Harder,better, faster,stronger: Weapon size is more sexually dimorphic than weapon biomechanical components in two freshwater anomuran species

Sexual selection influences the evolution of morphological traits that increase the likelihood of monopolizing scarce resources. When such traits are used during contests, they are termed weapons. Given that resources are typically linked to monopolizing mating partners, theory expects only males to bear weapons. In some species, however, females also bear weapons, although typically smaller than male weapons. Understanding why females bear smaller weapons can thus help us understand the selective pressures behind weapon evolution. However, most of our knowledge comes from studies on weapon size, while the biomechanics of weapons, such as the size of the muscles, efficiency, and shape are seldom studied. Our goal was to test if the theoretical expectations for weapon size sexual dimorphism also occur for weapon biomechanics using two aeglid crab species. Males of both species had larger claws which were also stronger than female claws. Male claws were also more efficient than females' claws (although we used only one species in this analysis). For weapon shape, though, only one species differed in the mean claw shape. Regarding scaling differences, in both species, male claws had higher size scaling than females, while only one species had a higher shape scaling. However, male weapons did not have higher scaling regarding strength and efficiency than females. Thus, males apparently allocate more resources in weapons than females, but once allocated, muscle and efficiency follow a similar developmental pathway in both sexes. Taken together, our results show that sexual dimorphism in weapons involves more than differences in size. Shape differences are especially intriguing because we cannot fully understand its causes. Yet, we highlight that such subtle differences can only be detected by measuring and analysing weapon shape and biomechanical components. Only then we might better understand how weapons are forged.     

Simultaneous Isolation of Three Different Stem Cell Populations from Murine Skin

The skin is a rich source of readily accessible stem cells. The level of plasticity afforded by these cells is becoming increasingly important as the potential of stem cells in Cell Therapy and Regenerative Medicine continues to be explored. Several protocols described single type stem cell isolation from skin; however, none of them afforded simultaneous isolation of more than one population. Herein, we describe the simultaneous isolation and characterization of three stem cell populations from the dermis and epidermis of murine skin, namely Epidermal Stem Cells (EpiSCs), Skin-derived Precursors (SKPs) and Mesenchymal Stem Cells (MSCs). The simultaneous isolation was possible through a simple protocol based on culture selection techniques. These cell populations are shown to be capable of generating chondrocytes, adipocytes, osteocytes, terminally differentiated keratinocytes, neurons and glia, rendering this protocol suitable for the isolation of cells for tissue replenishment and cell based therapies. The advantages of this procedure are far-reaching since the skin is not only the largest organ in the body, but also provides an easily accessible source of stem cells for autologous graft.     

The Distribution of Coumarins and Furanocoumarins in Citrus Species Closely Matches Citrus Phylogeny and Reflects the Organization of Biosynthetic Pathways

Citrus plants are able to produce defense compounds such as coumarins and furanocoumarins to cope with herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitizers and can interact with medications, leading to the “grapefruit juice effect”. Removing coumarins and furanocoumarins from food and cosmetics imply additional costs and might alter product quality. Thus, the selection of Citrus cultivars displaying low coumarin and furanocoumarin contents constitutes a valuable alternative. In this study, we performed ultra-performance liquid chromatography coupled with mass spectrometry analyses to determine the contents of these compounds within the peel and the pulp of 61 Citrus species representative of the genetic diversity all Citrus. Generally, Citrus peel contains larger diversity and higher concentrations of coumarin/furanocoumarin than the pulp of the same fruits. According to the chemotypes found in the peel, Citrus species can be separated into 4 groups that correspond to the 4 ancestral taxa (pummelos, mandarins, citrons and papedas) and extended with their respective secondary species descendants. Three of the 4 ancestral taxa (pummelos, citrons and papedas) synthesize high amounts of these compounds, whereas mandarins appear practically devoid of them. Additionally, all ancestral taxa and their hybrids are logically organized according to the coumarin and furanocoumarin pathways described in the literature. This organization allows hypotheses to be drawn regarding the biosynthetic origin of compounds for which the biogenesis remains unresolved. Determining coumarin and furanocoumarin contents is also helpful for hypothesizing the origin of Citrus species for which the phylogeny is presently not firmly established. Finally, this work also notes favorable hybridization schemes that will lead to low coumarin and furanocoumarin contents, and we propose to select mandarins and Ichang papeda as Citrus varieties for use in creating species devoid of these toxic compounds in future breeding programs.     

