Frugivoria por duas espécies de Brycon da Bacia Amazônica

Abstract

The Brycon genus, belonging to the Characidae family, is represented by medium to large animals, of migratory, omnivorous and gregarious habit. The Silver River Basin is distributed from Mexico. Studies show the importance of some species of the genus in the dispersion of riparian plants. The present study aimed to evaluate the percentage (PG), germination speed index (IVG) and average germination time (TMG) of the Ficus cf. gomelleira (Moraceae) submitted to the gastrointestinal tract of the frugivorous Characiforme Brycon falcatus. The study is divided into three chapters. Chapter 1 consists of a study of the germinative characteristics of F. cf. gomelleira submitted to passage through the gastrointestinal tract of B. falcatus, where experiment used 30 fish with size between 9.5 to 29.0 cm, the animals being individualized and fed with 100 seeds of F.cf. gomelleira, later were collected from the feces and submitted to germination. Each fish was subjected to three repetitions. In the control treatment, the germination of 100 F. cf. gomelleira obtained directly from the mother plant (30 repetitions). For the analysis of the treatment means, the Tukey test was applied, at the level of 5% probability. The seeds submitted to passage through the gastrointestinal tract showed PG = 81.4%, IVG = 39.29 and TMG = 90 days, and the control treatment showed PG: 61.47%, IVG = 17 and TMG = 120. The higher values of PG, IVG and lower TMG in relation to the control treatment, indicated that the passage through the gastrointestinal tract increases the germination potential, certainly by the removal of inhibitory factors of germination, indicating B. falcatus as a potential disperser of the fig tree. Chapter 2 consists of a description of the predation of Mabea fistulifera seeds by Brycon cephalus, in captivity. The behavior was observed in eight individuals with sizes between 11, 6 to 32.0 cm, individualized in 61 L aquariums, in a water recirculation system, receiving a diet composed of commercial food and M. fistulifera seeds supplied ad libitum . The number of seeds ingested, the time for regurgitation of the first and the last ingested seed and the time of oral handling of the seeds were observed. The observations indicated B. cephalus as a predator of Mabea fistulifera. Chapter 3 describes evidence of allocoprophagy in the Teles Pires river involving the characids Brycon falcatus and Leporinus friderici with feces of Hydrochoerus hydrochaeris and describes the random record of B. cephalus autocoprophagy in captivity. The appendix, is a botanical description of woody vegetation, with ichthychloric potential of the Center-North portion of the Teles Pires river basin (MT). The species were classified according to dispersion syndromes and fruits as to dry and fleshy. The botanical survey was carried out, with quarterly collections from January 2017 to July 2018. The arboreal strata stood out with 64% of the records, being dispersed marjoritly by zoocory (87%). The verified patterns indicate that the Center-North region of the Teles Pires River constitutes an ecosystem of high richness of plant species with food potential for fish.