Evaluation of different models to describe egg and pupal development of Xyleborus fornicatus Eichh, （Coleoptera： Scolytidae）, the shot-hole borer of tea in Sri Lanka

Development data of eggs and pupae ofXyleborusfornicatus Eichh. （Coleoptera： Scolytidae）, the shot-hole borer of tea in Sri Lanka, at constant temperatures were used to evaluate a linear and seven nonlinear models for insect development. Model evaluation was based on fit to data （residual sum of squares and coefficient of determination or coefficient of nonlinear regression）, number of measurable parameters, the biological value of the fitted coefficients and accuracy in the estimation of thresholds. Of the nonlinear models, the Lactin model fitted experimental data well and along with the linear model, can be used to describe the temperature-dependent development of this species.     

Estimating temperature‐dependent developmental rates of potato tuberworm,Phthorimaea operculella (Lepidoptera: Gelechiidae)

Abstract The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is the most destructive pest of potato, Solanum tuberosum L. (Solanaceae), in tropical and subtropical regions in both field and storeroom situations. The modeling of temperature‐dependent development can be useful in forecasting occurrence and population dynamics of the pests. Published developmental parameters for this pest vary greatly for many reasons. We determined temperature‐dependent development of P. operculella at seven constant temperatures (16, 20, 24, 28, 32, 34 and 36 °C). Developmental period of whole immature stage (egg to the end of the pupal stage) varied from 75.5 days at 16 °C to 17 days at 32 °C. The population failed to survive at 36 °C. The observed data was modeled to determine mathematical functions for simulating P. operculella development in each stage of development and overall. Two linear models, ordinary linear regression and the Ikemoto linear model were used to describe the relationship between temperature and development rate of the different stages of P. operculella and estimating the thermal constant and lower temperature threshold. The lower temperature threshold (t) and thermal constant (k) of whole immature stage were estimated to be 11.6 °C and 338.5 DD by Ikemoto linear model, and the estimated parameters were not substantially different with those estimated by ordinary linear models. Different models provided a better fit to the various developmental stages. Of the eleven nonlinear models fitted, the Beriere‐1, Logan‐6 and Lactin‐1 model was found to be the best for modeling development rate of egg, larva and pupa of P. operculella, respectively. Phenological models based on these findings can be part of a decision‐support tool to improve the efficiency of pest management programs.     

Effect of temperature on survival and immature development of Arma chinensis

Arma chinensis (Fallou) is a predaceous pentatomid with the potential to control a wide range of insect pests. In this study, the stage-specific temperature-dependent development and survival of A. chinensis was investigated under seven constant temperatures (range 18–35 °C) when fed with yellow mealworm (Tenebrio molitor L.). Developmental times (in days) for the immature stage, entire nymphal stage, and egg-to-adult development were inversely proportional to temperatures between 18 and 33 °C (30 °C for eggs and 1st instar nymphs). The lowest survival rate of A. chinensis was observed at 18 °C (6.7%), whereas it was the highest (80–93.3%) at temperatures ranging from 21 to 24 °C. The low temperature thresholds for the egg, entire nymph stage, and egg-to-adult development were 14.3, 12.28, and 12.8 °C, respectively, while the thermal constants for these stages were estimated to be 85.47, 334.9, and 423.8° days. Among the three non-linear models examined, the Taylor model showed the best fit for the egg data, the Briére1 model was the best fit for the 1st instar nymph stage, and the Lactin1 model was more approprate for all the other instar stages, the entire nymphal stage, and overall development. The upper temperature thresholds estimated using the Lactin1 model for eggs, overall nymphal stage, and egg-to-adult development were 38.57, 38.9, and 40.0 °C. The optimal temperature for the overall egg-to-adult period was estimated to be 33.5 °C. The results of this study can be used for the mass rearing of this natural pest enemy and development of phenology models of its seasonal progress.     

