One of the most feared animals in the world is the nasty scorpion. These are predatory species that belong to the class Arachnida. They are not your regular insects and critters. But, belong to the eight legged invertebrate group like spiders, ticks, and mites. What makes them unique in the group of arachnids is their tail. The tail is actually a stinger called a 'telson' that contains powerful venom that can kill an adult man. They are found in many places around the world, especially dry and arid regions except in Antarctica. They have a unique way of reproduction, that is different from other arachnids.
Scorpions, The Venomous Arachnid
There are about 1752 known species of scorpions in the world. The scorpion body is divided into three tagmata or parts. The first part is the cephalothorax (head), mesosoma (abdomen) and metasoma (tail). The chephalothorax consists of the carapace, eyes, mouth parts, claws (pedipalps) and four pairs of legs for walking. They have a thick exoskeleton that helps protect them from predators. There are seven segments, called opisthosoma on the mesosoma. There are a pair of spiracles on segments 3 to 7 that serve as a respiratory organ opening. The metasoma consists of five caudal segments and the last one (sixth) consists of the sting (telson). The telson contains a vesicle that consists of venom glands. It is interesting to note that when exposed to UV light or black light, a scorpion's body begins to glow. This is because of the presence of beta-carboline in the cuticle of the animal.
Life Cycle of Scorpions
The life cycle differs from species to species. Most of the scorpions reproduce sexually. There are certain species of scorpion that reproduce through parthenogenesis. This is a process where unfertilized eggs will develop into embryos. Once a scorpion molts one last time and reaches maturity, it will start undergoing parthenogenesis (unfertilized egg developing into an embryo). This process will continue throughout its life for reproduction. Let us now have a look at the sexual life cycle of scorpions.
The mating process of a scorpion is very complex. Scorpions use pheromones and vibrations to communicate and locate the opposite sex. Once they know they have met a scorpion of the opposite gender as well as the same species, they will begin with a mating ritual. The male scorpion will hold the pedipalps of the female in his own. Then, the scorpion pair will perform a 'dance' that is called the 'promenade à deux'. This dance is actually a process that will help the male to lead the female. This will help him find a suitable place to deposit his spermatophore. A mating ritual for a scorpion can involve several strange behavior. In some cases, the males carry out a cheliceral kiss. This means, the male chelicerae will grasp the female chelicerae, that appears like a kiss.
After the male finds a suitable place to deposit his spermatozoa, he will lead his lady over it. The spermatozoa will then enter her genital opercula. Once it does, the sperms are released and the female eggs are fertilized. It can take about an hour to over a day for the mating process to be completed. It depends on finding a suitable place to deposit the spermatozoa. The males have to hurry, if the process takes too long, the female will lose interest. She will break off and leave. After the process is complete, the male and female will separate. The males need to hurry and run away from the females. This is because there is a chance she may turn into a cannibal and eat him. However, this usually occurs only in some occasional cases.
The gestation period for a scorpion is very long. It may vary from a few months to even a year. This depends on species to species. The embryos develop in the female ovariuterus or in the special diverticula of the ovariuterus. Scorpions are viviparous and the young are born one by one. The young will quickly climb onto the mother's back and remain there for protection as well as regulation of their moisture level. In some species, mothers care for their young for a very long time. The number of young can depend on environmental factors and the species. They can number from just 2 to over a hundred. However, the average number of scorpions in one litter is about 8.
The young molt about 5 to 7 times depending on the species and reach maturity. The old exoskeleton splits and the scorpion comes out of it. The new exoskeleton is very soft. This makes the scorpion vulnerable to predator attack. Also, the scorpion has to move continuously, till the exoskeleton hardens (sclerotization). If the scorpion does not move, it will find it very hard to walk and move after the sclerotization is complete. One cannot say for sure what is the average lifespan of scorpions as they vary from 4 years to 25 years. There are many different types of scorpion species, whose average lifespan remains unknown.
As you can see, the life cycle of scorpions is very different from other arachnids. If you ever come across a scorpion, do not attempt to catch it, until and unless you know what you are doing. Their venom can prove to be fatal and therefore, it is better to leave them alone.