There are no known troglobiotic hymenopterans, although a few species regularly occur in caves, usually for an inactive phase of their life-cycles. During a recent faunistical survey of the invertebrate fauna of Bakony Mountains’ caves (Hungary) several Hymenoptera specimens were collected in hypogean environments. In this paper we report the results of the survey regarding Hymenoptera. Although the Hymenoptera material was small in numbers, they provided valuable faunistical data: very rare or rarely collected species were found, and 5 taxa are first reported from hypogean environment. Aclastus longicauda Horstmann (Ichneumonidae: Cryptinae) was found new to the Hungarian fauna, considerably extending the distributional area of this species that has been known only from Northern Europe so far. Our local results clearly indicate that, both at local and world-wide level, research focusing on the usually overlooked Hymenoptera fauna of caves will certainly provide valuable faunistical, distributional and biogeographical data.

Aclastus, Ichneumonidae, Braconidae, Proctotrupidae, Embolemidae

There are no known troglobiotic hymenopterans, although a relatively few species are known to regularly occur in caves, usually for executing an inactive phase of their life-cycle. From the hundreds of thousands described hymenopteran species only about 200–250 species have been reported to be associated with hypogean environments (see e.g. Decu et al. 1998, Moldovan 2004). Presumably this number is greatly underestimated due to the following reasons: (i) usually zoologists studying troglobiotic animals are not specialized in Hymenoptera, hence do not consider to collect and/or identify the hymenopterans, as they are not troglobiotic animals; (ii) Hymenoptera specialists usually do not collect in hypogean environments; and (iii) even if there is collected material, there are relatively few specialists who are able to reliably identify the specimens of the most commonly collected, very diverse groups of parasitoid wasps. For these reasons, the literature on Hymenoptera of cave environments is rather scarce and sporadic. The aim of this work is to contribute to the knowledge the Hymenopteran fauna of Middle European caves, and to facilitate future studies by drawing the attention to this poorly discovered topic.

In 2009 the Bakony Museum (BM) of the Hungarian Natural History Museum (HNHM) and the local caver clubs started to investigate the cave fauna of the Bakony Mountains (Veszprém County, Hungary). Some of these caves were never studied before by zoologists. The results have already been reported in some parts (see e.g. Szabó et al. 2013, Disney 2014, Novák and Kutasi 2014). Several Hymenoptera specimens were also collected in these hypogean environments; in this paper we report the results of the survey regarding Hymenoptera.

Between 2009 and 2012 invertebrates were collected in five caves in the Bakony Mountains. The studied caves belong to the authority of the Balaton-felvidéki National Park, and they are partly open to the public (Fig. 1).

Figure 1.

Location on the studied caves in Hungary: 1 Csodabogyós Cave (Balatonederics) 2 Pokol Hole (Kapolcs) 3 Lóczy Cave (Balatonfüred) 4 Kőlik Cave (Szentgál) 5 Takó Cave (Veszprém).

The Csodabogyós Cave (46°47.822'N; 17°21.873'E, ca 400 m, investigated between 17 December 2009–13 January 2011, and 22 July–5 October 2011) is situated at Balatonederics, in the Keszthely Mts. which is part of the Bakony Mts. The cave was formed in the Late Triassic period in Ederics Limestone formation. It is a 5200 m long and 121 m deep cave with a multi-level system of fissures. The cave chambers are decorated with various dripstone formations, therefore it has been strictly protected since 1992 (Kárpát 2003, Anonymous 2012).

The Lóczy Cave (46°58.140'N; 17°52.409'E, ca 250 m, investigated between 25 November 2010–26 March 2012) is near Balatonfüred. It was discovered in 1882. The 154 m long and 15 m deep cave was formed by upwelling thermal water in Füred Limestone in the Late Triassic period, and it is strictly protected since 1982 (Hazslinszky 2003, Anonymous 2012). The Takó Cave (47°11.702'N; 17°54.974'E, ca 350 m, investigated between 6 March 2009–30 January 2010) is near Eplény; it is a 60 m long limestone cave (Anonymous 2012).

The Kőlik Cave (47°06.105'N; 17°44.892'E, ca 370 m, investigated between 25 March 2011–25 October 2012) is situated at Szentgál; it is 420 m long and 39 m deep. This limestone cave is strictly protected since 1993 (Anonymous 2012). The Kapolcsi Pokol Hole (46°56.823'N; 17°35.302'E, ca 270 m, investigated between 28 March 2012–22 May 2013) is a 56 m long tectonic basalt cave. The thick basalt blocks the seeping water, which therefore emerges as a spring.

The invertebrates were collected by 250 cm³ volume pitfall traps filled with ethilen-glicol in each cave. Traps were situated from the entrance of the caves till the last approachable parts; average number of traps was 15 per caves, and they were working for a year. Stinking cheese was used as bait material.

The collected Ichneumonidae, Proctotrupidae and Embolemidae material was identified by the first author using a Nikon SMZ645 stereoscopic microscope; a specimen belonging to Braconidae was identified by Dr. Jenő Papp. The identification was based on keys provided by Hellén (1941), Constantineanu (1959), Townes et al. (1965), Townes (1970, 1971), Pschorn-Walcher (1971), Horstmann (1980), Townes and Townes (1981), Wahl (1993), Achterberg and Kats (2000), and Broad (2011). Earlier records of the species in the Hungarian fauna were checked in Mocsáry (1886, 1897), Olmi (1999), Papp (2005), and Yu et al. (2012). The material is deposited in HNHM.

Below we list the species found in the caves of Bakony Mountains. Taxa are listed in alphabetical order. Distributional and biological and/or taxonomical remarks are given following the collecting data of each species. English translations of the names of rooms and branches within the caves are given in brackets. Distance of the collecting site from the cave entrance is abbreviated as DFE.

Although no troglobiotic hymenopteran species are known, our results suggest that more species are associated with hypogean environment for a shorter or longer phase of their life-cycles than expected. The most probable explanation is that troglobiotic faunistical surveys rarely consider to collect and/or identify the hymenopteran specimens from caves as they are regarded as outsiders of the cave environments. Nevertheless, not only some very rare wasp species (such as Eutanyacra jucunda) were found in the caves of Bakony Mts., but this material greatly extended our knowledge of the geographical distribution of an ichneumon wasp species (i.e. Aclastus longicauda), and 5 hymenopteran taxa were recorded from cave environment for the first time. Our local results clearly indicate that, both at local and world-wide level, research focusing on the Hymenoptera fauna of caves will certainly provide valuable faunistical, distributional and biogeographical data.

The authors are grateful to Tamás Lajos Katona, Zsolt Csermák, Attila Piri, Szilárd John, and Sándor Tóth for their help in the cave collecting work. We thank Ferdinánd Takács, Livia Takács-Szenc, and Attila Piri for additional data on the corresponding caves. We are grateful to Jenő Papp for identifying the Braconidae specimen, and to Dorottya Angyal and Anca Dragu for their help in obtaining relevant biospeological literature. Special thanks are due to the prominently public benefit organization of the Bakonyi Természettudományi Múzeum Baráti Köre for supporting the financial support.