Aspects of biology of Megalobulimus paranaguensis (Gastropoda, Acavoidea) in the coastal plain of the Brazilian southeast

Aspectos da biologia de Megalobulimus paranaguensis (Gastropoda, Acavoidea) na planície costeira do sudeste brasileiro

ABSTRACT

We studied the reproductive biology of Megalobulimus paranaguensis (Pilsbry & Ihering, 1900), a large and long-lived land gastropod from the Atlantic Rainforest of Brazil. The study was conducted at an urban park in the city of Santos, state of São Paulo. For 4 years, we counted the egg postures and annual eclosion rate of 32 captive snails and looked for associations between egg posture and the climatical variables of the period. The annual mean posture of 8.7 eggs per snail obtained in our results is a small number, but typical of Brazilian macromollusks. The annual eclosion rate was 31%. The beginning of the annual activity period of snails occurred in the middle of March, and lasted 33.97±3.02 weeks. The dormancy period started in the beginning of November, and lasted 18.39±3.11 weeks. There were two egg posture peaks, a minor peak between March and May, and a major peak between August and November, with greater values in September. Megalobulimus paranaguensis has a well-defined seasonal reproductive pattern influenced by environmental temperature and temperature range. Furthermore, in this snail, reproduction is negatively influenced by temperature increasing and temperature range.

KEYWORDS
Aruá-do-mato; egg posture; land snail; Atlantic Rainforest; reproduction