Contribution to the Biology of Hippeutis Complanatus (Linnaeus, 1758) (Gastropoda: Planorbidae): Life Cycle in Silesian Woodland Ponds (Southern Poland)
Total Page：16
File Type：pdf, Size：1020Kb
Vol. 20(4): 279–287 doi: 10.2478/v10125-012-0023-1 CONTRIBUTION TO THE BIOLOGY OF HIPPEUTIS COMPLANATUS (LINNAEUS, 1758) (GASTROPODA: PLANORBIDAE): LIFE CYCLE IN SILESIAN WOODLAND PONDS (SOUTHERN POLAND) ANETA SPYRA Department of Hydrobiology, Faculty of Biology and Environmental Protection, University of Silesia, Bankowa 9, 40-007 Katowice, Poland (e-mail: [email protected]) ABSTRACT: In spite of the common occurrence of Hippeutis complanatus (L.) in some regions of Poland, it is considered to be a rare species with scattered sites. A study on its life cycle and shell growth in various condi- tions was possible due to the existence of very abundant populations in several woodland ponds of Silesia. The snails breed twice in a lifetime, and two generations reproduce in one year. The main breeding period is July/August. Some individuals breed also in the spring of the next year. The first appearance of the smallest in- dividuals is clearly related to the water temperature. KEY WORDS: Hippeutis complanatus, reproductive biology, life history, freshwater snails, Planorbidae INTRODUCTION Hippeutis complanatus (Linnaeus, 1758) is a but for example in Germany (Hamburg) it could be Palaearctic species, mostly inhabiting small, well-vege- found in 29% of 14,000 sampling sites (GLÖER & tated water bodies with a muddy bottom (PIECHOCKI DIERCKING 2009) and is not regarded as endangered. 1979, ØKLAND 1990, KERNEY 1999). It lives in lakes of Previous studies (SPYRA 2010) showed that in Polish different size and trophic level, including dystrophic woodland ponds the species may form abundant pop- environments (AHO 1966) as well as bogs (BÁBA ulations (up to 11,136 of collected specimens). 1991). It is found in water bodies surrounded by fields Most planorbids have a one-year life cycle and re- and deciduous forests (ØKLAND 1990). An extensive produce only once. Their reproduction starts in survey in Hamburg showed that the species preferred spring and juveniles hatch in early summer (PIECHOC- well-vegetated ditches (45% of 399 sampling sites) KI 1979). The parental generation dies having laid (GLÖER &DIERCKING 2009). Its shell is lenticular, eggs in July and August (e.g. Anisus leucostoma (Millet, very flat, finely ribbed and shows a small shape varia- 1813), A. vortex (Linnaeus, 1758), Bathyomphalus tion (PIECHOCKI 1979). contortus (Linnaeus, 1758), Gyraulus crista (Linnaeus, Some authors (MERKEL 1894, ZEISSLER 1987, 1758) and G. albus (O. F. Müller 1774)). There are no STRZELEC 1993) regard H. complanatus as a rare spe- literature data on the biology of H. complanatus (L.), cies which occurs in scattered sites, mainly because of including its life cycle, reproduction, breeding season the degradation of the freshwater environments as a or size structure. Some information can be found in result of drainage of wetlands and riverside meadows, NEKRASSOW (1928) and BONDENSEN (1950). The aim eutrophication and pollution. In the Polish Red List it of this study was to ascertain the course of its life cycle, is regarded as a species with an established but un- the breeding period and the size structure dynamics specified risk, deserving the endangered status due to during the year. The existence of very dense popula- the decline of wetland environments (PIECHOCKI tions in several anthropogenic woodland ponds in 2002). In Poland it usually occurs in small numbers Silesia made such investigations possible. 280 Aneta Spyra MATERIAL AND METHODS STUDY SITES ing fish catches (Figs 2–5). Allochthonous leaf depos- its formin the riparian zone of the ponds (Fig. 2). The investigations were carried out fromJune 2009 The ponds are 11.4 to 67 ha (Table 1) in area, and to May 2010 in five woodland ponds in a forested area the water level varies between months, especially in of Upper Silesia (Silesian Upland, Southern Poland) summer. The ponds are shallow, with maximum (Fig. 1). The ponds are stocked with Carassius auratus depth of 3.5 m. Being subsidence ponds resulting (L.), C. auratus gibelio (Bloch), Cyprinus carpio (L.), fromcoal mining,they are supplied with water from Tinca tinca (L.), Anguilla anguilla (L.), Esox lucius (L.) different sources: surface run-off, woodland ditches and Perca fluviatilis (L.); ponds 3 and 4 are emptied dur- (ponds 3 and 4) and rain waters, contrary to typical Table 1. Characteristics of the investigated woodland ponds Pond 12345 Kind of pond subsidence pond subsidence pond fish pond fish pond storage reservoir Surface area in ha 22.3 6.7 23 6.17 11.4 Maximal depth in m 3 3 1.8 1.9 3.5 Bottom sediment sand-mud sand-mud mud mud sand-mud Persistence permanent permanent artificially artificially permanent drained* drained* Calciumcontent (mg/L) 20–31 14–34 19–30 29–33 13–22 Total hardness (dH) 7–7.2 3–7.3 4.2–7 4.3–7 2.1–5.8 Temperature (°C) 4–30 4–26 6.4–21 6.3–21.2 6.1–23.4 * water level regulated artificially every few years Fig. 