Year of publication
- The biodiversity network BioFrankfurt: an innovative strategic approach to integrative research, conservation, and education (2009)
- Responding to inadequate awareness of the outstanding importance of biodiversity, the BioFrankfurt network was founded in 2004 in the State of Hesse, Germany. It is presented here as a case study and may serve as a model for other parts of the world, such as the Middle East. In 2007, only about 26% of the German population were familiar with the term “Biodiversity”, and most of them only had a vague idea about its meaning. The BioFrankfurt network of institutions addressed this problem, raising public awareness and supporting research, education and conservation. A regional biodiversity education program has been developed and delivered to more than 500 schools. Since 2007, an innovative public relations campaign combines raising awareness on regional biodiversity issues with activities to improve the public image of the Frankfurt area. Because of its geographical focus, the network’s activities gained the attention of local and regional politicians and other decision makers, culminating in the joint establishment of a new Biodiversity and Climate Research Centre by BioFrankfurt member institutions. The success of current activities attracts interesting partners, resulting in challenging cooperation initiatives. The authors are convinced that the network’s concepts and activities have a great potential to profoundly enhance the notion and acceptance of biodiversity issues elsewhere. Keywords: BioFrankfurt, biodiversity network, education, public awareness, scientifi c communication
- When Indian crabs were not yet Asian - biogeographic evidence for Eocene proximity of India and Southeast Asia (2010)
- Background: The faunal and floral relationship of northward-drifting India with its neighboring continents is of general biogeographic interest as an important driver of regional biodiversity. However, direct biogeographic connectivity of India and Southeast Asia during the Cenozoic remains largely unexplored. We investigate timing, direction and mechanisms of faunal exchange between India and Southeast Asia, based on a molecular phylogeny, molecular clock-derived time estimates and biogeographic reconstructions of the Asian freshwater crab family Gecarcinucidae. Results: Although the Gecarcinucidae are not an element of an ancient Gondwana fauna, their subfamily Gecarcinucinae, and probably also the Liotelphusinae, evolved on the Indian Subcontinent and subsequently dispersed to Southeast Asia. Estimated by a model testing approach, this dispersal event took place during the Middle Eocene, and thus before the final collision of India and the Tibet-part of Eurasia. Conclusions: We postulate that the India and Southeast Asia were close enough for exchange of freshwater organisms during the Middle Eocene, before the final Indian--Eurasian collision. Our data support geological models that assume the Indian plate having tracked along Southeast Asia during its move northwards.
- From sea to land and beyond : new insights into the evolution of euthyneuran Gastropoda (Mollusca) (2008)
- Background The Euthyneura are considered to be the most successful and diverse group of Gastropoda. Phylogenetically, they are riven with controversy. Previous morphology-based phylogenetic studies have been greatly hampered by rampant parallelism in morphological characters or by incomplete taxon sampling. Based on sequences of nuclear 18S rRNA and 28S rRNA as well as mitochondrial 16S rRNA and COI DNA from 56 taxa, we reconstructed the phylogeny of Euthyneura utilising Maximum Likelihood and Bayesian inference methods. The evolution of colonization of freshwater and terrestrial habitats by pulmonate Euthyneura, considered crucial in the evolution of this group of Gastropoda, is reconstructed with Bayesian approaches. Results We found several well supported clades within Euthyneura, however, we could not confirm the traditional classification, since Pulmonata are paraphyletic and Opistobranchia are either polyphyletic or paraphyletic with several clades clearly distinguishable. Sacoglossa appear separately from the rest of the Opisthobranchia as sister taxon to basal Pulmonata. Within Pulmonata, Basommatophora are paraphyletic and Hygrophila and Eupulmonata form monophyletic clades. Pyramidelloidea are placed within Euthyneura rendering the Euthyneura paraphyletic. Conclusion Based on the current phylogeny, it can be proposed for the first time that invasion of freshwater by Pulmonata is a unique evolutionary event and has taken place directly from the marine environment via an aquatic pathway. The origin of colonisation of terrestrial habitats is seeded in marginal zones and has probably occurred via estuaries or semi-terrestrial habitats such as mangroves.
- Isolation by distance in a population of a small land snail Trochoidea geyeri: evidence from direct and indirect methods (1996)
- Population structure was estimated in a continuous population of a small land snail (Trochoidea geyeri). Mark-recapture experiments and randomly amplified polymorphic DNA analyses indicate that the population structure can be described by the isolation by distance model of Wright (1946). Estimates of density and dispersal suggest a neighbourhood size of 70-208 individuals on an area of 13-21 m 2 . A principal component analysis of the randomly amplified polymorphic DNA data reveals clinal variation of genetic composition across the population, as predicted by the neighbourhood concept. An analysis of molecular variance indicates substantial genetic structuring. Comparisons of the genetic distances, expressed as euclidean distances among individuals, versus the geographic distance between sampling sites yield a highly significant positive correlation (Mantel test: r = 0.567, p<0.0001). The revealed pattern of populational subdivision on a microgeographic scale seems to be one of the principal processes generating and maintaining genetic diversity within populations of small land gastropods.
