Do pollinators influence the assembly of flower colours within plant communities?

The co-occurrence of plant species within a community is influenced by local deterministic or neutral processes as well as historical regional processes. Floral trait distributions of co-flowering species that share pollinators may reflect the impact of pollinator preference and constancy on their assembly within local communities. While pollinator sharing may lead to increased visitation rates for species with similar flowers, the receipt of foreign pollen via interspecific pollinator movements can decrease seed set. We investigated the pattern of community flower colour assembly as perceived by native honeybee pollinators within 24 local assemblages of co-flowering Oxalis species within the Greater Cape Floristic Region, South Africa. To explore the influence of pollinators on trait assembly, we assessed the impact of colour similarity on pollinator choices and the cost of heterospecific pollen receipt. We show that flower colour is significantly clustered within Oxalis communities and that this is not due to historical constraint, as flower colour is evolutionarily labile within Oxalis and communities are randomly structured with respect to phylogeny. Pollinator observations reveal that the likelihood of pollinators switching between co-flowering species is low and increases with flower colour similarity. Interspecific hand pollination significantly reduced seed set in the four Oxalis species we investigated, and all were dependant on pollinators for reproduction. Together these results imply that flower colour similarity carries a potential fitness cost. However, pollinators were highly flower constant, and remained so despite the extreme similarity of flower colour as perceived by honeybees. This suggests that other floral traits facilitate discrimination between similarly coloured species, thereby likely resulting in a low incidence of interspecific pollen transfer (IPT). If colour similarity promotes pollinator attraction at the community level, the observed clustering of flower colour within communities might result from indirect facilitative interactions.     

How Do People Become W.E.I.R.D.? Migration Reveals the Cultural Transmission Mechanisms Underlying Variation in Psychological Processes

Cultural psychologists have shown that people from Western, Educated, Industrialised, Rich, Democratic (WEIRD) countries often exhibit different psychological processing to people from less-WEIRD countries. The former exhibit more individualistic and less collectivistic social orientation, and more analytic and less holistic cognition, than non-Westerners. Yet the mechanisms responsible for maintaining this cultural variation are unclear. Immigration is an ideal ‘natural experiment’ for uncovering such mechanisms. We used a battery of psychological measures previously shown to vary cross-culturally to compare the social orientation and cognitive style of 286 residents of East London from three cultural backgrounds: (i) 1^st-generation British Bangladeshi immigrants; (ii) 2^nd-generation British Bangladeshis raised in the UK to Bangladeshi-raised parents; and (iii) non-migrants whose parents were born and raised in the UK. Model comparison revealed that individualism and dispositional attribution, typical of Western societies, are driven primarily by horizontal cultural transmission (e.g. via mass media), with parents and other family members having little or no effect, while collectivism, social closeness and situational attribution were driven by a mix of vertical/oblique cultural transmission (e.g. via family contact) and horizontal cultural transmission. These individual-level transmission dynamics can explain hitherto puzzling population-level phenomena, such as the partial acculturation of 2^nd-generation immigrants on measures such as collectivism (due to the mix of vertical and horizontal cultural transmission), or the observation in several countries of increasing individualism (which is transmitted horizontally and therefore rapidly) despite little corresponding change in collectivism (which is transmitted partly vertically and therefore more slowly). Further consideration of cultural transmission mechanisms, in conjunction with the study of migrant communities and model comparison statistics, can shed light on the persistence of, and changes in, culturally-variable psychological processes.     

Do pollinators determine hybridization patterns in sympatricSatyrium (Orchidaceae) species?

