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THE MONITORING OF BRACONIDAE IN THE TERRITORY INFLUENCED BY THE HYDROELECTRIC POWER STRUCTURES GABCIKOVO

#### Jozef LUKAS

Institute of Zoology, Faculty of Natural Sciences, Comenius University, Mlynska dolina, B-2, 84215 Bratislava, SLOVAKIA

CONCLUSIONS Putting the Cunovo reservoir into operation caused an increase of the ground water level in the monitored areas between Bratislava and the beginning of the by(pass canal. In spite of this, the monitored areas 1 and 2 retained their original character. There can be found forest-steppe biotopes with valuable xerothermophilous fauna. Monitoring areas under the outlet canal (area 7 and 8) are influenced little by the hydropower water structures. The first indications of aridisation can be noticed here, too. The most affected monitoring areas are in the diversion territory, where important hydrological changes arise. However, this reality was disclosed differently in the localities 5 and 6, where (similarly as with epigeical bugs) the highest qualitative and quantitative representation of Braconidae was observed, and evendifferently in the localities 3 and 4, which are mostly affected from the point of view of occurrence of the model group. An improvement of the present state can be reached by increasing the ground water level and strictly controlling the export of wood material from the flood-plain forest.

#### INTRODUCTION

Up until the present, minimal attention was paid to the study of Braconidae in the Danubian Lowland area, although they belong to the most important groups of Hymenoptera. In the period before and after filling the hydropower water structures, we observed a representation of the Braconidae species in the herb layer at 8 monitoring areas:

1. Ostrov Kopac
2. Ostrovne lucky
3. Dunajske kriviny
4. Bodicka brana,
5. Kralovska luka
6. Istragov
7. Sporna sihot
8. Stary les.

Vegetation conditions were considerably different at individual localities, which also resulted in a different qualitative and quantitative representation of Braconidae.

#### MATERIAL AND METHODS

Research of Braconidae was performed from May to October of 1990-1994. For collecting samples from vegetation we used an entomological net with a diameter of 37 cm. We tried to take samples from the dominant spectrum of vegetation species in the monitoring stands. A part of the Hymenoptera was bred under laboratory conditions from different stages in their hosts. The nomenclature according to Sedivy et. al. [4] was used.

#### RESULTS

A total of 143 species of Braconidae belonging to 16 families were found in the studied area. Their list and occurrence in the individual localities is in Table 1.

#### Ostrov Kopac

We have visited this and the next locality since 1993. Samples were collected from the herb layer of the forest-steppe vegetation community Crataegetum danubiale. The area has a xerotherm character, which also responds to the observed spectrum of the species of Braconidae, with a dominant representation of parasitoides of butterflies. The increase of humidity in the observed area in 1994 was reflected in the structure of taxocoenoses of Braconidae. In contrast to the previous year, there was a higher proportion of species parasitising on Diptera. In total, we recorded 48 species belonging to 14 subfamilies (Tab. 1).

#### Ostrovne lucky

Collection of samples from this monitored area was performed on a forest-steppe of the association Crataegetum danubiale. The locality has a similar character as the locality Ostrov Kopac island, and the observed species spectrum of Braconidae is quite similar too. Here prevail larvae of butterfly parasitoids, yet higher proportions. Parasitoides of beetles are represented here by less than half, which is directly connected to the higher species diversity of xylophages in Ostrov Kopac, than in this territory (Fig. 1). More of the observed species in the monitored areas 1 and 2 are indicators of xerothermic biotopes, and therefore deserve protection. Their presence on Kopac Island and Ostrovne lucky confirms that these territories still belong to valuable places of occurrence of rare animals, and this is despite many harmful influences.

#### Dunajske kriviny

We decided to use a margin of residue of flood-plain forest and a forest glade (Salici-Populetum) for the observation of Braconidae. Here in the herb layer Urtica sp. and Rubus sp. prevailed. In 1994 only 35% of individuals were captured by quantitative sampling on this stand, as compared to the situation observed in 1992, when there was a relative abundance of water in the area. During 1993 this locality was dry, and this situation continued in 1994 too, which was negatively manifested by the qualitative and quantitative representation of Braconidae. In 1990-1992, before the diversion of the Danube, the families Alysiinae and Opiinae, parasites of Diptera, were dominantly represented there, as they prefer moisture biotopes. In 1993, and mainly in 1994, their qualitative and quantitative representation decreased, and parasitoides of butterflies, typical for drier biotopes, began to dominate (Fig. 2). The locality changed its original character as a consequence of aridisation and the impact of the natural succession of herbaceous communities.

