Effects of selected meteorological factors on diurnal questing of Ixodes scapularis and Amblyomma americanum (Acari : Ixodidae)

The diurnal questing behavior of adult Ixodes scapularis Say and Amblyomma americanum (L.) were monitored in the field to determine whether ticks woul d be collected with greater frequency during certain times of the day and u nder certain ambient meteorological conditions. Temperature and relative hu midity explained a significant amount of the total variation in tide collec tions. Although both species were collected during every period, I. scapula ris adults tended to quest earlier and later in the day when temperatures w ere lower and relative humidity higher, whereas A. americanum were collecte d with greater frequency in late morning and early afternoon during periods of higher temperatures and lower humidity. Questing of I, scapularis adult s was observed at temperatures as low as -0.6 degreesC, whereas no adult A. americanum were collected below 4.4 degreesC. The questing temperature thr eshold for I. scapularis adults observed in this study was below that repor ted previously. The implications of these temporal activity patterns on the assessment of disease transmission risk and sampling bias are also discuss ed.