The breakdown of species integrity was studied in three sympatricSatyrium (Orchidaceae) species at a site in the Western Cape province of South Africa. Hybrids with intermediate morphology were identified using multivariate analysis.Satyrium erectum ×S. bicorne andS. erectum ×S. coriifolium hybrids were common, while only oneS. bicorne ×S. coriifolium hybrid was found (a new record). Reciprocal artificial crossing experiments confirmed that genetic compatibility exists between all three species. However, the species have different pollinators: moths inS. bicorne, bees inS. erectum and sunbirds inS. coriifolium. Pollinators, rather than genetic factors, therefore, appear to be responsible for reproductive isolation between these species. Breakdown in pollinator specificity results in interspecific pollen transfer and the formation of hybrids. Overlap in floral signals, including nocturnal scent in bothS. erectum andS. bicorne, and bright coloration in bothS. erectum andS. coriifolium, facilitates the formation of hybrids between these species pairs. The brown, scented flowers ofS. bicorne, on the other hand, share no obvious floral signals with the bright orange, unscented flowers ofS. coriifolium, accounting for the rarity of hybrids between this species pair. Differences in floral morphology also result in mechanical isolation between these two species. Since the three species are sympatric in a very small part of their geographic ranges, it is unlikely that avoidance of hybridization has been an important selective factor in the evolution of specialized pollination systems.     

New bis-thioglycosyl-1,1′-disulfides from Nasturtium officinale R. Br. and their anti-neuroinflammatory effect

As a part of our continuing search for bioactive constituents from Brassicaceae family, three new bis-thioglycosides (1–3) were isolated from the 80% MeOH extract of Nasturtium officinale, together with 13 known compounds (4–16). The chemical structures of three new bis-thioglycosides (1–3) were elucidated using NMR techniques (¹H and ¹³C NMR, ¹H–¹H COSY, HSQC, and HMBC), HRESIMS, and a chemical method. All the compounds were evaluated for their inhibitory effects on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Among the isolates, compound 5 exhibited a strong inhibitory effect on NO production, and compounds 4 and 15 showed moderate inhibitory activities, suggesting the neuroprotective and anti-neuroinflammatory effects of bis-thioglycosides from N. officinale.     

Do mesocosms influence photosynthesis and soil respiration?

Mesocosms, enclosed outdoor experimental systems, are commonly used in terrestrial ecology. They are frequently used to study the effects of elevated CO₂ and temperature on terrestrial ecosystem processes. Despite their advantages and frequent use it is important to verify, through explicit measures, that mesocosms reliably model the larger system. In this study, fully-coupled, soil–litter–plant mesocosms were constructed in Corvallis using native soil and litter, and planted with Douglas-fir (Pseudotsuga menziesii Mirb. Franco) seedlings. Needle photosynthesis and soil respiration were measured repeatedly over a 21-month period in mesocosms and compared to measurements made at two field sites (Toad Creek and Falls Creek) planted at the same density as the mesocosms. Under the temperature and soil moisture conditions, photosynthetic and soil respiration rates in the mesocosms were not significantly different than the rates at Toad Creek, where the soil and litter in the mesocosms were collected. In contrast, the soil at Falls Creek was different than the soil in the mesocosms and at Toad Creek and photosynthetic and soil respiration rates at Falls Creek were significantly different than at the other two sites. The lack of significant differences between rates measured in the mesocosms in Corvallis and at the Toad Creek field site indicate that the mesocosms did not cause significant artifacts in the data and that the results for these rates in the mesocosms can be extrapolated to field settings with comparable edaphic conditions.     

How big are educational and racial fertility differentials in the U.S.?

Using pooled data from the 1980, 1985, 1990 and 1995 CPS and 1988 and 1995 NSFG surveys, we show that shifts in fertility timing have occurred disproportionately for the more educated and for whites (compared to the less educated and to African Americans). Such timing shifts imply that the underlying period quantum of fertility is considerably higher for college-educated women and for whites than suggested by the standard total fertility rate. Applying the Bongaarts-Feeney model (1998), we decompose observed racial and educational differences in age-order-specific fertility rates and TFR into tempo and quantum components. We find that a modest part of educational differences and a substantial part of racial difference in period fertility can be attributed to differential changes in tempo. Analysis by race and education shows a clear interaction: higher fertility among African Americans is confined to the less educated.     

