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Each year, trillions of insects make long-range seasonal migrations. These movements are relatively well understood at a population level, but how individual insects achieve them remains elusive. Behavioral responses to conditions en route are little studied, primarily owing to the challenges of tracking individual insects. Using a light aircraft and individual radio tracking, we show that nocturnally migrating deathÕs-head hawkmoths maintain control of their flight trajectories over long distances. The moths did not just fly with favorable tailwinds; during a given night, they also adjusted for head and crosswinds to precisely hold course. This behavior indicates that the moths use a sophisticated internal compass to maintain seasonally beneficial migratory trajectories independent of wind conditions, illuminating how insects traverse long distances to take advantage of seasonal resources. [ABSTRACT FROM AUTHOR]

Migratory animals are affected by various factors during their journeys, and the study of animal movement by radars has been instrumental in revealing key influences of the environment on flying migrants. Radars enable the simultaneous tracking of many individuals of almost all sizes within the radar range during day and night, and under low visibility conditions. We review how atmospheric conditions, geographic features and human development affect the behavior of migrating insects and birds as recorded by radars. We focus on flight initiation and termination, as well as in‐flight behavior that includes changes in animal flight direction, speed and altitude. We have identified several similarities and differences in the behavioral responses of aerial migrants including an overlooked similarity in the use of thermal updrafts by very small (e.g. aphids) and very large (e.g. vultures) migrants. We propose that many aerial migrants modulate their migratory flights in relation to the interaction between atmospheric conditions and geographic features. For example, aerial migrants that encounter crosswind may terminate their flight or continue their migration and may also drift or compensate for lateral displacement depending on their position (over land, near the coast or over sea). We propose several promising directions for future research, including the development and application of algorithms for tracking insects, bats and large aggregations of animals using weather radars. Additionally, an important contribution will be the spatial expansion of aeroecological radar studies to Africa, most of Asia and South America where no such studies have been undertaken. Quantifying the role of migrants in ecosystems and specifically estimating the number of departing birds from stopover sites using low‐elevation radar scans is important for quantifying migrant–habitat relationships. This information, together with estimates of population demographics and migrant abundance, can help resolve the long‐term dynamics of migrant populations facing large‐scale environmental changes. [ABSTRACT FROM AUTHOR]

Species with specialized ecological interactions present significant conservation challenges. In plants that attract pollinators with pollinator-specific chemical signals, geographical variation in pollinator species may indicate the presence of cryptic plant taxa. We investigated this phenomenon in the rare sexually deceptive orchid Drakaea elastica using a molecular phylogenetic analysis to resolve pollinator species boundaries, pollinator choice experiments and a population genetic study of the orchid. Pollinator choice experiments demonstrated the existence of two ecotypes within D. elastica, each attracting their own related but phylogenetically distinct pollinator species. Despite the presence of ecotypes, population genetic differentiation was low across populations at six microsatellite loci ( FST = 0.026). However, Bayesian STRUCTURE analysis revealed two genetic clusters, broadly congruent with the ecotype distributions. These ecotypes may represent adaptation to regional variation in pollinator availability and perhaps the early stages of speciation, with pronounced morphological and genetic differences yet to evolve. Resolution of the taxonomic status of the D. elastica ecotypes is required as this has implications for conservation efforts and allocation of management funding. Furthermore, any reintroduction programmes must incorporate knowledge of ecotype distribution and pollinator availability to ensure reproductive success in restored populations. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 124-140. [ABSTRACT FROM AUTHOR]

Pollinator behaviour directly affects patterns of pollen movement and outcrossing rates in plants. In orchids pollinated by sexual deception of insects, patterns of pollen movement are primarily determined by the mate-searching behaviour of the deceived males. Here, using a capture-mark-recapture study (CMR) and dietary analysis, we compare mate-searching behaviour in relation to local abundance of two pollinator species and explore the implications for pollen movement in sexually deceptive Drakaea (Orchidaceae). Drakaea are pollinated solely by the sexual deception of male thynnine wasps. The rare Drakaea elastica and widespread D. livida occur sympatrically and are pollinated by the rare but locally common Zaspilothynnus gilesi, and the widespread and abundant Z. nigripes, respectively. Local abundance was significantly different with Z. nigripes twice as abundant as Z. gilesi. For the 653 marked wasps, there was no significant difference in median movement distance between Z. gilesi and Z. nigripes. However, the maximum movement distance was twice as high for Z. gilesi (556 m) compared with Z. nigripes (267 m). This is up to three times greater than previously reported for thynnines in CMR studies. Recapture rates were six times higher in Z. gilesi (57%) compared to Z. nigripes (9%). Pollen loads and wasp longevity were similar, suggesting that this difference in recapture rate arises due to differences in the number of males moving at a scale >500 m rather than through diet or mortality. Differences in the frequency of longer movements may arise due to variation in the spatial distribution of the wingless females. We predict that pollen movement will largely be restricted to within populations of Drakaea (<500 m), with few movements between populations (>500 m). [ABSTRACT FROM AUTHOR]

