SCIENTIFIC NAME: Androctonus Australis
ETYMOLOGY: Androctonus = “Man Killer” Australis = “Southern”
COMMON NAME: Egyptian Fat Tailed Scorpion, Tunisian Fat Tailed Scorpion, Yellow Fat Tailed Scorpion
DISTRIBUTION RANGE: Arabian and Sahara Desserts (Algeria, Chad, Egypt, Libya, Mauritania, Sinai, Somalia, Saudi Arabia, Sudan and Tunisia)
HABITAT: Hot and Arid Desserts in Mountain and plateau regions with dry sand or rocky soils with moderate ground cover like rocks. Often found in close proximity to human dwellings.
APPEARANCE: Large species, the adults attain 10 cm, Color pale yellow more or less ochre with sometimes darker zone on the boby. Sternites pale yellow. Metasomal segment I-IV yellowish, with carinae ventrally brownish, segment V and vesicle darker. Telson with aculeus reddish at base and brownish at the end. Pedipalps yellow or brownish yellow, with finger of pedipalp darker, legs pale yellow. Carapace with carinae and granules well developed and lightly marked on tergites. Metasomal segment strongly widened backwards, metasomal segments I-IV with dorsal carinae strongly marked, with spiniform granules on the poterior side. Vesicle with some granules ventrally; aculeus lightly curved as long as the vesicle. Chela rounded with finger moderately long. Fixed and movable finger of pedipalp bear 12-14 rows of granules. (Source: MES Scorpions: http://bultel.p.free.fr)
TOXICITY and VENOM: Neurotoxic with cardiotoxic components. LD50 values 0.32 to 6.00 mg/kg (lower values = greater toxicity levels). Toxicity levels vary among geographic populations. Based on published medical reports and LD50 values, this species is considered to be one of the two most medically significant scorpion species in the world and presents a health hazard to the peoples of many North African and Middle Eastern regions. While the LD50 values for Androctonus australis are not as low as those for Leiurus quinquestriatus, it is still considered by most researchers to be on par with L. quinquestriatus due to its ability to inject copious quantities of venom (up to 2 mg) into a victim causing a broad-range of local to severe physiological responses and in a small number of cases, mortality.
How many actually die from envenomations by this species? Not as many as commonly believed. Balozet (1971) reported on 1,260 cases of scorpion envenomations attributed to A. australis in southern Algeria, with only 24 (1.9%) fatalities during a 16-year period (1942–1958). Goyffon et al. (1982) in a similar study from Tunisia reported that during a 10-year period (1967–1977), 2,672 envenomations were attributed to A. australis with only 12 (0.5%) fatalities reported. Overall, 3,932 envenomations were reported with only 36 (0.9 %) resulting in fatalities.
In comparison, Touloun et al. (2001) in a study on scorpion envenomations in southwestern Morocco reported that Androctonus mauritanicus is responsible for 60% of all fatalities reported for that region during a short 4-year period (1994–1998). In all studies, the majority of reported fatalities are among infants and small children. A recent 3-year study (Soulaymani et al., 2007) involving 4,089 patients of scorpion envenomations in Khouribga Province, Central Morocco, indicated that young age, low body weight, symptoms at admission and time elapsed between envenomation and admission were correlated with poor outcome. In the same study, 25,000 envenomations are reported occurring in Morocco each year with 90% of fatal envenomations occurring in victims under 10-years of age. The primary scorpion species associated with lethal outcome in the study region was Androctonus mauritanicus with this species considered the most lethal scorpion in Morocco.
Based upon the above cited studies and others not listed, Androctonus mauritanicus is on par with A. australi sand L. quinquestriatus in producing large numbers of envenomations resulting in adult and pediatric morbidity and low to moderate incidence rates of pediatric mortality in young victims (under 15-years of age) per annum. Adult mortality is extremely rare and when reported typically involves negative outcomes as a result of complications due to existing health issues in victims.
However, when using LD50 values to express the toxicity of a scorpion’s venom and its potential for lethality in humans, we must exercise caution and objectivity when addressing the issue of the ability of any venom to produce mortality in humans.
An LD50 test is the standard method used to determine the toxicity potential of venoms based on the amount of venom measured in milligrams per kilogram needed to kill 50% of test subjects; typically various strains of mice. Comparative evaluations across various studies using different strains of mice and rats of different age and gender exhibit different levels of susceptibility to the venom of a particular species often producing varied LD50 values (Kumar & Deshpande 1993; Sandoval & Dorce 1993; Clot-Faybesse et al. 2000; Nunan et al. 2001). LD50 values may also be affected by the physiologic condition of the scorpions used in such tests and furthermore, the venom toxicity of a particular species may vary across different populations throughout the entire geographic distribution range of a species, and while the LD50 of specimens from one region may produce potentially dangerous toxicity values; specimens from a different region may only produce LD50 values of moderate or marginal toxicity.
Lastly, while many studies have been conducted on envenomations by A. australis, these studies are typically limited to a single area and only record the number of victims that actually seek medical assistance at hospitals and medical facilities. To date, no published envenomation study is complete and reported mortality rates are artificially high due to the inability of researchers to provide a complete total number of all envenomations that occur in a region over a period of time. Many victims of envenomation may not report the envenomation to poison control centers or medical facilities due to various factors such as lack of transportation or communication or relying on self-treatment with traditional remedies at home. Due to these factors, mortality rates probably account for a very small number of envenomations in all world regions where medically significant scorpion species occur. (Source: The Venom List: SOTM by LKR)
HOUSING: I house my 3 Androctonus Australis Adults in a 10x10x10 Terrarium, while my 3rd instar Androctonus Australis Lybicus in a 4x4x4 Clear Tupperware. Height and a secure cover of the terrarium is important for this species to prevent escapes. You don’t want this scorpion roaming freely in your house. High ventilation is a must for this species so that there will be constant air flow. My Substrate is Pure Fine Sand, washed and cooked to remove all bacteria’s and fungus present in the sand. Ventilation and Sterilized substrate are important factors in dessert type species to prevent development of mycosis. I provide rocks and barks as hide, this hides are necessary for this species since at day time they want to hide. This also prevents stress making your scorpion happy and worry free. Androctonus Australis are opportunistic burrowers; they dig scrapes under rocks and barks. Re housing really depends on how dirty the substrate gets, most likely every 5 to 6 months.
FEEDING and MISTING: I feed my adults 1 adult lateralis per week while my 3rd instar, every 4 days. While I provide water dish every 2 weeks for my adults and mist once a week for my 3rd instar. Although this species are dessert species they like to drink water, I witnessed my female drink from the water dish.
BEHAVIOR: Despite its bad reputation as the world’s deadliest scorpion, Androctonus Australis are very shy and passive species, their first reaction to disturbance or threat is to run and hide. But make no mistake this species are very fast, so do not under estimate its less aggressive behavior. 1 envenomation from this species can send you to heaven or hell. Make sure to use tweezers to remove or place an object in the terrarium to avoid accidents.
Androctonus Australis are ambush predators; they sit and wait in their hides waiting for a prey to pass by.
GROWTH and LIFE SPAN: They are medium to slow grower species. Average Life Span is 4 to 5 years.
SEXING: The most accurate way of sexing Androctonus Australis is through pectine count. Males have 30 to 38 pectine count while females have 22 to 29 pectine count.
Another way of sexing is Females have thinner chela and more robust in body while males have bulbous chela and slender body.
BREEDING: I haven’t experienced actual mating of this species since my 2 attempts of mating them were unsuccessful due to some circumstances either the female is already gravid or not yet sexually mature. In my 2 attempts, what I did was conditioned both male and female by feeding them as much as I can in 5 days and let the female get familiar with the breeding enclosure. I placed the male in the female’s enclosure. Once inside the male started to shake and searched for the female. Then the male attempted to approach the female but the female showed a sign of refusal by using her metasoma to push away the male. The female did not show any aggressive behavior towards the male. After a while the male suddenly run away. I decided to remove the male and try again after a week. Same results happened in my second attempt. Gestation period for this species is 6 to 9 months with an average brood of 40 scorpion slings.
