scholarly journals Size dimorphism and sexual segregation in pheasants: tests of three competing hypotheses

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5674 ◽  
Author(s):  
Mark A. Whiteside ◽  
Jayden O. van Horik ◽  
Ellis J.G. Langley ◽  
Christine E. Beardsworth ◽  
Joah R. Madden
Keyword(s):  
Predation Risk ◽  
Activity Budget ◽  
Sexual Segregation ◽  
Sexually Dimorphic ◽  
Fine Scale ◽  
Size Dimorphism ◽  
Selection Hypothesis ◽  
Wide Range ◽  
In The Wild ◽  
Species Specific

Fine scale sexual segregation outside of the mating season is common in sexually dimorphic and polygamous species, particularly in ungulates. A number of hypotheses predict sexual segregation but these are often contradictory with no agreement as to a common cause, perhaps because they are species specific. We explicitly tested three of these hypotheses which are commonly linked by a dependence on sexual dimorphism for animals which exhibit fine-scale sexual segregation; the Predation Risk Hypothesis, the Forage Selection Hypothesis, and the Activity Budget Hypothesis, in a single system the pheasant, Phasianus colchicus; a large, sedentary bird that is predominantly terrestrial and therefore analogous to ungulates rather than many avian species which sexually segregate. Over four years we reared 2,400 individually tagged pheasants from one day old and after a period of 8–10 weeks we released them into the wild. We then followed the birds for 7 months, during the period that they sexually segregate, determined their fate and collected behavioural and morphological measures pertinent to the hypotheses. Pheasants are sexually dimorphic during the entire period that they sexually segregate in the wild; males are larger than females in both body size and gut measurements. However, this did not influence predation risk and predation rates (as predicted by the Predation Risk Hypothesis), diet choice (as predicted by the Forage Selection Hypothesis), or the amount of time spent foraging, resting or walking (as predicted by the Activity Budget Hypothesis). We conclude that adult sexual size dimorphism is not responsible for sexual segregation in the pheasant in the wild. Instead, we consider that segregation may be mediated by other, perhaps social, factors. We highlight the importance of studies on a wide range of taxa to help further the knowledge of sexual segregation.

Sexual segregation in bison: a test of multiple hypotheses

Behaviour ◽  
2005 ◽  
Vol 142 (7) ◽  
pp. 897-927 ◽  
Author(s):  
Eric W. Schaad ◽  
David S. Wiseman ◽  
Royce R. Huber ◽  
Michael S. Mooring ◽  
Dominic D. Reisig ◽  
...  
Keyword(s):  
Body Size ◽  
Predation Risk ◽  
Sexual Segregation ◽  
Bison Bison ◽  
Sexually Dimorphic ◽  
Activity Budgets ◽  
Single Sex ◽  
Multiple Hypotheses ◽  
Mixed Groups ◽  
Large Groups

AbstractSexual segregation, in which males and females form separate groups for most of the year, is common in sexually dimorphic ungulates. We tested multiple hypotheses to explain sexual segregation in bison (Bison bison) at National Bison Range, Montana and Fort Niobrara National Wildlife Refuge, Nebraska during June-August of 2002-2003. Fieldwork involved use of GPS to record space use by segregated groups, vegetation transects to measure forage availability, fecal analyses to document diet composition and quality, and behavioural observations to characterize activity budgets. During sexual segregation, males in bull groups used areas with greater per capita abundance of forage, higher proportion of weeds, and less nutritious grasses (as indicated by lower % fecal nitrogen) compared with females in cow or mixed groups. However, there was no difference between the sexes in activity budgets, predation risk factors, or distance to water. Single-sex bull groups were no more synchronized in activity than mixed groups. These results support the 'sexual dimorphism-body size hypothesis', which proposes that males segregate from females because their larger body size requires more abundant forage, while longer ruminal retention permits efficient use of lower-quality forage. The gastrocentric model, based on the digestive physiology and foraging requirements of dimorphic ungulates, supplies the most likely proximate mechanism for bison sexual segregation. Our results would also partly support the 'reproductive strategy-predation risk hypothesis' if females form large groups to reduce predation risk. The predictions of the 'activity budget hypothesis' were not supported for bison.

