Electroantennogram responses of tsetse flies (Glossina pallidipes) to host odours in an open field and riverine woodland

The present study was initiated to gain insight into the way in which tsetse flies ( Glossina spp.) sense odours at different locations in odour plumes in both an open field and a wooded area.
We recorded the antennal responses (EAGs) from stationary living female G. pallidipes 15 m upwind and at various (60, 40, 20, 10, 5 and 1 m) distances downwind from a synthetic host odour source (containing 1-octen-3-ol, acetone and two phenols), in the natural habitat of the fly (Zimbabwe) using a portable electrophysiological device. Experiments were performed in a flat open area (an airstrip) and in riverine woodland. Differences between responses in different environments were determined by comparing various parameters of the EAGs (intermittency, frequency, amplitude, duration and rate of depolarization).
We found that a fly senses odours as puffs that, further downwind, contain less odour and pass less frequently. In an open field downwind from the source, tsetse perceive more olfactory information than upwind for only 10–20 m, whereas in woodland, olfactory responses remain higher and more frequent than upwind up to at least 60 m. In an open field, olfactory information rapidly increases when approaching the odour source from 20 m and in woodland from 5 m onwards.
It is proposed that averaging odour information over time may be of minor importance in long-range location of odour sources. The results suggest that tsetse may smell odour-baited targets from at least 60 m downwind and that the number of flies responding to and being caught by these baits may be higher in woodland than in an open field.     

MORAL EXPERTISE: A PROBLEM IN THE PROFESSIONAL ETHICS OF PROFESSIONAL ETHICISTS

Philosophers, particularly moral philosophers, are increasingly being involved in public decision-making in areas which are seen to raise ethical issues. For example, Dame Mary Warnock chaired the ‘Committee of Inquiry into Human Fertilization and Embryology’ in the UK in 1982–4; the Philosophy Department at Auckland was commissioned by the Auckland Regional Authority to report on the ethical aspects of fluoridating the public water supply in 1990; and many of us are serving on ethics committees of various sorts. Not only are philosophers actually being called on or consulted, but many of us would argue that a philosophical contribution in such areas is essential. The involvement of moral philosophers in public policy decisions raises a question of professional ethics, viz, what role should a philosopher's own moral perspective or judgements play in the advice s/he gives, or contribution s/he makes, to public decision-making on ethical issues. Like most problems in professional ethics, this prompts reflection on the nature of the profession, and in particular on the expertise we take moral philosophy to offer. It also prompts reflection on how processes of public decision making in ethically problematic areas should be understood. I explore these issues in this paper.     

Molecular Identification of Algal Endosymbionts in Large Miliolid Foraminifera: 1. Chlorophytes

Large miliolid foraminifers bear various types of algal endosymbionts including chlorophytes, dinoflagellates, rhodophytes, and diatoms. Symbiosis plays a key role in the adaptation of large foraminifera to survival and growth in oligotrophic seas. The identity and diversity of foraminiferal symbionts, however, remain largely unknown. In the present work we use ribosomal DNA (rDNA) sequences to identify chlorophyte endosymbionts in large miliolid foraminifera of the superfamily Soritacea. Partial 18S and complete Internal Transcribed Spacer (ITS) rDNA sequences were obtained from symbionts of eight species representing all genera of extant chlorophyte-bearing Soritacea. Phylogenetic analysis of the sequences confirms the previous fine structure-based identification of these endosymbionts as belonging to the genus Chlamydomonas. All foraminiferal symbionts form a monophyletic group closely related to Chlamydomonas noctigama. The group is composed of seven types identified in this study, including one previously morphologically described species, Chlamydomonas hedleyi. Each of these types can be considered as a separate species, based on the comparison of genetic differences observed between other established Chlamydomonas species. Several foraminiferal species share the same symbiont type, but only one species, Archaias angulatus, was found to bear more than one type.     

Diurnal variations in the auto- and heterotrophic activity of cyanobacterial phycospheres (Gloeotrichia echinulata) and the identity of attached bacteria

1. We assessed the role of cyanobacterial–bacterial consortia (Gloeotrichia echinulata phycospheres) for net changes in inorganic carbon, primary production (PP) and secondary production in Lake Erken (Sweden). 2. At the time of sampling, large colonies of G. echinulata formed a massive bloom with abundances ranging from 102 colonies L^?1 in the pelagic zone to 5000 colonies L^?1 in shallow bays. These colonies and their surrounding phycospheres contributed between 17 and 92% of total PP, and phycosphere‐associated bacteria contributed between 8.5 and 82% of total bacterial secondary production. PP followed a diurnal cycle, whereas bacterial production showed no such pattern. Over a 24 h period, carbon dioxide measurements showed that the phycospheres were net autotrophic in the top layer of the water column, whereas they were net heterotrophic below 2 m depth. 3. Sequencing and phylogenetic analysis of 16S rRNA genes of attached bacteria revealed a diverse bacterial community that included populations affiliated with Proteobacteria, Bacteriodetes, Acidobacteria, Fusobacteria, Firmicutes, Verrucomicrobia, and other Cyanobacteria. 4. Compared with their planktonic counterparts, bacteria associated with cyanobacterial phycospheres had lower affinity for arginine, used as a model compound to assess uptake of organic compounds. 5. Extrapolation of our data to the water column of lake Erken suggests that microorganisms that were not associated with cyanobacteria dominated CO₂ production at the ecosystem scale during our experiments, as CO₂ fixation balanced CO₂ production in the cyanobacterial phycospheres.     

