ABSTRACT
Leeches are important and reliable indicators of water quality and biodiversity in the ecosystem, so the presence of specific leech species is often closely related to basic water conditions and the presence of certain animals. This study was carried out in 2017 and 2018 in order to determine the Hirudinea fauna of some wetlands in Bingöl province. The investigation was conducted on a total of 13 stations.
The water parameters of the stations were measured and recorded in situ. The collected specimens were brought alive to the Zoology Laboratory of Bingöl University Biology Department and kept alive under room temperature conditions. The diagnosis of leech samples was made through the living samples, and they were identified at the level of family, genus, and species.
During the study, seven species, belonging to six genera and in four families were recorded. These are; Hirudo verbana Carena, 1820, Glossiphonia complanata (L. 1758), Theromyzon tessulatum (O. F. Müller, 1774), Placopdella costata (Fr. Müller, 1846), Erpobdella octoculata (L., 1758), Erpobdella testacea (Savigny, 1820), Piscicola geometra (L., 1761).
The locations where the study was carried out are new records for the detected leech species.
Keywords: Hirudinea, annelida, fauna, wetland, Bingöl
INTRODUCTION
Leeches are important indicators for water quality and biodiversity in the ecosystem and are closely related to basic water conditions and the presence of certain animals (1). These creatures are usually annular worms known as ectoparasites that feed on blood sucking. Parasitic leeches can greatly affect the fitness of their hosts depending on environmental conditions and frequency (2). More than 650 leech species have been identified by now and 15 of them are reported to be used for medicinal purposes (3). Most leeches live in burrows dug into mud at the bottom of fresh water during the hot and dry days of summer. It has been reported that organic pollutants do not harm the leeches, but the increase in acid values of the waters causes a decrease in the leech fauna (4).
Parasitic leeches have economic importance as they are used in the treatment of some diseases. It is known that leeches collected for medical purposes have been exported and become commercial products. For these reasons, H. medicinalis was classified as Endangered in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) according to the International Union for Conservation of Nature (IUCN) an international convention and it was taken under protection.
Wells and Coombes (5) reported that little is known about medicinal leeches in European and eastern Mediterranean countries. Kasparek (6) emphasized that although the country of origin of medicinal leeches is defined as Turkiye, almost no information is available. Over twenty-five years after Kasparek (6), many studies have been carried out and many new records have been identified, including two new species.
Species recorded for Turkish leech fauna are; Actinobdella sp., Alboglossiphonia heteroclite, Batracobdella euxina, Cystobranchus respirans, Dina lineata, Dina lineata lineata, Dina lineata concolor, Dina stschegolewi, Dina vignai, Erpobdella octoculata, Erpobdella vilnensis, Erpobdella testacea, Glossiphonia complanata, Haemopis sanguisuga, Haementaria costata, Helobdella stagnalis, Hemiclepsis marginata, Hirudo medicinalis, Hirudo sulukii, Hirudo verbana, Limnatis nilotica, Limnatis paluda, Piscicola geometra, Placobdella costata, Nephelopsis obscura, Trachellobdella torquate, Theromyzon tessulatum and Trocheta sp.. Among these species, the species known as medicinal leeches and used for this purpose are H. medicinalis, H. verbana and H. sulukii.
Considering these studies in the Turkish leech literature, the absence of any study on the leech fauna of Bingöl necessitated a study in Bingöl, which has an important place in the Eastern Anatolia region with its wetlands.
METHODS
Study Area
The study was carried out in 2017 (June, July, August, September) and 2018 (April, May, June, July, August, September) to determine the Hirudinea fauna of some wetlands in Bingöl province and was carried out in a total of 13 stations (Figure 1). The water parameters of the stations were measured and recorded on-site using AZ 8361 conductivity meters and AZ 8685 pH meters, and the coordinates of the stations were determined by GPS. The sampling stations and various data of these stations are presented in the table below (Table 1).
