High Temperature, Grasshopper Diet Boost Venom Production in Lab-Reared Scorpions
By Edward Ricciuti
The old saw “you are what you eat” apparently holds for scorpions. At least, it does when it comes to venom production which, say researchers in Pakistan, gets a big boost from a diet of grasshoppers.
Hot weather does the trick as well, according to a new study published in September in the Journal of Insect Science. The research was aimed at bettering the way venom is milked from scorpions for research and medical purposes.
Scorpion venom is a complex molecular brew of several biochemically active ingredients, and it has been used in both Western medicine and traditional healing in Asia and Africa to combat various diseases and to produce antivenom used to treat stings. The venom has been shown to have analgesic, anti-epileptic, anticancer, anti-inflammatory, antimicrobial and hemolytic properties. And dried bodies of scorpions have been used as analgesic and anti-epilepsy agents in China since the Song Dynasty (A.D. 960-1279).
The venom varies in composition among the 1,700 known scorpion species, about two dozen of which pose a mortal danger to humans. The two species used in the study, Androctonus finitimus and Hottentotta tamulus, are among the deadly two dozen. Environmental factors such as climate may also impact potency and production of venom. Understanding the effect of diet and temperature is essential for rearing and maintaining the scorpions in the laboratory for venom extraction, thereby reducing the need for scorpion collection from the wild.
The aim of the study—conducted by researchers at the Government College University, University of the Punjab, and University of Education in Lahore, Pakistan—was to compare the quantity and quality of venom extracted by manual and electrical methods and determine the effect of diet and temperature on venom production.
Scorpions inhabit all continents but Antarctica, but they thrive most in warmer climates. In temperate regions, they go into low gear for the winter. To study the effect of temperature on venom production, eight scorpions of each species were reared for a whole year in the laboratory. Scorpions were kept in temperatures similar to those in nature—15-20 degrees Celsius during winter and 30-40 degrees C in summer. Venom was extracted from the scorpions and recorded every month. The researchers found that higher temperature enhanced venom production.
Meanwhile, the study also showed that venom output from scorpions fed adult and nymph grasshoppers was far superior to that generated when scorpions were fed house crickets, houseflies, and moths.
Finally, the researchers also compared two methods of venom extraction, one manual and the other by electrical stimulation, in the course of the study. To milk venom, the scorpion was taped to a petri dish and its stinger inserted into a long, thin vial called a capillary tube. In one extraction procedure, manual stimulation of the scorpion’s abdomen caused the release of venom. In the other, the scorpion was administered an electrical shock via an electrode applied to the base of the stinger where the venom glands are located. The researchers found that the latter method, electrical stimulation, not only produced more venom but also produced venom with a higher amount of biochemically active ingredients than venom released by the manual method.
Journal of Insect Science
Ed Ricciuti is a journalist, author, and naturalist who has been writing for more than a half century. His latest book is called Bears in the Backyard: Big Animals, Sprawling Suburbs, and the New Urban Jungle (Countryman Press, June 2014). His assignments have taken him around the world. He specializes in nature, science, conservation issues, and law enforcement. A former curator at the New York Zoological Society, and now at the Wildlife Conservation Society, he may be the only man ever bitten by a coatimundi on Manhattan’s 57th Street.