Entomopathogenic fungi and invasional meltdown

Invasive non-native (alien) species are considered to be one of the greatest threats to biodiversity (Millenium Ecosystem Assessment 2005) through predation, competition, hybridisation or as vectors of disease (Hulme et al., 2009). The movement of peole and goods is increasing the rate of invasive alien species arriving in countries around the globe. A recent inventory of alien species in Europe revealed a figure of 11000 species (Hulme et al., 2009) but it is recognised that this is a first approximation and likely to be an underestimate (Olenin & Didžiulis, 2009). The distinction between native species and alien species is problematic; species have been moving around the world over millennia and the origin of many species is uncertain. It is also evident that many archaeophytes and archaeozoans establish within native communities without detrimental effects on species and ecosystem processes (Pyšek et al., 2005). However, the small proportion of alien species that are problematic (invasive) are both ecologically and economically costly (Hulme et al., 2009). Furthermore, historically species movements have occurred within continents but in recent decades an increasing proportion of alien species are from other continents (Hulme et al., 2009). Alien species originating from within a continent are predicted to be less invasive than those from other continents (Hulme et al., 2009)

Pathogen avoidance by insect predators

Insects can detect cues related to the risk of attack by their natural enemies. Pathogens are among the natural enemies of insects and entomopathogenic fungi attack a wide array of host species. Evidence documents that social insects in particular have adapted behavioural mechanisms to avoid infection by fungal pathogens. These mechanisms are referred to as 'behavioural resistance'. However, there is little evidence for similar adaptations in non-social insects. We have conducted experiments to assess the potential of common insect predators to detect and avoid their entomopathogenic fungal natural enemy Beauveria bassiana. The predatory bug Anthocoris nemorum was able to detect and avoid nettle leaves that were treated with B. bassiana. Females laid fewer eggs on leaf halves contaminated with the pathogen. Similarly, females were very reluctant to contact nettle leaves contaminated with the fungus compared to uncontaminated control leaves in ‘no-choice’ experiments. Adult seven spot ladybirds, Coccinella septempunctata, overwinter in the litter layer often in groups. Adult C. septempunctata modified their overwintering behaviour in relation to the presence of B. bassiana conidia in soil and sporulating conspecifics by moving away from sources of infection. Furthermore active (non-overwintering) adult C. septempunctata were also able to detect and avoid B. bassiana conidia on different substrates; bean leaves, soil and sporulating on dead conspecifics. Our studies show that insect predators have evolved mechanisms to detect and avoid pathogens that they are susceptible to. Fungal pathogens may be significant mortality factors among populations of insect predators, especially long-lived species that must diapause before reproduction. Likewise, actively foraging species are more likely to come in contact with pathogens than predators that sit and wait for prey. These particular groups of insects will benefit from adaptations to avoid pathogens

Alien species related information systems and information management

The conservation of biodiversity and ecosystem services is severely challenged by biological invasions. The rapid globalisation and increasing trends of trade, travel, and transport in recent decades have caused increasing rates of new introductions through various pathways in both aquatic and terrestrial biomes. The Convention on Biological Diversity (CBD) calls the Contracting Parties “to prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species”. To achieve this target there is a need for accurate, detailed, and timely information on alien species, such as species distribution, pathways of introduction, impacts, and effective management measures. The CBD calls for the “compilation and dissemination of information on alien species that threaten ecosystems, habitats, or species, to be used in the context of any prevention, introduction and mitigation activities”. Such information is necessary to implement policies for the efficient prevention, early detection, rapid response, and management of biological invasions and also to evaluate management measures. However, often data are limited for certain species or ecosystems, making evaluations of impact or an understanding of management options difficult. In recognition of this, a large number of information systems and online databases have been created that document biological invasions on a national, supranational, or global scale, but also act to raise awareness and improve surveillance of biological invasions

