Chemical analysis reveals sex differences in the preen gland secretion of breeding Blue Tits

Caspers B, Marfull R, Dannenhaus T, Komdeur J, Korsten P. Chemical analysis reveals sex differences in the preen gland secretion of breeding Blue Tits. Journal of Ornithology. 2021;163(1):191–198.**Abstract** Acoustic and visual signals are well known to play important roles in social communication in birds. Growing evidence suggests that many bird species, including species of songbirds, additionally have a well-developed sense of smell. However, we are still at the beginning of understanding the potential importance of chemical communication in the social lives of birds, for example in mate choice. The secretion of the preen gland may be an important contributor to the chemical phenotype of birds. Here, we report on a first characterisation of the chemical composition of the preen gland secretion of the Blue Tit (Cyanistes caeruleus), a common songbird which is an often used model species in animal behaviour and ecology, in particular also in studies of sexual selection and (extra-pair) mate choice. We found sex differences in the composition of the preen gland secretion in breeding Blue Tits. Females further tended to have a larger number of putative compounds in their secretions compared to males. We briefly discuss the possible implications of these findings and speculate that the chemical composition of the preen gland secretion may be a sexually selected trait in Blue Tits. Our preliminary findings warrant follow-up research into the patterns of within- and among individual variation in the chemical composition of the preen gland secretion as well as the identification of the main chemical compounds involved.**Zusammenfassung**Chemische Analyse zeigt Geschlechtsunterschiede im Bürzeldrüsensekret brütender BlaumeisenSingvögel sind vor allem für ihren Gesang und ihre Gefiedermerkmale, die bei der sozialen Kommunikation eine bedeutende Rolle spielen, bekannt. Immer mehr Hinweise deuten aber darauf hin, dass viele Vogelarten, darunter auch Singvogelarten, zusätzlich einen gut entwickelten Geruchssinn haben. Welche Bedeutung die geruchliche Kommunikation im sozialen Leben der Vögel, zum Beispiel bei der Partnerwahl, spielt ist allerdings weitgehend noch unbekannt. Das Bürzeldrüsensekret könnte in diesem Zusammenhang einen wichtigen Beitrag zum chemischen Phänotyp der Vögel leisten. In unserer Studie haben wir uns die chemische Zusammensetzung des Bürzeldrüsensekrets der Blaumeise (Cyanistes caeruleus) in der Brutzeit angeschaut. Blaumeisen sind eine viel genutzte Modellart in der Verhaltensforschung und Verhaltensökologie, insbesondere auch in Studien zur sexuellen Selektion und (außerpaarigen) Partnerwahl. Anhand von chemischen Analysen mittels Gas-Chromatographie fanden wir heraus, dass es bei brütenden Blaumeisen einen Geschlechtsunterschied in der Zusammensetzung des Bürzeldrüsensekrets gibt. Weibchen neigen außerdem dazu, eine größere Anzahl von vermeintlichen Substanzen in ihren Sekreten zu haben als Männchen. Wir diskutieren hier kurz die möglichen Implikationen dieser Ergebnisse und spekulieren, dass die chemische Zusammensetzung des Bürzeldrüsensekrets ein sexuell selektiertes Merkmal bei Blaumeisen sein könnte. Unsere vorläufigen Ergebnisse rechtfertigen Folgeuntersuchungen, in denen die Identifikation der wichtigsten chemischen Verbindungen des Bürzeldrüsensekrets und die Variation innerhalb und zwischen Individuen in der chemischen Zusammensetzung des Drüsensekrets im Fokus stehen

An apparatus and method for detecting a tool

The apparatus is adapted to detect a tool based on a 3D image obtained by a 3D ultrasound imaging system. The apparatus comprises an image processing unit, which includes a tool detection module configured to perform a tool detection procedure. The tool detection procedure involves identifying a shadow of the tool in the 3D image and calculating the position of a "tool plane section" of the 3D image in which the entire length of the tool is represented

Penicillium air mycoflora in postharvest fruit handling environments associated with the pear export chain

Penicillium is a well-known airborne fungal contaminant that is prevalent in indoor air. In this study, the total air mycoflora was determined in postharvest fruit handling environments. The study included eleven indoor environments from the packhouse to the final retail outlet. Standard active and passive air sampling methods were used over a period of three years to obtain a profile of air quality. A total of 6047 and 5849 Penicillium colonies were counted of which 1123 and 508 isolates were obtained using active and passive sampling methods respectively. Ultimately, 25 dominant Penicillium spp. were identified from active air samples. The five most prevalent species isolated were: P. glabrum (31.88%); P. expansum (14.18%); P. crustosum (13.42%); P. chrysogenum (10.35%) and P. brevicompactum (10.25%). Furthermore, a total of 22 Penicililum spp. were isolated from passive air samples with P. glabrum (23.72%); P. italicum (16.45%); P. brevicompactum (14.22%); P. crustosum (13.80%) and P. chrysogenum (11.76%) being most prevalent. The presence of pathogenic Penicillium spp. in the air of fruit handling environments was profiled. Counts of total air mycoflora were significantly higher in the re-pack facilities than in all other environments sampled and are significantly higher than the proposed baseline threshold value. This study clearly shows the importance of air quality in facilities that regularly handle different fruit types. Re-pack and retail facilities should therefore be cleaned more effectively to reduce the potential air inoculum that can induce decay of fruit at the market-end. Finally we propose an air quality standard for fresh produce environments.The National Research Foundation (NRF), Technology and Human Resources for Industry Programme, the South African Apple and Pear Producers Association (administered by Fruitgro Science), the Department of Science and Technology, Fresh Produce Exporters Forum, Postharvest Innovation Programme PHi and the University of Pretoria.http://www.elsevier.com/locate/postharvbio2018-06-01hj2018Plant Production and Soil Scienc