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•1. Hedgerows provide habitat, shelter and resources for many species including functionally important taxa and threatened species. Hedgerows store carbon both above- and below-ground and provide a range of other ecosystem services. Policies incentivizing increases in the extent and quality of hedgerows require evidence to determine how these increases may best support a wide range of taxa and to improve hedgerow habitat quality. •2. Here, available evidence for increasing hedgerow extent and improving their quality is discussed in the context of current conservation policy. Moderate evidence supports a substantial increase in average hedgerow extent from 4.2 km/km2 to around 10 km/km2 in the United Kingdom, to optimize support for many wildlife taxa, habitat connectivity and carbon storage. •3. Evidence also supports the development of wider and structurally denser hedges with more diverse structures and management approaches, and hedgerow networks that are well connected with each other and with other semi-natural habitats. •4. However, barriers may hinder the implementation of hedgerow policies, and there remain substantive gaps in the evidence base. Knowledge gaps include the current quality or condition of UK hedges, understanding in which landscape contexts new hedges would best be planted to support biodiversity, the role of hedgerows in connectivity as species' ranges change under a future climate, and whether an increase in hedgerow extent might increase the spread of invasive species, tree pests or diseases. •5. These gaps must be filled if conservation policies, including future agri-environment schemes, are to ensure that hedgerows reach their considerable potential in aiding nature's recovery and addressing climate change.

Editorial.

Abiotic stresses such as drought and nutrient availability can affect invertebrate herbivores feeding on plants, and potentially cascade up to impact their predators and parasitoids. Although these two factors separately been the subject of many studies, there are few tests of their combined effects in the context of pest species and their natural enemies on cultivated plants. Climate change models predict an increase in the frequency and severity of droughts, while the type and amount of fertiliser applied to crops is more under the control of growers. Understanding how these two abiotic factors may interact is key to utilising the potential of natural enemies to control pests under a future climate. To address this, a range of drought and fertiliser type treatments were applied to a model Brassica system in a factorial design, and the performance of two ubiquitous aphid species and their parasitoids was assessed. One aphid species was a specialist on Brassicas (Brevicoryne brassicae, with parasitoid Diaeretiella rapae) and the second a generalist aphid species (Myzus persicae, with parasitoid Aphidius colemani). The performance of both aphid species responded in a similar way to the treatments, and was maximised on plants growing in organic fertilisers under medium levels of drought stress. The strongest effects of drought and fertiliser cascaded up to affect parasitoids. Parasitoid performance responded in a broadly similar way to their aphid host performance in relation to fertiliser type. Some of the smaller effects of fertiliser treatments on aphid performance were not found for parasitoid performance. Aphid performance was greatest on plants under medium drought stress, but the parasitoids only responded consistently to the high drought stress treatment, on which their performance was reduced. Interactions between the drought and fertiliser did not have a large effect on aphid or parasitoid performance, compared with the strong main effects found for each tre

An output of Natural England’s Defining Favourable Conservation Status (DFCS) project. Hedgerows are a widespread Priority Habitat (i.e. a habitat of principal importance for biodiversity conservation), providing key semi-natural habitat for a broad range of biodiversity, including many threatened species. They occur predominantly in lowland farmland but also in urban areas. The distribution of hedgerows reflects historic and current agricultural and social practices, and underlying biophysical variables. Hedgerows are largely man-made features, which historically were created through the planting of woody species for the specific purpose of dividing up rural land and preventing the movement of stock between land parcels. In urban areas, hedgerows have mainly been planted to create boundaries between properties, for aesthetic or wildlife reasons within gardens and parks. The length of hedgerows in England needs to increase substantially in order to support thriving biodiversity and to achieve Favourable Conservation Status (FCS). There is a moderate amount of evidence supporting the recommended level of increase in hedgerow, but the evidence that is available overwhelmingly supports an increase in length for a range of taxa. Overall confidence in an increase in hedgerow length being required is high. Higher average density of hedgerows (in suitable habitats) due to increased length will result in improvements in the provision of hedgerow habitat for wildlife and in landscape connectivity. The use of hedgerows by mobile species for daily movement (e.g. foraging) is well supported by available evidence, across a range of taxa. There is less evidence for the role of hedgerows for population dispersal or migration, despite their strong potential to support connectivity and the likely importance of this in the context of climate change. Since hedgerows consist primarily of shrubs and trees, their distribution is associated with that of shrubby and/or woodland habitats. T