Temperature thresholds and thermal requirements for development of Nasonovia ribisnigri (Hemiptera: Aphididae)

Early detection of Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) on lettuce is of primary importance for its effective control. Temperature thresholds for development of this pest were estimated using developmental rates [r(T)] at different constant temperatures (8, 12, 16, 20, 24, 26, and 28 degrees C). Observed developmental rates data and temperature were fitted to two linear (Campbell and Mu?iz and Gil) and a nonlinear (Lactin) models. Lower temperature threshold estimated by the Campbell model was 3.6 degrees C for apterous, 4.1 degrees C for alates, and 3.1 degrees C for both aphid adult morphs together. Similar values of the lower temperature threshold were obtained with the Mu?iz and Gil model, for apterous (4.0 degrees C), alates (4.2 degrees C), and both adult morphs together (3.7 degrees C) of N. ribisnigri. Thermal requirements of N. ribisnigri to complete development were estimated by Campbell and Mu?iz and Gil models for apterous in 125 and 129 DD and for both adult morphs together in 143 and 139 DD, respectively. For complete development from birth to adulthood, the alate morph needed 15-18 DD more than the apterous morph. The lower temperature threshold determined by the Lactin model was 5.3 degrees C for alates, 2.3 degrees C for apterous, and 1.9 degrees C for both adult morphs together. The optimal and upper temperature thresholds were 25.2 and 33.6 degrees C, respectively, for the alate morph, 27 and 35.9 degrees C, respectively, for the apterous morph, and 26.1 and 35.3 degrees C, respectively, for the two adult morphs together. The Campbell model provided the best fit to the observed developmental rates data of N. ribisnigri. This information could be incorporated in forecasting models of this pest.     

Temperature‐dependent developmental model of Neoseiulus californicus (McGregor) (Acari,Phytoseiidae)

The developmental time and survival of immature stages of Neoseiulus californicus were studied at nine constant temperatures (12, 16, 24, 24, 28 32, 36, 38 and 40°C), 60–70% RH, and a photoperiod of 16 : 8 (L : D) h. The total mortality of immature N. californicus was lowest at 24°C (4.5%) and highest at 38°C (15.2%). The total developmental time decreased with increasing temperature between 12°C (18.38 days) and 32°C (2.98 days), and increased beyond 32°C. The relationship between the developmental rate and temperature was fitted by five nonlinear developmental rate models (Logan 6, Lactin 1, 2 and Briere 1, 2). The nonlinear shape of temperature development was best described by the Lactin 1 model (r² = 0.98). The developmental variation of each stage was well described by the three‐parameter Weibull distribution model (r² = 0.91–0.93). The temperature‐dependent developmental models of N. californicus developed in this study could be used to determine optimal temperature conditions for its mass rearing, to predict its seasonal population dynamics in fruit tree orchards or greenhouse crops, or to develop a population dynamics model of N. californicus.     

EFFECT OF TEMPERATURE ON THE DEVELOPMENT AND REPRODUCTION OF BEMISIA TABACI B BIOTYPE (HOMOPTERA: ALEYRODIDAE)

Abstract The development, survivorship and reproduction of Bemisia tabaci B biotype on eggplant at seven constant temperatures (17, 20, 23, 26, 29, 32 and 35°C) were studied. The developmental periods from egg to adult varied from 48.7 days at 17°C to 13.9 days at 29°C and the developmental threshold estimated for a generation by linear regression was 12.4°C. The optimum temperature for B. tabaci population growth was 26°C, both extremely low (< 17°C) and high temperature (> 32°C) delayed the development. Survivorships from egg to adult was 67.3% at 26°C, 27.6% and 29.0% at 35°C and 17°C respectively. The average longevity of females ranged from 39.6 days at 20°C to 12.8 days at 35°C. Oviposition per female varied from 164.8 eggs at 20°C to 78.5 eggs at 32°C. Both the longevity and oviposition of B. tabaci females at different temperatures were significantly different ( P < 0.05), and the intrinsic rate of natural increase ( r _m) for B. tabaci at 29°C was the highest.     

