Helen E. Roy

Harmonia axyridis in Europe: spread and distribution of a non-native coccinellid

Native to Asia, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is considered an invasive alien ladybird in Europe and North America, where it was widely introduced as a biological control agent of aphids and coccids. In Europe, H. axyridis was sold by various biological control companies from 1995 in France, Belgium and the Netherlands, and was also intentionally released in at least nine other countries. It has spread very rapidly, particularly since 2002, and is now regarded as established in thirteen European countries. The established range extends from Denmark in the north to southern France in the south, and from Czech Republic in the east to Great Britain in the west. In this paper we map the spread and distribution of H. axyridis in Europe, and examine the situation on a country-by-country basis. We report first records of the species in five countries; Spain, Sweden, Denmark, Czech Republic and Italy; and first evidence of H. axyridis establishment in the latter three countries. Despite releases of H. axyridis in Portugal, Spain and Greece, there is little evidence of establishment in southern Europe. It is predicted that the spread and increase within Europe will continue and that H. axyridis will become one of the most widely distributed coccinellids in the continent.

Ecological genetics of invasive alien species

There is growing realisation that integrating genetics and ecology is critical in the context of biological invasions, since the two are explicitly linked. So far, the focus of ecological genetics of invasive alien species (IAS) has been on determining the sources and routes of invasions, and the genetic make-up of founding populations, which is critical for defining and testing ecological and evolutionary hypotheses. However an ecological genetics approach can be extended to investigate questions about invasion success and impacts on native, recipient species. Here, we discuss recent progress in the field, provide overviews of recent methodological advances, and highlight areas that we believe are of particular interest for future research. First, we discuss the main insights from studies that have inferred source populations and invasion routes using molecular genetic data, with particular focus on the role of genetic diversity, adaptation and admixture in invasion success. Second, we consider how genetic tools can lead to a better understanding of patterns of dispersal, which is critical to predicting the spread of invasive species, and how studying invasions can shed light on the evolution of dispersal. Finally, we explore the potential for combining molecular genetic data and ecological network modelling to investigate community interactions such as those between predator and prey, and host and parasite. We conclude that invasions are excellent model systems for understanding the role of natural selection in shaping phenotypes and that an ecological genetics approach offers great potential for addressing fundamental questions in invasion biology.

Interactions Between Entomopathogenic Fungi and Other Natural Enemies: Implications for Biological Control

Pathogens and arthropod natural enemies may contribute to the suppression of insect pest populations either as individual species or as species complexes. However, because natural enemies of insects have evolved and function in a multitrophic context it is important to assess interactions within complexes of natural enemies if they are to be exploited effectively in pest management. Natural enemies can interact either synergistically/additively (e.g. enhanced transmission and dispersal of insect pathogens) or antagonistically (e.g. parasitism/infection, predation and competition). In this paper, studies assessing the potential interactions between insect and fungal natural enemies are reviewed. In general, these studies indicate the positive nature of the interactions between arthropod natural enemies and fungal pathogens with respect to the control of insect populations. More work is required to investigate further the many ways in which the natural enemy community interacts in the agroecosystem

No saturation in the accumulation of alien species worldwide

Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.

From biological control to invasion : the ladybird harmonia axyridis as a model species

Foreword: H.E. Roy, E.W. Wajnberg. 1. Harmonia axyridis in Europe: spread and distribution of a non-native coccinellid: P.M.J. Brown et al. 2. Bad side of a good beetle: the North American experience with Harmonia axyridis: R.L. Koch, T.L. Galvan. 3. Harmonia axyridis: an environmental risk assessment for Northwest Europe: J.C. van Lenteren et al. 4. Harmonia axyridis in Great Britain: analysis of the spread and distribution of a non-native coccinellid: P.M.J. Brown et al. 5. Invasion history, habitat preferences and phenology of the invasive ladybird Harmonia axyridis in Belgium: T. Adriaens et al. 6. Phenotypic variation in invasive and biocontrol populations of the harlequin ladybird Harmonia axyridis: E. Lombaert et al. 7. Predicting the potential distribution of the multicoloured Asian ladybeetle, Harmonia axyridis, using the CLIMEX model: J. Poutsma et al. 8. Harmonia axyridis: What will stop the invader?: A.O. Soares et al. 9. Intraguild predation involving Harmonia axyridis: a review of current knowledge and future perspectives: J.K. Pell et al. 10. Intraguild predation of immature stages of British and Japanese coccinellids by the invasive ladybird Harmonia axyridis: R.L. Ware, M.E.N. Majerus. 11. Chemical protection of Calvia quatuordecimguttata eggs against intraguild predation by the invasive ladybird Harmonia axyridis: R.L. Ware et al. 12. Pollen as an alternative food for Harmonia axyridis: N. Berkvens et al. 13. Influence of diet and photoperiod on development and reproduction of European populations of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae): N. Berkvens et al. 14. Ladybirds population dynamics in potato: comparison of native species and an invasive species, Harmonia axyridis: J.-P. Jansen, L. Hautier. 15. Current and potential management strategies against Harmonia axyridis: M. Kenis et al. 16. Interactions between the parasitoid wasp Dinocampus coccinellae and two species of coccinellid from Japan and Britain: S. Koyama, M.E.N. Majerus. 17. Interactions between the fungal pathogen Beauvaria bassiana and three species of ladybird: Harmonia axyridis, Coccinella septempunctata and Adalia bipunctata: H.E. Roy et al. 18. Estimation of mortality by entomophages on exotic Harmonia axyridis vs native Adalia bipunctata in northern Italy: G. Burgio et al.

