Seasonal Phenology and Developmental Biology of Amorbus obscuricornis (Westwood) and Gelonus tasmanicus (Le Guillou)(Hemiptera : Coreidae)

1997 ◽  
Vol 45 (1) ◽  
pp. 49 ◽  
Author(s):  
M. J. Steinbauer

Detailed studies of the seasonal phenology and developmental biology of two eucalypt-feeding coreid species,Amorbus obscuricornis and Gelonus tasmanicus, were undertaken over three years in Tasmania. Both species are univoltine, their active season being from spring to autumn, with the adults being the overwintering stage. Adults of A. obscuricornis andG. tasmanicus emerge during spring to feed, mate and oviposit. Periods of peak copulatory activity and gravidity of females in both species correspond to times when the proportion of males to females is slightly male biased. Eggs of A. obscuricornis did not hatch at temperatures below 15˚C while the number of eggs of G. tasmanicus hatching at 13˚C remained high. The minimum developmental threshold temperature and number of degree-days (DD) required for hatching by eggs of A. obscuricornis and G. tasmanicus were estimated to be 11·8 and 10·8˚C and 147 and 136 DD, respectively. Embryonic developmental rates are considered to reflect differences in the evolved temperature preferences of each species. During spring and summer the nymphs develop through five instars to eclose in autumn just before overwintering. Second-instar mortality for both species was high, suggesting that the initiation of feeding may be a crucial developmental stage.

1991 ◽  
Vol 123 (6) ◽  
pp. 1183-1197 ◽  
Author(s):  
A.W. Schaafsma ◽  
G.H. Whitfield ◽  
C.R. Ellis

AbstractDevelopmental rates of post-diapause eggs of Diabrotica virgifera virgifera LeConte were compared in the laboratory at six constant temperatures, 12, 16, 20, 24, 28, and 32°C. Linear and nonlinear models were fitted to temperature versus developmental data and were used to predict egg hatch in the field. A four-parameter model fitted to median developmental rates (r2 = 0.99) indicated that development was linear between 16 and 28°C, optimal at 28°C, and decreased at 32°C. The lower development threshold (± SE) (10.5 ± 0.1°C) was determined by linear regression and the x-intercept method. Completion of post-diapause egg development required 258 ± 3 degree-days (± SE) above the base temperature. This compared well with the mean degree-days accumulated to 50% hatch (± SE) of 265 ± 24 which we observed in the field at several locations over 3 years using a degree-day model incorporating an 11°C developmental threshold and soil temperatures at 5- and 10-cm depths. A stochastic simulation model, incorporating a nonlinear developmental function dependant on soil temperatures taken every 2 h also predicted 50% hatch within 2 days. This model was validated in the field with 19 independent records of soil temperatures for several locations at two depths in the soil over 3 years. The simulation model accurately predicted time of 5 and 95% hatch, which indicates that this model has broad application in predicting the pattern of egg hatch for pest management.


Biologia ◽  
2010 ◽  
Vol 65 (5) ◽  
Author(s):  
Radovan Malina ◽  
Ján Praslička ◽  
Janka Schlarmannová

AbstractDevelopmental rates of the aphid Aphis pomi and its parasitoid Aphidius ervi were compared at four constant temperatures (15, 20, 25, 30°C). Aphis pomi required 159.07 degree-days (DD) above lover developmental threshold (LDT) of 0.3°C. Aphidius ervi required 229.73 DD above LDT of 5.98°C. Developmental rate of A. pomi is higher than the developmental rate of A. ervi at the same conditions


1992 ◽  
Vol 124 (5) ◽  
pp. 935-941 ◽  
Author(s):  
Francisco Infante ◽  
Juan H. Luis ◽  
Juan F. Barrera ◽  
Jaime Gomez ◽  
Alfredo Castillo

AbstractThe relationship between temperature and rate of development is described for Cephalonomia stephanoderis Betrem, an imported ectoparasitoid of the coffee berry borer Hypothenemus hampei (Ferrari).For all stages, development rate increased linearly with temperature between 17 and 32°C. However, at 37°C both eggs and larvae died. When the parasitoid constructed a cocoon, the lower developmental threshold (t) varied from 11.8°C in the eggs to 14.2°C for pupae; when no cocoon was constructed, it varied from 11.8°C for the eggs to 14.3°C for pupae. The lower developmental threshold, from egg to adult, was 13.7°C (with cocoon) and 13.8°C (without cocoon). As these differences were small in relation to the standard errors of the estimates, they were not considered different. Because C. stephanoderis always constructs a cocoon under field conditions, the threshold temperature of 13.7°C seems to be the most suitable.Physiological time expressed in degree-days (DD) for the egg to adult cycle of C. stephanoderis is 252.7 ± 45.3 DD (α = 0.05) when a cocoon is constructed, and 242.5 ± 35.1 DD (α = 0.05) when pupation occurs without construction of a cocoon.


