Contrasting levels of extra-pair paternity in mainland and island populations of the house sparrow (Passer domesticus): is there an 'island effect'?

Despite the many studies that have investigated the genetic mating system of socially monogamous birds, very little is known about the underlying causes of extra-pair paternity and few studies have attempted to test those hypotheses which have been suggested. This study describes die analysis of die genetic mating system of two populations of the house sparrow [Passer domesticus) , and uses the results from four other populations to test existing hypodieses using an intra-specific comparative approach. The parentage analysis was conducted using a combination of published and newly presented microsatellite loci isolated from the house sparrow. One population in Kentucky, U.S.A. was found to contain what may be considered to be a typical level of extra-pair paternity for mis species (10.5%, 19/185 offspring). The second, a population on the island of Lundy, UK, exhibited a very low level (1.3%, 4/305 offspring), significandy lower dian that in all the other populations studied so far. The finding of such diverse rates of extra-pair paternity, along with the existing estimates from ofher populations, has allowed us to test the effects of breeding density and genetic variation on die level of extra-pair paternity. We found no effect of either factor on the frequency of extra-pair paternity in the house sparrow, leaving the cause of this variation open to fresh ideas.     

Isolation of 18 polymorphic microsatellite loci from the North American red squirrel,Tamiasciurus hudsonicus (Sciuridae,Rodentia), and their cross‐utility in other species

We isolated 18 polymorphic microsatellite loci to be used for pedigree analysis in a wild population of North American red squirrels, Tamiasciurus hudsonicus. Allelic diversity and observed heterozygosity ranged from six to 13 and 0.39 to 0.89, respectively, in a sample of 93 individuals. Up to 13 sets of primers also amplify in other rodent species.     

Salt Tolerance in Cell Suspension Cultures of the Halophyte Kosteletzkya virginica

Tolerance to NaCl was studied in cell suspension cultures ofKosteletzkya virginica (L.) Presl. (Malvaceae), a dicotyledonoushalophyte that grows in tidal marshes of the eastern UnitedStates. Growth of salinized cultures was significantly inhibitedat high (255 mol m^–3 NaCl), but not at lower externalsalinities. Adjustment of cell suspensions to Nacl was rapid,with the duration of the normal growth cycle unaffected by salinity.Maximum biomass was attained when cultures were exposed to NaClduring early log growth. Patterns of inorganic ion accumulationreflected the utilization of both Na⁺ and K⁺ as osmotica, withNa⁺ content substantially increasing when cells were grown atan external salinity sufficient to reduce growth. K⁺ uptakeselectivity was high and Na⁺/K⁺ ratios were low in salt-treatedcultures even though K⁺ content was somewhat lower comparedto unsalinized cultures. Free proline and microsomal lipid contentincreased in salt-treated cell cultures. Key words: Kosteletzkya virginica, halophyte, salt tolerance, cell suspension culture     

The importance of olfactory signals in the gasterosteid mating system: sticklebacks go multimodal

Stickleback fishes are renowned for the complexity of their nuptial colour signal. In this paper I show that the nuptial signal is in fact multimodal: male-based olfactory cues also transmit information to receptive females. Both female three-spined and brook sticklebacks recognized the scent from each other's males, but discriminated in favour of their own males when asked to choose between conspecific and heterospecific odours. Although females were not attracted to scent from the more distantly related guppy, Poecilia reticulata , changes in their baseline behaviours indicated that they perceived its presence. Olfactory cues act as long distance messages, allowing a female to detect the 'I am here' message from the male before she can actually see him. Studies of interactions between temporally displaced signals indicate that the first cue (in this case chemical) functions to alert the receiver to the presence of the second cue (visual), increasing the probability of its detection and recognition. So, although olfactory cues do not appear to be as species-specific as visual cues, their function as alerting stimuli may not require such fine-tuning. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 555–572.     

Fine-scale genetic structure and its consequence in breeding aggregations of a passerine bird

The pattern of fine-scale genetic structure in a population may reflect current biological processes of the species, such as natal dispersal, the breeding system and demography. We investigated the spatial distribution of nests and fine-scale genetic structure during two breeding seasons in a population of a weakly territorial, flock-living passerine bird, the vinous-throated parrotbill, Paradoxornis webbianus . Nest distribution was clustered. There were two peaks of egg laying within each breeding season, and spatial clustering of nests was more extreme during the second peak after controlling for breeding density. The patterns of genetic structure during the breeding season varied with parental sex and season. Genetic structure occurred during the second laying peak: males breeding within 200 m of one another at this time were significantly more closely related than males breeding farther apart. However, no apparent genetic structure was detected in males during the first laying peak or among females in either laying peak. These results reveal male-oriented kin affiliation during part of the breeding season in this species. Furthermore, juvenile recruitment into the winter flocks was positively related to this increased relatedness among males via kin affiliation. This study implies that fine-scale genetic structure during the breeding season could be a factor determining individual fitness and may play an important role in our understanding of the evolution of social systems.     

Callaloo Nation: Metaphors of Race and Religious Identities among South Asians in Trinidad

Callaloo Nation: Metaphors of Race and Religious Identities among South Asians in Trinidad . Aisha Khan. Durham, NC: Duke University Press, 2004. 264 pp.     

Natal Den Selection by Florida Panthers

ABSTRACT Information regarding habitat types selected by federally endangered Florida panthers (Puma concolor coryi) at natal den sites is needed because habitats used for parturition and kitten rearing potentially influence fitness of individuals and viability of the population. We located 51 natal den sites of 30 female panthers and performed a Euclidean distance analysis to determine which habitat types were selected and avoided at dens in south Florida, USA. Panther dens were closer to upland hardwoods, pinelands, and mixed wet forests (P ≤ 0.003) and farther from freshwater marsh-wet prairie (P = 0.009). We recommend that habitat protection efforts prioritize blocks of land that have abundant patches of upland hardwood, pinelands, and mixed wet forests to maintain preferred panther denning habitat.