Mulberry silkworm

Types

Mulberry silk moths can be divided into three major categories based on seasonal brood frequency. Univoltine silk moths produce only one brood a season, and they are generally found in and around Europe. Univoltine eggs must hibernate through the winter, ultimately cross-fertilizing in spring. Bivoltine varieties are normally found in East Asia, and their accelerated breeding process is made possible by warmer climates. In addition, there are polyvoltine silk moths found only in the tropics. Their eggs typically hatch within 9 to 12 days, meaning there can be up to eight generations of larvae throughout the year. Mulberry silkworms are highly sensitive to environmental variables, and diapause - a physiological arrest in development - can be significantly influenced by photoperiod, temperature and humidity. Recent studies have reported the occurrence of non-diapause eggs in bivoltine races, indicating a more flexible diapause expression than previously understood.