Asynchronous Hatching and Extended Parental Care in Aegla schmitti (Decapoda, Anomura)

ABSTRACT The aim of this study was to describe the behavior of newly-hatched juveniles and maternal care in Aegla schmitti. The experiment was conducted using seven ovigerous females with eggs at different stages of embryonic development and 12 eggs that had been placed in a separate aquarium. We observed asynchronous hatching in all females, with a mean of 66 hatched juveniles per female. The females also exhibited extended maternal care, allowing the juveniles to remain inside their abdominal chamber or on other parts of their body in the first few days after hatching. The juveniles that hatched in a separate aquarium fed on the remaining eggs, despite food being available. The incubation period and number of hatched eggs are highly variable between species with direct development, with no clear pattern being evident. However, asynchrony in hatching time is apparently common among freshwater anomurans, most likely due to the environmental conditions in which they live. Parental care is an important trait for crustaceans that live in osmotically unfavorable environments, such as freshwater, increasing the survival rate of juveniles.

Comparison of different methodologies for DNA extraction from Aegla longirostri

The aim of this study was to compare some DNA extraction methodologies for Aegla longirostri. The protocols were based on the traditional phenol-chloroform DNA extraction methodology and using a commercial kit for DNA extraction. They differed in tissues used, the addition - or not - of beta-mercaptoethanol to the lysis buffer, times and methods for the animal's conservation (frozen, in ethanol or fresh). Individuals stored at -20°C for a long time supplied lower molecular weight DNA than those stored for a short time. The best yield for the specimens preserved in ethanol was obtained for 15 days storage in 95 percent ethanol. The kit resulted in a low quantity of high molecular weight DNA. The best protocol for DNA extraction from Aeglidae, and probably for other crustaceans should, therefore, utilize fresh specimens, with addition of beta-mercaptoethanol to the lysis buffer.

Marcadores moleculares são ferramentas úteis para esclarecer dúvidas a respeito dos Aeglidae, único grupo de crustáceos Anomura de água doce. Essas técnicas dependem da obtenção de DNA de boa qualidade e sem contaminantes. O objetivo deste estudo foi comparar algumas metodologias de extração de DNA de Aegla longirostri. Quatorze protocolos foram analisados, baseados na metodologia tradicional de extração de DNA com fenol-clorofórmio, exceto o protocolo K no qual se utilizou um Kit. Os procedimentos diferiram quanto aos tecidos utilizados e a adição de beta-mercaptoetanol ao tampão de lise. Avaliaram-se também diferentes tempos e maneiras de conservação. Indivíduos congelados apresentaram maior degradação do material obtido conforme o tempo em que ficaram congelados. Para os indivíduos conservados em álcool, aqueles mantidos em etanol 95 por cento forneceram material de melhor qualidade. A utilização do Mini Kit resultou em uma quantidade muito pequena de DNA de alto peso molecular. O melhor protocolo para extração de DNA de Aeglidae utilizou músculos e brânquias, de indivíduos frescos com adição de beta-mercaptoetanol ao tampão de lise.