Two-sex life table and feeding dynamics ofSpilosoma obliquaWalker (Lepidoptera: Arctiidae) on three green gram cultivars

Abstract

The effect of three green gram cultivars (PDM 54, PUSA BAISAKHI and SAMRAT) on the biology of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) was studied using age-stage, two-sex life table. We also studied food utilization efficiency measures of larvae on green gram cultivars. The nutritional and antinutritional factors of leaves of green gram cultivars were determined. The preadult development time of S. obliqua was shortest on PDM 54 (35.54 days) and longest on SAMRAT (39.29 days). The fecundity was highest on PDM 54 (318.32) and lowest on SAMRAT (250.20). The net reproductive rate (R0) ranged from 37.53 on SAMRAT to 79.58 on PDM 54. The intrinsic rate of increase (r) was higher on PDM 54 (0.1148 day−1) and PUSA BAISAKHI (0.1018 day−1) than SAMRAT (0.0875 day−1). The finite rate of increase (λ) was lowest on SAMRAT (1.0915 day−1). Mean generation time (T) was shortest on PDM 54 (38.12 days) and longest on SAMRAT (41.42 days). Population projection revealed that the population growth was slowest on SAMRAT. The growth rate of sixth instar larvae was highest on PDM 54 and lowest on SAMRAT. The lower level of nutritional factors such as total carbohydrates, proteins, lipids, amino acids and nitrogen content, and a higher level of antinutritional factors such as total phenols, flavonols and tannins influenced higher development time and lower fecundity of S. obliqua on SAMRAT than other cultivars. These findings suggested that SAMRAT is a less suitable cultivar to S. obliqua than other cultivars, and this cultivar can be promoted for cultivation.

Comparative performance and digestive physiology ofDiaphania indica(Lepidoptera: Crambidae) onTrichosanthes anguina(Cucurbitaceae) cultivars

“…Different cultivars of a host plant play a crucial role in population growth and food utilization of insects (Golizadeh and Razmjou, 2010; Alami et al ., 2014; Nemati-Kalkhoran et al ., 2018; Mobarak et al ., 2020). Till date, no reports are available on D. indica using age-stage, two-sex life table, and further, the biology of D. indica on T. anguina is reported for the first time.…”

“…The intrinsic rate of increase ( r m ) and finite rate of increase ( λ ) can exactly predict the overall population growth, development and fecundity of an insect population, and are considered as important parameters in measuring population growth potential (Karimi-Pormehr et al ., 2018; Nemati-Kalkhoran et al ., 2018; Das et al ., 2019; Mobarak et al ., 2020). The r m was the lowest on Polo No.…”

“…1 than MNSR-1 and Baruipur Long could be another explanation for lower survivability of D. indica on Polo No. 1 (Mattson and Scriber, 1987; Roy and Barik, 2012, 2013; Mobarak et al ., 2020). The food consumed by the larvae of Lepidoptera could influence the reproductive potential of adults (Razmjou et al ., 2014).…”

“…Therefore, a host-plant resistant program is of considerable interest to achieve an efficient and safe control. Different cultivars of a host plant can differ in physiological and morphological characteristics including wax content, nutritional content as well as secondary metabolites (Golizadeh et al, 2017a(Golizadeh et al, , 2017bMobarak et al, 2020), which can affect the development, survival, longevity of adults, reproduction and fecundity of an insect pest.…”

“…Construction of life table is very useful to observe the development, survival and reproductive potential of an insect population, which is a popular method to measure various parameters of an insect and this, is necessary for the control of an insect pest (Chi and Getz, 1988; Southwood and Henderson, 2000; Zheng et al ., 2017). However, the traditional life table does not consider both sexes of an insect, while using age-stage, two-sex life table we can precisely determine the characteristics of an insect population such as stage differentiation, individual differences and male population (Chi, 1990; Chi and Su, 2006; Huang and Chi, 2011; Mobarak et al ., 2020).…”