The moult of Barred Warblers Sylvia nisoria in Kenya—evidence for a split wing-moult pattern initiated during the birds' first winter*

The moult of Barred Warblers Sylvia nisoria was studied during three winter seasons in southeastern Kenya at a southward passage site (Ngulia) and a wintering site (Mtito Andei). Most Barred Warblers migrating through Ngulia in November had yet to commence winter moult. These birds probably moulted subsequently in winter in northern Tanzania. In December, birds were found in heavy moult at Mtito Andei, and some of these birds were known to stay throughout the winter. By contrast, most birds reaching southeastern Kenya from late December onwards had already completed part or all of their winter moult, presumably at stopover sites in northern and eastern Kenya or in Ethiopia. Thus, winter moult in Barred Warblers takes place mainly in late November and December, either just before or soon after the final leg of autumn migration. In general, first-year birds renewed all tertials and tail feathers, about three to five secondaries per wing and commonly also the outer one to four large primaries per wing. Adults renewed all tertials and tail feathers, almost all secondaries and only occasionally an outer primary. The replacement of relatively fresh juvenile secondaries during the birds' first winter implies that the split moult pattern of this species (secondaries, tertials and tail moulted in winter; primaries and tertials in summer) is endogenously controlled.     

Migration, stopover and moult of the Great Reed Warbler Acrocephalus arundinaceus in Ghana, West Africa

We studied Great Reed Warblers Acrocephalus arundinaceus at two localities in Ghana during the winter. In the north (Tono), the birds arrived from late September and conducted a rapid moult soon after arrival. Towards the end of moult, birds accumulated fat and disappeared from the site. In the south (Tafo), birds arrived from mid-November in fresh plumage. This seemed to be the final wintering area as birds stayed there during the winter. In March-April they again accumulated fat, although only small amounts, before spring migration back to breeding areas.     

Tumor Gene Expression and Interphase Chromatin Appearance in Xiphophorus

SYNOPSIS. Xiphophorus maculatus (platyfish) exhibits spots whichconsist of neoplastically transformed pigment cells (T-cells).The spots actually represent extreme benign melanomas. Transformationto T-cells is mediated by a "tumor gene" (Tu). Platyfish whichdevelop from X-irradiated embryos reveal an increase of Tu-expressionresulting in an overproduction of T-cells to benign melanomaswhich can be compared to that observed in certain hybrids betweenthe platyfish and Xiphophorus helleri (swordtail). Both theX irradiation-induced and the crossing conditioned increaseof Tu-expression represent a heritable alteration which mightbe related to a conversion from dispersed to condensed chromatinin the interphase nuclei.     

How is host egg mimicry maintained in the cuckoo (Cuculus canorus)?

To investigate the evolutionary mechanism (host specificity vs. random searching) maintaining mimicry between cuckoo egg appearance and that of different European cuckoo Cuculus canorus hosts, we studied the level of mimicry between the appearance of C. canorus eggs and that of their hosts' eggs in different habitats in southern Finland by using ultraviolet-visible reflectance spectrophotometry. In the main habitat used by C. canorus for reproduction, eggs laid in nests of different host species differed in appearance. Host use by C. canorus was not related to the abundance of hosts, and the level of mimicry was not related to host abundance in the habitat. Furthermore, a close match between C. canorus egg appearance and that of host eggs within habitats was detected after removing the potentially confounding effect of host abundance. In the only two suitable host species nesting in trees (namely chaffinch Fringilla coelebs and brambling Fringilla montifringilla ) we detected changes in C. canorus egg appearance that paralleled those of the two host species. Thus our findings suggest the existence of a correlation between the appearance of C. canorus eggs and that of their hosts' eggs within different habitat types, and suggest that mimicry is maintained by strict host preferences by each C. canorus female when laying.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 57–68.     

