From the result of a 8 month study about the position on vegetation of Rhipicephalus bursa larvae in relation to the climatic parameters, including data obtained from pre- and post- winter minimum temperature and light intensity periods, a change in the response to meteorological values can be deduced. Before the onset of a winter inactivity phase, R. bursa larvae display a clear response to the ’accumulated’ climatic series (position on vegetation being highly correlated with the sum of the climatic parameters, from the beginning of the experience to the moment of data recording) and, after the end ofthis phase, the larvae show a greater response to the ’mean’ climatic series and, in contrast with the results obtained for the first part of the trial, ’accumulated’ series lead to a meager response of position. The mathematical relations and the ecological significance of these results are discussed.