Sexual segregation in European cyprinids: consequence of response to predation risk influenced by sexual size dimorphism

Hydrobiologia ◽  
2020 ◽  
Vol 847 (6) ◽  
pp. 1439-1451 ◽  
Author(s):  
Jakub Žák ◽  
Marie Prchalová ◽  
Marek Šmejkal ◽  
Petr Blabolil ◽  
Mojmír Vašek ◽  
...  
Keyword(s):  
Predation Risk ◽  
Sexual Size Dimorphism ◽  
Sexual Segregation ◽  
Size Dimorphism

Backpacking with the Saints

2015 ◽  
Author(s):  
Belden C. Lane
Keyword(s):  
American Southwest ◽  
Spiritual Practice ◽  
Spiritual Journey ◽  
Human Response ◽  
John Muir ◽  
Hildegard Of Bingen ◽  
Wide Range ◽  
Thich Nhat Hanh ◽  
In The Wild ◽  
John Of The Cross

Carrying only basic camping equipment and a collection of the world's great spiritual writings, Belden C. Lane embarks on solitary spiritual treks through the Ozarks and across the American Southwest. For companions, he has only such teachers as Rumi, John of the Cross, Hildegard of Bingen, Dag Hammarskjöld, and Thomas Merton, and as he walks, he engages their writings with the natural wonders he encounters--Bell Mountain Wilderness with Søren Kierkegaard, Moonshine Hollow with Thich Nhat Hanh--demonstrating how being alone in the wild opens a rare view onto one's interior landscape, and how the saints' writings reveal the divine in nature. The discipline of backpacking, Lane shows, is a metaphor for a spiritual journey. Just as the wilderness offered revelations to the early Desert Christians, backpacking hones crucial spiritual skills: paying attention, traveling light, practicing silence, and exercising wonder. Lane engages the practice not only with a wide range of spiritual writings--Celtic, Catholic, Protestant, Buddhist, Hindu, and Sufi Muslim--but with the fascination of other lovers of the backcountry, from John Muir and Ed Abbey to Bill Plotkin and Cheryl Strayed. In this intimate and down-to-earth narrative, backpacking is shown to be a spiritual practice that allows the discovery of God amidst the beauty and unexpected terrors of nature. Adoration, Lane suggests, is the most appropriate human response to what we cannot explain, but have nonetheless learned to love. An enchanting narrative for Christians of all denominations, Backpacking with the Saints is an inspiring exploration of how solitude, simplicity, and mindfulness are illuminated and encouraged by the discipline of backcountry wandering, and of how the wilderness itself becomes a way of knowing-an ecology of the soul.

Species-specific duplex PCR for the detection of Pratylenchus penetrans

Nematology ◽  
2009 ◽  
Vol 11 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Lieven Waeyenberge ◽  
Nicole Viaene ◽  
Maurice Moens
Keyword(s):  
Internal Control ◽  
Dna Sequences ◽  
Rrna Gene ◽  
Duplex Pcr ◽  
Specific Primers ◽  
5.8S Rrna Gene ◽  
5.8S Rrna ◽  
Wide Range ◽  
Pcr Products ◽  
Species Specific

Abstract ITS1, the 5.8S rRNA gene and ITS2 of the rDNA region were sequenced from 20 different Pratylenchus species. Additionally, the same region was sequenced from seven populations of P. penetrans. After purifying, cloning and sequencing the PCR products, all sequences were aligned in order to find unique sites suitable for the design of species-specific primers for P. penetrans. Since ITS regions showed variability between and even within populations of P. penetrans, only three small DNA sequences were suitable for the construction of three potentially useful species-specific primers. New species-specific primers were paired with existing universal ITS primers and tested in all possible primer combinations. The best performing primer set, supplemented with a universal 28S rDNA primer set that served as an internal control, was tested in duplex PCR. The ideal annealing temperature, Mg2+ concentration and primer ratios were then determined for the most promising primer set. The optimised duplex PCR was subsequently tested on a wide range of different Pratylenchus spp. and 25 P. penetrans populations originating from all over the world. To test the sensitivity, the duplex PCR was conducted on DNA extracted from a single P. penetrans nematode mixed with varying amounts of nematodes belonging to another Pratylenchus species. Results showed that a reliable and sensitive P. penetrans species-specific duplex PCR was constructed.

