The behavioural function of pheromones in crayfish

Pacifastacus leniusculus and Procambarus clarkii are highly invasive freshwater crayfish and are having detrimental impacts on native species and habitats throughout Europe. The application of pheromone baits have been proposed as a way of increasing trap efficiency for population control, however the chemical identity of crayfish pheromones is unknown. An incomplete understanding of chemical communication has delayed progress in the development of appropriate bioassays. This thesis therefore focused on researching the natural context of chemical signalling by crayfish, including signal delivery and receiver response.Urine release by male and female crayfish was found to coincide with aggressive behaviours rather than reproductive behaviours. Female urine release was essential for initiating mating, with males detecting female receptivity by spying on hormones and metabolites released with threat signals. Physiological indicators of reception included a brief cardiac and ventilatory arrest followed by an increase in rate. Both behavioural and physiological responses formed the basis of a novel assay design.During courtship male crayfish do not appear to advertise by urine signals. This raised the question of whether chemical signals were important for female assessment of the quality of size-matched males. When given a free choice, females could not distinguish dominant and subordinate males through chemical signals alone. This suggests that females either use other criteria (e.g. size) for mate choice or perform cryptic postcopulatory mate choice.Blocking natural urine release of crayfish, which had previously fought to establish dominance, and artificially introducing urinary signals proved an effective bioassay for investigating the mechanisms of dominance hierarchy formation. Urine from the dominant male was the key factor in establishing dominance relationships. In the absence of dominant urine, subordinate males were less likely to retreat from aggressive bouts and fights were more intense.The mechanisms of signal delivery during agonistic encounters were investigated by measuring ventilatory activity. Increased ventilation rate was associated with highly aggressive behaviours and urinary signalling. This indicated crayfish create gill currents to disperse signals and increase transfer efficiency from sender to receiver.This thesis sheds light into the mechanism of chemical communication in crayfish and provides the basis for future bioassay guided purification of crayfish pheromones

The 31st Aerospace Mechanisms Symposium

The proceedings of the 31st Aerospace Mechanisms Symposium are reported. Topics covered include: robotics, deployment mechanisms, bearings, actuators, scanners, boom and antenna release, and test equipment. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms

An advanced study of an Application Technology Satellite /ATS-4/ mission, volume I, book 2 Final study report, May - Nov. 1966

Application Technology Satellite /ATS/ SPACECRAFT tradeoff and analysis - configuration paraboloid antenna, guidance and control power, spacecraft design, and apogee motor selectio

Surveyor lunar roving vehicle, phase I. Volume III - Preliminary design and system description. Book 2 - Validation of preliminary design, sections 7-13 Final technical report

Systems design validation of Surveyor lunar roving vehicle - navigation, control and display, television, telecommunications, power supply, and thermal contro

Global Soil Biodiversity Atlas

Soils provide numerous ecosystem services. Most people do not know that the key drivers of soil ecosystems are the living organisms within the soil. Soils may be home to over one fourth of all living species on Earth, with a significant part not yet characterized. The first Global Soil Biodiversity Atlas is a product of the Global Soil Biodiversity Initiative. It aims at raising awareness of the importance and beauty of soil biodiversity among the general public and policy makers. Furthermore, it highlights the need to increase efforts to develop a global assessment of soil biodiversity. Data on distribution of soil-dwelling organisms are often difficult to combine. The atlas represents an attempt to create a unique network among soil biodiversity scientists. Such an effort may help in reaching the level of attention that research on soil biodiversity deserves. With contributions from over 80 experts in soil biodiversity from all over the world, and over 170 pages, the atlas will also display distribution maps of the main soil organisms. Furthermore, an exceptionally high number of images will allow non-specialists to get in touch with this fascinating and mysterious world.JRC.D.6-Knowledge for Sustainable Development and Food Securit

The 15th Aerospace Mechanisms Symposium

Technological areas covered include: aerospace propulsion; aerodynamic devices; crew safety; space vehicle control; spacecraft deployment, positioning, and pointing; deployable antennas/reflectors; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activities on the space shuttle orbiter are also described

Technology for large space systems: A bibliography with indexes (supplement 12)

A bibliography listing 516 reports, articles and other documents introduced into the NASA scientific and technical information system between July 1, 1984 and December 31, 1984 is presented. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design in the area of Large Space System Technology. Subject matter is grouped according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems

An advanced study of an Application Technology Satellite /ATS-4/ mission, volume I, book 3 Final study report, May - Nov. 1966

Flight dynamics, experiment operational phase sequence, and support operations for Applications Technology Satellite /ATS/ MISSIO

Macroevolution: Explanation, Interpretation and Evidence

info:eu-repo/semantics/publishedVersio

39th Aerospace Mechanisms Symposium

The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production, and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Education Association, NASA Marshall Space Flight Center (MSFC) and Lockheed Martin Space Systems Company (LMSSC) share the responsibility for hosting the AMS. Now in its 39th symposium, the AMS continues to be well attended, attracting participants from both the United States and abroad. The 39th AMS was held in Huntsville, Alabama, May 7-9, 2008. During these 3 days, 34 papers were presented. Topics included gimbals and positioning mechanisms, tribology, actuators, deployment mechanisms, release mechanisms, and sensors. Hardware displays during the supplier exhibit gave attendees an opportunity to meet with developers of current and future mechanism components