Fifty years of the Biological Records Centre

In this special issue of the Biological Journal of the Linnean Society, we celebrate 50 years of the Biological Records Centre (BRC) but, more importantly, we celebrate the pioneers of BRC and the volunteer recording community. It is inspiring to consider the many individuals who have contributed to the rich legacy of biological recording since the 16th Century. The core activity of BRC has remained unchanged since its foundation in 1964: working in partnership with volunteer recording schemes and societies to collate, manage, disseminate, and interpret species observations (biological records). However, innovative technologies and the development of statistical approaches are taking biological recording in new and exciting directions. The large spatial coverage and increasingly fine-scale spatial precision of biological records enable ecologists to examine large-scale processes that would be impossible to address without the contribution of voluntary recorders

Encounters with an alien: Harmonia axyridis in Europe

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an aphidophagous coccinellid, native to central and eastern Asia (Kuznetsov, 1997; Majerus et al., 2006). It was introduced to Europe in 1982 and has spread rapidly since, for example, 100 km per year in Britain. Harmonia axyridis has been recorded as established in: France (first report), Germany, Belgium, Netherlands, Switzerland, Luxembourg, England, Czech Republic, Italy, Austria, Denmark, Norway, Poland, Wales, Liechtenstein, Scotland, Hungary, Slovakia and Bulgaria (last report). The IOBC/WPRS (International Organization for Biological Control/Western Palaearctic Regional Section) Study Group “Benefits and Risks of Exotic Biological Control Agents” was established to encourage collaborative research on this species and other exotic biological control agents. In this paper we describe some of the current activity in Europe

Citizen science reveals the distribution of the invasive harlequin ladybird (Harmonia axyridis Pallas) in Argentina

The harlequin ladybird (Harmonia axyridis) was introduced in numerous countries around the world as a biological control agent but nowadays it is considered as a pest itself. It is a highly invasive species that has negative impacts on native biodiversity, may affect some crops, and causes a nuisance to humans. Despite its relevance worldwide, the invasion by H. axyridis in South America has received little attention. Here we used a citizen science approach to study the distribution of H. axyridis in Argentina where the species was intentionally introduced in 1986. We also informally tested and evaluated the preferences for different methods for reporting records: iNaturalist website, Google form, email, WhatsApp, and Facebook. Most records were reported through WhatsApp and iNaturalist. We found that H. axyridis is widely distributed in Argentina but there are large gaps, particularly in arid regions. The invasion seems to be recent in the south of the country. Citizen science is a valuable tool for mapping invasive alien species in a large country like Argentina, and will help to monitor the continuous expansion of H. axyridis

Focal plant observations as a standardised method for pollinator monitoring: opportunities and limitations for mass participation citizen science

Background: Recently there has been increasing focus on monitoring pollinating insects, due to concerns about their declines, and interest in the role of volunteers in monitoring pollinators, particularly bumblebees, via citizen science. Methodology/Principal Findings: The Big Bumblebee Discovery was a one-year citizen science project run by a partnership of EDF Energy, the British Science Association and the Centre for Ecology & Hydrology which sought to assess the influence of the landscape at multiple scales on the diversity and abundance of bumblebees. Timed counts of bumblebees ( Bombus spp.; identified to six colour groups) visiting focal plants of lavender (Lavendula spp.) were carried out by about 13 000 primary school children (7 – 11 years old) from over 400 schools across the UK. 3948 reports were received totalling 26 868 bumblebees. We found that while the wider landscape type had no significant effect on reported bumblebee abundance, the local proximity to flowers had a significant effect (fewer bumblebees where other flowers were reported to be > 5m away from the focal plant). However, the rate of mis-identifcation, revealed by photographs uploaded by participants and a photo-based quiz, was high. Conclusions/Significance: Our citizen science results support recent research on the importance of local floral resources on pollinator abundance. Timed counts of insects visiting a lure plant is potentially an effective approach for standardised pollinator monitoring, engaging a large number of participants with a simple protocol. However, the relatively high rate of mis-identifications (compared to reports from previous pollinator citizen science projects) highlights the importance of investing in resources to train volunteers. Also, to be a scientifically valid method for enquiry, citizen science data needs to be sufficiently high quality, so receiving supporting evidence (such as photographs) would allow this to be tested and for records to be verified

