Institut für Ökologie, Evolution und Diversität
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An updated inventory of the Bromeliaceae for Costa Rica is presented including citations of representative specimens for each species. The family comprises 18 genera and 198 species in Costa Rica, 32 species being endemic to the country. Additional 36 species are endemic to Costa Rica and Panama. Only 4 of the 8 bromeliad subfamilies occur in Costa Rica, with a strong predominance of Tillandsioideae (7 genera/150 spp.; 75.7% of all bromeliad species in Costa Rica). 124 species (62.6%) grow exclusively epiphytic, additional 59 spp. (29.8%) are facultative epiphytes. The most diverse genus is Werauhia, with 59 species (29.8% of the Costa Rican bromeliad flora), followed by Tillandsia with 40 species (20.2%) and Guzmania with 28 spp. (8.6%).
We report new localities for the lizard Anolis salvini Boulenger, 1885, along the Pacific slopes of the Cordillera Central in Chiriquí province and the Comarca Ngöbe-Buglé of western Panama. These records extend the known geographic distribution of this species about 70 km eastwards. They also extend the known vertical distribution approximately 70 m uphill. Additionally, we provide the first record for the Caribbean slopes, an updated distribution map, photos of specimens from different localities, an analysis of a distress call, and comments on the morphology of this species.
We demonstrate how a classical taxonomic description of a new species can be enhanced by applying new generation molecular methods, and novel computing and imaging technologies. A cave-dwelling centipede, Eupolybothrus cavernicolus Komerički & Stoev sp. n. (Chilopoda: Lithobiomorpha: Lithobiidae), found in a remote karst region in Knin, Croatia, is the first eukaryotic species for which, in addition to the traditional morphological description, we provide a fully sequenced transcriptome, a DNA barcode, detailed anatomical X-ray microtomography (micro-CT) scans, and a movie of the living specimen to document important traits of its ex-situ behaviour. By employing micro-CT scanning in a new species for the first time, we create a high-resolution morphological and anatomical dataset that allows virtual reconstructions of the specimen and subsequent interactive manipulation to test the recently introduced ‘cybertype’ notion. In addition, the transcriptome was recorded with a total of 67,785 scaffolds, having an average length of 812 bp and N50 of 1,448 bp (see GigaDB). Subsequent annotation of 22,866 scaffolds was conducted by tracing homologs against current available databases, including Nr, SwissProt and COG. This pilot project illustrates a workflow of producing, storing, publishing and disseminating large data sets associated with a description of a new taxon. All data have been deposited in publicly accessible repositories, such as GigaScience GigaDB, NCBI, BOLD, Morphbank and Morphosource, and the respective open licenses used ensure their accessibility and re-usability.
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
Global climate change is one of the major driving forces for adaptive shifts in migration and breeding phenology and possibly impacts demographic changes if a species fails to adapt sufficiently. In Western Europe, pied flycatchers (Ficedula hypoleuca) have insufficiently adapted their breeding phenology to the ongoing advance of food peaks within their breeding area and consequently suffered local population declines. We address the question whether this population decline led to a loss of genetic variation, using two neutral marker sets (mitochondrial control region and microsatellites), and one potentially selectively non-neutral marker (avian Clock gene). We report temporal changes in genetic diversity in extant populations and biological archives over more than a century, using samples from sites differing in the extent of climate change. Comparing genetic differentiation over this period revealed that only the recent Dutch population, which underwent population declines, showed slightly lower genetic variation than the historic Dutch population. As that loss of variation was only moderate and not observed in all markers, current gene flow across Western and Central European populations might have compensated local loss of variation over the last decades. A comparison of genetic differentiation in neutral loci versus the Clock gene locus provided evidence for stabilizing selection. Furthermore, in all genetic markers, we found a greater genetic differentiation in space than in time. This pattern suggests that local adaptation or historic processes might have a stronger effect on the population structure and genetic variation in the pied flycatcher than recent global climate changes.
