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   Harmonia axyridis (insect)
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    Overwintering aggregation of the Multicoloured Asian Ladybird, near Antwerpen (Photo: Wouter Vanreusel)

    Overwintering aggregation of the Multicoloured Asian Ladybird, near Antwerpen (Photo: Rollin Verlinde)

    Larvae of the Multicoloured Asian Ladybird often behave as intraguild predators towards the larvae of indigenous aphid predators [here feeding on a larva of the two-spot Ladybird, Adalia bipunctata] (Photo: Louis Hautier)

    Adult of the Multicoloured Asian Ladybird (Photo: Jeroen Mentens)

    Taxonomic name: Harmonia axyridis (Pallas)
    Common names: Asian lady beetle, Asiatischer Marienkafer, halloween lady beetle, harlequin lady beetle, Japanese lady beetle, la coccinelle asiatique, multicolored Asian lady beetle, multivariate lady beetle, pumpkin lady beetle, southern lady beetle, veelkeurig aziatisch lieveheersbeestje
    Organism type: insect
    Harmonia axyridis (lady beetle) is native to Asia and has been used extensively around the world for biological control of various aphid species. While it is a popular control agent, it has also brought with it several negative effects. Its establishment appears to decrease the diversity of native Coccinellidae. Harmonia axyridis can also quickly become a human nuisance when it seeks shelter during the winter months and takes up residency in the walls and insulation of houses and other structures. Surprisingly, Harmonia axyridis has also attained status as a pest of fruit production; particularly in the vineyards of the Midwestern USA.
    Adults of H. axyridis, which are larger than most of other ladybird species, measure 5-8mm. They are oval in shape and are convex. The elytra usually display a wide transverse "keel" at the apex. They are a highly coloured polymorphic with elytra ranging from pale yellow-orange to black bearing 0-19 spots. The head, antennae and mouthparts are generally straw yellow but are sometimes tinged with black. The pronotum is similarly straw yellow with up to five black spots, or with lateral spots usually joined to form two curved lines, an M-shaped mark, or a solid trapezoid. The larvae which have tubercles and spines are elongate and somewhat flattened, mature larvae are distinctive in their colouring. The overall colour is mostly black to dark bluish-gray, with a prominent bright yellow-orange patch extending over the dorso-lateral lobes of abdominal segments 1-5 on each side (Adriaens et al. 2003; Koch, 2003).
    Similar Species
    Hippodamia convergens

    Occurs in:
    agricultural areas, natural forests, planted forests, riparian zones, ruderal/disturbed, scrub/shrublands, urban areas, wetlands
    Habitat description
    Harmonia axyridis are known to colonise a wide range of habitats. They are found in cropping areas, meadows and semi-natural areas (Branquart, 2004). In North America they are found on a variety of nursery, ornamental, and field crops, including cotoneaster, rose, Christmas trees, apple, pecan, alfalfa, wheat, cotton, tobacco, and small grains (Cornell University, 2004). In Belgium they have ben recorded on deciduous trees, especially lime (Tilia sp.) and maple (Acer sp.). They tend to overwinter in buildings where they aggregate in secluded dark places (Branquart, 2004).
    General impacts
    Intraguild predation by H. axyridis is seen as a potential mechanism leading to displacement of native coccinellid species. H. axyridis appears to be a top predator in the guild of aphidophagous insects. Many studies indicate that H. axyridis uses other members of the aphidophagous guild as a food source (Koch, 2003). The intensity of predation by H. axyridis on other guild members appears to be inversely related to aphid density (Burgio et al. 2002).
    In a study conducted by Koch et al. (2003) the authors found that H. axyridis can act as a potential stressor to populations of monarch butterflies (Danaus plexippus).

    Cornell University (2004) states that, "H. axyridis has become a major nuisance to homeowners because of its habit of invading houses and buildings in large numbers while searching for protected sites to over winter in the fall and appearing again on warm, sunny days in February and March. In addition, beetles may get in picnic food and drinks; "swarm" like bees and land on people." Jones and Boggs (Undated) report that, H. axyridis demonstrate a defense mechanism called reflex bleeding. When disturbed, they exude a yellow-orange body fluid. This has a foul odor and can permanently stain walls, drapes, carpeting, etc. Some people are sensitive or allergic to the fluid that secrete, it can cause a stinging sensation and contact dermatitis.

    There is concern that H. axyridis may be a pest of fruit production. Koch et al. (2004) and Koch and Hutchinson (2003a) report that during autumn, the beetles show a tendency to aggregate on late season fruits, such as grapes, apples, and raspberries. In some cases, H. axyridis has been reported feeding on fruits that have been damaged by birds or other insects. They further state that the extent of this damage is uncertain but that there is greater concern over the beetle becoming a contaminant in vineyards. The difficulty in removing beetles from clusters of grapes may result in the beetles being crushed with grapes during processing and contamination of wine being produced.

