scholarly journals Sexual dimorphism in the turtle Kinosternon scorpioides (Testudines: Kinosternidae) from Marajó Island, Brazilian Amazon

2021 ◽  
Vol 69 (2) ◽  
pp. 601-614
Author(s):  
Joilson Silva Da Silva ◽  
Brenda Stefany Dos Santos Braga ◽  
Juliane Da Silva Costa ◽  
Leandro Schlemmer Brasil ◽  
Verônica Regina Lobato De Oliveira-Bahia ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Difference ◽  
Low Cost ◽  
Anatomical Landmarks ◽  
Sample Collection ◽  
Biometric Analysis ◽  
Morphometry Analysis ◽  
Mud Turtle ◽  
Marajó Island ◽  
Environmental Events

Introduction: Morphometrics analysis is an efficient and low-cost technique used in studies of sexual dimorphism in turtles. Kinosternon scorpioides scorpioides, scorpion mud turtle, has a wide phenotypic variation, depending on the area of its occurrence. Objective: The objective of this work was to identify the anatomical sexual difference of K. s. scorpioides, adults and hatchlings, through morphometric analysis; and relate the weights of adult animals to environmental factors (temperature and rainfall) in Marajó Island, Brazil. Methods: The sample collection was carried out from March to September 2018, covering both the rainy season (January to July) and the dry season (August to December). For the biometric analysis, 95 adults and 21 hatchlings were used, in which the length and width of the carapace and plastron, height of the shell, and weight were measured (adults only). For the geometric morphometry analysis, 21 adults and 13 hatchlings were used, in which 27 coordinates of anatomical landmarks were inserted in each image of the carapace and 11 in the plastron. Hatchlings were sexed by histology which was enabled by the identification of the ovaries and testicles. Results: The results showed the existence of dimorphism in adults. The plastron and height were higher in females, which had a more rounded carapace than males. This characteristic may be related to the species' sexual strategy, where males impose copulation. Histologically, it was possible to identify the ovaries and testicles in the hatchlings, but there was no anatomical sexual difference, despite the tendency to differentiate in the analysis of carapace PCA. Conclusions: Sexual dimorphism in K. s. scorpioides may play an important role on its reproductive behavior, which is synchronized with environmental events. This fact suggests that the reproductive strategies of this species would be severely affected by changes in the ecosystem.

scholarly journals Technical Note: Evaluation of a low-cost evaporation protection method for portable water samplers

2020 ◽  
Author(s):  
Jana von Freyberg ◽  
Julia L. A. Knapp ◽  
Andrea Rücker ◽  
Bjørn Studer ◽  
James W. Kirchner
Keyword(s):  
Water Samples ◽  
Low Cost ◽  
Isotopic Fractionation ◽  
Field Tests ◽  
Isotopic Signature ◽  
Technical Note ◽  
Stable Water Isotopes ◽  
Sample Collection ◽  
Protection Method ◽  
Cost Efficient

Abstract. Automated field sampling of streamwater or precipitation for subsequent analysis of stable water isotopes (2H and 18O) is often conducted with off-the-shelf automated samplers. However, water samples stored in the field for days and weeks in open bottles inside autosamplers undergo isotopic fractionation and vapor mixing, thus altering their isotopic signature. We therefore designed an evaporation protection method which modifies autosampler bottles using a syringe housing and silicone tube, and tested whether this method reduces evaporative fractionation and vapor mixing in water samples stored for up to 24 days in ISCO autosamplers (Teledyne ISCO., Lincoln, US). Laboratory and field tests under different temperature and humidity conditions showed that water samples in bottles with evaporation protection were far less altered by evaporative fractionation and vapor mixing than samples in conventional open bottles. Our design is a cost-efficient approach to upgrade the 1-litre sample bottles of ISCO 6712 Full-size Portable Samplers, allowing secure water sample collection in warm and dry environments. Our design can be readily adapted (e.g., by using a different syringe size) to fit the bottles used by many other field autosamplers.

scholarly journals Habitat, Sexual and Allometric Influences on Morphological Traits of Intertidal Crabs

2020 ◽  
Author(s):  
P. Vermeiren ◽  
C. Lennard ◽  
C. Trave
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Morphological Traits ◽  
Low Cost ◽  
Habitat Preferences ◽  
Mangrove Crab ◽  
Habitat Factors ◽  
Specific Factors ◽  
Claw Shape

Abstract Intertidal crabs display distinct morphological traits that allow differential interactions with biotic and abiotic features of the intertidal landscape, but are also influenced by allometry and sexual selection. This study aimed to explore the influence of sexual, allometric and habitat factors on morphological variation in the intertidal mangrove crab assemblage. A standardized photographic protocol was developed using readily available, low-cost technology to capture the morphology of carapaces and claws as sets of Cartesian landmarks. Digitization errors were 1 to 2 orders of magnitude smaller than the variation among individuals. In Tubuca seismella and Tubuca signata (superfamily Ocypodoidea), species that have traditionally been studied for sexual dimorphism, standardized major claw sizes were 2.8 and 3.7, respectively, times larger for males than females. Sexual dimorphism in claw size was also observed for Metopograpsus frontalis and Parasesarma longicristatum (superfamily Grapsoidea), with the largest claw in males being 15% and 33%, respectively, larger than in females. In contrast to size, claw shape did not relate to sex, except for T. seismella. Carapace shape, although variable among individuals and displaying asymmetry, was unrelated to sex. Claw and carapace shapes displayed high correlations, with values around 0.78. Carapace shapes grouped into taxonomic families and linked to habitat preferences, while claw shapes varied along a taxonomic gradient. These results complement studies on crab morphology that focus on specific factors or species, and stress the importance of multiple, interacting factors including sexual, allometric and habitat influences as drivers of morphological trait variability.

