Color Variations of Immature Nypa Worms in The Kapuas Estuary, West Kalimantan
Variasi Warna Pada Cacing Nipah yang Belum Matang Di Muara Kapuas, Kalimantan Barat.
Abstract
Nypa worm (Namalycastis rhodochorde) previously described to the new species, included in Namalycastis abiuma species group with had an unusual shape and had large body. Color variation in N. rhodochorde was obtained in mature. N. rhodochorde had normal color when life was bright pink, while mature were turned red (females) and green (males). But until now there was no report color variation in immature N. rhodochorde. This study had examined color variations of nypa worms in Kapuas Estuary, West Kalimantan. Photogrammetry is one of the methods used to study the variations in color. This method could be measure color through photos. Samples were photographed on spiral labyrinth glass to limit the movement of the worm and Strobist Macro Photo Studio for light stabilization. Digital images of nypa worm was recorded in RAW format then converted to 8-bit TIFF. Determination of the measured area is by selecting the whole dorsal body seen in TIFF files as ROI. Therefore the values of RGB colour spaces was converted to the corresponding values of CIE Lab colour space. Beside digital photogrammetry, color was described by the eye of author. Histological analysis was performed observed the anatomical difference between the color groups. This was due to morphological and anatomical changes occurring during maturation N. rhodochorde. Epidermal cells was observed due to contains of secretory cells that function as mucus secretion. Mucus plays an important role in the life of polychaeta. Epidermal preparation of nypa worm was done using paraffin method. Based on the analysis using photogrammetry, there is no significant difference between males and females colors. By eye, obtained color variations in immature worms categorized as bright pink, dark pink and brown. Most of the worms were bright pink and the least is brown. Bright pink worm was immature whereas dark pink worm was submature. These suggest that color variation related to gametogenesis. From histology of epidermis we obtained three forms of secretory cell within each group. Dark pink had more closed cell, it was suspected that cell more active so that more of mucus in cell. This was coused the nypa worm prepared to maturity. Different with brown worms that was immature had larger cells, it was suspected to be an adaptation to the environment. In this study was not found mature samples. It was suspected when sampling was not a of spawning time. Polychaeta spawning time is strongly influenced by the physical and biological environment conditions.