Tetratrichobothrius flavicaudis, commonly known as the European yellow-tailed scorpion, is a small black scorpion with yellow-brown legs and tail (metasoma). Adults measure about 35–45 mm (1.4–1.8 in) long. It has relatively large, strong claws (pedipalps) and a short, thin tail. This species is native to Southern Europe and Northwest Africa, but an introduced population exists in the United Kingdom.
Distribution
The native range of Tetratrichobothrius flavicaudis extends through Northwest Africa and Southern Europe. However, it has also been accidentally introduced into the United Kingdom at Sheerness Dockyard on the Isle of Sheppey, Kent, and parts of east London. The introduction likely occurred in the early 19th century via a shipment of Italian masonry. By 2013, the resulting colony numbered between 10,000 and 15,000 individuals, making it the northernmost population of scorpions outside the Americas.
How does the venom of Tetratrichobothrius flavicaudis compare to other scorpions
Comparing the Venom of Tetratrichobothrius flavicaudis to Other Scorpions
Scorpions are often feared due to their venomous stings, but not all scorpion venoms are created equal. The European yellow-tailed scorpion, Tetratrichobothrius flavicaudis, is known for its relatively mild venom, especially when compared to more dangerous scorpion species. This article explores how the venom of Tetratrichobothrius flavicaudis compares to other scorpions, examining factors such as venom potency, effects, and evolutionary adaptations.
Venom Potency and Toxicity
The potency of scorpion venom is commonly measured using the median lethal dose (LD50), which indicates the amount of venom required to kill 50% of a test population, typically mice. The LD50 values provide a quantitative measure of venom toxicity, allowing for comparisons between different scorpion species.
Tetratrichobothrius flavicaudis Venom
The venom of Tetratrichobothrius flavicaudis is considered mild and poses a low health risk to humans. Stings from this scorpion typically result in localized pain and swelling, with rare cases of nausea. There have been isolated reports of neurological symptoms in children following a sting, but these are not common. Overall, the venom is less harmful than that of many other scorpions, such as those in the Buthidae family.
Comparison with More Venomous Scorpions
In contrast, scorpions like Androctonus mauretanicus and Androctonus australis hector possess highly toxic venoms. Studies have shown that the venom of Androctonus mauretanicus is significantly more potent than that of Tetratrichobothrius flavicaudis, with an LD50 value indicating much higher lethality. Similarly, the venom of Centruroides edwardsii, a bark scorpion, is known for its severe effects, including intense pain and potentially life-threatening symptoms.
Factors Influencing Venom Potency
Several factors influence the potency of scorpion venom, including scorpion size, pincer size, and evolutionary adaptations.
Size and Venom Potency
Research indicates that smaller scorpions tend to have more potent venoms compared to larger ones. This is because smaller scorpions rely more on their venom for defense and prey capture, whereas larger scorpions can use their physical strength and pincers. For example, the Deathstalker (Leiurus quinquestriatus), a relatively small scorpion, has one of the most potent venoms among scorpions.
Pincer Size
The size of a scorpion’s pincers also correlates with venom potency. Scorpions with smaller pincers tend to have more potent venom, as they rely more on their venomous sting for defense and hunting. Conversely, species with large, robust pincers often have less potent venom because they can subdue prey and defend themselves using their physical strength.
Evolutionary Trade-offs
The evolutionary trade-offs between physical attributes and venom potency play a significant role in determining a scorpion’s overall threat level. Scorpions that have evolved larger pincers may invest less energy in producing potent venom, while those with smaller pincers compensate with more toxic venom. This trade-off is evident in the diverse range of scorpion species and their varying venom potencies.
Clinical Implications
Understanding the differences in venom potency among scorpions has important clinical implications, especially in regions where scorpion stings are common. Identifying the scorpion species responsible for a sting can help medical professionals administer appropriate treatment more quickly. For instance, stings from highly venomous scorpions like Androctonus species require immediate medical attention and possibly antivenom, whereas stings from Tetratrichobothrius flavicaudis are generally less severe and may only require symptomatic treatment.
The venom of Tetratrichobothrius flavicaudis is relatively mild compared to that of more dangerous scorpions. Factors such as scorpion size, pincer size, and evolutionary adaptations contribute to the varying potency of scorpion venoms. Understanding these differences is crucial for effective clinical management of scorpion stings and for appreciating the diverse strategies scorpions use for survival. While Tetratrichobothrius flavicaudis may be a “tiny titan” in its own right, its venom is far less formidable than that of its more lethal relatives.
Habitat
In warm temperate climates, this species can be found in built-up areas. In the UK, the scorpions occupy cracks and holes in walls where the mortar pointing has crumbled away.
Venom
Tetratrichobothrius flavicaudis is mildly venomous and rarely uses its stinger. Its sting is less painful to humans than a bee sting.
Reproduction
The gestation period for Tetratrichobothrius flavicaudis ranges from 10 to 14 months, depending on food availability and climate. After mating, a pregnant female seeks a secluded, humid place to give birth to live young, numbering from a few to about 30. These newborns are white, soft, and swollen. The mother raises her forelegs to facilitate the release of the young, which then climb onto her back, remaining there until their first moult, which occurs about six days later. After this, the young scorpions start to wander around the surrounding area but stay close to the hiding place for a few days. They reach adulthood in 1–2 years.
Feeding
Tetratrichobothrius flavicaudis is an ambush predator. It lies motionless at the entrance to its lair, moving quickly to capture prey that wanders by. The main prey of T. flavicaudis are woodlice, although it also captures most small insects. Cannibalism has been noted in colonies of T. flavicaudis. Thanks to their low metabolic rate, these scorpions can go for long periods without food, subsisting on as few as four or five woodlice per year.
Tetratrichobothrius flavicaudis, the European yellow-tailed scorpion, is a fascinating species with unique adaptations that allow it to thrive in various environments. From its introduction to the UK to its ambush predation tactics, this tiny titan continues to intrigue scientists and enthusiasts alike.
