摘要:

Midlatitude survival ofAnticarsia gemmatalisHübner, the velvetbean caterpillar, is related to cooling degree-days (°C-days<10.9°C). Model construction required a cooling degree-day algorithm and spatial distributional-data of velvetbean caterpillar populations in Florida from November to March (inclusive). Model input required lower and upper developmental thresholds of the velvetbean caterpillar and site-specific minimum and maximum daily temperatures. Model output was cooling degree-days per 24 h per site. Total cooling degree-days at each site were used to delineate the midlatitude survival boundary for velvetbean caterpillar. The model was validated quantitatively. Extended calculations with the model delineated a midlatitude survival boundary in south Texas slightly south of Mission and Harlingen. Field-collected velvetbean caterpillar in Texas and Mexico validated the model's calculations.

DOI:10.1093/ee/19.4.1017

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The relationship between mean wing length and density of gypsy moth,Lymantria dispar(L.), is described for leading-edge populations in Virginia and Maryland. Mean number of moths per trap, egg mass density, and eggs per mass in the succeeding generation were all related to mean male moth wing length using regression and correlation analyses. Because of the variability in egg mass density, predictions derived from regression models should be viewed as a part of a sequential approach to quantifying gypsy moth populations in management programs. Wing length estimates can assist in establishing priorities for egg mass surveys in a pheromone trap-based monitoring system. The use of wing lengths together with other density measures of gypsy moth populations can provide managers with additional information and put into use a measure of population quality for gypsy moth management decisions.

DOI:10.1093/ee/19.4.1024

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The spatial distribution of larvalIxodes damminiSpielman, Clifford, Piesman,&Corwin was examined at two sites in Westchester County, N.Y., an area endemic for Lyme disease. Larval abundance peaked in early August and was marked by a highly clumped distribution reflecting high concentrations of newly hatched larvae. Subsequent sampling indicated an increasingly uniform distribution of larvae as measured by the variance/mean ratio and Lloyd's index of patchiness. An experiment using ticks marked with fluorescent powder to illustrate the degree of active dispersal (tick disperses by its own movement) indicated little lateral movement; only 3 (4%) of the 77 marked larvae recovered during the experiment were found beyond 3 m from the release point. The recovery of unfed larvae (12 larvae [0.6% of total] were recovered from raccoons,Procyon lotor(L.); 9 [3.4%] from mice,Peromyscus leucopusRafinesque; and 32 [9.0%] from opossums,Didelphis virginiana(Kerr)) from captive hosts in the laboratory suggests that passive transport of unfed larvae may be a mechanism of dispersal.

DOI:10.1093/ee/19.4.1029

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

A field study was conducted in Tucson, Ariz., in 1987 to evaluate the dispersal of cotton (Gossypiumspp.) pollen grains by honey bees,Apis melliferaL., in relation to distance from pollen source and time-of-day. The experimental field consisted of 10 rows with rows 1 and 2 planted to both male-fertile upland cotton (G. hirsutumL.) (south end) and male-fertile Pima cotton (G. barbadenseL.) (north end). Rows 3 to 10 were planted with an upland cytoplasmic male-sterile line. The hourly pattern of pollen deposition on the stigmas of male-sterile lines was determined from 0800 to 1600 hours (MDST). The highest number of upland or Pima pollen grains deposited on the stigmas of male-sterile lines was from the rows nearest to the pollinator rows. The peak time of pollen deposition on the stigmas was between 1000 and 1200 hours. These data indicate that the distance across which bees transfer pollen is a factor in choosing the optimum combination of male-fertile and male-sterile lines, and a reduction of pollen loads on stigmas during the afternoon hours may result from accidental pollen removal by honey bees.

DOI:10.1093/ee/19.4.1034

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The seasonal distributions and biology of four species of billbug on New Jersey turfs during 1986 and 1987 were examined;Sphenophorus parvulusGyllenhal, a common pest of turfgrass, and three additional species,S. venatuss.l. (Say),S. minimusHart, andS. inaequalis(Say), that had previously been overlooked as pests of cool-season turfgrasses in New Jersey. Linear pitfall trap collections of adults indicated: (1) a nearly equal overall abundance of the four species, (2) greater activity ofS. inaequalisin the early spring and autumn, and (3) continued activity ofS. venatusthrough the summer. The abundance ofS. venatusadults throughout the summer, and continuous egg laying of all four species through August suggested a partial second generation. Larvae of all four species were found damaging cool-season turfgrasses during July. Laboratory-rearing work found little difference in the number of days for egg hatching and pupation, but a longer larval period forS. venatus. To facilitate identification and study by turfgrass specialists, an illustrated key to eight known billbug turf pests is provided and their geographic distributions in the United States are reviewed.