Lessons from lady beetles: accuracy of monitoring data from US and UK citizen‐science programs

Citizen scientists have the potential to play a crucial role in the study of rapidly changing lady beetle (Coccinellidae) populations. We used data derived from three coccinellid-focused citizen-science programs to examine the costs and benefits of data collection from direct citizen-science (data used without verification) and verified citizen-science (observations verified by trained experts) programs. Data collated through direct citizen science overestimated species richness and diversity values in comparison to verified data, thereby influencing interpretation. The use of citizen scientists to collect data also influenced research costs; our analysis shows that verified citizen science was more cost effective than traditional science (in terms of data gathered per dollar). The ability to collect a greater number of samples through direct citizen science may compensate for reduced accuracy, depending on the type of data collected and the type(s) and extent of errors committed by volunteers.

Decline in native ladybirds in response to the arrival of Harmonia axyridis: early evidence from England

1. Harmonia axyridis (Coleoptera: Coccinellidae) is an invasive non‐native ladybird in Europe, where it was introduced as a biological control agent of aphids and coccids.

The harlequin ladybird, Harmonia axyridis: global perspectives on invasion history and ecology

The harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is native to Asia but has been intentionally introduced to many countries as a biological control agent of pest insects. In numerous countries, however, it has been introduced unintentionally. The dramatic spread of H. axyridis within many countries has been met with considerable trepidation. It is a generalist top predator, able to thrive in many habitats and across wide climatic conditions. It poses a threat to biodiversity, particularly aphidophagous insects, through competition and predation, and in many countries adverse effects have been reported on other species, particularly coccinellids. However, the patterns are not consistent around the world and seem to be affected by many factors including landscape and climate. Research on H. axyridis has provided detailed insights into invasion biology from broad patterns and processes to approaches in surveillance and monitoring. An impressive number of studies on this alien species have provided mechanistic evidence alongside models explaining large-scale patterns and processes. The involvement of citizens in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable. Harmonia axyridis has successfully been used as a model invasive alien species and has been the inspiration for global collaborations at various scales. There is considerable scope to expand the research and associated collaborations, particularly to increase the breadth of parallel studies conducted in the native and invaded regions. Indeed a qualitative comparison of biological traits across the native and invaded range suggests that there are differences which ultimately could influence the population dynamics of this invader. Here we provide an overview of the invasion history and ecology of H. axyridis globally with consideration of future research perspectives. We reflect broadly on the contributions of such research to our understanding of invasion biology while also informing policy and people.

Entomopathogenic fungi and insect behaviour: from unsuspecting hosts to targeted vectors

The behavioural response of an insect to a fungal pathogen will have a direct effect on the efficacy of the fungus as a biological control agent. In this paper we describe two processes that have a significant effect on the interactions between insects and entomopathogenic fungi: (a) the ability of target insects to detect and avoid fungal pathogens and (b) the transmission of fungal pathogens between host insects. The behavioural interactions between insects and entomopathogenic fungi are described for a variety of fungal pathogens ranging from commercially available bio-pesticides to non-formulated naturally occurring pathogens. The artificial manipulation of insect behaviour using dissemination devices to contaminate insects with entomopathogenic fungi is then described. The implications of insect behaviour on the use of fungal pathogens as biological control agents are discussed.

Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain

Invasive alien species (IAS) are considered one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change. Horizon scanning, the systematic examination of future potential threats and opportunities, leading to prioritization of IAS threats is seen as an essential component of IAS management. Our aim was to consider IAS that were likely to impact on native biodiversity but were not yet established in the wild in Great Britain. To achieve this, we developed an approach which coupled consensus methods (which have previously been used for collaboratively identifying priorities in other contexts) with rapid risk assessment. The process involved two distinct phases: Preliminary consultation with experts within five groups (plants, terrestrial invertebrates, freshwater invertebrates, vertebrates and marine species) to derive ranked lists of potential IAS. Consensus-building across expert groups to compile and rank the entire list of potential IAS. Five hundred and ninety-one species not native to Great Britain were considered. Ninety-three of these species were agreed to constitute at least a medium risk (based on score and consensus) with respect to them arriving, establishing and posing a threat to native biodiversity. The quagga mussel, Dreissena rostriformis bugensis, received maximum scores for risk of arrival, establishment and impact; following discussions the unanimous consensus was to rank it in the top position. A further 29 species were considered to constitute a high risk and were grouped according to their ranked risk. The remaining 63 species were considered as medium risk, and included in an unranked long list. The information collated through this novel extension of the consensus method for horizon scanning provides evidence for underpinning and prioritizing management both for the species and, perhaps more importantly, their pathways of arrival. Although our study focused on Great Britain, we suggest that the methods adopted are applicable globally.