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The leafhoppers, planthoppers and their allies (collectively known as the Auchenorrhyncha) are presented as a group of insects that are highly appropriate for studying grassland ecology and conservation, evaluating the conservation status of sites and monitoring environmental and habitat change. Semi-natural grasslands typically support dense populations and a wide range of species with diverse ecological strategies. Their numerical dominance in many grasslands means that they have considerable functional significance, both as herbivores and as prey for higher trophic levels. Population and assemblage studies are supported by good ecological knowledge about most species and modern identification keys. Hitherto, most studies have focused on the composition and structure of assemblages and how they are affected by conservation management. However, grasslands support many rare species with small and fragmented populations which deserve conservation attention in their own right, and recent work has started to reflect this. The effects of management on the composition and structure of grassland leafhopper populations and assemblages are described and an assessment is given of the main threats facing individual species and overall diversity. There is a need to synthesise the scattered literature on grassland leafhoppers, to provide a model for how the composition and structure of populations and assemblages respond to major environmental and anthropogenic gradients across large biogeographic areas. Such an analysis could help predict the impact of likely future changes in land use and climate.

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Aim This paper tests firstly for the existence of a general relationship between body size of terrestrial animals and their incidence across habitat patches of increasing size, and secondly for differences in this relationship between insects and vertebrates. Location The analysis was based on the occupancy pattern of 50 species from 15 different landscapes in a variety of ecosystems ranging from Central European grassland to Asian tropical forest. Methods The area‐occupancy relationship was described by incidence functions that were calculated using logistic regression. A correlation analysis between body size of the species and the patch area referring to the two given points of the incidence function was performed. In order to test for an effect of taxon (insects vs. vertebrates), an analysis of covariance was conducted. Results In all species, the incidence was found to increase with increasing patch area. The macroecological analysis showed a significant relationship between the incidence in habitat patches and the body size of terrestrial animals. The area requirement was found to increase linearly with increasing body size on a log‐log scale. This relationship did not differ significantly between insects and vertebrates. Conclusions The approach highlighted in this paper is to associate incidence functions with body size. The results suggest that body size is a general but rather rough predictor for the area requirements of animals. The relationship seems valid for a wide range of body sizes of terrestrial animals. However, further studies including isolation of habitats as well as additional species traits into the macroecological analysis of incidence functions are needed.

Abstract. The nymphs of spittlebugs (Hemiptera, Cercopidae) are xylem-feeders and live on herbs, grasses or woody plants within their self-produced spittle masses. Nymphs of the spittlebug Neophilaenus albipennis live aggregated in these spittle masses on their host plant Brachypodium pinnatum, a common grass in dry grassland. The objective of this study was to estimate nymphal mortality rates and to examine what role aggregation and vegetation structure play in the mortality of the nymphs. The aggregation and mor tality were measured using two different methods, direct monitoring and caging of nymphs. The nymphs passively aggregated with up to 4 nymphs per spittle and aggregation decreased with instar. The aggregation of the nymphs resulted in a reduced mortality in all instars. Although it has already been argued that aggregation may be an advantage, this study is the first direct evidence (i.e. direct measurement of single individuals) for the benefit of aggregation to individual spittlebug nymphs. Despite a clumped distribu tion of N. albipennis nymphs in tall vegetation, nymphal mortality was not correlated with vegetation height.

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Biedermann, R. 2004. Modelling the spatial dynamics and persistence of the leaf beetle Gonioctena olivacea in dynamic habitats. Á/ Oikos 107: 645 Á/653.In dynamic landscapes natural and anthropogenic disturbance as well as succession are responsible for the emergence and subsequent disappearance of suitable habitat patches. Species inhabiting such landscapes are faced with varying number and spatial configuration of patches. A stochastic, spatially explicit simulation model was developed in order to analyse the persistence of the leaf beetle Gonioctena olivacea in a system of dynamic patches of its host plant Cytisus scoparius. The model was parameterized with data from a three-year field study on the spatial configuration, distribution, and turnover of the host plant patches as well as the patch occupancy, extinction, and colonization rates of the beetle. The simulations showed large fluctuations in the occurrence of the beetle in the patches. High levels of occupancy were related to high aggregation of the patches within the landscape. The velocity of patch turnover was found to have a severe effect on the persistence of the beetle metapopulation. Enhancing the turnover rate by only a few patches, the mean time to extinction decreases rapidly. Moreover, the results revealed that not necessarily an effect of connectivity can be detected in the analysis of occupancy patterns in dynamic landscapes, although the colonization of patches is clearly connectivity-dependent. In general, this modelling study demonstrates the importance of detailed information on patch turnover. The amount and spatial distribution of suitable habitat is a major driver of metapopulation dynamics of species in dynamic landscapes.