The scorpion, a tiny, nonvenomous predator that lives in showers in Jerusalem and the sewer system, as well as in dark caves in the Galilee, reproduces in a virgin reproduction system in which all offspring are clones of the mother – but the limited habitat, human activity and the climate crisis are pushing the blind species to the brink of extinction.
For those who find the words "scorpions" and "spiders" uncomfortable, we also wanted to get to know the "scorpions." But don't worry, the scorpion is a tiny, cute animal that, if you encounter one at home, remember that it eats mosquitoes. Besides, you'll probably not encounter a scorpion at all, but a scorpion that is two drops of water from its mother, grandmother, and great-grandmother. We spoke with Prof. Efrat Gavish-Regav, a researcher in the Department of Entomology, Institute of Environmental Sciences, Faculty of Agriculture, Food and Environment, and curator of the National Arachnid Collection at the Hebrew University of Jerusalem, about these fascinating creatures.
What is a scorpion? Is it a scorpion or a spider?
"Neither this nor that. The Scorpions are a close series." For spiders", but they lack silk glands in the abdomen and lack venom. They have a body structure of head-thorax and abdomen like that of spiders." The series Scorpions, Arachnids and Scorpions are under the department of Arachnids, which Gavish-Regav has been studying for more than 25 years.
Is the scorpion dangerous to humans?
"No, there is no reason to be afraid of scorpions. They have no venom, they have no sting, and they have nothing dangerous. If they see us, they usually try to escape into holes in the wall or places where they can hide. Scorpions are lovable, small, and cute creatures. They are about a centimeter to a centimeter and a half in size."
What do they eat?
"Scorpions are important predators of small arthropods, such as mosquitoes, flies, and other insects in the habitats they inhabit. They capture their prey with their spiny antennae."
Where can I find them?
"They love dark, damp places. So far, two species of scorpions are known in Israel."
"The Mediterranean scorpion was originally described from one of the Greek islands and is known today in the eastern Mediterranean: Turkey, Greece, Israel, Jordan and Egypt. The Mediterranean species can be found in human habitations, usually in damp and dark rooms, toilets and showers. They are also found in the sewer system in Jerusalem and Haifa. It is believed that humans transport them from place to place as 'hitchhikers', since they are flat and small."
"The other sex, the blind scorpion, We described Together with colleagues in 2016. It is known to us only from two small caves in the Galilee, and therefore it is considered endemic to Israel (found only here and not elsewhere, by him) and is in danger of extinction."
Only in two caves? How did he get there?
"Scorpions are very fond of damp and dark places, such as ancient cisterns found in ruins. These cisterns are usually caves that have been used by humans, who coated the walls of the cave from the inside with a type of plaster or stucco to retain water. It is possible that several million years ago, when the climate here was wetter, the blind scorpion was common throughout the Galilee. Following drying, it remained a relict (relic) that survived only in the two caves thanks to conditions of high and constant humidity in the cisterns."
"According to another hypothesis, the origin may be in a single cave, and this is a relatively young distribution expansion, which occurred recently in evolutionary time."
What is one of the surprising things about Scorpios?
"One of the most fascinating features of scorpions is their ability to reproduce through virgin reproduction (parthenogenesis). This is a situation in which females can produce fertile eggs without the need for a male to fertilize them in order for embryos to develop. The offspring are essentially a copy of the mother. Virgin reproduction is relatively common in this series. In most of the distribution of the Mediterranean scorpion in the Levant region (the eastern basin of the Mediterranean Sea), there are no males, only females. The blind species in Israel is entirely a genetic clone, since no males have been found in populations in the country."
"To test this, we raised adult females in the laboratory. We took offspring from females that had reproduced, separated them, and raised them separately throughout. We demonstrated that in this way the females, who had not encountered any other individuals, produced fertile eggs that developed into both embryos and young individuals. This proves that they definitely have virgin reproduction."
Does that mean all blind scorpions are exactly the same?
"Despite virginity and genetic identity, We discovered "There is phenotypic variation (differences in traits that are expressed, for example, in external appearance, etc.) in populations, even in the same cave. From one of the caves in the Galilee that was supposed to contain only the blind scorpion, we suddenly discovered that some of the individuals have eyes. This was very surprising because the easiest morphological sign we had in the field to identify between species was 'has eyes or no eyes.'"
"In molecular (genetic) tests, we found individuals of the blind scorpion species with a level Different eye degeneration"These are individuals in the same cave, which are genetic copies of the same mother who replicated herself. Some are completely blind, some have only the internal structure of the eye, and others have very small lenses. To add to the confusion, we found that the two species (the blind and the Mediterranean) live together in one of the two caves where we found the blind scorpion. There are also individuals of the Mediterranean scorpion species in the same cave with eyes that have a certain degeneration. This raised a lot of questions, because even though they live together, there is no reproduction between them."
Does virgin breeding, which creates a population with low genetic diversity, make them more susceptible to the climate crisis?
"In principle, yes. The big disadvantage of virgin breeding is that if environmental conditions change suddenly, then the population does not have the genetic diversity to cope with the change."
"Scorpions are lovers of dark, humid habitats. Climate change, which entails long dry periods, may affect their survival. Habitats such as deep caves are characterized by constant heat and humidity conditions throughout most of the year, and are less affected by what happens outside. Species that live in caves are much more sensitive to changes. Based on this general assumption, we assume that scorpions are sensitive to changes in the environment. However, if the blind species originated recently in evolutionary terms (less than a million years ago) and is only now spreading, it may not be very sensitive, but we really don't know."
What else threatens the Scorpions?
"The main threats are human activity. Since the blind scorpion is only found in two caves, any damage to the cave could lead to extinction. There is also concern about collection for recreational purposes." Animal trafficking"It's complicated, because very few arthropods, and certainly scorpions, are on the list of protected species in Israel. We are currently working on adding the blind scorpion to the list."
What can we do?
"The general public can support In cave conservation "And avoid collecting animals for trade purposes. The scorpion is a good little animal that needs to be protected."
More of the topic in Hayadan:
