Emperor scorpion  (Pandinus imperator)

The emperor scorpion is listed on Appendix II of CITES (1).

The largest of scorpions, but not the longest, the emperor scorpion has a dark body ranging from dark blue/green through brown to black. The large pincers are blackish-red and have a granular texture. The front part of the body, or prosoma, is made up of four sections, each with a pair of legs. Behind the fourth pair of legs are comb-like structures known as pectines – these are longer in males and can be used by man to distinguish the sexes. The tail, known as the metasoma, is long and curves back over the body. It ends in the large receptacle containing the venom glands and tipped with the sharp, curved sting. Sensory hairs cover the pincers and tail, enabling the scorpion to detect prey through air and ground vibrations (3). When gravid (pregnant), the body of a female expands to expose the whitish membranes connecting the segments. The emperor scorpion fluoresces greenish-blue under ultraviolet light (4).

The emperor scorpion is found in Africa, including Benin, Burkina Faso, Côte d’Ivoire, Ghana, Guinea, Togo, Liberia, Mali, Nigeria, and Sierra Leone (5).

Inhabits both tropical forest and open savannas. The emperor scorpion burrows beneath the soil and hides beneath rocks and debris (3), and also often burrows in termite mounds (6).

The emperor scorpion engages in an elaborate courtship dance in which the male holds on to the female’s pincers or chelicerae, and moves around to find a suitable place on the ground to deposit his spermatophore. Once deposited, he manoeuvres the female over the area so she can receive the sperm (4) (7) (8). The female gives birth to between 9 and 32 live young after a seven to nine month gestation period, and they remain with her for some time. The young are white when born, but darken with each moult, reaching sexual maturity at four months (3). The emperor scorpion shows a degree of social behaviour, with burrows often inhabited by 15 or more individuals (9).

The emperor scorpion feeds on insects, arachnids, mice and small lizards, hunting them at night using its sensory hairs (trichobothria) (4). It has poor eyesight and is preyed upon by bats, birds, small mammals, large spiders, centipedes, large lizards and other scorpions (4) (6). As with other scorpions that possess large, strong pincers, the emperor scorpion uses the pincers to kill and manipulate prey, reserving the sting for larger prey or for use in self-defence (10) (7).

The emperor scorpion is threatened by over-collection for the pet trade (3) (7) (11), and by continuing destruction of its habitat through deforestation (5) (7) (11). The relatively small litter sizes and long generation times typical of scorpions may mean populations take a long time to recover from any losses (7).

The emperor scorpion was added to Appendix II of the Convention on International Trade in Endangered Species (CITES) due to concerns over the level of international trade in the species, and the potential effects on its populations. This listing means that international trade in the species should be carefully monitored and controlled, although those responsible for monitoring such trade are rarely scorpion experts, making identification of the different species a problem (1) (12). However, there is an increasing preference for captive-bred specimens in the pet trade (5), and this may go some way towards helping to prevent the emperor scorpion’s decline.

For further information on scorpions, see:

• The Scorpion Files:
  http://www.ub.ntnu.no/scorpion-files/index.php
• Scorpion Systematics Research Group, American Museum of Natural History:
  http://scorpion.amnh.org/index.html
• Scorpion Conservation 101:
  http://scorpionconservation101.weebly.com/

Authenticated (19/03/09) by Dr Lorenzo Prendini, Associate Curator (Arachnids and Myriapods) and Head of Scorpion Systematics Research Group, American Museum of Natural History.
http://scorpion.amnh.org

• Chelicerae: pair of appendages on the ‘head’ of an arachnid (spiders, scorpions, mites, harvestmen etc). In scorpions, these are claw-like and used in feeding (not to be confused with the larger pedipalps, or ‘pincers’).
• Gestation: the state of being pregnant (gravid); the period from conception to birth.
• Spermatophore: gelatinous jelly cone with a sperm cap deposited by a male during courtship and picked up by the cloacal lips of the female.

1. CITES (September, 2008)
   http://www.cites.org
2. The Scorpion Files (March, 2005)
   http://www.ub.ntnu.no/scorpion-files/p_imperator.htm
3. Animals – The Animal Information Centre (March, 2005)
   http://www.angelfire.com/mo2/animals1/scorpion/empscorp.html
4. The Big Zoo (March, 2005)
   http://www.thebigzoo.com/Animals/Emperor_Scorpion.asp
5. Prendini, L. (2004) On the scorpions of Gabon and neighbouring countries, with a reassessment of the synonyms attributed to Babycurus buettneri Karsch and a redescription of Babycurus melanicus Kovařík. California Academy of Sciences Memoir, 28: 235 - 267.
6. Prendini, L. (2009) Pers. comm.
7. Scorpion Systematics Research Group, American Museum of Natural History (November, 2008)
   http://scorpion.amnh.org/index.html
8. Polis, G.A. and Sissom, W.D. (1990) Life History. In: Polis, G.A. (Ed) The Biology of Scorpions.Stanford University Press, Palo Alto.
9. Mahsberg, D. (1990) Brood care and family cohesion in the tropical scorpion Pandinus imperator (Koch) (Scorpiones: Scorpionidae). Acta Zoologica Fennica, 190: 267 - 272.
10. Casper, G.S. (1985) Prey Capture and Stinging Behavior in the Emperor Scorpion, Pandinus Imperator (Koch) (Scorpiones, Scorpionidae). Journal of Arachnology, 13 (3): 277 - 283.
11. Prendini, L., Crowe, T.M. and Wheeler, W.C. (2003) Systematics and biogeography of the family Scorpionidae (Chelicerata: Scorpiones), with a discussion on phylogenetic methods. Invertebrate Systematics, 17: 185 - 259.
12. Lourenço, W.R. and Cloudsley-Thompson, J.L. (1996) Recognition and distribution of the scorpions of the genus Pandinus Thorell, 1876 accorded protection by the Washington Convention. Biogeographica, 72 (3): 133 - 143.