page_title: Colochirus robustus
section_title: Behavior and reproduction
hierarchical_section_title: Colochirus robustus / Behavior and reproduction
caption_attribution_description: English: Robust sea cucumbers (Colochirus robustus) on reef, Bali, Indonesia.
context_page_description: Colochirus robustus, commonly known as the robust sea cucumber or the yellow sea cucumber, is a species of sea cucumber in the family Cucumariidae. It is found in shallow seas in tropical parts of the central Indo-Pacific region. C. robustus belongs to the class Holothuroidea, a group of echinoderms called sea cucumbers and known for unusual behavior including evisceration, asexual reproduction, and regeneration. The robust sea cucumber has a soft body and lacks a spine, but it does have an endoskeleton consisting of microscopic spicules, or ossicles, made of calcium carbonate. C. robustus has a respiratory tree that allows it to extract oxygen for respiration, using the anus to pump water. The robust sea cucumber is an important dietary staple for many East and Southeast Asian populations, and has been used for medicinal purposes for hundreds of years. Recent research suggests that peptides from C. robustus enhance the activity of the immune system.
context_section_description: Colochirus robustus is usually found on rocks and reefs in places with moderate to rapid water flow. It clings to the substrate with its tube feet, spreading its feathery tentacles to catch zooplankton and other organic particles as they float past. The tentacles are then retracted to the mouth where the food particles are scraped off.
  Some Holothurians may reproduce asexually by fission. It was reported that C. robustus was capable of fission, but there was no evidence of asexual reproduction in natural populations. When placed in a tank under poor environmental conditions, however, asexual reproduction by fission was observed in C. robustus. It is likely asexual reproduction was not found in natural populations because the conditions were not stressful enough. Therefore, Colochirus robustus can reproduce both sexually and asexually. In the latter case, fission can take place with a transverse crack developing halfway along the body and gradually widening until the two halves split apart. The posterior end then grows a new anus while the anterior end develops a mouth and new tentacles.
  Echinoderms are capable of restoring lost body parts, a skill utilized by Holothurians in several ways. Many Holothurians, including C. robustus, are capable of regeneration when transected. A 2012 study of Holothurians in Nha Trang Bay first found that when C. robustus was cut in half, both its posterior and anterior ends could survive. To regenerate its digestive organ in the anterior end, the gut atrophies up to the esophagus, and new gut develops from there. In the posterior end, the gut does not atrophy but becomes thinner and grows forward. Most Dendrochirotids have not been found to be capable of regeneration of both ends when transected. Usually only the anterior end can survive; however, C. robustus is an exception.
  In order to escape predators, some Holothurians are capable of evisceration: a process in which the gut and other internal organs are suddenly expelled through the mouth or anus. When injected with potassium chloride, many of the species of holothurians will perform evisceration, but potassium chloride has been shown to fail to induce evisceration in C. robustus. Evisceration was observed, however, when C. robustus was placed in a tank under poor environmental conditions. Like asexual reproduction, evisceration in C. robustus is thought to be brought on by stressful conditions
caption: A group of robust sea cucumbers on a reef in Bali, Indonesia
exif: {"Image Make": "Canon", "Image Model": "Canon DIGITAL IXUS 800 IS", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop 7.0", "Image DateTime": "2006:12:02 21:15:00", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "224", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1066", "Thumbnail JPEGInterchangeFormatLength": "6498", "EXIF ExposureTime": "1/60", "EXIF FNumber": "28/5", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2006:11:21 11:37:51", "EXIF DateTimeDigitized": "2006:11:21 11:37:51", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "189/32", "EXIF ApertureValue": "159/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "95/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash fired, auto mode", "EXIF FocalLength": "29/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "640", "EXIF ExifImageLength": "480", "EXIF FocalPlaneXResolution": "112640/9", "EXIF FocalPlaneYResolution": "2112000/169", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}