Plasticity in sexual size dimorphism and Rensch’s rule in Mediterranean blennies (Blenniidae)

2008 ◽  
Vol 86 (10) ◽  
pp. 1173-1178 ◽  
Author(s):  
W. Lengkeek ◽  
K. Didderen ◽  
I. M. Côté ◽  
E. M. van der Zee ◽  
R. C. Snoek ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Sexual Size Dimorphism ◽  
Fine Scale ◽  
Evolutionary Patterns ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Close Proximity ◽  
Species Comparisons ◽  
Aidablennius Sphynx

Comparative analyses of sexual size dimorphism (SSD) across species have led to the discovery of Rensch’s rule. This rule states that SSD increases with body size when males are the largest sex, but decreases with increasing size when females are larger. Within-species comparisons of SSD in fish are rare, yet these may be a valuable tool to investigate evolutionary patterns on a fine scale. This study compares SSD among closely related populations of three species of Mediterranean blennies (Blenniidae): Microlipophrys canevae (Vinciguerra, 1880), Parablennius incognitus (Bath 1968), and Aidablennius sphynx (Valenciennes, 1836). SSD varied more among populations than among species and Rensch’s rule was confirmed within two species. It is not likely that the variation among populations in SSD mirrors genetic variation, as many of the populations were in close proximity of one another, with a high potential for genetic exchange. This study complements larger scale analyses of other taxa and demonstrates the fine scale on which evolutionary processes responsible for Rensch’s rule may be operating.

scholarly journals Evaluation of an enrichment programme for a colony of long-tailed macaques (Macaca fascicularis) in a rescue centre

Primates ◽  
2021 ◽  
Author(s):  
Valeria Albanese ◽  
Michela Kuan ◽  
Pier Attilio Accorsi ◽  
Roberta Berardi ◽  
Giovanna Marliani
Keyword(s):  
Animal Models ◽  
Biomedical Research ◽  
Macaca Fascicularis ◽  
Activity Budget ◽  
Control Session ◽  
Abnormal Behaviour ◽  
Species Specific ◽  
Low Rate

AbstractLong-tailed macaques are highly social primates that are commonly used in biomedical research as animal models. The aim of this study was to evaluate the effects of different kinds of enrichment on the behaviour and faecal cortisol metabolite (FCM) level in a colony of ex-laboratory long-tailed macaques during a programme of rehabilitation. The research was carried out in three periods, divided into two sessions each. Every period was composed of one control session (SC) and one session characterised by one type of enrichment: feeding enrichment (FE), manipulative enrichment (ME), and the last session during which manipulative and feeding enrichment were provided every day but in a mixed way (MIX). The results showed that manipulative and mixed enrichments caused positive changes to the activity budget of the colony, with a decrease in abnormal behaviour rates and an increase in play compared with control sessions. The rate of affiliative behaviours and low rate of aggression were probably because the group was composed mostly of females and it was stable, with a well-defined hierarchy. The research underlines the importance of a well-studied enrichment programme for the welfare of captive animals, which should exploit species-specific motivations.

scholarly journals Deciphering the evolution of microbial interactions: in silico studies of two-member microbial communities

2022 ◽  
Author(s):  
Gayathri Sambamoorthy ◽  
Karthik Raman
Keyword(s):  
Microbial Communities ◽  
In Silico ◽  
Microbial Interactions ◽  
Interaction Patterns ◽  
Wild Type ◽  
Community Function ◽  
Evolutionary Forces ◽  
In Silico Studies ◽  
Wide Range ◽  
In The Wild

Microbes thrive in communities, embedded in a complex web of interactions. These interactions, particularly metabolic interactions, play a crucial role in maintaining the community structure and function. As the organisms thrive and evolve, a variety of evolutionary processes alter the interactions among the organisms in the community, although the community function remains intact. In this work, we simulate the evolution of two-member microbial communities in silico to study how evolutionary forces can shape the interactions between organisms. We employ genomescale metabolic models of organisms from the human gut, which exhibit a range of interaction patterns, from mutualism to parasitism. We observe that the evolution of microbial interactions varies depending upon the starting interaction and also on the metabolic capabilities of the organisms in the community. We find that evolutionary constraints play a significant role in shaping the dependencies of organisms in the community. Evolution of microbial communities yields fitness benefits in only a small fraction of the communities, and is also dependent on the interaction type of the wild-type communities. The metabolites cross-fed in the wild-type communities appear in only less than 50% of the evolved communities. A wide range of new metabolites are cross-fed as the communities evolve. Further, the dynamics of microbial interactions are not specific to the interaction of the wild-type community but vary depending on the organisms present in the community. Our approach of evolving microbial communities in silico provides an exciting glimpse of the dynamics of microbial interactions and offers several avenues for future investigations.

scholarly journals Mycorrhizal Communities and Isotope Signatures in Two Partially Mycoheterotrophic Orchids

