Oxalic acid's mode of action is likely (in my opinion) acidification of the moist footpads of the mites due to the high dissociation constant of oxalic acid. Arachnids secrete fluid to increase hydrostatic pressure,which OA acidifies, as it becomes a solution https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020485#:~:text=This%20finding%20implies%20that%20tarsal,and%20introducing%20rate%2Ddependent%20effects. Unless the mites evolve some sort of secretion of a strong base, to increase pH as soon as they step on the OA. How would they evolve a defense against a chemical burn? *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html