A new species of the eutroglobiont gastropod taxon Zospeum Bourguignat, 1856 is described. Zospeum tholussum sp. n. is characterized based on a population from the Lukina Jama–Trojama cave system (Velebit Mts., Croatia). A single living specimen occurred at 980 m depth. The species is morphologically related to Zospeum amoenum (Frauenfeld, 1856), but can be readily distinguished from the latter by the presence of a weak columellar fold and its dome-like structured 2nd whorl. DNA barcoding is capable to clearly delineate Zospeum tholussum from other Zospeum spp. as well.
Molecular phylogenetic studies of Moraea Mill. and the inclusion of Barnardiella Goldblatt, Galaxia Thunb., Gynandriris Parl., Hexaglottis Vent., Homeria Vent. and Roggeveldia Goldblatt in the genus have rendered the existing infrageneric classification, dating from 1976, in need of substantial revision. In particular, subg. Moraea and subg. Vieusseuxia have been shown to be paraphyletic. We propose a new infrageneric classification, based, as far as current data permit, on phylogenetic principles. Monophyletic subgenera and sections are circumscribed based on molecular phylogenies alone or in combination with morphological considerations. We recognize 11 subgenera, 15 sections and three series, arranged as follows in phylogenetic sequence: Plumarieae; Visciramosae (with sect. Multifoliae and sect. Visciramosae); Moraea (with sect. Moraea and sect. Polyphyllae); Galaxia (with ser. Unguiculatae, ser. Eurystigma and ser. Galaxia); Monocephalae; Acaules; Polyanthes (with sect. Serpentinae, sect. Deserticola, sect. Hexaglottis, sect. Gynandriris, sect. Polyanthes and sect. Pseudospicatae); Grandifl orae; Vieusseuxia (with sect. Integres, sect. Vieusseuxia and sect. Villosae); and Homeria (with sect. Stipanthera, sect. Flexuosae, sect. Homeria and sect. Conantherae). Most are moderately to well circumscribed at the morphological level either by floral or vegetative characters, except subg. Moraea, which includes a small number of unspecialized species apparently not linked by any apomorphic features. With over 27 new species described in the past 25 years and another 60 transferred to the genus, Moraea now includes 214 species. We provide a full taxonomic synopsis of the genus.
Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. The characterization of differences between populations in native and invasive ranges may improve our understanding of range expansion and adaptation. Here, we investigated germination characteristics of Ambrosia artemisiifolia L., a successful invader in Europe, under a temperature gradient between 5 and 25 °C. Besides rate and speed of germination we determined optimal, minimal and maximal temperature for germination of ten North American and 17 European populations that were sampled along major latitudinal and longitudinal gradients. We furthermore investigated the frost tolerance of seedlings. Germination rate was highest at 15 °C and germination speed was highest at 25 °C. Germination rate, germination speed, frost tolerance of seedlings, and the temperature niche width for germination were significantly higher and broader, respectively, for European populations. This was partly due to a higher seed mass of these populations. Germination traits lacked evidence for adaptation to climatic variables at the point of origin for both provenances. Instead, in the native range, seedling frost tolerance was positively correlated with the risk of frosts which supports the assumption of local adaptation. The increased frost tolerance of European populations may allow germination earlier in the year which may subsequently lead to higher biomass allocation—due to a longer growing period—and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and enhance the existing public health problems associated with this species.
