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Linking bird diversity and agricultural management in tropical farmlands

Agricultural intensification, characterized by the loss of native flora and the establishment of monocultures, has been negatively associated with the richness of bird species in tropical regions. However, very little is known about the impact on avian functional roles and evolutionary history across gradients of intensification. In this paper, KLIVV and University of Vienna scientists analyzed the response of the taxonomic, functional and phylogenetic dimensions of bird diversity inside coffee farms with different management practices.

By conducting fieldwork across a ~2000m elevational gradient, they also evaluated the effect of elevation on the response of the bird communities to intensification. They found that the response of the diversity dimensions was linked to specific vegetation elements within the farms, but also to the elevation zone being considered. 

The article "Taxonomic, functional and phylogenetic bird diversity response to coffee farming intensity along an elevational gradient in Costa Rica" by Otto Monge, Stefan Dullinger, Leonida Fusani, and Christian H. Schulz was recently published in the journal Agriculture, Ecosystems & Environment.


"Mini-Mallnitz" KLIVV/FIWI online scientific exchange

A side-effect of working from home during the Covid-19 pandemic has been a loss of contact with our colleagues. As well as being an important part of our social lives, those brief chats over coffee or while passing in the corridor were helpful to keep us connected regarding our current scientific work and the associated successes and challenges that we experience. To make up for this lack of casual, science-related communication, this year (2021) we decided to start an online event that would allow as many Wilhelminenberg scientists and students as possible to meet up for some scientific exchange.

On 30th November, over 50 scientists and students from FIWI and KLIVV (including the Wolf Science Centre) met online in the second edition of the meeting. You can see some of the participants in the screenshot above. We’re happy to report that it was a great success once more!

Our current format involves five to six very short talks in three sessions lasting an hour each over the course of half a day. The content includes ongoing research projects, as well as insights into the scientific services offered at Wilhelminenberg. We try to give priority to talks from our student colleagues at PhD and Masters levels, and see the meeting as an excellent opportunity for all of us to practice giving talks in a friendly environment. The strict maximum time limit of 5 minutes per speaker allows an efficient overview of many projects but it can be challenging for the presenters. So far it has worked really well – we haven’t had to mute anybody yet!

We would like to continue holding the meeting twice a year either fully online or in a hybrid format, preferably with a rotating organizing committee. In case you’re interested in helping to plan the next meeting, please get in touch.


Pheromones that influence male reproductive success

Many studies have identified compounds, often called 'pheromones', which influence sexual behavior and physiology in laboratory mice under laboratory conditions. It is widely assumed that these compounds influence reproductive success, and yet surprisingly, this assumption has never been tested in mice or any other mammal. To investigate this hypothesis, a study was recently conducted by Dustin Penn and Sarah Zala and their students at the Konrad Lorenz Institute of Ethology, and their collaborator, Jae Kwak, a chemist who has special technical expertise with pheromones.

They aimed to test whether the pheromones previously identified in studies on laboratory mice actually influence the reproductive success of wild house mice. They released wild house mice into large enclosures where they competed for territories and mates. For 16 weeks, they observed the behavior of the mice, collected urine samples and measured the output of non-volatile and volatile pheromones, and then determined reproductive success using genetic paternity analyses of the offspring.

They found that urinary protein excretion was correlated with male but not female reproductive success. This result explains why male mice produce 3 to 4 times more urinary protein than females. To their surprise, only one volatile pheromone was positively correlated with the number of offspring sired by males. Another compound, trimethylamine or TMA, was negatively correlated with male reproductive success. According to Dr. Penn, TMA smells like rotten fish or dead and decaying animals to the human nose, and it is used an indicator of spoilage. He explains that other studies have found that mice are attracted to normal levels of TMA in the urine, but they are aversive to high concentrations. Interestingly TMA has been found to be elevated in the urine of infected mice. The lead author on the paper, Ken Luzynski, who recently defended his dissertation at the Vetmed Uni, points out that several of their findings are novel, and although they are correlative, some are consistent with results of experimental studies.