#### Bodicka brana

The collection of samples from this monitored area was performed at the margin of a flood-plain forest, close to the stream of the Danube. Although this territory is characterised by many river arms, which is the merit of the sufficient amount of water in this area. Gravel holes, which can be found in a longer distance from them, dry up and are overgrown with vegetation. Ooriginally this area was mostly represented by the families Alysiinae and Opiinae, which are continuously substituted by Microgastrinae and Braconinae, what testifies to the drier character of the territory, in comparison to the previous years (Fig. 1). From the localities observed since 1990, this is the second poorest locality from a qualitative as well as quantitative point of view.

#### Kralovska luka

We have chosen a monitoring stand positioned in a deforested section, between the flood-plain forest and the dike, in this monitored area. In the herb layer a large representation of the species of the family Apiaceae, with flowers offering a suitable trophical basis for imagoes of Hymenoptera, could be found. This had a positive influence on taxocoenoses of Braconidae. Dominant in the observed area arerepresentatives of the subfamilies of Braconinae, Microgastrinae and Alysiinae with eurytopic species Bracon erraticus, Microgaster tuberculifer and Dacnusa pubescens. Braconidae parasies of the order Lepidoptera which prefer dryer biotopes prevail at this monitoring stand (Fig. 1).

#### Istragov

The monitored territory of Istragov is a large area with many river arms. We observed two different biotopes in this territory:

1. The margin of the flood-plain forest and the dike with a dominant overgrowth of Daucus carota.
2. The flood-plain forest (Salici-Populetum), where Anthriscus sylvestris and Urtica sp. were prevailing on the herbal floor.

During a period of three years the richest community of Braconidae was observed in this locality (Tab. 1). Here the subfamilies of Alysiinae, Braconinae, Helconinae, and Microgastrinae were dominantly represented, and the species Blacus ruficornis, Dacnusa pubescens and Phaenocarpa picinervis reached the highest abundance. While comparing the two monitoring stands, differences in the species composition were observed. At monitoring stand No. 1 species parasitising on the order of Lepidoptera prevailed, while at monitoring stand No. 2 parasitoides of the order Diptera, requiring rather more humid biotopes, were highly represented. Although an apparent deterioration of the hydrological conditions arose in this locality, a negative trend on the Braconidae cannot meanwhile be observed. We explain the given reality through the existence of a diversity in the herb layer in the poplar flood-plain forest. Diversity creates good climatic conditions for the life and development of Braconidae. The felling of trees and the harvesting of the flood-plain forest, which appears rather intensive in this locality, may have a negative impact in the future.

#### Sporna sihot

In this locality, we have chosen a monitoring stand placed at the margin of the flood-plain forest, where Urtica sp. and Impatiens nolitangere prevailed in the herb layer. During the study period no important changes occurred, neither in the qualitative nor quantitative representation of Braconidae. We explain this by the presence of a diversity in the herb layer supplying food for the imagoes of Hymenoptera. On the other hand, the absence of some hygrophilous species in 1994 could indicate an initial phase of the aridisation of this area.

#### Stary les

We have visited this study area since 1993. The area consists of forest glades (lighting( and a flood-plain forest margin (Salici-Populetum), positioned close to a dead river arm, approximately 200 m from a dike. The water level varies in relation to the water level changes in the main stream of the Danube. The herb layer is monotonous, with a considerable occurrence of Rubus sp., what corresponds also to a poor taxocoenoses of Braconidae. Under the influence of the extreme aridity in 1994, species parasiting on caterpillars were prevailing, opposite to the previous year, when parasitoides on beetles were most abundant (Fig. 1).

#### REFERENCES:

  [1] Achterberg, C., 1976: Revisie van de tribus Blacini (Hym., Braconidae). - Wagenningen-Fa. Ponsen - Looijen, 322 pp.

