Lactin Model Research Articles

Age-Specific Life Table Parameters and Survivorship of an Iranian Population of the Codling Moth (Lepidoptera: Tortricidae) at Different Constant Temperatures

Abstract Age-specific life table parameters and survivorship, adult longevity, reproduction periods, fertility, and sex ratio of the codling moth were studied at eight constant temperatures (10, 14, 20, 25, 27, 30, 33, and 35 ±0.5°C). Among the examined temperatures, the highest values of net reproductive rate, intrinsic rate of increase, and finite rate of increase were 18.28 (females/female), 0.08 (females/female/d), and 1.08 at 27°C, respectively. Similarly, the highest value of sex ratio was 0.56 [females/ (females + males)] at 27°C. The highest mean generation time and doubling time were 72.26 and 23.09 d, respectively, at 20°C. To present a suitable model for intrinsic rate of increase at different temperatures, a nonlinear Lactin model was fitted to our observations. The longest preoviposition period was 2.77 and 2.55 d at 20 and 30°C, respectively. Also, the longest oviposition period was 8.46 d at 20°C. Postoviposition period was not statistically different at examined temperatures. The Weibull frequency distribution was used to describe the age-specific survival of the female adults. Based on the Weibull distribution parameters, the survival curves were type I at all examined temperatures, which indicates that mortality mostly occurred in old individuals. These findings confirmed that temperature is a critical environmental factor affecting codling moth population growth.

Temperature-dependent development and oviposition models of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae)

The temperature-dependent development, survival, longevity, and reproduction of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae) were studied at constant temperatures in the laboratory. The mean developmental time from egg to adult emergence ranged from 18.8 d at 36.7°C to 67.0 d at 19.7°C and the lower temperature threshold for the total immature stage (egg to adult emergence) was 15.0°C. The nonlinear shape of temperature-dependent development was well described by the Lactin model. The standardized cumulative frequency distributions of developmental times for each life stage were fitted to the two-parameter Weibull function. Mean adult longevity ranged from 7.83 d at 34°C to 165.14 d at 17.5°C. Mean total fecundity ranged from 29.2 eggs at 34°C to 456.4 eggs at 25°C and was fitted to the extreme value function. Adult survival and the cumulative oviposition rate of R. clavatus were fitted to the sigmoid and two-parameter Weibull function, respectively. We anticipate that the fitted models and parameters will be useful in developing a population model for R. clavatus.

Reproduction, longevity and life table parameters of Tyrophagus neiswanderi (Acari: Acaridae) at constant temperatures

The astigmatid mite Tyrophagus neiswanderi Johnston and Bruce is mainly considered a pest of ornamental and horticultural crops. However, this mite has been found infesting Cabrales cheese in Spain, though its population density is low compared to Acarus farris, the prevalent species of astigmatid mite encountered in Cabrales cheese maturing caves. One of the factors that might be influencing this differential abundance is temperature. In the present study the effect of temperature on reproductive parameters and longevity of T. neiswanderi was examined at six constant temperatures, ranging from 10 to 31 degrees C, and a relative humidity of 90 +/- 5%. Preoviposition period, fecundity and daily fecundity were adversely affected by extreme temperatures while the oviposition period increased as temperature was reduced. Male and female longevity increased as temperature decreased, but males showed significantly greater longevity than females. Additionally, this difference was greater as temperature decreased. The effect of temperature on the intrinsic rate of natural increase of T. neiswanderi populations was described by the non-linear Lactin model. The optimum temperature for development was predicted at 26.6 degrees C. At this temperature, the population doubling time is 2.8 days. The lower and upper thresholds for T. neiswanderi populations were calculated at 7.4 and 31.7 degrees C, respectively. According to these results, the influence of temperature on the low population density of this mite found in Cabrales maturing caves compared with A. farris is discussed.

