International cues for 4-H leaders and extension staff.

Mode of access: Internet.

The missionary pioneer : or, A brief memoir of the life, labours, and death of John Stewart, (man of colour,) founder, under God, of the mission among the Wyandotts, at Upper Sandusky, Ohio, /

Photocopy. Ann Arbor, Mich. : University Microfilms International, 1980.--21 cm.

Journal of Daniel Coker, : a descendant of Africa, from the time of leaving New York, in the ship Elizabeth, Capt. Sebor, on a voyage for Sherbro, in Africa, in company with three agents, and about ninety persons of colour. : The Rev. Samuel Bacon, John B. Bankson, Samuel S. Crozer. Agents. : With an appendix.

"Appendix to the Rev. D. Coker's Journal" (pages [41]-52) includes "Letter from Nathaniel Peck to his mother in Baltimore".

Catalogue of a loan exhibition of Japanese colour prints.

Mode of access: Internet.

The physiology of vision with special reference to colour blindness.

Mode of access: Internet.

Ancient colour vision: Multiple opsin genes in the ancestral vertebrates

Molecular investigation of the origin of colour vision has discovered five visual pigment (opsin) genes, all of which are expressed in an agnathan (jawless) fish, the lamprey Geotria australis. Lampreys are extant representatives of an ancient group of vertebrates whose origins are thought to date back to at least the early Cambrian, approximately 540 million years ago [1.]. Phylogenetic analysis has identified the visual pigment opsin genes of G. australis as orthologues of the major classes of vertebrate opsin genes. Therefore, multiple opsin genes must have originated very early in vertebrate evolution, prior to the separation of the jawed and jawless vertebrate lineages, and thereby provided the genetic basis for colour vision in all vertebrate species. The southern hemisphere lamprey Geotria australis (Figure 1A,B) possesses a predominantly cone-based visual system designed for photopic (bright light) vision [2. S.P. Collin, I.C. Potter and C.R. Braekevelt, The ocular morphology of the southern hemisphere lamprey Geotria australis Gray, with special reference to optical specializations and the characterisation and phylogeny of photoreceptor types. Brain Behav. Evol. 54 (1999), pp. 96–111.2. and 3.]. Previous work identified multiple cone types suggesting that the potential for colour vision may have been present in the earliest members of this group. In order to trace the molecular evolution and origins of vertebrate colour vision, we have examined the genetic complement of visual pigment opsins in G. australis.

The surface brightness and colour-magnitude relations for Fornax cluster galaxies

We present BVI photometry of 190 galaxies in the central 4 x 3 deg(2) region of the Fornax cluster observed with the Michigan Curtis Schmidt Telescope. Results from the Fornax Cluster Spectroscopic Survey (FCSS) and the Flair-II Fornax Surveys have been used to confirm the membership status of galaxies in the Fornax Cluster Catalogue (FCC). In our catalogue of 213 member galaxies, 92 (43 per cent) have confirmed radial velocities. In this paper, we investigate the surface brightness-magnitude relation for Fornax cluster galaxies. Particular attention is given to the sample of cluster dwarfs and the newly discovered ultracompact dwarf galaxies (UCDs) from the FCSS. We examine the reliability of the surface brightness-magnitude relation as a method for determining cluster membership and find that at surface brightnesses fainter than 22 mag arcsec(-2), it fails in its ability to distinguish between cluster members and barely resolved background galaxies. Cluster members exhibit a strong surface brightness-magnitude relation. Both elliptical (E) galaxies and dwarf elliptical (dE) galaxies increase in surface brightness as luminosity decreases. The UCDs lie off the locus of the relation. B-V and V-I colours are determined for a sample of 113 cluster galaxies and the colour-magnitude relation is explored for each morphological type. The UCDs lie off the locus of the colour-magnitude relation. Their mean V - I colours (similar to1.09) are similar to those of globular clusters associated with NGC 1399. The location of the UCDs on both surface brightness and colour-magnitude plots supports the 'galaxy threshing' model for infalling nucleated dwarf elliptical (dE, N) galaxies.

Coloured oil droplets enhance colour discrimination

The eyes of most diurnal reptiles and birds contain coloured retinal filters-oil droplets. Although these filters are widespread, their adaptive advantage remains uncertain. To understand why coloured oil droplets appeared and were retained during evolution, I consider both the benefits and the costs of light filtering in the retina. Oil droplets decrease cone quantum catch and reduce the overlap in sensitivity between spectrally adjacent cones. The reduction of spectral overlap increases the volume occupied by object colours in a cone space, whereas the decrease in quantum catch increases noise, and thus reduces the discriminability of similar colours. The trade-off between these two effects determines the total benefit of oil droplets. Calculations show that coloured oil droplets increase the number of object colours that can be discriminated, and thus are beneficial for colour vision.

Intraspecific and intraspecific views of colour signals in the strawberry poison frog Dendrobates Pumilio

Poison frogs in the anuran family Dendrobatidae use bright colors on their bodies to advertise toxicity. The species Dendrobates pumilio Schmidt 1858, the strawberry poison frog, shows extreme polymorphism in color and pattern in Panama. It is known that females of D. pumilio preferentially choose mates of their own color morph. Nevertheless, potential predators must clearly see and recognize all color morphs if the aposermatic signaling system is to function effectively. We examined the ability of conspecifics and a model predator to discriminate a diverse selection of D. pumilio colors from each other and from background colors. Microspectrophotometry of isolated rod and cone photoreceptors of D. pumilio revealed the presence of a trichromatic photopic visual system. A typical tetrachromatic bird system was used for the model predator. Reflectance spectra of frog and background colors were obtained, and discrimination among spectra in natural illuminants was mathematically modeled. The results revealed that both D. pumilio and the model predator discriminate most colors quite well, both from each other and from typical backgrounds, with the predator generally performing somewhat better than the conspecifics. Each color morph displayed at least one color signal that is highly visible against backgrounds to both visual systems. Our results indicate that the colors displayed by the various color morphs of D. pumilio are effective signals both to conspecifics and to a model predator.

