Notes on the breeding of Hottentotta pachyurus Pocock , 1897 ( Scorpiones : Buthidae )

The communication presents a short description of the breeding behavior exhibited by a female scorpion Hottentotta pachyurus under laboratory conditions along with the gestation period and number of juveniles born. The communication also states the probability of Hottentotta pachyurus and other Indian scorpions to be parthenotes.

On 9 May 2007 we collected a live specimen of a female scorpion identified as Hottentotta pachyurus (Image 1) from near Karla caves, Lonavala, Maharashtra from under a boulder with Hemidactylus cf.brookii (Reptilia: Gekkonidae) being one of the sympatric species.The scorpion was black with the tarsus of the pedipalps distinctively reddish-brown; measuring ca.25mm in total length.
The live scorpion was housed in a plastic box, the substrate of which was comprised of loose soil and bark pieces, and mealworms were introduced into the box for it to feed upon.The scorpion would hold the mealworms between its pedipalps, sting them, and then proceed to consume them once they were paralyzed.The scorpion grew to about 41.76mm with a distinctly bulging mesosoma.On 22 January 2008 at 2230hr the scorpion was observed in the corner of the box and on 23 January 2008 at 1100hr 16 hatchlings were observed on its back.The newly born young had dark rufous carapaces and mesosomas, with light colored legs that contrasted with their metasomas and pedipalps, which were a shade of orange.As they grow, the entire body color changes to dark brownishblack ultimately changing to overall black at adulthood.Gour-Broome & Zambre (2007) reported juvenile Hottentotta pachyurus to have a reddish body and black legs.By 24 January 2008 three of the juveniles were found dead and were later consumed by their siblings.By 25 January most of the juveniles had abandoned their mother, molted, and were observed feeding upon their exoskeletons (Images 2 & 3).The juveniles ranged in size from 7.02 to 10.70mm and were active and alert, stinging at the slightest provocation.Later they were released at the site where the adult female was collected.During the prolonged gestation period of eight months and 13 days (under observation), the female did not molt.When the female was collected, she did not show any signs of aggression, but as the time of parturition approached she would get agitated and sting at the slightest provocation.
Members of the family Buthidae are known to have a minimum gestation period of 1 month (Orthochirus innesi Simon) and a maximum gestation period of 10 months (Buthus occitanus Amoreux).Litter sizes vary from 5 to 105 (Polis 1990).Hottentotta pachyurus is presently reported to have a gestation period exceeding eight months and 13 days under laboratory conditions as mating did not occur in captivity.
During the period of captivity an individual of Hottentotta tamulus Fabricius 1798 was introduced (in the month of June 2007) into the housing box, agitating the female H. pachyurus.As H. tamulus entered into the striking range of H. pachyurus it was repeatedly stung, and after stinging H. pachyurus once, immediately retreated into a corner.The scorpions were separated after this incident.The H. tamulus was retained and observed for a week after being stung and was then released.No sign of envenomation was evident in the form of abnormal behavior or swelling.
Since mating did not occur in captivity we assume that H. pachyurus might be parthogenic, similar to two other species of the genus Hottentotta namely, H. hottentotta and H. caboverdensis (Lourenço & Ythier 2007;Lourenço et al. 2007) but this needs further investigation.Lourenço et al. (2007) mentions 10 species of the family Buthidae to be parthogenic, namely Tityus serrulatus, Tityus uruguayensis, Tityus columbianus, Tityus trivittatus, Tityus stigmurus, Tityus metuendus, Ananteris coineaui, Centruroides gracilis, Hottentotta hottentotta and Liocheles australasiae.During a survey in an area less than 1km 2 at Pune, only two males in a total of 30 specimens of Hottentotta tamulus were observed (Amod Zambre pers.comm.).This indicates that the sex ratio of females to males may be high.A further detailed study is required to ascertain parthenogenesis in Indian scorpions.
Most of the work pertaining to Indian species of scorpions has dealt with the toxicity of their venom.Thus this report on the breeding biology of Hottentotta pachyurus adds some information on the natural history and ecology of this little known buthid.