Hedgerow plant communities, including herbaceous species growing in the hedge base, are important conservation indicators of hedgerow habitat condition. The effects of management have the potential to alter the species richness and composition of hedgerow plant communities, but this has not previously been tested experimentally. A novel field experiment was used to test the effects of hedgerow management on hedgerow basal flora. Hedgerow cutting treatments, including relaxed cutting regimes funded under agri-environment schemes, were applied in replicated blocks at four sites in lowland UK. After six years of experimental cutting treatments the hedgerow plant communities were surveyed, both directly under the woody hedgerow vegetation and immediately adjacent to the hedges. For hedgerow plots cut in autumn, a reduced intensity cutting regime (incremental cutting) resulted in an average reduction of one species and a small shift towards plants typical of less fertile conditions, compared to cutting back to a standard height and width. Hedgerow plots cut in late winter had a plant community typical of slightly shadier conditions, compared with those cut in autumn. Hedgerow cutting management can thus alter the richness and composition of plant communities, over relatively short timescales. These results are discussed in the context of longer term trends in hedgerow plant communities across northern Europe, and conservation management funded under agri-environment schemes.

Hedgerows are a key semi-natural habitat in intensively farmed landscapes, and their roles in providing food and nesting resources, shelter, corridors and habitat niches for wildlife are closely linked to their management. Here, we review recent research into cutting and rejuvenation hedgerow management practices and summarise how these affect plant and invertebrate taxa, including those that are priorities for conservation and functionally important as providers of ecosystem services. Studies demonstrating the role of hedgerows in connecting semi-natural habitats and the way in which this can be shaped by management are also reviewed. The role and efficacy of conservation policy in improving the value of hedgerows for wildlife, through agri-environment schemes, is examined in the context of the evidence reviewed for the benefits of different types of hedgerow management.

1. The Brown hairstreak butterfly has declined in range and abundance over the past 50 years, leading to designated conservation status in several European countries including England and Wales. The Brown hairstreak's decline has been linked to changes in hedgerow management, based on mortality of eggs over winter and female oviposition preferences. 2. We assessed Brown hairstreak egg abundance in late winter over 4 years in response to hedgerow management treatments to manipulate the frequency, timing, and the intensity of trimming (reduced intensity resulting in an annual increase of approximately 10 cm in hedge height and width), using a field experiment with a randomised block design. 3. Hedgerow plots cut every year to a standard height and width had the lowest Brown hairstreak egg abundance; this is the most common hedgerow management outside agri-environment schemes (AES). Cutting hedgerow plots at a reduced intensity nearly doubled the number of surviving eggs in late winter. Plots cut at a reduced frequency in autumn (once every 3 years), which forms part of current English AES, had 1.3 times more eggs than those cut annually. 4. Current AES management prescriptions are likely to benefit the Brown hairstreak, but its requirements need to be balanced with those of other taxa in relation to the timing of hedgerow cutting. Cutting hedges at a reduced intensity has previously been shown to benefit the wider Lepidoptera community as well as Brown hairstreak butterflies. Reduced intensity cutting does not currently form part of AES hedgerow prescriptions, but could be considered for inclusion in future schemes.

This chapter summarises key aboveground-belowground interactions between invertebrates and focuses on aboveground-belowground herbivore interactions. It considers how these may be changed by elevated carbon dioxide (e[CO2]), operating alone and in tandem with increased air temperatures, and altered precipitation patterns. It is clear that climate and atmospheric change have the capacity to modify aboveground-belowground invertebrate interactions, with altered patterns of precipitation seemingly being the most influential. Increases in temperature are likely to affect aboveground invertebrates much more than belowground invertebrates, since the latter are buffered from temperature changes to a greater extent. The impacts of e[CO2] on aboveground arthropods are relatively well characterised, but comparatively less is known about the responses of belowground invertebrates. The chapter describes a series of experiments that explored the impacts of predicted rainfall patterns on the interactions between belowground herbivores, aboveground herbivores and natural enemies of the aboveground herbivores.