Über strahleninduzierte Letalfaktoren im S-Chromosom vonMattbiola incana R. Br.

Ohne ZusammenfassungMit 3 Abbildungen     

Do farming conditions influence brominated flame retardant levels in pig and poultry products?

Brominated flame retardants (BFR) are primarily used as flame retardant additives in insulating materials. These lipophilic compounds can bioaccumulate in animal tissues, leading to human exposure via food ingestion. Although their concentration in food is not yet regulated, several of these products are recognised as persistent organic pollutants; they are thought to act as endocrine disruptors. The present study aimed to characterise the occurrence of two families of BFRs (hexabromocyclododecane (HBCDD) and polybrominated diphenyl ethers (PBDE)) in hen eggs and broiler or pig meat in relation to their rearing environments. Epidemiological studies were carried out on 60 hen egg farms (34 without an open-air range, 26 free-range), 57 broiler farms (27 without an open-air range, 30 free-range) and 42 pig farms without an open-air range in France from 2013 to 2015. For each farm, composite samples from either 12 eggs, five broiler pectoral muscles or three pig tenderloins were obtained. Eight PBDE congeners and three HBCDD stereoisomers were quantified in product fat using gas chromatography–high-resolution mass spectrometry, or high-performance liquid chromatography–tandem mass spectrometry, respectively. The frequencies of PBDE detection were 28% for eggs (median concentration 0.278 ng/g fat), 72% for broiler muscle (0.392 ng/g fat) and 49% for pig muscle (0.403 ng/g fat). At least one HBCDD stereoisomer was detected in 17% of eggs (0.526 ng/g fat), 46% of broiler muscle (0.799 ng/g fat) and 36% of pig muscle (0.616 ng/g fat). Results were similar in concentration to those obtained in French surveillance surveys from 2012 to 2016. Nevertheless, the contamination of free-range eggs and broilers was found to be more frequent than that of conventional ones, suggesting that access to an open-air range could be an additional source of exposure to BFRs for animals. However, the concentration of BFRs in all products remained generally very low. No direct relationship could be established between the occurrence of BFRs in eggs and meat and the characteristics of farm buildings (age, building materials). The potential presence of BFRs in insulating materials is not likely to constitute a significant source of animal exposure as long as the animals do not have direct access to these materials.     

The influence of pollinators and seed predation on seed production in dwarf grassland Protea “sugarbushes” (Proteaceae)

Flowers of many plant species are visited by both birds and insects, making it necessary to establish their relative contributions to seed set. In Protea, available evidence points to an overwhelming preponderance of bird-pollination systems in the genus, but the scented flowers of several dwarf grassland “sugarbush” species suggest that some Protea species may be adapted for insect pollination. In this study, we used both selective exclusion of vertebrates and complete exclusion of all visitors to investigate whether the insects that visit the scented flowerheads of three Protea species (Protea dracomontana, Protea simplex and Protea welwitschii) in KwaZulu-Natal, South Africa contribute to seed production. We also performed supplemental hand pollinations to test for pollen limitation. Seed set was generally higher in inflorescences subjected to vertebrate exclusion than in those from which all visitors were excluded, suggesting that fertile cross-pollen was deposited by insects, but these differences were slight because of high levels of self-fertilization in the study species. Pollen deposition and pollen tube growth were similar for vertebrate-excluded and open-pollinated inflorescences. Supplemental hand-pollination treatments revealed that seed set in P. simplex and P. welwitschii was not pollen-limited. Overall seed set was low, typical of the family Proteaceae, and infructescences were highly predated by lepidopteran larvae. We conclude that insects are likely to contribute to seed set of the study species, but further studies using molecular markers are required to establish the actual level of insect-mediated outcrossing.     

Eine Zwillingsblüte beiGymnadenia conopea (L.) R. Br.

