Records of larentiine moths (Lepidoptera: Geometridae) collected at the Station Linné in Sweden

Abstract Background The island of Öland, at the southeast of Sweden, has unique geological and environmental features. The Station Linné is a well-known Öland research station which provides facilities for effective studies and attracts researchers from all over the world. Moreover, the station remains a center for ecotourism due to extraordinary biodiversity of the area. The present paper is aimed to support popular science activities carried out on the island and to shed light on diverse geometrid moth fauna of the Station Linné. New information As an outcome of several research projects, including the Swedish Malaise Trap Project (SMTP) and the Swedish Taxonomy Initiative (STI) conducted at the Station Linné, a list of larentiine moths (Lepidoptera: Geometridae) collected on the territory of the station is presented. Images of moths from above and underside are shown. Of the totally 192 species registered for Sweden, 41 species (more than 21%) were collected in close proximity to the main building of the Station Linné. Malaise trap sampling of Lepidoptera is discussed.


Introduction
The island of Öland, at the southeast of Sweden, is famous for its dominant environmental feature, an Ordovician limestone pavement, which is called the Stora Alvaret (= the Great Alvar). Alvars are semi-natural grasslands which have been formed and developed due to long periods of human influence, including grazing (Rosén 1982). The Stora Alvaret has been designated as a World Heritage Site by UNESCO due to its unusual biodiversity and prehistory. Station Linné is situated on the island of Öland being a center for research, popular science activities, and ecotourism. The research station is named after Carl von Linné who visited Öland in 1741.
The Swedish Malaise Trap Project (SMTP), funded by the Swedish Species Information Centre (ArtDatabanken), is based at the Station Linné. The project aims to provide species determinations for the specimens obtained from Malaise traps sampling at a wide range of landscapes and habitats. For many groups, including geometrid moths, the final data release is still awaited. The present paper is aimed to present a first list of the larentiine moths collected at the Station Linné.

Materials and methods
Material for study was mainly collected using a UV light trap (UV), a mercury vapor light trap (MV) and net sweeping (NS) by O. Schmidt in 2014 (June 24-29, July 1-4) and 2015 (July 20-31) in the Mörbylånga kommun, Skogsby, Station Linné (56.6186 N,16.4989 E). The UV light trap was placed between the tree and shrub rows along a walking path, with a meadow on one side and a swampy area on the other side (Fig. 1). The mercury vapor light trap was situated nearby, at the edge of the swamp (Fig. 2)
The genitalia of all small-sized moths were studied to correctly identify the species. The material was identified using the Lepidoptera collection of the Zoologische Staatssammlung München (ZSM, Germany) and publications by Mironov (2003), Elmquist et al. (2011) andHausmann andViidalepp (2012).

Morphological differences within Gandaritis pyraliata (Denis & Schiffermüller)
A series of specimens presumably belonging to the species Gandaritis pyraliata have been collected. The specimens display variation in the wing pattern above and underneath, in the male genitalia (the shape of the saccus) and in the female genitalia (the length of the ductus bursae and the shape of the signum). The specimens require more detailed study.

Malaise trap sampling of Lepidoptera
Malaise traps are effectively used for collecting small flying insects for many decades, after the trap has been described by Malaise (1937). Although butterflies and moths are sometimes target groups of large-scale malaise trap sampling for ecological and conservation studies (e.g. Basset et al. 2007, Campbell and Hanula 2007, Lamarre et al. 2012, collecting Lepidoptera by means of malaise traps is a challenging method. Designed for Diptera and Hymenoptera, a malaise trap indeed effectively samples Lepidoptera, as they get trapped within the malaise tent, flying upward towards either the sun (during the day) or the moon (at night) (see Lamarre et al. 2012). However, the specimens fall into a collecting jar filled with Ethanol, whereby the wing scales rub off easily. Generally, only specimens with distinct wing pattern can be reliably identified from the samples in Ethanol. The older the samples are, the more difficult it is to get a correct identification of Lepidoptera. For small moths it is necessary to study the genitalia or to perform a molecular analysis. Considering the results of present study, using only malaise traps for sampling Lepidoptera is advisable for well-studied faunas. Traditional methods, like net sweeping, light trapping or bait-traps deliver more suitable results.