Testing competing hypotheses about the behaviour of floral visitors in mixed‐flower stands

2021 ◽  
Author(s):  
Melbi Alejandro Ramos‐Fabiel ◽  
Carlos Martorell
Keyword(s):  
Floral Visitors ◽  
Competing Hypotheses

The "Core" of the Dark Triad: A test of competing hypotheses

2019 ◽  
Author(s):  
Colin Vize ◽  
Donald Lynam ◽  
Katherine Collison ◽  
Josh Miller
Keyword(s):  
Dark Triad ◽  
The Core ◽  
Large Samples ◽  
Parsimonious Explanation ◽  
Shared Variance ◽  
Competing Hypotheses ◽  
Callous Affect

As research on the Dark Triad (DT; the interrelated constructs of Machiavellianism, narcissism, and psychopathy) has accumulated, a subset of this research has focused on explicating what traits may account for the overlap among the DT members. Various candidate traits have been investigated, with evidence supporting several of them including Antagonism (vs. Agreeableness), Honesty-Humility, and Callousness and Interpersonal Manipulation (the latter two as a set). The present study sought to test the leading candidates against one another in their ability to account for the shared variance among the DT members. Using a pre-registered analytical plan, we found that Agreeableness (as measured by the IPIP-NEO-120), Honesty-Humility from the HEXACO, and the SRP-III subscales of Callous Affect and Interpersonal Manipulation accounted for all or nearly all of the shared variance among the DT members. BFI-based measures of Agreeableness (BFI and BFI-2) accounted for notably less variance in most cases. The results were consistent across two large samples (Ns of 627 and 628), and across various DT measurement approaches. We argue that the most parsimonious explanation for findings on the core of the DT is that such traits all fall under the umbrella of Antagonism.

scholarly journals Selective pollination by fungus gnats potentially functions as an alternative reproductive isolation among five Arisaema species

2020 ◽  
Author(s):  
Tetsuya K Matsumoto ◽  
Muneto Hirobe ◽  
Masahiro Sueyoshi ◽  
Yuko Miyazaki
Keyword(s):  
Reproductive Isolation ◽  
Altitudinal Gradient ◽  
Flowering Phenology ◽  
Altitudinal Distribution ◽  
Interspecific Differences ◽  
Flower Visitation ◽  
Fungus Gnats ◽  
Floral Visitor ◽  
Floral Visitors ◽  
Experimental Plots

Abstract Background and Aims Interspecific difference in pollinators (pollinator isolation) is important for reproductive isolation in flowering plants. Species-specific pollination by fungus gnats has been discovered in several plant taxa, suggesting that they can contribute to reproductive isolation. Nevertheless, their contribution has not been studied in detail, partly because they are too small for field observations during flower visitation. To quantify their flower visitation, we used the genus Arisaema (Araceae) because the pitcher-like spathe of Arisaema can trap all floral visitors. Methods We evaluated floral visitor assemblage in an altitudinal gradient including five Arisaema species. We also examined interspecific differences in altitudinal distribution (geographic isolation) and flowering phenology (phenological isolation). To exclude the effect of interspecific differences in altitudinal distribution on floral visitor assemblage, we established 10 experimental plots including the five Arisaema species on high- and low-altitude areas and collected floral visitors. We also collected floral visitors in three additional sites. Finally, we estimated the strength and contribution of these three reproductive barriers using the unified formula for reproductive isolation. Key Results Each Arisaema species selectively attracted different fungus gnats in the altitudinal gradient, experimental plots, and additional sites. Altitudinal distribution and flowering phenology differed among the five Arisaema species, whereas the strength of geographic and phenological isolations were distinctly weaker than those in pollinator isolation. Nevertheless, the absolute contribution of pollinator isolation to total reproductive isolation was weaker than geographic and phenological isolations, because pollinator isolation functions after the two early-acting barriers in plant life history. Conclusions Our results suggest that selective pollination by fungus gnats potentially contributes to reproductive isolation. Since geographic and phenological isolations can be disrupted by habitat disturbance and interannual climate change, the strong and stable pollinator isolation might compensate for the weakened early-acting barriers as an alternative reproductive isolation among the five Arisaema species.