Ohne Zusammenfassung     

Do climate and soil influence phenotypic variability in leaf litter,microbial decomposition and shredder consumption?

We tested the hypothesis that water stress and soil nutrient availability drive leaf-litter quality for decomposers and detritivores by relating chemical and physical leaf-litter properties and decomposability of Alnus glutinosa and Quercus robur, sampled together with edaphic parameters, across wide European climatic gradients. By regressing principal components analysis of leaf traits [N, P, condensed tannins, lignin, specific leaf area (SLA)] against environmental and soil parameters, we found that: (1) In Q. robur the condensed tannin and lignin contents increased and SLA decreased with precipitation, annual range of temperature, and soil N content, whereas leaf P increased with soil P and temperature; (2) In A. glutinosa leaves N, P, and SLA decreased and condensed tannins increased with temperature, annual range of temperature, and decreasing soil P. On the other hand, leaf P and condensed tannins increased and SLA decreased with minimum annual precipitation and towards sites with low temperature. We selected contrasting leaves in terms of quality to test decomposition and invertebrate consumption. There were intraspecific differences in microbial decomposition rates (field, Q. robur) and consumption by shredders (laboratory, A. glutinosa). We conclude that decomposition rates across ecosystems could be partially governed by climate and soil properties, affecting litter quality and therefore decomposers and detritivores. Under scenarios of global warming and increased nutrients, these results suggest we can expect species-specific changes in leaf-litter properties most likely resulting in slow decomposition with increased variance in temperatures and accelerated decomposition with P increase.     

Do changes in seaweed biodiversity influence associated invertebrate epifauna?

Most investigations of biogenic habitat provision consider the promotion of local biodiversity by single species, yet habitat-forming species are often themselves components of diverse assemblages. Increased prevalence of anthropogenic changes to assemblages of habitat-forming species prompts questions about the importance of facilitator biodiversity to associated organisms. We used observational and short-term (30 days) manipulative studies of an intertidal seaweed system to test for the implications of changes in four components of biodiversity (seaweed species richness, functional group richness, species composition, and functional group composition) on associated small mobile invertebrate epifauna. We found that invertebrate epifauna richness and abundance were not influenced by changes in seaweed biodiversity. Invertebrate assemblage structure was in most cases not influenced by changes in seaweed biodiversity; only when algal assemblages were composed of monocultures of species with ‘foliose’ morphologies did we observe a difference in invertebrate assemblage structure. Correlations between algal functional composition and invertebrate assemblage structure were observed, but there was no correlation between algal species composition and invertebrate assemblage structure. These results suggest that changes in seaweed biodiversity are likely to have implications for invertebrate epifauna only under specific scenarios of algal change.     

Do diet and taxonomy influence insect gut bacterial communities?

Many insects contain diverse gut microbial communities. While several studies have focused on a single or small group of species, comparative studies of phylogenetically diverse hosts can illuminate general patterns of host–microbiota associations. In this study, we tested the hypotheses that (i) host diet and (ii) host taxonomy structure intestinal bacterial community composition among insects. We used published 16S rRNA gene sequence data for 58 insect species in addition to four beetle species sampled from the Sevilleta National Wildlife Refuge to test these hypotheses. Overall, gut bacterial species richness in these insects was low. Decaying wood xylophagous insects harboured the richest bacterial gut flora (102.8 species level operational taxonomic units (OTUs)/sample ± 71.7, 11.8 ± 5.9 phylogenetic diversity (PD)/sample), while bees and wasps harboured the least rich bacterial communities (11.0 species level OTUs/sample ± 5.4, 2.6 ± 0.8 PD/sample). We found evidence to support our hypotheses that host diet and taxonomy structure insect gut bacterial communities (P < 0.001 for both). However, while host taxonomy was important in hymenopteran and termite gut community structure, diet was an important community structuring factor particularly for insect hosts that ingest lignocellulose‐derived substances. Our analysis provides a baseline comparison of insect gut bacterial communities from which to test further hypotheses concerning proximate and ultimate causes of these associations.     

