Siberian scientists have studied a group of "street" aphids from the genus Pemphigus betae that damage poplars in Eastern Siberia, as reported by the press service of the Siberian Federal University. Pemphigus has the ability to form on plants the so-called "galls" – a kind of swelling growths on leaves and shoots. Scientists are confident that their research will help not only fill in the gaps in the description of the gall aphid fauna of the Siberian region, but also understand how they build connections with trees. This will be the key to finding a way to protect urban green spaces from such pests. The article was published in the Journal of Asia-Pacific Biodiversity.

Pemphigus betae is a species of social insects with a complicated development cycle. They create formations or the so-called galls on the leaves, petioles and young shoots of poplars. These galls serve as a kind of home for aphids, where they live and feed. Pemphigus betae has settled throughout the entire northern hemisphere, where poplars grow which are their favorite food, and some species have even penetrated into the southern hemisphere. It is believed that this group of insects evolved along with their food plants - poplars, and their supposed homeland is the Mediterranean and East Asia.

“There are a lot of aphid species in the world; hundreds of them are known to each resident of dacha as the "garden" ones. Most often, they live in colonies openly on the leaves and shoots of plants. But as for aphids from the genus Pemphigus betae, there are no more than 80 species all over the world. Those which live in “communes” in “houses”, or galls on poplars, are even fewer - only 45 species “ - says Natalia Kirichenko, a senior researcher at the VN Sukachev Institute of Forest FRC KSC SB RAS and Siberian Federal University.

It would be more correct to call this poplar species “street” aphids rather than “garden” ones as they are associated with urban poplar plantings and forest belts. Some species of these insects, due to their exceptional fertility, are large in number and can be significantly harmful. It is due to their activity that the tree leaves fall earlier and young shoots of poplars dry up.

It is interesting that insects change their "summer" and "winter" refuge - the summer generations of Pemphigus betae live in galls on poplars, and the autumn ones most often develop on herbaceous plants. In the latter case, aphids can become serious pests. Basically, they are dangerous for industrial crops, but they can also be transferred to garden crops. Some Pemphigus species are known to be serious pests of lettuce, carrots, and sugar beet in France, Germany and Italy.

"We are planning to study the life cycle and unique social formations of Pemphigus aphids, ways of their dispersal and introduction to our region. A detailed study of the trophic relationships of pests with host trees is also necessary. All this will help us to "grope" for possible ways to deal with the harmful Pemphigus betae. A separate fundamental task for us is to investigate the ability of such aphids to form a “house” - gall, ” says a co-author of the article, junior researcher at the V.N. Sukachev Institute of Forest SB RAS, Nikita Babichev.

One of the tasks facing entomologists from Siberia is to create a "DNA library" of Pemphigus betae. Molecular genetics will make it possible to obtain species-specific genetic characteristics, which would allow one to accurately determine the species of aphids at any stage of development. These libraries will also help to investigate the relationship between the aphid species in different parts of our planet. According to the molecular genetic codes of the species, it will be possible to learn not only about the distribution ways of Pemphigus species, but also to establish the areas which these miniature pests were brought from.

To date, scientists of the Siberian Federal University and V.N.Sukachev Institute of Forest have compiled a detailed review of gall-forming aphids of the genus Pemphigus betae for most areas of Eastern Siberia. The authors provide new information on the distribution of Pemphigus betae in the world and especially in the Asian part of Russia, as well as on their trophic connections and harmfulness. For most species, illustrations of galls are given, whose external characteristics allows recognizing the species of these aphids.

Scientists say that they have already established the species diversity of Pemphigus betae in the south of the Krasnoyarsk Region and north of Khakassia, and now they are planning to investigate in detail the areas of Transbaikal. The aphid habitat in Western Siberia, including the area bordering Kazakhstan, also needs to be clarified.