Long-distance seed dispersal is a crucial process allowing the dispersal of fleshy-fruited tree species among forest fragments. In particular, large frugivorous bird species have a high potential to provide inter-patch and long-distance seed transport, both important for maintaining fundamental genetic and demographic processes of plant populations in isolated forest fragments. In the face of increasing worldwide forest fragmentation, the investigation of long-distance seed dispersal and the factors influencing seed dispersal processes has recently become a central issue in ecology. In my thesis, I studied the movement behaviour and the seed dispersal patterns of the trumpeter hornbill (Bycanistes bucinator), a large obligate frugivorous bird, in KwaZulu-Natal, South Africa. I investigated (i) the potential of trumpeter hornbills to provide long-distance seed dispersal within different landscape structures, (ii) seasonal variations in ranging behaviour of this species, and (iii) the potential of this species to enhance the functional connectivity of a fragmented landscape. I used highresolution GPS-data loggers to record temporally and spatially fine-scaled movement data of trumpeter hornbills within both continuous forests and fragmented agricultural landscapes during the breeding- and the non-breeding season. First, combining these data with data on seed-retention times, I calculated seed dispersal kernels, able to distinguish between seed dispersal kernels from the continuous forests and those from the fragmented agricultural landscapes. The seed dispersal distributions showed a generally high ability of trumpeter hornbills to generate seed transport over a distance of more than 100 m and for potential dispersal distances of up to 14.5 km. Seed dispersal distributions were considerably different between the two landscape types, with a bimodal distribution showing larger dispersal distances for fragmented agricultural landscapes and a unimodal one for continuous forests. My results showed that the landscape structure strongly influenced the movement behaviour of trumpeter hornbills, and this variation in behaviour is likely reflected in the shape of the seed dispersal distributions. Second, for each individual bird I calculated daily ranges and investigated differences in daily ranging behaviour and in the process of range expansion comparatively between the breeding- and the non-breeding season. I considered differences in habitat use and possible consequences resulting for seed dispersal function during different seasons. I found that within the breeding season multi-day ranges were built from strongly overlapping and nearly stationary daily ranges which were almost completely restricted to continuous forest. In the non-breeding season, however, birds assembled multi-day ranges by shifting their range site to a generally different area, frequently utilizing the fragmented agricultural landscape. Thereby, several small daily ranges and few large daily ranges composed larger multi-day ranges within the non-breeding season. Seasonal differences in ranging behaviour and range assembly processes resulted in important consequences for seed dispersal function, with short distances and less spatial variation during the breeding season and more inter-patch dispersal across the fragmented landscape during the non-breeding season. Last, I used a projection of simulated seed dispersal events on a high-resolution habitat map to assess the extent to which trumpeter hornbills potentially facilitate functional connectivity between plant populations of isolated forest fragments. About 7% of dispersal events resulted in potential between-patch dispersal and trumpeter hornbills connected a network of about 100 forest patches with an overall extent of about 50 km. Trumpeter hornbills increased the potential of functional connectivity of the landscape more than twofold and seed dispersal pathways revealed certain forest patches as important stepping-stones for seed dispersal among forest fragments. Overall, my study highlights the overriding role that large frugivorous bird species, like trumpeter hornbills, play in seed dispersal in fragmented landscapes. In addition, it shows the importance of fine-scaled movement data combined with high-resolution habitat data and consideration of different landscape structures and seasonality for a comprehensive understanding of seed dispersal function.
Adaptive Radiation und Zoogeographie anisakider Nematoden verschiedener Klimazonen und Ozeane
(2013)
Anisakide Nematoden sind Parasiten aquatischer Organismen und weltweit in marinen Habitaten verbreitet. Ihre Übertragungswege sind tief im marinen Nahrungsnetz verwurzelt und schließen ein breites Spektrum pelagisch/benthischer Invertebraten (z.B. Cephalopoda, Gastropoda, Crustacea, Polychaeta) und Vertebraten (z.B. Teleostei, Elasmobranchia, Cetacea, Pinnipedia, Aves) als Zwischen- bzw. Endwirte ein. Aufgrund der hohen Befallszahlen u.a. in der Muskulatur und Viszera kommerziell intensiv genutzter Fischarten (z.B. Clupea harengus, Gadus morhua, Salmo salar) sowie ihrer Rolle als Auslöser der menschlichen Anisakiasis nehmen die Vertreter der Gattung Anisakis unter den anisakiden Nematoden eine Sonderstellung ein. Anhand der verbesserten Diagnostik und der Etablierung sowie Weiterentwicklung molekularbiologischer Methoden ist es in den letzten zwei Dekaden gelungen, die bestehende Taxonomie und Systematik der Gattung Anisakis zu erweitern bzw. zu revidieren. Aktuelle molekulare Analysen weisen auf die Existenz von insgesamt neun distinkten Arten hin, welche eine hohe genetische Heterogenität und Wirtsspezifität aufweisen, äußerlich jedoch nahezu identisch sind (sog. kryptische Arten). Trotz kontinuierlicher Forschung auf dem Gebiet ist das Wissen über die Biologie von Anisakis immer noch unzureichend.
