Lambert Smiths INSECTA

The Harlequin - a destructive alien ladybird

The many species of pretty South African ladybirds have always been a firm favourite amongst gardeners and nature lovers. The very high esteem in which these little beetles are held is further emphasised by their delightful Afrikaans name "Liewenheersbeesies" which directly translated means "Dear Lord’s bug". The reason for the popularity of these insects is to no small degree due to their ability to hunt down and eat aphids (plant lice), mites, thrips and other small insect pests which would otherwise damage our food and ornamental plants.

Ladybirds are beetles from the beetle family Coccinelidae and although some species from the sub-family Epilachninae are herbivores (plant eaters) and can be agricultural pests most are predacious and serve a valuable natural biological control function as eradicators of many insect pests. For this reason their presence is to be encouraged and a number of species have even been imported to aid in pest control. An aggressively invasive, unwanted and destructive species from beyond our borders is now however being found in South Africa in alarming numbers and poses a very real danger to our indigenous ladybird species and insect biodiversity in general.

The little beetle Harmonia axyridis commonly known as the Harlequin Ladybird and also sometimes called the Multi-coloured Ladybird or Asian Ladybird which has its roots in Central and East Asia has been referred to as the most invasive ladybird on earth. Originally imported into America and Europe ( France, Belgium, Holland) for the biological control of Aphids. It has proved to be a biocontrol disaster and has wreaked havoc amongst crops and indigenous insects in a number of countries. It is especially fond of grapes and consequently presents a serious threat to the wine industry. It not only damages the grapes by feeding but can contaminate the grape harvest to the extent that the fruit can no longer be used for the production of wine. In South Africa these ladybirds have now been found in the Eastern and Western Cape, KwaZulu Natal, Mpumalanga and many parts of Gauteng.

What makes this ladybird particularly ominous is its unappeasable appetite. Like other ladybirds it eats aphids but when these become scarce it looks to other insect species. It will devour many other smaller insects such as lacewings which is a valuable insect the larvae of which is also predacious on a number of insect pests. The larvae, pupa and eggs of moths and butterflies, many of them valuable pollinators as well as that of other small beetles such as other indigenous ladybird species are also in danger of being eaten. When live prey is in short supply it will satisfy its appetite on fruit, pollen and plants. Harlequins are cannibalistic and will even turn on their own sort and eat each other when other food sources run out.

The ravenous and indiscriminate feeding behaviour of these ladybirds are capable of damaging the balance of entire eco-systems and present a very real danger to indigenous insect fauna some of which could conceivably be entirely decimated in certain areas if the Harlequins are allowed to get out of control. They are prolific breeders and form large colonies. In some areas they have already been found breeding in their millions and Western Cape farmers report vegetation being ravaged, grapes spoiled and fruit trees being killed by the ladybirds.

Harlequins have a large number of colour variations

At first glance Harmonia axyridis may look like any other ladybird. They are anything from about five to eight millimetres in length, round to slightly oval in shape and shiny in appearance. Their overall colour can vary from yellow through a dull yellow, almost pumpkin-colour, to a deep red. While some have no markings others may have varying numbers of black spots, anything from 1 to 19 on the elytra (wing cases). Harlequins have a large number of colour combination variations within a particular species which serves to confuse identification for the layman. It is quite possibly this peculiarity that led to the insect being named a Harlequin Ladybird.

The most distinguishing feature of the Harlequin ladybird which clearly differentiates it from other ladybirds can be found in the black marking on the pronotum (the hardened area between the head and wing cases (elytra) just behind the head). Typically this mark forms the letter "M" when the insect is viewed from behind. On both sides of the "M" will also be found two large white blotches which give the appearance of "ears". When looked at from the from the front a white "V" can be seen. It must be noted that in some of the colour morphs these characteristic "M" and "V" markings may be made up of broken dots or may be difficult to distinguish. However, Harlequins usually congregate in groups and there will always be at least one specimen that is easily identifiable. There is no indigenous species with this particular combination of markings which can almost be considered as the Harlequins "signature". There are also other variations of Harlequin ladybirds which differ from those described above, for example there is one that is entirely black, but fortunately these have not yet been found in South Africa.

During the warmer months Harlequins inhabit grasslands, orchards and gardens and if present can be found on almost any type of foliage. During the winter months they hibernate and can often be seen resting on the walls of buildings, sometimes in thousands. They also tend to find their way indoors where they will attach themselves to walls or other surfaces. They are capable of biting if handled carelessly and also extrude a foul smelling yellowish liquid which can stain painted surfaces as well as curtains and other fabrics. In some countries they are considered a serious household pest as dwellings are often invaded by thousands of ladybirds.

The really bad news is that there is at present no effective measure available for controlling the Harlequin invasion. Generalised spraying with insecticide is not an option as any insecticide which kills the Harlequins will equally kill indigenous ladybirds and other beneficial insects. Various options such as the possibility of introducing a nematode or a fungus which attacks only this particular species of ladybird is being researched internationally on an ongoing basis. At the International Congress of Entomology which was held in Durban during 2008 nine countries had representatives dealing with the Harlequin Ladybird problem. Riaan Stals an eminent entomologist and beetle expert at the National Collection of Insects of the South African Agricultural Research Council in Pretoria was appointed ad hoc representative for South Africa.

Although this suggestion is of no value agriculturally if Harlequins are found in or about the home an effective and ecologically safe way to kill them is to shake or scrape them into a small container containing a little paraffin, turpentine or alcohol (you can try that 12 year old single malt you have in your liquor cabinet but methylated spirits works just as well).

The first established colony of Harmonia axyridis was officially recorded in September 2004 in the southern Cape. Since then they have rapidly spread to many other parts of the country. Input from the general public is essential in tracing the invasion progression and invasion biology of this insect. All sightings of the ladybird are recorded and mapped by the Plant Protection Research Institute of the Agricultural Research Council. This information assists in following the movement and establishment of invader colonies. Ongoing monitoring of the Harlequin is essential before it gets out of control and starts to annihilate our own insect fauna.

Join in and assist with the Harlequin Watch. If you see a Harlequin Ladybird or a ladybird which you suspect may be a Harlequin anywhere in Southern Africa please contact me (Lambert Smith) and I will forward the information to the relevant authorities. Photo’s will also be very welcome especially if you are not sure of the identification. All emails will be acknowledged.  What we need is the following:

1. Your name (optional)

2. Date of sighting

3. Location of sighting – town/city, area, province

4. Approximate number of Harlequins seen

5. Photo if possible – note that by submitting a photo you are also agreeing to it being published on this website if necessary.

Please remember your participation can be very valuable. Help to stamp out this alien invasion!

Text and photographs copyright Lambert Smith.

© COPYRIGHT Lambert Smith, 2010