2000 ◽  
Vol 132 (6) ◽  
pp. 939-949 ◽  
Author(s):  
K.L. Ryall ◽  
S.M. Smith

AbstractBrood production and shoot feeding by the pine shoot beetle, Tomicus piniperda (L.), were studied over 3 years in naturally infested plantations of Scots pine, Pinus sylvestris L. (Pinaceae), near Guelph and Waterloo, Ontario, using trap-logs. Adult beetles produced a single brood in 1996 and 1997 and two broods in 1999. Galleries for the first brood were all initiated under the bark over a 2- to 3-week period from mid-April to early May. The lone second brood occurred in early June. In all years, eggs were present by late April, larvae by mid-May, pupae by late June, and new adults by mid-July. Complete development (egg–pupa) required 12–13 weeks for the first brood and 8 weeks for the second brood. First-brood adults emerged over a 2- to 3-week period from early to mid-July in all years, with second-brood adults emerging in late July. The effective heat sums (degree-days (°d) > developmental-threshold temperature) were 77–79 °d for eggs, 267–293 °d for the larval stage, 139–152 °d for the pupal stage, and 43.2 °d for the pre-emergence stage, depending on the developmental-threshold temperature used. The total heat sums for the first brood (1249.8 ± 73.3 °d > 0 °C) were larger that those required for the second brood (856.4 ± 124 °d > 0 °C). Overall, values for first-brood development were similar to those calculated for European and Asian populations. Pine shoots in the upper tree crowns were used by adult beetles for maturation feeding between late July and late September in both 1995 and 1996. The re-emerging parental adults fed upon 1-year-old shoots, whereas newly emerging adults fed primarily upon current-year shoots. The beetles appeared to move to overwintering sites in late October to November, and no adults were found overwintering in shoots on the trees or the ground. Our results parallel those obtained by others under similar climatic conditions in Europe, and can be used to improve the management and regulation of this species as it becomes established in our native pine forests.


Author(s):  
Yingchao Ji ◽  
Guohua Li ◽  
Chenggang Zhou ◽  
Shuyan Yin

Abstract Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.


2017 ◽  
Vol 48 (1) ◽  
Author(s):  
Taciana Melissa de Azevedo Kuhn ◽  
Alci Enimar Loeck ◽  
Marcos Botton

ABSTRACT: The thermal threshold and thermal requirements of Neopamera bilobata were determined, and the number of generations that this species may produce in the main strawberry-producing regions of Brazil was estimated. In a climate chamber (70±10% RH and 12h photophase) at 16, 19, 22, 25, 28, or 30±1°C, the development of 120 eggs was monitored until the adult stage, at each temperature. Nymphs were maintained in individual cages and fed on strawberry fruits of the cultivar Aromas. The mean duration and viability of the egg and nymph stages were calculated by estimating the lower and upper developmental thresholds and the thermal constant, and this information was used to estimate the number of generations per year in different strawberry-producing regions of Brazil. The egg-to-adult duration decreased as temperatures increased, up to 28°C (93.4, 83.2, 43.9, and 31.4 days at 19, 22, 25, and 28°C, respectively). Viability of nymphs was highest between 22 and 28°C. At 30°C, the egg-to-adult duration increased (36 days), while the viability decreased (11.11%). The lower egg-to-adult developmental threshold was 15.2°C and the thermal constant was 418.4 degree-days. Calculating the number of generations indicated that the largest number (5.1 generations yr-1) was obtained for the municipality of Jaboti, Paraná, and the smallest for Caxias do Sul, Rio Grande do Sul (1.9 generations yr-1). Our findings demonstrated that important strawberry-producing regions in Brazil are suitable for the development of N. bilobata.


