Effect of temperature and photoperiod on growth and reproduction of Helix aspersa var. maxima

Abstract

Growth and reproduction of the snail Helix aspersa (Müller) var. maxima were examined at four combinations of temperature and artificial photoperiod and in transparent and opaque containers at two temperatures for over 40 weeks. Effects of temperature on both processes predominated. However, following 10 weeks of oviposition at optimum temperature (20°C), absence of photoperiod inhibited egg-laying throughout a further 15 weeks. Following inhibition of oviposition, the albumen gland atrophied, indicating the storage of secretory products.Snail growth was improved by rearing in opaque rather than transparent containers in a long-day photoperiod. Snail oviposition was unaffected by container type throughout a 28-week period, demonstrating an acute perception of photoperiodicity by snails maintained at low light intensity.