Effect of temperature on the development, fecundity, progeny sex ratio and life-table of Campoletis chlorideae, an endolarval parasitoid of the pod borer, Helicoverpa armigera

Abstract

Effect of temperature on the development, fecundity, progeny sex ratio and life-table of Campoletis chlorideae, an endolarval parasitoid of the pod borer, Helicoverpa armigera Abstract Development, survival, fecundity, progeny sex ratio (PSR) and age-specific life-table parameters of the parasitoid Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) were examined at six different constant temperatures (12, 17, 22, 27, 32 and 378C) in the laboratory [70 ± 10% RH and 10:14 h (light:dark) photoperiod]. Second instar larvae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) were reared on chickpea (Cicer arietinum L.) and used as the host. Development times shortened as the temperature increased from 12 to 378C. The estimated lower developmental threshold (tL) was 3.48C. The thermal summation for total immature stages was 379.97 degree-days. A reciprocal relationship between temperature and longevity was observed in the range of 12-178C. The maximum mortality of pupae (71.8%) occurred at 378C. At 228C, the yield of a female parasitoid averaged 137.3 ± 14.7 (mean ± SD) progeny, of which 89.6 ± 7.6 were daughters. The number of daughters produced decreased when the females were kept either above or below 228C, although the PSR was female biased in the range of 17-278C. The analyses of life-table parameters, developmental rates, reproduction, mortality and PSR suggest that maximum population growth (r m ) is near 278C. There was little variation observed in most of the desired qualities of C. chlorideae in the range of 17-278C, and it appears that the parasitoid is adapted to a wide range of temperatures. We suggest that for maximum production the parasitoid should be reared at 22 ± 48C and be released in areas where the temperature ranges between 178 and 278C, as in the plains of northern India.

Variable temperatures across different stages have novel effects on behavioral response and population viability in a host-feeding parasitoid

“…All immature stages of E. hayati exhibited the same temperature-dependent trend in duration: shorter developmental stages at higher preadult temperatures. This is consistent with other temperature-dependent studies on parasitoids, such as Encarsia citrina Craw 33 , Microplitis manilae Ashmead 23 , Trichogramma pretiosum Riley 32 and Campoletis chlorideae Uchida 22 . It is likely a common rule that the development rate of parasitoids, typically ectothermic insects, increases with temperature because the impacts of increased temperature on insect performance depend on the ambient temperature and its difference from the insects’ optimal temperature.…”

“…Many previous studies have compared the life table parameters of parasitoids at different constant temperatures to identify the best intrinsic rate of increase ( r ) 18,19,21–25 . The developmental rates of larval parasitoids usually increase monotonically with temperature, showing a monotonic left-skewed pattern, while reproduction/fecundity shows a symmetrical unimodal pattern 3,22–28 . This suggests that larval development and adult fecundity respond differently to temperature increases.…”

“…Furthermore, as one of the most important population parameters in life table studies, r is strongly influenced by the duration of time from birth to the start of reproduction and, to a lesser extent, by survival and reproduction rates 22,28 , . Hence, it is not reasonable to choose the best r value by directly comparing them among different constant temperatures over an entire generation, as the net effect of temperature on parasitoid fitness should depend on its relative influence on the immature and adult stages 22–29 . However, surprisingly few studies have considered thermal variation across different life stages 9,10 .…”

Reproduction of Trichospilus diatraeae (Hymenoptera: Eulophidae) with Different Densities and Parasitism Periods in Anticarsia gemmatalis (Lepidoptera: Noctuidae) Pupae

“…Sex ratio variations may be beneficial or detrimental to biological control programs (BARBOSA et al 2016), but larger female numbers must be sought, since males are not parasitic (PANDEY & TRIPATHI 2008). Moreover, the number of females produced is important to maintain and increase the population of natural enemies (HEIMPEL & LUNDGREN 2000).…”

Effects of parental age at mating on the fecundity and progeny sex ratio of Campoletis chlorideae, an endolarval parasitoid of the pod borer, Helicoverpa armigera

“…It seems therefore that the control strategy of this pest must be biointensive. Currently, implementations are being made on the use of Campoletis chlorideae Uchida to control the H. armigera population on chickpea in India (Pandey and Tripathi 2007).…”