Read by QxMD icon Read

Zoology: Analysis of Complex Systems, ZACS

Karine D Colpo, Laura S López-Greco
The physiological costs of reproduction can be measured as the energy allocated to reproductive activities. In fiddler crabs, females allocate energy to vitellogenesis and brooding, whereas males perform expensive courtship behaviors. We evaluated in a large-scale study the reproduction cost of females and males of Leptuca uruguayensis in a temperate estuary, where their reproductive efforts are synchronized in a short reproductive season. The reproductive investments (vitellogenesis, spermatophore production, and male reproductive behaviors) were measured and related to the dynamics of storage and expenditure of energy reserves (glycogen, total lipids, and total protein) in the hepatopancreas, ovary, and muscle of the enlarged cheliped, throughout one annual cycle...
January 11, 2018: Zoology: Analysis of Complex Systems, ZACS
Elvira Brunelli
Mounting evidence suggests that amphibians are globally and currently the most threatened group of vertebrates and different causes might be responsible for this phenomenon. Acidification of water bodies is a global environmental issue that has been proposed as a possible cause for amphibian populations decline. Indeed, it has been widely demonstrated that low pH may exert harmful effects on amphibians, either directly or by increasing the adverse effects of other stressors. Surprisingly only few studies documented the response of amphibian integument to acidic pH conditions and no data are available on the effects of a non-lethal level of pH onto the amphibian larval epidermis...
January 9, 2018: Zoology: Analysis of Complex Systems, ZACS
V H Paiva, J A Ramos, C Nava, V Neves, J Bried, M Magalhães
At-sea distribution and trophic ecology of small seabird species (i.e.<100 g) is far less known when compared to their larger relatives. We studied the habitat use (spatial ecology) and isotopic niches (trophic ecology) of the endangered Monteiro's storm-petrel Hydrobates monteiroi during the incubation and chick-rearing periods of 2013. There was a sexual foraging segregation of Monteiro's storm-petrels during the breeding period (tracking data) but also during the non-breeding stage (stable isotope analysis)...
December 30, 2017: Zoology: Analysis of Complex Systems, ZACS
Kinga Skieresz-Szewczyk, Hanna Jackowiak, Marlena Ratajczak
The lingual nail as the cornified layer of the orthokeratinized epithelium in birds is responsible for the collection of solid food by pecking. The aim of the present study is to determine the manner of orthokeratinized epithelium development and assess the degree of readiness of the epithelium to fulfill its mechanical function at hatching. Three developmental phases are distinguished, i.e. embryonic, transformation and pre-hatching stage. In the embryonic stage lasting until day 13 of incubation the epithelium is composed of several layers of undifferentiated cells...
December 28, 2017: Zoology: Analysis of Complex Systems, ZACS
Miriam M Morales, S Rocío Moyano, Agustina M Ortiz, Marcos D Ercoli, Luis I Aguado, Sergio A Cardozo, Norberto P Giannini
Leopardus wiedii (margay) is the only arboreal Neotropical felid able to climb head-first down trees, due to its ability to rotate its tarsal joint 180°. A closely related, similar-sized species, L. geoffroyi (Geoffroy's cat) exhibits more typical terrestrial habits and lacks the arboreal capabilities of L. wiedii. There is osteological evidence that supports a mechanical specialization of L. wiedii's tarsal joint for inversion, but there have been no studies on the myology of this specialization. Based on comparative gross-anatomy dissections of zeugo- and autopodial muscles related to the ankle joint of one margay specimen and two Geoffroýs cats, we identified myological specializations of L...
December 26, 2017: Zoology: Analysis of Complex Systems, ZACS
Raf Claes, Pieter G G Muyshondt, Joris J J Dirckx, Peter Aerts
High sound pressure levels (>120dB) cause damage or death of the hair cells of the inner ear, hence causing hearing loss. Vocalization differences are present between hens and roosters. Crowing in roosters is reported to produce sound pressure levels of 100dB measured at a distance of 1m. In this study we measured the sound pressure levels that exist at the entrance of the outer ear canal. We hypothesize that roosters may benefit from a passive protective mechanism while hens do not require such a mechanism...
December 24, 2017: Zoology: Analysis of Complex Systems, ZACS
Loïc Kéver, Eric Parmentier, Sofie Derycke, Erik Verheyen, Jos Snoeks, Maarten Van Steenberge, Pascal Poncin
Since prezygotic rather than postzygotic barriers are believed to maintain the diversity of closely related sympatric cichlids, differences in phenotypic traits and reproductive behaviours are likely involved in maintaining species boundaries. Here, we focused on the reproductive behaviour of three Ophthalmotilapia species with distributions that only overlap on a small stretch of the shore line of Lake Tanganyika. Repeated introgression of mitochondrial DNA between these species was previously reported, which suggested they can hybridise...
