Summary 1.As measuring biodiversity in its entirety is impractical, there is a need for bioindicators. This study tested the hypothesis that parasitoid Hymenoptera are potential bioindicators that provide a useful means to assess the wider biodiversity of arthropod populations in agro-ecosystems. There are a range of theoretical arguments to support such a claim, including the high trophic position of these taxa within the arthropod communities in which they occur, and the unique nature of their biological relationships with the majority of terrestrial arthropod groups. 2. A survey of 48 commercial farms was conducted and Generalized Linear Models used to investigate relationships between six taxa-parasitoid Hymenoptera, Coleoptera, Hemiptera, Diptera, Araneae and plants (species richness and sward height)-in agricultural grasslands. As well as relationships between these groups, the relationship of each individual group to the overall biodiversity of all other arthropod groups was explored. 3. Both abundance (r 2 = 0AE58) and taxon richness (r 2 = 0AE54) of parasitoid Hymenoptera had stronger relationships with overall arthropod taxon richness than any other arthropod group investigated. Parasitoid abundance also had a positive relationship with species richness of Coleoptera (r 2 = 0AE23) and Hemiptera (r 2 = 0AE47).4. An historical data set demonstrated how the relationship between parasitoid abundance and overall arthropod taxon richness changes over the growing season. July, when the relationship was strongest, is potentially the most useful time to sample. 5. For use in routine monitoring, it is important that an effort be made to understand the seasonal influence on the relationship in the context being studied. Equal sampling effort must be made for all sites being compared and sites should be sampled as close together in the season as is possible. 6. Synthesis and applications. We show that, within agricultural grasslands, both the abundance and taxon richness of parasitoid Hymenoptera are more closely related with overall arthropod diversity than any other arthropod group investigated. The use of parasitoid abundance provides a simple and practicable monitoring tool for tracking change in wider arthropod diversity in agroecosystems.

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log 10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV—CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences—is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

34In the face of ongoing habitat fragmentation, species-area relationships (SARs) have 35 gained renewed interest and are increasingly used to set conservation priorities. An 36 important question is how large habitat areas need to be to optimize biodiversity 37 conservation. The relationship between area and species richness is explained by 38 colonization-extinction dynamics, whereby smaller sites harbour smaller populations, 39 which are more prone to extinction than the larger populations sustained by larger sites. 40These colonization-extinction dynamics are predicted to vary with trophic rank, habitat 41 affinity and dispersal ability of the species. However, empirical evidence for the effect of 42 these species characteristics on SARs remains inconclusive. 43In this study we used carabid beetle data from 58 calcareous grassland sites to 44 investigate how calcareous grassland area affects species richness and activity density for 45 3 species differing in trophic rank, habitat affinity and dispersal ability. In addition, we 46 investigated how SARs are affected by the availability of additional calcareous grassland 47 in the surrounding landscape. 48Our results demonstrate that beetle species richness and activity density increase 49 with calcareous grassland area for zoophagous species that are specialists for dry 50 grasslands and to a lesser extent for zoophagous habitat generalists. Phytophagous 51 species and zoophagous forest and wet grassland specialists were not affected by 52 calcareous grassland area. The dependence of species on large single sites increased with 53 decreasing dispersal ability for species already vulnerable to calcareous grassland area. 54Additional calcareous grassland in the landscape had a positive effect on local species 55 richness of both dry grassland specialists and generalists, but this effect was restricted to 56 a few hundred meters. 57Our results demonstrate that SARs are affected by trophic rank, habitat affinity 58 and dispersal ability. These species characteristics do not operate independently but 59 should be viewed in concert. In addition, species' responses depend on the landscape 60 context. Our study suggests that the impact of habitat area on trophic interactions may be 61 larger than previously anticipated. In small habitat fragments surrounded by a hostile 62 matrix, food chains may be strongly disrupted. This highlights the need to conserve 63 continuous calcareous grassland patches of at least several hectares in size. 64 65

1. Field margins within intensively managed ecosystems are often seen as a last refuge for biodiversity, and are typically targeted with measures within many agri-environment schemes. Grassland accounts for 81 million ha of land within the EU; however, the ecology of field margins associated with permanent grassland has not been well studied.2. This study investigated the effects of experimental field margin measures on hymenopteran parasitoid communities over a 5-year period. Hymenopteran parasitoids were chosen because they occupy high trophic levels, feed on a diverse range of plant and invertebrate hosts, and are considered good indicators of arthropod diversity. Establishment methods included: fencing, natural regeneration, and reseeding with a wildflower mixture, at three margin widths.3. Field margin establishment method had a significant effect on abundance of parasitoids. Establishment method did not have a significant effect on parasitoid genera diversity, but did affect parasitoid community composition. Margin width had no significant impact on parasitoid communities. 4. Grazing had a significant negative effect on parasitoid genus richness and community structure. This suggests that structural diversity of vegetation plays an important role in parasitoid community structure.5. Plant species richness did not significantly affect parasitoid abundance or genera richness. Noxious species within plots resulted in a significantly greater abundance and diversity of parasitoids and of idiobionts in particular.6. Where plant species richness is limited, simple measures such as fencing of narrow field margins may be as effective at increasing parasitoid taxon richness and abundance (indicators of arthropod richness and abundance) as expensive measures such as reseeding and wider margin widths.

Severe declines in biodiversity have been well documented for many taxonomic groups due to intensification of agricultural practices. Establishment and appropriate management of arable field margins can improve the diversity and abundance of invertebrate groups; however, there is much less research on field margins within grassland systems. Three grassland field margin treatments (fencing off the existing vegetation “fenced”; fencing with rotavation and natural regeneration “rotavated” and; fencing with rotavation and seeding “seeded”) were compared to a grazed control in the adjacent intensively managed pasture. Invertebrates were sampled using emergence traps to investigate species breeding and overwintering within the margins. Using a manipulation experiment, we tested whether the removal of grazing pressure and nutrient inputs would increase the abundance and richness of breeding invertebrates within grassland field margins. We also tested whether field margin establishment treatments, with their different vegetation communities, would change the abundance and richness of breeding invertebrates in the field margins. Exclusion of grazing and nutrient inputs led to increased abundance and richness in nearly all invertebrate groups that we sampled. However, there were more complex effects of field margin establishment treatment on the abundance and richness of invertebrate taxa. Each of the three establishment treatments supported a distinct invertebrate community. The removal of grazing from grassland field margins provided a greater range of overwintering/breeding habitat for invertebrates. We demonstrate the capacity of field margin establishment to increase the abundance and richness in nearly all invertebrate groups in study plots that were located on previously more depauperate areas of intensively managed grassland. These results from grassland field margins provide evidence to support practical actions that can inform Greening (Pillar 1) and agri‐environment measures (Pillar 2) of the Common Agricultural Policy (CAP). Before implementing specific management regimes, the conservation aims of agri‐environment measures should be clarified by defining the target species or taxonomic groups.

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The insects are the most diverse organisms on this planet and play an essential role in ecosystem functioning, yet we know very little about them. In light of the Convention on Biological Diversity, this paper summarises the known insect species numbers for Ireland and questions whether this is a true refl ection of our insect diversity. The total number of known species for Ireland is 11,422. Using species accumulation curves and a comparison with the British fauna, this study shows that the Irish list is incomplete and that the actual species number is much higher. However, even with a reasonable knowledge of the species in Ireland, insects are such speciose, small, and inconspicuous animals that it is diffi cult to assess species loss. It is impossible to know at one point in time the number of insect species in Ireland and, although it is useful to summarise the known number of species, it is essential that biodiversity indicators, such as the Red List Index, are developed.

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