2013 ◽  
Vol 49 (No. 2) ◽  
pp. 89-97
Author(s):  
T. Středa ◽  
O. Vahala ◽  
H. Středová

The sum of effective temperatures (SET) of adult western corn rootworm (WCR) occurrence was determined based on several criteria. The risk of WCR occurrence was mapped, and the areas of continuous reproduction of WCR in the Czech Republic were identified. The daily soil SET was observed until the initial adult WCR occurrence, and it ranged from 414 degree days (DD) when the lower threshold temperature (LTT) was 12.5°C at 0.02 m depth to 719 DD (LTT of 10°C at a depth of 0.05 m). The daily air SET ranged from 415 DD (LTT 12.5°C at a height of 2 m) to 726 DD (LTT of 10°C at a height of 0.05 m).  


2017 ◽  
Vol 108 (3) ◽  
pp. 400-405
Author(s):  
M. Su ◽  
X. Tan ◽  
Q. Yang ◽  
C. Zhao ◽  
F. Wan ◽  
...  

AbstractAphelinus mali(Haldeman) is an effective natural enemy of woolly apple aphid (WAA),Eriosoma lanigerum(Hausmann). Previous studies have found that, with WAA from Shandong Province (Qingdao) as the host, there are significant differences in various biological characteristics between a Shandong clade and Liaoning clade ofA. mali. The ability of the Shandong clade to control this aphid was significantly higher than that of the Liaoning clade in Shandong Province. In order to determine whether differences were caused by better adaptation of the Shandong parasitoid clade to the population of the host in that province or if it represents a more general fitness of this clade to control the host regardless of location, we compared the same parasitoid clades with hosts from Hebei Province. We found no significant differences in the developmental threshold temperature, effective accumulated temperature, fecundity, longevity, and oviposition period of the two clades, but the duration of host searching of the Shandong clade was significantly longer than that of the Liaoning clade. The instantaneous attack rate, the control ability (a/Th), the search parameter (Q) of the Shandong clade (0.0946, 0.543, 0.0725) ofA. maliwere higher than that of the Liaoning clade (0.0713, 0.382, 0.0381), and therefore, with WAA from Hebei Province as the host, the host adaptability of the Shandong clade ofA. maliwas not worse than that of the Liaoning clade, while the pest control ability of the Shandong clade was still greater than that of the Liaoning clade.


1996 ◽  
Vol 121 (2) ◽  
pp. 269-273 ◽  
Author(s):  
Diane E. Dunn ◽  
Janet C. Cole ◽  
Michael W. Smith

The objective of this study was to determine the most advantageous time to collect cuttings of Chinese pistache, a commonly recommended ornamental shade tree that is difficult to propagate by cuttings. In 1993, calendar date and degree days (daily mean temperature -7.2C) were used to estimate an appropriate cutting time. The greatest percentage of rooted cuttings occurred in male cuttings harvested on 13 May 1993 (397 degree days) and treated with 17,500 mg·liter-1 IBA or in male cuttings harvested on 20 May 1993 (482 degree days) and treated with either 8750 or 17,500 mg·liter-1 IBA. In 1994, cutting time was associated with calendar days, degree days, and morphology. The most rooted cuttings (44%) were from green softwood cuttings taken on 9 May 1994, which was 380 degree days from orange budbreak using a threshold temperature of 7.2C. Orange budbreak was characterized by separation of the outer bud scales such that the orange, pubescent inner bud scales were visible. Cuttings taken on 9 May 1994 and treated with 8750 mg·liter-1 IBA produced the most primary and secondary roots and the longest primary roots per cutting. Male Chinese pistache cuttings should be collected from green softwood or red semi-softwood stems when about 380 to 573 degree days have accumulated after orange budbreak. Chemical names used: indolebutyric acid (IBA).


2008 ◽  
Vol 61 ◽  
pp. 1-7 ◽  
Author(s):  
L. Peacock ◽  
S.P. Worner

In this study the biological and ecological traits of two groups of phytophagous insect pests were examined to determine attributes that may influence establishment in New Zealand Biological and ecological attributes of a group of insect species that is established in New Zealand were compared with species that are not currently established It was found that the species established in New Zealand had a significantly wider host plant range than species that have not established The lower developmental threshold temperature was on average 4C lower for established species compared with nonestablished species These data suggest that species that establish well in New Zealand have a wide host range and can tolerate lower temperatures compared with those that have not established


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