Ecology and evolution of primate colour vision

More than one hundred years ago, Grant Allen suggested that colour vision in primates, birds and insects evolved as an adaptation for foraging on colourful advertisements of plants-fruits and flowers. Recent studies have shown that well developed colour vision appeared long before fruits and flowers evolved. Thus, colour vision is generally beneficial for many animals, not only for those eating colourful food. Primates are the only placental mammals that have trichromatic colour vision. This may indicate either that trichromacy is particularly useful for primates or that primates are unique among placental mammals in their ability to utilise the signals of three spectrally distinct types of cones or both. Because fruits are an important component of the primate diet, primate trichromacy could have evolved as a specific adaptation for foraging on fruits. Alternatively, primate trichromacy could have evolved as an adaptation for many visual tasks. Comparative studies of mammalian eyes indicate that primates are the only placental mammals that have in their retina a pre-existing neural machinery capable of utilising the signals of an additional spectral type of cone. Thus, the failure of non-primate placental mammals to evolve trichromacy can be explained by constraints imposed on the wiring of retinal neurones.

Eye colour: portals into pigmentation genes and ancestry

Several recent papers have tried to address the genetic determination of eye colour via microsatellite linkage, testing of pigmentation candidate gene polymorphisms and the genome wide analysis of SNP markers that are informative for ancestry. These studies show that the OCA2 gene on chromosome 15 is the major determinant of brown and/or blue eye colour but also indicate that other loci will be involved in the broad range of hues seen in this trait in Europeans.

Communication in coral reef fish: the role of ultraviolet colour patterns in damselfish territorial behaviour

Many coral reef fish possess ultraviolet (UV) colour patterns. The behavioural significance of these patterns is poorly understood and experiments on this issue have not been reported for free-living reef fish in their natural environment. The damselfish Pomacentrus amboinensis has UV facial patterns, and spectroradiometric ocular media measurements show that it has the potential for UV vision. To test the potential behavioural significance of the UV patterns, I studied the response of males, in natural territories on the reef and in aquaria, to two conspecific intruders, one presented in a UV-transmitting (UV+) container and the other in a UV-absorbing (UV-) one. Territory owners attacked intruders viewed through UV+ filters significantly more often and for longer than intruders viewed through the UV- filter. In general, the results of the field experiment confirmed those of the laboratory experiment. The results support the hypothesis that P. amboinensis males are sensitive to UV light and that reflectance patterns, which appear in high contrast only in UV, modulate the level of aggressive behaviour. A recent survey showed that many predatory fish may not have UV vision and the use of UV colours in select species of reef fish may therefore serve as a 'private communication channel'. (C) 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Esterified astaxanthin levels in lobster epithelia correlate with shell colour intensity: Potential role in crustacean shell colour formation

Carotenoids, particularly astaxanthin, are the primary pigment in crustacean shell colour. Sub-adults of the western rock lobster, Panulirus cygnus, moult from a deep red colour (termed the red phase) to a much paler colour (the white phase) at sexual maturation. We observe a 2.4-fold difference in the amount of total carotenoid present in the shell extracts of reds compared to whites, as might be expected. However, analysis of the underlying epithelium shows that there is no correlation with shell colour and the amount of free (unesterified) astaxanthin-the level of free astaxanthin in reds and whites is not significantly different. Instead, we observe a correlated two-fold difference in the amount of esterified astaxanthin present in the epithelium of red versus white individuals. These data suggest a role for esterified astaxanthin in regulating shell colour formation and suggest that esterification may promote secretion and eventual incorporation of unesterified astaxanthin into the exoskeleton. (c) 2005 Elsevier Inc. All rights reserved.

Experience overrides colour in lizard contests

We examined the role of conspicuous coloration in male-male contests for two species of Australian dragon lizards, Ctenophortis decresii and C. vadnappa, in which conspicuous coloration has a demonstrated predation cost. We conducted contests in which the overall conspicuousness of male coloration was manipulated using paints that matched the spectral reflectance of the lizards, as well as natural (control) contests. There was little evidence for an influence of colour on contest outcome or aggression levels for either species when all experiments were considered. However, we found a significant effect of trial order and experience on contest outcome and aggression levels (the same pair of males was used for both types of contest), despite a 2-3 week interval between contests. When we examined only the first trial between unfamiliar males, we found that male C. vadnappa that had been painted to appear more conspicuous consistently won. Comparison with the natural trials suggests that the aspect of colour manipulation that was responsible for this result was the 'hue' of the throat: males with yellower throats consistently beat males with bluer throats in both natural and painted trials. The difference in coloration of flank markings also predicted the difference in aggression scores between contestants in the natural trials. These results suggest that although colour is important in opponent assessment and in determining contest outcome in C vadnappa, previous agonistic experience can override the effects of colour and have a long-lasting influence on aggressive behaviour.