1. Arthropod assemblages form a fundamental part of terrestrial ecosystems, underpinning ecosystem processes and services. Yet, little is known about how invertebrate communities, as a whole, respond to climatic and atmospheric changes, including predicted increases in carbon dioxide concentrations (CO2). 2. To date, woodland Free Air CO2 Enrichment (FACE) studies have focused entirely on northern hemisphere managed plantations. We manipulated atmospheric CO2 in a mature, native Eucalyptus woodland (0.15 ha, >32 000 m3) in Australia, using the Eucalyptus FACE (‘EucFACE’) facility. We used three complementary sampling methods (vacuum sampling, pitfall and sticky trapping) to record invertebrate abundances under ambient and elevated levels of CO2 (400 versus 550 ppm). 3. Based on the collection of over 83 000 invertebrates, we found significant declines in the overall abundance of ground-dwelling (14.7%) and aerial (12.9%) arthropods under elevated CO2, with significant decreases in herbivore, omnivore, scavenger and parasitoid functional groups. Even though several groups showed varying declines in abundance, elevated CO2 did not measurably affect community composition. 4. The results of the present study indicate that atmospheric CO2 levels predicted within the next 35 years may cause declines in arthropod abundances in Eucalyptus woodland. Declines found in several functional groups suggest that elevated atmospheric CO2 has the potential to affect ecosystem processes, possibly including nutrient cycling by herbivores and omnivores, as well as biocontrol by parasitoids.

Hedgerows are a key semi-natural habitat for biodiversity in intensive agricultural landscapes across northern Europe and support a large invertebrate fauna. Management can have large effects on the value of hedgerows as a wildlife habitat, thus sensitive management is incentivised through agri-environment schemes (AES). We tested how current and potential future AES hedge management regimes affected the diversity and abundance of Lepidoptera species that utilise the hedge as a breeding resource, using a long term, multi-site, manipulative field experiment. Hedgerow management in some current AES options (reduced trimming frequency and cutting in winter) increased Lepidoptera abundance and the diversity of components of the Lepidoptera community linked with specific lifecycle traits. However, the most frequently applied hedgerow AES option currently applied in the UK (cutting once every 2 years in autumn) did not benefit Lepidoptera compared to standard hedgerow management outside AES (annual trimming in autumn). Decreasing the intensity of hedgerow trimming improves the diversity of the whole Lepidoptera assemblage, and should be considered as part of biodiversity conservation in farmed landscapes.

Hedgerows are an important semi-natural habitat for invertebrates and other wildlife within agricultural landscapes. Hedgerow quality can be greatly affected either by over- or under-management. Neglect of hedgerows is an increasingly important issue as traditional management techniques such as hedgelaying become economically unviable. In the UK, funding for hedge management is available under agri-environment schemes but relatively little is known about how this impacts on wider biodiversity. We used a randomised block experiment to investigate how habitat structural change, arising from a range of techniques to rejuvenate hedgerows (including more economic/mechanised alternatives to traditional hedgelaying), affected invertebrate abundance and diversity. We combined digital image analysis with estimates of foliage biomass and quality to show which aspects of hedge structure were most affected by the rejuvenation treatments. All investigated aspects of habitat structure varied considerably with management type, though the abundance of herbivores and predators was affected primarily by foliage density. Detritivore abundance was most strongly correlated with variation in hedge gap size. The results suggest that habitat structure is an important organising force in invertebrate community interactions and that management technique may affect trophic groups differently. Specifically we find that alternative methods of hedgerow rejuvenation could support abundances of invertebrates comparable or even higher than traditional hedgelaying, with positive implications for the restoration of a larger area of hedgerow habitat on a limited budget.

Hedgerows provide key wildlife habitat in intensive agricultural landscapes, but are declining in length and structural condition due to a lack of rejuvenation management, neglect and over-frequent trimming with mechanised flails. Here, we test cheaper, alternative methods to traditional hedge laying methods using a multi-site manipulative field experiment. In the first quantitative test of new approaches to hedge rejuvenation management, hedge regrowth, structure, berry provision for over-wintering wildlife and cost of rejuvenation were assessed in response to five methods, for three years following rejuvenation. Three ‘laying’ methods and coppicing were effective at improving hedgerow condition by stimulating basal regrowth, thus increasing the density of woody material at the base and reducing gap size. The pros and cons of coppicing are discussed in relation to its impact on different wildlife groups, and it is recommended in limited circumstances. Differences between the three ‘laying’ methods reduced over time, so a cheaper conservation hedging method is recommended as an alternative to traditional hedge laying. This new approach to hedge management offers the potential to restore twice the length of hedgerow currently rejuvenated under agri-environment schemes.

