The invasion history, distribution and colour pattern forms of the harlequin ladybird beetle Harmonia axyridis (Pall.) (Coleoptera, Coccinellidae) in Slovakia, Central Europe

The harlequin ladybird beetle Harmonia axyridis (Coleoptera, Coccinellidae) has invaded and established in Slovakia. Following unintentional introduction in 2008, the spread of the alien coccinellid was very fast. By the end of 2009, it was recorded across the whole country, and by the end of 2012 it was widely distributed and common in various habitats, particularly gardens, orchards and urban areas, where it was most frequent on trees. The rate of eastward spread was approximately 200 km year-1, similar to the overall rate of spread in Europe. Between 2008 and 2012, the coccinellid was recorded in a total of 153 localities, in altitudes ranging from 98 to 1, 250 m. Most records of this species were made in lowlands, hilly areas and valleys separating mountain ridges. However, it was only rarely documented in areas above 700 m a.s.l. The non-melanic colour form (f. succinea) was dominant along a longitudinal transect including eight urban areas across Slovakia, with the frequency of melanic forms (f. spectabilis and f. conspicua together) between 6.3 and 19.2% and a median equal to 10.5%. The invasion history and distribution of H. axyridis in Slovakia are discussed with regard to the time sequence of records, rate of spread, altitudinal distribution, anthropogenic dispersal, effective recording, proportion of melanic forms and other relevant aspects associated with the spread of this successful invader

Factors determining variation in colour morph frequencies in invasive Harmonia axyridis populations

The Harlequin ladybird Harmonia axyridis Pallas, native to eastern Asia, is an invasive, non-native species that has recently achieved an almost worldwide distribution. A conspicuous feature of this species is colour polymorphism of the elytra. In its native area, the populations consist of a recessive non-melanic morph, several dominant melanic morphs and small numbers of other (rare) morphs. The morph proportions in native populations have been intensively studied and vary with geographic area, climate and time. In contrast, colour polymorphism in invaded regions has been little studied. We examine and try to account for the morph frequencies observed across the different invaded regions. In America, monomorphic populations consist of the non-melanic morphs while European populations contain also melanic morphs. In particular geographic areas of Europe, the average percentage of the non-melanic morphs varied between 78 and 99%. It was highest in the lowlands of northern Italy and central and northern Europe and decreased in the Alps and western (Spain, UK) and eastern (southeast Russia) margins of the recently invaded area. In central Europe the frequency of the non-melanic morphs decreased over the course of the year but increased over the years from 2010 to 2018. The local differences might thus arise through gradual change of the morph composition of the founder invasive, non-native population. However, the variation in non-melanic morph frequency was not correlated with climatic characteristics that might affect coccinellid polymorphism. The observed rate of change in morph proportions in our data was too small to explain the diversification of what was supposedly a uniform invasive, non-native population at the point of introduction

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

The status, ecology and conservation of Lycaena dispar (Lycaenidae: Lycaenini) in Europe

Volume: 21Start Page: 94End Page: 10