Fernanda Keley Silva Pereira Navarro

Experimental assessment of temperature increase and presence of predator carcass changing the response of invertebrate shredders

The role of the invertebrate shredders in leaf decomposition process in tropical lotic ecosystems has been explored only recently. In addition to the influence of the quality of litter and the temperature, the risk of predation generally results in changes on the survival and behavior of invertebrate shredders. The aim of this study was to observe the responses of the invertebrate shredders to different species of leaf litters (Experiment 1: Talauma ovata and Inga laurina ; Experiment 2: Talauma ovata, Inga laurina and Richeria grandis ) under gradual temperature rise (24 °C, 26 °C, 28 °C, 30 °C, 32 °C), in the presence (Experiment 2) and absence (Experiment1) of fish (Astyanax sp.) carcasses, as well as to observe the possible consequences of the leaf mass loss (LML). The results from the first experiment suggest that the quality of the litter was capable of changing the feeding preference of the invertebrate shredders, regardless of temperature. In the second experiment, the leaf mass loss was faster in litter with higher quality (Talauma ovate and Richeria grandis ); in addition, we observed that the exploration of these resources resulted in the case-building in the presence of fish carcass. The negative correlation of leaf mass loss of Inga laurina in relation to temperature in the presence of fish carcass probably occurred due to an accelerated metabolic, respiratory and cardiac rates. Apparently, this process may have led to an increased shredding activity on the litters of better quality in relation to the Inga laurina. This fact may be related to less energy consumption, so as to meet their energy demands more efficiently.

Effect of photoperiod stress assessment and locomotor activity of female lambari (Astyanax bimaculatu)

Some studies and scientific investments have been done in aquaculture aiming to minimize the stress of the fish due to different factors, as management, nutritional status, water quality, temperature, photoperiod, and salinity. This study aimed to verify the effect of photoperiod on locomotor activity and plasma levels of cortisol and glucose in female Lambari. One hundred and twenty female Lambari adult were maintained in aquaria of 20 liters each in a completely randomized design with three treatments (T1 = 0Light: 24Dark, T2 = 12L: 12D, T3 = 24L: 0D) and four replications. The daily locomotor activity was registered during 15 days using an infrared photocell. After 40 days of experiment and previous fasting for 24 hours, fish were euthanized by a lethal dose of benzocaine. Female Lambari featured a diurnal rhythm of locomotor activity. Lambari subjected to 12:12 and LD photoperiod presented higher cortisol (12L:12E: 190.00 ± 37.73 ng/mL e 24L:0E: 148.850 ± 32.77 ng/mL) and locomotor activity levels and also lower survival rates (30.0 ± 7.07%) when compared to the LD photoperiod (cortisol: 85.570 ± 7.99 ng/mL, survival rates: 72.5 ± 4.330%). The glucose concentration (32.167 ± 22.73 mg/dL) and the growth (7.050 ±0.59cm) of fish subjected to LD photoperiod was significantly lower than in the other treatments. We conclude that light plays an important role in the growth, behavior and welfare of female Lambari. Besides, our data highlighted that fish submitted to a long light period present a more stressed and more aggressive status when compared to fish submitted to a continuous darkness.

Leaf litter input and electrical conductivity may change density of Phylloicus sp. (Trichoptera: Calamoceratidae) in a Brazilian savannah stream

Objetivo Invertebrados fragmentadores sao geralmente escassos em riachos tropicais, com evidencias consideraveis sugerindo que a disponibilidade de recursos alimentares possa determinar esse padrao em riachos de cabeceira. O objetivo desse estudo foi avaliar os efeitos de variacoes na disponibilidade de recursos alimentares durante um ano na densidade Phylloicus sp. (Trichoptera: Calamoceratidae), o qual esta entre os principais invertebrados fragmentadores em riachos de cabeceira neotropicais. Metodos Medimos a importância relativa da materia orgânica vegetal aloctone em termos de entrada vertical (EV) e estoque bentico (EB) na densidade de Phylloicus sp., entre outubro de 2012 e setembro de 2013, em um riacho preservado de terceira ordem no Cerrado, Distrito Federal, Brasil. Resultados Folhas foi a fracao mais abundante na EV e EB (~70%). A biomassa de folhas foi alta durante todo o ano (biomassa mensal de 24,2 g.m–2 ±23,1 SD na EV e 46,1 g.m–2 ±76,7 SD no EB), aumentando ao final da estacao seca (agosto a outubro). Phylloicus sp. Teve baixa densidade durante o ano (2,4 ± 4,9 ind.m–2 media±DP) e seu pico foi associado a maior biomassa de folhas na EV e maior condutividade eletrica no riacho. O pico bem definido de Phylloicus sp. em outubro sugere uma interacao entre o aumento densidade de Phylloicus sp. e a entrada de folhas no final da estacao seca. A condutividade eletrica tambem foi maior em outubro, refletindo um aumento nas concentracoes de nutrientes na agua durante esse periodo. Conclusoes A disponibilidade de detritos foliares pode ser um fator determinante para a densidade sazonal de Phylloicus sp., sugerindo um efeito bottom-up em riachos tropicais. Mudancas no suprimento de recursos aloctones em riachos podem afetar as populacoes de fragmentadores como Phylloicus sp. e influencias antropogenicas na vegetacao riparia podem afetar processos ecologicos de grande importância para riachos de cabeceira.

Interação com os pais e o uso do espaço por um infante de Alouatta fusca (Geoffroy Saint-Hilaire, 1812) em cativeiro

Primates are social animals that have bond between mother and offspring, unlike other orders of mammals. The survival of an infant primate is completely dependent on the care provided by members of their social group, particularly maternal care. The aim of this study was to analyze the use of premises for an infant of monkey and its proximity to the parents. The group of monkeys was composed of a pair of adult female and her pup at 4 months of age. The observation period was from august to december 2006, making an average of 96 hours of sampling effort. The method of observation was the focal animal with instant record, with 30 second intervals for 1 hour per day. The study site was an exhibition space of the Zoo-Botanical Foundation of Belo Horizonte, 7 m high, 6 m wide, 7 m deep with the presence of internal landscaping. The results revealed greater contact with the infants mother and father in relation to a significant departure (P < 0.05) compared to the puppys maternal contact with increasing age and greater independence. The most used during the first 3 months of captivity was the pergola. In December, a period of higher rainfall, the chick ventral increased interactions with the mother, and stayed longer in the barrel. Information obtained here will contribute to a better understanding in relation to infants of Alouatta fusca, their social interactions and use of space that can be used to improve the ex-situ management of animals, creating better conditions for the stay of those in captivity, using appropriate structures that mimic the natural environment, to ensure the welfare of apes and thus the survival of the species.

IMPORTANCE OF VITAMIN C ON GROWTH AND GONADAL DEVELOPMENT IN FISH

RESUMO: O crescimento saudável dos peixes bem como, a melhora nos índices reprodutivos, é alcançado com o balanceamento de dietas em função da exigência nutricional em cada fase de desenvolvimento. A vitamina C atua em diversos processos fisiológicos no peixe, sendo, portanto, de suma importância o conhecimento dos seus efeitos no organismo do animal. O presente trabalho aborda os efeitos da vitamina C no crescimento e no desenvolvimento gonadal dos peixes.