In recent decades there has been a marked decline in most ortolan bunting Emberiza hortulana populations in temperate Europe, with many regional populations now extinct or on the brink of extinction. In contrast, Mediterranean and, as far as we know, eastern European popula-tions seem to have remained relatively stable. The causes of decline remain unclear but include: habitat loss and degradation, and related reduction in prey availability; climate change on the breeding grounds; altered population dynamics; illegal captures during migration; and environmental change in wintering areas. We review the current knowledge of the biology of the ortolan bunting and discuss the proposed causes of decline in relation to the different population trends in temperate and Mediterranean Europe. We suggest new avenues of research to identify the factors limiting ortolan bunting populations. The main evidence-based conservation measure that is likely to enhance habitat quality is the creation of patches of bare ground to produce sparsely vegetated foraging grounds in invertebrate-rich grassy habitats close to breeding areas. [ABSTRACT FROM PUBLISHER]

Artificial light at night (ALAN) is predicted to have far-reaching consequences for natural ecosystems given its influence on organismal physiology and behaviour, species interactions and community composition. Movement and predation are fundamental ecological processes that are of critical importance to ecosystem functioning. The natural movements and foraging behaviours of nocturnal invertebrates may be particularly sensitive to the presence of ALAN. However, we still lack evidence of how these processes respond to ALAN within a community context. We assembled insect communities to quantify their movement activity and predation rates during simulated Moon cycles across a gradient of diffuse night-time illuminance including the full range of observed skyglow intensities. Using radio frequency identification, we tracked the movements of insects within a fragmented grassland Ecotron experiment. We additionally quantified predation rates using prey dummies. Our results reveal that even low-intensity skyglow causes a temporal shift in movement activity from day to night, and a spatial shift towards open habitats at night. Changes in movement activity are associated with indirect shifts in predation rates. Spatio-temporal shifts in movement and predation have important implications for ecological networks and ecosystem functioning, highlighting the disruptive potential of ALAN for global biodiversity and the provision of ecosystem services. This article is part of the theme issue 'Light pollution in complex ecological systems'. [ABSTRACT FROM AUTHOR]

The authors discuss challenges facing the landscape-scale ecological restoration initiative planned at the 2012 United Nations Rio+20 Conference on Sustainable Development. They present several suggestions for effective allocation of resources to restoration projects, including determining the highest-demand disturbed and degraded ecosystems, prioritizing research to address knowledge gaps, and ensuring political support through communication of potential socioeconomic ecosystem services.

Abstract: Aim: Anthropogenic landscape change, such as urbanization, can affect community structure and ecological interactions. Furthermore, changes in ambient temperature and resource availability due to urbanization may affect migratory and non‐migratory species differently. However, the response of migratory species to urbanization is poorly investigated, and knowledge for invertebrates in particular is lacking. Our aim was to investigate whether there was a shift in community structure and phenology of hoverflies in urban landscapes, depending on migratory status. Location: Switzerland. Methods: Using a paired design, we compared urban and rural landscapes to investigate the impact of urbanization on the abundance, diversity and phenology of hoverflies. Furthermore, we tested whether migratory and non‐migratory species responded differently to urbanization. Results: We observed a difference in the response of migratory and non‐migratory hoverfly communities. Although the abundance of hoverflies was higher in the rural ecosystem, driven by a high abundance of migratory species, there was no difference in species richness between the land use types. However, the community structure of non‐migratory species was significantly different between urban and rural ecosystems. The phenology of hoverflies differed between the two ecosystems, with an earlier appearance in the year of migratory species in urban landscapes. Main conclusions: To our knowledge, this is the first study to investigate the response of migratory insect communities to urbanization. We demonstrated that migratory and non‐migratory hoverflies respond differently to urbanization. This highlights the importance of differentiating between trait and mobility groups to understand community assemblage patterns in anthropogenic landscapes. The differences in phenology supports the growing evidence that urbanization not only affects the phenology of vegetation, but also affects the higher trophic levels. Changes in the phenology and community composition of species as a result of anthropogenic landscape change may have important implications for the maintenance of key ecosystem functions, such as pollination. [ABSTRACT FROM AUTHOR]

