Juvenile sex ratio in relation to breeding success in Capercaillie Tetrao urogallus and Black Grouse T. tetrix

We examined the relationship between breeding success and juvenile sex ratio in two gamebirds with differing degrees of sexual size dimorphism. We used breeding success as an indicator of the level of environmental stress the birds had experienced. Capercaillie Tetrao urogallus and Black Grouse T. tetrix wing samples were collected from hunters in northern Sweden during 1977-86. In both species, annual juvenile sex ratio (percentage of males) increased with annual breeding success, i.e. with reduced environmental stress. We attribute this to the higher energy requirements during growth, vulnerability to environmental stress, and mortality of juvenile males compared with females, especially under adverse conditions. Moreover, the relationship between breeding success and juvenile sex ratio was stronger in Capercaillie than in Black Grouse. This reflects the higher degree of sexual size dimorphism in Capercaillie, and consequent larger mortality difference between juvenile males and females.     

The distribution of mammal body masses

How the diversity of organisms relates to their body sizes has long been a question of interest to biologists, an interest that has grown as data have become available from an increasing number of taxa at ever larger spatial scales. Here, we examine the form of this relationship for a large proportion of the global placental mammal fauna. In common with other large-scale assemblages, the frequency distribution of mammal body masses is strongly right-skewed, even after logarithmic transformation. The modal body mass is slightly lower than predicted by a recent energetic fitness model, but the exact modal value depends on the taxonomic inclusivity of the analyses. Moreover, threatened species are larger bodied than expected by chance, suggesting that extinct species may also have been so. Therefore, the loss of large-bodied species from the global mammalian fauna could potentially have lowered the mode of the distribution. However, this loss must be balanced against evidence that most mammal species for which body mass data were not available for our analyses are small-bodied, which may in turn raise the apparent mode of the distribution. Clearly, tests of explanations for patterns in body size frequency distributions will be complicated by the fact that present-day distributions may be significantly biased by species that are missing from them.     

Relationships between abundance and body size: where do tourists fit?

Abstract.

• 1 The possible effects of the inclusion of ‘tourist’ species have been the cause of some concern in investigations of interspecific relationships between abundance and body size.
• 2 Data for adult beetles (Coleoptera) from oak trees in Britain are used to investigate the relationship of abundance to body size when tourists are and are not included.
• 3 For this particular assemblage, tourists do not fundamentally alter the basic statistics of the relationship between abundance and body size. However, they are not a random sample of the beetle assemblage. They have lower abundances and are also of smaller body size than other species.

     

Strong relationship between coral bleaching and growth anomalies in massive Porites

Reports of coral diseases are increasing and may result from human land use and climate change conditions such as increased water temperature, coral bleaching, runoff from land, and changes in the ecology of heavily fished reefs. We examined a stable coral syndrome or a growth anomaly [ Porite growth anomaly (PGA)] (skeletal tissue anomaly, hyperplasia, or 'tumor') that was present in 0–15% of massive Porites colonies in 12 Kenyan reef lagoons. At the level of the calice morphology, this growth anomaly showed larger calices with less distance between calices and some calices with higher than normal numbers of septa, which indicate the influence of microboring organisms. Scanning electron micrographs of affected corals revealed a high abundance of fungal hyphae, a potential microboring pathogenic agent. To test the hypothesis that the PGA covaries with environmental variables, we evaluated its prevalence in relationship to 16 parameters of water quality, temperature, intensity of bleaching, benthic composition, and management at the end of the 2005 warm season. Stepwise regression models found eight environmental variables significantly associated with the frequency of the PGA, and the site's bleaching intensity was the most strongly associated variable. When bleaching intensity was removed from the dataset, the concentration of phosphorus was the one significant and positively associated variable, which suggest that the other significant environmental variables were associated with bleaching and not the growth anomalies. Our hypothetical model of causation is that the patchy loss of symbionts, often associated with bleaching, reduces calcification, increases susceptibility to pathogens, and allows endolithic fungi to perforate the skeleton creating a porous and anomalous growth of the skeleton. Consequently, we suggest that the frequency of skeletal growth anomalies is expected to increase with the frequency of coral bleaching.     

Patterns in the geographic ranges of the world's woodpeckers

We used data on the world's woodpeckers to test for patterns in the geographic distributions of a single group of closely related species. The frequency distribution of woodpecker geographic range sizes is approximately lognormal. Most variation in range sizes is explained by differences between species within genera; that is, range size seems to be an evolutionarily labile trait. The largest woodpecker ranges are found in Eurasia, both when absolute differences are compared and when range size is measured as a proportion of estimated available habitat. Notably, there is a negative relationship between the mean range sizes attained by species in a genus or tribe in South America and the mean ranges attained by species in the same tribe or genus in North America. Large-bodied species tend to be more widely distributed and to live at higher latitudes, but both tendencies disappear if the taxonomic relatedness of species is controlled for. Species living at high latitudes also tend to be more widely distributed. This relationship seems largely due to the effect of North American woodpeckers, which show it even when the taxonomic relatedness of species is controlled. Small continents generally have more woodpecker species than do large ones. Woodpecker geographic range sizes are smaller the more woodpecker species inhabit an area. Species show less overlap in their geographic ranges with species of similar than with species of dissimilar body size. The implications of these results for our understanding of patterns in geographic range sizes are discussed.     

