Within species variation in host plant quality and movement behavior of Lygus rugulipennis nymphs

We studied movement behavior of the polyphagous herbivore Lygus rugulipennis Poppius (Heteroptera: Miridae) on wheat (Triticum aestivum) that had been cultivated in pots using three different levels of nitrogen fertilization. The probability of moving for fourth instar nymphs, and the time spent moving by mobile fourth and fifth instar nymphs increased with the nitrogen fertilization level of the pot. The nitrogen fertilization level of the pot did not appear to influence the probability of moving for fifth instar nymphs. The difference in movement behavior of nymphs on the pots of wheat fertilized with the lowest and the highest nitrogen levels seemed to be as great as the difference in movement behavior reported earlier on two different host plant species, viz., wheat and Tripleurospermum inodorum Schultz. The magnitude of the difference in movement behavior on the extreme nitrogen levels illustrates the importance of recognizing within species variation in plant quality when relating movement patterns of insect herbivores with host plant species.