Gaining a better understanding of climate and atmospheric change effects on species interactions is one of the great challenges facing modern ecology.Here, we review the literature concerning the responses of insect herbivores and their natural enemies to atmospheric and climate change, focusing specifically on elevated concentrations of atmospheric CO2 and air temperatures.We recommend that future work on the responses of systems to climate change incorporates as far as possible the trophic complexity inherent in ecosystems, and where feasible, considers the effects of interrelated climate factors in tandem. Such studies will produce more realistic insights into how species interactions may respond under future climates.

1. Hedgerows provide an important habitat for wildlife including invertebrates, representing a large proportion of semi-natural habitat patches in the modern agricultural landscapes of the UK and Europe. Around 40% of hedgerow length in England is managed under agri-environment scheme (AES) options, which specify less frequent cutting and advise cutting in winter. 2. Hedgerow management can alter habitat structure and quality, potentially influencing invertebrate community structure. We assessed the impacts of management treatments on moth communities and their parasitoids. Two treatments (‘cutting frequency’: once every 1, 2, or 3 years, and ‘cutting time’: autumn vs. winter) were applied to a long-running hedgerow experiment, mimicking AES prescriptions. Moth larvae were collected from the hedgerows, identified and reared to determine parasitism. Hedgerow structure and foliar quality were quantified and related to changes in moth abundance, diversity, species richness, and parasitism. 3. Hedgerow management did not significantly affect overall abundance of moth larvae, but did affect the abundance of certain feeding guilds and trophic interactions with parasitoids. Concealed moth larvae (mining, tentiform, and case bearing) were more abundant on hedgerows cut infrequently (every 2 or 3 years vs. annually). Parasitism rates were higher on hedgerows cut less often, when these were cut in autumn. There was a strong trend towards greater moth species richness and diversity on winter cut hedgerows. 4. Agri-environment scheme management can thus have complex effects on invertebrate communities. The abundance of some moths may be positively affected by AES hedgerow management and this can have knock-on effects on parasitoid abundance.

Multitrophic interactions are likely to be altered by climate change but there is little empirical evidence relating the responses of herbivores and parasitoids to abiotic factors. Here we investigated the effects of drought on an above/belowground system comprising a generalist and a specialist aphid species (foliar herbivores), their parasitoids, and a dipteran species (root herbivore).We tested the hypotheses that: (1) high levels of drought stress and below-ground herbivory interact to reduce the performance of parasitoids developing in aphids; (2) drought stress and root herbivory change the profile of volatile organic chemicals (VOCs) emitted by the host plant; (3) parasitoids avoid ovipositing in aphids feeding on plants under drought stress and root herbivory. We examined the effect of drought, with and without root herbivory, on the olfactory response of parasitoids (preference), plant volatile emissions, parasitism success (performance), and the effect of drought on root herbivory. Under drought, percentage parasitism of aphids was reduced by about 40–55% compared with well watered plants. There was a significant interaction between drought and root herbivory on the efficacy of the two parasitoid species, drought stress partially reversing the negative effect of root herbivory on percent parasitism. In the absence of drought, root herbivory significantly reduced the performance (e.g. fecundity) of both parasitoid species developing in foliar herbivores. Plant emissions of VOCs were reduced by drought and root herbivores, and in olfactometer experiments parasitoids preferred the odour from well-watered plants compared with other treatments. The present work demonstrates that drought stress can change the outcome of interactions between herbivores feeding above- and belowground and their parasitoids, mediated by changes in the chemical signals from plants to parasitoids. This provides a new insight into how the structure of terrestrial communities may be aff