Gedanken über ein system der Oxycocco-Sphagnetea Br.-Bl. & R. Tx. 1943

Zusammenfassung Viele Gründe sprechen für eine Trennung der Bult-Assoziationen Sphagnetum papillosi und Sphagnetum medii, die nach der Dominanz der Sphagnen ohne Schwierigkeiten möglich ist.Für die Sphagneta medii und die Sphagneta papillosi werden einige Gebietsassoziationen und Rassen beschrieben.Die alte Gliederung der Oxycocco-Sphagnetea von Schwickerath wird als richtig angesehen und erneut zur Annahme vorgeschlagen.

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Summary Many reasons speak in favour of a separation of the hummock-associations Sphagnetum papillosi and Sphagnetum medii, which is easily practicable according to the dominance of the Sphagna.Some territorial associations and races are described for the Sphagneta medii and the Sphagneta papillosi.The old classification of the Oxycocco-Sphagnetea by Schwickerath is regarded as correct and proposed to acceptance.

     

Coleoptile length,gibberellin sensitivity and concentrations in five non-allelic dwarf mutants of pearl millet — Pennisetum glaucum (L.) R. Br.

The concentrations of endogenous gibberellins (GAs) were determined by combined gas chromatography-mass spectrometry in shoots of five non-allelic dwarfs of pearl millet Pennisetum glaucum (L.) R. Br. One mutant (d3), with an extreme dwarf phenotype, was found to be deficient in all GAs measured; the others (d1, d2, d4 and the quantitatively inherited dwarf) had similar levels of GAs to the tall genotype. Only the GA-deficient dwarf recovered the tall phenotype in response to applying GA₃ up to the adult stage, while the others showed slight to moderate responses at the seedling stage, depending on the season, and no response at later stages. The d1, d3 and d4 dwarfs had short coleoptiles. A wide range of coleoptile lengths with a normal distribution pattern was observed in the tall, d2 and the quantitatively inherited dwarf, suggesting that there is polygenic control of this trait.     

Karyological and serological studies in Rana lessonae,R. ridibunda and in their hybrid R. ‘esculenta’ (Amphibia,Anura)

The karyotypes of the three water frog forms: Rana lessonae, R. ridibunda and R. esculenta were analysed from bone marrow cell preparations of animals captured in several localities of the GDR. In the three forms chromosome morphology was similar (5 large and 8 small pairs), although differences in the relative length of most elements were found; R. esculenta chromosomes were always intermediate.One of the small pairs (Chr. 12) was found to be metacentric in R. lessonae and submetacentric in R. ridibunda. Most R. esculenta individuals examined had one meta-and one submetacentric 12th element, indicating the hybrid nature of this form. However 16.6% esculenta proved to be homozygous for either the metacentric or the submetacentric chromosome 12, while 13% lessonae individuals and 7.7% ridibunda were heterozygous for this element.By starch gel electrophoresis an analysis was undertaken of serum proteins from water frogs coming from regions in which the forms occur together (sympatric populations) and from zones in which only one of them lives (allopatric populations).In Rana lessonae, where only one allele had been previously described, two different alleles were found in animals coming from the GDR.If genetic polymorphism is excluded, between 6.1% and 9.1% individuals from sympatric lessonae and ridibunda populations showed introgression of an albumin allele. No gene introgression was found in allopatric lessonae populations from the Leningrad region or in ridibunda from Alma Ata and southern Bulgaria.     

Do group size and laying order influence maternal deposition of testosterone in smooth-billed ani eggs?

