Efeito do sexo, dieta e tamanho de sementes sobre o tempo de retenção em Guariba preto cativo

Abstract

The effectiveness of a seed disperser depends on the time in which the seeds are retained in their digestive tract and involves several factors such as characteristics of the animals (physiology, morphology, health, age, sex, diet, body mass) and characteristics of the seeds (size , weight and rigidity). These are still largely unknown parameters for A. caraya. In this study we tested the influence of sex, diet, and seed size on the seed retention time (RT) in the digestive tract of howler monkeys using analysis of variance (ANOVA) for repeated-measurements. We used six captive individuals of Alouatta caraya (three of each sex), six seed species (two small, two medium, and two large), and three types of diet (composed of 15, 30, and 60% of leaves). The General Retention Time Mean (RTM) was 1.152 ± 639 min (range: 315-2.050 min) and the General Standard Deviation of the Retention Time (SDRT) was 577 ± 166 (range: 158-1.039 min). Significant influence was observed between the type of diet and the interaction between seed size and diet on RTM. RT was higher for diets comprised of 30% leaf and this effect varied for males and females dependent on seed size, which indicates that diet is an important factor in determining the effectiveness of the species as a seed disperser.