The phylogenetic relationships of the shags and cormorants: can sequence data resolve a disagreement between behavior and morphology?

Taxonomic arrangements for the cormorants and shags (Phalacrocoracidae) had varied greatly until two quite similar arrangements, one based on behavior and the other on osteological characters, became the basis for current thought on the evolutionary relationships of these birds. The terms cormorant and shag, which had previously been haphazardly applied to members of the group, became the vernacular terms for the two major subdivisions within this family. The two taxonomies differ in places, however, with the behavioral taxonomy placing several species within the shags and the osteological taxonomy and phylogeny grouping those species (as the marine cormorants) and placing them within the cormorants. In an attempt to resolve the differences in the relationships hypothesized by behavior and morphology, we sequenced three mitochondrial genes (12S, ATPase 6, and ATPase 8). Initial equally weighted parsimony trees differed slightly from our two weighted parsimony trees, one of which was also our maximum-likelihood tree. Many of the branches within our trees were well supported, but some sections of the phylogeny proved difficult to resolve with confidence. Our sequence trees differ substantially from the morphological phylogeny and show that neither the shags nor the cormorants are monophyletic, but form an intermingled group. Some of the groups supported by both the behavioral and the morphological taxonomies (e.g., the cliff shags, Stictocarbo) appear to be polyphyletic. Conversely, the monophyly of the blue-eyed shags, a traditional group that the osteological analysis had found to be paraphyletic, was supported by the sequence data. Until more taxa are sampled and a fully robust phylogeny is obtained, a conservative approach accepting a single genus, Phalacrocorax, for the shags and cormorants is recommended.     

Does the match between individual and group behavior matter in shoaling sticklebacks?

In animals living in groups, the social environment is fundamental to shaping the behaviors and life histories of an individual. A mismatch between individual and group behavior patterns may have disadvantages if the individual is incapable of flexibly changing its state in response to the social environment that influences its energy gain and expenditure. We used different social groups of juvenile three‐spined sticklebacks (Gasterosteus aculeatus) with experimentally manipulated compositions of individual sociability to study the feedback between individual and group behaviors and to test how the social environment shapes behavior, metabolic rate, and growth. Experimentally created unsociable groups, containing a high proportion of less sociable fish, showed bolder collective behaviors during feeding than did corresponding sociable groups. Fish within groups where the majority of members had a level of sociability similar to their own gained more mass than did those within mismatched groups. Less sociable individuals within sociable groups tended to have a relatively low mass but a high standard metabolic rate. A mismatch between the sociability of an individual and that of the majority of the group in which it is living confers a growth disadvantage probably due to the expression of nonadaptive behaviors that increase energetic costs.     

Morphology, sociality, and ecology: can morphology predict pairing behavior in coral reef fishes?

Morphology can contain valuable information about the ecological performance of reef fishes, but it has rarely been used in combination with social traits. Social behavior is known to influence the ecological role of fishes; however, the ecological basis for pairing in reef fishes is not well understood. Field observations of 2,753 individuals, in 47 species in six families of biting reef fishes (Acanthuridae, Chaetodontidae, Kyphosidae, Labridae, Pomacanthidae, Siganidae), were used in combination with six morphological measurements, to examine the morphology of fishes in different social systems. A principal components analysis of morphological traits segregated species with high proportions of pairing individuals from non-pairing species along principal component 1, explaining 40.8 % of the variation. Pairing species were characterized by large eyes, concave foreheads, pointed snouts, deep bodies, and small maximum sizes. There was a significant positive relationship between these morphological traits (i.e., scores on PC1) and the prevalence of pairing within the Chaetodontidae (r ² = 0.59; P = 0.026), Siganidae (r ² = 0.72; P = 0.004), and Acanthuridae (r ² = 0.82; P < 0.001). This was consistent when traits were corrected for phylogenetic effects. No pattern was evident in the scarine Labridae (r ² = 0.15; P = 0.17). The morphological characteristics found among pairing species suggest that pairing species share common ecological traits, including foraging for small prey items in micro-topographically complex environments such as reef crevices. These ecological traits may have played a role in the evolution of pairing behavior and subsequently led to the development of reproductive patterns based on monogamy.     

