Investigations of the interactions between aphids and ants in multispecies ant communities and an experimental investigation of some ethological aspects of ant-aphid interactions were carried out in mixed forests at Novosibirsk Academic Centre, from 1998-2002. The eight species of ants investigated were characterized by different levels of territorial organization and interaction with aphids, which were associated with different degrees of specialization of the worker ants. The most myrmecophilous species of aphids (24 out of 33 species identified) were associated with the red wood ants. By placing Coccinella septempunctata Linnaeus (Coleoptera: Coccinellidae) in aphid colonies it was shown that only ants with large protected territories attacked the adults and larvae of the predator. Other species of ants either protected aphids only from adult ladybirds or did not guard them at all. Moreover, only individuals of Formica s. str., which has specialized workers, did not switch to collecting protein food. However, aphids make up a considerable part of the prey of ants, in which non-myrmecophilous aphids predominate (about 60-100% of the aphid prey). Moreover, ants only killed unattended or damaged myrmecophilous aphids. Formica s. str., which has the highest level of social and territorial organization, provides aphids with the most services and is the dominant species forming symbiotic relationships with aphids in the communities studied.
Arbuscular mycorrhizal fungi (AMF) form symbioses with many plants. Black locust (Robinia pseudoacacia L.) is an important energy tree species that can associate with AMF. We investigated the effects of AMF (Rhizophagus irregularis and Glomus versiforme) on the growth, gas exchange, chlorophyll (Chl) fluorescence, carbon content, and calorific value of black locust seedlings in the greenhouse. The total biomass of the arbuscular mycorrhizal (AM) seedlings was 4 times greater than that of the nonmycorrhizal (NM) seedlings. AMF greatly promoted the photosynthesis of black locust seedlings. AM seedlings had a significantly greater leaf area, higher carboxylation efficiency, Chl content, and net photosynthetic rate (PN) than NM seedlings. AMF also significantly increased the effective photochemical efficiency of PSII and significantly enhanced the carbon content and calorific value of black locust seedlings. Seedlings inoculated with G. versiforme had the largest leaf area and highest biomass, Chl content, PN, and calorific value., X. Q. Zhu, C. Y. Wang, H. Chen, M. Tang., and Obsahuje bibliografii
The amphibious plant species of intermittent aquatic habitats thrive both submerged and emerged. In order to outline the adaptive characters of these two life forms photochemical efficiency of photosystem 2, leaf contents of chlorophyll (Chl) a and b, carotenoids (Car), anthocyanins (Ant), and UV-B absorbing compounds (UV-B abs), and root aerenchyma and arbuscular mycorrhizal (AM) colonisation were studied in Glyceria fluitans, Gratiola officinalis, Ranunculus lingua, Teucrium scordium, Sium latifolium, Sparganium emersum, and Veronica anagallis-aquatica. Water level fluctuations did not exert a severe effect on photon harvesting efficiency. Submerged specimens had higher contents of Car and Ant whereas higher contents of UV-B abs were found in emerged specimens indicating efficient protection against the harmful effects of solar radiation. Roots of all species studied had extensive aerenchyma and were colonised by AM fungi, which were significantly more abundant in emerged specimens. This is the first report on AM symbiosis in S. latifolium and S. emersum. and N. Šraj-Kržič ... [et al.].
Většina krevet čeledi Palaemonidae obývajících tropická a subtropická moře Atlantského, Indického a Tichého oceánu se adaptovala k symbiózám se zástupci řady kmenů bezobratlých živočichů. Nejširší zastoupení symbiotických krevet je mezi těmi, které jsou ektosymbioticky vázány na těla žahavců, je mezi nimi i řada čističů ryb. Známa jsou i podobná soužití s ostnokožci, ale najdeme je i jako endosymbionty v mořských houbách, mlžích a v sumkách. Evoluce těchto korýšů byla zjevně úzce spojena se změnou hostitelských organizmů. Systematikou, ekologií a fylogenezí symbiotických krevet se zabývá tým Katedry biologie a ekologie PřF Ostravské univerzity., The majority of shrimp that belong to the Palaemonidae family (found in tropical and subtropical seas of the Atlantic, Indian and Pacific Oceans) live in symbioses with various invertebrate hosts. Most frequent are ecto-symbioses with cnidarians, including several cases of fish-cleaners. Similar associations are known with echinoderms, and other remarkable examples include endo-symbioses of shrimp with sponges, shrimp with bivalve molluscs, and shrimp with ascidians. Evolution of those shrimp was, evidently, closely related to multiple host-switching events. The systematics, ecology, and phylogeny of symbiotic shrimp are studied by a team from the University of Ostrava., and Zdeněk Ďuriš.
To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is a polyphagous herbivore and a world-wide pest in agricultural crops. With bacteria in the gut, the thrips larval development time can be shorter and its oviposition rate higher compared to bacteria-free thrips. Bacteria are not directly transmitted from mother to offspring, but larvae acquire bacteria from the leaves right after they hatch. These gut bacteria are present on the leaves on feeding sites used by other thrips before the larvae arrive, probably because these other thrips have deposited bacteria via faeces or regurgitation. In this study we addressed the question whether the transmission route of symbiotic bacteria influences the thrips feeding behaviour, and determined the feeding and oviposition preference of thrips, by giving them a choice between leaves with and leaves without prior grazing by other western flower thrips. This was studied for thrips with and thrips without gut bacteria. Young larvae prefer to feed on leaves that where grazed before by other thrips and females prefer to oviposit on these grazed leaves. These results are in contradiction to earlier studies that have found that thrips larvae fitness is lower on thrips damaged plants than on clean plants. This behaviour does however promote the establishment of gut bacteria in the thrips. The factors determining the preference for thrips-damaged leaves may be the physical leaf damage or odours that are produced by the plant, the bacteria or both.