024 Quiescent Wakefulness: Characterising the Impact of Oxytocin on Sleep-Wake Behaviour in Male and Female Rats

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A11-A11
Author(s):  
Joel Raymond ◽  
Nicholas Everett ◽  
Anand Gururajan ◽  
Michael Bowen
Keyword(s):  
Rem Sleep ◽  
Sleep Onset ◽  
Conscious State ◽  
Positive Control ◽  
Female Rats ◽  
Male And Female ◽  
Routes Of Administration ◽  
Male And Female Rats ◽  
Competing Hypotheses ◽  
The Impact

Abstract Introduction Oxytocin is a versatile hypothalamic neuropeptide involved in diverse neurobehavioural processes. Since oxytocin can elicit anxiolytic and serenic effects, one could hypothesise that oxytocin should prime the brain for sleep and promote hypnogenesis. However, based on the social salience hypothesis—that oxytocin promotes prosocial behaviour and directs attention toward social stimuli—one could also posit that oxytocin should promote wakefulness. At present, little research has comprehensively characterised the effect of oxytocin on sleep-wake behaviour and no explanation to reconcile these two seemingly competing hypotheses has been proposed. Methods This study investigated the effects of oxytocin on sleep-wake outcomes using radiotelemetry-based polysomnography in adult male and female Wistar rats. Oxytocin was administered via the intraperitoneal (IP; 0.1, 0.3 and 1 mg/kg) and intranasal (IN; 0.06, 1, 3 mg/kg) routes. Caffeine (IP and IN; 10 mg/kg) was also administered as a wake-promoting positive control. Additionally, pre-treatment with the oxytocin receptor (OTR) antagonist L-368,899 (IP; 5 mg/kg) and vasopressin 1a receptor (V1aR) antagonist SR49059 (IP; 1 mg/kg) followed by oxytocin (IP; 1 mg/kg) was conducted to determine which receptor(s) mediated sleep-wake effects of oxytocin. Results In both male and female rats, IP oxytocin produced dose-dependent effects on sleep-wake behaviour. Specifically, oxytocin initially promoted quiescent wakefulness (a restful but conscious state) at the cost of reducing both active wakefulness and sleep. Throughout the 1.5-hour period post-administration, oxytocin delayed REM sleep onset and reduced the proportion of both NREM and REM sleep. Conversely, IN oxytocin did not significantly alter any sleep-wake parameters at any dose tested. Caffeine demonstrated wake-promoting effects under both the IP and IN routes of administration. The involvement of OTR and V1aR binding in oxytocin-induced effects on sleep-wake outcomes will be discussed. Conclusion These findings appear to reconcile the two competing hypotheses: in rats, IP oxytocin appears to promote a state of quiescent wakefulness—one of calm and rest, but also of conscious responsivity to environmental stimuli. IN oxytocin demonstrated little to no effect on sleep-wake behaviour, which is a crucial finding given the escalating use of IN oxytocin as a therapeutic for conditions with comorbid disordered sleep. Support (if any) None.

scholarly journals Reproductive traits and floral visitors of Aechmea distichantha plants growing in different habitats of a South American xerophytic forest

Rodriguésia ◽  
2018 ◽  
Vol 69 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Rodrigo M. Freire ◽  
Ignacio M. Barberis ◽  
José L. Vesprini
Keyword(s):  
Reproductive Traits ◽  
Climatic Conditions ◽  
Similar Proportion ◽  
South American ◽  
The Sun ◽  
Carpenter Bee ◽  
Carpenter Bees ◽  
Vegetative Traits ◽  
Floral Visitors ◽  
Almost All

Abstract Aechmea distichantha, a widely-distributed facultative epiphytic bromeliad species, is present from rainforests to xerophytic forests. At its southernmost distribution (Humid Chaco) it grows in the understory and forest edges. This animal-pollinated bromeliad shows high phenotypic plasticity on its vegetative traits, but there is no information about plasticity on its reproductive traits. Infructescences from shade plants were heavier, had longer rachis, more spikelets, higher number of fruits/spikelet and higher number of seeds/fruit than those from sun plants, but they presented similar number of open flowers. The number of visitation events was similar in both habitats, but more flowers were visited in the sun than in the shade. Flowers were visited by seven species (six insects and one hummingbird). In the sun, the carpenter bee was the most frequent visitor and visited almost all flowers, whereas in the shade different species of visitors attained similar proportion of visits and number of visited flowers. Despite visitation events were similar in both habitats, plants growing in the shade set more seeds/fruit than plants growing in the sun. The higher proportion of visits accomplished by carpenter bees compared to hummingbirds is probably a consequence of the climatic conditions in the austral location of these populations.

