Breeding colony of Common Swifts (Apus apus) in a motorway bridge

Wir beschreiben eine ungewöhnliche Brutkolonie des Mauerseglers unter einer Autobahnbrücke. Im Jahr 2007 bestand die Kolonie aus 38 Brutpaaren, von denen 35 erfolgreich brüteten. Trotzdem war die Überlebensrate der Nestlinge wegen der schlechten Wetterbedingungen sehr niedrig. Nur 7 von 75 Nestlingen flogen aus. Der Standort bietet exzellente Möglichkeiten, weitere Aspekte der Life-History von Mauerseglern zu untersuchen.We describe an unusual site for a nesting colony of the Common Swift situated under a motorway bridge. This colony contained 38 breeding pairs in 2007, 35 of which successfully produced nestlings. However, due to poor weather conditions the survival rate of nestlings was low. Only 7 from a total of 75 nestlings fledged successfully. This site offers an excellent opportunity to study swifts further and to investigate aspects of swift and avian life-history

Habitatwahl von Mauerasseln und Kellerasseln: Wissenschaftliche Arbeitsweisen an einem konkreten Beipsiel vermitteln

Die eigenständige Planung, Durchführung, Auswertung und Interpretation eines Experimentes eignet sich besonders gut für Lernende die Vorgehensweise des wissenschaftlichen Arbeitens zu erproben und zu verstehen. Mit diesem Artikel möchten wir den Lehrkräften mit Hilfe eines einfachen Experimentes alle Schritte des wissenschaftlichen Arbeitens aufzeigen und ihnen Material für den Unterricht (auch als Online-Videomaterial) zur Verfügung stellen

De novo implantation vs. upgrade cardiac resynchronization therapy: a systematic review and meta-analysis

Patients with conventional pacemakers or implanted defibrillators are often considered for cardiac resynchronization therapy (CRT). Our aim was to summarize the available evidences regarding the clinical benefits of upgrade procedures. A systematic literature search was performed from studies published between 2006 and 2017 in order to compare the outcome of CRT upgrade vs. de novo implantations. Outcome data on all-cause mortality, heart failure events, New York Heart Association (NYHA) Class, QRS narrowing and echocardiographic parameters were analysed. A total of 16 reports were analysed comprising 489,568 CRT recipients, of whom 468,205 patients underwent de novo and 21,363 upgrade procedures. All-cause mortality was similar after CRT upgrade compared to de novo implantations (RR 1.19, 95% CI 0.88-1.60, p = 0.27). The risk of heart failure was also similar in both groups (RR 0.96, 95% CI 0.70-1.32, p = 0.81). There was no significant difference in clinical response after CRT upgrade compared to de novo implantations in terms of improvement in left ventricular ejection fraction (DeltaEF de novo - 6.85% vs. upgrade - 9.35%; p = 0.235), NYHA class (DeltaNYHA de novo - 0.74 vs. upgrade - 0.70; p = 0.737) and QRS narrowing (DeltaQRS de novo - 9.6 ms vs. upgrade - 29.5 ms; p = 0.485). Our systematic review and meta-analysis of currently available studies reports that CRT upgrade is associated with similar risk for all-cause mortality compared to de novo resynchronization therapy. Benefits on reverse remodelling and functional capacity improved similarly in both groups suggesting that CRT upgrade may be safely and effectively offered in routine practice. CLINICAL TRIAL REGISTRATION: Prospero Database-CRD42016043747

No “carry-over” effects of tracking devices on return rate and parameters determining reproductive success in once and repeatedly tagged common swifts (Apus apus), a long-distance migratory bird

Finanziert im Rahmen der DEAL-Verträge durch die Universitätsbibliothek SiegenBackground: To understand life-history strategies in migratory bird species, we should focus on migration behaviour and possible carry-over effects on both population and individual level. Tracking devices are useful tools to directly investigate migration behaviour. With increased use of tracking devices, questions arise towards animal welfare and possible negative effects of logger on birds. Several studies were conducted to address this question in birds that were tagged and tracked for one complete non-breeding season including migration but with mixed results. To detect individual-based decisions regarding migration strategy, we need to track the same individuals several times. So far, there are no studies investigating effects of repeatedly tagging on reproduction and life-history traits in individual migratory birds, especially in small birds. Methods: We used long-term data of 85 tagged common swifts (Apus apus), a long-distance migratory bird, of a breeding colony in Germany to test whether carrying a geolocator or GPS logger once or repeatedly during nonbreeding season affected return rate, apparent survival, and parameters determining reproductive success. Additionally, we checked for individual differences in arrival date and breeding parameters when the same individuals were tagged and when they were not tagged in different years. Further, we calculated the individual repeatability in arrival at the breeding colony and date of egg laying in repeatedly tagged swifts. Results: Once and repeatedly tagged birds returned to the colony at a similar rate as non-logger birds and arrived earlier than non-logger birds. We found no effect of logger-type on return rate in logger birds. We detected no differences in apparent survival, time lag to clutch initiation, date of clutch initiation, clutch size, number of chicks and fledglings between logger and non-logger birds. We found neither an effect of loggers nor of logger-types on the arrival date and breeding parameter on individual-level. Arrival date was highly repeatable and date of clutch initiation was moderately repeatable within repeatedly tagged individuals

