Biological Parameters of the Conical Snail Cochlicella acuta (MÜLLER, 1774) (Gastropoda: Cochlicellidae) under Laboratory Conditions

Abstract

Biological parameters like as mating, pre-oviposition, oviposition, post-oviposition, and generation periods as well as growth rate of the pointed or conical snail Cochlicella acuta (Muller, 1774) (Gastropoda: Cochlicellidae)were studied in the Plant Protection Department, Faculty of Agriculture, Zagazig University under laboratory conditions. In 2017/2018,samples of pointed or conical snails of date palm were collected during its reproductive and activity season from highly infested palm tree orchards at Abo-Nagii farm, El-Kassassein, Ismailia governorate. The temperature and RH% values ranged from 19 to 28oC and 48 to 61, respectively. Snails immediately transported back to the laboratory where they were identified to species and kept in 1000 cc boxes plastic with tight fitting perforated covers , provided with fresh lettuce leaves (Lactuca sativa) as a source of food reared and ovipostion site. Plastic containers were staked side by side with moist soil. The fresh lettuce leaves were checked daily and replaced with fresh one. The laboratory observations revealed that in spite of this species is hermaphrodite, the cross mating was essential for ovipostion as unmated ones did not lay any egg. Mating occurs when snail individuals reach their sexual maturity as calculated from adulthood until mating. Besides large adults produced more eggs than small ones over the whole breeding season; this period was 95 ± 28.4 days in average. Pre-oviposition period (from mating till laying first egg) lasted for an average of 17.3 ± 6.1 days. Oviposition period (from laying first egg till last one) averaged 84.3 ± 23.6 days during which snail individual deposited a total of 110 ± 59.5 eggs. Post-oviposition period (from last laid egg till mortality) was 140 ± 74.3 days. The generation period (from egg to egg) of this species extended to an average of 275.3 ± 32.1 day