Petr Kočárek

Decomposition and Coleoptera succession on exposed carrion of small mammal in Opava, the Czech Republic

Abstract In 1997 and 1998, field studies on exposed rat carcasses were conducted in Opava, the Czech Republic, to describe the decomposition process and Coleoptera succession patterns. Coleoptera assemblages were monitored during three 40-d succession series conducted in spring, summer and autumn in two different habitats: meadow and deciduous forest. The rate of decomposition was studied in carcasses open to insects and isolated from them. The stages of decomposition recognised in this study follow Reeds classification: fresh, bloated, decay and dry stage. Carcass in summer decayed much faster than in spring and autumn and the decomposition of insect-free carcasses was less rapid than that of carcasses exposed to insects. A total of 145 Coleoptera species belonging to 22 families was recorded on the carcasses. The number of species in the succession series increased from the fresh stage, reached a maximum in the decay stage and gradually declined in the dry stage. The greatest diversity of Coleoptera was found in spring, followed by summer and autumn. More species were collected in forest site than in meadow. Four ecological groups, each characterised by a specific type of carrion association and varying in food specialisation and species biology, have been distinguished.

Diversification of mowing regime increases arthropods diversity in species-poor cultural hay meadows

Agricultural intensification reduces the biodiversity of European farmlands. Hay meadows represent an important farmland habitat, traditionally used to produce hay. With decreased demand for hay, the continuation of hay harvest is supported by Agri-environmental schemes across European Union. Modern hay harvest techniques differ from traditional manual harvest by removing the grass instantaneously over large land areas. To minimize adverse effects on meadow invertebrates, diversifying harvest operations is time and space is often recommended, but effects of such diversification are little studied. We compared the impact of uniform hay harvests with harvests executed in patchy manners, using four arthropod groups (butterflies, ground beetles, orthopterans and spiders) at productive, species-poor meadows in the Czech Republic. Butterflies, observed along transects, avoided uniformly cut units, preferring those cut as strips or blocks. In the three remaining groups, recorded using pitfall traps, a majority of species prevailed in traps located in uncut conditions. Synchronous mowing of large areas suppresses population sizes and diminishes the diversity of common arthropods. Besides of direct mortality and depletion of such resources as nectar or shelter, it synchronises sward regrowth, threatening also species requiring short-sward patches. Uniformly executed mowing contradicts the biodiversity conservation goal of Agri-environmental schemes. Diversifying the mowing operations via temporary fallows, or sequential mowing of land units, will improve the situation for common cultural meadows.

When the Body Hides the Ancestry: Phylogeny of Morphologically Modified Epizoic Earwigs Based on Molecular Evidence

Here, we present a study regarding the phylogenetic positions of two enigmatic earwig lineages whose unique phenotypic traits evolved in connection with ectoparasitic relationships with mammals. Extant earwigs (Dermaptera) have traditionally been divided into three suborders: the Hemimerina, Arixeniina, and Forficulina. While the Forficulina are typical, well-known, free-living earwigs, the Hemimerina and Arixeniina are unusual epizoic groups living on molossid bats (Arixeniina) or murid rodents (Hemimerina). The monophyly of both epizoic lineages is well established, but their relationship to the remainder of the Dermaptera is controversial because of their extremely modified morphology with paedomorphic features. We present phylogenetic analyses that include molecular data (18S and 28S ribosomal DNA and histone-3) for both Arixeniina and Hemimerina for the first time. This data set enabled us to apply a rigorous cladistics approach and to test competing hypotheses that were previously scattered in the literature. Our results demonstrate that Arixeniidae and Hemimeridae belong in the dermapteran suborder Neodermaptera, infraorder Epidermaptera, and superfamily Forficuloidea. The results support the sister group relationships of Arixeniidae+Chelisochidae and Hemimeridae+Forficulidae. This study demonstrates the potential for rapid and substantial macroevolutionary changes at the morphological level as related to adaptive evolution, in this case linked to the utilization of a novel trophic niche based on an epizoic life strategy. Our results also indicate that the evolutionary consequences of the transition to an ectoparazitic mode of living, which is extremely rare in earwigs, have biased previous morphology-based hypotheses regarding the phylogeny of this insect group.

Biology of Tetrix bolivari (Orthoptera: Tetrigidae)

The ecological requirements and biology of the Tetrigidae are almost unknown. The aim of the present work is to contribute to the knowledge of Tetrix bolivari, one of the least studied species of European Tetrigidae, by investigating its seasonal and daily activity, food biology, and vibratory communication. Adults of T. bolivari were found from March to September, with the greatest number of detections occurring between May and August. Based on the study of the daily activity patterns, most activities were positively correlated with temperature and negatively correlated with relative humidity. Detritus and mosses were the main components of the diet, with the most frequently consumed mosses being Bryum caespiticium and Bryum argenteum. Substrate-borne vibrational signals used in communication of T. bolivari are described here in detail for the first time. We distinguished four structural types of vibrational signals produced by males, including the signal produced by wing tremulation.

Seasonal variation in the diet of Tetrix tenuicornis (Orthoptera: Tetrigidae)

Many animals change their diet during the season according to food availability. The current field study determined whether the groundhopper Tetrix tenuicornis (Orthoptera: Tetrigidae), which specializes on moss and detritus, changes its diet during the season under conditions in which food components are constantly available. Dietary differences of T. tenuicornis were studied through the season, from May to October, by alimentary tract analyses. Detritus and moss (phylloids) dominated the alimentary tract contents, and other components were found in only minor amounts. The diversity of moss species in the alimentary tract varied during the season, and more moss species were consumed in spring and summer than in autumn. Diet was affected by developmental stage, sex (females consumed more food than males), population and abiotic factors. The rate at which detritus was consumed was significantly affected by the ambient temperature but the rate at which moss was consumed was mainly affected by relative humidity. Later instars consumed greater amounts of detritus than younger instars, and this difference corresponded to body size.

