The annual reproductive cycle of the snail Megalobulimus abbreviatus (Bequaert, 1948) (Gastropoda, Pulmonata)

Abstract

Morphological changes in the sexual organs of the pulmonates were observed throughout a year and correlated with reproductive-cycle periods. Reproductive-organ weights of the snail Megalobulimus abbreviatus were recorded seasonally and gonad sections were analyzed morphologically. The weights were used to obtain the organosomatic index. Mean oocytic diameter and oocytic maturation index were based on gonad sections. It was concluded that M. abbreviatus is an iteroparous snail whose annual reproductive cycle is characterized by mating and egg laying throughout spring and early summer, and also by reproductive system preparation, occurring over the remainder of the summer until the end of winter, for a new breeding season.

Population dynamics of Megalobulimus paranaguensis (Gastropoda: Pulmonata) in the southeast coast of Brazil

“…This same pattern has been found in Megalobulimus abbreviatus (Bequaert, 1948) (HORN et al 2005). Iteroparity (more than one breeding season) is relatively common among pulmonate mollusks (CALOW 1978, (Fig.…”

“…The latter has several areas with lower plant density and household waste in its interior; and 3) young individuals were not marked in this study. In general, the newer cohort studies have the highest mortality rate (HELLER 2001) and the exclusion of juveniles tends to overestimate the calculated survival. This has been confirmed by ROMERO (2004), who documented a mortality rate higher than 94% in some years in a cohort of Megalobulimus mogianensis Simone & Leme, 1998.…”

Ultrastructural analysis of the dorsal body gland of the terrestrial snail Megalobulimus abbreviatus (Becquaert, 1948)

“…This period coincides with the initiation of the reproductive phase of these animals (Horn et al, 2005). These typical characteristics of M. abbreviatus DB, such as its large size, the fact that it is a single organ with a dense aspect, its close contact with three different ganglia of the central nervous system, encourage further investigation of the ultrastructural aspects of this gland and its relationship with neural structures.…”

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

“…During the day, or during dormancy periods, individuals bury themselves in the soil or leaf litter (Bequaert, 1948). They are iteroparous hermaphrodite snails with annual periodicity and great longevity, can live up to 35 years (Pinto-de-Oliveira et al, 1984;Horn et al, 2005;Fontenelle & Miranda, 2012), and generally occur in low densities and irregular distribution (Simone, 1999;Eston et al, 2006;. Like other Brazilian pulmonates, they have low reproductive potential, spawning 2-5 eggs per batch (Sobreira & Molina, 2002).…”

“…On the other hand, data about the reproductive biology of Megalobulimus species are still scarce, and restricted to the studies of Pinto- deOliveira et al (1984), on Megalobulimus bronni (Pfeiffer, 1847), Sobreira & Molina (2002), on Megalobulimus aff. gummatus (Hidalgo, 1870) and Horn et al (2005), on Megalobulimus abbreviatus (Bequaert, 1948). Information obtained by these studies have increased our knowledge of their ecology and can be used to develop conservation and management plans for Megalobulimus spp.…”