"Drink Milk for Fitness": The Cultural Politics of Human Biological Variation and Milk Consumption in the United States

Cow's milk is accorded a high cultural value in the contemporary United States. Its white color, association with the maternal and the pastoral, and repeated mention in the Bible add positive symbolic weight to this major national agricultural commodity. Thus, it comes as no surprise that influential policy-making institutions in the United States recommend milk consumption for all U.S. groups. This is despite variation in adult populations' abilities to digest milk, which has been documented by biological anthropologists. This article assesses various U.S. "stories" about milk consumption and its relationship to biological variation against the biological anthropological explanation of variation in lactase activity/lactose tolerance. Many of these serve as normalizing discourses that ultimately pathologize biological difference and may undermine the dietary traditions of some ethnic groups. In particular, the close relationship between government and the dairy industry leads to policies that fail to seriously consider variation in digestive physiology among the diverse U.S. populations.     

The radiation of red colobus monkeys (Primates,Colobinae): morphological evolution in a clade of endangered African primates

Red colobus monkeys are a group of African monkeys that include some of the most endangered primate populations. Despite urgently needing to understand the importance of particular populations for preserving the biodiversity of this lineage, their evolutionary relationships remain poorly understood, and their taxonomy is unstable, and often enigmatic. Data on behaviour, ecology, genetics, and morphology are thus strongly needed to address taxonomic issues that are not only relevant for primatologists, but also for conservation biologists. In this study, we investigated the morphological diversity and evolution of red colobus by examining the cranial variation of 369 individuals from most living populations. Crania were measured using a set of 64 anatomical landmarks, and were analysed using geometric morphometric methods for the study of three‐dimensional landmark coordinates. We found significant differences among most of the populations traditionally described on the basis of pelage colour and geographic distribution. However, differences tended to be smaller within biogeographic assemblages, which might be related to mountain refugia during periods of forest contraction in the Pleistocene.We also found a tendency towards large taxonomic distances, which suggested that populations might have originated earlier than has been traditionally thought, a result congruent with a recent molecular phylogenetic analysis. However, the distinctive forms of East African relict populations might be related to an acceleration of morphological evolution in small peripheral isolates, under strong selective pressures. This indicates that small and isolated populations, which are also the most endangered ones, might indeed be unique representatives of the red colobus radiation, and hence contribute to its biodiversity significantly. However, in‐ depth morphological studies of red colobus, particularly those in peripheral populations that tend to be rare in the wild, as well as in museum collections, is hampered by a paucity of data. In these cases, populations might be extinct before primatologists and conservationsts can even appreciate what was lost.     

Small and impoverished regional species pools constrain colonisation of restored river reaches by fishes

1. Using an extensive data set from 18 river restoration projects in the lower mountain ranges of Germany and 5462 river reaches in their surroundings, we estimated the spatial extent of the regional fish species pool from which restored river reaches are colonised. 2. Restoration resulted in a marginally significant increase in fish species richness; however, restored reaches still deviated markedly from natural reference conditions. Nearly all (96.6%) species occurring in restored reaches were present in reaches within a distance of 5 km up‐ or downstream of the restored reach. 3. Species richness in restored reaches was correlated with species richness within a 5‐km species pool. This relationship was more pronounced for common than for rare fishes and applied to both the total number of fish species at the restored reach and the number of additional fish species that were not present at unrestored conditions. 4. The richness of the regional species pools was greatly impoverished. On average, only 50% of all species considered to represent natural reference assemblages were present. The limited success in establishing natural fish assemblages in restored reaches was attributed to spatial limitation (e.g. due to fragmentation) and an impoverished regional species pools from which restored reaches recruit. 5. We recommend that integrated river restoration management should consider not only the abiotic prerequisites of successful restorations, but also the structure and quality of the regional species pool.     

Effects of colony size on larval performance in a processionary moth

1. Some lepidopteran species have larvae that live gregariously, especially in early instars. Colony‐living species may benefit from improved protection from predators, thermoregulation, and feeding facilitation, for example. 2. While many studies have compared solitary and gregarious life styles, few data exist as to the relationship between size of the larval colony and larval performance in gregarious species. The present study was aimed at understanding the importance of colony size for growth and survival of the northern pine processionary moth (Thaumetopoea pinivora) larvae. 3. Field studies, comparing three different sizes of colonies of T. pinivora larvae, showed that individuals in larger colonies had a higher survival rate compared with those living in smaller colonies and also a faster growth rate. 4. The higher survival rate of large colonies was attributed to improved protection from predacious arthropods. 5. In early spring, the young larvae bask in the sun to increase their body temperature. In field experiments the thermal gain was higher in large colonies, and individuals in such colonies also grew faster. As growth rate was not affected by colony size when the ability to bask was experimentally removed in a laboratory experiment, the higher growth rate of the larger colonies was probably due to improved thermoregulation rather than feeding facilitation. 6. The size of larval colonies of gregarious insects depends on natural mortality events as well as on female oviposition strategy. Our results show that decreasing colony size can lead to a reduction in growth rate and survival. It is therefore important to understand whether or not small colonies will benefit equally from the gregarious behaviour.     

