Ecography (1998) 21, 289-296

Jane K. Hill, Keith C. Hamer and Ian D. Hodkinson (1998)
Variation in resource exploitation along an altitudinal gradient: the willow psyllids (Cacopsylla spp.) on Salix lapponum
Ecography 21 (3), 289-296
Abstract: Three congeneric species of Salix-fedding psyllid Cacopsylla spp. Occur along an altitudinal gradient (988 1222 m. a.s.l.) in southern Norway. The 27-km transect covered the local altitudinal range of the three species. Each species showed a different characteristic altitudinal distribution: C. propinqua occurred over the entire altitudinal range of the transect C. palmeni was restricted to higher altitude and C. brunneipennis occurred mainly at lower altitudes. This pattern of local altitudinal distribution mirrored the broader geographical distributions of these psyllids along latitudinal gradients. All three species developed on willow catkins, but also made use of leaves. Species differed in their use of leaves with >10% of sampled individuals of C. brunneipennis or C. palmeni developing on leaves compared with up to 80% in C. propinqua. The proportion of C. propinqua nymphs developing on catkins increased with altitude and was also related to the temporal and spatial availability of catkins but was not a result of competitive displacement from catkins. Nitrogen concentration of host plants did not affect the proportions of C. propinqua on leaves or catkins and was not related to adult size or psyllid density on catkins. Patterns or resource use are discussed in relation to differences in the distribution and abundance of the three species along the transect.
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Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cacopsylla (genus)	Willow (Salix)