Hedgerows provide key habitat and refuges for wildlife in otherwise intensively-managed landscapes, and may play a role in connecting increasingly fragmented habitats. However, the processes governing changes to the floral biodiversity of hedges are poorly understood. We analysed a unique, long-term data set of plant species richness over a 70 year period at 357 hedgerow sites in southern England to quantify changes in a, b and c diversity, and identify the role of hedge management and other possible drivers of change. Alpha diversity increased in hedgerows, while a reduction in b diversity was indicated by taxonomic homogenisation, whereby previously distinct communities of species become more similar to one another over time. Changes in the regional species pool (c diversity) differed with plant life-history; it increased for woody species but decreased among herbaceous hedge species. Hedgerow communities shifted towards species associated with higher soil fertility, a more competitive ecological strategy and, in unmanaged hedgerows, greater shade tolerance. Probable drivers for these changes include the move from traditional forms of management such as coppicing and hedge-laying towards either no management or frequent cutting with a mechanical flail, and eutrophication. The extent of changes in plant diversity over time was determined by both historical and recent hedgerow management, but these management effects varied with plant life-history attributes. However, changes in hedge quality and floral diversity were not linked directly to a 60% increase in the proportion of land use categories classified as ‘intensive’ adjacent to the sites over the 70 years. Recommendations are made for future hedgerow management based on conservation objectives for specific groups of hedge plant species.

1. Sustainable and conventional farming systems use fertilizers that differ in the availability of nitrogen, which may affect plant quality to alter the abundance and performance of potential pest species. 2. We grew brassica plants in several types of fertilizer, including those commonly used in conventional and sustainable farming systems, and an unfertilized control. The effects of fertilizer type on the performance of two phid species and foliar glucosinolate content were investigated. 3. Both aphid species performed poorly (with reduced fecundity) on the unfertilized treatment compared with those feeding on fertilized host plants. 4. Brevicoryne brassicae, the brassica specialist, performed best on Brassica oleracea plants fertilized with an organic animal manure, with a 72% increase in fecundity and an 18% increase in intrinsic rate of increase compared with plants fertilized with ammonium nitrate. 5. By contrast, the generalist Myzus persicae had an intrinsic rate of increase that was reduced by 15% on plants growing in the animal manure compared with those growing in ammonium nitrate. 6. These results may explain earlier findings on the effects of fertilizer type on aphid populations in the field, and are discussed in the context of pest species’ responses to sustainable and conventional agricultural systems.

1. The plant stress, plant vigour and pulsed stress hypotheses describe the relationships between drought stress, plant quality and herbivore performance. We used an aphid- Brassica system to test these hypotheses under different drought treatments. 2. The quantity of water added per plant/week was 75%, 50% and 25% of the control (unstressed) water regime for low, medium and high drought stress, respectively, and 50% applied fortnightly for pulsed drought stress. The performance of a ‘senescence’ (generalist) and a ‘flush’ feeder (specialist) aphid species and host plant quality were assessed. 3. Drought treatments had a similar effect on the fecundity and intrinsic rate of increase of both aphid species. Aphid perforance on unstressed and highly drought-stressed plants was significantly lower compared with medium drought stress. On average, 20% greater fecundity and 40% greater intrinsic rates of increase were recorded for both aphid species at medium drought stress compared with unstressed plants. 4. Plant biomass and relative water contents were significantly greater for unstressed plants compared with high and pulsed drought treatments. Foliar nitrogen concentration was significantly greater in the high drought stress and pulsed treatments, and the dominant glucosinolate (glucobrassicin) concentration was significantly greater in drought stress treatments. 5. The present study supports the plant stress hypothesis, although the plant vigour and pulsed stress hypotheses are not supported by our data. The implications of these findings for plant–herbivore interactions under changing environmental conditions are discussed.

Hedgerows provide important habitat and food resources for overwintering birds, mammals and invertebrates. Currently, 41% of managed hedgerow length in England forms part of three Agri-Environment Scheme (AES) options, which specify a reduction in hedgerow cutting frequency from the most common practice of annual cutting. These AES options aim to increase the availability of flowers and berries for wildlife, but there has been little rigorous testing of their efficacy or estimates of the magnitude of their effects. We conducted a factorial experiment on hawthorn hedges to test the effects of (i) cutting frequency (every 1, 2 or 3 years) and (ii) timing of cutting (autumn vs. winter) on the abundance of flowers and berry resources. Results from 5 years show that hedgerow cutting reduced the number of flowers by up to 75% and the biomass of berries available over winter by up to 83% compared to monitored uncut hedges. Reducing cutting frequency from every year to every 3 years resulted in 2.1 times more flowers and a 3.4 times greater berry mass over 5 years. Cutting every 2 years had an intermediate effect on flower and berry abundance, but the increase in biomass of berries depended on cutting in winter rather than autumn. The most popular AES option is cutting every 2 years (32% of English managed hedgerow length). If these hedges were managed under a 3 year cutting regime instead, we estimate that biomass of berries would increase by about 40%, resulting in a substantial benefit for wildlife.