Migration has evolved among many animal taxa and migratory species are found across all major lineages. Insects are the most abundant and diverse terrestrial migrants, with trillions of animals migrating annually. Partial migration, where populations consist of resident and migratory individuals, is ubiquitous among many taxa. However, the underlying mechanisms are relatively poorly understood and may be driven by physiological, behavioural or genetic variation within populations.We investigated the differences in migratory tendency between migratory and resident phenotypes of the hoverfly, Episyrphus balteatus, using tethered flight mills. Further, to test whether migratory flight behaviour is heritable and to disentangle the effects of environment during development, we compared the flight behaviour of laboratory-reared offspring of migrating, overwintering and summer animals. Offspring of migrants initiated more flights than those of resident individuals. Interestingly, there were no differences among wild-caught phenotypes with regard to number of flights or total flight duration. Low activity in field-collected migrants might be explained by an energy-conserving state that migrants enter into when under laboratory conditions, or a lack of suitable environmental cues for triggering migration. Our results strongly suggest that flight behaviour is heritable and that genetic factors influence migratory tendency in E. balteatus. These findings support the growing evidence that genetic factors play a role in partial migration and warrant careful further investigation. [ABSTRACT FROM AUTHOR]

Demand for restoration of resilient, self-sustaining, and biodiverse natural ecosystems as a conservation measure is increasing globally; however, restoration efforts frequently fail to meet standards appropriate for this objective. Achieving these standards requires management underpinned by input from diverse scientific disciplines including ecology, biotechnology, engineering, soil science, ecophysiology, and genetics. Despite increasing restoration research activity, a gap between the immediate needs of restoration practitioners and the outputs of restoration science often limits the effectiveness of restoration programs. Regrettably, studies often fail to identify the practical issues most critical for restoration success. We propose that part of this oversight may result from the absence of a considered statement of the necessary practical restoration science questions. Here we develop a comprehensive framework of the research required to bridge this gap and guide effective restoration. We structure questions in five themes: (1) setting targets and planning for success, (2) sourcing biological material, (3) optimizing establishment, (4) facilitating growth and survival, and (5) restoring resilience, sustainability, and landscape integration. This framework will assist restoration practitioners and scientists to identify knowledge gaps and develop strategic research focused on applied outcomes. The breadth of questions highlights the importance of cross-discipline collaboration among restoration scientists, and while the program is broad, successful restoration projects have typically invested in many or most of these themes. Achieving restoration ecology's goal of averting biodiversity losses is a vast challenge: investment in appropriate science is urgently needed for ecological restoration to fulfill its potential and meet demand as a conservation tool. [ABSTRACT FROM AUTHOR]

Pollination via sexual deception is hypothesised to be associated with more frequent outcrossing and greater pollen dispersal distances than strategies involving food-foraging behaviour. In this study, we investigated the behaviour and movement distances of Lissopimpla excelsa (Hymenoptera: Ichneumonidae), and their implications for the pollination of the sexually deceptive Cryptostylis ovata (Orchidaceae). Pollinator observations revealed that while L. excelsa will alight on multiple flowers within a single visit to a patch of orchids, the frequency of attempted copulation decreases with successive visits, suggesting that pollinator learning may inhibit within-patch pollen transfer. Mark-recapture demonstrated that 25% of wasps revisited inflorescences within a day and 50% revisited within a week. Despite the apparent site fidelity of some individuals, L. excelsa often move over large distances (maximum = 625 m), and are capable of dispersing pollen between patches. To resolve the consequences of pollination by sexual deception of ichneumonids, we compared our results with those from studies of other sexually deceptive systems. While pollination rates were comparable with other sexually deceptive orchids, L. excelsa showed high rates of column contact and moved over large distances relative to other sexually deceived pollinators. Among sexually deceptive orchids in general, the frequency of column contact was not correlated either with the frequency of pseudocopulation or with pollination rate. These results suggest that the consequences of pollination by sexual deception may vary extensively between plant taxa due to variation in floral traits, and behavioural differences between pollinator groups. [ABSTRACT FROM AUTHOR]