Pollination syndromes in a specialised plant‐pollinator interaction: does floral morphology predict pollinators in Calceolaria?

Pollination syndromes are defined as suites of floral traits evolved in response to selection imposed by a particular group of pollinators (e.g., butterflies, hummingbirds, bats). Although numerous studies demonstrated their occurrence in plants pollinated by radically different pollinators, it is less known whether it is possible to identify them within species pollinated by one functional pollinator group. In such a framework, we expect floral traits to evolve also in response to pollinator subgroups (e.g., species, genera) within that unique functional group. On this, specialised pollination systems represent appropriate case studies to test such expectations. Calceolaria is a highly diversified plant genus pollinated by oil‐collecting bees in genera Centris and Chalepogenus. Variation in floral traits in Calceolaria has recently been suggested to reflect adaptations to pollinator types. However, to date no study has explicitly tested that observation. In this paper, we quantitatively test that hypothesis by evaluating the presence of pollination syndromes within the specialised pollination system formed by several Calceolaria and their insect pollinators. To do so, we use multivariate approaches and explore the structural matching between the morphology of 10 Calceolaria taxa and that of their principal pollinators. Our results identify morphological matching between floral traits related to access to the reward and insect traits involved in oil collection, confirming the presence of pollinator syndromes in Calceolaria. From a general perspective, our findings indicate that the pollination syndrome concept can be also extended to the intra‐pollinator group level.     

Does the relationship between offspring size and performance change across the life‐history?

What selection pressures drive the evolution of offspring size? Answering this fundamental question for any species requires an understanding of the relationship between offspring size and offspring fitness. A major goal of evolutionary ecologists has been to estimate this critical relationship, but for organisms with complex lifecycles, logistical constraints restrict most studies to early life‐history stages only. Here, we examine the relationship between offspring size and offspring performance in the field across multiple life‐history stages and across generations in a marine invertebrate .We then use these data to parameterise a simple optimality model to generate predictions of optimal offspring size and determined whether these predictions depended on which estimate of offspring performance was used. We found that offspring size had consistently positive effects on performance (estimated as post‐metamorphic growth, fecundity and reproductive output). We also found that manipulating the experience of offspring during the larval phase changed the way in which offspring size affects performance: offspring size affected post‐metamorphic growth when larvae were allowed to settle immediately but offspring size affected survival when larvae were forced to swim prior to settlement. Despite finding consistently positive effects of offspring size, early measures of the effect of offspring size resulted in the systematic underestimation of optimal offspring size. Surprisingly, the amount of variation in offspring performance that offspring size explained decreased with increasing time in the field but the steepness of the relationship between offspring size and performance actually increased. Our results suggest caution should be exercised when empirically examining offspring size effects – it may not be appropriate to assume that early measures are a good reflection of the actual relationship between offspring size and fitness.     

Long‐distance dispersal or postglacial contraction? Insights into disjunction between Himalaya–Hengduan Mountains and Taiwan in a cold‐adapted herbaceous genus,Triplostegia

Current disjunct patterns can result from long‐distance dispersal or postglacial contraction. We herein investigate the evolutionary history of Triplostegia to elucidate the disjunction between the Himalaya–Hengduan Mountain region (HHM) and Taiwan (TW). Genetic structure of Triplostegia was investigated for 48 populations using sequences from five chloroplast loci and the ribosomal nuclear internal transcribed spacer. Divergence time estimation, ancestral area reconstruction, and species distribution modeling (SDM) were employed to examine the biogeographic history of Triplostegia. Substantial genetic differentiation among populations from southwestern China (SW), Central China (CC), and TW was detected. Triplostegia was inferred to have originated in SW, and diversification began during the late Miocene; CC was colonized in the mid‐Pliocene, and TW was finally colonized in the early Pleistocene. SDM suggested an expansion of climatically suitable areas during the Last Glacial Maximum and range contraction during the Last interglacial in Triplostegia. Disjunction between HHM and TW in Triplostegia is most likely the consequence of topographic isolation and postglacial contraction. The potential climatic suitability areas for Triplostegia by 2070s (2061–2080) are predicted to slightly shrink and move northward. With continued global warming and human‐induced deforestation, extinction risk may increase for the cold‐adapted species, and appropriate strategies should be employed for ecosystem conservation.     

