On the discovery of Arytrura musculus (Menetries, 1859) (Lepidoptera: Erebidae) in Croatia
Arytrura musculus (Menetries, 1859) in Croatia
Toni Koren*, Mladen Zadravec, Boris Lauš
Association Hyla, I. Lipovac 7, HR-10000 Zagreb, Croatia
*Corresponding author: koren.toni1@gmail.com

Abstract
Background and purpose: The moth fauna of Croatia is still insufficiently surveyed. During the last several years, several overviews of the moth fauna for several locations were published and several new species for the country had been found. Only two species from Annexes II and IV of the Habitats Directive are listed for Croatia. A third is known to occur in the country, but has been omitted due to a lack of recent records. Presented here is the first record of a fourth species from the Annexes – Arytrura musculus.
Materials and methods: This survey was carried out on one location in Nature Park Lonjsko Polje, on 17.6.2016. The habitat at the location is typical for the area, consisting of floodplain oak forests with Genista tinctoria. Two pyramidal light traps were used.
Results: One specimen of Arytrura musculus was found. This is a rare and disjunctly distributed species across Eastern Europe. The closest known populations to the Croatian locality are situated in Hungary, 122 and 130 km away.
Conclusions: This species needs to be added onto the list of Natura 2000 species for the Nature Park and for the whole country at the earliest possible convenience. Detailed surveys of the entire Lonjsko Polje Nature Park and other wetland areas in northern Croatia are needed in order to ascertain the distribution, assess the status and assure the long-term conservation of this species in the country.

Key words
Lonjsko Polje; Natura 2000; new country record; distribution; SAC

Introduction
The moth fauna of Croatia, as well as most of the ex-Yugoslavian countries like Bosnia and Herzegovina, Montenegro, and FYR of Macedonia is still insufficiently surveyed. While large parts of the country still remain insufficiently studied, during the last few years new overviews of the moth fauna of several smaller parts of Croatia were published, greatly contributing to the general knowledge about the moth diversity within the country. This mainly includes Krk Island (1), central Istria (2, 3) and Nature Park Kopački Rit (4). Recently several Macroheterocera species were recorded as additions to the country’s rich moth fauna, e.g. Antitype suda (Geyer, 1832) (5), and Chersotis multangula (Hübner, 1803) (6). On the other hand, dozens of Microlepidoptera species are still being recorded as new members of the Croatian fauna (e.g. 7, 8, 9, 10). Still, many unpublished records exist, usually in the private collections and/or museums. With the publication of such data, the knowledge about the moth fauna of Croatia would be greatly increased, and the creation of the checklists of Lepidoptera of Croatia would be more plausible.

Special attention should be given to the species listed in the Annexes II and IV of the Habitats Directive (COUNCIL DIRECTIVE 92/43/EEC). In regard to moths, only two species are listed as present in Croatia, Eriogaster catax (Linnaeus, 1758) and Euplagia quadripunctaria (Poda, 1761) (11). A third species, Erannis ankeraria (Staudinger, 1861) is known to occur in the country (12), but has not been added to the list due to the lack of recent records. Here we present the first record of the fourth species, the Erebid Arytrura musculus (Menetries, 1859).

Material and Methods
A single specimen was recorded during a moth survey in Lonjsko Polje, Lipovljani municipality, Kraljeva Velika settlement, Željan stream, 17.6.2016, N: 45.386817°, E: 16.787983°, 141 m a.s.l., leg. M. Zadravec. The Natura 2000 site Lonjsko Polje (HR2000416) is located in the Sava River floodplain. Its boundaries are practically synonymous with the borders of the Lonjsko Polje Nature Park. The survey location is located within the “Josip Kozarac” Forestry Unit, in the centre of the Park. The habitat is typical for the area, consisting of floodplain oak forests (As. Alno-Quercion roboris Ht. 1938, National Habitat Classification Code: E.2.2) with Genista tinctoria (13). Two pyramidal light traps were used in the field, and two hours were spent at the locality. The collected specimen was mounted, identified, and stored in the private collection of the first author (Koren, Zagreb). The light traps were set up on a macadam road connecting the settlements Kraljeva Velika and Trebež, through the forest sections. The stream Željan flows by the road in that part, crossing from one side to the other. Two drainage canals, moving water from the forest and into the stream, are also present (Figure 1). For the identification of the collected material we used standard identification keys (14).

