Developmental Times and Life Table Statistics ofAulacorthum solani(Hemiptera: Aphididae) at Six Constant Temperatures, With Recommendations on the Application of Temperature-Dependent Development Models

Abstract

Aulacorthum solani (Kaltenbach) (known as foxglove aphid or glasshouse potato aphid) is a pest of increasing economic importance in several agricultural crops worldwide, including greenhouse vegetables and ornamentals. Developmental rates and age-specific life tables for a North American population of A. solani on pansy (Viola × wittrockiana) (Gams.) were determined at six constant temperatures, and comparisons were made to previous studies of A. solani from differing geographic regions and host crops. On pansy, A. solani developed fastest at 25°C, passing through the four nymphal instars in an average of 6.9 d. The highest intrinsic rates of population increase (0.410 and 0.445) and shortest population doubling times (1.69 and 1.56 d) were recorded at 20 and 25°C, respectively. Average total fecundity remained high from 10 to 20°C (74-68 nymphs/adult); a significant decrease to 39 nymphs/adult occurred at 25°C. For calculating developmental thresholds, we present here a method of adjusting the lower developmental threshold (t(min)) using estimates from nonlinear models to provide an improved estimate of the thermal constant (K, in degree-days). We also call attention to the necessity of using a simulation method to estimate the true upper developmental threshold (t(max)) and optimum developmental temperature (t(opt)) from the Lactin-2 model of temperature-dependent development.

Survival and Fecundity of Two Strains ofCimex lectularius(Hemiptera: Heteroptera)

“…Numerous studies have used life tables to describe the development of hemipterans (Landahl and Root 1969, Hough-Goldstein and McPherson 1996, Jandricic et al 2010), yet bed bugs have been studied only once (Polanco et al 2011a). Life tables and fertility rates represent baseline information that allows researchers to evaluate population growth and determine population age structure and the reproductive contribution of femalesÕ to future generations (Andrewartha and Birch 1954 Colonies of both strains were maintained at the Pennsylvania State University in State College, PA.…”

Developmental Biology of an Exotic Scale, <I>Acutaspis albopicta</I> (Hemiptera: Diaspididae)

“…Lactin et al (1995) noted that their modiÞca-tions of the Logan model (adding the parameter ) produced estimates of T max that were as much as 5ЊC higher than the original Logan model (without the parameter ). Subsequent authors (i.e., Diaz et al 2007, Jandricic et al 2010) also discovered that T max values estimated in the Lactin model were higher than the actual temperature at which development stops. As a result, true developmental thresholds predicted by the model can be obtained only by simulation, in this case using the Lactin model to calculate the predicted developmental rates as a function of temperatures in addition to those used in this study (15, 20, 25, and 30ЊC) from 0 to 39ЊC at every 0.05ЊC increment.…”

Thermal Requirements and Development of <I>Herpetogramma phaeopteralis</I> (Lepidoptera: Crambidae: Spilomelinae)

“…For the prepupal stage in Briere-2, we used the NewtonÐRaphson algorithm because the parameters were not highly correlated (Ͼ0.8 or ϽϪ0.8). For Lactin-2, parameter estimates were derived by simulation method where developmental rate (1/d) was 0 for T 0 and T L (identifying upper and lower thresholds intersecting the x-axis), whereas T opt was obtained when developmental rate was maximized (Jandricic et al 2010). Linear models were Þtted using PROC REG (SAS Institute 2008).…”