scholarly journals Using Noninvasive Genetic Sampling to Survey Rare Butterfly Populations

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 311
Author(s):  
Caroline Storer ◽  
Jaret Daniels ◽  
Lei Xiao ◽  
Kristin Rossetti
Keyword(s):  
Captive Breeding ◽  
Low Cost ◽  
Genetic Material ◽  
Breeding Population ◽  
Sample Collection ◽  
Genetic Sampling ◽  
Miami Blue Butterfly ◽  
Analysis Laboratory ◽  
Conservation Concern ◽  
Future Evaluation

Advances in nondestructive genetic sampling techniques continue to offer new opportunities for studying organisms, particularly those of conservation concern where more traditional invasive sampling methods are often not available. As part of a proof-of-concept, we investigated the effectiveness of using the chorion from residual butterfly egg debris as a source of viable genetic material for analysis. Laboratory material from a captive breeding population of the federally endangered Miami blue butterfly (Cyclargus thomasi bethunebakeri) was used to test efficacy and refine the methodology. The resulting best practices were subsequently evaluated using field-collected material from extant north Florida populations of the at-risk frosted elfin butterfly (Callophyrs irus). Our results demonstrated that it is possible to extract DNA of sufficiently high quantity and quality for successful gene sequencing. We additionally describe a simple, low-cost, and reliable method of collecting and storing egg debris samples that can be consistently adopted for field or laboratory work as well as deployed with projects that have a larger geographic scope and/or involve citizen scientists. Potential limitations related to field sample collection are discussed as well as needs for future evaluation.

The State and Future of Blood-Based Biomarkers in the Health and Retirement Study

2011 ◽  
Vol 14 (3) ◽  
Author(s):  
Thomas McDade
Keyword(s):  
Survey Design ◽  
Low Cost ◽  
Reproductive Function ◽  
Health And Retirement Study ◽  
Sample Collection ◽  
Advantages And Disadvantages ◽  
Methods Development ◽  
Wide Range ◽  
Primary Focus ◽  
Retirement Study

The Health and Retirement Study (HRS) is an important national resource for policy makers and investigators across a wide range of disciplines, and it is critical that the study collects the best information possible on the health status of its participants within the constraints of the survey design, and without compromising the integrity of the sample. Potential directions for the collection and analysis of biomarker data in future waves of HRS are discussed, with a primary focus on blood-based biomarkers. Advantages and disadvantages of various methods for collecting blood in the home are considered, with particular attention given to the strengths and weaknesses of dried blood spot (DBS) sampling. DBS sampling has been widely applied in recent biosocial surveys due to the low cost and burden associated with sample collection, but these benefits need to be weighed against challenges associated with quantification in the laboratory. Attention is also given to additional biomarkers that may be of relevance to HRS, and that would expand the survey’s current focus on obesity and metabolic syndrome. Measures of inflammation, pathogen exposure, reproductive function, stress, and epigenetic modifications are suggested as potentially productive future directions for the study. In addition, the analysis concludes with the following recommendations for HRS: Continue to collect DBS samples, but consider alternatives; implement enhanced procedures for quality control; calibrate DBS results against plasma values, and invest in methods development.

scholarly journals Technical note: Evaluation of a low-cost evaporation protection method for portable water samplers

2020 ◽  
Vol 24 (12) ◽  
pp. 5821-5834
Author(s):  
Jana von Freyberg ◽  
Julia L. A. Knapp ◽  
Andrea Rücker ◽  
Bjørn Studer ◽  
James W. Kirchner
Keyword(s):  
Water Samples ◽  
Low Cost ◽  
Field Tests ◽  
Technical Note ◽  
Water Isotopes ◽  
Stable Water Isotopes ◽  
Sample Collection ◽  
Isotopic Signatures ◽  
Protection Method ◽  
Cost Efficient

Abstract. Automated field sampling of streamwater or precipitation for subsequent analysis of stable water isotopes (2H and 18O) is often conducted with off-the-shelf automated samplers. However, when water samples are stored in the field for days and weeks in open bottles inside autosamplers, their isotopic signatures can be altered by evaporative fractionation and vapor mixing. We therefore designed an evaporation protection method which modifies autosampler bottles using a syringe housing and silicone tube, and we tested whether this method reduces evaporative fractionation and vapor mixing in water samples stored for up to 24 d in 6712 full-size portable samplers (Teledyne ISCO, Lincoln, USA). Laboratory and field tests under different temperature and humidity conditions showed that water samples in bottles with evaporation protection were far less altered by evaporative fractionation and vapor mixing than samples in conventional open bottles. Our design is a cost-efficient approach to upgrade the 1 L sample bottles of the ISCO autosamplers, allowing secure water sample collection in warm and dry environments. Our design can be readily adapted (e.g., by using a different syringe size) to fit the bottles used by many other field autosamplers.