Temperature Thresholds and Thermal Requirements for Development ofNasonovia 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°C). Observed developmental rates data and temperature were fitted to two linear (Campbell and Muñiz and Gil) and a nonlinear (Lactin) models. Lower temperature threshold estimated by the Campbell model was 3.6°C for apterous, 4.1°C for alates, and 3.1°C for both aphid adult morphs together. Similar values of the lower temperature threshold were obtained with the Muñiz and Gil model, for apterous (4.0°C), alates (4.2°C), and both adult morphs together (3.7°C) of N. ribisnigri. Thermal requirements of N. ribisnigri to complete development were estimated by Campbell and Muñiz 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°C for alates, 2.3°C for apterous, and 1.9°C for both adult morphs together. The optimal and upper temperature thresholds were 25.2 and 33.6°C, respectively, for the alate morph, 27 and 35.9°C, respectively, for the apterous morph, and 26.1 and 35.3°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 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 Muñiz 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 Muñiz 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 Muñiz 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.

Effect of temperature on reproductive parameters and the longevity of Acarus farris (Acari: Acaridae)

Reproductive parameters and the longevity of Acarus farris were examined at six constant temperatures, ranging from 7 to 29 °C, and a relative humidity of 90±5%. As temperature increased, the preoviposition period rapidly decreased to a minimum, above 25 °C. Fecundity was adversely affected by extreme temperatures while the oviposition period increased as temperature was reduced. The relationship between reproductive parameters and temperature was fitted using different polynomial and non-linear models. Male and female longevity increased as temperature decreased, except for the males at 7 °C, which showed significantly lower longevity than at 10 °C. Moreover, males showed significantly greater longevity than females. The effect of temperature on the capacity for increase of A. farris populations was also established. The non-linear Lactin model provided a reliable fit of the relationship between intrinsic rate of increase and temperature ( R 2>0.99). The optimum temperature for development was calculated to be 25 °C. At this temperature, the population doubling time was 2.8 days. The lower and upper thermal thresholds for A. farris populations were established at 6.4 and 29.9 °C, respectively.

Temperature and development rate of Triatoma guasayana (Hemiptera: Reduviidae) eggs under laboratory conditions: physiological and adaptive aspects

Abstract Eggs laid in the laboratory by T. guasayana (Wygodzinsky & Abalos 1949) adults collected from wild biotopes in Santiago del Estero (Argentina) were exposed to fluctuating temperatures, and 172 egg batches, involving 1574 eggs, completed development. Their development times were fitted to the linear degree‐day model and three nonlinear models (devar, Lactin, and Rueda). Parameter values and 95% CL were estimated. The lower development threshold is estimated to be 15 °C (linear devar model) and 17.5 °C (Lactin model), and the temperature resulting in the shortest development time is estimated to be between 26 °C (Lactin model) and 37 °C (nonlinear devar model). The thermal death point by the Lactin model is 34.4 °C, and conforms well with other studies. Differences between the present results and those of other studies for T. guasayana are discussed in terms of the maternal effects, the influence of experimental conditions, and the rate summation effect. Using the climatic conditions of the natural environment of T. guasayana, the results are interpreted in terms of physiological adaptation. A generalized development rate response of T. guasayana eggs to increasing temperature is proposed, with three ranges: between 10 and 14.8 °C development rate increases in an accelerating way; between 14.8 and 29.2 °C development rate increases more or less linearly, and between 29.2 and 34 °C development rate decreases.

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

Abstract Development data of eggs and pupae of Xyleborus fornicatus 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.

Development and survival of the cheese mites, Acarus farris and Tyrophagus neiswanderi (Acari: Acaridae), at constant temperatures and 90% relative humidity

Two species of acarid mites, Acarus farris and Tyrophagus neiswanderi, have been identified infesting Cabrales cheese in an Asturian maturing cave, the former being the prevalent species. The developmental rate and survival of immature stages of these mites were examined at constant temperatures, ranging from 7 to 29.7 °C for A. farris, and 10 to 31 °C for T. neiswanderi, and a relative humidity (r.h.) of 90±5%. The larval stage of A. farris was particularly susceptible to low and high temperatures with 81.7% and 95.2% mortality at 7 and 29.7 °C, respectively. Tyrophagus neiswanderi larvae also showed the greatest mortality at extreme temperatures among immature stages, though at a lower level than for A. farris (8.6% and 25.6% at 10 and 31 °C, respectively). The optimal temperature for development appeared to be 27–28 °C for both species and the developmental rates were higher for A. farris than T. neiswanderi within the range of the cooler temperatures prevalent in the cheese-maturing caves. The nonlinear Logan type-III model provided the best fit for the relationship between developmental rates and temperature ( R a 2>0.99) for all immature stages of A. farris, whereas the development of T. neiswanderi was better described by the Lactin model ( R a 2>0.97). The lower and upper developmental threshold temperatures predicted for each stage of A. farris were 3–4 °C lower than those predicted for T. neiswanderi. The differential temperature-development rate for each species might explain the greater abundance of A. farris compared to T. neiswanderi. Furthermore, manipulation of temperature based on modeling predictions may well be used to control mite populations during the cheese maturing process.

