Impact of Natural and Mechanical Mating on Fecundity and Egg Retention in Muga Silkworm, Antheraea assamensis (Lepidoptera: Saturniidae)

Abstract

Lepidopteran muga silkworm Antheraea assamensis belonging to Saturnidae is an economically important insect geographically endemic to Assam and the northeastern region of India. Like any other insect species, oviposition is one of the most vital aspects of A. assamensis as it allocates the majority of its energy during its lifecycle. Muga silkworm seed production technology has still not been studied much in detail. The demand for silkworm seeds rises during the commercial rearing season in the region, Central Silk Board has established seed production centres to cater for the demand of the sericulture industry. The number of seed cocoons processed for commercial seed production is 1.5-2.5 lakhs per annum. Muga silkworm emergence pattern is asynchronous, no. of male and female moths is not equal during operations. A. assamensis is nocturnal in habit, and emergence and coupling take place at night. Due to the asynchronous pattern of emergence, it is quite often that female moths run out of mates in the seed production centres. Due to the depleting number of potential male mates, the mating will be done mechanically by putting male female moths in a bamboo box to save the time and energy of silk moths. So, an experiment was conducted to study the difference in fecundity between naturally mated and mechanically mated muga silkworms and its impact on mating duration at Silkworm Seed Production Centre, Kaliabari, Boko, Assam during commercial crop (April-May & Oct-Nov) of 2023. The results of the study showed that maximum fecundity was observed in silkworms which are naturally mated with 214±12.08 eggs per female. Whereas, the mechanically mated muga silkworm females showed slightly less fecundity compared to naturally mated females with 203.2±12.77 eggs per female. The results on egg retention showed a clear difference with 18.6±4.77 and 16.6±8.64 eggs per female in natural and mechanical mating, respectively. The slightest reduction in fecundity and increased egg retention in female moths might be due to the impact of mechanical mating on mating duration which reported only 5.5±1.29 hrs, whereas natural mating facilitated a higher mating duration with 8.2±1.30hrs, respectively. This study showed the significance of mating type (natural and mechanical) and its impact on fecundity and egg retention of muga silkworm.