Comparison of Isoflurane and Carbon Dioxide Anesthesia in Rose-Haired Tarantulas (Grammostola rosea)
American Association of Zoo Veterinarians Conference 2006
Ryan De Voe1, DVM, MSpVM, DACZM, DABVP (Avian); Dan Dombrowski2, MS, DVM; Gregory Lewbart3, MS, VMD, DACZM
1North Carolina Zoological Park, Asheboro, NC, USA; 2North Carolina Museum of Natural Science, Raleigh, NC, USA; 3Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA


Thirty-two sub-adult to adult rose-haired tarantulas (Grammostola rosea) were randomly divided into two groups. One group was anesthetized with 5% isoflurane in oxygen and the other with 100% carbon dioxide. The tarantulas were anesthetized in a chamber fashioned from a clear plastic jar. Isoflurane was delivered by a standard veterinary vaporizer. Carbon dioxide was supplied via a laparoscopy insufflation unit. Times to first effect, loss of righting reflexes, loss of movement with and without external stimuli, and recovery time were recorded (Table 1). Subjective comments regarding the anesthesia episodes were also recorded. Statistically significant differences were detected between the groups in all of the recorded times. Animals anesthetized with carbon dioxide had a shorter time to first effect and loss of movement as well as a reduced recovery time in comparison to those in the isoflurane group. Subjectively, the tarantulas anesthetized with carbon dioxide seemed distressed during induction and recovered in an agitated state. Tarantulas anesthetized with isoflurane had a smoother induction and recovery, but often displayed some movement in response to stimuli for extended periods of time. All tarantulas recovered completely and have remained healthy for greater than 2 years following the experiment, with the exception of two animals which died from apparently unrelated causes.

Both anesthetic agents appear to be safe and efficacious as used in this study. It should be noted that repeated carbon dioxide anesthesia causes impaired reproduction, growth and survivability in a number of invertebrate species.1-4 The tarantulas in this study did not show any obvious ill effects following carbon dioxide or isoflurane anesthesia, but reproductive behavior and capability was not evaluated.

Table 1. Comparison of carbon dioxide and isoflurane anesthesia characteristics in rose-haired tarantulas (Grammostola rosea)


Mean time to onset (sec) " SD

Mean time to loss of righting reflex (sec) " SD

Mean time to loss of movement (sec) " SD

Mean time to recovery (sec) " SD

Carbon dioxide (n=16)





Isoflurane (n=16)







The authors would like to thank Shane Christian for managing the tarantula colony at the North Carolina State College of Veterinary Medicine.

Literature Cited

1.  Barron, A. 2000. Anaesthetising Drosophila for behavioural studies. J. Insect Physiol. 46(4):439–442.

2.  Caciagli, P. 1991. Effect of anaesthesia with carbon dioxide on vectoring ability and survival of the planthopper Laodelphax striatellus. Ann. Appl. Biol. 199(2):257–264.

3.  Mbata, G. 1998. Comparative effect of short-term exposures of Callosobruchus subinnotatus to carbon dioxide, nitrogen, or low temperature on behavior and fecundity. Entomologia Exper. et Applicata 89(3):243–248.

4.  Tanaka, A. 1982. Effects of carbon dioxide anesthesia on the number of instars, larval duration and adult body size of the German cockroach, Blattella germanica. J. Insect Physiol. 28(10):813–822.


Speaker Information
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Ryan De Voe, DVM, MSpVM, DACZM, DABVP-Avian
North Carolina Zoological Park
Asheboro, NC, USA

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