Figure 1. Habitat on which A. musculus was recorded in Lonjsko Polje, and the collected specimen.

Results and Discussion
This rare noctuid species is disjunctly distributed across parts of south-eastern Europe and Asia. In Europe, it is very local, with most records originating from Eastern Europe (Ukraine, Russia, Hungary, and Romania) (15, 16). It is known also from northern Serbia (17). Recently it was also discovered in Italy (18). The closest locations to the Croatian one are in Hungary, approx. 122 km and 133 km away, at Pécsi-sík and Kis-Balaton, respectively (19).

The country within Europe with most records is probably Hungary, where during the last decades the knowledge about the distribution of this species has been drastically increased (see 15). The most probable reason is that formerly insufficiently surveyed parts of Hungary are being surveyed (15). However, the data about its biology and ecology are still not sufficient and according to the Hungarian Red Book it is considered to be a critically endangered species (15).

It has one generation per year, and it flies between June and July. It is considered to be a tertiary, possibly an interglacial, relict (15). It inhabits special wetland habitats like marshes, mires and bogs – habitats that have in the past greatly diminished in their extent across all of Europe, and in some countries are still disappearing. Due to its size and colouration, it cannot be confused with any other European species.

This species is listed both in Annexes II and IV of the Habitats Directive, Annex II containing species requiring the designation of Special Areas of Conservation (SACs), while Annex IV contains species in need of strict legal protection (COUNCIL DIRECTIVE 92/43/EEC).

In total, 22 Natura 2000 sites were designated for the long term survival of this species within the European Union (Fig. 2), one in Italy, eight in Hungary and 13 in Romania (5). In Croatia, this species needs to be added to the Natura 2000 site Lonjsko Polje (HR2000416), as well as the list of Natura 2000 species for Croatia, at the earliest possible opportunity. The area of Lonjsko Polje contains a different array of wetland habitats, including riparian forests and wet meadows, river banks and embankments. This corresponds to the known habitat preferences of this species. As suggested by Baranyi et al. (15), aside from light trapping, the search for the overwintering specimens as well as larvae could be used to gain additional data about the occurrence of this species.

Figure 2. The distribution of A. musculus in central Europe with the new record from Croatia. 1 - Csohos-tó, 2 - Dealul Mocrei - Rovina - Ineu, 3 - Defileul Mureşului, 4 - Delta Dunării, 5 - Balaton, 6 - Mlaştina Satchinez, 7 - Martinkai-legelő, 8 - Lunca Mirceşti, 9 - Kék-Kálló-völgye, 10 - Dealul Mare - Hârlău, 11 - Fânaţele Bârca, 12 - Kis-Balaton, 13 - Risorgive dello Stella, 14 - Tapolcai-medence, 15 - Pădurea Hagieni - Cotul Văii, 16 - Pădurea Medeleni, 17 - Pécsi-sík, 18 - Râul Prut, 19 - Sărăturile din valea Ilenei, 20 - Sărăturile Jijia Inferioară, 21 - Turbăria de la Dersca, 22 - Turjánvidék, 23 - Lonjsko Polje.

Also, detailed surveys of the whole Lonjsko Polje area, as well as other wetland areas in northern Croatia (e.g. Žutica Forest, Kopački Rit, Aljmaški Rit) is needed in order to establish the distribution, assess the status, and assure the long term conservation of this rare species.

Acknowledgements
This moth was collected within the project „Monitoring of the stag beetle (Lucanus cervus) in Nature Park Lonjsko Polje in 2016” and we are immensely grateful to the Park officials for their support. Moth surveying was carried out with permission from the Ministry of Environmental and Nature Protection (Permit No.: 517-07-1-1-1-16-4, issued on 28 April 2016).

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