• Sexually deceptive orchids employ floral volatiles to sexually lure their specific pollinators. How and why this pollination system has evolved independently on multiple continents remains unknown, although preadaptation is considered to have been important. Understanding the chemistry of sexual deception is a crucial first step towards solving this mystery. • The combination of gas chromatography-electroantennographic detection (GC-EAD), GCMS, synthesis and field bioassays allowed us to identify the volatiles involved in the interaction between the orchid Drakaea glyptodon and its sexually attracted male thynnine wasp pollinator, Zaspilothynnus trilobatus. • Three alkylpyrazines and one novel hydroxymethyl pyrazine were identified as the sex pheromone of Z. trilobatus and are also used by D. glyptodon for pollinator attraction. Given that our findings revealed a new chemical system for plants, we surveyed widely across representative orchid taxa for the presence of these compounds. With one exception, our chemical survey failed to detect pyrazines in related genera. Collectively, no evidence for preadaptation was found. • The chemistry of sexual deception is more diverse than previously known. Our results suggest that evolutionary novelty may have played a key role in the evolution of sexual deception and highlight the value of investigating unusual pollination systems for advancing our understanding of the role of chemistry in evolution. [ABSTRACT FROM AUTHOR]

Small population size in plants is often associated with decreased fruit set through lower pollinator visitation and reduced offspring fitness as a result of inbreeding. Whether the potentially negative impacts of small population size are realized may be potentially influenced by the behaviour and ecology of pollinators., Here, we investigate changes in both guild composition and pollinator behaviour with plant population size in the bird-pollinated Anigozanthos flavidus ( Haemodoraceae) and the consequences for fruit set and seed germinability. We used a germination stimulant to reduce the potentially confounding affects of interpopulation variation in dormancy when quantifying seed germinability., All populations were visited in small numbers by western spinebills, while the behaviourally dominant New Holland honeyeaters only visited large populations. Fruit set was extremely high (mean = 96·4 ± 0·6%) regardless of population size., The percentage of foraging bouts interrupted by aggressive interactions tended to be less in small plant populations. The percentage of interrupted foraging bouts was as high as 31% in some populations, suggesting that aggression may frequently promote pollen movement. Western spinebills tended to visit fewer stems per plant than New Holland honeyeaters, a behaviour that potentially favours greater outcrossing., There was no relationship between seed germinability or seeds produced per capsule and plant population size, suggesting that the foraging behaviour of western spinebills provides sufficient pollinator services in small populations to mitigate the potential reduction in seed production and germinability., Our findings highlight that, even within a pollinator guild, differences in behaviour can have important implications for the fitness of plants in small populations, with the potential for some pollinators to provide unexpected levels of resilience. [ABSTRACT FROM AUTHOR]

The sun is the most reliable celestial cue for orientation available to daytime migrants. It is widely assumed that diurnal migratory insects use a 'time-compensated sun compass' to adjust for the changing position of the sun throughout the day, as demonstrated in some butterfly species. The mechanisms used by other groups of diurnal insect migrants remain to be elucidated. Migratory species of hoverflies (Diptera: Syrphidae) are one of the most abundant and beneficial groups of diurnal migrants, providing multiple ecosystem services and undergoing directed seasonal movements throughout much of the temperate zone. To identify the hoverfly navigational strategy, a flight simulator was used to measure orientation responses of the hoverflies Scaeva pyrastri and Scaeva selenitica to celestial cues during their autumn migration. Hoverflies oriented southwards when they could see the sun and shifted this orientation westward following a 6 h advance of their circadian clocks. Our results demonstrate the use of a time-compensated sun compass as the primary navigational mechanism, consistent with field observations that hoverfly migration occurs predominately under clear and sunny conditions. [ABSTRACT FROM AUTHOR]

The sun is the most reliable celestial cue for orientation available to daytime migrants. It is widely assumed that diurnal migratory insects use a 'time-compensated sun compass' to adjust for the changing position of the sun throughout the day, as demonstrated in some butterfly species. The mechanisms used by other groups of diurnal insect migrants remain to be elucidated. Migratory species of hoverflies (Diptera: Syrphidae) are one of the most abundant and beneficial groups of diurnal migrants, providing multiple ecosystem services and undergoing directed seasonal movements throughout much of the temperate zone. To identify the hoverfly navigational strategy, a flight simulator was used to measure orientation responses of the hoverflies Scaeva pyrastri and Scaeva selenitica to celestial cues during their autumn migration. Hoverflies oriented southwards when they could see the sun and shifted this orientation westward following a 6 h advance of their circadian clocks. Our results demonstrate the use of a time-compensated sun compass as the primary navigational mechanism, consistent with field observations that hoverfly migration occurs predominately under clear and sunny conditions. [ABSTRACT FROM AUTHOR]

