36 resultados para Dedekind, Richard 1831-1916
em Scielo Saúde Pública - SP
Resumo:
The effects of food concentration and temperature on embryonic and postem-bryonic duration of three tropical species, Daphnia gessneri(1.5mm), Diaphanosoma sarsi(1.2mm) and Moina reticulata(0.8mm), were investigated as part of life cycle studies which included growth, body size and reproduction. These are the very first experimental studies undertaken on these species. The long-term growth experiments were performed under controlled laboratory conditions at all combinations of temperature (22"C, 27"C and 32"C) and constant food concentration (0.03, 0.05, 0.10, 0.25, 0.50 and 1.00 mgC/L) of the unicellular green alga Scenedesmus acutus.Animals were examined twice daily throughout their life cycle from the neonate to third adult instar. In all three species, temperature exerted the most powerful influence on embryonic duration but there was also a smaller food effect. In D. gessneri,postembry-onic durations remained more or less the same at food levels 0.25 mgC/L but were influenced by temperature. At food concentrations of 0.1 mgC/L or lower, postembryonic durations became increasingly prolonged, particularly at high temperatures. This threshold concentration is affected by temperature: in D. gessneri,it was 0.1 mgC/L at 22oC and 27oC but higher at 32oC (between 0.25 and 0.50 mgC/L). At the same temperature of 27oC, the food threshold level varied between species: it was higher (0.25 mgC/L) for D. sarsiand lower (0.05 mgC/L) for M. reticulatacompared with D. gessneri(0.1 mgC/L). In both embryonic and postembryonic durations there is a body size effect as the absolute durations were longest in the largest species and shortest in the smallest species In all three species, prolongation of postembryonic duration at combinations of high temperature and lowered food levels was accompanied by increased number of juvenile instars.
Resumo:
A fêmea de Ergasilus coatiarussp. n. (Copepoda, Poecilostomatoida, Ergasilidae) é descrita dos filamentos branquiais de Cichla monoculusSpix, 1831, capturado na ilha da Marchantaria, próximo a Manaus, Brasil. A nova espécie difere das demais do gênero por apresentar apenas um segmento no exopódito da 4a perna e um espinho serrilhado na parte distal da articulação entre o 3º e 4º segmento da antena.
Contribuição ao conhecimento das espécies do gênero Notochaeta Aldrich, 1916 (Diptera-Sarcophagidae)
Resumo:
The author redescrlbes M. januarius (Navas), reared in laboratory, studying also the larvae. One species of Bombylidae belonging to a genus near Diplocampta emerged from two cocoons of the Neuroptera.
Resumo:
Durante a terceira excursão realizada pela Seção de Helmintologia do Instituto Oswaldo Cruz, à localidade de Arraial do Cabo, em Cabo Frio, Estado do Rio de Janeiro, em junho de 1963, tivemos a oportunidade de encontrar ao amanhecer do dia 22 um exemplar fêmea de Diomodea melanophris Temm. (Albatroz), pousado no chão, nas proximidades da praia, provàvelmente levado para lá pela forte ventania que ocorrera durante a noite. Ao necropsiarmos essa ave encontramos, localizados mo estômago, alguns nematódeos dos quais um macho e quatro fêmeas pertencentes ao gênero Seuratia Skrjabin, 1916 e devido à sua raridade nas costas brasileiras e ao achado dos parasitos, resolvemos efetuar o reestudo dêsses helmintos, descritos por Stossich, e rever o gênero proposto por Skrjabin.
Resumo:
Male and female of Punaphyto lopesi, a new species from Equador are described and illustrated.