Collection and Preservation of Leeches
The samples were collected from the stations in monthly periods. The leech samples were classified according to family, genus and species categories, the collected samples were kept alive in plastic bottles, and their diagnosis was made on these live samples. The metric and meristic measurements of the morphological features of the leech samples were recorded. In order to determine the biological diversity of the leech fauna of Bingöl province, 4 samples from different species belonging to each station were stored in 70% alcohol. No leeches were killed except for 4 samples from each station in the sample stock operations. Ethics committee approval was obtained from Bingöl University Local Ethics Committee for this study (with the meeting numbered 2017/06, dated 09/06/2017, and decision numbered 06/04).
Diagnosing of Leeches
Identification of the samples was made under the Olympus SZ51 stereo binocular microscope in the Bingöl University Research Laboratory, using Sawyer (7), Elliott and Mann (8), Sládeček and Košel (9), Davies (10), Neubert and Nesemann (11) and Sağlam (12).
Statistical Analysis
IBM SPSS 25 statistical software was used to determine the relationship of leech diversity and populations with Altitude, Water Temperature, pH and Electrical Conductivity.
RESULTS
During the study, a total of 525 samples were collected from the study area and as a result of the identification of the samples, 7 species belonging to 6 genera in 4 families were recorded. Identified species are Hirudo verbana (Carena, 1820) from Hirudinidae, Glossiphonia complanata (L. 1758), Theromyzon tessulatum (Müller, 1774), Placobdella costata (Müller, 1846) from Glossiphonidae, Erpobdella octoculata (L. 1758), Erpobdella testacea (Savigny, 1822) from Erpobdellidae, and Piscicola geometra (L., 1761) from the family Piscicolidae (Table 2).
The most common species was H. verbana collected from 10 locations and then E. octoculata from 7 stations. E. testacea and P. costata collected from 4 stations, T. tessulatum from 3 stations, G. complanata from 2 stations, P. geometra from 1 station, respectively. In addition, seven of the eight recorded leech species were found in Çobantaşı (S3) and Arıcılar Hamlet 1 (S5) stations, because these ponds never dried up and so these stations were visited regularly.
In the summer of 2018, one of the two small ponds in Alatepe Village was filled with soil by the landowner, and no sampling could be made from here after July, and this leech habitat was also completely destroyed. In Karaçubuk Pond, it has been observed that the leech fauna can survive with the small amount of water remaining in the deepest area of the lake towards the end of August every year.
Spearman’s rho correlation analysis was performed to test the direction and strength of the relationship between water quality values and the detected species. According to this, it was observed that there was a positive and strong correlation between pH values and biological diversity (r=0.758, p<0.05), a positive and strong correlation between water temperature and the total number of leeches (r=0.673, p<0.05). In other words, it has been observed that as the pH value increases, the biological diversity increases, and as the water temperature increases, the amount of leech collected increases.
Furthermore, it was found to be a positive and strong relationship between H. verbana (r=0.721, p<0.05), E. octoculata (r=0.857, p<0.05), biodiversity (r=0.879, p<0.01) and total leech count. In other words, as H. verbana, E. octoculata and biodiversity in the station increase, the total number of leeches increases as expected (Table 2).
DISCUSSION
There are many studies on Turkish freshwater leeches and the studies with similar results with the species obtained in our study are listed in the table below (Table 3).
Until recently, H. verbana was known as a variation of H. medicinalis belonging to the same genus Hirudo, which had different colors and patterns. These two Hirudo species have been confused with each other for years, but in recent years, detailed studies have shown that H. verbana is not different variation of H. medicinalis on the contrary it is a completely different species (31,41,42).
It is seen that H. verbana can adapt to different water sources and has a wide ecological tolerance (11,44). It is reported that H. verbana can live on land as well as in water if there is sufficient moisture to don’t dry out (41). The incidence of H. verbana in 10 of the 13 study areas is consistent with the data on its prevalence and density.
The distribution of T. tessellatum in the world is not clear, but it is reported as the Holoarctic region. It has been reported that T. tessulatum is found in stagnant wet areas on the migration routes of birds, especially attaches to wild ducks and geese, and it sucks blood from the cheek and nasal mucous membranes of these birds (8,11). In this way, it is reported that T. tessulatum is transported between water sources by means of water birds (7,8). Due to the lack of studies on the ecological characteristics of T. tessulatum, it is thought that some physico-chemical parameters measured in the field will partially help to overcome this deficiency.
