Life Sciences Program Tasks and Bibliography for FY 1996

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1996. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web page

Exploring unknown avenues of intra- and interspecies communication in Drosophila

The manuscripts within this dissertation aimed to investigate odor-mediated communication channels for the interactions of Drosophila flies with each other, other Drosophila species, and with microorganisms. Throughout the dissertation, I introduce the frass of adult Drosophila flies as a previously overseen intra- and possibly interspecies communication medium (manuscript I) and demonstrate the sensitivity of hardwired stereotypical behaviors, which are mediated by only a few chemosignals, to manipulation through harmful microbes (manuscript II). Furthermore, this dissertation highlights different factors that may be involved in Drosophila speciation events, such as niche partitioning (manuscript IV) and insect-microbe interactions (manuscript V). Finally, I worked on a previously described method that is used for the identification of ligand-receptor pairs of olfactory systems in mammals and tried to further establish this technique for the high-throughput identification of chemosensory receptor ligands in insects on the example of the vinegar fly D. melanogaster (manuscript III)

The biology of pollination and seed dispersal in Clivia (Amaryllidaceae)

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.Pollinator shifts have been implicated as drivers of angiosperm diversification. The hypothesis that a transition from bird to butterfly pollination took place in Clivia was tested, and floral traits investigated to determine which may have mediated the putative shift. Linking pollination systems with available phylogenies indicated a shift occurred from bird to butterfly pollination, accompanied by the evolution of upright trumpet-shaped flowers, scent emission and nectar volume reduction, whilst floral colouration and nectar chemistry remain unmodified. Results support the idea that pollinator shifts may explain major floral trait modifications during plant diversification. Breeding systems of Clivia were investigated, with the aims of demining the site and functional consequences of putative late-acting self-incompatibility (LSI). Results suggest that Clivia species are largely self-sterile as a result of LSI or severe inbreeding depression, but ovule discounting caused by self-pollination is not a major limitation on fecundity, and seed production appears to be mostly resource limited. Clivia miniata is pollinated virtually exclusively by butterflies. Functional significance of C. miniata floral traits were examined, with the aim of determining butterfly floral preferences and the functional basis of traits responsible for butterfly pollination. Colour is a key advertising signal, with orientation facilitating alighting, whilst size, scent, and shape also influence butterfly attraction. Dispersal mechanisms of numerous fleshy seeded Amaryllidaceae have been an enigma as seeds are unorthodox, toxic and unable to survive ingestion, yet packaged in brightly coloured fruits suggestive of animal dispersal. Dispersal and germination of Clivia miniata seeds was investigated. Results indicated consumption of fruit by primates which disperse seeds through non-ingestive spitting behaviour. The short distance of seed dispersal by primates is predicted to lead to restricted gene flow and genetic subdivision of populations. I conclude that shifts in pollination systems and the associated modification of suites of functional floral traits led to floral diversification in Clivia. Self-infertility in Clivia highlights pollinator dependence and pollination syndrome conformity reflects functional advertising signals. Gene flow appears to be governed by pollen flow and facilitated by pollinators rather than seed dispersal. Mating and breeding system evolution are likely a consequence of adaptation to isolated forest habitats

The effect of experience and floral traits on preferences and flower constancy in Eristalis tenax

Intraspecific pollen transfer is crucial for ensuring successful pollination and subsequent reproduction of many plant species. Mechanisms directly influenced by plants, that can increase the proportion of intraspecific pollen through their flower form (individual floral traits) are preferences and constancy of pollinators. The proportion of intraspecific pollen transfer increases with higher preferences or constancy of the pollinator. Pollinator preferences and constancy tend to change over its lifetime based on experience with the flowers they have visited. Very few studies have examined the effect of experience on preferences and especially constancy in relation to multiple floral traits in hoverflies (Syrphidae, Diptera), which are an important pollinator group. In this study, I investigated the degree of preference and constancy of common drone fly Eristalis tenax L (Syrphidae) as a function of two floral traits, colour and size, and as a function of experience. I did so by monitoring visits and flights in arrays of artificial flowers. The hoverflies were of two origins: naïve (reared under laboratory conditions, with no previous experience of visiting flowers) and experienced (captured in the wild with previous experience). Naïve individuals made decisions primarily based on colour, with size...Vnitrodruhový přenos pylu je klíčový pro zajištění úspěšného opylení a následného rozmnožení mnoha druhů rostlin. Existují mechanismy, kterými lze podíl pylu přeneseného mezi jedinci stejného druhu zvýšit na úkor podílu přeneseného mezi druhy. Mezi mechanismy přímo ovlivnitelné rostlinami prostřednictvím podoby květů (jejich jednotlivých znaků), patří preference a věrnost opylovačů. Čím více opylovač daný druh preferuje nebo mu vykazuje věrnost, tím roste podíl vnitrodruhového přenosu pylu. Projev preferencí a věrnosti zpravidla není v čase ustálený, nýbrž se může během života opylovače měnit na základě zkušeností s květy, které navštíví. Velmi málo studií se u opylovačů zabývalo efektem zkušeností na preference, a především na věrnost k více květním znakům u pestřenek (Syrphidae, Diptera), které představují významnou skupinu opylovačů. V této práci jsem zjišťovala míru preferencí a věrnosti u včelice trubcové Eristalis tenax (Syrphidae) v závislosti na dvou květních znacích - barvě a velikosti, a také v závislosti na míře zkušeností. Činila jsem tak pomocí sledování návštěv a přeletů na kombinacích umělých květů. Jedinci byli dvojího původu: naivní (odchovaní v laboratorních podmínkách, bez předchozích zkušeností s návštěvou květů) a zkušení (odchycení ve volné přírodě se zkušeností s návštěvou...Department of BotanyKatedra botanikyFaculty of SciencePřírodovědecká fakult

Spacelab Science Results Study

Beginning with OSTA-1 in November 1981 and ending with Neurolab in March 1998, a total of 36 Shuttle missions carried various Spacelab components such as the Spacelab module, pallet, instrument pointing system, or mission peculiar experiment support structure. The experiments carried out during these flights included astrophysics, solar physics, plasma physics, atmospheric science, Earth observations, and a wide range of microgravity experiments in life sciences, biotechnology, materials science, and fluid physics which includes combustion and critical point phenomena. In all, some 764 experiments were conducted by investigators from the U.S., Europe, and Japan. The purpose of this Spacelab Science Results Study is to document the contributions made in each of the major research areas by giving a brief synopsis of the more significant experiments and an extensive list of the publications that were produced. We have also endeavored to show how these results impacted the existing body of knowledge, where they have spawned new fields, and if appropriate, where the knowledge they produced has been applied

ANNUAL REPORT 1989-1990

Clemson University reports to the Office of State Budget its annual accountability report that includes a discussion and analysis, major accomplishments, strategic planning and performance measurement