Temperature-dependent post-diapause development and prediction of spring emergence of the pine needle gall midge (Dipt., Cecidomyiidae)

Abstract:  We determined the influence of temperature on post-diapause development of overwintered Thecodiplosis japonensis Uchida et Inouye (Dipt., Cecidomyiidae) under various treatments (12, 15, 18, 21, 24, 27 and 30°C) in an effort to predict its spring emergence. Survival and developmental period for the overwintered larvae and pupae were significantly influenced by temperature. Linear and nonlinear regression models quantitatively described temperature-dependent development and survival of T. japonensis . The survival models exhibited right-skewed bell shape patterns for all stages, indicating a more detrimental impact on survival at high temperatures. Theoretical optimum temperatures with highest survival were 22.3, 24.0 and 24.0°C for the overwintered larvae, pupae and total post-diapause development (the larvae to adults) respectively. Pupal mortality was higher at all temperatures than larval mortality and the suitable range of temperature for pupae was narrower than that of larvae. The nonlinear Briere model estimated that optimum temperatures with the fastest development were 29.1°C for larvae, 27.6°C for pupae and 27.0°C for larvae to adults. In a linear model, the lower threshold temperatures were 5.1, 7.1 and 5.9°C for larvae, pupae, and larvae to adults respectively. A predictive degree-day model was developed using trap catches of T. japonensis adult emergence during 1991–1995. The model accounted for 84.6% of year-to-year variation in adult emergence and predicted accurately the median emergence time in 1996.     

Effect of temperature on the demography of Galerucella birmanica (Coleoptera: Chrysomelidae)

Studies on the effect of temperature on the development of the water chestnut beetle, Galerucella birmanica Jacoby were carried out in the laboratory at seven different temperatures: 16 °C, 19 °C, 22 °C, 25 °C, 28 °C, 31 °C and 34 °C. The developmental time decreased with increase in temperature. The developmental time at 16 °C, 19 °C, 22 °C, 25 °C, 28 °C, 31 °C and 34 °C was 96.60, 80.68, 58.96, 43.48, 35.03, 30.08 and 28.02 days for the period from egg hatching to adult emergence, respectively. The developmental threshold estimated for a generation by linear regression was 10.36 °C. The fecundity per female at 22 °C, 25 °C, 28 °C, 31 °C and 34 °C was 102.3, 134.5, 141.2, 130.1 and 116.2 eggs, respectively. Oviposition period ranged from 15.6 days at 22 °C to 8.6 days at 34 °C. Hatchability of eggs was highest at 31 °C with 76.9% and lowest at 34 °C with 57.1%. The highest generation survival rate was 65.3% at 31 °C, and the intrinsic rate of natural increase ( r _m) for G. birmanica was the highest at 34 °C.     

Effects of variable and constant temperatures on the embryonic development and survival of a new grape pest, Xylotrechus arvicola (Coleoptera: Cerambycidae)

Xylotrechus arvicola Olivier (Coleoptera: Cerambycidae) has become a new expanding pest in grape (Vitis spp.) crops. To better improve control tactics, the consequences of 11 constant (12, 15, 18, 21, 24, 27, 30, 32, 34, 35 and 36°C) and nine variable temperatures (with equal mean temperatures at each of the nine constant rates ranging from 15 to 35°C) on survival and embryonic development were studied. The eggs were able to complete development at constant temperatures between 15 and 35°C, with mortality rates at the extremes of the range of two and 81.5%, respectively. Using variable temperatures a mortality rate of 38.9% at a mean temperature of 15°C and 99% at 35°C was observed. The range of time for embryonic development was 29.5 d at 15°C to 6 d at 32°C at constant temperatures, and from 29.6 d at 15°C to 7.2 d at 32°C at variable temperatures. The goodness-of-fit of different development models was evaluated for the relationship between the development rate and temperature. The models that gave the best fit were the Logan type III for constant temperatures and the Brière for variable temperatures. Optimum temperatures were estimated to be from 31.7 to 32.9°C. The models that best described embryo development under natural field conditions were the Logan type III model for constant temperatures (98.7% adjustment) and the Lactin model for variable temperatures (99.2% adjustment). Nonlinear models predicted faster development at constant temperatures and slower development at variable ones when compared with real field development, whereas the linear model always predicted faster development than what actually took place.     

