Effect of temperature on the life history and demographic parameters ofSpalgis epius(Lepidoptera: Lycaenidae), a candidate biological control agent of mealybugs (Hemiptera: Pseudococcidae)

Abstract

Many species of mealybugs (Hemiptera: Pseudococcidae) are serious pests of economically important crops worldwide. We evaluated the influence of constant temperatures: 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 and 348C on the life history and demographic parameters of Spalgis epius (Lepidoptera: Lycaenidae), a candidate biological control agent of various species of mealybugs. No eggs completed their development at 14 and 348C. Egg-to-adult developmental time significantly decreased from 89.9 days at 168C to 20.4 days at 328C. The estimated lower temperature threshold of 10.28C and 416.6 degree-days were required to complete egg-to-adult development. The mortality of immature stages was maximum at 16 and 328C and minimum at 288C. The highest lifetime fecundity was recorded at 288C and it significantly decreased at 328C. The longevity of adults was about three times more at 168C than at 30 and 328C. The net reproductive rate (R 0 ) significantly increased with increased temperatures up to 288C and significantly decreased at 328C. The mean generation time (T) significantly decreased with increased temperature up to 308C, but it significantly increased at 328C. The intrinsic rate of population increase (r m ) was highest at 308C. The finite rate of increase (l) was significantly greater at 308C than at other temperatures. These data suggest that S. epius can develop, reproduce and survive in a wide range of temperatures and thus could be regarded a potential biological control agent of mealybugs.

Population dynamics ofSpalgis epius(Lepidoptera: Lycaenidae), a candidate biocontrol agent of mealybugs and its interaction with mealybug-attendant ants

“…Butterfly phenology is known to be sensitive to climatic changes; emergence dates, flight periods and number of broods have all been related to trends in warming (Roy & Sparks, 2000;Stefanescu, Peñuelas, & Filella, 2003). A significant negative correlation between an S. epius population and temperature suggests that an S. epius population decreases with increasing temperature as reported by Dinesh and Venkatesha (2012). However, Vinod Kumar et al (2007) reported that an S. epius population was positively correlated with rising temperature.…”

“…S. epius occurs in India, Burma, Sri Lanka, Philippines, Java, Bangladesh, Thailand, and Krakatau Island (Indonesia) (see Dinesh & Venkatesha, 2011a). Studies on the biology, mating and oviposition behaviour, feeding potential, mass rearing, effects of temperature on the life cycle and inter-and intraspecific interactions of S. epius have been conducted (Dinesh & Venkatesha, 2011a, 2011b, 2012, 2013a, 2013b, 2014Dinesh, Venkatesha, & Ramakrishna, 2010;Venkatesha, 2005;Venkatesha & Dinesh, 2011;Venkatesha & Shashikumar, 2006;Venkatesha, Shashikumar, & Gayathri Devi, 2004).…”

Inter- and intraspecific interactions in two mealybug predators Spalgis epius and Cryptolaemus montrouzieri in the presence and absence of prey

“…S. epius occurs in India, Burma, Sri Lanka, Philippines, Java, Bangladesh, Thailand and Krakatau Island (Indonesia) (see Dinesh & Venkatesha, 2011 a ). Studies on the biology, development, mating and egg laying behaviour, feeding potential and mass rearing of S. epius have been conducted (Venkatesha et al , 2004, 2005; Venkatesha & Shashikumar, 2006; Dinesh et al , 2010; Dinesh & Venkatesha, 2011 a , b , 2012, 2013 a , b ; Venkatesha & Dinesh, 2011). S. epius has four larval instars and completes its life cycle in 23.8 days at laboratory condition (Dinesh et al , 2010).…”