    Harmonia axyridis is widely used as a biocontrol agent for reducing pest aphid populations in greenhouses, orchards and gardens in North America since 1916 and in Western Europe since 1982 (Adriaens et al. 2003; Koch, 2003). In several cases, this coccinellid has proven to be an effective biocontrol agent, particularly in pecans groves in southern USA.
    Adriaens et al. (2003) offer the following reasons as to why H. axyridis is such a successful and good colonizer. Firstly, it has a wide trophic niche (the niche the organism occupies in the food chain) and a high level of phenotypic plasticity (their behaviour or morphology varies with changing environmental conditions) for several life-history traits; secondly its voraciousness and intra-guild interactions with other aphidophagous species and finally its strong dispersal capacities and ability to undertakes long range migrations to over-wintering sites.
    Geographical range
    Native range: Asia (Tourniaire et al. 2000). The presumed native distribution of H. axyridis extends from the Altai Mountains in the west to the Pacific Coast in the east, and from southern Siberia in the north to southern China in the south (Koch, 2003)
    Known introduced range: Europe, North America, and South America (Koch, 2003; Adriaens et al.. 2003; Jones and Boggs, UNDATED; De Almeida and da Silva, 2002).
    Introduction pathways to new locations
    Biological control: H. axyridis has been widely used for reducing pest aphid populations in greenhouses, orchards and gardens in North America since 1916 and in Western Europe since 1982 (Koch, 2003; Adriaens et al. 2003).
    Other: The argument has been made that the current populations of H. axyridis in North America may have stemmed from accidental sea-port introductions (Koch, 2003).

    Local dispersal methods
    Natural dispersal (local): Cornell University (2004) states that, “H. axyridis has become a major nuisance to homeowners because of its habit of invading houses and buildings in large numbers while searching for protected sites to over winter in the fall and appearing again on warm, sunny days in February and March".
    Management information
    Physical: Management of H. axyridis in the household setting begins by preventing the beetles from entering the building. Any cracks or holes leading from the exterior to the interior of the home should be sealed with caulking or covered with a fine mesh screen (Koch and Hutchison 2003a).

    Chemical: In cases of persistent and severe infestations, exterior applications of insecticides (e.g., synthetic pyrethroids) can be applied to prevent H. axyridis from entering a building (Koch, 2003; Koch and Hutchison 2003b). The insecticides should be applied prior to the infestation, and focused around windows and doors, as well as along the foundation and under the eves of the roof ( see methods ). Researchers are also evaluating the repellents (e.g., camphor and menthol) to prevent beetles from entering buildings (Koch, 2003).

    Mechanical: Once the beetles enter a building, they can be removed manually or by sweeping or vacuuming. If a vacuum is used, it is advised that a stocking be place over the distal end of the vacuum hose to prevent beetles from passing into the holding container of the vacuum ( see methods ). In addition, traps (primarily black light traps) are available for removineg H. axyridis once they enter a building ( see methods ), but the efficacy of these traps remains uncertain.

    Adriaens et al. (2003) state that, "H. axyridis preys mostly on tree-dwelling hemipteran insects such as psyllids, scale insects and aphids". In addition, H. axyridis will also feed on immature stages of other Coleoptera and Lepidoptera, and plant material such as pollen and injured fruits (Koch, 2003).
    Harmonia axyridis may produce up to 1,642 to 3,819 eggs per female over their entire life span, at a rate of about 25 eggs per day. Eggs are typically laid in clusters of 20 to 30 eggs (Koch, 2003).
    Lifecycle stages
    Harmonia axyridis undergoes a holometabolous life cycle (meaning those insects that undergo a complete change i.e., complete metamorphosis) going through the egg, four larval instars, pupal and adult stages. Studies show that temperature has an effect on the adult weight and the rate of development of the stages. The diet of the beetle is also known to have an effect on larval development (Koch, 2003). The results of a study (LaMana and Miller, 1998) show that at 26º C on a diet of the pea aphid Acyrthosiphon pisum, the mean duration of each stage is as follows: egg 2.8 days, first instar 2.5 days, second instar 1.5 days, third instar 1.8 days, fourth instar 4.4 days, pupa 4.5 days. Koch (2003) states that adults typically live for one to three months, but may live up to three years.
    Reviewed by: Dr. Etienne Branquart, Belgian Biodiversity Platform (SPO) Ministere de la Region Wallonne. Belgium
    Dr. Robert Koch, Department of Entomology, University of Minnesota, USA
    Principal sources: Adriaens et al. 2003 The Multicolored Asian Ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), a threat for native aphid predators in Belgium?
    Koch, R.L., 2003. The multicoloured Asian lady beetle, Harmonia axyridis: a review of its biology, uses in biological control and non target impacts.
    Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
    Last Modified: Monday, 29 August 2005