THRIPS GROUPINGS (INSECTA: THYSANOPTERA)
DEPENDING ON THE TYPE OF PLANT COMMUNITY
OF THE JAWORZNICKIE HILLS (SILESIAN UPLAND, POLAND)
W. Sierka, W. Wojciechowski
University of Silesia, Katowice, Poland, E-mail: email@example.com, firstname.lastname@example.org
Key words: Thysanoptera, thrips, zoocenosis, thysanopterocenosis, Poland
В. Сиерка, В. Войцеховский
Университет Силезии, Катовице, Польша, E-mail: email@example.com, firstname.lastname@example.org
Ключевіе слова: Thysanoptera, трипсі, зооценоз, тизаноптероценоз, Польша
Most of the research on thrips conducted in Poland has so far been concerned with the qualitative and quantitative composition of thrips fauna in agrocenoses as well as its influence on the growth of cultivated plants and cropping. The dependence of the species composition of thrips fauna on the structure of plant cover has been investigated by a few polish researches, among others, in xerothermic grass communities, dry-ground forests and thermophilous grass communities.
Relatively little research has been done on thrips living in various plant communities, which encouraged the present study conducted in the Jaworznickie Hills (Silesian Upland, southern Poland), an area representative enough to determine relationships between the structure of thrips associations and plant communities.
The Jaworznickie Hills, geologically highly diversified, cover an area of 510 km2, their average altitude approximates 300 m above sea level. Most habitats potentially suitable for dry-ground forests, beech woods and mixed coniferous forests are now taken over by impoverished xerothermic grasses of the class Festuco–Bromete, arable lands and meadows (Arrhenatherion, Calthion, and Molinion), and pastures (Cynosurion), which degenerate as a result of drainage and transform into grass phytocenoses.
Material for the study was collected in selected plant communities of the Jaworznickie Hills in the years 1998–2000. Detailed analysis (a population profiles) was carried out in seven types of plant communities: I – Tilio–Carpinetum typicum, II – Querco roboris–Pinetum, III – Pruno–Crataegetum, IV – Trifolio–Agrimonietum, V – Koelerio–Festucetum sulcatae, VI – Molinietum medioeuropaeum, and VII – Arrhenatheretum medioeuropaeum.
For particular types of plant communities, Simpson’s species diversity coefficient was calculated (Simpson, 1949).
To determine the similarity of species composition in various zoocenoses, Sørensen’s coefficient was used (Sørensen, 1948).
In order to arrive at a more comprehensive and objective interpretation of the relationships between groups, Sørensen’s formula was additionally modified by substituting the number of species with the number of specimens (Górny & Grüm, 1981). In this way the total mathematical similarity between two sets was established, taking into account the number of individual elements which occurred in both sets.
The results of the analysis of groupings were presented graphically in a dendrogram. Moreover, the data were ordered by means of the principal component analysis (PCA).
During the three-year study in the examined area, 71 thrips species were collected by scooping, of which 53 represented the suborder Terebrantia, while the remaining 18 – the suborder Tubulifera.
Simpson’s species diversity coefficient was found to be highest in continental dry-ground forest and lowest in thermophilous communities on the outskirts of forests.
On the basis of Sørensen’s similarity coefficient, three groups of thrips were distinguished which inhabited specific types of plant communities. Group A comprises thrips of forest communities; group B includes thrips of outskirts of forests, shrub communities and xerothermic grasses; and group C – thrips found in meadow communities. And also the principal component analysis (PCA) produced three distinct types of groupings connected with different plant communities and habitats.
The species composition and proportion of thrips in the studied area are not typical of stable phytocenoses, as they are connected with plant communities to a considerable extent transformed by antropopressure. Changes in phytocenoses result in distortion of the related zoocenoses, which may be reflected in the decrease in the number of species, especially those rather rare, and the emergence of one or two dominant species, which prevail in the structure of the group. In the studied area three dominant species were found: Chirothrips manicatus Haliday, 1836 (connected with grasses), Aeolothrips intermedius Bagnall, 1934 (predacious) and Frankliniella intonsa (Trybom, 1895) (floricolous).
The mathematically calculated pattern of relations presented in the dendrogram and in the PCA graph-three groups of thrips (A, B, C) connected with specific plant communities – is reflected in the ecological analysis. This pertains in particular to group A (forests), where there was a considerable proportion of stenotopic species connected with bark and feeding on fungi (e. g. Hoplandrothrips bidens (Bagnall, 1910) and Phlaeothrips coriaceus Haliday, 1836).
Thus, it appears that the type of plant community is the main factor influencing the formation of thrips groupings in the area of the Jaworznickie Hills; however, the development of the plant community depends on many biotic and abiotic factors.
The study of species composition of thysanopterous fauna of various plant communities in Poland and similarities between insect groups connected with these communities is still under way. Detailed quantitative analyses of Thysanoptera contribute to our knowledge of long-term processes and spatial and temporal interactions within thrips fauna. To make such comparisons more reliable, further research on thrips is needed both in other regions of Poland and in Europe.
Zoocenosis — 2005
Біорізноманіття та роль зооценозу в природних і антропогенних екосистемах: Матеріали ІІІ Міжнародної наукової конференції. – Д.: Вид-во ДНУ, 2005. – С. 305-307.