title: Density of Ixodes scapularis ticks on Monhegan Island after complete deer removal: a question of avian importation?
abstract: Questing adult blacklegged tick (Ixodes scapularis Say) abundance declined markedly three years after the 1999 removal of white-tailed deer (Odocoileus virginianus Zimmermann) from Monhegan Island, ME. Since 2000, subadult ticks have not been found on Norway rats (Rattus norvegicus Berkenhout); questing nymphs have not been found since 2002. This suggested I. scapularis was reintroduced annually via bird importation of subadult ticks, but unable to complete its two-year life cycle on the island due to lack of deer. To investigate this, we used uncertainty analysis to estimate 1) questing adult ticks/ha that would result from avian importation of nymphs, and 2) questing adult ticks/ha on Monhegan Island, using bird capture and tick burden data from Appledore Island, ME, flagged tick data from Monhegan Island, and ten uncertain parameters. During the deer-fed period (1990-2001), estimated tick density on Monhegan Island was 18 times greater than that of imported ticks. During the post-deer-fed period (2002-2008), Monhegan Island tick density was equivalent to imported tick density. This supported the premise that all I. scapularis ticks on Monhegan Island have been bird-derived since 2002.
authors.affiliation: Maine Medical Center Research Institute, Center for Vector-borne Disease, 75 John Roberts Rd. #9B, South Portland, ME 04106, USA.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Elias
authors.forename: Robert P
authors.initials: RP
authors.lastname: Smith
authors.forename: Sara R
authors.initials: SR
authors.lastname: Morris
authors.forename: Peter W
authors.initials: PW
authors.lastname: Rand
authors.forename: Charles
authors.initials: C
authors.lastname: Lubelczyk
authors.forename: Eleanor H
authors.initials: EH
authors.lastname: Lacombe
mesh_terms: D000818:Animals; D001717:Birds / Q000469:parasitology; D003670:Deer / Q000469:parasitology; D005843:Geography; D018884:Ixodes / Q000254:growth & development*; D008281:Maine; D011156:Population Density