Activity pattern and thermal biology of a day‐flying hawkmoth (Macroglossum stellatarum) under Mediterranean summer conditions

The daily activity pattern and aspects of the thermal biology are described for the day‐flying hawkmoth, Macroglossum stellatarum L. (Lepidoptera: Sphingidae), while foraging at a flowering population of Lavandula latifolia (Labiatae) under the dry‐hot summer conditions of a southeastern Spanish locality. The average abundance of M.stellatarum remained fairly constant from sunrise to about 17.00 hours (GMT), and a distinct peak occurred in the evening (18.00—20.00 hours). Foraging took place over a broad range of microclimatic conditions, as described by air temperature ( T a ; range 19‐36°C) and solar radiation (IR; range 1–1025 Wm ‐2 ). The thoracic temperature ( T th ) of insects remained within relatively narrow limits (39–46°C), with the highest values occurring around noon. Variation in T th mainly reflected differences in T a between foraging sites and times. T th was nonlinearly related to T a , the rate of increase of T th with T a decreasing with increasing T a . The unusual tolerance of high T th exhibited by M.stellatarum , and its enhanced thermoregulatory capacity at high T a , enable this species to withstand the severe environmental conditions faced during diurnal foraging in the Mediterranean summer.