The whole mitochondrial genome sequence of the zebra finch (Taeniopygia guttata)

Here we describe the complete nucleotide sequence of the mitochondrial genome (16 583/4 bp) of the zebra finch (Taeniopygia guttata). Primers were designed based on highly conserved regions of an alignment of three passerine complete mitochondrial DNA (mtDNA) sequences. A combination of overlapping long polymerase chain reaction (PCR) purification, followed by fully nested PCR and sequencing was used to determine the complete mtDNA genome. Six birds, from distinct maternal lineages of a pedigreed population were sequenced. Five novel haplotypes were identified. These sequences provide the first data for sequence variation across the whole mitochondrial genome of a passerine bird species.     

Larval food composition affects courtship song and sperm expenditure in a lekking moth

1. Variation in larval food composition can have far‐reaching effects on the adult phenotype of insects. To maximise reproductive output, it is therefore beneficial if insects are able to plastically adapt to nutritional cues in their larval diet. 2. The expression of sexual traits implicated in pre‐ and postcopulatory sexual selection of the lesser wax moth, Achroia grisella Fabricius, across different rearing environments of varying diet composition was investigated. 3. Moths reared on diet with relatively low amounts of carbohydrate, but more protein and fats, had lower survival rates, decreased body mass, and longer development times. Males reared on this diet produced songs with higher pulse pair rates (which are attractive to females) and transferred more sperm per copulation than males reared on the alternative diets. 4. There was no evidence for a trade‐off between pre‐ and postcopulatory traits. Interestingly, individuals with both higher pulse pair rates and more transferred sperm came from the treatment group with higher mortality rates and generally poorer development. The present results suggest that both of these sexual characteristics are developmentally plastic, but that only moths reared on the protein‐rich diet were able to benefit from this plasticity.     

Carbon dioxide,methane, and nitrous oxide exchanges in an age‐sequence of temperate pine forests

We investigated soil carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) exchanges in an age‐sequence (4, 17, 32, 67 years old) of eastern white pine (Pinus strobus L.) forests in southern Ontario, Canada, for the period of mid‐April to mid‐December in 2006 and 2007. For both CH₄ and N₂O, we observed uptake and emission ranging from ?160 to 245 μg CH₄ m^?2 h^?1 and ?52 to 21 μg N₂O m^?2 h^?1, respectively (negative values indicate uptake). Mean fluxes from mid‐April to mid‐December across the 4, 17, 32, 67 years old stands were similar for CO₂ fluxes (259, 246, 220, and 250 mg CO₂ m^?2 h^?1, respectively), without pattern for N₂O fluxes (?3.7, 1.5, ?2.2, and ?7.6 μg N₂O m^?2 h^?1, respectively), whereas the uptake rates of CH₄ increased with stand age (6.4, ?7.9, ?10.8, and ?23.3 μg CH₄ m^?2 h^?1, respectively). For the same period, the combined contribution of CH₄ and N₂O exchanges to the global warming potential (GWP) calculated from net ecosystem exchange of CO₂ and aggregated soil exchanges of CH₄ and N₂O was on average 4%, <1%, <1%, and 2% for the 4, 17, 32, 67 years old stand, respectively. Soil CO₂ fluxes correlated positively with soil temperature but had no relationship with soil moisture. We found no control of soil temperature or soil moisture on CH₄ and N₂O fluxes, but CH₄ emission was observed following summer rainfall events. LFH layer removal reduced CO₂ emissions by 43%, increased CH₄ uptake during dry and warm soil conditions by more than twofold, but did not affect N₂O flux. We suggest that significant alternating sink and source potentials for both CH₄ and N₂O may occur in N‐ and soil water‐limited forest ecosystems, which constitute a large portion of forest cover in temperate areas.     

Are local weather,NDVI and NAO consistent determinants of red deer weight across three contrasting European countries?

There are multiple paths via which environmental variation can impact herbivore ecology and this makes the identification of drivers challenging. Researchers have used diverse approaches to describe the association between environmental variation and ecology, including local weather, large-scale patterns of climate, and satellite imagery reflecting plant productivity and phenology. However, it is unclear to what extent it is possible to find a single measure that captures climatic effects over broad spatial scales. There may, in fact, be no a priori reason to expect populations of the same species living in different areas to respond in the same way to climate as their population may experience limiting factors at different times of the year, and the forms of regulation may differ among populations. Here, we examine whether the same environmental indices [seasonal Real Bioclimatic Index (RBI), seasonal Normalized Difference Vegetation Index (NDVI) and winter North Atlantic Oscillation (NAO)] influence body size in different populations of a large ungulate living in Mediterranean Spain, Western Scotland and Norway. We found substantial differences in the pattern of weight change over time in adult female red deer among study areas as well as different environmental drivers associated with variation in weight. The lack of general patterns for a given species at a continental scale suggest that detailed knowledge regarding the way climate affects local populations is often necessary to successfully predict climate impact. We caution against extrapolation of results from localized climate–population studies to broad spatial scales.