Sexual imprinting on a novel blue ornament in zebra finches

Witte K, Caspers B. Sexual imprinting on a novel blue ornament in zebra finches. BEHAVIOUR. 2006;143(8):969-991.Sexual imprinting plays an important role for the development of mate preferences in birds. We tested whether male and female zebra finches Taeniopygia guttata sexually imprinted on an evolutionary novel trait, a blue feather on the forehead in parents. Additionally, we tested whether males and females would transfer a learned preference for the blue feather to a preference for blue leg bands, and whether a potential mate with two novel blue traits can amplify its attractiveness. Offspring were raised by parents in four different imprinting groups: (1) both parents unadorned; (2) the mother adorned only; (3) the father adorned only; (4) both parents adorned with the blue feather. After young reached maturity, we tested their mate preference for adorned and unadorned conspecifics of the opposite sex in binary choice tests. Females of the father adorned imprinting group sexually imprinted on the blue feather, and females reared by adorned parents showed a tendency to prefer adorned males. None of the males sexually imprinted on the blue feather. Our study replicates the results of a previous study on sexual imprinting on a red feather in zebra finches. We, therefore, propose a sex difference in the learning process of sexual imprinting. Females sexually imprinted on the blue feather did not transfer the learned preference to males with blue leg bands, and two novel blue traits could not amplify the attractiveness in males and females for the opposite sex. Our study emphasizes the role of sexual imprinting for the cultural evolution in mate preferences in zebra finches

Public information influences sperm transfer to females in sailfin molly males.

In animals, including humans, the social environment can serve as a public information network in which individuals can gather public information about the quality of potential mates by observing conspecifics during sexual interactions. The observing individual itself is also a part of this information network. When recognized by the observed conspecifics as an audience, his/her presence could influence the sexual interaction between those individuals, because the observer might be considered as a potential mate or competitor. One of the most challenging questions in sexual selection to date is how the use of public information in the context of mate choice is linked to the fitness of individuals. Here, we could show that public information influences mate-choice behaviour in sailfin molly males, Poecilia latipinna, and influences the amount of sperm males transfer to a female partner. In the presence of an audience male, males spent less time with the previously preferred, larger of two females and significantly more time with the previously non-preferred, smaller female. When males could physically interact with a female and were faced with an audience male, three audience females or no audience, males transferred significantly more sperm to a female partner in the presence of an audience male than with female audience or no audience and spent less time courting his female partner. This is the first study showing that public information use turns into fitness investment, which is the crucial factor to understand the role of public information in the dynamic processes in sexual selection

Spiralen in der Natur - Anregung zur räumlichen und mathematischen Auseinandersetzung mit Spiralen

Wegner C, Michler K, Witte K. Spiralen in der Natur - Anregung zur räumlichen und mathematischen Auseinandersetzung mit Spiralen. Schulmagazin 5-10. 2016;1(2016):25-31

Phyllotaxis - Die Blattanordnung bei Pflanzen folgt mathematischen Regelmäßigkeiten. Hier zeigt sich die Theorie des goldenen Schnitts an natürlichen Beispielen

Wegner C, Michler K, Witte K. Phyllotaxis - Die Blattanordnung bei Pflanzen folgt mathematischen Regelmäßigkeiten. Hier zeigt sich die Theorie des goldenen Schnitts an natürlichen Beispielen. Praxis der Naturwissenschaften. Biologie in der Schule. 2015;64(6):45-49

It’s in the eye of the beholder: visual lateralisation in response to the social environment in poeciliids

The social environment offers fish complex information about the quality, performance, personality and other cues of potential mates and competitors simultaneously. It is likely, therefore, that the environmental information regarding the context of mate choice is perceived and processed differently in species and sexes in respect to lateralisation. The present study comparatively assessed visual lateralisation behaviour in response to different social or sexual stimuli in three closely related poeciliid species (P. latipinna, P. mexicana, P. formosa ) in comparison to a more distantly related species (P. reticulata ). Individuals were presented with four different social or sexual stimuli that were tested against a control stimulus; (a) a conspecific male, (b) a conspecific female, (c) a heterosexual conspecific pair, (d) three conspecific females (shoal). In order to approach a target stimulus, focal fish had to perform detours to the right or left of a vertically straight‐shaped barrier. The three closely related poeciliid species, P. latipinna , P. mexicana , P. formosa , appeared to have a general tendency to turn right (i.e ., left‐eye preference), whereas the more distantly related P. reticulata males and females showed an overall bias to the left (i.e ., right‐eye preference) in response to various social–sexual incitements. Moreover, body size seemed to significantly influence especially the males’ detour behaviour, with smaller males acting in opposition to their larger conspecifics in response to certain social stimuli. In this case, smaller and larger Poecilia spp. males responded in the same way as smaller and larger males of the other three poeciliid species. Therefore, results possibly point to differences in the degree of general social behaviour between closely and more distantly related species and mating motivation amongst larger and smaller individuals when placed in a novel social environment. Hence, present results possibly suggest a sex‐specific functional lateralisation for the analysis of visual information and seem to support the closer ancestral relationships between the Poecilia spp. tested in this study and the more distantly related guppies in terms of their left–right lateralisation. Generally, present results suggest that functional asymmetries in behaviour could be widespread among vertebrates, thus supporting the hypothesis of an early evolution of lateralisation in brain and behaviour