Dissolved organic carbon, seston and macroinvertebrate drift in an acidified and limed humic stream

SUMMARY. 1. Total seston, and invertebrate drift were studied before and after lime addition to Fyllean River, a stream-iake system in Halland county, southwest Sweden, with poorly buffered waters undergoing acidification. 2. The largest effect of liming was on the chemistry of the water. Following liming with 23 mg CaCO₃ l^?1 the pH of the water changed from 5.8 to 6.8 and alkalinity from 0.04 to 0.13 meq l^?1.Turbidity increased from 3.4 to 4.7 JTU with no change in colour. 3. Dissolved organic carbon (DOC) concentration of all samples was in the range 10.7–13.3 mg C l^?1 with no significant change occurring due to liming. 4. Total seston increased from 4.35 mg DM 1^?1 in unlimed conditions to 6.25 mg DM l^?1 after lime addition. All significant changes in seston occurred in the smaller size fraction (0.45–25 μm). 5. Liming reduced the organic content of the partieulate material from an average of 61% to 39% immediately downstream of a lime silo (within 1 km) but had little effect when the river course was interrupted by lakes and impoundments. 6. The lakes in the river system had a larger effect on seston concentration than any effect of the lime addition by itself. Particle concentrations were reduced by 50–55% and DOC by about 1 mg C l^?1as the water passed through the lakes. 7. Macroinvertebrate drift density was low in all samples before and after liming and typical of oligotrophic streams. Drift was significantly lower at limed (0.024 ind. m^?3) than at unlimed (0.083 ind. m^?3) locations. The decrease was only in total drift density with no significant change in the relative abundance of functional groups or in densities of single taxa, except for a reduction in drift of predators in the limed condition.     

Attractive blue‐green egg coloration and cuckoo−host coevolution

Recent evidence suggests that blue‐green coloration of bird eggshells may be related to female and/or egg phenotypic quality, and that such colour may affect parental effort and therefore the nutritional environment of developing nestlings. Here we suggest that these relationships and the signal function of eggshell coloration would affect the outcome of coevolution between avian brood parasites and their hosts in at least three different non‐exclusive evolutionary pathways. First, by laying blue‐green coloured eggs, cuckoo females may exploit possible sensory biases of their hosts, constraining the evolution of parasitic egg recognition, and thus avoid rejection. Second, because of the relatively high costs of laying blue eggs, cuckoo females may be limited in their ability to mimic costly blue‐green eggs of their hosts because cuckoo females lay many more eggs than their hosts. Furthermore, costs associated with foreign egg recognition errors would be relatively higher for hosts laying blue eggs. Third, cuckoos may use coloration of host eggs for selecting individuals or specific hosts of appropriate phenotypic quality (i.e. parental abilities). We here explored some predictions emerging from the above scenarios and found partial support for two of them by studying egg coloration of European cuckoos (Cuculus canorus) and that of their 25 main hosts, as well as parasitism and rejection rate of hosts. Cuckoo hosts parasitized with more blue, green, and ultraviolet cuckoo eggs, or those laying more blue‐green eggs, were more prone to accept experimental parasitism with artificial cuckoo eggs. In addition, coloration of cuckoo eggs is more variable when parasitizing hosts laying bluer‐greener eggs, even after controlling for the effect of host egg coloration (i.e. degree of egg matching). Globally, our results are consistent with the proposed hypothesis that host egg traits that are related to phenotypic quality of hosts, such as egg coloration, may have important implications for the coevolutionary interaction between hosts and brood parasites. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 154–168.     

Provannid and provannid‐like gastropods from the Late Cretaceous cold seeps of Hokkaido (Japan) and the fossil record of the Provannidae (Gastropoda: Abyssochrysoidea)

A fauna of provannid and provannid‐like shells is described from Upper Cretaceous seep carbonates in Hokkaido, Japan. We describe two new provannid species, Provanna tappuensis sp. nov. and Desbruyeresia kanajirisawensis sp. nov. , with preserved protoconchs of unquestionable provannid type with decollate apex. This material confirms the occurrence of Provannidae as early as the Middle Cenomanian. We also describe Hokkaidoconcha gen. nov. and a new family Hokkaidoconchidae fam. nov. , with two named species, H. hikidai sp. nov. and H. tanabei sp. nov . Hokkaidoconchidae are possibly related to the Provannidae, judging from a similar, but not decollate larval shell, although the juvenile teleoconch whorls differ in being of a general cerithimorph appearance and the details of the aperture are unknown. Furthermore, we review the published fossil record of Provannidae and Abyssochrysidae, and we consider that in those older than the Eocene, there is no evidence preserved that unequivocally supports a position there. The Jurassic Acanthostrophia acanthica from Italy seems to be the oldest known record of Abyssochrysidae, and the most reliable occurrence of the family, older than from the Miocene. Other fossil, pre‐Miocene species that have been classified in the Abyssochryssidae are provisionally referred to Hokkaidoconchidae. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 421–436.