Local adaptation of developmental time and starvation resistance in eight Drosophila species of the Philippines

The ecological trade-off between developmental time and starvation resistance, acting in a heterogeneous environment, can promote the coexistence of competing species. Heterogeneity results from variation in the vegetation that influences both abiotic (e.g. temperature, humidity) and biotic (e.g. fruit availability during the year) aspects of the environment. In this study, we investigated whether differences between collection sites have led to local differentiation of the two life-history traits underlying the coexistence model: developmental time and starvation resistance. Drosophila were collected from four collection sites, ranging from grassland to secondary forest, along a transect of 15 km. The microclimatic and vegetation differences among these collection sites were considerable. For developmental time, different species showed similar genetic responses to the (habitat) differences between the different collection sites. The shortest developmental times were found in the secondary forest populations and the agricultural area populations, the longest in the grassland populations, and the forest edge populations were intermediate. However, there was no correlation between the habitat ranking based on disturbance and canopy cover, and the ranking of the developmental times. Furthermore, the data did not confirm the generality of the positive correlation between developmental time and starvation underlying the coexistence model.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87 , 115–125.     

The functional significance of multiple nest-building in the Australian Reed Warbler Acrocephalus australis

The vast majority of bird species build a nest in which to breed. Some species build more than one nest, but the function of most multiple nest-building remains unclear. Here we describe the unusual nest-building behaviour of the Australian Reed Warbler Acrocephalus australis , and test experimentally the hypotheses that multiple nest-building is related to individual condition or territory quality, and plays a role in mate assessment. Australian Reed Warblers built two types of nest structures: 'type I' nests, which were used for eggs and nestlings, and 'type II' nests, which were structurally distinct from type I nests, did not support eggs, nestlings or adults and were not essential for successful breeding. The number of type II nests built in each territory varied. Type II nests were only built before breeding had commenced in a territory and females were not observed participating in their construction, supporting a role in female mate choice. Birds provided with supplementary food built significantly more type II nests than control birds. However, supplementary-fed birds did not have greater pairing success, and the addition of further type II nests to territories did not increase the pairing rate or type II nest construction in those territories. There was no relationship between the presence of type II nests and either reproductive success or likelihood of nest predation. We discuss the implications of these results in light of previous suggestions regarding the function of multiple nest-building in birds.     

Phosphorylation regulated ion-binding is a property shared by the acidic subclass dehydrins

Dehydrins are a family of proteins that accumulate in response to abiotic stresses. Little is known about the biochemical functions of these proteins. It is known that the Arabidopsis dehydrin, ERD14, is activated by phosphorylation to bind calcium and other ions. To begin to categorize the Arabidopsis dehydrins into functional families, we determined whether representative members of the dehydrin sub families share the properties of ERD14. When phosphorylated in vitro with casein kinase II; recombinant COR47, and ERD10 (and ERD14) become activated to bind calcium. ERD14 exhibited the highest calcium-binding activity followed by ERD10 and COR47. These dehydrins, when isolated from cold-treated Arabidopsis plants were also shown to have phosphorylation-dependent, calcium-binding activity. RAB18 showed very little calcium binding activity, even though it was phosphorylated by casein kinase II. XERO2 was not phosphorylated with CKII and did not bind calcium. Competition studies suggest that other divalent cations may bind to the dehydrins COR47, ERD10, and ERD14. Utilizing matrix-assisted laser desorption ionization – time of flight mass spectroscopy (MALDI-TOF), we determined that the poly serine region located in all three calcium-binding family members (COR47, ERD10, and ERD14) is the most likely phosphorylation site responsible for the activation of calcium binding. These results are consistent with a distinct biochemical function for the acidic subclass of dehydrins (COR47, ERD10, and ERD14) as ion (calcium)-interacting proteins.     

THE MORPHOLOGY OF HYOLITHIDS AND ITS FUNCTIONAL IMPLICATIONS

Abstract:  The exceptionally preserved hyolithids Gompholites striatulus , Maxilites robustus , Maxilites snajdri and Maxilites sp. are described with particular emphasis on helen and muscle scar morphology. These two aspects of hyolithid morphology have remained controversial. In life position, each helen curved ventrally. When the operculum closed the aperture of the conch, each helen was locked at the commissure slit with its dorsal edge tilted forward. Inside the conch, it was held in the dorsal apertural plane and clear of the inner surface of the operculum. Previously unidentified muscle scars are described from both the operculum and the conch. Dorsal scars on the conch aperture held muscles directed to the operculum. Comparative study of the muscle insertion pattern indicates that hyolithids did not have serially arranged muscles and that all hyolithids may have had a common skeleto-muscular system. The arrangement of the muscle scars with respect to the helens suggests that the latter were capable of relatively complex movements and could have been used to propel the organism over the substrate. The general morphology and orientation of the helens suggests that in addition they functioned to stabilize the organism on the sea-floor.