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

• Published in: Physiological entomology 2018-09, Vol.43 (3), p.196-206
• Main Authors: Dhillon, Mukesh K., Hasan, Fazil
• Format: Article
• Language: English
• Subjects: Adults; Aestivation; Chilo partellus; Climate change; Deposition; Diapause; diapause development; Duration; Dynamics; egg viability; eupyrene sperm; Fecundity; Females; Hibernation; Larvae; longevity; Males; Ova; Ovaries; Parameters; Physiology; Population dynamics; Population growth; Pupae; Pupation; Relative humidity; Reproduction; Sperm; Spermatophores; Spermatozoa; Viability; Weight; Weight reduction
• ISSN: 0307-6962; 1365-3032
• DOI: 10.1111/phen.12243

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. Diapause in Chilo partellus significantly reduces the percentage pupation and weights of pupae, leading to adults with a lower weight and lower reproductive performance. Chilo partellus males from a diapause experiencing population deposite a significantly lower number of spermatophores and eupyrene sperm in the reproductive tracts of females compared with the nondiapausing population. There is a significant reduction in longevity, fecundity, number of egg cells in ovaries and egg viability in a diapausing population compared with a nondiapausing population of C. partellus.