Built to bite? Differences in cranial morphology and bite performance between narrow‐ and broad‐headed European glass eels

The presence of two phenotypes in a single species is a widespread phenomenon, also observed in European eel (Anguilla anguilla). This dimorphism has been related to dietary differences in the subadult elver and yellow eel stages, with broad‐heads generally feeding on harder and/or larger‐bodied prey items than narrow‐heads. Nevertheless, both broad‐ and narrow‐headed phenotypes can already be found among glass eels, the stage preceding the elver eel stage. As these glass eels are considered nonfeeding, we investigate here to what degree the observed variation in head width is reflected in variation in the musculoskeletal feeding system, as well as whether this reflects the same variation observed in the older, dimorphic yellow eels. Additionally, we investigate whether musculoskeletal differences between broad‐ and narrow‐headed glass eels have implications on their feeding performance and could thus impact prey preference when eels start feeding. Therefore, we compared the cranial musculoskeletal system of five broad‐ and narrow‐headed glass eels using 3D‐reconstructions and simulated the glass eel's bite force using the data of the muscle reconstructions. We found that the variation in the musculoskeletal system of glass eels indeed reflects that of the yellow eels. Broader heads were related to larger jaw muscles, responsible for mouth closure. Accordingly, broad‐heads could generate higher bite forces than narrow‐headed glass eels. In addition, broader heads were associated with higher coronoid processes and shorter hyomandibulae, beneficial for dealing with higher mechanical loadings and consequently, harder prey. We, thus, show that head width variation in glass eels is related to musculoskeletal differences which, in turn, can affect feeding performance. As such, differences in prey preference can already take place the moment the eels start feeding, potentially leading to the dimorphism observed in the elver and yellow eel stage.     

Who needs a forelimb anyway? Locomotor,postural and manipulative behavior in a one‐armed gibbon

Given the predominance of brachiation and other forms of suspension in gibbon locomotion, we compared the locomotor, postural, and manipulative behaviors of a captive, juvenile, one‐armed gibbon to the behavioral profiles of his family members. We expected Kien Nahn, whose arm was amputated in response to an untreatable injury approximately 1 year before observations began, to avoid suspensory locomotion, to spend more time immobile, and to be less likely to exhibit postures involving forelimb suspension. Data were collected using scan sampling to record the behaviors and postures of Kien Nahn, his younger brother, and his parents. Additional postural and manipulative behaviors were recorded ad lib. Kien Nahn and his younger sibling had similar activity levels, and although differences in postural profiles existed, they were surprisingly few. Specifically, Kien Nahn spent significantly less time in motion and in non‐suspensory forms of locomotion than his brother. When compared to his parents, Kien Nahn was found to be both active and in motion more often, but was less likely to exhibit the forelimb suspension posture. Despite the increased energetic demands associated with one‐armed brachiation, Kien Nahn preferred suspensory locomotion to other forms of locomotion. Furthermore, he found unique solutions for foraging and locomoting, often making use of his feet and teeth, and he was generally the first to approach and manipulate enrichment objects. We found no evidence to suggest that Kien Nahn's injury has altered his activity levels. Although the one‐armed gibbon displayed slightly different locomotor, postural, and manipulative behaviors than his family members, he seems to have adapted well to his injury. Zoo Biol 0:1–8, 2007. © 2007 Wiley‐Liss, Inc.     