The hypothesis that plants supplied with organic fertilizers are better defended against insect herbivores than those supplied with synthetic fertilizers was tested over two field seasons. Organic and synthetic fertilizer treatments at two nitrogen concentrations were supplied to Brassica plants, and their effects on the abundance of herbivore species and plant chemistry were assessed. The organic treatments also differed in fertilizer type: a green manure was used for the low-nitrogen treatment, while the high-nitrogen treatment contained green and animal manures. Two aphid species showed different responses to fertilizers: the Brassica specialist Brevicoryne brassicae was more abundant on organically fertilized plants, while the generalist Myzus persicae had higher populations on synthetically fertilized plants. The diamondback moth Plutella xylostella (a crucifer specialist) was more abundant on synthetically fertilized plants and preferred to oviposit on these plants. Glucosinolate concentrations were up to three times greater on plants grown in the organic treatments, while foliar nitrogen was maximized on plants under the higher of the synthetic fertilizer treatments. The varying response of herbivore species to these strong differences in plant chemistry demonstrates that hypotheses on defence in organically grown crops have over-simplified the response of phytophagous insects.

Root herbivores can have a positive or negative effect on the abundance and/or performance of foliar phytophages. In addition, abiotic factors such as drought can either strengthen or weaken this effect, depending on the system under investigation. One explanation for these varying responses lies in differences in the physiological response of host plants to drought and root herbivores. Here, the impacts of root phytophages on a leaf-mining species feeding on annual and perennial plant species (four Sonchus species) were compared. The responses of plants and leaf-miners to drought and root herbivore treatments were not related to whether the host plant was an annual or perennial. However, where root feeders did affect foliar phytophage performance, this occurred only under a drought treatment, demonstrating the potential for climate change to alter the outcome of plant-mediated interactions.

Summer droughts are predicted to increase in severity and frequency in the United Kingdom, due to climate change. Few studies have addressed the impacts of drought on interactions between species, and the majority have focussed on increases in CO2 concentration and changes in temperature. Here, the effect of experimental summer drought on the strength of the plant-mediated interaction between leaf-mining Stephensia brunnichella larvae and root-chewing Agriotes larvae was investigated. Agriotes larvae reduced the abundance and performance of S. brunnichella feeding on a mutual host plant, Clinopodium vulgare, as well as the rate of parasitism of the leaf-miner. The interaction did not, however, occur on plants subjected to a severe drought treatment, which were reduced in size. Changes to summer rainfall, due to climate change, may therefore reduce the occurrence of plant-mediated interactions between insect herbivores.

Soil invertebrate communities are likely to be highly vulnerable to low soil moisture, caused by a reduction in summer rainfall which is predicted for some regions under current climate change scenarios. However, the effects of changes in summer rainfall on soil invertebrate assemblages have rarely been tested experimentally. In this study, samples were taken in 2003 and 2004 from a long-running field experiment, to investigate the impact of 10 years of experimental summer drought and increased summer rainfall manipulations on the soil fauna of a calcareous grassland. Summer drought altered the soil invertebrate assemblage in the autumn, immediately following treatment application, but by the following spring treatment effects were no longer apparent. The two most common root herbivore species responded differently to the summer rainfall manipulations. Larvae of the dominant root-chewing species, Agriotes lineatus, were more numerous under enhanced rainfall in both the spring and autumn. In contrast, abundance of the Coccoidea Lecanopsis formicarum was unaffected by the rainfall manipulations. The responses of root herbivores to an increased incidence of summer droughts are therefore likely to vary, depending on their feeding strategy and life history.

The impact of climate change on phytophages is difficult to predict, due in part to variation between species in their responses to factors such as drought stress. Here, the hypothesis that several species within the leaf-mining feeding guild will respond in a consistent way to changes in rainfall patterns is tested, using a manipulative field experiment. Summer drought, enhanced summer rainfall, and control treatments were imposed on a calcareous grassland community, and the responses of five leaf-mining species were assessed. One leaf-mining species was more abundant under enhanced rainfall, one was more abundant under drought, and the other three species showed no consistent response to the rainfall treatments. Higher parasitism levels under drought may partly explain the response of one species (Stephensia brunnichella) to the treatments. These results show that generalisations relating to drought stress impacts cannot be drawn at the feeding guild level for leaf-mining insects.