The fauna of Geometrid moths of the Natural Forest Reserve “Cobîleni” Republic of Moldova – Preliminary data

Cobîleni Natural Forest Reserve with a surface of 33.5 ha is situated near Lopatna village, Orhei district, on the right bank of the Dniester River. The aim of the study was to assess the geometrid moths (Lepidoptera, Geometridae) fauna from this reserve. The most part of entomological materials from Cobîleni Natural Forest Reserve discussed in this paper were collected at the light trap during vegetation period of 2018. In the paper the list of fifty-five geometrids species is given, also their geographical distribution, ecological and trophic structure. The geometridae species collected from this reserve belong to five subfamilies. Most of the captured specimens belong to the Ennominae subfamily with 36 species, as it is typical for mesophilous meadows, followed by Sterrhinae with nine species, then Larentiinae with eight, and finally Orthostixinae and Geometrinae with only one species each. In the result of establishing of taxonomic affiliation of the entomological material collected during 2018, a new geometrid species for the fauna of the Republic of Moldova was identified: Cyclophora linearia.


Introduction
It is well known, that the forests around the world are regarded as the most species rich habitats, especially for arthropods (Stork et al. 1997), that's why, protecting these ecosystems worldwide it is a primary task for all of us. Forests cover approximately 45% of Europe continent surface, being one of the most important terrestrial ecosystems (FAO 2010). Most of forested areas have management plans and just 6% of these forests are protected (FAO 2020). Regarding the National Forest Land of the Republic of Moldova, that accounts for roughly 12.7% of country territory (MoldSilva.gov.md), majority of forestland being under the state property. Despite the fact that the country has a small territory (33,843 km 2 ) a surface of 61,236.6 ha from the National Forest Land are taken under protection .
The territory of the Republic of Moldova is situated at the interference of tree biogeographical regions: Central European forests, Mediterranean forests and Eastern European steppe, with transition zone between European forests and steppe region of Asia. Due to this fact, we have various unique landscapes, natural monuments with international value, and places filled with the charm of nature. Parts of these territories with a high biodiversity for the Republic of Moldova have been taken under the State Protection, one of them being and the Cobîleni Natural Forest Reserve.
The present study provides the first report regarding the diversity of Geometridae moths (Lepidoptera) from the Cobîleni Natural Forest Reserve from the Republic of Moldova. From flora point of view, the Cobîleni Natural Forest Reserve is well studied, but regarding the fauna -this is poorly known.
Despite of small territory (33.5 ha), the Cobîleni Natural Forest Reserve includes landscapes of flooded meadows, mixed forests and limestone rocks. The rock forest, specific to the steep slopes of the Dniester valley, are dominated by Quercus robur and Fraxinus excelsior species.
The objectives of the present paper were to investigate and to reveal the species of the Geometridae group from this reserve, their ecology and biology, not only for the tree pests but for the rare and banal, too.
We chose this theme due to that fact that Geometridae group is poorly studied not only from this reserve, but in our country, too. The last papers regarding this insect group were intended for the study of two major entomological collections: the "Catalogue of the N. Zubowsky" (Derjanschi et al. 2016) and Ruscinski (Timuș et al. 2017) whose entomological materials were collected in the early 1900s. Also, some short information about the distribution area, host plants, and ecological preference are given in this paper. Another purpose of this study was to research the forest pests from this part of country. It is well known that we have several species from Geometridae that form an ecological group belong to the most important forest defoliators, herbs and shrubs that cause serious damages in the forests, orchards, parks, etc. of the Republic of Moldova (Bulgari et al. 2016;Derjanschi et al. 2012;Rodideal et al. 2015;Wahlberg et al. 2010).