A multimetric index based on benthic macroinvertebrates for evaluation of Atlantic Forest streams at Rio de Janeiro State, Brazil

This study describes the application of a protocol for biological assessment of water quality at first to third order streams at Serra dos órg?os, an area covered by Atlantic Forest in Rio de Janeiro State, Brazil. Major impacts in the region are domestic effluents and deforestation. Our main objective is to establish biocriteria for the establishment of the Serra dos órg?os Multimetric Index (SOMI) based on benthic macroinvertebrates. We used data from previous studies, sampled by experienced biologists, from 1999 through 2002. The benthic macroinvertebrate community was sampled in 12 reference sites and seven impaired sites in three river basins: Guapimirim, Macaé and Grande, all from the same bioregion. From the 22 tested metrics, 6 were included in the SOMI (% Diptera, % Coleoptera, Family Taxa, EPT Taxa, BMWP-CETEC and % Shredders). Scores (5, 3 or 1) were developed for these metrics to allow for aggregation into the index. Seven intermediately impaired sites were used for evaluating the applicability of the multimetric index. We concluded that the SOMI is a robust easy-to-apply tool for biomonitoring programs in the Serra dos órg?os region, south-east Brazil. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorised users. Handling editor: D. Dudgeon     

Influence of rainfall on sleeping site choice by a group of anubis baboons (Papio anubis)

For diurnal nonhuman primates, shifting among different sleeping sites may provide multiple benefits such as better protection from predators, reduced risk of parasitic infection, and closer proximity to spatially and temporally heterogeneous food and water. This last benefit may be particularly important in sleeping site selection by primates living in savanna‐woodlands where rainfall is more limited and more seasonally pronounced than in rainforests. Here, we examined the influence of rainfall, a factor that affects food and water availability, on the use of sleeping sites by anubis baboons (Papio anubis) over two 13‐month study periods that differed in rainfall patterns. We predicted that during wet periods, when food and water availability should be higher, the study group would limit the number of sleeping sites and would stay at each one for more consecutive nights than during dry periods. Conversely, we predicted that during dry periods the group would increase the number of sleeping sites and stay at each one for fewer consecutive nights as they searched more widely for food and water. We also predicted that the group would more often choose sleeping sites closer to the center of the area used during daytime (between 07:00 and 19:00) during wet months than during dry months. Using Global Positioning System data from collared individuals, we found that our first prediction was not supported on either monthly or yearly timescales, although past monthly rainfall predicted the use of the main sleeping site in the second study period. Our second prediction was supported only on a yearly timescale. This study suggests that baboons’ choice of sleeping sites is fluid over time while being sensitive to local environmental conditions, one of which may be rainfall.     

Species limits in butterflies (Lepidoptera: Nymphalidae): reconciling classical taxonomy with the multispecies coalescent

Species delimitation is at the core of biological sciences. During the last decade, molecular‐based approaches have advanced the field by providing additional sources of evidence to classical, morphology‐based taxonomy. However, taxonomy has not yet fully embraced molecular species delimitation beyond threshold‐based, single‐gene approaches, and taxonomic knowledge is not commonly integrated into multilocus species delimitation models. Here we aim to bridge empirical data (taxonomic and genetic) with recently developed coalescent‐based species delimitation approaches. We use the multispecies coalescent model as implemented in two Bayesian methods (dissect/stacey and bp&p ) to infer species hypotheses. In both cases, we account for phylogenetic uncertainty (by not using any guide tree) and taxonomic uncertainty (by measuring the impact of using a priori taxonomic assignments to specimens). We focus on an entire Neotropical tribe of butterflies, the Haeterini (Nymphalidae: Satyrinae). We contrast divergent taxonomic opinion – splitting, lumping and misclassifying species – in the light of different phenotypic classifications proposed to date. Our results provide a solid background for the recognition of 22 species. The synergistic approach presented here overcomes limitations in both traditional taxonomy (e.g. by recognizing cryptic species) and molecular‐based methods (e.g. by recognizing structured populations, and not raising them to species). Our framework provides a step forward towards standardization and increasing reproducibility of species delimitations.