Modeling egg development of the pest Clavipalpus ursinus (Coleoptera: Melolonthidae) using a temperature‐dependent approach

Abstract Predicting the population dynamics of insects in natural conditions is essential for their management or preservation, and temperature‐dependent development models contribute to achieving this. In this research the effects of temperature and soil moisture content on egg development and hatching of Clavipalpus ursinus (Blanchard) were evaluated. The eggs were exposed to seven temperature treatments with averages of 7.2, 13.0, 15.5, 19.7, 20.6, 22.0 and 25.3°C, in combination with three soil moisture contents of 40%, 60% and 80%. A linear and two non‐linear (Lactin and Briere) models were evaluated in order to determine the thermal requirements of this developmental stage. Temperature affected significantly the time of development and egg hatching, while no significant effect was observed for moisture content. Thermal requirements were set as: 7.2°C for lower developmental threshold, 20.6°C for optimum developmental threshold, 25.3°C for maximum temperature and 344.83 degree‐days for the thermal constant. The linear model described satisfactorily egg development at intermediate temperatures; nevertheless, a slightly better fit of the observed data was obtained with the Lactin model. Egg development took place inside a narrow range of temperatures. Consequently, an increment of soil temperature could generate a negative impact on the population size of this species or changes in its biological parameters.     

Temperature-dependent development and oviposition models of Ramulus irregulariterdentatus (Phasmida: Phasmatidae)

Public interest in Ramulus irregulariterdentatus as a pet insect in Korea is increasing, although it is also considered as a potential forest insect pest. The objective of this study was to construct development and oviposition models of R. irregulariterdentatus. Development rates were fitted with a nonlinear Briére model which estimated optimal temperatures to be 24.5 and 26.2?°C with upper development thresholds of 29.3 and 31.4?°C for egg and nymph, respectively. In a linear model, lower development thresholds were 7.6 and 5.2?°C for egg and nymph, respectively. Survivorship was the highest at 21.0 and 22.2?°C for egg and nymph, respectively. Mean fecundity ranged from 14.4 eggs at 17.5?°C to 32.0 eggs at 23.5?°C. It was fitted to an extreme value function. Adult survival and cumulative oviposition rate of R. irregulariterdentatus were fitted to a sigmoid function and a two-parameter Weibull function, respectively. These models can be used to forecast phenology and population dynamics of R. irregulariterdentatus in the fields and optimize environmental conditions for rearing R. irregulariterdentatus.     

Effect of temperature on the biology of Creontiades dilutus (Stål) (Heteroptera: Miridae)

The egg and nymphal development, fecundity and survival of the green mirid, Creontiades dilutus were examined at a range of temperatures and a modified day-degree model fitted to the data. Day degree (DD) requirements for egg and nymphal development, and threshold temperatures were calculated from the fitted lines. Female fecundity and longevity, egg and nymphal development, and survival of C. dilutus were significantly influenced by temperature. Eggs and nymphs failed to complete development at temperatures below 17 and at 38°C. Females also failed to produce any eggs at 11 and 38°C. The optimum temperature range for female fecundity was found to be 26–32°C. The optimum temperature for the development of eggs was calculated from the model as 30.5°C and for nymphs as 31.5°C. The threshold temperature for development was 15.8°C for egg and 15.1°C for nymph; 69.4 and 156.7 DD were required for completing the egg and the nymphal development, respectively. At the optimum temperature, it was estimated that development from egg to adult took 15 days. Survival was highest at 26°C for eggs and at 30–32°C for nymphs.     