Does the disturbance hypothesis explain the biomass increase in basin‐wide Amazon forest plot data?

Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential–power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change.     

European earthstars in Geastraceae (Geastrales,Phallomycetidae) – a systematic approach using morphology and molecular sequence data

Abstract

Phylogenetic relationships among European earthstars were inferred using sequence data from the nuclear ribosomal DNA internal transcribed region (ITS1, 5.8S and ITS2), partial nuclear large subunit (LSU), and partial translation elongation factor 1-alpha (Tef-α). The phylogenetic analyses recovered 11 clades that correlate to 31 morphological species and species groups. A close relationship of Myriostoma coliforme and Geastrum was supported by the molecular data. The genus Radiigera was found to be polyphyletic, and the four species were recovered in different clades within Geastrum. Radiigera bushnellii, R. flexuosa, R. fuscogleba and R. taylori are therefore combined in Geastrum. One of the supported terminal clades is likely to represent an undescribed species that occurs in east central Europe. Notes on the morphology and ecology for each species are given, including a key to the 31 species of earthstars occurring in Europe.     

Physiological performance and mating system in Clarkia (Onagraceae): Does phenotypic selection predict divergence between sister species?

? Premise of the study: The evolution of self-fertilization often occurs in association with other floral, life history, and fitness-related traits. A previous study found that field populations of Clarkia exilis (a predominantly autogamous selfer) and its sister species, Clarkia unguiculata (a facultative outcrosser) differ in mean photosynthetic rates and instantaneous water use efficiency (WUE(i)). Here, we investigate the strength and direction of selection on these traits in multiple populations of each taxon to determine whether natural selection may contribute to the phenotypic differences between them. ? Methods: In spring 2008, we measured instantaneous gas exchange rates in nine populations during vegetative growth (Early) and/or during flowering (Late). We conducted selection gradient analyses and estimated selection differentials within populations and across pooled conspecific populations to evaluate the strength, direction, and consistency of selection on each trait early and late in the season. ? Key results: The direction and relative strength of selection on photosynthetic rates in these taxa corresponds to the phenotypic difference between them; C. exilis has higher photosynthetic rates than C. unguiculata, as well as stronger, more consistent selection favoring rapid photosynthesis throughout the growing season. Patterns of selection on transpiration, WUE(i), and the timing of flowering progression are less consistent with phenotypic differences (or lack thereof) between taxa. ? Conclusions: We detected several examples where selection was consistent with the phenotypic divergence between sister taxa, but there were also numerous instances that were equivocal or in which selection did not predict the realized phenotypic difference between taxa.     

Does a relationship exist between the urate pool in the body and lipid peroxidation during exercise?

In this study, we investigated whether a relationship exists between the levels of urate in vivo and lipid peroxidation during exercise. Seven healthy male subjects performed exhaustive cycling exercise under the following three conditions. The levels of urate, thiobarbituric acid reactive substances (TBARS) and allantoin in plasma and urine were examined before exercise and during a 3h recovery period. (1) Benzbromarone administration experiment: benzbromarone (an uricosuric agent) was administered orally the day before exercise. (2) IMP administration experiment: inosine 5'-monophosphate disodium salt (a precursor of urate) was administered orally the day before exercise. (3) Control experiment: no test substance was administered. The main results obtained were as follows. Plasma urate levels and total peroxyl radical-trapping antioxidant parameter (TRAP) for deproteinized plasma in the resting period significantly decreased depending on the treatment, in the order of IMP> control > benzbromarone. A significant positive correlation was evident between plasma urate levels and TRAP values for deproteinized plasma. The increase in plasma levels of allantoin was observed only in the case of IMP treatment. A significant negative correlation between plasma levels of urate in the resting period and the amounts of urinary TBARS excreted during the recovery period was recognized. These results suggest that the urate level in vivo before exercise is a factor influencing lipid peroxidation during exhaustive exercise. Furthermore, these findings support the view that urate may serve as an important freeradical scavenger in vivo.     

