Data from: Towards an evolutionary understanding of questing behaviour in the tick Ixodes ricinus

The tick Ixodes ricinus finds its hosts by climbing vegetation and
adopting a sit-and-wait tactic. This “questing” behaviour is known to be
temperature-dependent, such that questing increases with temperature up to
a point where the vapor pressure deficit (drying effect) forces ticks down
to rehydrate in the soil or mat layer. Little if any attention has been
paid to understanding the questing of ticks from an evolutionary
perspective. Here we ask whether populations from colder climatic
conditions respond differently in terms of the threshold temperature for
questing and the rate of response to a fixed temperature. We find
significant variation between populations in the temperature sensitivity
of questing, with populations from cooler climates starting questing at
lower temperatures than populations from warmer temperatures. Cool climate
populations also quest sooner when the temperature is held constant. These
patterns are consistent with local adaptation to temperature either
through direct selection or acclimation and challenge the use of fixed
thresholds for questing in modeling the spread of tick populations. Our
results also show how both time and temperature play a role in questing,
but we are unable to explain the relationship in terms of degree-time used
to model Arthropod development. We find that questing in response to
temperature fits well with a quantitative genetic model of the conditional
strategy, which reveals how selection on questing may operate and hence
may be of value in understanding the evolutionary ecology of questing.