  [2] Fischer, M., 1972: Erste Gliederung der palaarktischen Aspilota Arten (Hym., Braconidae). - Pol. Pis. ent., 42: 323-459.

  [3] Fischer, M., 1973: Opiinae I., Hymenoptera, Braconidae. - Das Tierreich, Lief. 71, W. de Gruyter, Berlin-New York, 620 pp.

  [4] Sedivy, J., et. al., 1989: Check list of Czechoslovak Insects III (Hymenoptera). - Acta faun. ent. Mus. nat. Pragae, 19: 27-44.

  [5] Tobias, V.I., 1986a: Opredelitel nasekomych evropejskoj casti SSSR. Tom III., pereponcatokrylyje 4. cast. - Nauka, Leningrad, 500 pp.

  [6] Tobias, V.I., 1986b: Opredelitel nasekomych evropejskoj casti SSSR. Tom III., pereponcatokrylyje 5. cast. - Nauka, Leningrad, 308 pp.

Table 1. Systematical overview of Braconidae found in the studied areas

Species | Study plot
--- | ---
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8
Ontsira antica (Woll.) | + | - | + | - | - | - | - | -
Rhaconotus aciculatus Ruthe | + | - | - | - | - | - | - | -
Dendrosoter protuberans (Nees) | + | - | + | - | - | - | - | -
Heterospilus ater Fi. | - | - | - | - | + | - | - | -
Spathius curvicaudis Ratz. | + | - | - | - | - | - | - | +
Spathius exarator (L.) | + | + | + | - | - | + | + | +
Ecphylus silesiacus (Ratz.) | + | - | + | - | - | - | + | +
Colastes braconius (Hal.) | - | - | + | - | - | + | - | -
Rhyssalus clavator Hal. | + | - | - | + | - | - | - | +
Hormius moniliatus (Nees) | - | + | - | - | - | + | + | +
Gnaptodon pumilio (Nees) | - | - | - | + | - | - | - | -
Isomecus nominator (Fabr.) | + | + | - | - | + | - | - | -
Isomecus tentator (Rossi) | - | + | - | - | + | - | - | +
Coeloides filiformis Ratz. | - | - | - | - | + | - | - | -
Bracon anthracinus Nees | - | - | - | + | - | + | - | +
Bracon atrator Nees | - | - | - | + | - | + | - | -
Bracon epitriptus Mrsh. | + | - | - | - | + | + | + | +
Bracon erraticus Wesm. | + | + | + | - | + | + | - | -
Bracon fulvipes Nees | - | + | - | - | - | - | - | -
Bracon intercessor Nees | + | + | - | - | - | + | + | +
Bracon obscurator Nees | + | - | + | + | + | - | + | +
Bracon osculator Nees | - | - | - | + | + | - | + | -
Bracon pineti Thoms. | + | - | - | - | - | - | - | -
Bracon picticornis Wesm. | - | + | - | - | + | + | - | -
Bracon nigratus Wesm. | - | + | + | - | - | - | + | -
Habrobracon hebetor (Say) | + | + | + | + | - | + | + | +
Pigeria piger (Wesm.) | + | + | - | - | + | - | + | -
Aleiodes geniculator (Nees) | + | - | - | - | - | - | - | -
Aleiodes bicolor (Spin.) | - | - | + | - | + | + | + | +
Aleiodes cruentus (Nees.) | - | - | - | - | - | + | - | -
Aleiodes ductor (Thunb.) | - | - | + | - | - | - | + | -
Aleiodes tristis Wesm. | - | - | - | - | + | - | - | -
Ademon decrescens (Nees.) | - | - | + | - | - | + | - | -
Opius austriacus Fi. | + | - | - | - | - | - | - | -
Opius ambiguus Wesm. | - | + | - | + | + | - | + | -
Opius crassipes Wesm. | - | - | + | - | + | - | + | +
Opius exiguus Wesm. | - | - | + | - | + | - | + | +
Opius levis Wesm. | - | - | + | + | - | - | + | -
Opius laetatorius Fi. | - | - | - | - | + | - | - | -
