ALEKSANDRO STULGINSKIO UNIVERSITETAS Povilas Mulerčikas SPRAGŠIŲ (COLEOPTERA, ELATERIDAE) PAPLITIMAS SKIRTINGOSE AGROCENOZĖSE IR GAUSIAUSIŲ RŪŠIŲ ŽALINGUMAS MIGLINIAMS JAVAMS Daktaro disertacijos santrauka Žemės ūkio mokslai (A 000), agronomija (01 A) Akademija, 2013 Disertacija rengta 2008–2012 metais Aleksandro Stulginskio universitete. Mokslinis vadovas: Doc. dr. Vytautas Tamutis (Aleksandro Stulginskio universitetas, žemės ūkio mokslai, agronomija – 01 A). Disertacija ginama Aleksandro Stulginskio universitete Agronomijos mokslo krypties taryboje: Pirmininkas: Prof. habil. dr. Zenonas Dabkevičius (Lietuvos agrarinių ir miškų mokslų centras, žemės ūkio mokslai, agronomija 01 A). Tarybos nariai: Doc. dr. Aušra Marcinkevičienė (Aleksandro Stulginskio universitetas, žemės ūkio mokslai, agronomija 01 A). Dr. Jolanta Rimšaitė (Ekologijos institutas, Gamtos tyrimų centras, biomedicina, zoologija 05B). Prof. habil. dr. Rimantas Rakauskas (Vilniaus universitetas, biomedicina, zoologija 05B). Prof. dr. Kęstutis Romaneckas (Aleksandro Stulginskio universitetas, žemės ūkio mokslai, agronomija – 01 A) Oponentai: Prof. habil. dr. Jonas Rimantas Stonis (Lietuvos edukologijos universitetas, biomedicina, zoologija 05B). Prof. dr. Vytautas Pilipavičius (Aleksandro Stulginskio universitetas, žemės ūkio mokslai, agronomija 01 A). Disertacija bus ginama viešajame Agronomijos mokslo krypties tarybos posėdyje 2013 m. gruodžio 19 d., 14 val. Aleksandro Stulginskio universiteto IV rūmų posėdžių salėje (211 kab.), Adresas: Universiteto g. 8 A, Akademijos mstl., LT – 53361, Kauno r. tel.: (8–37) 752 254, faks.: (8-37) 397 500. Daktaro disertacijos santrauka išsiuntinėta 2013 m. lapkričio 19 d. Disertaciją galima peržiūrėti Aleksandro Stulginskio universiteto ir Lietuvos agrarinių miškų mokslų centro, Žemdirbystės instituto bibliotekose. 2 INTRODUCTION Relevance of the topic. Species composition, distribution, habitat preference of click beetle detected in Lithuanian agrocenoses, their need for certain soil properties and as well as food ration has not been yet fully explored in Lithuania. Every year, farmers suffer huge losses in relation to damage caused by click beetle larvae. They injure germinating seeds of the variety of plants, seedlings, underground parts of the plants, tubers, and roots. Damaged seeds do not sprout up, seedlings perish, and crops become sparse. The trade value gets worse and fungal or bacterial infection pervades through the injuries into potato tubers or vegetables during the storage period and finally the stored production gets rotten. There is a lack of data concerning click beetle bioecology and harmfulness under Lithuanian environmental conditions. In order to increase the efficacy of plant protection measures against these pests it is necessary to establish prevalent click beetle species composition, to explore their bioecological characteristics and the level of harm in agrocenoses under Lithuanian agroclimatic conditions. On the other hand, not every click beetle species is herbivorous and makes damage. There are species which are recognized as predators. In this respect, they may be eligible as natural enemies of pests for an integrated pest management approach. Hypothesis of the research. Click beetle species composition, distribution and abundance should depend on granulometric structure of soil and on the state of agrocenosis as well. It is likely that the variety of click beetle species and the abundance of individuals are greater in agrocenoses with lighter granulometric structure of the soil and minimal tillage. Click beetle larvae are characterized as polyphagous. Thus larvae of all click beetle species should be equally destructive to cereals. Objective of the research – to determine composition, distribution, abundance dynamics of the click beetle species detected in Lithuanian agrocenoses, and harmfulness of the most abundant species for certain cereals. Tasks of the research. It was pursued by the research: 1. To determine in agrocenoses with different granulometric structure of the soil and different soil tillage: 1.1. Click beetle species composition and its alterations; 1.2. Abundance of click beetle individuals and its alterations; 1.3. Dynamics of the number of click beetle specimens during the growing period and in the process of succession; 2. To evaluate the harmfulness of the most common in agrocenoses click beetle species to maize, wheat and barley under laboratory conditions. Propositions to be defended: 1. Click beetle species composition depends on the soil granulometric structure and the state of agrocenosis has no significant effect. 2. Abundance of click beetle individuals depends on the soil granulometric structure and on the state of agrocenosis. 