Life Table Parameters and Survivorship ofSpodoptera exigua(Lepidoptera: Noctuidae) at Constant Temperatures

Abstract

Age-specific life table parameters, survivorship, and extra molting of the beet armyworm, Spodoptera exigua (Hübner), were determined at eight constant temperatures of 12, 15, 20, 25, 30, 33, 34, and 36°C with a variation of 0.5°C on sugar beet leaves. No development was observed at 12 and 36°C. The survivorship of overall immature stages was higher at 25°C than the other temperatures. The highest (0.276 d(-1)) and lowest (0.149 d(-1)) value of the intrinsic rate of increase (r) was observed at 30 and 20°C, respectively. Although the highest value of the net reproductive rate was at 25°C (377.7 female offspring at 25°C and 127.4 female offspring at 30°C), the highest value of r was at 30°C, which indicated the importance of shorter development time (16.9 d at 30°C and 27.2 d at 25°C) in enhancing r. The relationship between temperature and r was modeled using the Lactin-2 model. The lower temperature threshold, the upper temperature threshold, and optimal temperature for the r were estimated at 13.1, 32.2, and 34.1°C, respectively. The mean generation time decreased significantly with increasing temperature, with the longest (35.9 d) and shortest (15.1 d) mean generation time was calculated at 20 and 33°C, respectively.

Cross tolerance in beet armyworm: long-term selection by cadmium broadens tolerance to other stressors

“…1). The confirmation to this explanation may be found also in the developmental table for S. exigua made by Karimi-Malati et al (2014) at various temperatures. The authors confirm that 25°C is optimal for S. exigua development, while the processes gets prolonged or shortened under, respectively, lower or higher thermal conditions.…”

“…Increased metabolic processes rate in higher temperature exposure may also result in a kind of trade-off between the heat shock protein synthesis and growth expenditures. Moreover, the authors stress that 36°C appeared to be a real stressing temperature (no development at all) while the temperature of 33°C caused the strongest reduction of the development time (by, nearly, 2 times) (Karimi-Malati et al 2014). Moreover, taking under consideration the fact that in the quoted experiment adult females reared under higher temperature conditions laid less eggs than the insects from the optimal temperature (25°C), we may suppose that the exposure to higher temperature requires various energy trade-offs that, probably, start even at younger (larval) developmental stages and they may be revealed by the lower level of HSP70 in the insects reared under 30°C.…”

Comparative Performance of Helicoverpa armigera (Lepidoptera: Noctuidae) on Chickpea and Faba Bean

“…Foundational to the development of IPM programs is a thorough understanding of pest species biology and ecology. The developmental, survivorship, reproduction and life table parameters of herbivorous insects are affected by temperature (Karimi-Malati et al, 2014;Soufbar et al, 2010;Karimi et al, 2012) and host plant quality (Naseri et al, 2011;Karimi et al, 2012). Life table analysis is a valuable tool for understanding how insect growth, developmental time, reproductive capacity, life expectancy and survival of insect populations contribute to overall population dynamics .…”

Genetically manipulated Brassica genotypes affect demography and performance of Diadegma semiclausum parasitizing Plutella xylostella

“…; Karimi‐Malati et al. ), the performance of the parasitoid was calculated using age‐stage, two‐sex life tables (Chi and Liu ; Chi ). In addition, several fitness correlates of the parasitoid (e.g.…”

“…To have a range of manipulated genotypes, we selected canola's progenitor (B. rapa) as a wild-type species, two cultivated canola cultivars (Opera and RGS 003 ), one hybrid (Hyula 401 ), one gamma irradiated genetic mutant-RGS 003 and PF, a transgenic genotype (that expresses a tolerance gene to herbicide), to represent high-and low-quality host plants that differ dramatically in GS content and previously were shown to significantly affect the performance of DBM (Nikooei et al 2015a). As life table studies provide details of survival, development and reproduction (Taghizadeh et al 2008;Golizadeh et al 2009a,b;Zahiri et al 2010;Karimi-Malati et al 2014), the performance of the parasitoid was calculated using age-stage, two-sex life tables (Chi and Liu 1985;Chi 1988). In addition, several fitness correlates of the parasitoid (e.g.…”