Rotifers are widely distributed in lakes, ponds, rivers, coastal waters and other light and salty water bodies. Even moist soil and moss have their traces. Rotifers have extremely high reproduction rate and high yield, which is of great significance in the study of ecosystem structure, function and biological productivity. Rotifers are open bait for most economic aquatic animals. It has great application value in fishery production. Rotifer is also an indicator organism, which is widely used in environmental monitoring and ecotoxicological research.
Basic introduction of Chinese names: Latin scientific name of rotifer: rotifer alias: rotifer phylum: marsupial phylum: rotifer subclass: amphipoda: Youlong suborder: collembola suborder: collembola suborder, hirudina suborder, single-nest reproduction: characteristics, composition, classification, chewer type, living habits, lifestyle, hidden characteristics, and sexual reproduction. That is, the crown with ciliated ring. Rotifers on water lily leaves II. The pharynx of the digestive tract is particularly swollen, forming a chewing bag with developed masticatory muscles and nourishing bodies inside. That is, there are chewing bags containing chewing devices. 3. There are a pair of protorenal ducts on both sides of the body cavity, with flame rods at the ends. That is to say, there is a protorenal duct with a burning bulb at its end. In a word, the main characteristics of rotifers are crown, chewing sac and protorenal duct. The body of most rotifers consists of three parts: head, trunk and feet (some have no feet). The morphological structure of rotifers is shown in the right figure: classification-a rotifer type is divided into two symmetrical disks, each with a short handle, and the mouth is located between the two short handles in the center of the ventral surface. Most people with this crown are benthos. The rotifer-shaped mouth and perioral area are located on the ventral surface of the crown, and there is a circle of thick bristles (false wheel ring) on the crown. The perioral area of Tricyclic Rotifer is very narrow, with only one undeveloped cilia around the opening, and the cilia around the apex are developed, but they are discontinuous in the center of the dorsal surface and the ventral surface. The top area is quite wide. This area often has a prickly or rod-like sensory mechanism. This crown is typical of planktonic rotifers. The rotifer perizone forms two ciliated rings. The upper ring is called a wheel ring. The lower ring is called the waist ring. The mouth is located between the two. Adapt to the floating life. The periapical area of rotifer is horseshoe-shaped. The posterior pendulous orifice and perioral region are located here. Therefore, the oral cavity is located at the posterior side of the crown. Adapt to the floating life. The whole crown of rotifer has six rubber sheaths, which are funnel-shaped. The upper edge often forms several lobes (1, 3, 5, 7). There are bristles on it. The mouth is deeply immersed in the bottom of the funnel. This funnel is actually the perioral area, and the periapical area has disappeared, which is suitable for sessile growth. There are many long teeth in the four-mallet hook. The mallet handle is wide and short, divided into three sections, and the anvil is short and thick. The left and right anvil branches are triangular, and there are often fine teeth on the inside. Combined with rotifer crown, theropoda belongs to this category. Including floating, bottom layer and standing, it depends on the flowing vortex precipitation formed by the cilia movement of the head crown, and feeds on micro-organisms and young trees in the water. The five-mallet hook of rotifer rose is the most developed, with two semi-circular thin slices and many parallel edges, of which 2-3 (or some) edges are relatively thick, and the inner ends of the edges form arrow-shaped teeth; The anvil branches are small and triangular, and the anvil and mallet handle degenerate. The combination of dendritic chewer and rotifer crown is the main feature of leech. Suitable for sedimentation feeding. The six-hook anvil and mallet handle are extremely degraded, and the chopping block is wide and almost semicircular. The mallet hook is composed of several long teeth except for the auxiliary mallet hook to closely connect the chopping block and mallet hook. This rotifer shreds large organisms (such as cladocera and copepods) with mallet hooks. ) and broke into the trap. Suitable for ambush feeding. Most camps are fixed, and very few camps are floating. Rotifers with different types of chewers have different degrees of development and great morphological changes, forming different types of chewers. The common types of chewers are as follows: ① All chewing plates of hammer type are thick and firm, and the hammer hook is bent. The central part is divided into several long teeth and placed horizontally on the chopping block. Chew food continuously through the movement of the left and right mallet hooks. (2) The branched anvil and mallet handle have been highly degraded, the anvil has shrunk into triangular strips, and the left and right mallet hooks are the most developed, each of which is semi-circular thin, and the two halves are combined into a circle, each with many parallel ribs. (3) The mallet hook consists of many long teeth, and the mallet handle is short and wide, which is obviously divided into three sections. The anvil base is short and thick, and the left and right anvil branches are in the shape of Yangtze River Delta with fine teeth inside. Rotifers (④) have well-developed rhizomes with 1-2 spines inside. The anvil became shorter, the hammer handle degenerated leaving only traces, and the hammer hook became thinner. An entrance that can suddenly extend out of the exit to catch food. ⑤ Comb-shaped chopping block is violin-shaped, with complicated mallet handles and crescent-shaped bent branches in some parts. There is a front pharynx in front of the mallet handle, which is often more developed than the mallet hook. Sucking is the main food. ⑥ Both the rod anvil and the hammer handle are slender rods. The anvil branch is a wide triangle, and the mallet hook generally has 1-2 teeth. The mallet hook can stick out from the mouth, grab the food and crush it. Rotifers with this kind of chewer are a fierce species. ⑦ The pincer-shaped mallet handle is very long, and it is pincer-shaped when interlaced with the slender mallet hook. The base of the anvil is short, the branches of the anvil are long and slightly curved, and they are also pincer-shaped, with many serrations on the inside. When eating, the pincer-like chewer can completely extend out of the mouth to grab food. ⑧ Hook-shaped anvil and hammer handle have been highly degraded, the anvil is wide and developed, and the hammer hook system consists of a few long arrow-shaped teeth. Life characteristics 1, exercise Most rotifers mainly use the rotation or spiral movement of the cilia of the head cap, while other species with appendages, such as rotifer with three limbs, rotifer with many limbs and rotifer with giant wrist, use this to jump. Rotifer's tail is not the main motor organ. But its swing will undoubtedly play a role in fueling the flames. When the secretion of the foot gland sticks to the substrate, it will also move around the foot as the center. Rotifers with three limbs can't move their hind limbs. But it can act as a rudder in motion. No matter what kind of sports. Its speed is generally