Thinking like a naturalist: enhancing computer vision of citizen science images by harnessing contextual data

1. The accurate identification of species in images submitted by citizen scientists is currently a bottleneck for many data uses. Machine learning tools offer the potential to provide rapid, objective and scalable species identification for the benefit of many aspects of ecological science. Currently, most approaches only make use of image pixel data for classification. However, an experienced naturalist would also use a wide variety of contextual information such as the location and date of recording. 2. Here, we examine the automated identification of ladybird (Coccinellidae) records from the British Isles submitted to the UK Ladybird Survey, a volunteer‐led mass participation recording scheme. Each image is associated with metadata; a date, location and recorder ID, which can be cross‐referenced with other data sources to determine local weather at the time of recording, habitat types and the experience of the observer. We built multi‐input neural network models that synthesize metadata and images to identify records to species level. 3. We show that machine learning models can effectively harness contextual information to improve the interpretation of images. Against an image‐only baseline of 48.2%, we observe a 9.1 percentage‐point improvement in top‐1 accuracy with a multi‐input model compared to only a 3.6% increase when using an ensemble of image and metadata models. This suggests that contextual data are being used to interpret an image, beyond just providing a prior expectation. We show that our neural network models appear to be utilizing similar pieces of evidence as human naturalists to make identifications. 4. Metadata is a key tool for human naturalists. We show it can also be harnessed by computer vision systems. Contextualization offers considerable extra information, particularly for challenging species, even within small and relatively homogeneous areas such as the British Isles. Although complex relationships between disparate sources of information can be profitably interpreted by simple neural network architectures, there is likely considerable room for further progress. Contextualizing images has the potential to lead to a step change in the accuracy of automated identification tools, with considerable benefits for large‐scale verification of submitted records

Improving species distribution models for invasive non‐native species with biologically informed pseudo‐absence selection

Aim: We present a novel strategy for species distribution models (SDMs) aimed at predicting the potential distributions of range‐expanding invasive non‐native species (INNS). The strategy combines two established perspectives on defining the background region for sampling “pseudo‐absences” that have hitherto only been applied separately. These are the accessible area, which accounts for dispersal constraints, and the area outside the environmental range of the species and therefore assumed to be unsuitable for the species. We tested an approach to combine these by fitting SDMs using background samples (pseudo‐absences) from both types of background. Location: Global. Taxon: Invasive non‐native plants: Humulus scandens, Lygodium japonicum, Lespedeza cuneata, Triadica sebifera, Cinnamomum camphora. Methods: Presence‐background (or presence‐only) SDMs were developed for the potential global distributions of five plant species native to Asia, invasive elsewhere and prioritised for risk assessment as emerging INNS in Europe. We compared models where the pseudo‐absences were selected from the accessible background, the unsuitable background (defined using biological knowledge of the species’ key limiting factors) or from both types of background. Results: Combining the unsuitable and accessible backgrounds expanded the range of environments available for model fitting and caused biological knowledge about ecological unsuitability to influence the fitted species‐environment relationships. This improved the realism and accuracy of distribution projections globally and, generally, within the species’ ranges. Main conclusions: Correlative SDMs remain valuable for INNS risk mapping and management, but are often criticised for a lack of biological underpinning. Our approach partly addresses this concern by using prior knowledge of species’ requirements or tolerances to define the unsuitable background for modelling, while also accommodating dispersal constraints through considerations of accessibility. It can be implemented with current SDM software and results in more accurate and realistic distribution projections. As such, wider adoption has potential to improve SDMs that support INNS risk assessment