The avian egg contains maternal hormones that affect behavior, growth, morphology, and offspring survival. Evidence to date suggests that patterns of yolk androgen deposition could provide females with a means to manipulate sibling competition and, thereby, increase their fitness. We examined yolk testosterone (T) concentrations in eggs of the smooth-billed ani (Crotophaga ani) to understand patterns of androgen deposition in eggs of this plural-breeding joint-nesting cooperatively breeding species. We tested the hatching asynchrony adjustment hypothesis, which states that increases in yolk androgen levels over the laying sequence function to mitigate the disadvantage of being a later-hatched chick in species without adaptive brood reduction. We also investigated the effect of group size on yolk T deposition to test the hypothesis that females in multi-female groups could give a competitive edge to their own chicks by depositing higher T levels in their eggs. Predictions of the hatching asynchrony adjustment hypothesis were supported in both single- and multi-female groups as yolk testosterone levels increased from early- to late-laid eggs. This suggests that ani females can influence nestling competition and chick survival by within-clutch differential T allocation. Unexpectedly, we did not observe an effect of group size on yolk T deposition. Yolk testosterone concentrations may not be a mere reflection of a female's hormonal status as female plasma circulating levels of T did not vary in the same direction as yolk T levels. Results of this study therefore support the idea that females may adaptively manipulate chick behavior through hormonal deposition in eggs.     

Do peer relations in adolescence influence health in adulthood? Peer problems in the school setting and the metabolic syndrome in middle-age

While the importance of social relations for health has been demonstrated in childhood, adolescence and adulthood, few studies have examined the prospective importance of peer relations for adult health. The aim of this study was to examine whether peer problems in the school setting in adolescence relates to the metabolic syndrome in middle-age. Participants came from the Northern Swedish Cohort, a 27-year cohort study of school leavers (effective n = 881, 82% of the original cohort). A score of peer problems was operationalized through form teachers' assessment of each student's isolation and popularity among school peers at age 16 years, and the metabolic syndrome was measured by clinical measures at age 43 according to established criteria. Additional information on health, health behaviors, achievement and social circumstances were collected from teacher interviews, school records, clinical measurements and self-administered questionnaires. Logistic regression was used as the main statistical method. Results showed a dose-response relationship between peer problems in adolescence and metabolic syndrome in middle-age, corresponding to 36% higher odds for the metabolic syndrome at age 43 for each SD higher peer problems score at age 16. The association remained significant after adjustment for health, health behaviors, school adjustment or family circumstances in adolescence, and for psychological distress, health behaviors or social circumstances in adulthood. In analyses stratified by sex, the results were significant only in women after adjustment for covariates. Peer problems were significantly related to all individual components of the metabolic syndrome. These results suggest that unsuccessful adaption to the school peer group can have enduring consequences for metabolic health.     

Breeding system of the critically endangered Lakela’s Mint and influence of plant height on pollinators and seed output

Understanding reproductive systems of rare plants is critical for conservation efforts. Lakela's Mint, Dicerandra immaculata Lakela var. immaculata, is an endangered plant endemic to an approximately 4.8-km long area in Florida, USA. We used an experimental garden and three populations of Lakela's Mint to determine: (1) what is the breeding system (autonomous, asexual, self-fertile, cross-fertile) and are insects necessary for reproduction; (2) which native and nonnative insect species visit flowers and is the frequency of visits to a plant influenced by its height; (3) does the number of flowers visited within a plant by individual insects differ among native and nonnative insect species and due to plant height; and (4) is seed output influenced by plant height? Our results indicate that the breeding system of Lakela's Mint was facultative outcrossing. Insect-pollinated flowers produced more seeds than flowers that reproduced autonomously or asexually. The honey bee Apis mellifera L., a nonnative species, was the most frequent visitor to plants and visited more flowers within plants than native pollinators, but its behavior was not influenced by plant height. Native pollinators such as Bombus impatiens Cresson were attracted more frequently to shorter plants, but visited fewer flowers than on taller plants. Despite having fewer total and pollinated flowers, shorter plants had a higher output of intact seeds than taller plants, which could be due to differences in efficiency between native and nonnative pollinators or other factors. Our results add insight into factors influencing seed output and interactions between pollinators and rare plants.