Life cycle traits, secondary production and DNA barcode of Oxyurella ciliata Bergamin, 1939 (Crustacea, Branchiopoda, Anomopoda, Chydoridae)

Abstract

This study the life cycle and quantify the secondary production of the cladoceran Oxyurella ciliata under controlled conditions in a laboratory and use molecular biology as a tool to investigate its genetic characteristics. The organisms were collected from Baia do Gerente, a pond from the Pantanal region, MS state, Brazil. They were acclimatized, maintained at a controlled temperature (25 ± 1 °C) and photoperiod (12/12h light-dark), fed with the microalgae Raphidocelis subcapitata and observed daily to obtain the data. O. ciliata had a high total egg production of 34.18 ± 9.68 eggs/female and an average longevity of 58.50 ± 16.30 days. These values differed from those previously reported for O. longicaudis, another congeneric species. There was an exponential growth of biomass until instar 6 and the largest secondary production was from the young to the adult phase, which corresponds to the beginning of the reproductive phase. The molecular data revealed that the genetic divergence between the sequence of O. ciliata and that of O. longicaudis is approximately 18 %, which seems high considering that both belong to the same genus. Comparing life cycle data and DNA Barcode, Oxyurella ciliata and O. longicaudis are very distant and have distinct morphological and biological characteristics, such as: body size, egg size, growth, fertility, longevity and development times. This study highlights the importance of molecular studies and information on the life cycle of neotropical cladocerans, in an integrated way, to have a better taxonomic and ecological interpretation of the species.