September 2011 The Maryland Entomologist Volume 5, Number 3 An Increasing Presence: The Lone Star Tick, Amblyomma americanum (Linnaeus) (Acari: Ixodidae) in Maryland John F. Carroll United States Department of Agriculture, Agricultural Research Service, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, Beltsville, Maryland 20705
[email protected] ABSTRACT: The Lone Star Tick, Amblyomma americanum (Linnaeus), has expanded its range in Maryland in recent years. The host-seeking seasonality of the larva, nymph, and adult of A. americanum is summarized for areas of Maryland where this species has invaded since 1990. Flag sampling showed well established populations of A. americanum in western Prince George‟s and Anne Arundel Counties. An indication of the successful establishment of A. americanum in the expansion zone was the presence of dense concentrations of host-seeking nymphs. INTRODUCTION In recent years, the Lone Star Tick, Amblyomma americanum (Linnaeus) (Acari: Ixodidae) (Figure 1, Figure 2), has been expanding it range and becoming more numerous in areas within its existing range (Ginsberg et al. 1991; Ginsberg and Zhioua 1996; Davidson et al. 1994; Means and White 1997; Childs and Paddock 2003; Lindgren et al. 2005; Carroll 2007). The core of the range of A. americanum is the southeastern and south central United States. The range attenuates northward along the Atlantic Coast, with populations on Long Island and Rhode Island (Keirans and Durden 1998). In Iowa, Lindgren et al. (2005) report a northward spread of A. americanum. Lone Star Ticks have long occurred in Maryland, but Carroll (2007) documented a westward spread of this species in the state since at least 1990.