- Comparing the efficacy of morphologic and DNA-based taxonomy in the freshwater gastropod genus Radix (Basommatophora, Pulmonata) (2006)
- Background Reliable taxonomic identification at the species level is the basis for many biological disciplines. In order to distinguish species, it is necessary that taxonomic characters allow for the separation of individuals into recognisable, homogeneous groups that differ from other such groups in a consistent way. We compared here the suitability and efficacy of traditionally used shell morphology and DNA-based methods to distinguish among species of the freshwater snail genus Radix (Basommatophora, Pulmonata). Results Morphometric analysis showed that shell shape was unsuitable to define homogeneous, recognisable entities, because the variation was continuous. On the other hand, the Molecularly defined Operational Taxonomic Units (MOTU), inferred from mitochondrial COI sequence variation, proved to be congruent with biological species, inferred from geographic distribution patterns, congruence with nuclear markers and crossing experiments. Moreover, it could be shown that the phenotypically plastic shell variation is mostly determined by the environmental conditions experienced. Conclusion Contrary to DNA-taxonomy, shell morphology was not suitable for delimiting and recognising species in Radix. As the situation encountered here seems to be widespread in invertebrates, we propose DNA-taxonomy as a reliable, comparable, and objective means for species identification in biological research.
- Casanovas are liars: behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [v1; ref status: approved with reservations 3, http://f1000r.es/pc] (2013)
- Mate choice in many species is sensitive to social cues from neighboring individuals; for example, animals can copy mate choice decisions. If males copy other males’ choices, sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect), thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR). Using a comparative approach, we tested the hypothesis that SCR is indeed a driving force explaining the occurrence of audience-induced changes in poeciliid male mate choice behavior. If this were true, then males of species with higher overall sexual activity — and, thus, higher potential for multiple mating — should show stronger audience effects. We investigated ten poeciliid species (in two cases including multiple populations) and found support for our hypothesis as mean sexual activity correlated positively with the occurrence of potentially deceptive behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species, and so we also characterized the examined species for aggressiveness using staged contests of size-matched males. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation), but we detected no correlation between aggressiveness and audience effects. Suites of correlated behavioral tendencies are termed behavioral syndromes, and our present study provides correlational evidence for the evolutionary significance of SCR in shaping a behavioral syndrome at the species level across poeciliid taxa.
- Casanovas are liars: behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [v2; ref status: indexed, http://f1000r.es/1ko] (2013)
- Male reproductive biology can by characterized through competition over mates as well as mate choice. Multiple mating and male mate choice copying, especially in internally fertilizing species, set the stage for increased sperm competition, i.e., sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect), thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR). Nevertheless, species might differ consistently in their expression of aggressive and reproductive behaviors, possibly due to varying levels of SCR. In the current study, we present a unique data set comprising ten poeciliid species (in two cases including multiple populations) and ask whether species can be characterized through consistent differences in the expression of aggression, sexual activity and changes in mate choice under increased SCR. We found consistent species-specific differences in aggressive behavior, sexual activity as well as in the level of misleading behavior, while decreased preference expression under increased SCR was a general feature of all but one species examined. Furthermore, mean sexual activity correlated positively with the occurrence of potentially misleading behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation), but did not detect a correlation between aggressiveness and audience effects. Suites of correlated behavioral tendencies are termed behavioral syndromes, and our present study provides correlational evidence for the evolutionary significance of SCR in shaping a behavioral syndrome at the species level across poeciliid taxa.
- Speciation and phylogeography in the cosmopolitan marine moon jelly, Aurelia sp (2002)
- Background: The cosmopolitan moon jelly Aurelia is characterized by high degrees of morphological and ecological plasticity, and subsequently by an unclear taxonomic status. The latter has been revised repeatedly over the last century, dividing the genus Aurelia in as many as 12 or as little as two species. We used molecular data and phenotypic traits to unravel speciation processes and phylogeographic patterns in Aurelia. Results: Mitochondrial and nuclear DNA data (16S and ITS-1/5.8S rDNA) from 66 world-wide sampled specimens reveal star-like tree topologies, unambiguously differentiating 7 (mtDNA) and 8 (ncDNA) genetic entities with sequence divergences ranging from 7.8 to 14% (mtDNA) and 5 to 32% (ncDNA), respectively. Phylogenetic patterns strongly suggest historic speciation events and the reconstruction of at least 7 different species within Aurelia. Both genetic divergences and life history traits showed associations to environmental factors, suggesting ecological differentiation forced by divergent selection. Hybridization and introgression between Aurelia lineages likely occurred due to secondary contacts, which, however, did not disrupt the unambiguousness of genetic separation. Conclusions: Our findings recommend Aurelia as a model system for using the combined power of organismic, ecological, and molecular data to unravel speciation processes in cosmopolitan marine organisms. © 2002 Schroth et al; licensee BioMed Central Ltd. Verbatim copying and redistribution of this article are permitted in any medium for any non-commercial purpose, provided this notice is preserved along with the article's original URL: http://www.biomedcentral.com/1471-2148/2/1
- Introduction: extent, processes and evolutionary impact of interspecific hybridization in animals (2008)
- Since the time of Charles Darwin, studies of interspecific hybridization have been a major focus for evolutionary biologists. Although this phenomenon has often been viewed as problematic in the fields of ecology, taxonomy and systematics, it has become a primary source of data for studies on speciation and adaptation. Effects from genetic/evolutionary processes, such as recombination and natural selection, usually develop over extended periods of time; however, they are accelerated in cases of hybridization. Interspecific hybrids exhibit novel genomes that are exposed to natural selection, thus providing a key to unravel the ultimate causes of adaptation and speciation. Here we provide firstly a historic perspective of hybridization research, secondly a novel attempt to assess the extent of hybridization among animals and thirdly an overview of the reviews and case studies presented in this theme issue.