Within-patch search flights by Pachyneuron aphidis (Hym, Pteromalidae): a potential strategy to compensate reduced foraging speed by foot

Search flights of the aphid hyperparasitoid Pachyneuron aphidis were observ ed under field conditions. The pattern and duration differed from those des cribed for aphid primary parasitoids. Forty per cent targeted landings clos e to aphid colonies indicate that P. aphidis females locate potential host sites during slow and extraordinary long flights in the host plant Cirsium arvense. A comparison between different aphid hyperparasitoids showed that the walking speed of P. aphidis was significantly slower than that of other polyphagous species. This suggests that search flights were performed in o rder to compensate for a reduced efficiency of foraging on foot.