The distribution, abundance and host plant relationships of feeding psyllids (Homoptera: Psylloidea) in arctic Alaska.

1. Five species of psyllid occurred on seven species of at Meade River, Alaska. Studies were made on the two common species Löw and Hodkinson. The former feeds on the phanerophy tes and , the latter on the chamaephytes and 2. Both and had a 1-year life cycle and nymphal development took place on the female catkin. The life cycle was generally closely synchronized with the period of catkin development. However, only a few eggs were laid on 3. Seasonal perturbation of the host plant by flooding, ice movement and blown sand prevented psyllids breeding in certain areas colonized by the host plant. 4. In densities and 'feeding pressure', measured as biomass of psyllids per gram of catkin, on the different host plants followed the sequence In densities and feeding intensities were similar onandand grazing intensity was comparable withon 5. A highly significant negative correlation was found between psyllid density and catkin dry weight in and , suggesting that psyllid feeding is affecting catkin growth. 6. Predation of psyllid nymphs by syrphid larvae was heavy but there was no evidence of parasitism. 7. The life history strategies of the five psyllid species are discussed within the context of the constraints imposed by the arctic environment.