Life history of Amitus fuscipennis (Hym., Platygastridae) as parasitoid of the greenhouse whitefly Trialeurodes vaporariorum (Hom., Aleyrodidae) on tomato as function of temperature

Life history parameters of Amitus fuscipennis MacGown and Nebeker as parasitoid of Trialeurodes vaporariorum (Westwood) were determined at 15, 20, 25 and 30°C on tomato using three different methods. For each method, immature development, mortality, longevity, fecundity, oviposition frequency and post-oviposition period were determined and temperature-dependent relations were estimated. Oviposition frequency was also estimated as a function of parasitoid age. Immature development had a maximum of 61 days at 15°C that decreased to 22 days at 30°C. Mortality in the grey stage was less than 2% at temperatures lower than 30°C, where it was 60%. Longevity fluctuated between 3 and 18 days. Fecundity increased from 338 eggs/female at 15°C to a maximum of 430 eggs/female at 25°C and then decreased to 119 eggs/female at 30°C. Oviposition frequency varied between 3 and 46 eggs/female per day and had its maximum on the first day after emergence of the parasitoid. Net reproduction rate, generation time and intrinsic rate of increase were calculated. The intrinsic rate of increase increased from 0.090 at 15°C to a maximum of 0.233 at 25°C and then decreased to 0.159 at 30°C. The influence of the methods to determine the life history parameters on the results is discussed. The results are compared also with the life history of Encarsia formosa Gahan (Hym., Aphelinidae) a parasitoid of the same host. The advantages and disadvantages of the pro-ovigenic A. fuscipennis in comparison with the synovigenic E. formosa are discussed.     

Effects of temperature, sorbitol, alanine and diapause hormone on the embryonic development in Bombyx mori: in vitro tests of old hypotheses

Abstract.  An in vitro culture method is described in which embryonic development in Bombyx mori is traced at various temperatures and treatments. The results show that the induction, intensification and termination of diapause are distinct processes. Prediapause embryos, explanted from 40-h-old diapause-destined eggs and cultured in Grace's medium, continue to develop to the appendage-formation stage without arrest, which indicates that the isolated embryos have not entered diapause, whereas the development of embryos from diapausing eggs (15 days after being laid) is significantly slower. The rate of development of embryos dissected from diapause eggs increases during chilling (5 °C) and incubation (at 25 °C) gradually during chilling and dramatically at 25 °C. The in vitro experiments also reveal that sorbitol directly inhibits the development of embryos explanted from diapausing eggs but has no affect on the development of embryos from prediapause eggs. Neither alanine nor diapause hormone prevent isolated embryos from developing.     

Effect of temperature on development and survival of the parasitoid Pnigalio pectinicornis (Hymenoptera: Eulophidae) reared on Phyllocnistis citrella (Lepidoptera: Gracillariidae)

Laboratory studies were conducted to assess the effect of temperature on the development and survival of the indigenous parasitoid Pnigalio pectinicornis L. on the citrus leaf miner Phyllocnistis citrella Stainton as host, fed on leaves of Citrus sinensis L. Osbck cultivar Washington navel and Citrus reticulata Blanco cultivar Clementine. Experiments were conducted at five constant temperatures ranging from 15 to 32.5 degrees C, with 60 +/- 10% RH and a photoperiod of 14:10 (L:D) h. The relationship between the developmental rate and temperature was determined using both linear and nonlinear (Lactin's formula) models. Developmental time of immature stages tended to be shorter as the temperature increased the range from 15 to 30 degrees C. Mortality was greater at the temperatures extreme tested. Both linear and nonlinear models provided a reliable fit of developmental rates versus temperature for all immature stages. Developmental thresholds that were estimated by the linear model for eggs were higher than those estimated by the nonlinear model. However, higher values of the low developmental threshold for larva and pupa stage of P. pectinicornis were estimated by the Lactin-2 model than that by the linear model. The potential of these models to predict the phenology of this parasitoid and its biological characteristics found in this study are discussed for its proper use as a biological control agent.     

用非线性模型估测恒温和变温下棉铃虫蛹的发育率

为了深入分析和探讨昆虫发育与环境温度的关系, 在恒温（15~37℃）和交替变温（12/18~34/40℃）下测定了棉铃虫Helicoverpa armigera蛹的发育历期(d),分别用线性模型和非线性模型（Logan模型﹑Lactin模型和王氏模型）拟合其发育率(1/d)数据。结果表明,这3个非线性模型能更准确地描述发育率与温度之间的曲线关系,判定系数（R2）在0.9878～0.9991之间。对全部观测数据的进一步研究表明,只要有6个分布合适的观测数据,就可以用这些非线性模型获得相当满意的估测效果。如果缺乏高温下的测定数据,用非线性模型预测的昆虫发育率可能失真。分析了蛹在恒温和变温下发育率差异的可能原因,讨论了应用这3个非线性模型预测蛹期发育的优点和缺点,指出用非线性模型取代线性日·度模型进行害虫发生预测和益虫饲养管理的合理性和必要性。     

