Mravenec lužní (Liometopum microcephalum) dosahuje na jižní Moravě (v jihovýchodních Čechách) severozápadní hranice svého rozšíření, a druhu se tak dostávalo velké pozornosti mezi českými přírodovědci. Mnohé informace publikované v literatuře nebo na internetu však jsou spíše mýty než fakta. O areálu druhu se často uvádí, že se rozkládá od Iberského poloostrova do východní Evropy a nejzápadnější části Asie, někdy dokonce až na ruský Dálný východ. Ve skutečnosti neexistují žádné doklady o historickém ani současném výskytu mravence lužního na západ od Alp (severní Itálie). Populace na Dálném východě byla již před dlouhou dobou odlišena jako samostatný druh. Článek detailně popisuje historické a současné rozšíření tohoto mravence na jižní Moravě. Ačkoli jde o nejsevernější populaci druhu, populace na Ukrajině a v Rusku dosahují téměř stejné zeměpisné šířky. Mravenec lužní kolonizuje staré, ale živé stromy s dutinami, zpravidla duby, v lesích i mimo les. Na severní hranici svého areálu dává jednoznačně přednost lužním stanovištím, na jihu je preferuje mnohem méně. Jasné doklady uváděné ochrany hnízdních stromů mravenčími koloniemi scházejí. Přes protichůdné názory publikované v literatuře tvoří trofobióza významnou součást potravní strategie druhu, ale stanovení důležitosti jednotlivých složek potravy stále chybí. Druh se vyznačuje jasným polymorfismem dělnic, ale stupeň polymorfismu se liší mezi koloniemi, mění se v průběhu roku a také závisí na podmínkách prostředí, jako je přítomnost silných kompetitorů. Mnohé otázky týkající se biologie a ekologie mravence lužního zatím zůstávají nezodpovězeny., The arboricolous ant Liometopum microcephalum, which reaches the north-western edge of its range in South Moravia (south-eastern Czechia), has been receiving substantial attention by Czech naturalists. However, many pieces of information presented in the literature or on the internet are more myth then fact. Its range is often reported to reach from the Iberian Peninsula to Eastern Europe and western-most Asia, sometimes even to the Russian Far East. In fact, there is no evidence of its historic or present occurrence west of the Alps (northern Italy). The Far Eastern population has been recognized as a separate species a long time ago. The historic and current range in South Moravia is described in detail. Although being indeed the northern-most population of the species, populations in the Ukraine and Russia reach almost the same latitude. Old but living trees with cavities, mostly oaks, are colonized both in and outside of forests. There is a clear preference for alluvial habitats in the northern part of its range, much less so in the south. There is hardly any evidence for the reported protection of nest trees by its ant colonies. Despite contrary opinions published, trophobiosis is an important part of the species’ foraging behaviour, but an assessment of the importance of different components of its diet is still lacking. Worker polymorphism is apparent but its degree varies among colonies and changes in the course of the year and also mirrors environmental variables such as the presence of strong competitors. Many questions regarding the species’ biology and ecology remain open., and Jiří Schlaghamerský, Lenka Petráková.
1_The arboricolous dolichoderine ant Liometopum microcephalum (Panzer, 1798) is considered to be mainly predatory, although there are some reports of it tending aphids. The main objective of the present study was to confirm that this ant has a trophobiotic relationship with aphids and assess seasonal differences in its utilization of honeydew. We hypothesized that the worker ants on trees where they have their nest (nest tree) and trees where they are foraging (foraging trees) should differ in gaster mass and sugar content depending on their direction of movement, and that both should be highest in spring. From spring to summer 2009, ascending and descending workers were collected from nest and foraging trees at a locality in South Moravia, Czech Republic. Mass of their gasters and their content of total and reducing sugars were measured using chemical (photometric) methods. Differences in gaster mass confirmed the flow of liquid food from foraging to nest trees, but there were no significant between-month differences. Contents of total and reducing sugars were positively correlated with gaster mass. The gasters of workers descending from foraging trees contained significantly more reducing sugars than those of workers descending or ascending nest trees. The content of reducing sugars was lowest at the beginning of the ants’ activity period in April and highest in June, with a non-significant drop in July. Results for total sugars were similar, with the decrease in July being significant. The concentration of sugars in the gasters of workers ascending and descending nest trees did not differ significantly but the absolute content of total sugars was higher in the gasters of ascending ants., 2_Results from foraging trees confirmed that the ants collected the honeydew from these trees. Possible reasons for the ambigous results for nest trees are discussed. We conclude that trophobiosis is an important component of the nutritional biology of L. microcephalum., Jiří Schlaghamerský ... []., and Obsahuje seznam literatury