Preface

Since the recent growth of molecular and genetic methods, and their implementation into organismic biology, zoology has been slowly regaining the importance it enjoyed until the late 1970's. Biologists are becoming increasingly aware that dynamic processes between molecules and proteins, the products of expressed genes, are relevant in the context of the whole organism's physiological status and behaviour. This modernization of organismic biology, however, has also resulted in more differentiation and diversity of methods within the disciplines that apply to the animal sciences. This increasing diversity within zoological disciplines was highlighted in the series of lectures held at our annual meeting in Halle in 2002.The highlight of the Halle meeting was undoubtedly the awarding of the Karl von Frisch Prize to F. G. Barth from Vienna University. Since Karl von Frisch's work few have so successfully exemplified the wealth of knowledge and insights that may be gained by applying modern methods, and convergent approaches from different disciplines to one single species. Barth's work focused on the wandering spiders Cupiennius. His lecture, “spider senses – technical perfection and biology” demonstrated to us the scientific power of a holistic approach.In the context of the behavioural studies of our colleagues at Halle University, Charlotte Helfrich-Förster presented a survey of “The circadian system of Drosphila melanogaster and its light input pattern”. Behavioural research on rhythms has its roots in Germany and enjoys a long tradition in zoology. As in many other disciplines, modern genetics opened up new and very fruitful insights into the subject.A greater understanding of the mechanisms of learning and memory is another field of research that has benefitted greatly from molecular biology. It has become a flourishing and expanding area of research, especially in invertebrate zoology. The current state of research, from a neurobiological and molecular point of view, was presented in three lectures, including one by Uli Müller, of the Berlin School. Cognition in audition, a still emerging field, was introduced to us in Bernhard Gaese's lecture on “Precognitive and cognitive elements in sound localization”. In the future, auditory cognition will surely become a Dorado for neurobiologists and acoustic psychologists. Susan D. Healy connected cognition with ecological constraints in her talk “Animal learning and memory: an integration of cognition and ecology”. She argued that cognitive performances can only be explained in the context of species-specific behaviours and ecology. “Cognitive ecology”, as it may be termed, is an emerging and genuinely zoological field of research that will have an important impact on our understanding of evolution. It's challenges will require highly motivated young zoologists.Research on species diversity takes a different approach to the subject of evolution and diversity, investigating the preconditions for speciation processes, and evolutionary trends and mechanisms. Unfortunately the fauna of soils is rarely considered, in spite of its great importance to ecological conditions. Richard Bagdett made up for this neglect in his lecture on the “Causes and consequences of biological diversity in soil”, and Bernhard Misof reported on speciation processes in Anisoptera.“Classical” physiology is still the backbone of organismic research. Modern versions of two very different topics were presented in Halle. Stephan Huber reported on the “Development of renal function”, and Fritz-Olaf Lehmann presented a new and convincing concept of aerodynamics and energetics in insect flight. His research continues the worthwhile tradition of flight analysis founded by Werner Nachtigall.The topics of our annual meeting in Halle could hardly have been more diverse. However, it is this the very diversity of modern and productive research field in zoology that characterizes a promising and fascinating future. In zoology, more than in any other biological discipline, exciting problems relevant to the understanding of evolution and its mechanisms are waiting to be solved by young scientists. Zoology has again become a start-up enterprise with promising rewards.     

Allochthonous resources are less important for faunal communities on highly productive,small tropical islands

Ecosystems are interconnected by energy fluxes that provide resources for the inhabiting organisms along the transition zone. Especially where in situ resources are scarce, ecosystems can become highly dependent on external resources. The dependency on external input becomes less pronounced in systems with elevated in situ production, where only consumer species close to the site of external input remain subsidized, whereas species distant to the input site rely on the in situ production of the ecosystem. It is largely unclear though if this pattern is consistent over different consumer species and trophic levels in one ecosystem, and whether consumer species that occur both proximate to and at a distance from the input site differ in their dependency on external resource inputs between sites. Using stable isotope analysis, we investigated the dependency on external marine input for common ground‐associated consumer taxa on small tropical islands with high in situ production. We show that marine input is only relevant for strict beach‐dwelling taxa, while the terrestrial vegetation is the main carbon source for inland‐dwelling taxa. Consumer species that occurred both close (beach) and distant (inland) to the site of marine input showed similar proportions of marine input in their diets. This supports earlier findings that the relevance of external resources becomes limited to species close to the input site in systems with sufficient in situ production. However, it also indicates that the relevance of external input is also species‐dependent, as consumers occurring close and distant to the input site depended equally strong or weak on marine input.     

