Disseminating Intention: How a term has spread within cross-species comparative science.

The current study takes a holistic view of cross-species comparative research and investigates the dissemination of the term intention as representative of the so-called "cognitive revolution." All references from 641 articles, published from 1948 to 2017, are used to analyze a citation network. The analysis visualizes and identifies prominent articles in the scientific debate and locates them structurally on a map. Each article is categorized in terms of the school of thought, its position within the discourse (e.g., opposing, supporting), the order of intentionality (e.g., 1st or 2nd order), and the species under consideration. By using a mixed-methods approach, which combines qualitative and quantitative methods, we identified 2 divergent schools of thought (psychological/philosophical and biological/behavioristic). Both schools introduced intention mostly independently from each other and show little overlap in citation habits. Both notions of intention have influenced comparative science until today. However, although the term finds limited application in various schools, only in connection with more cognitive approaches has it enjoyed a successful career, as indicated by the increasing number of articles in which it is used. Most controversy does not surround the concept of intention itself but its order. Furthermore, taking account of which species are investigated could reveal a pronounced primate bias in past discourse. Articles on nonprimate species using the term intention in the cognitive sense are markedly outnumbered by those on primates. The study reminds comparative psychologists of the importance to integrate a historical perspective into current debates, to avoid "speciesism" and talking past each other. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Genetic and Genomic Analyses Reveal Boundaries between Species Closely Related to Cryptococcus Pathogens.

Speciation is a central mechanism of biological diversification. While speciation is well studied in plants and animals, in comparison, relatively little is known about speciation in fungi. One fungal model is the Cryptococcus genus, which is best known for the pathogenic Cryptococcus neoformans/Cryptococcus gattii species complex that causes >200,000 new human infections annually. Elucidation of how these species evolved into important human-pathogenic species remains challenging and can be advanced by studying the most closely related nonpathogenic species, Cryptococcus amylolentus and Tsuchiyaea wingfieldii However, these species have only four known isolates, and available data were insufficient to determine species boundaries within this group. By analyzing full-length chromosome assemblies, we reappraised the phylogenetic relationships of the four available strains, confirmed the genetic separation of C. amylolentus and T. wingfieldii (now Cryptococcus wingfieldii), and revealed an additional cryptic species, for which the name Cryptococcus floricola is proposed. The genomes of the three species are ∼6% divergent and exhibit significant chromosomal rearrangements, including inversions and a reciprocal translocation that involved intercentromeric ectopic recombination, which together likely impose significant barriers to genetic exchange. Using genetic crosses, we show that while C. wingfieldii cannot interbreed with any of the other strains, C. floricola can still undergo sexual reproduction with C. amylolentus However, most of the resulting spores were inviable or sterile or showed reduced recombination during meiosis, indicating that intrinsic postzygotic barriers had been established. Our study and genomic data will foster additional studies addressing fungal speciation and transitions between nonpathogenic and pathogenic Cryptococcus lineages.IMPORTANCE The evolutionary drivers of speciation are critical to our understanding of how new pathogens arise from nonpathogenic lineages and adapt to new environments. Here we focus on the Cryptococcus amylolentus species complex, a nonpathogenic fungal lineage closely related to the human-pathogenic Cryptococcus neoformans/Cryptococcus gattii complex. Using genetic and genomic analyses, we reexamined the species boundaries of four available isolates within the C. amylolentus complex and revealed three genetically isolated species. Their genomes are ∼6% divergent and exhibit chromosome rearrangements, including translocations and small-scale inversions. Although two of the species (C. amylolentus and newly described C. floricola) were still able to interbreed, the resulting hybrid progeny were usually inviable or sterile, indicating that barriers to reproduction had already been established. These results advance our understanding of speciation in fungi and highlight the power of genomics in assisting our ability to correctly identify and discriminate fungal species.

Flowers anticipate revisits of pollinators by learning from previously experienced visitation intervals.

Plants - and their pollinating counterparts - display complex and sophisticated mechanisms to achieve successful pollination. It probably was only a matter of time for proof of plant intelligence in the context of floral ecology to surface, i.e. the memorization of previous events and a corresponding adjustment of flower behavior. In a recent study we presented a large experimental dataset on the evolution of stamen movement patterns observed in Loasaceae and the apparent role of plant behavior in the diversification of this plant group. The findings at species level suggest that individual plants may be able to adjust the timing of their pollen presentation to the actual pollination scenario they experience. Here we provide first evidence for a pre-emptive stamen presentation in Nasa poissoniana (Loasaceae), based on previously experienced pollinator visitation intervals. Using the unique ability of fast and precise stamen movements in response to a previous stimulus of the nectar scales, the plants should be able to reduce pollen loss and increase outbreeding success via optimizing the timing of male function. We discuss this behavior and its implications in the light of the recent literature and propose questions for future investigations.

A case of behavioural diversification in male floral function - the evolution of thigmonastic pollen presentation.

Obvious movements of plant organs have fascinated scientists for a long time. They have been studied extensively, but few behavioural studies to date have dealt with them, and hardly anything is known about their evolution. Here, we present a large experimental dataset on the stamen movement patterns found in the Loasaceae subfam. Loasoideae (Cornales). An evolutionary transition from autonomous-only to a combination of autonomous and thigmonastic stamen movement with increased complexity was experimentally demonstrated. We compare the stamen movement patterns with extensive pollinator observations and discuss it in the context of male mating behavior. Thigmonastic pollen presentation via stamen movements appears to be a crucial component of floral adaptation to pollinator behaviour, evolving in concert with complex adjustments of flower signal, reward and morphology. We hypothesize that rapid adjustments of pollen presentation timing may play a significant role in the diversification of this plant group, representing a striking example for the evolutionary significance of plant behaviour.

