New records of some rare mayflies ( Insecta , Ephemeroptera ) from Ukraine

Palingenia fuliginosa (Georgi, 1802) and Isonychia ignota (Walker, 1853) are reliably recorded in Ukraine for the first time. New localities where larvae of Brachycercus harrisella Curtis, 1834, Siphlonurus aestivalis Eaton, 1903 and Metreletus balcanicus (Ulmer, 1920) develop in Ukraine were registered. Baetopus (Raptobaetopus) tenellus (Albarda, 1878) is given for Ukraine for the first time. Investigated microhabitats of these species are shortly described. Main factors influencing the abundance of P. fuliginosa in detected habitats are discussed. Isonychia ignota, P. fuliginosa and M. balcanicus are recommended to be included in the next edition of the Red Data Book of Ukraine.


Introduction
Mayflies (Ephemeroptera) is a very important group in the aquatic biocenosis.The majority of mayfly species is sensitive to pollution and changes of hydrological regime of waterbodies.Therefore this group is commonly used in bioindication and biomonitoring.These investigations are actual because of the ecological situation of the modern world.Bioindication and biomonitoring investigations in any region are impossible without the study of the fauna structure.Thereby, the identification of a species composition (faunistic investigation) is the initial stage of any research.
The investigation of mayflies in Ukraine began in the second part of XIX century, but up to now there were only a few decades of intensive research.Most intensive period of study has begun in 1997 and continues up to now.The first check-list of mayflies of Ukraine was published in 2003 (Godunko & Kłonowska-Olejnik 2003).

Material and Methods
All specimens were preserved in 85-95% EtOH.Administrative disposition and geographical coordinates of localities are given according to "Google Earth" (http: // earth.google.com).Photographs of mayfly specimens were taken using Canon SX30SI ( Figs 1, 2, 5 The material is housed in the collection of author at the NMNH NASU.All vials have the inventory numbers (IN) (example: Zkp10Metbal/1).
Generally confirmed distribution of P. fuliginosa falls within Iran, Caucasus and Slovak Republic (Tshernova 1949;Demoulin 1965;Soldán 1978).Demoulin (1965) recorded P. fuliginosa for Crimea basing on one female imago from Kertch Peninsula.It was supposed that species do not develop in Crimea, and the caught specimen was carried by wind from Krasnodar Krai (Russian Federation) (Prokopov & Godunko 2007).The records of this species from the Salgir and Angara Rivers at Crimea by Kiseleva & Yezernitskiy (1985) was subjected to great doubt and consequently the species was removed from check list of mayflies of Crimea (Prokopov & Godunko 2007).Thereby, up to now there are no facts confirming the development of this species within Ukraine.
We found P. fuliginosa in potamal zone of the Horyn' and Styr Rivers within Rivne Region (Figs 3,4,14,15).Larvae of different ages and winged stages were collected (Figs 1, 2, 5); this confirms the fact of development of the species within Ukraine.Moreover, these records extend the known distribution of the species towards North.
Habitat: In both rivers larvae of P. fuliginosa live under the similar conditions.All larvae were collected from their burrows in different substrates.Most typical substrates were the clay (Fig. 5) and dense deposits of sand, and we also collected some larvae from burrows made in poor bog iron ore with sandstone impurities (Fig. 6).Additionally we recorded that the larvae of last instars can rote the burrows through the wood when it is deposed in the main substrate (Fig. 7).
Current velocity in collecting sites ranged from 0.1 to 0.3 m/s.The inhabited holes of P. fuliginosa were registered at depth from 0.2 to 1.7 m (max depth of the rivers in the sampling places was about 3 m).The additional parameters of waterbodies in collecting places measured during the sampling were: water temperature 23-29°C, water hardness 259-270 ppm, pH 8.6-8.7.
Material   Threats and recommendations for conservation: Palingenia fuliginosa is a highly stenobiotic species that prefers only the oxygenated unpolluted waterbodies.As the result, species inhabits only a few rare types of microhabitats in some middle-sized rives within Ukraine.We suppose that at the present time there are several main factors influencing the abundance of the species in discovered habitats except of the moderate pollution.The first factor is the significant decrease of the average water level in Horyn' and Styr Rivers in last few years.Because of this decrease the main part of the suitable microhabitats appeared to be located above the water during most of a year.Many old burrows made by larvae of P. fuliginosa were registered above the water level.Now only a small area with suitable microhabitats was preserved in these rivers.Larvae of the species can not inhabit bottom and neighboring microhabitats because of their siltation.
The second factor is the human factor.It is very popular among the people of Rivne Region to collect the larvae and winged stages (imagoes and subimagoes) of P. fuliginosa for fishing.We consider this as a significant threat.People use special hand device that scrapes the substrate to collect the larvae (Fig. 8).Because of this the large areas of rare suitable habitats of the species were destroyed.Also people collect the newly emerged winged stages (mainly subimagoes) with the light traps.Before the water level decrease in the Horyn' and Styr Rivers some people collected for the sale up to one hundred (!) kilograms of larvae and up to 5-6 hundreds (!) kilograms of winged stages (mainly subimagoes).Obviously the caught subimagoes could not participate in the reproduction.Because of significant restriction of the species' distribution in the region, small area and number of suitable microhabitats and big volume of collected mayflies, we consider the human activity as one of the significant threats for the discovered (!) populations of P. fuliginosa.
Thus, we suppose that this species deserves to be included in the Red Data Book of Ukraine.Detailed investigation (also genetic affinity to other populations) of discovered populations of P. fuliginosa continues.