Materials and methods
The study area. The study was conducted in the Cobîleni Natural Forest Reserve (47°30'50.94"N, 29°1'20.37"E) of the Republic of Moldova ( fig. 1), which is taken under protection since 1998. The reserve belongs to the Forest District Susleni, of State Forestry Enterprise Orhei (which occupies an area of 23,822 ha) (Postolache and Lazu 2018). The Cobîleni Natural Forest Reserve is a natural forest area with a surface of 33.5 ha, situated near Lopatna village, Orhei district, on the bank of the Dniester River ( fig. 2).
According to the geomorphological regionalization, the reserve is located on the west Dniester's hills and its terraces, at 250-300 m altitude, characterized by a vertical fragmentation. Flooded meadows, mixed forests and limestone rocks, specific to the steep slopes of the Dniester Valley, covered by Quercus robur and Fraxinus excelsior, represent the studied reserve ( fig. 4).
The vegetation of steep section in the middle part of the reserve, exposed to the east, consist of Stipa pulcherrima, Amygdalus nana, Rhamnus cathartica, Thalictrum minus, Silene fabaria etc.      different methods: by sweeping with sweep net and during night with UV-light bucket trap with DRL 250W lamp bulbs. The biggest part of moths was caught using UV-light trap. The UV-light trap is composed from three panels surround the luminescent lamp of the trap. As a result of attracting insects by the UV-light, these are hitting on the panels, and after this, they fall in a funnel put under the lamp ( fig. 5). The funnel is mounted on a glass jar with gasoline for to immobilize the insects and to kill the specimens after they land on the surface of light trap (Yi et al. 2012). Collecting of diurnal species was done with entomological net.
Sorting and preservation of samples. The collected entomological material in killing jar and paper triangles were taken to the laboratory of the Entomology Department of the Institute of Zoology of the Republic of Moldova for further sorting by groups. Paper triangles containing geometrids moths are stored in 21.59 cm x 27.94 cm zip lock plastic bag in the freezer. Arthropods other than Geometridae were emptied in jar with 70% ethanol or paper triangles and appropriate labels (dates and location). The adults' genitalia structure was studied to confirm the taxonomic affiliation. For slide preparation of male and female genitalia, each specimen' abdomen was macerated in 10% NaOH during 24 hours at room temperature. The species identification was done using a microscope MBS-10.

Results
The environmental conditions of the Cobîleni Natural Forest Reserve such as humidity, temperature, altitude and vegetation determined a variation in the species diversity of Lepidoptera insects, including geometrid moths. As a result of investigations made during of the vegetation period of 2018, in this reserve, 370 specimens of Geometridae were collected The collected geometrid specimens belong to 55 species, taxonomically classified in 48 genera and 5 subfamilies (tab. 1). The systematic of collected species in this paper is done after Hausmann and Sihvonen (2019). According to the data form the table 1, the subfamily with greatest species richness from this reserve proved to be Ennominae with 36 species (65.5 %), followed by Sterrhinae with nine species (16.4 %) and Larentiinae with eight (14.5 %). The last two subfamilies -Orthostixinae and Geometrinae with only one species each (1.8 % each). Such a big species number in Ennominae subfamily is due to the fact that this subfamily is the largest of the Geometridae family, with more than 9,700 described species of 1,100 genera all over the world, and in Europe -202 species (Müller et al. 2019).
Out of 48 genera, the most diverse genera were Cyclophora with four species, Agriopis -3, Abraxas, Ennomos and Lomographa with two species each.
A majority of Geometridae species (35) collected in the Cobîleni Natural Forest Reserve have an Euro-Asian distribution that consist -63.6 %. Also, we have 12 Palaearctic species which comprise 21.8 %, and three species are Ponto-Mediterranean (5.45 %). Finally, Ennomos quercinaria is an Euro-West Asian element, C. porata is an European element, L. purpuraria has West Asian-Mediterranean distribution, but A. leucophaearia and A. marginaria are West Palaearctic species (fig. 6).
From 55 collected species in the Cobîleni Natural Forest Reserve, 37 are mesophilous elements (67.2 %) and 4 species (7.3 %) are meso-hygrophilous inhabiting mesophilous grasslands, gardens, scrubland and mixed forests, forest fringe, brushwood of shrubs, river plains. Other seven species (12.7 %) are mesothermophilous elements, four meso-xero-thermophilous species (7.3%) and three xero-thermophilous (5.5 %). The xero-thermophilous geometrid species inhabit dry,  and open grassland, in this reserve, characteristic of steppes or are found both on dry southern slopes, and on more damp meadow-vegetation, but mainly in open, sunny places (figs 3, 7). Regarding the larvae trophic spectrum of these identified 55 geometrid species from the Cobîleni" Natural Forest Reserve, 58% are forest tree defoliators. From 29 tree defoliator species collected in the reserve, 20 species, which consist approximatively 36.4% from all collected species, feed mainly on deciduous trees. The geometrid caterpillars of nine species (16.4 %) are shrubs and trees defoliators: L. bimaculata, A. grossulariata, L. temerata, Ph. pilosaria, E. defoliaria, A. aurantiaria, C. pusaria, H. flammeolaria and O. brumata (tab . 1, fig. 8). In addition, during the study in the Cobîleni Natural Forest Reserve, butterfly specimens of five species which larvae are just shrubs consumer were collected. Thus, the inchworms of A. prunaria feed on Betula, Alnus, Salix, Ribes, Vaccinium etc., of A. syringaria on Syringa and Lonicera;   In the sub parcels where the predominant species is the Scots pine (Pinus sylvestris), we collected adults of H. fasciaria whose inchworms are coniferous consumer.
The plant hosts of the larvae of twenty species (37%) are flowering plants and spontaneous herbs, collected in the reserve or from the adjacent biotypes. The caterpillars of O. bidentata and A. repandata feed on deciduous trees, shrubs and spontaneous herbs (tab. 1).
In addition to common species undoubtedly, the most important insect species from the whole territory of the reserve are those ones having the statue as new for the fauna of the Republic of Moldova or / and are considered threatened in neighbour countries and Europe. After studying the literature regarding the geometrid diversity of the Republic of Moldova (Hormuzaki 1894; Zubowski 1908-1913;Zubowsky and Ruscinski 1938;Miller et al. 1930;Miller et al. 1932;Apostolov 1970;Derjanschi et al. 2016;Timuș et al. 2017) the Clay Triple-lines -C. linearia is a new species record for Republic of Moldova.

