Different Populations of XXXX Nymphs Exhibit Differences in Questing Behavior That Have Implications for @entity1 Lyme Disease Risk.

@entity1 @entity3001 @entity3966
UNASSIGNED: Animal behavior can have profound effects on pathogen transmission and disease incidence. We studied the questing (= host-seeking) behavior of @entity3966 ( @entity3966 ) nymphs, which are the primary vectors of @entity3001 in the eastern United States. @entity3001 is common in northern but not in southern regions, and prior ecological studies have found that standard methods used to collect host-seeking nymphs in northern regions are unsuccessful in the south. This led us to hypothesize that there are behavior differences between northern and southern nymphs that alter how readily they are collected, and how likely they are to transmit the etiological agent of @entity3001 to @entity1 . To examine this question, we compared the questing behavior of @entity3966 nymphs originating from one northern ( @entity3001 endemic) and two southern (non-endemic) US regions at field sites in Wisconsin, Rhode Island, Tennessee, and Florida. Laboratory-raised uninfected nymphs were monitored in circular 0.2 m2 arenas containing wooden dowels (mimicking stems of understory vegetation) for 10 (2011) and 19 (2012) weeks. The probability of observing nymphs questing on these stems (2011), and on stems, on top of leaf litter, and on arena walls (2012) was much greater for northern than for southern origin ticks in both years and at all field sites (19.5 times greater in 2011; 3.6-11.6 times greater in 2012). Our findings suggest that southern origin @entity3966 nymphs rarely emerge from the leaf litter, and consequently are unlikely to contact passing @entity1 . We propose that this difference in questing behavior accounts for observed geographic differences in the efficacy of the standard sampling techniques used to collect questing nymphs. These findings also support our hypothesis that very low @entity3001 incidence in southern states is, in part, a consequence of the type of host-seeking behavior exhibited by southern populations of the key @entity3001 vector.