Glycosyltransferases from Oat (Avena) Implicated in the Acylation of Avenacins

Plants produce a huge array of specialized metabolites that have important functions in defense against biotic and abiotic stresses. Many of these compounds are glycosylated by family 1 glycosyltransferases (GTs). Oats (Avena spp.) make root-derived antimicrobial triterpenes (avenacins) that provide protection against soil-borne diseases. The ability to synthesize avenacins has evolved since the divergence of oats from other cereals and grasses. The major avenacin, A-1, is acylated with N-methylanthranilic acid. Previously, we have cloned and characterized three genes for avenacin synthesis (for the triterpene synthase SAD1, a triterpene-modifying cytochrome P450 SAD2, and the serine carboxypeptidase-like acyl transferase SAD7), which form part of a biosynthetic gene cluster. Here, we identify a fourth member of this gene cluster encoding a GT belonging to clade L of family 1 (UGT74H5), and show that this enzyme is an N-methylanthranilic acid O-glucosyltransferase implicated in the synthesis of avenacin A-1. Two other closely related family 1 GTs (UGT74H6 and UGT74H7) are also expressed in oat roots. One of these (UGT74H6) is able to glucosylate both N-methylanthranilic acid and benzoic acid, whereas the function of the other (UGT74H7) remains unknown. Our investigations indicate that UGT74H5 is likely to be key for the generation of the activated acyl donor used by SAD7 in the synthesis of the major avenacin, A-1, whereas UGT74H6 may contribute to the synthesis of other forms of avenacin that are acylated with benzoic acid.     

Responses of solitary and colonial coronate polyps (Cnidaria, Scyphozoa, Coronatae) to sedimentation and burial

Coronate polyps retract their soft bodies into a protective peridermal tube after mechanical irritation. Sediment may enter the tube of contracted polyps, however, and block the opening [Jarms, G., 1990. Neubeschreibung dreier Arten der Gattung Nausithoe (Coronatae, Scyphozoa) sowie Wiederbeschreibung der Art Nausithoe marginata Kölliker, 1853. Mitt. Hamb. Zool. Mus. Inst. 87, 7-39; Silveira, F.L. da, Jarms, G., Morandini, A.C., 2003. Experiments in nature and laboratory observations with Nausithoe aurea (Scyphozoa: Coronatae) support the concept of perennation by tissue saving and confirm dormancy. Biota Neotropica 2 (2), 1-25]. In the present study, the ability of different coronate species [Nausithoe aurea Silveira and Morandini, 1997, Nausithoe planulophora (Werner, 1971), Thecoscyphus zibrowii Werner, 1984, Linuche unguiculata (Swarts, 1788)] to expel sediment particles from the tube was investigated. In laboratory experiments, sand grains and mussel shell fragments were inserted into the tubes and the responses of polyps were observed. Particles were ingested as polyps extended themselves, and after extension, they were defecated. Ingestion was effected by an aborally directed flagellar beat of the flagellated gastrodermal epithelia that was reversed for defecation. Particles only slightly smaller than the tube opening could be expelled, and extension of the polyp was possible even if grains blocked 2/3 of the tube. However, if particles became stuck in the tube, ingestion was impossible and polyp extension failed. Comparisons among the tested species showed that expulsion success depended on tube shape and polyp morphology. In N. aurea and N. planulophora, less than 5% of tubes were permanently blocked. The cave-dwelling species T. zibrowii was not able to ingest particles due to its particular morphology, and in 25% of experiments with shell fragments tubes were permanently blocked. Thin, elongate tubes of the colonial polyps L. unguiculata were also often permanently blocked by shell fragments (50%), but new polyps were developed from the scyphorhiza to ensure survival of the colony. Solitary polyps were able to survive more than 5 months retracted beneath any blocking particles. After tubes were cut off beneath such particles normal polyps developed. From our observations, we suggest that coronate polyps can exist in habitats with moderate sedimentation, and that they can survive being temporarily buried.