For many connoisseurs, cancer is a favorite delicacy that never gets boring. It has a unique taste and great nutritional value. There are different types of these arthropods, and each is a little different from the others. However, the main differences between the female and the male remain the same. In small crustaceans, external sexual characteristics are poorly expressed, so select several large individuals for inspection.
It is necessary
- - several large crayfish for comparison;
- - information about the characteristics of arthropod species.
Instructions
Step 1
Consider the body shape of an adult crayfish in the carapace-up position. As a rule, sexually mature (that is, three to four years old) males differ from their peers in more impressive size. In particular, they have large pincers - in aggressive males, this is a powerful weapon of defense and attack. The cephalothorax of male crayfish is also quite large; then their body begins to taper gradually and ends in a narrow tail (or "neck").
Step 2
Try to identify cancer by some external signs. An adult "woman" should have small claws and a cephalothorax, while she has a rather wide (barrel-shaped) tail - it is designed to serve as protection for developing eggs.
Step 3
Flip the arthropod upside down with its belly and carefully examine its legs. In males, you can observe an additional anterior pair of abdominal legs ("pseudopods") - they resemble tubes directed forward to the cephalothorax. The copulative organ - gonopodia - is formed from them. In females, these limbs are usually underdeveloped, and in some arthropods from the crustacean family, they are generally absent.
Step 4
There is a genital opening near the fifth pair of limbs of the male crayfish; in females, it is located at the base of the third pair of legs.
Step 5
In September, you can find greatly enlarged vas deferens in a male arthropod - they look like thick white curly tubes. If light slimy veins stretch across the tail, then you have a sexually mature female, ready to spawn.
Step 6
In the period from October to November in crayfish living in central Russia, the breeding period is usually in full swing. Under the "neck" of a fertilized female, future crustaceans adhering to the veins can appear (and develop until May-June). At this time, you can buy valuable live goods from sellers - a female crayfish with a "neck" filled with delicious caviar.