3. Duration of the activity period and dynamics of adult click beetles is more dependent on biological characteristics of the species than on the ambient air temperature. 3 4. Harmfulness of larvae of various click beetle species is different for maize, wheat and barley, and its intensity depends on the number of click beetle larvae in the substrate. Originality of the research work. For the first time under Lithuanian agroclimatic conditions, click beetle species composition that were detected in agrocenoses, their distribution, abundance and alterations have been established in agrocenoses with different state in loamy soil (Calc(ar)i- Epihypogleyic Luvisol LV-g-p-w-cc (sc)), sandy soil (SDp-n Dystri- Haplic Arenosols (Arh-dy)), hard loamy clay soil (RDg-8-k2- Eudocaleari- Epihypogleyic Cambisols (CMg-p-w-can)), and sandy loam soil (SDp-b Eutri- Haplic Arenosols (Arh-eu)). The harmfulness of click beetle species Agiotes obscurus, Selatosomus aeneus, Cidnopus aeruginosus for maize, wheat and barley under laboratory conditions has been evaluated. Studies have demonstrated that Cidnopus aeruginosus injures all investigated plants, however their damage is two times fewer than caused by A. obscurus and S. aeneus larvae. Practical value of the research. Every year, due to the damage caused by click beetles farmers suffer huge losses. Conventional plant protection measures including chemicals are not effective enough due to specific click beetle larvae lifestyle. Pursuing better plant protection against these pests the necessity of the development of crop cultivation strategies considering bioecology of both the crop and click beetles injuring the crop. Results of the research which revealed that the composition of click beetle species and their abundance depend on soil type and agrocenosis state will enable more appropriate selection of composition of cultivated plant species in order to avoid yield losses. The peculiarities of the abundance dynamics of click beetle adults were clarified due to investigations which will enable more efficient application of chemical plant protection measures against these pests. The established harmfulness of the most common click beetle species in agrocenoses will launch a more accurate determination of the economic damage threshold for these pests. Approval of the research work. Three articles concerning topic of the dissertation have been published, and one among them is the publication, which is assessed in the database of the Institute for Scientific Information (ISI WOS) with a citation index. The other two articles have been published in journals which are refereed by the database of the Institute for Scientific Information (ISI Master Journal List). The results of the research have been presented at The Fifth International Scientific Conference “Research and Conservation of Biological Diversity in Baltic Region” (Latvia, Daugavpils, 2009) and at the Twenty-eighth Nordic-Baltic Congress of Entomology “XXVIII Nordic-Baltic Congress of Entomology” (Lithuania, Birštonas, 2010). The structure of the dissertation. The dissertation is written down in Lithuanian. The work consists of the following parts: introduction, literature review, research conditions and methods, results, conclusions, list of references on the topic and summary in English. The volume is - 121 pages, 8 tables, 31 figures, 365 references have been cited. 4 EXPERIMENTAL OBJECT, CONDITIONS AND METHODS Experimental object – click beetles prevalent in agrocenoses in the Republic of Lithuania (Coleoptera, Elateridae). Experimental site and soil type. Investigations were carried out in 2009-2012 in Kaunas, Marijampolė and Druskininkai regions with four different types of soil in agrocenoses. Four stationary sites according to the granulometric structure of the soil were selected with four different soil types as follows: sandy soil (A1) (SDp-n Dystri- Haplic Arenosols (Arh-dy)), sandy loam soil (A2) (SDp-b Eutri- Haplic Arenosols (Arh-eu)), loamy soil (A3) (Calc(ar)i- Epihypogleyic Luvisol LV-g-p-w-cc (sc)), hard loamy clay soil (A4) (RDg-8-k2- Eudocaleari- Epihypogleyic Cambisols (CMg-p-w-can)) (Table 1). Table 1. Soil characteristics of the research locations, 2009–2012 Coordinates Quantity of the mobile nutrients pH Soil type of the Nitrogen Potassium Phosphorus of (by Buivydaitė et al., 2001) locations (N %) (K2O) (P2O5) the (WGS mg/kg mg/kg soil system) A1 (SDp-n Dystri- Haplic 54°53'46"N, 0.17 73.8 117.1 5.37 Arenosols (Arh-dy)) 23°29'02"E A2 (SDp-b Eutri- Haplic Arenosols 54°5'28"N 0.24 168.6 190.2 6.6 (Arh-eu)) 23°51'39"E A3 (Calc(ar)i- Epihypogleyic 54°53'06"N 0.21 86.4 46.7 6.65 Luvisol LV-g-p-w-cc (sc)) 23°50'15"E A4 (RDg-8-k2- Eudocaleari- 54°29'33"N 0.48 152.4 40.0 7.0 Epihypogleyic Cambisols (CMg-p- 23°44'31"E w-can)) The research