Alexey Bibin
An entomologist and a senior researcher at the Caucasian Nature Reserve
The Russia’s southern cities are attacked by swarms of predatory ‘harlequin’ ladybugs (Harmonia axyridis). In the Krasnodar Territory, large numbers of ladybugs are infesting homes and buildings in many cities. In early July, thousands of the ‘harlequin’ ladybugs were seen on the rocks, buildings and plants in Anapa, and later on, they began attacking the townspeople and tourists. A seemingly harmless ladybug’s bite can cause an allergic response in humans. However, the Ministry of Natural Resources and Ecology of Russia considers the fears of the invasion of ‘harlequin’ ladybugs’ to be exaggerated. “We are going to order a scientific study to be conducted by the Russian National Research Institute for Silviculture and Forestry Mechanization (VNIILM) to investigate this problem and, accordingly, understand how to deal with it. In the media, the importance is often exaggerated. Forests are always sick. Anyone who has a dacha (summer country house) understands very well that when the dacha season comes, fight against insects (the so called ‘pest control’) is required every day against small beetles, insects or slugs. The situation is the same in the forest, the same biosphere and microclimate are there. We are sure that the problem is not as huge as it is shown in the press. We are working on solving the problem, and as soon as we understand its cause, we will determine how to deal with it,” says Irina Makanova, Director of the Department of State Policy and Regulation in the Protected Areas Development at the Ministry of Natural Resources. The scientists are sure that ‘harlequin’ ladybugs do not pose a great danger. Alexey Bibin, an entomologist and a senior researcher at the Caucasian Nature Reserve, tells where these unusual insects came from and if there are ways to get rid of them.
- First of all, please tell us where did the ‘harlequin’ ladybugs come from? Recently, many harmful insects have been brought to the Krasnodar Territory ...
- These ‘harlequin’ ladybugs are really invasive species. But they were brought to the southern Russia more than half a century ago, not in recent years. And this is a vivid example of how ‘we wanted to do the best, but failed as always’. Harmonia axyridis ladybugs came to the Caucasus in the 1930s from the Far East, they are normally native to the Asian part of our country, Korea, and China. These insects were used as a natural enemy in the fight against aphids (Aphididae) and other pests. They were also brought to other countries. However, ‘harlequin’ ladybugs have acclimatized and begun to spread around the world. Today, the Harmonia axyridis is one of the most famous invasive buggy pests in the world.
- Why are these insects dangerous?
- Naturally, any insect outbreak is an ecosystem load. The appearing new mass predator pests cannot but affect the entomofauna of the Caucasus. First of all, they are a threat to the local ladybugs that do not compete well with the newcomers. In addition, the ‘harlequin’ ladybugs are capable of damaging fruit trees and grapes, and therefore, they can damage the Caucasian fruit growing and winemaking industry. Ladybugs’ bites can cause allergy in humans.
- Why do insect outbreaks happen?
- It’s a natural process, especially for invaders. At this point, they still do not have natural enemies and diseases, and nothing can prevent ‘harlequin’ ladybugs from spreading further. But, a sharp increase in their number is also characteristic of many native species. As a rule, this correlates with weather conditions. For example, this is the case of ‘harlequin’ ladybugs. In cold winter, they hide in dry rooms, these can be attics of houses, sheds, and the like. And if the winter is warm enough, (in the normal habitat of these Harmonia axyridis ladybugs, it can be down to minus 40 degrees Celsius), more ‘harlequin’ ladybugs can come out of hibernation and are able to give more offsprings. Accordingly, this results in a surge in their population.
- What are the ways to fight ‘harlequin’ ladybugs?
- Almost none. If some chemicals are used, they can destroy the local ladybugs, which, in turn, have a certain place in the ecosystem, and their destruction would upset the balance in the biocenosis.
- Recently, the problem caused by the insect outbreaks has been very acute in the Kuban. For many years, there has been a fight against box tree moths (Cydalima perspectalis). But this year, a decision was taken that various chemicals can be used at the protected areas to keep these insects down. To what extent did this solve the problem?
- The decision to use chemicals in the protected areas was made, but by this time, there is practically no box trees left. Considering that the box tree moths destroyed almost all natural box forests, the pests had no enough food base and the number of box tree moths greatly decreased. Despite all the existing norms and regulations, the Adygea’s authorities who supported the decision (while going through all the bureaucratic delays) to protect box trees and managed to save five hectares of these unique box trees. The present solution is a reserve and protective stock for the future, which, we hope, will help recover box forests. It also remains to hope that as a result, natural enemies of the box tree moths will appear in nature, which can restrain their number.
- A huge problem for Sochi is the palm weevils (Rhynchophorus palmarum) that destroy palm trees ...
- We can only accept the fact that there will be fewer palm trees in Sochi. The matter is that these pests “kill” the plant from inside, it is impossible to apply the spraying method, for example, from a helicopter, besides, palm trees are located in the city area. To destroy the weevils, special injections are used but they must be given to each tree. And it’s expensive and very labour intensive.
- In the Caucasus, there is another misfortune - chestnut gall wasps (Dryocosmus kuriphilus). What are the chances of protecting and preserving such rare plants as chestnut trees?
- Chestnut trees in the Caucasus’ forests became much weaker due to cryphonectrian necrosis (with Cryphonectria parasi), the chestnut gall wasps have just exacerbated the situation. There is a way of dealing with it used in Europe and Asia - these are hymenoptera: parasitoid wasps Torymus sinensis that penetrate the galls and destroy the chestnut gall wasps. A trial batch of Torymus sinensis was brought to the Caucasian Reserve and the Sochi National Park to protect the forest. Today, we hope that Torymus sinensis wasps have adapted and will begin spreading.
- Most of the invasive insects came to Sochi during the Winter Olympic Games. What systemic changes are needed to prevent this from happening again?
- Since the 2014 Winter Olympics, we have seen new invasive insects appearing every year. Last year, for example, five species of beetles new to Russia were found at the Sochi Dendrological Park “Southern Cultures”. Fortunately, they are saprobes, they feed on the products of plants’ decay and do not pose a danger. After the city received a large influx of tourists, the port was built and the development of cargo traffic began, the number of ‘imported’ insects naturally increased. Therefore, strengthening the work of the quarantine service is the only way to solve the problem. Unfortunately, there are gaps in the Russian legislation in this regard.