Effect of temperature on reproductive parameters and longevity of Tyrophagus putrescentiae (Acari: Acaridae)

The effect of temperature on reproductive parameters and longevity of the mold mite, Tyrophagus putrescentiae (Schrank) was examined at seven constant temperatures, ranging from 10 to 34 degrees C, and a relative humidity of 90 +/- 5%. Preoviposition period and fecundity were adversely affected by extreme temperatures and the oviposition period increased as temperature was reduced. Different patterns were observed for longevity data for males and females, with greater longevities for males at intermediate temperatures and more similar values for both sexes at extreme temperatures. Polynomial and non-linear models provided a good fit of the relationship of reproductive and longevity parameters with temperature. The effect of temperature on the intrinsic rate of increase of T. putrescentiae populations was established by the non-linear Lactin model. The optimum temperature for development was obtained at 30 degrees C. At this temperature, the population doubling time is 1.75 days. The lower and upper thresholds for T. putrescentiae populations were established at 10.4 and 34.8 degrees C, respectively. Altogether, these data provide basic information to develop sound physical control strategies of the mold mite.

Comparative Temperature-Dependent Development ofNephus includens(Kirsch) andNephus bisignatus(Boheman) (Coleoptera: Coccinellidae) Preying onPlanococcus citri(Risso) (Homoptera: Pseudococcidae): Evaluation of a Linear and Various Nonlinear Models Using Specific Criteria

The effect of temperature on the development of the predators Nephus includens (Kirsch) and Nephus bisignatus (Boheman) (Coleoptera: Coccinellidae) was studied. The duration of the development of immature stages and the pre-oviposition period of the two predators, reared on Planococcus citri (Risso) (Homoptera: Pseudococcidae) at eight constant temperatures (10, 15, 20, 25, 30, 32.5, 35, and 37.5 ± 1°C), have been recorded. The developmental zero (lower temperature threshold) was estimated to be 10.9 and 9.4°C, and the thermal constant was 490.5 and 614.3 DD for N. includens and N. bisignatus, respectively, using the linear model. Data were fitted to various nonlinear temperature-dependent models, and the thermal developmental thresholds (lower and upper), as well as the optimum temperature for development, have been estimated. Evaluation of the models took place, based on the following criteria: fit to data (residual sum of squares and coefficient of determination or coefficient of nonlinear regression), number and biological value of the fitted coefficients, number of measurable parameters, and accuracy on the estimation of the thresholds. Conclusively, linear and Lactin models are highly recommended for the description of temperature-dependent development of these two predators and possibly of other coccinellids.

Development and Survival ofTyrophagus putrescentiae(Acari: Acaridae) at Constant Temperatures

The developmental rate and survival of immature stages of mold mite, Tyrophagus putrescentiae (Schrank), were examined at seven constant temperatures, ranging from 10 to 34°C, and a relative humidity of 90 ± 5%. The larval stage was particularly susceptible to low and high temperatures with 93.6 and 54% mortality at 10 and 34°C, respectively. The optimal temperature for development and survival appeared to be 30°C. Three nonlinear (Logan type III, Lactin, and Briere) models provided a reliable fit of the relationship between developmental rates and temperature (Ra2 > 0.93) for all immature stages. The upper threshold predicted by the three models were similar for all developmental stages, ranging from 35.5°C (larvae) to 37.4°C (eggs). In contrast, the lower threshold was greater using the Briere (8.8–10.5°C) model compared with the Logan type III and Lactin model for all stages. Both Lactin and Logan III predicted similar lower threshold, though it was lower for Logan III (4.4–7.3°C) for all stages, except for the larvae, where both models predicted the same temperature threshold (6.1°C). The low thermal variations of the environments where T. putrescentiae live have probably favored similar thermal threshold variations in the different immature stages. The potential of these models to predict the development of this mite is discussed.