Some Biological Aspects of Bloodworm: Chironomus pallidinubeculosus Tokunaga, 1964 (Diptera: Chironomidae) (early view)

Abstract

Some biological aspects of local bloodworms in Thailand were investigated. In this study, the larvae of one species of bloodworm, identified as Chironomus pallidinubeculosus Tokunaga 1936, were reared in plastic containers at 25 °C and fed with fish feed solutions three days per week. The eggs sample were processed by histological and TEM techniques. Yield (g·m-2), moisture, ash, crude protein, crude lipid, crude fiber, and gross energy (KJ·g-1) were determined in reared larvae. The results showed that C. pallidinubeculosus larvae could survive and be bred in plastic containers, controlled laboratory conditions, and have four instars. The suitable physico-chemical parameters during rearing were low to moderate dissolved oxygen (1.18-5.00 mg/L), electrical conductivity (462-714 ?S), and total dissolved solids (249-378 mg/L). Moreover, adults had a high average number of eggs per one egg mass from 193.2±49.99 to 331.86±80.23 and an average hatchability of 90.69% to 94.49% during the 1st to 3rd generations, respectively. The life cycle of this study was approximately 19-23 days. Polylecithal and centrolecithal eggs were observed. After gelatinous massremoval, the egg was covered by non-regularly exochorionic jelly. The internal morphology ofthe egg is mainly composed of proteid yolk, lipids, and dense granular. Larvae constituted89.78% water; they had a high 15th day yield (g?m-2), and the minimum area of larvae for massculture was 1.2 cm2. The proximate composition analysis in reared larvae showed that crudeprotein, crude lipid crude fiber, and gross energy were higher than its feed. The biology aspectstudy of the bloodworms found they were easy to culture; they should be considered a modelorganism for further ecology, nutrition, and toxicology studies.