Isonychia ignota (Walker, 1853)
This species was given for Ukraine in Godunko & Kłonowska-Olejnik (2003) basing on data of Mikulski (1936).The latter article was devoted to Ephemeroptera of Poland that previously included some regions of modern Western Ukraine and Belarus.Mikulski (1936) declared I. ignota for tributaries of the Prypyat' River without precise points.Basin of this river falls within territory of modern Ukraine and Belarus.During the revision of the collections housed at the Institute of Systematics and Evolution of Animals PAS (Kraków), where the materials of J.S. Mikulski is housed, none specimen of I. ignota from the basin of Prypyat' River was found (Kłonowska-Olejnik et al. 2005; Godunko R.J. personal communication).Thus, up to know there were no confident records of I. ignota for Ukraine.
We registered I. ignota (Fig. 9) in potamal zone of meddle-sized Horyn', Styr and Sluch Rivers within Rivne Region (Figs 3,14,15).These rivers are the right tributaries of the Prypyat' River of the first or second orders.We found fresh exuvia of I. ignota at the Styr River in the first decade of August; this confirms that a part of population of I. ignota emerges at this period.
Habitat: In all rivers the larvae were registered at microhabitats with sand, sometimes with small stones or/and pieces of bog iron ore, or silted sand bottom and current velocity from 0.2 to 0.3 m/s.Larvae were collected from bottom and vascular aquatic plants, Potamogeton natans Linnaeus, 1758 and P. pectinatus Linnaeus, 1758 mainly.The additional parameters of waterbodies in collecting places measured during the sampling were: water temperature 23-30°C, water hardness 210-270 ppm, pH 8.6-9.0.
Threats and recommendations for conservation: Water pollution is the most obvious threat to I. ignota.In common with other Ephemeroptera, this species relies upon good water quality.Other concrete threats for I. ignota within Ukraine are not defined.We consider that it deserves to be included in the Red Data Book of Ukraine because of the restricted distribution within the country, its rarity within the whole areal and stenobiotic nature.Detailed investigation (also genetic affinity to other populations) of Ukrainian populations of the species continues.
) in the National Museum of Natural History of the National Academy of Sciences of Ukraine (further NMNH NASU) and Leica Z16 APO with Leica DFC450 Digital Camera (Figs 9-12) in the I.I.Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, and subsequently processed with LAS Core 3.8 and Adobe Photoshop™ CS5 software.