OutdoorNebraska

The Crayfish of Nebraska

Access digital copies of guides and regulations publications from the Nebraska Game and Parks Commission.

Issue link: http://digital.outdoornebraska.gov/i/720963

Contents of this Issue

Navigation

Page 24 of 148

16 abdomen. The ends of the fifth legs are fitted with picks, hairs and comb-like spines that help in the cleaning process. The second and third legs have miniature claws that also help pluck off debris. 7, 8, 9 Actual egg-laying occurs at night. The female raises up and waves her pleopods back and forth as they became covered with glair. Glair is produced by glands (see photo at right) under the telson and at the bases of the pleopods which, when mature, they take on a milky, white appearance. [The dictionary definition of "glair" is "a viscous substance resembling egg white".] After a bit the female rolled over on her back and curled her abdomen. The glair filled the space from the telson to the second legs. Into this area, the eggs were extruded from the oviduct openings at the bases of the third legs at the rate of 12 to 60 per minute. Apparently, at this same time, sperm was released from the seminal receptacle. The sperm and eggs mixed within the protection of the glair. With the abdomen still flexed and the fertilized eggs protected by the glair, the female began a series of rolling movements from left to right and back numerous times. In one example this process took over four hours. In the process, each egg is encased in a membrane that is connected to a pleopod with a fiber or string that must be formed from the glair. Eventually, the female stands up and, with flexing, the excess glair is washes away. 7, 8, 9 The female will now retreat to a secluded area while the eggs are developing. Most of the time the abdomen is curled under, protecting the eggs. Occasionally, the abdomen is straightened and the masses of eggs, hanging down like grapes, are waved back and forth to aerate them. The small, clawed legs are used to clean the eggs at this time. 7, 8, 9 The eggs will begin hatching in five to eight weeks. First, the egg case splits along the embryo's back. The embryo backs out of the egg case, feet last, over a period of about 20 minutes. At this time, the embryo is still attached to the inside of the case at the end of its tail. After straightening its legs, its large claws grab hold of the egg case stalk. It now keeps a firm grasp upon the stalk until its abdomen comes free of the case. This is the first stage and it is now about 4 mm long. About 48 hours later, it molts into a second stage larva. 7, 8, 9 I quote Andrews 7 who said, "As the shed skin still has its claws fast locked to the in the egg stalk the larva though it has drawn Glair glands on mature female Eggs attached to female's abdomen

Articles in this issue

view archives of OutdoorNebraska - The Crayfish of Nebraska