Consequences of diapause on post‐diapause development, reproductive physiology and population growth of Chilo partellus (Swinhoe)

Abstract

We investigate the effects of diapause on post‐diapause development, reproductive physiology and population growth of Chilo partellus (Swinhoe) (Crambidae: Lepidoptera). Aestivating and hibernating larvae of C. partellus are exposed to diapause terminating conditions (consisting of an LD 12 : 12 h photocycle at 27 ± 1 °C and 65 ± 5% relative humidity with a fresh diet) to terminate the diapause and observations are made on percentage pupation, pupal duration and weight, adult reproductive performance and population growth parameters. We find that the diapause in C. partellus significantly reduces the percentage pupation and weights of pupae, ultimately lowering the weight and reproductive performance of adults. Reduced weights of adult females are found to be directly associated with a lower number of egg cells in ovaries. Nevertheless, the reproductive performance of C. partellus males is also found to be greatly affected in the diapause (hibernation and aestivation) experiencing population in terms of the deposition of a lower number of spermatophores and eupyrene sperm in the reproductive tracts of females compared with the nondiapausing population. The results of the present study clearly indicate that a reduction in longevity, fecundity and egg viability, as well as a reduced rate of deposition of spermatophores and eupyrene sperm, in a diapause experiencing population of C. partellus ultimately leads to a reduction in population growth parameters, thus having implications for bio‐ecology and population dynamics under a changing climatic scenario.

Factors responsible for estivation in spotted stem borer, Chilo partellus (Swinhoe)

“…Rate of temperature change influences the physiological response, leading to change in morphological traits such as larval weight, length and head capsule width in C. partellus (Dhillon & Hasan, 2017b, ; Dhillon et al, ; Tamiru, Getu, Jembere, & Bruce, ). During present studies, these morphological traits were found significantly lower in diapausing than the nondiapausing larvae across test temperature and photoperiod conditions, which could be because of reduced feeding, energy loss due to construction of diapause chamber and reduction in body water content (Scheltes, ).…”

Special Significance of Non-Drosophila Insects in Aging

“…Noteworthy, diapause not only slows aging during diapause phase, but also has species-dependent effects on adult longevity after diapause. For example, maize stalk borer ( Busseola fusca ) and spotted stem borer ( Chilo partellus ) have shortened adult lifespans after diapause ( Gebre-Amlak, 1989 ; Dhillon and Hasan, 2018 ), but cotton bollworm ( H. armigera ) and multivoltine bruchid ( Kytorhinus sharpianus ) display extended lifespans after diapause ( Ishihara and Shimada, 1995 ; Chen et al, 2014 ).…”

Biological and biochemical diversity in different biotypes of spotted stem borer, Chilo partellus (Swinhoe) in India

“…There is a wide physiological and behavioural variation in C. partellus populations in terms of diapause (hibernation in northern India and aestivation in southern India) 7 , 9 . The nature and intensity of diapause exercises a profound effect on post-diapause development and reproduction 10 , while the mating behaviour influences reproduction and population build-up of C. partellus 11 . Mating between adults from diapausing and nondiapausing C. partellus populations from different geographical regions also results in genetic polymorphism 12 , which will have implications to breed for resistance, and develop strategies for the management of this pest.…”