Large migrating insects, flying at high altitude, often exhibit complex behaviour. They frequently elect to fly on winds with directions quite different from the prevailing direction, and they show a degree of common orientation, both of which facilitate transport in seasonally beneficial directions. Much less is known about the migration behaviour of smaller (10–70 mg) insects. To address this issue, we used radar to examine the high-altitude flight of hoverflies (Diptera: Syrphidae), a group of day-active, medium-sized insects commonly migrating over the UK. We found that autumn migrants, which must move south, did indeed show migration timings and orientation responses that would take them in this direction, despite the unfavourability of the prevailing winds. Evidently, these hoverfly migrants must have a compass (probably a time-compensated solar mechanism), and a means of sensing the wind direction (which may be determined with sufficient accuracy at ground level, before take-off). By contrast, hoverflies arriving in the UK in spring showed weaker orientation tendencies, and did not correct for wind drift away from their seasonally adaptive direction (northwards). However, the spring migrants necessarily come from the south (on warm southerly winds), so we surmise that complex orientation behaviour may not be so crucial for the spring movements. [ABSTRACT FROM AUTHOR]

Pollinator declines, changes in land use and climate-induced shifts in phenology have the potential to seriously affect ecosystem function and food security by disrupting pollination services provided by insects. Much of the current research focuses on bees, or groups other insects together as ‘non-bee pollinators’, obscuring the relative contribution of this diverse group of organisms. Prominent among the ‘non-bee pollinators’ are the hoverflies, known to visit at least 72% of global food crops, which we estimate to be worth around US$300 billion per year, together with over 70% of animal pollinated wildflowers. In addition, hoverflies provide ecosystem functions not seen in bees, such as crop protection from pests, recycling of organic matter and long-distance pollen transfer. Migratory species, in particular, can be hugely abundant and unlike many insect pollinators, do not yet appear to be in serious decline. In this review, we contrast the roles of hoverflies andbeesas pollinators, discusstheneed forresearchand monitoring of different pollinator responses to anthropogenic change and examine emerging research into large populations of migratory hoverflies, the threats they face and how they might be used to improve sustainable agriculture. [ABSTRACT FROM AUTHOR]

Many insect species are under threat from the anthropogenic drivers of global change. There have been numerous well‐documented examples of insect population declines and extinctions in the scientific literature, but recent weaker studies making extreme claims of a global crisis have drawn widespread media coverage and brought unprecedented public attention. This spotlight might be a double‐edged sword if the veracity of alarmist insect decline statements do not stand up to close scrutiny.We identify seven key challenges in drawing robust inference about insect population declines: establishment of the historical baseline, representativeness of site selection, robustness of time series trend estimation, mitigation of detection bias effects, and ability to account for potential artefacts of density dependence, phenological shifts and scale‐dependence in extrapolation from sample abundance to population‐level inference.Insect population fluctuations are complex. Greater care is needed when evaluating evidence for population trends and in identifying drivers of those trends. We present guidelines for best‐practise approaches that avoid methodological errors, mitigate potential biases and produce more robust analyses of time series trends.Despite many existing challenges and pitfalls, we present a forward‐looking prospectus for the future of insect population monitoring, highlighting opportunities for more creative exploitation of existing baseline data, technological advances in sampling and novel computational approaches. Entomologists cannot tackle these challenges alone, and it is only through collaboration with citizen scientists, other research scientists in many disciplines, and data analysts that the next generation of researchers will bridge the gap between little bugs and big data. [ABSTRACT FROM AUTHOR]

Radar is at the forefront for the study of broad‐scale aerial movements of birds, bats and insects and related issues in biological conservation. Radar techniques are especially useful for investigating species which fly at high altitudes, in darkness, or which are too small for applying electronic tags. Here, we present an overview of radar applications in biological conservation and highlight its future possibilities. Depending on the type of radar, information can be gathered on local‐ to continental‐scale movements of airborne organisms and their behaviour. Such data can quantify flyway usage, biomass and nutrient transport (bioflow), population sizes, dynamics and distributions, times and dimensions of movements, areas and times of mass emergence and swarming, habitat use and activity ranges. Radar also captures behavioural responses to anthropogenic disturbances, artificial light and man‐made structures. Weather surveillance and other long‐range radar networks allow spatially broad overviews of important stopover areas, songbird mass roosts and emergences from bat caves. Mobile radars, including repurposed marine radars and commercially dedicated 'bird radars', offer the ability to track and monitor the local movements of individuals or groups of flying animals. Harmonic radar techniques have been used for tracking short‐range movements of insects and other small animals of conservation interest. However, a major challenge in aeroecology is determining the taxonomic identity of the targets, which often requires ancillary data obtained from other methods. Radar data have become a global source of information on ecosystem structure, composition, services and function and will play an increasing role in the monitoring and conservation of flying animals and threatened habitats worldwide. [ABSTRACT FROM AUTHOR]

