Developmental rates of the aphid Aphis pomi (Aphidoidea: Aphididae) and its parasitoid Aphidius ervi (Hymenoptera: Aphidiidae)

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

2008 ◽  
Vol 44 (No. 1) ◽  
pp. 19-24 ◽  
Author(s):  
R. Malina ◽  
J. Praslička

Temperature-dependent development, longevity and parasitism of the parasitoid Aphidius ervi Haliday was measured at four constant temperatures between 15°C and 30°C using Aphis pomi de Geer as host. The thresholds for egg-mummy and mummy-adult development were 6.8°C and 3.9°C, respectively. Development into mummies required an average of 146.3 degree-days (DD), while development into adults took an average of 85.3 DD. Longevity was increasing linearly in the range from 15°C to 25°C (8–15 days), but was lower at 30°C (11 days). The relationship between parasitism, recorded as percent aphids mummified, and temperature was increasing at the temperatures 15–25°C, but decreasing at higher temperatures; 10.8% of the aphids were parasitised at 15°C, 15.9% at 25°C and 14.6% at 30°C. These results are compared with previously reported data on temperature-dependent development of A. ervi on a different host.


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.


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.


1978 ◽  
Vol 110 (1) ◽  
pp. 57-62 ◽  
Author(s):  
R.G. Taylor ◽  
D. G. Harcourt

AbstractWhen the immature stages of Crioceris asparagi (L.) were reared at 10 constant temperatures, differential rates of survival and development were observed. The duration of all stages decreased with increase in temperature up to 32°C. The eggs tolerated a wider range of temperatures (8°–34°C) than larvae and pupae (10°–34°C). Developmental rates plotted against temperature did not deviate significantly from fitted curves of the form 1/y = K/1 + ea−bx. During three generations, accumulated degree-days above a base of 10° during development of C. asparagi in the field did not differ significantly from stage thermal requirements as calculated.


1974 ◽  
Vol 106 (1) ◽  
pp. 93-100 ◽  
Author(s):  
J. C. Guppy ◽  
M. K. Mukerji

AbstractWhen Hypera postica (Gyll.) was held at 11 constant temperatures, the hatching rate for eggs increased with rise in temperature from 8° to 20 °C and remained maximal to 32 °C. None hatched at 6 °C. Larvae survived at 10° to 35 °C with high mortality only at these limits. Pupae survived at all temperatures above 10 °C but at 35 °C half of the adults were deformed. Duration of all stages decreased with rise in temperature up to 32 °C. Developmental rates plotted against temperature did not deviate significantly from fitted curves of the form 1/y = K/(1 + ea−bx).The optimum temperature, based on maximal rates of development and survival, for eggs and young larvae was near 32 °C and for older larvae and pupae, 30 °C. Accumulated degree-days above a base of 10 °C during development of H. postica at two Ontario locations did not differ significantly from thermal requirements calculated.


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.


1997 ◽  
Vol 87 (5) ◽  
pp. 487-495 ◽  
Author(s):  
V. Jarošík ◽  
M. Koliáš ◽  
L. Lapchin ◽  
J. Rochat ◽  
A.F.G. Dixon

AbstractThe developmental rate of Frankliniella occidentalis (Pergande) was determined on cucumber Cucumis sativus cv. Sandra over a range of constant temperatures. The lower developmental threshold (LDT) and the sum of effective temperatures (SET) for the pre-imaginal development were 10.7°C and 231.1°C, respectively. The rate of population increase was assessed as the sum of effective temperatures above the lower developmental threshold by monitoring the numbers of thrips on individual leaves of cucumber under commercial greenhouse conditions. Population growth was characterized by an early stochastic phase, corresponding to pre-imaginal development of the first generation, and followed by an exponential phase starting with the second generation, the rate of which did not vary between plants. Throughout the exponential phase, the rate of population growth increased with time/age of plant. As significant damage to cucumber may occur during the exponential phase of population increase, the sum of effective temperatures of 231°C can be used to predict when damage is likely to start to occur.


Parasitology ◽  
1997 ◽  
Vol 114 (2) ◽  
pp. 123-134 ◽  
Author(s):  
F. LARDEUX ◽  
J. CHEFFORT

Developmental rates for Wuchereria bancrofti larvae maturing in the vector Aedes polynesiensis were estimated by analysing stage-frequency data consisting of counts of larval stages in mosquitoes reared at 20, 22·5, 25, 27·5, 30 and 32 °C. Base temperatures (i.e. low temperature thresholds) for W. bancrofti development were estimated by the x-intercept method and the model of Lactin et al. (1995). Resulting values were similar with both methods and were ≈12·5 °C for microfilariae (mf) in thorax, ≈17 °C for L1, 15·5 °C for L2 and 16·5 °C for L3. Upper thresholds estimated by the Lactin et al. model were 29·3 °C for mf, 29·1 °C for L1, 32·2 °C for L2 and 31·5 °C for L3. In addition, an original method was devised for computing the L3 upper threshold, by modelling L3 length shrinkage with temperature. It gave a value of 31·4 °C. At 32 °C, L2 and L3 stages exhibited altered morphology, larvae being shorter and wider than expected. The model of Lactin et al. described adequately the non-linear relationship between developmental rate and temperature, but a linear degree-day approach may be applied for temperatures below 27–28 °C.


