Detection of food in immature and adult stages of water scavenger beetle, Hydrophilus acuminatus (Coleoptera: Hydrophilidae)

The water scavenger beetle, Hydrophilus acuminatus (Motschulsky) (Coleoptera: Hydrophilidae), has two types of feeding modes: carnivorous during the larval stage and omnivorous during the adult stage. To investigate how the beetles detect food, larvae were provided with pond snails and snail visceral mass and adults were provided with algae and thawed blood worms. Larvae found snails and visceral mass hidden in the filter paper (only “smell” could be used); however, visceral mass was found 22–27 minutes sooner than snails, 40–53 minutes. Time to find the visceral mass that was exposed (all senses could be used) or hidden (only “smell” could be used) showed similar values, 5.4–8.0 or 7.6–8.5 minutes, respectively. Adults found algae exposed on the filter paper in 54 ± 73 minutes (mean ± standard deviation), whereas no adults found the algae hidden in the filter paper. In contrast, all adults found the thawed blood worms in the exposed (10.3 ± 13 minutes) and hidden conditions (11.0 ± 12.7 minutes). Adults did not show feeding behaviour towards the algae or thawed blood worms in the transparent microtube (only “sight” could be used). These suggest that larvae use smell, whereas adults use smell and touch and/or taste to detect their food.

SYMPTOMS OF POISONING LYMNAEA (MOLLUSCA, GASTROPODA, LYMNAEIDAE) WITH WATER MEDIUM CHROME SULFATE

Problem. Cr (III) ions are dangerously toxic for the hydrobionts of water system of the Dnieper River basin. The ions have not been previously studied in relation to their effect on a number of pond snail species. Aim. Hence, the aim of this work is to determine the range of concentrations of Cr (III) in aquatic environment that cause each of the subsequent phases of pathological process in pond snails: poisoning by the aforementioned toxicant, and presence of the complexes of symptoms of the pathological or adaptive nature that are typical for each phase. Methods.The study was conducted in 2018 in the laboratory of zoology of invertebrates of Zhytomyr Ivan Franko State University on 344 individuals of pond snails of the species Lymnaea atra, L. callomphala and L. turricula. The toxicological experiment was performed according to the technique of V. A. Alekseyev, the rate of heartbeat by D. A. Vyskushenko, the rate of branchial respiration by V. I. Zhadin, the mean daily food intake by A. P. Sushkina, the trematode (Trematoda) infection rates and morphological examination by T. A. Ginetsinskaya. Main results. Cr (III) ions are water-soluble endogenic, highly poisonous toxicant, which locally affects the respiratory branchial epithelium and skin epithelium of pond snails. The depression, and later the termination of aerobic respiration lead to their death from asphyxia. The course of poisoning is five-phase. At 0.5 MPC Cr (III) all vital functions of pond snails are carried out at the normal level (indifference phase). At concentrations of 1-2 MPC, Cr (III) ions cause an increase in their heart rate, intensity of branchial respiration, nutrition and digestion, locomotion (muscle) activity (stimulation phase). At 3 MPC of Cr (III) ions, the depression phase of intoxication develops, with the complex of symptoms including bradycardia, a sharp weakening of respiratory and trophic functions and muscle activity, with increasing degrees of hydremia, pastosity, necrosis of the respiratory epithelium and underlying tissues, and the occurrence of bleeding and hemorrhage (depressive, sublethal and lethal phases). Conclusions. The studied species of pond snails are highly sensitive to the action of Cr (III) ions and can be suggested for use as test objects in the system of hydroecological monitoring of terrestrial waters of Ukraine.

EFFECT OF Cr (III) IONS CONCENTRATION ON WAY OF LIFE SPECIFICS, TROPHIC AND DIGESTIVE PARAMETERS OF CERTAIN LIFE FORMS OF POND SNAILS (МOLLUSCA, GASTROPODA, LYMNAEIDAE)