Opius ochrogaster Wesm. | - | - | - | + | + | + | + | -
Opius pallipes Wesm. | + | + | - | + | - | - | - | +
Opius propodealis Fi. | - | - | - | - | - | + | - | -
Opius rex Fi. | + | - | - | + | - | + | + | -
Opius rudis Wesm. | - | - | - | - | + | - | - | -
Opius tuberculifer Fi. | - | - | - | - | - | - | + | -
Alysia manducator (Panz.) | - | - | + | - | - | + | + | +
Aphaereta ma,jor Thoms. | - | - | + | - | - | + | + | -
Aphaereta minuta (Nees.) | - | - | + | + | + | + | + | -
Aspilota concinna (Hal.) | - | - | - | - | - | + | - | -
Aspilota caudata Thoms. | - | - | - | + | + | + | - | -
Aspilota efoveolata Thoms. | - | + | - | + | - | + | + | -
Aspilota microcera Thoms. | - | - | + | - | + | + | - | +
Aspilota nigricornis (Thoms.) | + | - | + | - | - | - | - | -
Aspilota ruficornis (Nees) | + | - | + | + | - | - | + | -
Aspilota varipes Tob. | - | - | - | + | - | - | + | -
Cratospila circe (Hal.) | - | - | - | + | + | - | + | -
Orthostigma laticeps Thoms. | - | - | + | - | - | - | + | +
Orthostigma mandibulare (Tob.) | - | - | - | - | + | - | - | -
Orthostigma pumilum (Nees) | - | - | - | + | + | - | - | -
Orthostigma sordipes Thoms. | - | - | - | - | + | + | - | -
Pentapleura pumilio (Nees.) | - | - | + | - | + | + | - | -
Phaenocarpa picinervis (Hal.) | - | - | - | + | + | + | - | -
Phaenocarpa eugenia (Hal.) | - | - | - | - | - | + | - | -
Phaenocarpa ruficeps (Nees) | - | - | - | - | - | - | + | -
Synaldis concolor (Nees) | + | - | + | + | - | + | + | -
Synaldis sulcata Fi. | - | - | + | - | - | - | + | -
Trisynaldis conflucta Fi. | - | - | - | - | - | - | + | -
Chorebus gracilis (Nees) | + | + | + | + | + | + | + | +
Chorebus petiolatus (Nees) | - | - | - | - | - | + | + | -
Chorebus resa Nixon | - | - | + | + | - | + | - | -
Coelinius niger (Nees) | - | + | - | - | - | + | + | +
Dacnusa adducta Hal. | - | - | + | - | - | - | - | -
Dacnusa annulata (Nees) | - | - | + | + | + | + | - | -
Dacnusa pubescens (Curt.) | + | + | + | - | + | + | + | +
Dacnusa temula Hal. | + | - | + | + | + | + | - | -
Dacnusa maculipes Thoms. | - | - | - | + | + | - | + | -
Exotela gilvipes (HaI.) | - | - | - | + | - | + | - | -
Polemochartus liparae (Gir.) | - | - | + | - | - | - | - | -
Protodacnusa tristis (Nees) | - | - | - | - | - | + | - | -
Helcon tardator Nees | - | - | - | + | - | - | - | -
Aspicolpus carinator (Nees) | - | - | - | + | - | - | - | -
Diospilus robustus Reinh. | - | - | + | - | - | - | - | -
Diospilus rugosus Thoms. | - | - | + | + | - | + | + | +
Eubazus longicaudis (Ratz.) | - | - | + | + | + | - | + | +
Eubazus parvulus (Ruthe) | - | - | - | + | - | - | - | +
Eubazus rugosus (Ratz.) | - | - | - | - | - | + | + | -
Polydegmon sinuatus Foerst. | - | + | - | - | - | - | - | -
Schizoprymnus emarginatus Snofl. | - | + | + | + | - | - | - | -
Schizoprymnus obscurus (Nees) | + | - | - | - | - | - | - | -
Triaspis aciculatus (Ratz.) | - | - | - | + | - | + | - | -
Triaspis gibberosus (Szepl.) | + | + | - | + | - | - | - | -
Triaspis obscurellus (Nees) | - | - | - | - | + | + | - | -
