Breeding status affects the expression of androgen and progesterone receptor mRNA in the brain of male Damaraland mole-rats

The eusocial Damaraland mole-rat (Fukomys damarensis) represents an extreme example of reproductive skew, in that reproduction is completely blocked in female subordinate group members. Similarly, male subordinates within the colony show no sexual behaviour. In contrast to females, however, non-reproductive males have functional gonads and do not differ in circulating levels of pituitary hormones and testosterone from reproductive males. Nevertheless, they have reduced numbers of follicle-stimulating hormone receptors in their testes and they produce fewer spermatozoa with a large proportion of immature spermatozoa and precursors. To understand the mechanism of reproductive suppression operational in subordinate males we studied the expression of androgen and progesterone receptor genes in forebrain regions involved in the control of reproductive behaviour in male breeders and nonbreeders from intact colonies. While it is well documented that testosterone activates maletypical behaviour, the role of progesterone in this process is less clear as previous studies have produced contradictory results. We found expression of androgen receptor (AR) and progesterone receptor (PGR) genes in several forebrain regions of male Damaraland molerats. The distribution of AR in males matches our previous findings in females. This is the first report showing the distribution of PGR in mole-rats. We found PGR in all areas which were also sensitive to androgens and estrogens. Analysis of the optical densities of the AR and PGR hybridisation signal revealed that breeding males had increased expression of AR and PGR compared to non-breeders in most brain regions examined, which include the medial preoptic area, the bed nucleus of the stria terminalis, the ventromedial nucleus of the hypothalamus, the arcuate nucleus and the medial amygdala. These status-related differences were more pronounced for PGR than for AR. This study shows that breeding position affects the neuroendocrine phenotype of male Damaraland mole-rats. Further, it suggests that androgens and progesterone might act synergistically in activating sexual behaviour in males.A fellowship from the University of Pretoria to CV and funding from the DST-NRF to NB.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-79982017-03-31hb2016Mammal Research InstituteZoology and Entomolog

Hatching late in the season requires flexibility in the timing of song learning

Most songbirds learn their songs from adult tutors, who can be their father or other male conspecifics. However, the variables that control song learning in a natural social context are largely unknown. We investigated whether the time of hatching of male domesticated canaries has an impact on their song development and on the neuroendocrine parameters of the song control system. Average age difference between early- and late-hatched males was 50 days with a maximum of 90 days. Song activity of adult tutor males decreased significantly during the breeding season. While early-hatched males were exposed to tutor songs for on average the first 99 days, late-hatched peers heard adult song only during the first 48 days of life. Remarkably, although hatching late in the season negatively affected body condition, no differences between both groups of males were found in song characteristics either in autumn or in the following spring. Similarly, hatching date had no effect on song nucleus size and circulating testosterone levels. Our data suggest that late-hatched males must have undergone accelerated song development. Furthermore, the limited tutor song exposure did not affect adult song organization and song performance.http://rsbl.royalsocietypublishing2016-08-30hb2016Zoology and Entomolog

Duets recorded in the wild reveal that interindividually coordinated motor control enables cooperative behavior

Many organisms coordinate rhythmic motor actions with those of a partner to generate cooperative social behavior such as duet singing. The neural mechanisms that enable rhythmic interindividual coordination of motor actions are unknown. Here we investigate the neural basis of vocal duetting behavior by using an approach that enables simultaneous recordings of individual vocalizations and multiunit vocal premotor activity in songbird pairs ranging freely in their natural habitat. We find that in the duet-initiating bird, the onset of the partner's contribution to the duet triggers a change in rhythm in the periodic neural discharges that are exclusively locked to the initiating bird's own vocalizations. The resulting interindividually synchronized neural activity pattern elicits vocalizations that perfectly alternate between partners in the ongoing song. We suggest that rhythmic cooperative behavior requires exact interindividual coordination of premotor neural activity, which might be achieved by integration of sensory information originating from the interacting partner

Breeding status and social environment differentially affect the expression of sex steroid receptor and aromatase mRNA in the brain of female Damaraland mole-rats