For the first time, the influence ofCr (III) ionsin maximum concentration limits (MCL) from 0.5 –3 on the way of life, nutrition and digestion of Lymnaea vulnerata (Küster, 1862) and L. monnardi (Hartmann, 1844), –the different life forms of pondsnailsof the hydrographicnetwork of Ukraine,–was explored. Due to the long-term natural selectionamongthese specieswhich took place in extremely different ecological environmental conditions, the adaptive radiation of the shell of the ancient original form of pondsnailwas carried out by rheophilicL. monnardi and stagnophilicL. vulnerata,in opposite directions -divergently.The ampla-shaped shell of L. monnardi (flattened, low, compact, streamlined, with a large mouth) and a large flat sole prevent its driftingby thewater current, while the stagnicola-liketurret-shapeshell of L. vulnerata (elongated, high, narrow, with curls and flat turns, andsmall mouth)reliably protects it from excessive water consumption in the process of pulmonary respiration, thatis important for this ordinary inhabitant of mostly drying out ponds, experiencing conditions of desiccation, which hidesin the cracks of drying out bottom.The autochthonous fodder diet of these pondsnailsis represented by algae and higher aquatic vegetation (different in species composition for each of the species of mollusks studied).Under the maximum concentration limits of 0.5, MCL, 2MCL, 3MCLof Cr(III) ions in the environment, a 5-phase process of poisoningis being developed among the pond snails(0.5MCL-indifference; MCLand 2MCL-stimulation; 3MCL-depressive, sublethal, lethal phases). Its symptoms are clearly illustrated by the values ofthe main trophological parameters in poisoned individuals, depending on the course of the relevant phases of the pathological process.Key words : Lymnaea, life forms, Cr (III)ions, way of life, nutrition, digestion. Серед полютантів, які потрапляють із скидами чи стоками як у природні, так і у штучні водойми, одними з найнебезпечніших для гідробіонтів є іони важких металів. Актуальність дослідження впливу іонів важких металів на різні прояви життєдіяльності гідробіонтів пов’язана як із широкою розповсюдженістю їх наразі у поверхневих водах, так і з явно недостатнім на сьогодні ступенем дослідженості впливу значної частини із них на водних черевоногих молюсків. Саме до числа таких важких металів і належить Cr (III), рівень вмісту якого у гідромережі України. Уперше з’ясовановплив 0,5ГДКр –3ГДКр іонівCr (III) на спосіб життя, живлення і травлення Lymnaea vulnerata(Küster, 1862) i L. monnardi (Hartmann, 1844) –різних життєвих форм ставковиків гідромережі України. Внаслідок тривалого природного добору, котрий відбувався у цих тварин у вкрай відмінних екологічних умовах довкілля, адаптивна радіація черепашки прадавньої вихідної форми ставковиків здійснювалася реофілом L. monnardi і стагнофілом L. vulnerataу протилежно скерованих напрямках –дивергентно. Амплаподібна черепашка L. monnardi (сплющена, низька, компактна, обтічної форми, з великим устям) і велика плоска підошва ноги запобігають знесенням її течією, тоді як стагніколаподібна баштоподібна черепашка L. vulnerata(витягнутої форми, висока, вузька, з плоскими обертамизавитка і невеличким устям) надійно оберігає його від зайвих витрат води у процесі легеневого дихання, що важливо для цього звичайного мешканця здебільшого пересихаючих водойм, переживаючих умови десикації, забившись у щілини розтрісканого від пересиханнядна.Автохтонний кормовий раціон цих ставковиків представлений водоростями і вищою водяною рослинністю (різними за видовим складом щодо кожного з видів досліджених молюсків).За 0,5ГДКр, ГДКр, 2ГДКр, 3ГДКр іонів Cr (III) у середовищі у ставковиків розвивається 5-тифазний процес отруєння (0,5 ГДКр –байдужість; ГДКр і 2ГДКр –стимуляція; 3ГДКр –депресивна, сублетальна, летальна фази). Симптоматика його чітко ілюструється значеннями основних трофологічних показників у отруєних особин, залежних від перебігу у них відповідних фаз патологічного процесу.Ключові слова: Lymnaea, життєві форми, Cr (III), спосіб життя, живлення, травлення

A new Radix species from Qinling Mountains, China (Gastropoda: Lymnaeidae)

A new representative of the genus Radix has been recorded from eastern China, Radix dgebuadzei sp. nov. This peculiar species was recorded from the Qinling Mountains, a remote highland region sharing the high levels of faunal and floral endemism. The phylogeny indicate that the new species belongs to the Radix alticola species group, being sister to the widespread species R. plicatula (Yunnan and Gansu in China and Southeast Asia) and R. euphratica (Middle East, Central Asia, and Eastern Europe). At first glance, we could assume that Radix dgebuadzei sp. nov. represents a local lineage endemic to the Qinling Region, while this preliminary hypothesis needs to be confirmed in the future. Our novel discovery highlights that China harbors a largely endemic fauna of the Lymnaeidae and that isolated mountain ranges in East Asia could be considered evolutionary hotspots of the radicine pond snails.

Trophic characteristics of Lymnaea stagnalis (Mollusca: Gastropoda: Lymnaeidae) in toxic environment

The influence of ions of heavy metals (copper, cadmium, nickel, zinc, cobalt and manganese) was investigated on the basis of trophic characteristics: the average daily ration (ADR), and duration of food passage (DFP) of the Lymnaea stagnalis L. in various concentrations of toxicants in vivisection experiment. In addition to these indicators, the total amount of food consumed in the solutions with various concentrations of pollutants was found out during the chronic experiment and it was calculated for an individual (average monthly ration – AMR). It leads to the conclusions about the intensity of food consuming considering different levels of intoxication. In solutions with lethal concentrations, the death of animals occurs during the first day of its impact due to the damage of tissues and organ systems. Chronic lethal concentrations of toxicants inhibit the nutrition of pond snails dramatically. At the beginning of the experiment, solutions of heavy metals with sublethal concentrations give some stimulatory effect on the digestive system of molluscs that is replaced by its suppression in case of longer being in the toxic environment. The influence of toxicants within a subthreshold limit cannot be considered safe because of the cumulative properties of heavy metals – they become sublethal with prolonged exposure time.

Accumulation of heavy metals by family Lymnaeidae representatives as response to anthropogenic pollution critical levels of South Ural reservoirs

The features of heavy metals accumulation by Lymnaea fragilis and L . psilia were researched for the aerate emission polluted area of Karabash copper-smelting manufacturing (Southern Ural). These features are concluded with selective redistribution of heavy metals between soft tissues and the shell of Lymnaea . The heavy metals accumulation takes place by three independent tendencies: water soft tissues, water shell and soft tissues shell. The heavy metals content levels a thousand times exceed the physiological norm in soft tissues while in shell they exceed manifold. In the first place manganese and iron are accumulated while the cobalt, cadmium and molybdenum are finalizing the researched rank of accumulation. It has been ascertained that more biophil manganese are accumulated in mollusk soft tissues more than in other metals, while slightly less biophil iron is accumulated in shell, mainly in surface layers. For soft tissues and shell different ranks of heavy metals accumulation are observed, but these ranks are similar for different habitats, thus qualitative biogeochemical similarity is observed. The heavy metals accumulation in the system water soft tissues shell can help to estimate the extent of the metal environment pollution as well as local biophility of this metal. The adaptive response of pond snails to anthropogenic pollution is that there are more of them in less polluted reservoirs and less in more polluted reservoirs. It has been confirmed, that high heavy metals concentration and low pH level in reservoirs leads to death and absolute absence of these mollusk species.