Fertility life table of Trichogramma pretiosum (Hym., Trichogrammatidae) in eggs of Tuta absoluta and Phthorimaea operculella (Lep., Gelechiidae) at different temperatures

Abstract: The aim of this work was to study the reproductive potential of Trichogramma pretiosum reared on Tuta absoluta and Phthorimaea operculella eggs through fertility life tables at different temperatures. The development cycle and the parasitization capacity of this parasitoid was determined in order to calculate the net reproductive rate ( R _o), the infinitesimal increase ratio ( r _m), the finite increase rate ( λ ) and the mean duration of the generation ( T ). The mean duration of one generation of T. pretiosum kept on both eggs was observed to show an inverse relation with the increase of temperature. The net reproduction rate varied according to the temperature variation for both species. The maximum increase in capacity of T. pretiosum on the first host ( T. absoluta ) was reached at 22°C and on the second host ( P. operculella ) between 22 and 25°C. The infinitesimal increase rate and the finite increase rate for both moths had a relationship with the increase of temperature ranging from 18 to 30°C. The highest value of λ for both moths occurred at 30 and 32°C according to the lesser duration of a generation.     

Temperature-dependent development and reproduction of the boll weevil (Coleoptera: Curculionidae)

Abstract Effects of temperature on development, survival, and fecundity of boll weevil, Anthonomus grandis grandis Boheman, were assessed at 10, 11, 12, 15,20,25,30,35,45, and 46 °C; 65% relative humidity; and a photoperiod of 13:11 (L: D) h. The mortality of boll weevil immature stages was 100% at 12°C and decreased to 36.4% as the temperature increased to 25°C. When the temperature increased from 30 °C to 45 °C, the mortality of weevils also increased from 50.1% to 100%. From 15°C to 35°C, the bollweevilpreimaginal development rate was linearly related to temperature. The average development time of total boll weevil immature lifestages decreased 3.6-fold and the preovipositional period decreased 3.3-fold when the temperature was increased from 15°C to 30°C. The lower threshold for development was estimated at 10.9, 6.6, 7.0, and 9.0 °C for eggs, larval, pupal, and total immature stages, respectively, with total thermal time requirement to complete immature stages of 281.8 DD (degree day) (15°C) and 247.8 DD (35 °C). At 1LC and 46°C, weevil females did not oviposit. Longevity of adult females decreased 4.6-fold with increasing temperatures from 15°C to 35°C. Fecundity increased with increasing temperatures up to 30°C and significantly decreased thereafter. These findings will be useful in creating a temperature-based degree-day model for predicting the occurrence of key life stages in the field. An accurate predictor of a pest's development can be very important in determining sampling protocols, timing insecticide applications, or implementing an integrated pest management control strategy targeting susceptible life stages.     

Modelling temperature-dependent bionomics of Bemisia tabaci (Q-biotype)

Abstract.  The influence of temperature (17, 21, 25, 30 and 35 °C) on life-history traits of a Q-biotype Bemisia tabaci population on tomato is studied. Temperature-dependent relationships are characterized for immature developmental rate, immature survival, fecundity, longevity and intrinsic rate of increase. Development time vary from 20 days at 30 °C to 56 days at 17 °C and the lowest thermal threshold is estimated at 10.2 °C. The optimal temperature for immature development is 32.5 °C. Total fecundity (eggs per female) ranges from 105.3 (at 21 °C) to 41 (at 35 °C). The longevity decreases with temperature increase. The intrinsic rate of increase ranges from 0.0450 (at 17 °C) to 0.123 (at 30 °C). The functional relationships between temperature and life-history parameters are used to evaluate the effect of temperature on the population dynamics. Such mathematical relationships could provide a basis for future development of population models.