INTRODUCTION: The Damaraland mole-rat (Fukomys damarensis) is a eusocial, subterranean mammal, which exhibits an extreme reproductive skew with a single female (queen) monopolizing reproduction in each colony. Non-reproductive females in the presence of the queen are physiologically suppressed to the extent that they are anovulatory. This blockade is thought to be caused by a disruption in the normal gonadotropin-releasing hormone (GnRH) secretion from the hypothalamus. In order to understand the underlying physiological mechanisms of reproductive suppression in subordinate females we studied the expression of steroid hormone receptors and the androgen-converting enzyme aromatase in forebrain regions involved in the control of reproductive behaviour in female breeders and non-breeders from intact colonies. Additionally, we included in our analysis females that experienced the release from social suppression by being removed from the presence of the queen. RESULTS: We found expression of androgen receptor, estrogen receptor α and aromatase in several forebrain regions of female Damaraland mole-rats. Their distribution matches previous findings in other mammals. Quantification of the hybridisation signal revealed that queens had increased expression of androgen receptors compared to non-breeders and removed non-breeders in most brain regions examined, which include the medial preoptic area (MPOA), the principal nucleus of the bed nucleus of the stria terminalis (BSTp), the ventromedial nucleus of the hypothalamus (VMH), the arcuate nucleus (ARC) and the medial amygdala (MeA). Furthermore, breeders had increased estrogen receptor α expression in the anteroventral periventricular nucleus (AVPV) and in the MeA, while aromatase expression in the AVPV was significantly reduced compared to non-breeders. Absence of social suppression was associated with increased androgen receptor expression in the ARC, increased estrogen receptor α expression in the MeA and BSTp and reduced aromatase expression in the AVPV. CONCLUSION: This study shows that social suppression and breeding differentially affect the neuroendocrine phenotype of female Damaraland mole-rats. The differential expression pattern of estrogen receptor α and aromatase in the AVPV between breeders and non-breeders supports the view that this region plays an important role in mediating the physiological suppression in subordinate females.Fellowships from the University of Pretoria to CV and HL as well as the DST-NRF for funding to NB.http://www.frontiersinzoology.com/am201

Social Status Affects the Degree of Sex Difference in the Songbird Brain

It is thought that neural sex differences are functionally related to sex differences in the behaviour of vertebrates. A prominent example is the song control system of songbirds. Inter-specific comparisons have led to the hypothesis that sex differences in song nuclei size correlate with sex differences in song behaviour. However, only few species with similar song behaviour in both sexes have been investigated and not all data fit the hypothesis. We investigated the proposed structure – function relationship in a cooperatively breeding and duetting songbird, the white-browed sparrow weaver (Plocepasser mahali). This species lives in groups of 2–10 individuals, with a dominant breeding pair and male and female subordinates. While all male and female group members sing duet and chorus song, a male, once it has reached the dominant position in the group, sings an additional type of song that comprises a distinct and large syllable repertoire. Here we show for both types of male – female comparisons a male-biased sex difference in neuroanatomy of areas of the song production pathway (HVC and RA) that does not correlate with the observed polymorphism in song behaviour. In contrast, in situ hybridisation of mRNA of selected genes expressed in the song nucleus HVC reveals a gene expression pattern that is either similar between sexes in female – subordinate male comparisons or female-biased in female – dominant male comparisons. Thus, the polymorphic gene expression pattern would fit the sex- and status-related song behaviour. However, this implies that once a male has become dominant it produces the duetting song with a different neural phenotype than subordinate males

Regionale Standards: Ausgabe 2013

"Die 'Regionalen Standards' gehen zurück auf die Initiative eines gemeinsamen Arbeitskreises, bestehend aus Vertretern des Statistischen Bundesamtes, der Arbeitsgemeinschaft Sozialwissenschaftlicher Institute e.V. (ASI) und des ADM Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V. Sie stellen ein Angebot für die Forschung in der Bundesrepublik Deutschland dar. Die 'Regionalen Standards' beschreiben Gebietsabgrenzungen und Instrumente zur Typisierung von Regionen, wie sie in der Bundesrepublik Deutschland von der amtlichen Statistik und/oder der Markt- und Sozialforschung in gewisser Regelmäßigkeit eingesetzt werden. Zusätzlich werden Datensätze aus unterschiedlichen Quellen vorgestellt, die für die Regionalisierung von Bevölkerungsumfragen genutzt werden können und für die Forschung (teils jedoch mit Einschränkungen) zur Verfügung stehen. Ergänzt werden die 'Regionalen Standards' durch eine jährlich aktualisierte Tabellenanalyse aus dem Mikrozensus, zu beziehen über die Internetseiten www.destatis.de, www.gesis.org und www.adm-ev.de." (Autorenreferat

Fifth European Dirofilaria and Angiostrongylus Days (FiEDAD) 2016

Peer reviewe

Kompetenzerwerb in der Schule : Evaluation der Klassenprojekte im Rahmen von "Ich & Du". Hand in Hand durch das Schuljahr"

Cornelia LeitnerAbstract in englischer SpracheAlpen Adria Universität Klagenfurt, Masterarbeit, 2015(VLID)241162