We tested the effect of social isolation on the aggressiveness of an Amazonian fish: Astronotus ocellatus. Ten juvenile fishes were transferred from a group aquarium (60 x 60 x 40 cm) containing 15 individuals (without distinguishing sex) to an isolation aquarium (50 x 40 x 40 cm). Aggressiveness was tested by means of attacks on and displays toward the mirror image. The behavior was video-reco...

RNA:DNA ratios in individual red drum (Sciaenops ocellatus) were measured in laboratory-reared larvae and juveniles (6-20 mm standard length; age 16-40 days) to assess the effects of growth, starvation, and die1 periodicity on biochemical condition. RNA: DNA ratios were correlated positively with both absolute (mm day-') and instantaneous (% day-') growth rates. The effect of starvation was eva...

The neotropical cichlid genus Astronotus currently comprises two valid species: A. ocellatus Agassiz, 1831 and A. crassipinnis Heckel, 1840. The diagnosis is based on color pattern and meristics counts. However, body color pattern is highly variable between regions and the meristic counts show a considerable overlap between populations differing in color patterning. They do not represent true s...

Abstract Marine invertebrates serve as rich sources of secondary metabolites with intriguing chemical diversities and a wide spectrum biological activities. Particularly, marine shell-less sacoglossan mollusks have attracted much attentions due to the fact that apply complex defense agents against their predators. With purpose discovering bioactive develop marine-derived medicines from South Ch...

The molecular mechanisms underlying phenotypic plasticity are not well understood. Identifying mechanisms underlying alternative reproductive tactics (ARTs) in species for which the behavioural and fitness consequences of this variation are well characterized provides an opportunity to integrate evolutionary and mechanistic understanding of the maintenance of variation within populations. In th...

Sacoglossan sea slugs are unique in the animal kingdom in that they sequester and maintain active plastids that they acquire from the siphonaceous algae upon which they feed, making the animals photosynthetic. Although most sacoglossan species digest their freshly ingested plastids within hours, four species from the family Plakobranchidae retain their stolen plastids (kleptoplasts) in a photos...

BACKGROUND Snake venom is a potentially lethal and complex mixture of hundreds of functionally diverse proteins that are difficult to purify and hence difficult to characterize. These difficulties have inhibited the development of toxin-targeted therapy, and conventional antivenom is still generated from the sera of horses or sheep immunized with whole venom. Although life-saving, antivenoms co...