Blacus exilis (Nees) | - | - | + | - | - | + | - | -
Blacus maculipes VVesm. | + | - | + | - | + | + | + | +
Blacus pallipes Hal. | - | - | - | - | + | + | + | +
Blacus ruficornis (Nees.) | + | + | + | + | + | + | + | +
Macrocentrus collaris (Spin.) | + | + | + | + | + | + | - | +
Macrocentrus marginator (Nees) | - | + | - | - | - | - | + | -
Macrocentrus linearis (Nees) | - | + | - | + | - | + | - | -
Orgilus oehlkei Taeger | + | - | - | - | - | - | - | -
Orgilus pimpinellae Niez. | + | + | + | + | + | + | - | -
Vipio desertor (L.) | + | - | - | - | - | - | - | -
Agathis malvacearum Latr. | - | + | + | - | - | - | - | -
Agathis nigra Nees | - | - | + | - | - | - | + | -
Agathis rufipes (Nees) | - | + | - | - | - | ~ | ~ | ~
Dolichogenidea longicauda (Wesm.) | ~ | - | - | - | + | + | - | -
Dolichogenidea dilecta (Hal.) | + | - | - | - | - | - | - | -
Dolichogenidea emarginata {Nees) | - | - | - | + | - | - | - | -
Pholetesor circumscriptus (Nees) | - | - | - | - | + | + | - | -
Choeras parasitellae (Bouch) | - | - | - | + | + | + | + | -
Apanteles metacarpalis Thoms. | + | + | + | - | - | - | - | +
Illidops butalidis (Mrsh.) | + | + | - | - | - | - | + | -
Cotesia glomerata (L.) | - | + | - | - | + | - | + | -
Cotesia limbata (Mrsh.) | - | - | - | + | + | - | - | -
Cotesia saltator (Thunb.) | - | + | + | - | - | + | - | -
Cotesia spurius (Wesm.) | - | - | - | - | - | - | - | +
Cotesia zygaenarum (Mrsh.) | + | - | + | - | + | - | - | +
Microgaster subcompletus Nees | - | + | - | - | + | - | + | -
Microgaster mandibularis Thoms. | + | - | - | - | - | + | + | -
Microgaster nobilis (Reinh.) | + | - | - | - | - | - | - | -
Microgaster tuberculifer Wesm. | - | - | - | + | + | - | + | +
Mirax rufilabris Hal. | - | - | - | - | - | + | - | -
Chelonus annulipes Wesm. | - | + | - | - | + | - | - | -
Chelonus asiaticus Tel. | - | - | - | + | - | + | - | -
Chelonus inanitus (L.) | + | + | - | + | + | + | - | -
Chelonus scabrator (Fabr.) | + | + | - | - | + | + | - | +
Microchelonus contractus (Nees.) | - | + | - | - | + | + | - | -
Microchelonus retusus (Nees.) | + | + | - | - | + | - | - | -
Microchelonus rimatus (Szepl.) | - | + | - | - | - | - | - | +
Ascogaster quadridentata Wesm. | + | + | - | - | + | - | - | -
Ascogaster ru idens Wesm. | - | - | - | + | - | + | + | -
Ascogaster varipes Wesm. | - | + | - | + | + | - | - | -
Meteorus gyrator (Thunb.) | - | - | - | + | - | + | - | -
Meteorus ictericus (Nees) | + | - | - | - | + | + | - | +
Meteorus versicolor (Wesm.) | - | - | - | - | + | - | + | -
Elasmosoma berolinense Ruthe | + | ~ | - | - | - | - | - | -
Centistes fuscipes (Nees) | + | + | - | - | - | - | - | -
Pygostolus falcatus (Nees) | - | - | + | - | - | - | - | +
Perilitus rutilus (Nees) | - | - | - | + | + | + | + | +
Peristenus orchesiae (Curt.) | + | - | - | - | -c | + | - | -
Dinocampus coccinellae (Schr.) | + | - | - | + | - | + | + | -
Microctonus aethiops (Nees) | - | - | - | + | + | + | + | +
Microctonus secalis (Hal.) | - | + | - | - | + | - | - | -