0 ▁million ▁and ▁have ▁been ▁known ▁to ▁spread ▁dise ases ▁affect ing ▁local ▁b iod iversity . ▁Unfortunately , ▁the ▁introduction ▁of ▁the ▁to ads ▁has ▁not ▁only ▁caused ▁large ▁environmental ▁det r iment , ▁but ▁there ▁is ▁no ▁evidence ▁that ▁they ▁have ▁affected ▁the ▁can e ▁be et les ▁that ▁they ▁were ▁introduced ▁to ▁pre y ▁upon . ▁The ▁to ads ▁have ▁stead ily ▁expanded ▁their ▁range ▁through ▁Queensland , ▁reaching ▁the ▁border ▁with ▁New ▁South ▁Wales ▁in ▁ 1 9 7 8 ▁and ▁the ▁Northern ▁Territ ory ▁in ▁ 1 9 8 4 . ▁The ▁to ads ▁on ▁the ▁western ▁front ier ▁of ▁their ▁advance ▁have ▁evol ved ▁larger ▁legs ; ▁this ▁is ▁thought ▁to ▁be ▁related ▁to ▁their ▁ability ▁to ▁travel ▁farther . ▁As ▁a ▁consequence ▁of ▁their ▁longer ▁legs , ▁larger ▁bodies , ▁and ▁faster ▁movement , ▁about ▁ 1 0 % ▁of ▁the ▁leading ▁edge ▁can e ▁to ads ▁have ▁also ▁developed ▁ar th rit is . ▁It ▁was ▁estimated ▁that ▁can e ▁to ads ▁migr ate ▁at ▁an ▁average ▁of ▁ 4 0 ▁kilometres ▁( 2 5   m iles ) ▁per ▁year ▁as ▁of ▁ 1 9 9 4 , ▁but ▁new ▁research ▁in ▁ 2 0 1 4 ▁indicated ▁that ▁the ▁migration ▁rate ▁had ▁increased ▁to ▁ 6 0   km ▁( 3 7 ▁miles ) ▁per ▁year ▁on ▁the ▁western ▁front . ▁ ▁By ▁ 2 0 1 9 ▁they ▁had ▁become ▁a ▁p est ▁in ▁the ▁Tor res ▁Stra it ▁Islands , ▁probably