2021 ◽  
Vol 12 ◽  
Author(s):  
Hans Jacquemyn ◽  
Rein Brys ◽  
Michael Waud ◽  
Alexandra Evans ◽  
Tomáš Figura ◽  
...  
Keyword(s):  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Wide Range ◽  
Terrestrial Orchids ◽  
Significant Enrichment ◽  
Mycoheterotrophic Plants ◽  
C And N ◽  
Species Specific ◽  
Epipactis Helleborine ◽  
Isotope Analyses

Partial mycoheterotrophy, the ability of plants to obtain carbon from fungi throughout their life cycle in combination with photosynthesis, appears to be more common within the Plant Kingdom than previously anticipated. Recent studies using stable isotope analyses have indicated that isotope signatures in partially mycoheterotrophic plants vary widely among species, but the relative contributions of family- or species-specific characteristics and the identity of the fungal symbionts to the observed differences remain unclear. Here, we investigated in detail mycorrhizal communities and isotopic signatures in four co-occurring terrestrial orchids (Platanthera chlorantha, Epipactis helleborine, E. neglecta and the mycoheterotrophic Neottia nidus-avis). All investigated species were mycorrhizal generalists (i.e., associated with a large number of fungi simultaneously), but mycorrhizal communities differed significantly between species. Mycorrhizal communities associating with the two Epipactis species consisted of a wide range of fungi belonging to different families, whereas P. chlorantha and N. nidus-avis associated mainly with Ceratobasidiaceae and Sebacinaceae species, respectively. Isotopic signatures differed significantly between both Epipactis species, with E. helleborine showing near autotrophic behavior and E. neglecta showing significant enrichment in both carbon and nitrogen. No significant differences in photosynthesis and stomatal conductance were observed between the two partially mycoheterotrophic orchids, despite significant differences in isotopic signatures. Our results demonstrate that partially mycoheterotrophic orchids of the genus Epipactis formed mycorrhizas with a wide diversity of fungi from different fungal families, but variation in mycorrhizal community composition was not related to isotope signatures and thus transfer of C and N to the plant. We conclude that the observed differences in isotope signatures between E. helleborine and E. neglecta cannot solely be explained by differences in mycorrhizal communities, but most likely reflect a combination of inherent physiological differences and differences in mycorrhizal communities.

scholarly journals Thermal fractionation of soil organic matter produces fine-scale distributions of SOM age

2021 ◽  
Author(s):  
Shane Stoner ◽  
Carlos Sierra ◽  
Marion Schrumpf ◽  
Sebastian Dötterl ◽  
Susan Trumbore
Keyword(s):  
Thermal Stability ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Chemical Oxidation ◽  
Fine Scale ◽  
Mineral Association ◽  
Density Fractions ◽  
Chemical Complexity ◽  
Wide Range ◽  
Carbon Release

<p>Soil organic matter (SOM) is a complex collection of organic molecules of varying origin, structure, chemical activity, and mineral association. A wide array of laboratory methods exists to separate SOM based on qualitative, biological, chemical, and physical characteristics. However, all present conceptual and logistical limitations, including the requirement of a substantial amount soil material.</p><p>An newly applied alternative method of fractionation relies on a conceptual analogue between biochemical stability in soil and thermal stability, e.g. more persistent SOM will require higher temperatures (greater energy inputs) to decompose than less persistent SOM. This accounts for both chemical complexity and mineral association as main factors in determining SOM persistence.</p><p>In this method, carbon is released by heating SOM to 900°C at a constant rate. The peaks of carbon release are grouped into activation energy pools, CO<sub>2 </sub>is collected, and analyzed for <sup>13</sup>C and <sup>14</sup>C. We seek to describe in finer detail the distribution of soil radiocarbon by adding another fractionation step following a different paradigm of SOM stability, and explore mineralogical effects on SOM quality and stability using thermal analysis, radiocarbon, and gas chromatography.</p><p>Here, we analyzed bulk soil and soil fractions derived from density separation and chemical oxidation, as well as mineral horizons dominated by diverse mineralogies. Density fractions contained a wide range of radiocarbon activities and that young SOM is stabilized across multiple fractions, likely due to organomineral complexation. Initial results showed that soil minerals with limited stabilization potential released C at lower temperatures than those with diverse stabilization mechanisms. High-temperature sub-fractions contained the oldest carbon across fractions and minerals, thus supporting the assumption that thermal stability can be used as a limited analogue for stability in soil. We present a fine-scale distribution of radiocarbon in SOM and discuss the potential of this method for comparison with other fractionation techniques.</p>

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