The article "Pheromones that correlate with reproductive success in competition conditions" by Kenneth C. Luzynski, Doris Nicolakis, Maria Adelaide Marconi, Sarah M. Zala, Jae Kwak, and Dustin J. Penn was published in Scientific Reports.


Siblings matter: Family heterogeneity and learning in fish

Despite the strong interest in connecting social complexity and cognitive ability, there remains considerable debate about how to best quantify both cognitive performance and social complexity.

For this study, researchers from the Konrad Lorenz Institute of Ethology used two species of cichlid fishes from Lake Tanganyika, one cooperative breeder and one biparental species, in a cross-fostering experiment, to investigate the links between social complexity and cognition. While controlling for parental cues, individual fish grew up either in a socially homogenous group with only conspecifics or in a mixed and diverse social group with hetero- as well as conspecifics and then were tested for learning abilities as subadults.

To quantify differences in learning, the scientists first employed a discrimination learning task followed by a reversal learning task that requires behavioral flexibility, as previous associations are forgotten and new associations forged. They found that individuals growing up in a more diverse social environment learned faster and made fewer mistakes in the discrimination learning task, but this ability did not transfer to the reversal learning task. Irrespective of the early social experiences, the cooperatively breeding, and thus the more social of the two cichlid species, learned the colour discrimination more quickly and made significantly fewer errors.

These results provide a first demonstration of a possible association between cognitive performance and social complexity in cichlid fishes.

The article "Siblings matter: Family heterogeneity improves associative learning later in life" by Stefan Fischer, Sigal Balshine, Michaela C. Hadolt, and Franziska C. Schaedelin was published in September in the journal Ethology.



Old trees are good for the Ural owl

For 20 years the Ural owl population has been growing again in Austria. This large, charismatic species of owl was declared extinct across the country in the middle of the 20th century due to habitat loss and killings. There are currently around 45 breeding pairs in the wild again, around a third of them in Vienna. This positive development is the result of one of Dr. Richard Zink´s projects, a resettlement project that he initiated in 2009, which is extremely successful. Since the start of the project, 460 young birds have been released from breeding facilities such as the zoo. The project is accompanied by a continuous monitoring programme. The genetic "fingerprint" of each animal is also stored in a database. In this way, individual birds can be observed in the wild and their breeding success documented. Webcams provide insight into nesting boxes, and foot rings with transmitters enable the animals' movements to be tracked. Some of them fly as far as the Czech-Bavarian border or to Slovenia, where they can connect to the existing Ural owl populations. This mixing is important in order to increase the genetic diversity and thus the resilience of the Austrian population.

The owls are doing particularly well in Vienna. In the Lainzer Tiergarten, where there are a lot of old trees, the Ural owl finds ideal breeding conditions, because the owls like to nest in tree hollows. But also in other areas, where the forest is managed less naturally, the animals are getting new breeding opportunities. Richard Zink and his team have been installing nesting aids in the Vienna Woods since 2011 (ideal are disused urban rubbish bins that are mounted high on trees).

More information about the project is available on the Ural Owl website.



The Reproductive Advantages of Large Male Fish

In mosquitofish, of the genus Gambusia, male fish are smaller than females – sometimes only half the size. Biologists had previously assumed that smaller male mosquitofish had at least some reproductive advantages. Researchers from the transregional collaborative research centre NC3 at Bielefeld University, among them Bora Kim who is now doing research work at the Konrad Lorenz Institute of Ethology, have shown in a systematic review and meta-analysis that larger mosquitofish are actually more successful at reproduction: they can, for instance, better challenge their rivals; they produce more sperm; and they are preferred by female fish.

The article "Male size and reproductive performance in three species of livebearing fishes (Gambusia spp.): a systematic review and meta-analy-sis" by Bora Kim, Nicholas Patrick Moran, Klaus Reinhold, Alfredo Sánchez-Tójar was published in July in the Journal of Animal Ecology.