DOI:10.1093/ee/19.4.1037

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The foraging territory size ofHeterotermes aureus(Snyder) was investigated on the Santa Rita Experimental Range south of Tucson, Ariz. A comparison of three techniques for delineating territorial boundaries suggested that the release and recapture of dyed termites and agonistic behavior among termites were the most reliable techniques, whereas spatial and temporal patterns of termite attack on baits were unreliable for determining boundaries. Data obtained with the first two techniques indicated that many territories encompassed an area of several hundred to a few thousand square meters. These data contrasted sharply with those obtained from spatial and temporal patterns of termite attack, which provided an estimate of 13.9 m2for average territory size.

DOI:10.1093/ee/19.4.1047

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

The seasonal occurrence and development of field populations ofManduca quinquemaculata(L.) andManduca sexta(Haworth) were monitored at the Kellogg Biological Station in Barry County, Mich., from late June to early September during 1985 and 1986. Results indicated that initial and peak oviposition were variable between years for both species and were not predictable by accumulated degree-days (DD), base 10°C. In both years, initial egg deposition occurred slightly earlier forM. quinquemaculatathan forM. sexta(DD 615 versus DD 728 in 1985 and DD 700 versus DD 742 in 1986), whereas peak oviposition was dependent upon the year in question. In 1985, oviposition forM. quinquemaculatapeaked approximately 100 DD earlier than forM. sexta. In 1986, the reverse was observed. Larval development occurred at the same rate in both species and was closely associated with degree-day accumulation requiring, on the average, 39 DD per stadium. Monitoring data from both years indicated thatM. quinquemaculatais likely univoltine in Michigan whereasM. sextais probably bivoltine.

DOI:10.1093/ee/19.4.1055

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Newly hatched fall armyworm,Spodoptera frugiperda(J. E. Smith), larvae were placed on the under surface of main stem leaves of cotton,Gossypium hirsutumL., emerging at main stem nodes 5, 10, and 15 in greenhouse and field cage studies to determine feeding sites, intraplant distribution, interplant movement, and survival of larvae throughout larval development. Feeding sites and survival of larvae in greenhouse and field cages were similar. First and second instars fed predominantly on leaves. Third instars fed equally on leaves and fruiting structures. Significantly more fourth, fifth, and sixth instars were found feeding on fruiting structures (squares, blooms, or bolls) than on leaves. Release site did not significantly (P74%) first, second, and third instars were found on structures emerging directly from the main stem or nodes 1 to 4 on branches located between main stem nodes 1 and 15. Later instars (fifth and sixth) were observed on middle to terminal portions of the plant, including branch tips. In the interplant movement study, larvae remained predominantly within average distances of 1 to 2.4 plants from the infested plant. No larva moved more than five plants from the site of release.

DOI:10.1093/ee/19.4.1060

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Larval habitats and adult emergence sites of the dominant ceratopogonid species were identified from a 14.6-ha site on Sea Island, a coastal Georgia barrier island, during a 14-mo period.Culicoideslarvae (5,717) were identified from salt marsh soil samples and were compared on the basis of vegetation, elevation, pH, and soil minerals.Culicotdes furens(Poey) larvae were significant for vegetation and calcium ion content and were most abundant in areas ofSpartina alternifiora(1.2 m) at elevations near the mean low-tide mark. Numbers of larvalC. hollensiswere significantly related to vegetation and presence of potassium ions.C. melleus(Coquillett) larvae were significant for soil pH and were found in areas ofDistichlis spicataat elevations near the high-tide level. All species occurred in acidic soils (mean pH 5.6). Other ceratopogonids encountered wereDasyhelea atlantisWirth and Williams,D. mutabilis(Coquillett) andLeptoconops linleyiWirth and Atchley;L. ltnleyiwas found for the first time in Georgia. The relative seasonal abundance of the instars was compared with adult abundance. Lower larval densities ofC. hollensisandC. melleusduring spring and fall coincided with periods of adult abundance. Higher larval densities during winter and summer correlated with the bimodal spring-fall seasonal abundances of adultC. hollensisandC. melleus.

DOI:10.1093/ee/19.4.1068

出版商:Oxford University Press    

年代:1990

数据来源: OUP

摘要:

Ovipositional preference of the Mediterranean fruit fly,Ceratitis capitataWiedemann, was examined using artificial hosts. Females laid significantly more eggs in larger hosts, spherical hosts, green and blue hosts, and they avoided hosts with papaya extract. Patterns of oviposition in tests with pairwise combinations of different host attributes showed that these preferences are integrated hierarchically. The preferred host shape was chosen over the preferred color, and host color was selected over fruit extract. Host size was the most important characteristic involved in eliciting oviposition by medflies.

DOI:10.1093/ee/19.4.1075

出版商:Oxford University Press    

年代:1990

数据来源: OUP