Discussions
With the 55 Geoemetridae moth species recorded during this research, which represents more than 20% of the country's Geometridae fauna, the area of the Cobîleni Natural Forest Reserve represent a particular importance in terms of biodiversity.
From the collected species, several are dangerous forest and agriculture pests. Therefore, L. purpuraria and I. arenacearia are pest of alfalfa (Nestorova 1998) (Patočka et al., 1999, Bulgari et al., 2016, Derjanschi et al., 2012, Rodideal et al., 2015. In outbreaks with high numerical density, the inchworms can produce partial or total tree defoliations, especially on Quercus sp., also on Tilia sp., Carpinus sp., Corylus sp., Cornus sp. and Prunus sp. The adults of most important Geometridae pests occur in the cold part of the year (late autumn or early spring) and their brachypterous females are unable to fly (Wahlberg et al. 2010).
Regarding the new species for the fauna of the Republic of Moldova -the C. linearia has a Palaearctic distribution area, being a common species in Europe in the beech forests (primary host-plant), deciduous and mixed forests, parks, scrub (where bilberry, oak and willow are second host-plats) and of course in the gardens. In conditions of Europe, the Clay Triple-lines hibernates as pupae under the fallen leaves, having two generations per year. The first generation can be seen from third decade of April to June and the second one from July to September. Triple-lines develops in June-July and August until early autumn being easily observed on low branches of host plants.
If we take into consideration the conservation status, we should mention that the rarity status of geometrids on the territory of the Republic of Moldova is not established, due to the incomplete study of this butterfly group. We should mentioned that Swallow-tailed Moth, O. sambucaria, one of largest and striking Geometrids in the Republic of Moldova, in Romania, it is a Critically Endangered species. Species A. sylvata (Scopoli, 1763), O. cribraria (Hübner, [1799]) and S. tessellaria (Boisduval, 1840) are vulnerable (Rákosy et al. 2003) and more than twenty are Near Threatened in Romania and other countries of Europe (Rákosy et al. 2003;Inokaitis and Paulavičiūtė 2020 etc.).