopulation through the 70s. In 1979, the population changed again to become a predominantlyH. zeapopulation. Adults reared from both eggs and larvae followed this pattern. The data also indicated that in most years a higher percentage of the adults reared from eggs than from larvae wereH. virescens.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.642

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Populations of the apple blotch leafminer,Phyllonorycter crataegella(Clemens), were sampled in two commercial apple orchards in Connecticut during 1978 and 1979. Each population developed three generations per year. Pupae of the third generation overwintered in fallen apple leaves, and adults emerged in late April and early May. In 1978, moth abundance increased sharply from the second to third flight period even though endosulfan, methomyl, or both were applied in the spring. In 1979, abundance of immatures and adults also increased markedly at the end of the growing season. Rise in population size was accompanied by an increase in the amount of larval food and a decrease in percent parasitism. Tissue feeders destroyed 38.9 and 52.3% of the photosynthetic area of attached and fallen leaves, respectively, collected in a severely infested orchard in October 1979. Impact of parasitism and other factors on populations is discussed.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.645

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Relationships between leafhopper feeding and the resulting effects on forage grasses have not been well defined. Therefore, the morphological and physiological responses of Kentucky-31 tall fescue to various population densities ofForcipata locawere examined in a 2-year field cage experiment. The detrimental effect ofF. locaon tall fescue was reflected primarily in reduced forage quality rather than in yield reduction. Significantly higher neutral detergent fiber concentrations, significantly lower water-soluble carbohydrate concentrations, and significantly lower in vitro digestible dry-matter concentrations were observed. Increased fiber and decreased cell content reduced forage digestibility.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.650

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Egg and 1st-instar survival as a function of soil texture and moisture was estimated under laboratory conditions. These stages were found to be resistant to extreme moisture conditions in various types of soils. Delays in egg development were observed particularly in saturated soils. These results are used in developing a mathematical model of survival of the early instars under variable moisture conditions, and simulations are compared with field data. Field survival was highly variable and correlated only partially to model outputs. Probable causes of the discrepancies are discussed.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.654

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Japanese beetle grubs of the three larval instars were reared at varying densities, and their survival rates were compared. Although, 1st-instar grubs survived better at higher densities, 2nd and 3rd instars had lower survival in crowded conditions. An analysis of the weight of grubs reared at various densities suggests that competition occurred which caused higher mortality among smaller individuals.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.661

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

Evidence of relatively high-fecundity populations of the gypsy moth,Lymantria dispar(L.), was found along both the advancing front of the generally infested area and in an area where population build-up and collapse have been common.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.663

出版商:Oxford University Press    

年代:1981

数据来源: OUP

摘要:

A study was conducted to quantify various types of damage caused by the pecan weevil in a pest-managed, commercial pecan orchard. The types of damage evaluated included premature nut drop, black spots on the kernel, shriveled kernels, and destruction of the kernel by larvae. Premature nut drop due to adult weevil feeding was the most prevalent type of weevil-induced damage observed in the study. Although the primary objective of the study was to quantify pecan weevil damage, it was observed throughout the study that the greatest percentage of nut loss occurred from nuts dropping prematurely for unknown reasons.

ISSN:0046-225X    

DOI:10.1093/ee/10.5.668

出版商:Oxford University Press    

年代:1981

数据来源: OUP