Comportamento e ciclo de vida de Dysopeas muibum Marcus & Marcus, 1968 (Mollusca, Subulinidae) em laboratório: efeitos do isolamento e do fotoperíodo sobre padrões de crescimento, reprodução, mortalidade e conquiliomorfometria

Abstract

Knowledge of biological, morphological and behavioral characteristics of terrestrial molluscs is important for the development of pest control measures and strategies for the conservation of species. This study aimed to characterize the patterns of biology, conchiliomorphometric and behavior of the species Dysopeas muibum and check the effects of isolation and photoperiod on its life cycle and shell morphometry, under laboratory conditions. We conducted monitoring growth of the shell, release of puppies and mortality of 160 molluscs, of which 40 were kept isolated and 120 grouped (10 molluscs per group; 40 in natural conditions of temperature, relative humidity and photoperiod, and 80 with controlled conditions – 40 with long days and 40 with short days), from birth to 180 days of life, when the measures of the shell were taken. To check the schedule of activity and compose the ethogram, 30 adult molluscs (10 molluscs per group) were observed for 24 continuous hours, through the scanning method, with a record of behavioral acts at intervals of 20 minutes. For verifying the occurrence of aggregation and the preference for resting place, for five days, at 24 hour intervals, were observed in 30 adult molluscs (10 molluscs per group): number of aggregations, of aggregates and isolated individuals, and of individuals below the disc with food, below the disc without food, on the substrate, buried and in the wall of terrarium. For all analyzes, the molluscs were reared in plastic terrariums sealed with cotton fabric and elastic, containing plant soil sterile and moistened with tap water, and fed with food to broilers enriched with calcium carbonate. It was found that the species occurs in the Juiz de Fora City, MG, Brazil, has the soft yellowish and small and elongated shell, and is able to reproduce by self-fertilization. It has indeterminate growth, fecundity increases with body size, iteroparity and low mortality before and after sexual maturity, not having the photoperiod effect on these patterns. The controlled conditions of temperature, relative humidity and photoperiod favored growth, conchiliomorphometric values higher and fast reach sexual maturity, while the decrease in day length favored fecundity. The isolation increased the total number of pups, number of pups per parent mollusc and the interval between reproductive events, reduced the number of reproductive events and pups per event, and did not influence growth, reach sexual maturity, growth-reproduction relation, mortality and conchiliomorphometric. The ethogram was composed of eight behavioral acts: lie, lie buried, move, bury, explore, food, emerge and interact. The species had a greater tendency to rest and locomotion was the behavioral act prevalent activity, showed no activity time predominantly nocturnal and affiliative behavior, and their favorite place to rest was buried in substrate.