1. Location of the study area Life cycle of Hippeutis complanatus 281 Figs 2–5. Woodland ponds in the study area: 2 – leaf deposits in pond 1, 3 – site of Hippeutis complanatus in pond 3; 4 – wood- land pond 4, artificially drained in November 2009; 5 – sampling site in pond 5 fish ponds. In winter they freeze over partially or com- cording to HERMANOWICZ et al. (1999). The water pletely to the bottom. temperature was measured in the field using Hanna Instruments portable meters. SAMPLING AND DATA COLLECTION Cocoons were collected fromleaf deposits and re - mains of water plants during sample sorting. They In each pond monthly samples of freshwater snails were visible on the underside of the leaves and plant were taken using a frame (50×50 cm – sample area remains. In addition, specimens of H. complanatus 0.25 m2). The material was collected from leaf debris were collected, which were then used in the labora- and remains of water plants. The material was trans- tory breeding experiments. The cocoons laid on the ported to the laboratory where the samples were aquariumwalls and on the submergedleaves were sieved through a 0.23 mm mesh sieve, which ensured compared with those found in the field samples; this that newly hatched H. complanatus were retained. The confirmed the identity of the field-collected eggs. snails were sorted under a stereomicroscope, and the specimens of H. complanatus were separated from BIOMETRICAL DATA AND STATISTICAL other snails. The snails were preserved in 75% etha- ANALYSIS nol and identified using GLÖER (2002). The density of individuals per 1 m2 was estimated. The shell height and width were measured and the Immediately prior to the sampling, water samples whorls were counted. In total 4,013 individuals of H. were taken in each site. Some physical and chemical complanatus were collected and measured, which al- parameters of the water, affecting the occurrence of lowed a detailed characterisation of the shell size vari- the snails (e.g. temperature, total hardness, calcium ation in the studied ponds. Five size classes (shell di- content), were analysed with standard methods, ac- ameter) were distinguished: class 1 – £1 mm, class 2 – 282 Aneta Spyra 1.1–2 mm, class 3 – 2.1–3 mm, class 4 – 3.1–4 mm, and Spearman Rank Correlation Coefficient r2. Non-para- class 5 – ³4.1 mm. Individuals larger than 5 mm were metric Kruskal-Wallis one-way ANOVA and multiple very rare. comparisons tests (post-hoc) were used to determine The results were statistically analysed using Statisti- the significance of the differences between the shell ca for Windows (Version 9.0). Correlation between size among different months. Only the differences at the water temperature and the abundance of the p<0.05 were regarded as statistically significant. smallest specimens was determined using the RESULTS POPULATION STRUCTURE five snail species in pond 2 and 12 species in pond 5 (Table 2). The density of H. complanatus was high, and Though the samples were collected during 12 varied among the ponds and months of research. The months, H. complanatus was present only in the highest densities were observed in ponds 1 and 4 in samples from April to November. It co-occurred with September (1,124 ind./m2 and 1,936 ind./m2, respec- tively), and in pond 5 (2,324 ind./m2) in October Table 2. Gastropod species co-occurring with Hippeutis com- (Table 3). planatus in the investigated woodland ponds The biggest shells of H. complanatus were 5.40 mm Pond wide (Table 4) and had 4 whorls. The shells of newly 12345 hatched individuals were 0.33 mm wide and 0.11 mm high, and had 1.5 whorls. The shell surface was spi- Lymnaea stagnalis +++ Stagnicola corvus + Radix balthica +++++ Table 3. Density of Hippeutis complanatus in the investigated 2 Galba truncatula + woodland ponds (ind./m ) Planorbarius corneus +++++ Pond Months Planorbis planorbis +++ 12345 Bathyomphalus contortus + +++ April 8 4 24 440 48 Gyraulus albus +++++ May 16 12 120 72 1,068 Gyraulus crista + +++ June 124 224 72 80 680 Anisus spirorbis + July 548 92 52 24 948 Anisus vortex ++ August 380 64 152 228 1,860 Segmentina nitida +++ September 1,124 32 276 1,936 1,644 Ferrissia wautieri +++++ October 332 44 136 300 2,324 Physa fontinalis + November 212 24 36 208 124 Table 4. Variation in shell diameter (width in mm) of Hippeutis complanatus in woodland ponds during the study period Month 30 V 29 VI 30 VII 16 VIII 23 IX 22 X 19 XI 22 IV Pond 1 min-max 2.71–4.22 0.80–3.71 0.56–3.25 0.44–2.61 0.72–2.99 0.92–2.64 0.66–2.35 3.19–3.41 N 4 31 135 95 279 83 52 4 Pond 2 min-max 3.19–4.30 0.55–3.26 0.77–3.43 0.99–2.49 1.23–2.49 1.58–2.32 1.23–2.33 3.19–4.30 N 3 51 23 16 8 11 6 6 Pond 3 min-max 1.51–4.80 0.77–4.31 1.43–2.20 0.70–3.08 0.76–2.64 1.59–3.41 1.98–2.47 3.00–3.40 N 3018133869349 6 Pond 4 min-max 1.14–3.98 0.74–4.60 0.77–4.46 0.70–3.52 0.88–2.75 1.18–3.08 1.60–2.68 3.00–3.70 N 18 20 6 57 484 75 52 110 Pond 5 min-max 0.55–5.40 0.63–5.06 0.37–4.86 0.33–4.26 0.88–3.05 0.77–3.38 1.16–2.20 3.01–3.75 N 262 170 238 462 411 581 31 12 N – number of specimens Life cycle of Hippeutis complanatus 283 Fig.