Reciprocal trophic niche shifts in native and invasive fish: salmonids and galaxiids in Patagonian lakes

1. Rainbow (Oncorhynchus mykiss) and brown trout (Salmo trutta) are widespread and invasive salmonids with important lethal effects as predators, although indirect effects are also possible. We used stable isotope analyses (δ¹⁵N, δ¹³C) to explore how the density of invasive trout in 25 Patagonian lakes alters the trophic niche (TN) of a widespread native fish, Galaxias platei (Galaxiidae). We also explored how the density of the galaxiid influences the TN of invasive trout. 2. We quantified two aspects of the TN: (i) the proportion of littoral carbon (PL) and (ii) trophic height (TH) (i.e. the ‘height’ at which the fish feeds in the food web). We related these measures of TN in a given species to the density of other species (as estimated by catch‐per‐unit‐effort). 3. As G. platei body size increased, their PL increased (increasing littoral feeding) in several lakes. However, none of the fish species investigated showed changes in PL with increasing density of the other fish species. TH increased with body size in all three species. In addition, the TH of large G. platei declined with increasing trout density and, reciprocally, the TH of large S. trutta decreased with decreasing G. platei density. 4. The reciprocal effects of native and the invasive fish on TH were as large as a shift of one trophic level. This pattern is consistent with an exhaustion of galaxiid prey for both piscivorous G. platei and S. trutta in lakes with high trout density. 5. These finding support the suggested management strategy of culling trout from overpopulated lakes, which should simultaneously protect native fish and enhance a lucrative sport fishery for large trout.     

Number of individuals and molecular markers to use in genetic differentiation studies

Molecular markers are frequently used to study genetic variation among individuals within or between populations. Differences in marker banding patterns can be used to verify if individuals do, or do not, represent distinct groups or populations. Only in 2005, more than 500 studies used molecular markers to group individuals in clusters. Such studies make use of an arbitrary number of molecular markers from each of an arbitrary number of individuals presumed to represent distinct genotypes. However, the greater the genetic variation, the more likely a larger number of individuals and markers will be needed to capture a population's genetic signature. The numbers of both, markers and individuals included thus affect the way in which individuals are organized through cluster analyses, thereby affecting the conclusions drawn. Here we present a method that provides statistical criteria to verify that individual and marker sample sizes are sufficient to accurately depict genetic differentiation among different populations. Our method uses a resampling technique to assess the reproducibility of obtaining a particular grouping pattern for specific data sets. It thus, allows to estimate the robustness of the results obtained without including additional individuals, or markers.     

Tackling the taxonomic impediment: a global assessment for ant‐nest beetle diversity (Coleoptera: Carabidae: Paussini)

We evaluated the completeness and historical trends of the taxonomic knowledge of the myrmecophilous ground beetle tribe Paussini (Coleoptera, Carabidae, Paussinae). Species accumulation curves were modelled using a logistic function. Similar analyses were conducted for genera and subgenera. Although not all biogeographical regions have been equally explored, accumulation curves reached a plateau in all cases. Our models predict that about 96% of the world fauna has been already described. However, the asymptotes calculated for the Australian and Oriental species should be interpreted as false plateaus because of the lack of recent research. Similarly, patterns of genera accumulation indicate that a plateau has been reached. As a result of continued debate on the use and validity of Paussini subgenera, the accumulation curves of subgenera showed stepped patterns, with no evidence of plateaus. Thus, although relatively few species are expected to be described in the future, the species accumulation curves indicate that the taxonomic inventory is not yet complete. Differences in accumulation patterns among biogeographical regions can be used to highlight the areas where more species are expected, and hence where taxonomical efforts should be concentrated. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 330–339.     

Mobility and Persistence of Petroleum Hydrocarbons in Peat Soils of Southeastern Mexico

Spilled crude petroleum from oil wells contains numerous hydrocarbons, some of which are toxic and threaten life. We have studied the mobility and persistence of hydrocarbons in waterlogged soils that contain large proportions of fermented organic matter (Histosols) and large concentrations of dissolved organic carbon (DOC) in the State of Tabasco, Mexico. We sampled soil and phreatic water at sites polluted by oil spills for several decades, as well as at sites that had only recently (few weeks) been polluted, and compared their hydrocarbon contents with those of unaffected sites in the same area. Samples were analyzed for 16 non-alkylated polyaromatic hydrocarbons (PAHs) and n-alkanes from nC9 to nC34. The spilled hydrocarbons had remained predominantly in the organic surface horizons of the soil where spillage occurred; there was little evidence of movement within the soil. The fraction of low molecular weight compounds was larger at sites of recent spills than where spills happened several decades ago. Nevertheless, sites of old spills still contained large concentrations of hydrocarbons, among which those of low molecular weight represented from 30 to 49% of total PAHs and from 50 to 84% of total n-alkanes, indicating that volatilization or microbial degradation is slow in these soils. In the peat horizons the measured organic carbon partition coefficients (K _oc ) for the higher molecular weight PAHs were consistently smaller than those estimated by empirical equations by up to two orders of magnitude. The dissolved organic carbon of these peat soils seems to influence this behavior. At sites of old spills, partition coefficients for the PAHs were larger than at sites of recent spills.