Flooding Duration Affects the Structure of Terrestrial and Aquatic Microbial Eukaryotic Communities.

The increasing number and duration of inundations is reported to be a consequence of climate change and may severely compromise non-adapted macroorganisms. The effect of flooding events on terrestrial and aquatic microbial communities is, however, less well understood. They may respond to the changed abiotic properties of their native habitat, and the native community may change due to the introduction of alien species. We designed an experiment to investigate the effect of five different flooding durations on the terrestrial and aquatic communities of eukaryotic microorganism, using the AquaFlow mesocosms. With amplicon sequencing of the small subunit (SSU) and internal transcribed spacer (ITS) rRNA gene regions, we analyzed community compositions directly before and after flooding. Subsequently, they were monitored for another 28 days, to determine the sustainability of community changes. Our results revealed a temporary increase in similarity between terrestrial and aquatic communities according to OTU composition (operational taxonomic unit, serves as a proxy for species). Increased similarity was mainly caused by the transmission of OTUs from water to soil. A minority of these were able to persist in soil until the end of the experiment. By contrast, the vast majority of soil OTUs was not transmitted to water. Flooding duration affected the community structure (abundance) more than composition (occurrence). Terrestrial communities responded immediately to flooding and the flooding duration influenced the community changes. Independent from flooding duration, all terrestrial communities recovered largely after flooding, indicating a remarkable resilience to the applied disturbances. Aquatic communities responded immediately to the applied inundations too. At the end of the experiment, they grouped according to the applied flooding duration and the amount of ammonium and chloride that leached from the soil. This indicates a sustained long-term response of the aquatic communities to flooding events.

Impact of three different fungicides on fungal epi- and endophytic communities of common bean (Phaseolus vulgaris) and broad bean (Vicia faba).

In this study, the impacts of three different fungicides to fungal phyllosphere communities on broad bean (Vicia faba, Fabaceae) and common bean (Phaseolus vulgaris, Fabaceae) were analyzed. The fungicides included copper, sulfur, and azoxystrobin. The plants were sowed, grown, and treated under conditions occurring in conventional and organic farming. A culture-based approach was used to identify changes in the phyllosphere fungal community after the treatment. Different effects on species richness and growth index of the epiphytic and endophytic communities for common bean and broad bean could be shown. Treatments with sulfur showed the weakest effect, followed by those based on copper and the systemic azoxystrobin, which showed the strongest effect especially on endophytic communities. The epiphytic fungal community took five weeks to recover after treatment with azoxystrobin. However, the effect of azoxystrobin on the endophytic community lasted more than five weeks. Finally, the data suggest that the surface structure of the host leaves have a huge impact on the mode of action that the fungicides exert.

Specialist nectar-yeasts decline with urbanization in Berlin.

Nectar yeasts are common inhabitants of insect-pollinated flowers but factors determining their distribution are not well understood. We studied the influence of host identity, environmental factors related to pollution/urbanization, and the distance to a target beehive on local distribution of nectar yeasts within Robinia pseudoacacia L. and Tilia tomentosa Moench in Berlin, Germany. Nectar samples of six individuals per species were collected at seven sites in a 2 km radius from each target beehive and plated on YM-Agar to visualise the different morphotypes, which were then identified by sequencing a section of the 26S rDNA gene. Multivariate linear models were used to analyze the effects of all investigated factors on yeast occurrence per tree. Yeast distribution was mainly driven by host identity. The influence of the environmental factors (NO2, height of construction, soil sealing) strongly depended on the radius around the tree, similar to the distance of the sampled beehive. Incidence of specialist nectar-borne yeast species decreased with increasing pollution/urbanization index. Given that specialist yeast species gave way to generalist yeasts that have a reduced dependency on pollinators for between-flower dispersal, our results indicate that increased urbanization may restrict the movement of nectar-specialized yeasts, via limitations of pollinator foraging behavior.

Nectar sugars and bird visitation define a floral niche for basidiomycetous yeast on the Canary Islands.

BACKGROUND: Studies on the diversity of yeasts in floral nectar were first carried out in the late 19th century. A narrow group of fermenting, osmophilous ascomycetes were regarded as exclusive specialists able to populate this unique and species poor environment. More recently, it became apparent that microorganisms might play an important role in the process of plant pollination. Despite the importance of these nectar dwelling yeasts, knowledge of the factors that drive their diversity and species composition is scarce. RESULTS: In this study, we linked the frequencies of yeast species in floral nectars from various host plants on the Canary Islands to nectar traits and flower visitors. We estimated the structuring impact of pollination syndromes (nectar volume, sugar concentration and sugar composition) on yeast diversity.The observed total yeast diversity was consistent with former studies, however, the present survey yielded additional basidiomycetous yeasts in unexpectedly high numbers. Our results show these basidiomycetes are significantly associated with ornithophilous flowers. Specialized ascomycetes inhabit sucrose-dominant nectars, but are surprisingly rare in nectar dominated by monosaccharides. CONCLUSIONS: There are two conclusions from this study: (i) a shift of floral visitors towards ornithophily alters the likelihood of yeast inoculation in flowers, and (ii) low concentrated hexose-dominant nectar promotes colonization of flowers by basidiomycetes. In the studied floral system, basidiomycete yeasts are acknowledged as regular members of nectar. This challenges the current understanding that nectar is an ecological niche solely occupied by ascomycetous yeasts.