Heterogeneity in recruitment and habitat patterns of valley oak (Quercus lobata Née) at the site and landscape scale in the Santa Monica Mountains, California, USA

Valley oak, Quercus lobata Née, has been a focus of conservation attention due to concerns about regeneration failure, habitat fragmentation and modification, and potential range contraction associated with climate change. A drawback of previous studies of valley oak stand structure and the regeneration problem has been their emphasis on one site or spatial and temporal scale. Generalization about valley oak dynamics from such studies is problematic because demographic parameters are not likely to be constant across sites, but heavily influenced by site-specific conditions. This study examines site-to-site variability across three locations in the Santa Monica Mountains National Recreation Area, California, USA. Variability in measures of stand structure and spatial pattern was examined across sites and within the landscape context. Estimates of expected landscape-scale evenness were derived by repeated random sampling of the data set and used as benchmarks for comparison with site-scale measures. Saplings were more abundant than expected at all three sites with sapling:adult ratios ranging from 0.5 to >1.0. Size-class structure suggested past recruitment problems at two sites, but recruitment at one site appears to have been steady for some time. Spatial distribution of adult stems at each site roughly corresponded to the estimated landscape pattern, but sapling establishment has shifted to north-to-east aspect hillsides and riparian-adjacent positions. In hilltop and swale habitats, adult valley oak are senescing without sapling recruitment. Shifting habitat-recruitment associations may lead to increasingly uneven distribution of stems across the landscape, altering landscape patterns and ecological processes.     

Does dietary supplementation with phytases affect the thermoregulatory and behavioral responses of pullets in a tropical environment?

Dietary supplementation of two types of phytases (fungal and bacterial) with different dosages (300 and 900 FTUs) was evaluated in the thermoregulatory and behavioral responses of replacement pullets in a tropical environment. 288 Hy-Line White laying birds with a mean weight of 639.60 ± 6.05 g, clinically healthy, and eight weeks old were used in the study. Respiratory rate (RR, breaths. min⁻¹), Cloacal temperature (CT, °C), Surface temperature with feathers (STWF, °C), and Surface temperature featherless (STF, °C) were measured in the morning and afternoon. Behavioral data were observed through the following activities: sitting, eating, drinking, exploring feathers (EF), non-aggressive pecking (NAP), and object pecking (OP) recorded every 10 min from 6 a.m. to 5 p.m. Environmental variables were measured along with thermoregulatory and behavioral responses. There was an interaction for RR between phytase and period of the day (P < 0.05). The lowest RR (morning) was observed in fungal phytase. STF and STWF were higher (P < 0.05) in the afternoon. Birds supplemented with fungal phytase showed lower STWF (P < 0.05). The variables that contributed to explain physiological and behavioral responses are shown in order of importance for (i) periods of day: morning (sitting, STWF, drinking, eating, and CT) and afternoon (STF, STWF, OP, drinking, eating, RR and sitting); (ii) phytases: fungal (STF, STWF, RR, sitting, eating and drinking); and bacterial (RR, STF, STWF, CT and sitting). Thermoregulatory and behavioral responses were similar between dosages, but different between types of phytases. Birds supplemented with fungal phytase used sensible heat dissipation mechanisms and exhibited thermal comfort behaviors. The 300 and 900 FTUs phytase doses did not influence the thermoregulatory and behavioral responses of birds, while they showed natural heat dissipation and heat stress behaviors in the afternoon. We recommend a dietary supplementation of 300 FTUs fungal phytases.     

Does a trade‐off between current reproductive success and survival affect the honesty of male signalling in species with male parental care?

Recent theory predicted that male advertisement will reliably signal investment in paternal care in species where offspring survival requires paternal care and males allocate resources between advertisement and care. However, the predicted relationship between care and advertisement depended on the marginal gains from investment in current reproductive traits. Life history theory suggests that these fitness gains are also subject to a trade‐off between current and future reproduction. Here, we investigate whether male signalling remains a reliable indicator of parental care when males allocate resources between current advertisement, paternal care and survival to future reproduction. We find that advertisement is predicted to remain a reliable signal of male care but that advertisement may cease to reliably indicate male quality because low‐quality males are predicted to invest in current reproduction, whereas higher‐quality males are able to invest in both current reproduction and survival to future reproduction.     