scholarly journals A microfluidic platform for highly parallel bite by bite profiling of mosquito-borne pathogen transmission

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shailabh Kumar ◽  
Felix J. H. Hol ◽  
Sujit Pujhari ◽  
Clayton Ellington ◽  
Haripriya Vaidehi Narayanan ◽  
...  
Keyword(s):  
Low Cost ◽  
Blood Feeding ◽  
Pathogen Transmission ◽  
Membrane Thickness ◽  
Sample Collection ◽  
Microfluidic Platform ◽  
Virus Particles ◽  
Virus Rna ◽  
On Chip ◽  
Mayaro Virus

AbstractMosquito bites transmit a number of pathogens via salivary droplets deposited during blood-feeding, resulting in potentially fatal diseases. Little is known about the genomic content of these nanodroplets, including the transmission dynamics of live pathogens. Here we introduce Vectorchip, a low-cost, scalable microfluidic platform enabling high-throughput molecular interrogation of individual mosquito bites. We introduce an ultra-thin PDMS membrane which acts as a biting interface to arrays of micro-wells. Freely-behaving mosquitoes deposit saliva droplets by biting into these micro-wells. By modulating membrane thickness, we observe species-dependent differences in mosquito biting capacity, utilizable for selective sample collection. We demonstrate RT-PCR and focus-forming assays on-chip to detect mosquito DNA, Zika virus RNA, as well as quantify infectious Mayaro virus particles transmitted from single mosquito bites. The Vectorchip presents a promising approach for single-bite-resolution laboratory and field characterization of vector-pathogen communities, and could serve as a powerful early warning sentinel for mosquito-borne diseases.

Skull morphological variation in a British stranded population of false killer whale (Pseudorca crassidens): a three-dimensional geometric morphometric approach

2022 ◽  
pp. 119-132
Author(s):  
Deborah Vicari ◽  
Richard C. Sabin ◽  
Richard P. Brown ◽  
Olivier Lambert ◽  
Giovanni Bianucci ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Killer Whale ◽  
Three Dimensional ◽  
Anatomical Landmarks ◽  
Geometric Morphometric ◽  
False Killer Whale ◽  
Sexual Shape Dimorphism ◽  
Males And Females ◽  
Pseudorca Crassidens

The false killer whale (Pseudorca crassidens (Owen, 1846)) is a globally distributed delphinid that shows geographical differentiation in its skull morphology. We explored cranial morphological variation in a sample of 85 skulls belonging to a mixed sex population stranded in the Moray Firth, Scotland, in 1927. A three-dimensional digitizer (Microscribe 2GX) was used to record 37 anatomical landmarks on the cranium and 25 on the mandible to investigate size and shape variation and to explore sexual dimorphism using geometric morphometric. Males showed greater overall skull size than females, whereas no sexual dimorphism could be identified in cranial and mandibular shape. Allometric skull changes occurred in parallel for both males and females, supporting the lack of sexual shape dimorphism for this particular sample. Also, fluctuating asymmetry did not differ between crania of males and females. This study confirms the absence of sexual shape dimorphism and the presence of a sexual size dimorphism in this false killer whale population.

Dominance style, differences between the sexes and individuals

2004 ◽  
Vol 5 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Charlotte K. Hemelrijk ◽  
Lorenz Gygax
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Sexual Difference ◽  
Artificial Agents ◽  
Dominance Style ◽  
Egalitarian Society ◽  
Males And Females ◽  
Species Specific ◽  
Initial Capacity

In recent studies of primates, the question has been raised whether competitive regimes (egalitarian versus despotic) are species-specific or should rather be considered as sex-specific. To study this problem we use an individual-oriented model called DomWorld in which artificial agents are equipped merely to group and compete. In former studies of this model, dominance style appeared to be strongly influenced by the intensity of aggression: by increasing only this intensity of aggression, a great number of the characteristics of an egalitarian society switched to those of a despotic one. Here, we investigate, using DomWorld, a competitive regime of artificial males and females that differ exclusively in their fighting capacity; males having a higher intensity of aggression and a higher initial capacity of winning, such as may be due to a male-biased sexual dimorphism. Unexpectedly it appears that, in the model, even if the intensity of aggression of males is greater than that of females, their hierarchy is still significantly weaker and thus their society less differentiated and more egalitarian than that of females. The explanation is that, due to the higher initial dominance of males (compare larger body size), single events of victory and defeat lead to less differentiation than among females. The greater the sexual difference in initial dominance between the sexes is the more egalitarian the males behave among themselves compared to the behaviour of the females among themselves. These effects are already visible during the initial phases of the hierarchical development. These results resemble findings among primates; in real primates their degree of sexual dimorphism may influence the competitive regime of each sex.

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