Has .i.Tilia x euchlora./i. a detrimental effect on soil annelids in urban greens?

The potential effect of the exotic linden .i.Tilia x euchlora./i., widely planted in urban greens, on soil-dwelling annelids (Lumbricidae, Enchytraeidae) was investigated in two parks in the city of Brno, Czech Republic. Linden trees are the source of honeydew that might affect soil biota and remains an important input of these trees into the soil compartment even if litter is being removed as part of the park management. There have also been discussions about the alleged toxicity of .i.T. x euchlora./i. nectar to pollinators. The native .i.T. platyphyllos./i. was used as a control. Within two days in November 2006 annelids were sampled at three different distances (1 m, 3 m, 6 m) along transects from the trees to well developed lawns. Earthworms were extracted by the electrical-octet method, enchytraeids by wet funnel extraction from soil cores taken down to 12 cm

Interactions between Liometopum microcephalum (Formicidae) and other dominant ant species of sympatric occurrence

Interactions of Liometopum microcephalum with other two territorial ants also nesting in or foraging on trees, Lasius fuliginosus and Formica rufa, were studied in South Moravia (Czech Republic), at the northwestern border of its range, in 2005–2009. L. microcephalum defends its nest and foraging trees. Its distribution area is fragmented and in the north restricted to river floodplains. We investigated whether competition by other behaviourally dominant ant species could limit its distribution. We found six sites where nests of potential competitors were situated close to a L. microcephalum nest tree. We studied the partitioning of space (occupancy of foraging trees) between the species by observation and by lines of pitfall traps placed between nest trees of L. microcephalum and L. fuliginosus. These species avoided each other; the territory border changed over time. Worker interactions, including combats between L. microcephalum and F. rufa colonies, were observed in the field. Aggressive behaviour occurred close to the nest, on trails, foraging trees, and occasionally at food baits. In such situations, L. microcephalum took advantage of worker cooperation. Encounters of single workers were observed in laboratory experiments. L. microcephalum, attacking primarily by biting, lost almost all combats with L. fuliginosus, being paralysed by its secretions. One-on-one encounters with F. rufa led less frequently to combat and chances were more even, but F. rufa prevailed more often. We confirmed the territorial behaviour of L. microcephalum. In the rare situations, in which its colonies occurred together with other territorial species, we observed conflicts but no total displacement of one species by another

Beetles “in red”: are the endangered flat bark beetles Cucujus cinnaberinus

Two native species of the genus Cucujus show a wide geographic distribution in Europe, Cucujus cinnaberinus (Scopoli, 1763) and C. haematodes Erichson, 1845. Although data on the distribution and ecology of these rare and endangered species are increasing, there are few reports on their biology and behaviour, and some aspects of their feeding ecology remain problematic. Our aim was to study, for the first time, the cuticular chemical profiles of these two beetles to (i) investigate the presence of chemicals potentially involved in defence by pathogens and (ii) lay the foundation for understanding the role of their bright red colour. The analysis of the cuticular profile was performed in-vivo by solid phase microextraction coupled with gas chromatography-mass spectrometry. In the cuticular profiles of the two species we identified 24 compounds belonging to different classes of molecules, i.e. hydrocarbons, aldehydes, esters, n-alkyl morpholines, and a high number of organic acids. Qualitative differences in terms of both signal intensity and detected compounds were found between the two species. As reported in other insects, the remarkable array of avoidance substances suggests a strict relationship with the bright red colour of the adults, which probably acts as an aposematic or warning signal. European Cucujus species are probably well protected against enemies because some identified chemicals, particularly fatty acids, are related to an anti-predatory strategy to fight off predators that use their sense of smell to locate their prey. Other substances found on the cuticular layer of these beetles are probably involved in an antimicrobial and antifungal function, as demonstrated in other insects living in habitats that host many pathogens

The effects of polycyclic aromatic hydrocarbons and heavy metals on terrestrial annelids in urban soils O efeito de hidrocarbonetos aromáticos policíclicos e metais pesados em anelídeos terrestres de solos urbanos

The effect of soil contamination by polycyclic aromatic hydrocarbons (PAH) and heavy metals on earthworms and enchytraeids was studied in urban parks, in Brno, Czech Republic. In spring and autumn 2007, annelids were collected and soil samples taken in lawns along transects, at three different distances (1, 5 and 30 m) from streets with heavy traffic. In both seasons, two parks with two transects each were sampled. Earthworms were collected using the electrical octet method. Enchytraeids were extracted by the wet funnel method from soil cores. All collected annelids were counted and identified. Basic chemical parameters and concentrations of 16 PAH, Cd, Cu, Pb, and Zn were analysed from soil from each sampling point. PAH concentrations were rather low, decreasing with the distance from the street in spring but not in autumn. Heavy metal concentrations did not decrease significantly with increasing distance. Annelid densities did not significantly differ between distances, although there was a trend of increase in the number of earthworms with increasing distance. There were no significant correlations between soil content of PAH or heavy metals and earthworm or enchytraeid densities. Earthworm density and biomass were negatively correlated with soil pH; and enchytraeid density was positively correlated with soil phosphorus.<br>O efeito da contaminação do solo por hidrocarbonetos aromáticos policíclicos (PAH) e metais pesados em minhocas e enquitreídeos foi estudado em parques urbanos, em Brno, República Tcheca. Na primavera e outono de 2007, os anelídeos foram coletados, e amostras de solo foram retiradas de gramados ao longo de transectos, em três diferentes distâncias (1, 5 e 30 m) de ruas com muito tráfego. Nas duas estações, foram amostrados dois parques com dois transectos cada um. As minhocas com uso do método do octeto elétrico, e os enquitreídeos foram extraídos das amostras de solo pelo método do funil úmido. Todos os anelídeos coletados foram contados e identificados. Parâmetros químicos básicos e concentrações de 16 PAHs, Cd, Cu, Pb e Zn, de cada ponto de amostragem, foram analisados. As concentrações de PAH foram relativamente baixas, e decresceram na primavera, mas não no outono, com a distância da rua. As concentrações de metais pesados não diminuíram significativamente com o aumento da distância. As densidades de anelídeos não diferiram significativamente entre as distâncias, mas houve tendência de aumento no número de minhocas, com o aumento da distância. Não houve correlação significativa entre o conteúdo de PAH ou metais pesados do solo com as densidades de minhocas e enquitreídeos. A densidade e a biomassa das minhocas foram negativamente correlacionadas ao pH do solo; e a densidade de enquitreídeos foi positivamente correlacionada ao conteúdo de fósforo no solo