Erpobdellid leeches are known as macrophagotic predators of aquatic invertebrates. E. octoculata is one of the most common leech species in fresh waters, and it is known as stone leech, which usually lives under stones in slow-flowing lotic habitats (8).
Most of the parasitic annelid species are associated with freshwater fish (53%). The remainder is associated with marine fish (39%), brackish water fish (4%) and aquarium fish (4%) (27). P. geometra is a member of the Piscicolidae and lives as an ectoparasite on freshwater fish. While it feeds by sucking the blood of its host, it is mostly seen in and around the gills where the skin is thin, at the bottom of the fins and around the mouth. It can be found solitarily under stones in the water floor and freely on aquatic macrophytes (46).
Almost all of the leech species need similar ecological conditions. Leeches living as ectoparasites prefer places where aquatic plants are abundant in the environment so that they can approach the host where they can feed unbeknownst. Places where aquatic plants are dense allow leeches to both hide and easily reach their hosts. Considering the physical conditions of the stations in the study, the summer pH average of Çobantaşı (S3) and Arıcılar Hamlet-1 (S5) locations, which have the highest number of species, was measured as 9.6±3.1 for Çobantaşı and 9.0±3.2 for Arıcılar Hamlet-1. Especially in Çobantaşı wetland, the continuous feeding of the pond with a source ensures that the water quality remains constant, and as it can be understood from these values, the water quality of the study area shows usable characteristics. It has been observed that the small pond in “Arıcılar Hamlet-1” is fed from the bottom, even a little. Because of both stations are fed from the source shows that the water is good in terms of both temperature and oxygen. The fact that almost all the leech species recorded in the study were found in these two stations proves that leech biodiversity is related to water quality.
While the water level was sufficient in the spring in all the locations where the sampling was taken, the wetland areas became muddy after the middle of summer, especially at Karaçubuk and Alatepe stations between May and July. It has been observed that these ponds increase with the snow waters coming from the mountains in the spring, but later on, the branches flowing into these lakes dry up. The preference of these ponds for agricultural irrigation, their use for water needs of animals, and excessive evaporation cause the water in the wetland to decrease earlier or partially dry out.
Most leech species appear most abundant at pH 7.0 because pH values in the 6.0-7.0 range likely have abundant prey. It will therefore have an indirect effect on the formation and abundance of leeches. Some species have been found at pH values as low as 4.0. In a study conducted at University of Port Harcourt, Abuja (Nigeria), H. costata, H. sanguisuaga, H. medicinalis and E. octoculata species were reported in fresh water with pH 4.40-4.58 (47). Like our study, it has been reported that Hirudo and Erpobdella species can survive even at very low pH levels.
Although leeches cannot be considered as the only parameter in water quality studies due to their wide ecological tolerance, it is seen that Hirudinea members are used in water quality evaluations (48). Thanks to these data, it can be said that the water resources in the locations where H. verbana was recorded are usable in terms of water quality parameters.
CONCLUSION
It was aimed to detect leech species in a total of 13 locations within the borders of the province of Bingöl, which is located in the Eastern Anatolia Region. The detected leech species are the first record for the given locations.
ACKNOWLEDGEMENT
This study was supported by the project numbered BAP-FEF.2017.00.014, Bingöl University Scientific Research Projects Coordination Unit.
*Ethics
Ethics Committee Approval: Ethics committee approval was obtained from Bingöl University Local Ethics Committee for this study (with the meeting numbered 2017/06, dated 09/06/2017, and decision numbered 06/04).
Informed Consent: This was not required.
Peer-review: Externally peer-reviewed.
*Authorship Contributions
Surgical and Medical Practices: T.E., M.K., Concept: N.K., N.S., Design: N.K., N.S., Data Collection or Processing: T.E., M.K., N.K., N.S., Analysis or Interpretation: T.E., M.K., N.K., N.S., Literature Search: T.E., N.K., Writing: T.E., M.K., N.K., N.S.
Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: It was supported by the Scientific Research Projects Coordination Unit of Bingöl University with the project numbered BAP-FEF.2017.00.014.