scholarly journals The Pericardial Body of Ciona intestinalis Contains Hemocytes and Degenerating Muscle Cells, But No Parasites

2020 ◽  
Author(s):  
Lilly Rohlfs ◽  
Katja Müller ◽  
Thomas Stach
Keyword(s):  
Immune System ◽  
Model Organism ◽  
Gene Sequencing ◽  
Ciona Intestinalis ◽  
Sister Group ◽  
Myocardial Cells ◽  
Histological Techniques ◽  
Transmission Electron ◽  
Ascidian Species ◽  
Competing Hypotheses

Abstract Purpose A ventral heart positioned posterior to the branchial basket and equipped with a pericardium is homologous in tunicates and their sister group, the craniates, yet the tunicate model organism Ciona intestinalis features a pericardial body, a structure peculiar to few ascidian species. Here, we set out to distinguish between two competing hypotheses regarding the function of the pericardial body found in the literature: (H1) The pericardial body performs a role in the removal of dysfunctional myocardial cells, and (H2) it is a specialized niche of the immune system involved in defense against parasites. Methods We used histological techniques, transmission electron microscopy, and PCR-based gene sequencing to investigate whether individual ascidians parasitized with apicomplexan protists show signs of infections within the pericardial body. Results In individuals of C. intestinalis from the German North Sea infested with apicomplexan protists, the pericardial body contains numerous myocardial cells in various stages of degeneration while no remnants of parasitic cells could be identified. Conclusion Thus, we conclude that H2—the pericardial body is a specialized niche of the immune system involved in defense against parasites—can be refuted. Rather, our observations support H1, the hypothesis that the pericardial body performs a role in the removal of dysfunctional myocardial cells.

Labor Hoarding and SRIRL Pardox: Some Evidences from United Kingdom and United States

1997 ◽  
Vol 1 (1) ◽  
pp. 175-189
Author(s):  
Yongkyun Chung
Keyword(s):  
United States ◽  
United Kingdom ◽  
Business Cycle ◽  
Direct Measurement ◽  
Recent Literature ◽  
Competing Hypotheses ◽  
Procyclical Productivity ◽  
Labor Hoarding

The purpose of this study is to investigate the significance of the labor hoarding phenomenon in explaining the SRIRL paradox, or procyclical productivity. Accordingly previous work in these areas is particularly important. First, the direct measurement of labor hoarding shows how prominent the labor hoarding phenomenon is in various industries. Second, evidences of SRIRL at business cycle frequencies are mixed. Third, recent literature on labor hoarding tests indicates that labor hoarding is an indispensible ingredient to explain SRIRL or procyclical productivity among competing hypotheses.

Systematic status of Campydora Cobb, 1920 (Nematoda: Campydorina)

Nematology ◽  
2003 ◽  
Vol 5 (5) ◽  
pp. 699-711 ◽  
Author(s):  
Peter Mullin ◽  
Timothy Harris ◽  
Thomas Powers
Keyword(s):  
Maximum Likelihood ◽  
Ribosomal Dna ◽  
Dna Sequences ◽  
Maximum Parsimony ◽  
Phylogenetic Analyses ◽  
Small Subunit ◽  
Systematic Position ◽  
Nominal Species ◽  
Competing Hypotheses ◽  
Small Subunit Ribosomal Dna

AbstractThe systematic position of Campydora Cobb, 1920, which possesses many unique morphological features, especially in pharyngeal structure and stomatal armature, has long been a matter of uncertainty with the 'position of the Campydorinae' (containing only Campydora) being questionable. A review of the morphology of C. demonstrans, the only nominal species of Campydora concluded that the species warranted placement as the sole member of a monotypic suborder, Campydorina, in the order Dorylaimida. Others placed Campydorina in the order Enoplida. We conducted phylogenetic analyses, using 18s small subunit ribosomal DNA sequences generated from a number of taxa in the subclasses Enoplia and Dorylaimia, to evaluate these competing hypotheses. Although precise taxonomic placement of the genus Campydora and the identity of its closest living relatives is in need of further investigation, our analyses, under maximum parsimony, distance, and maximum likelihood criteria, unambiguously indicate that Campydora shares a common, more recent, ancestry with genera such as Alaimus, Pontonema, Tripyla and Ironus (Enoplida), rather than with any members of Dorylaimida, Mononchida or Triplonchida.

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