Nocturnal avian migration flyways remain an elusive concept, as we have largely lacked methods to map their full extent. We used the network of European weather radars to investigate nocturnal bird movements at the scale of the European flyway. We mapped the main migration directions and showed the intensity of movement across part of Europe by extracting biological information from 70 weather radar stations from northern Scandinavia to Portugal, during the autumn migration season of 2016. On average, over the 20 nights and all sites, 389 birds passed per 1 km transect per hour. The night with highest migration intensity showed an average of 1621 birds km–1 h–1 passing the radar stations, but there was considerable geographical and temporal variation in migration intensity. The highest intensity of migration was seen in central France. The overall migration directions showed strong southwest components. Migration dynamics were strongly related to synoptic wind conditions. A wind‐related mass migration event occurred immediately after a change in wind conditions, but quickly diminished even when supporting winds continued to prevail. This first continental‐scale study using the European network of weather radars demonstrates the wealth of information available and its potential for investigating large‐scale bird movements, with consequences for ecosystem function, nutrient transfer, human and livestock health, and civil and military aviation. [ABSTRACT FROM AUTHOR]

Abstract: Most research on pollination has focussed on a subset of insect taxa within a narrow time window during daylight hours. As a consequence, we have a limited understanding of the diversity and activity of flower visitors during the night or belonging to taxa other than bees or syrphid flies. Here, we quantified the abundance and species richness of flower visitors in ruderal meadows over repeated 24‐h cycles (i.e. day and night), and identified abiotic factors influencing these patterns. From the plant perspective, we investigated the likelihood of being visited by an insect across a 24‐h cycle. Activity of flower‐visiting insects never dropped to zero over 24‐h. During the day, non‐syrphid Diptera and Hymenoptera were the most abundant, and species‐rich groups of flower visitors, Lepidoptera and Coleoptera during night. While two of the seven most frequently visited plant species were most likely to be visited during the day, five also had a high likelihood to be visited during the night. The abundance and species richness of flower visitors was positively related to temperature during both the day and the night, whereas there was only a positive relationship with brightness during the day. We conclude that non‐syrphid Diptera and nocturnal flower visitors are currently underappreciated. As the latter seem to respond differently to abiotic factors compared to diurnal species, they may potentially increase response diversity and resilience of plant‐pollinator communities. There is an urgent need to improve our understanding of their ecological role and potential decline due to global change. [ABSTRACT FROM AUTHOR]

An increasing diversity of highly specialized pollination systems are being discovered, many of which are likely to be vulnerable to anthropogenic landscape modification. Here, we investigate if a specialized pollination system limits the persistence of C aladenia huegelii ( Orchidaceae), an endangered species pollinated by sexual deception of thynnine wasps. Once locally common in part of its geographical range, C. huegelii is now largely restricted to small habitat remnants in urban areas. Pollinator surveys coupled with DNA barcoding detected a single pollinator taxon, a small form of Macrothynnus insignis. Phylogenetic analysis revealed that small M. insignis from within the range of C. huegelii are strongly divergent from other wasp populations, suggesting that some reproductive isolation may exist. Although common in intact landscapes outside the range of C. huegelli, small M. insignis individuals were recorded at only 4% of sites in suitable C. huegelii habitat. Accordingly, reproductive success in C. huegelii was low compared with related Caladenia spp., with 33-60% of populations failing to set fruit in any given year. As such, populations are likely to now persist primarily through individual plant longevity rather than reproduction. Due to the low reproductive success of C. huegelii, ongoing human intervention will almost certainly be needed to sustain the species. Future research will need to focus on optimizing hand pollination to maintain reproduction and high seed fitness. © 2015 The Linnean Society of London, B otanical J ournal of the L innean S ociety, 2015, 179, 511-525. [ABSTRACT FROM AUTHOR]