‘Carabidologists do it all’ (Niemelä 1996a) is a phrase with which most European carabidologists are familiar. Indeed, during the last half a century, professional and amateur entomologists have contributed enormously to our understanding of the basic biology of carabid beetles. The success of the field is in no small part due to regular European Carabidologists’ Meetings, which started in 1969 in Wijster, the Netherlands, with the 14th meeting again held in the Netherlands in 2009, celebrating the 40th anniversary of the first meeting and 50 years of long-term research in the Dwingelderveld. This paper offers a subjective summary of some of the major developments in carabidology since the 1960s. Taxonomy of the family Carabidae is now reasonably established, and the application of modern taxonomic tools has brought up several surprises like elsewhere in the animal kingdom. Progress has been made on the ultimate and proximate factors of seasonality and timing of reproduction, which only exceptionally show non-seasonality. Triggers can be linked to evolutionary events and plausibly explained by the “taxon cycle” theory. Fairly little is still known about certain feeding preferences, including granivory and ants, as well as unique life history strategies, such as ectoparasitism and predation on higher taxa. The study of carabids has been instrumental in developing metapopulation theory (even if it was termed differently). Dispersal is one of the areas intensively studied, and results show an intricate interaction between walking and flying as the major mechanisms. The ecological study of carabids is still hampered by some unresolved questions about sampling and data evaluation. It is recognised that knowledge is uneven, especially concerning larvae and species in tropical areas. By their abundance and wide distribution, carabid beetles can be useful in population studies, bioindication, conservation biology and landscape ecology. Indeed, 40 years of carabidological research have provided so much data and insights, that among insects - and arguably most other terrestrial organisms - carabid beetles are one of the most worthwhile model groups for biological studies.

shrublands (Elkins et al., 1986;Lyford and Qashu, 1969;Wainwright et al., 2000), mesquite rangelands (Wood In semiarid environments, vegetation affects surface runoff either and Blackburn, 1981), and piñ on-juniper rangelands in by altering surface characteristics (e.g., surface roughness, litter absorption) or subsurface characteristics (e.g., hydraulic conductivity).the USA (Roundy et al., 1978). Similar findings have Previous observations of runoff within a piñ on-juniper [Pinus edulis been reported from other parts of the world. Examples Englem. and Juniperus monosperma (Englem.) Sarg.] woodland led are Australia, where studies were performed in both us to hypothesize that hydraulic conductivity differs between vegetamulga woodlands (Greene, 1992) and arid shrublands tion types. Using ponded and tension infiltrometers, we measured (Dunkerley, 2000a); Niger, in tiger bush (Bromley et saturated (K s ) and unsaturated [K(h )] hydraulic conductivity at three al., 1997); and Spain, in semiarid shrublands (Cerda et levels of a nested hierarchy: the patch (canopy and intercanopy), the al., 1998). In other studies, differences in infiltrability unit (juniper canopy, piñ on canopy, vegetated intercanopy, and bare have been found within the intercanopy, between areas intercanopy), and the intercanopy locus (grass, biological soil crust, exhibiting differing degrees of herbaceous cover (Wilbare spot). Differences were smaller than expected and generally not cox et al., 1988). Similarly, Wood and Blackburn (1981) significant. Canopy and intercanopy K s values were comparable with the exception of a small number of exceedingly high readings under found higher infiltration rates for mid-grass than for the juniper canopy-a difference we attribute to higher surface macro-short-grass areas. And in Spain, Cerda (1997) reported porosity beneath juniper canopies. The unsaturated hydraulic conducthat infiltration rates under the grass species Stipa tenativity, K(h ), values were higher for canopy soils than for intercanopy cissima were almost double those for adjacent bare soils, although differences were small. At the unit level, the only ground. significant differences were for K(h ) between juniper or piñ on cano-Enhanced infiltrability under vegetation canopies pies vs. bare interspaces. Median K values for vegetated intercanopy may be due to a number of factors, including textural areas were intermediate between but not significantly different from differences resulting from rain splash or trapping of those for canopies and bare areas. There were no significant differeolian sands by vegetation (Parsons et al., 1992); higher ences between grass, biological soil crust, and bare spots within the organic-matter content of the soil under vegetation; proherbaceous intercanopy area. Overall, the observed differences in K between canopy and intercanopy patches do not account for differ-tection of the soil surface by leaf litter; enhanced aggreences in runoff observed previously.

Habitat fragmentation can affect levels of herbivory in plant populations if plants and herbivores are differentially affected by fragmentation. Moreover, if herbivores are top-down controlled by predators or parasitoids, herbivory may also be affected by differential effects of fragmentation on herbivores and their natural enemies. We used natural Silene latifolia populations to examine the effects of plant population size and isolation on the level of herbivory by the seed predating noctuid Hadena bicruris and the rate of parasitism of the herbivore by its parasitoids. In addition, we examined oviposition rate, herbivory and parasitism in differently sized experimental populations. In natural populations, the level of herbivory increased and the rate of parasitism decreased with decreasing plant population size and increasing degree of isolation. The number of parasitoid species also declined with decreasing plant population size. In the experimental populations, the level of herbivory was also higher in smaller populations, in accordance with higher oviposition rates, but was not accompanied by lower rates of parasitism. Similarly, oviposition rate and herbivory, but not parasitism rate, increased near the edges of populations. These results suggests that in this system with the well dispersing herbivore H. bicruris, habitat fragmentation increases herbivory of the plant through a behavioural response of the moth that leads to higher oviposition rates in fragmented populations with a reduced population size, increased isolation and higher edge-to-interior ratio. Although the rate of parasitism and the number of parasitoid species declined with decreasing population size in the natural populations, we argue that in this system it is unlikely that this decline made a major contribution to increased herbivory.

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Four of the eight hypotheses proposed in the literature for explaining the relationship between abundance and range size (the sampling artifact, phylogenetic non-independence, range position and resource breadth hypotheses) were tested by using atlas data for carabid beetles (Coleoptera, Carabidae) from Belgium, Denmark and the Netherlands. A positive relationship between abundance and partial range size was found in all three countries, and the variation in abundance was lower for widespread species. Analysis of the data did not support three of the proposed hypotheses, but did support the resource breadth hypothesis (species having broader environmental tolerances and being able to use a wider range or resources will have higher local densities and be more widely distributed than more specialised species). Examination of species' characteristics revealed that widespread species are generally large bodied, generalists (species with wide niche breadths occurring in a variety of habitat types) and are little influenced by human-altered landscapes, while species with restricted distributions are smaller bodied, specialists (species with small niche breadths occurring in only one or two habitat types), and favour natural habitat. Landscape alteration may be an important factor influencing carabid abundance and range size in these three countries with a long history of human-induced environmental changes.

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