Meeting Abstract
The pallid bat (Antrozous pallidus) is a gleaning bat found in the western United States and Mexico. It hunts a wide variety of ground-dwelling prey, including scorpions. Anecdotal evidence indicates that the pallid bat is resistant to scorpion venom, but no systematic study has been performed. Here we show with behavioral measures and direct injection of venom that the pallid bat is resistant to the venom of the deadly Arizona bark scorpion, Centruroides sculpturatus. Our results show that the pallid bat is stung multiple times during a hunt, and the venom has no effect on its behavior. We also tested pallid bats from three regions in the southwest USA to test whether venom resistance varied with sympatry or allopatry to C. sculpturatus and found no difference in venom resistance. Scorpion venom is a cocktail of molecules, some of which hyper activate voltage-gated sodium ion channels and cause intense pain. Dorsal root ganglia (DRG) contain nociceptive neurons and are principal targets of scorpion venom. To understand if mutations in specific ion channels underlie venom resistance, the transcriptome of the pallid bat DRG was generated. As sodium channels are the principal targets of scorpion venom, we identified amino acid substitutions present in the pallid bat DRG which may grant venom resistance. These substitutions are similar to corresponding amino acids in sodium channel isoforms responsible for reduced venom binding activity. The substitution found previously in grasshopper mice rendering venom resistance is not present in the pallid bat, showing that the pallid bat has acquired venom resistance using a different mechanism. Future studies will test the amino acid substitutions identified in the pallid bat DRG using patch clamping and cell lines to understand mechanisms of venom resistance.