2004 ◽  
Vol 16 (2) ◽  
pp. 144
Author(s):  
G.-S. IM ◽  
L. Lai ◽  
Z. Liu ◽  
Y. Hao ◽  
C.M. Murphy ◽  
...  

Although nuclear transfer (NT) has successfully produced cloned piglets, the development to blastocyst and to term is still low. Activation of the NT embryos is one of the key factors to improve the developmental ability of porcine NT embryos. Electric pulses as well as chemicals have been used to activate porcine NT embryos. This study was conducted to investigate the effect of continued activation following fusion pulses on in vitro development of porcine NT Embryos. Oocytes derived from a local abattoir were matured for 42 to 44h and enucleated. Ear skin cells were obtained from a 4-day-old transgenic pig transduced with eGFP recombinant retrovirus. Enucleated oocytes were reconstructed and cultured in PZM-3 in a gas atmosphere of 5% CO2 in air. Cleavage and blastocyst developmental rates were assessed under a stereomicroscope on Day 3 or 6. Blastocysts were stained with 5μg of Hoechst 33342 and total cell number was determined with an epifluorescent microscope. In Experiment 1, oocytes were activated with two 1.2kV/cm for 30μs (E) in 0.3M mannitol supplemented with either 0.1 or 1.0mM Ca2+. In each treatment, activated oocytes were divided into three groups. The first group was control (E). Other two groups were exposed to either ionomycin and 6-DMAP (E+I+D) or 6-DMAP (E+D) immediately after the electric pulses. In Experiment 2, fusion was conducted by using 1.0mM Ca2+ in the fusion medium. Fused NT embryos were divided into three treatments. NT embryos were fused and activated simultaneously with electric pulse as a control (C); the second group was treated with 6-DMAP immediately after fusion treatment (D0); and the third group was treated with 6-DMAP at 20min (D20) after fusion. In experiment 1, for 0.1mM Ca2+, developmental rates to the blastocyst stage for E, E+I+D or E+D were 12.5, 26.7 and 22.5%, respectively. For 1.0mM Ca2+, developmental rates to the blastocyst stage were 11.4, 28.3 and 35.6%, respectively. The activated oocytes treated with 6-DMAP following the electric pulses by using 1.0mM Ca2+ in fusion medium had higher (P<0.05) developmental rates to the blastocyst stage. In Experiment 2, developmental rates to the blastocyst stage for C, D0 or D20 were 10.0, 12.3, and 19.9%, respectively. Developmental rate to the blastocyst stage was higher (P<0.05) in D20. Fragmentation rates were 19.9, 10.8, and 9.0%, respectively. Regardless of Ca2+ concentration in fusion medium, continued treatments with chemicals following electric pulses supported more development of porcine activated oocytes. Treating NT embryos with 6-DMAP alone after fusion was completed by using 1.0mM Ca2+ in fusion medium improved the developmental rates to the blastocyst stage and prevented fragmentation accompanied by electric fusion. This study was supported by NIH NCRR 13438 and Food for the 21st Century.


2014 ◽  
Vol 6 (2) ◽  
pp. 644-648 ◽  
Author(s):  
K. Selvaraj ◽  
B. S. Gotyal ◽  
V. Ramesh Babu ◽  
S. Satpathy

Effect of six constant temperatures viz., 18±1, 21±1, 24±1, 27±1, 30±1 and 33±10C was studied on the egg hatchability, larval pupal development and adult survival of Spilarctia obliqua. Development rate of egg, larva and pupa gradually increased with increase in temperature, while total developmental period decreased. Mean developmental period of the pest decreased from 93.73 days at 18±10C to 31.20 at 33±10C. The lowest and the highest temperatures at which no development took place were found to be 12±10C and 39±10C, respectively. Regression equations between development rate and temperature were found to be Y= 0.0189 X -0.1998 (R2=0.88) for egg, Y=0.00122 X -0.0248 (R2=0.84) for small larva (1-3rd instar), Y=0.0058 X -0.0675 (R2=0.76) for large larva (4-6th instar), Y=0.0074 X-0.1075 (R2=0.94) for pupa and Y=0.0142 X-0.4363 (R2=0.79) for adults. Developmental threshold were determined to be 10.57, 11.27, 11.55, 15.28 and 10.92oC for egg, small larva, large larva, pupa, and adult respectively with corresponding thermal constant being 52.91, 344.82, 243.90, 142.85 and 70.42 degree days (DD). Thermal constant to complete a generation was found to be 854.90 DD. This was the first studies on this aspects, these estimated thermal thresholds and degree days could be used to predict the S. obliqua activity in the field for their effective management through pest forecasting.


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