Die vorliegende Dissertation ist in kumulativer Form verfasst und umfasst drei (ISI-) Einzelpublikationen. Die Zielsetzung der durchgeführten Studien bestand unter anderem darin, unter Verwendung molekularbiologischer und computergestützter Analyseverfahren, Fragestellungen zur Zoogeographie, (Co-)Phylogenie, Artdiagnostik, Lebenszyklus-Ökologie sowie des bioindikatorischen Potentials dieser Gattung zu bearbeiten und bestehende Wissenslücken zu schließen.
Die Verbreitung von Anisakis, welche bisher ausschließlich anhand von biogeographischen Einzelnachweisen abgeschätzt wurde, konnte durch den angewandten Modellierungsansatz erstmalig interpoliert und in Kartenform vergleichend dargestellt werden. Dabei wurde gezeigt, dass die Verbreitung von Anisakis spp. in den Ozeanen und Klimazonen nicht gleichmäßig ist. Die Analysen deuten auf die Existenz spezies-spezifischer horizontaler und vertikaler Verbreitungsmuster hin, welche neben abiotischen Faktoren durch die Verbreitung und Abundanz der jeweiligen Zwischen- und Endwirte sowie deren Tiefenverteilung und Nahrungspräferenzen geprägt sind.
Durch die umfangreiche Zusammenstellung und anschließende Kategorisierung der (mit molekularen Methoden) geführten Zwischenwirtsnachweise konnten indirekte Rückschlüsse über die vertikale Verbreitung von Anisakis spp. entlang der Tiefenhabitate gezogen werden.
Während Anisakis auf Gattungsebene in der gesamten Wassersäule entlang verschiedener Tiefenhabitate abundant ist, wurde für die stenoxene Art Anisakis paggiae ein meso-/bathypelagisch orientierter Lebenszyklus postuliert. Durch den Einbezug eines breiten Spektrums (paratenischer) Zwischen- und Transportwirte aus unterschiedlichen trophischen Ebenen werden Transmissionslücken im Lebenszyklus der Gattung weitestgehend minimiert und der Transmissionserfolg auf den Endwirt, und damit die Wahrscheinlichkeit einer erfolgreichen Reproduktion, erhöht. Ausgeprägte Wirtspräferenzen sowie phylogenetische Analysen des ribosomalen ITS-Markers stützen eine Theorie zur co-evolutiven Anpassung der Parasiten an ihre Endwirte. Anisakis eignet sich daher unter Einschränkungen als Bioindikator für die vertikale und horizontale Verbreitung und Abundanz der Endwirte und lässt Rückschlüsse auf trophische Interaktionen im Nahrungsnetz zu. Durch die weitere Beprobung von Zwischenwirten aus verschiedenen trophischen Ebenen in zukünftigen Studien, kann eine genauere Bewertung potentiell abweichender Lebenszyklus-Strategien gewährleistet werden. Insbesondere ist die Datenlage zur Prävalenz und Abundanz anisakider Nematoden in Cephalopoda und Crustacea noch unzureichend. Die Probennahme sollte dabei unter besonderer Berücksichtigung bislang wenig oder unbeprobter geographischer Regionen, Tiefenhabitate und Wirtsarten durchgeführt werden.