Age-related mandible abrasion in the groundhopper Tetrix tenuicornis (Tetrigidae, Orthoptera)

A study was conducted to determine whether the mandibles of the detrito-/bryophagous groundhopper Tetrix tenuicornis are subject to mechanical wear as a result of feeding, as is the case for grasshoppers that feed on silica-rich grasses. Abrasion was evaluated by measuring the length and width of the 3rd incisor and length of the 4th incisor in adults of different ages collected under natural conditions during one season. Although T. tenuicornis and other groundhoppers avoid feeding on grasses, we found that mandible abrasion increased with T. tenuicornis age. Age-related abrasion of the incisors of left and right mandibles was statistically significant in both sexes but the degree of abrasion was greater for females than males, apparently reflecting differences in the frequency and magnitude of feeding. Degree of abrasion also differed between right and left mandibles, probably because of differences in how each mandible is used during food processing. Abrasion of cuticular mandible structures may reduce the effectiveness of food processing late in the season.

Annotated checklist of the grasshoppers and crickets (Orthoptera) of the Czech Republic

A checklist is presented of the Orthoptera of the Czech Republic. Based on the critical revision of published data and previous lists of species, which often contained only general or questionable data and which often inaccurately cited each other, we found 96 species of Orthoptera belonging to the fauna of the Czech Republic. We emphasize those changes that are based on comparison with previous checklists. We provide information on missing, unclear, and extinct species and on newly detected species, and we confirm the status of species that have been missing for a long time (Leptophyes boscii, Polysarcus denticauda, Ruspolia nitidula, Eumodicogryllus bordigalensis, Tetrix bolivari, Mecostethus parapleurus). We also note those species for which only several individuals have been detected (Pteronemobius heydenii) or those survived only at a single locality (Platycleis montana, Aiolopus thalassinus, Dociostaurus brevicollis, Omocestus petraeus) or at two localities (Poecilimon intermedius, Platycleis veyseli, Pseudopodisma nagyi). Phaneroptera nana is recorded as new for Bohemia.

Substrate-borne Vibrations as a Component of Intraspecific Communication in the Groundhopper Tetrix ceperoi

Substrate-borne vibrational signals used in communication of Tetrix ceperoi (Orthoptera: Tetrigidae) are described for the first time. Among all studied Tetrix species, T. ceperoi use the richest repertoire of vibrational signals. These signals consist of isolated pulses or pulses united into rhythmically repeated or irregularly repeated groups and are used in rivalry, pre-copulation, and copulation behaviour (1st, 3rd, and 4th structural types of signals), and are also used by single males or females (2nd type of signal). A 5th type of vibrational signal is produced by wing tremulation, which was unknown Tetrigidae. Based on the results of this study, the vibrational signalisation seems to play an important role in species-specific mate recognition of T. ceperoi. The significance of individual signals is discussed based on results of manipulative contact experiments.

Weather-dependent microhabitat use by Tetrix tenuicornis (Orthoptera: Tetrigidae).

For ectothermic animals, selection of a suitable microhabitat is affected by a combination of abiotic and biotic factors. Also important is the trade-off between those microhabitats with optimal microclimatic conditions and food availability vs. those with the lowest level of competition and lowest risk of predation. Central European species of groundhoppers (Orthoptera: Tetrigidae) live in locations with small-scale mosaics of patches formed by bare ground, moss cushions and vascular plants (grasses and forbs). Our research focused on the effects of selected weather components (current temperature, humidity, atmospheric pressure and sunlight) on specific microhabitat selection by adults (during the reproductive season) and by the last-instar nymphs (during the non-reproductive season) of the groundhopper Tetrix tenuicornis. Using experimental conditions, we determined that microhabitat use by T. tenuicornis is sex-specific and that microhabitat preference differs between adults and nymphs. We suppose that microhabitats are used according to groundhopper current needs in relation to each habitat’s suitability for maintaining body temperature, food intake and reproductive behaviour. Microhabitat preferences were significantly associated with temperature and atmospheric pressure. Changes in atmospheric pressure signal changes in weather, and insects respond to increases or decreases in pressure by adjusting their behaviour in order to enhance survival. We propose that, under low atmospheric pressure, T. tenuicornis actively seeks microhabitats that provide increased protection from adverse weather.

Euborellia annulipes (Dermaptera: Anisolabididae), a new alien earwig in Central European greenhouses : potential pest or beneficial inhabitant?

Abstract Extensive research was undertaken from 2010 to 2013 that focused upon the invertebrate fauna occurring in greenhouses of the botanical and zoological gardens in Czech Republic and Slovakia. Occurrences of the alien earwig, Euborellia annulipes (Lucas, 1847), were found in three greenhouses in Czech Republic, and these findings are the first to document established populations in Central European greenhouses. The spectrum of foods consumed by E. annulipes was studied with a post-mortem analysis of the gastrointestinal tract contents. Based on the analyses, we can conclude that E. annulipes is an omnivorous species that, in greenhouse conditions, predominantly feeds on plant tissue. Despite the fact that E. annulipes also feeds on invertebrates, our study points to a small proportion of such food in its diet under free-choice conditions in greenhouses. According to the large portion of plant tissues in the species’ diet, it could potentially be a pest of cultivated plants, especially seedlings and young plants with soft tissue.