Does the morphological fit between flowers and pollinators affect pollen deposition? An experimental test in a buzz‐pollinated species with anther dimorphism

Some pollination systems, such as buzz‐pollination, are associated with floral morphologies that require a close physical interaction between floral sexual organs and insect visitors. In these systems, a pollinator's size relative to the flower may be an important feature determining whether the visitor touches both male and female sexual organs and thus transfers pollen between plants efficiently. To date, few studies have addressed whether in fact the “fit” between flower and pollinator influences pollen transfer, particularly among buzz‐pollinated species. Here we use Solanum rostratum, a buzz‐pollinated plant with dimorphic anthers and mirror‐image flowers, to investigate whether the morphological fit between the pollinator's body and floral morphology influences pollen deposition. We hypothesized that when the size of the pollinator matches the separation between the sexual organs in a flower, more pollen should be transferred to the stigma than when the visitor is either too small or too big relative to the flower. To test this hypothesis, we exposed flowers of S. rostratum with varying levels of separation between sexual organs, to bumblebees (Bombus terrestris) of different sizes. We recorded the number of visits received, pollen deposition, and fruit and seed production. We found higher pollen deposition when bees were the same size or bigger than the separation between anther and stigma within a flower. We found a similar, but not statistically significant pattern for fruit set. In contrast, seed set was more likely to occur when the size of the flower exceeded the size of the bee, suggesting that other postpollination processes may be important in translating pollen receipt to seed set. Our results suggest that the fit between flower and pollinator significantly influences pollen deposition in this buzz‐pollinated species. We speculate that in buzz‐pollinated species where floral morphology and pollinators interact closely, variation in the visitor's size may determine whether it acts mainly as a pollinator or as a pollen thief (i.e., removing pollen rewards but contributing little to pollen deposition and fertilization).     

Does detritus quality predict the effect of native and non‐native plants on the performance of larval amphibians?

1. The lack of consistent differences between the traits of native and non‐native plant species makes it difficult to make general predictions about the ecological impact of invasive plants; however, the increasing number of non‐native plants in many habitats makes the assessment of the impact of each individual species impracticable. General knowledge about how specific plant traits are linked to their effects on communities or ecosystems may be more useful for predicting the effect of plant invasions. Specifically, we hypothesised that higher carbon‐to‐nitrogen ratio (C:N) and percent lignin in plant detritus would reduce the rate of development and total mass at metamorphosis of tadpoles, resulting in lower metamorph production (total fresh biomass) and amphibian species richness. 2. To test these hypotheses, we raised five species of tadpoles in mesocosms containing senescent leaves of three common native and three common non‐native wetland plants that varied in C:N ratio and % lignin. 3. Leaf mass loss, total metamorph production and the number of species that metamorphosed declined as a function of increasing C:N ratio of plant leaves. Plant lignin content was not related to the production of metamorphs or the number of species that metamorphosed. The percentage of wood frog (Lithobates sylvaticus) and American toad (Anaxyrus americanus) tadpoles reaching metamorphosis declined as a function of increasing plant C:N ratio. Mean time to metamorphosis increased and mean mass at metamorphosis declined as a function of increasing plant C:N ratio. Tadpole performance and metamorph diversity and production (biomass) were similar between native and non‐native plant species with similar C:N ratio in leaves. Percent lignin was not a significant predictor of tadpole performance. 4. Our results show that the impact of a plant invasion on tadpole performance could depend on differences between the quality of the detritus produced by the invading species and that of the native species it replaces. We suggest that plant community changes that lead to dominance by more recalcitrant plant species (those with higher leaf C:N ratio) may negatively affect amphibian populations.