December 24, 2017: Zoology: Analysis of Complex Systems, ZACS
Marco Sannolo, Frederico M Barroso, Miguel A Carretero
Sister species living in sympatry offer the opportunity to study the degree of divergence in their ecological, physiological and life-history traits. It has been hypothesized that closely related species with overlapping distribution should differ in their niche to reduce competition for resources. Furthermore, the investigation of sympatric species may shed light on how they may coexist without outcompeting each other. In the present study, we assess the degree of physiological divergence in two sympatric lacertid lizards, Podarcis bocagei and Podarcis guadarramae lusitanicus...
December 24, 2017: Zoology: Analysis of Complex Systems, ZACS
Markus Krings, Laura Rosskamp, Hermann Wagner
Owls are known for their nocturnal hunting capability. Many owl species are able to localize prey in complete darkness just by hearing. Sound localization of strictly nocturnal owls is improved by asymmetrically arranged outer ears. According to Norberg (1977), who worked with adult owls, asymmetrical ears evolved at least four times independently among owls. What is unknown so far is how the ear asymmetry develops in the embryo. Here we examine the embryonic development of ear asymmetry in the American barn owl (Tyto furcata pratincola) in the frame of the 42 stages suggested by Köppl et al...
December 2, 2017: Zoology: Analysis of Complex Systems, ZACS
Jana Goyens, Peter Aerts
The cyclic patterns of terrestrial animal locomotion are frequently perturbed in natural environments. The terrain can be complex or inclined, the substrate can move unexpectedly and animals can misjudge situations. Loosing stability due to perturbations increases the probability of capture by predators and decreases the chance of successful prey capture and winning intraspecific battles. When controlled corrective actions are necessary to negotiate perturbations, animals rely on their exteroceptive and proprioceptive senses to monitor the environment and their own body movements...
November 29, 2017: Zoology: Analysis of Complex Systems, ZACS
Itzel Sifuentes-Romero, Boris M Tezak, Sarah L Milton, Jeanette Wyneken
Experimental and field studies of different turtle species suggest that moisture influences embryonic development and sex ratios, wetter substrates tend to produce more males, and drier substrates produce more females. In this study, we used Trachemys scripta elegans to test the effect of moisture on embryonic development and sex ratios. T. s. elegans eggs were incubated under different temperature and moisture regimes. We monitored embryonic development until stage 22 (after sex determination) and, for the first time, we estimated sex ratios using a male-specific transcriptional molecular marker, Sox9...
November 28, 2017: Zoology: Analysis of Complex Systems, ZACS
Marie Altmanová, Michail Rovatsos, Martina Johnson Pokorná, Milan Veselý, Florian Wagner, Lukáš Kratochvíl
Once believed to be restricted only to endotherms (mammals and birds), several poikilothermic amniote lineages have recently been documented to possess long-term evolutionary stability in their sex chromosomes. However, many important lineages were not included in these tests. Previously, based on molecular evidence, we documented the homology of well-differentiated sex chromosomes among seven families of iguanas (Pleurodonta), with basilisks (Corytophanidae) being the only exception, as the tested genes linked to X, but missing on the Y chromosome, in other iguanas were autosomal or pseudoautosomal in basilisks...
November 22, 2017: Zoology: Analysis of Complex Systems, ZACS
Paul M Hampton
As body size increases, some predators eliminate small prey from their diet exhibiting an ontogenetic shift toward larger prey. In contrast, some predators show a telescoping pattern of prey size in which both large and small prey are consumed with increasing predator size. To explore a functional explanation for the two feeding patterns, I examined feeding effort as both handling time and number of upper jaw movements during ingestion of fish of consistent size. I used a range of body sizes from two snake species that exhibit ontogenetic shifts in prey size (Nerodia fasciata and N...
November 21, 2017: Zoology: Analysis of Complex Systems, ZACS
Piter Kehoma Boll, Ana Maria Leal-Zanchet
Land planarians have a simple anatomy and simple behavioral repertoire in relation to most bilaterian animals, which makes them adequate for the study of biological processes. In this study, we investigate the behavior of land planarians during interaction events with other invertebrates found in the same environment. We observed 16 different behavioral units, including seven different capture behaviors and three different prey ingestion behaviors. The capture behavior varied from very simple, such as simply covering the prey with the body, to more complex ones, including two forms of tube formation that are described for the first time...
November 16, 2017: Zoology: Analysis of Complex Systems, ZACS
Piotr Świątek, Pierre de Wit, Natalia Jarosz, Łukasz Chajec, Anna Z Urbisz
The genus Grania comprises over 70 species of exclusively marine clitellate annelids belonging to the family Enchytraeidae. Morphologically, this genus is well separated from other enchytraeids, with thick cuticles, anterior segments I-IV fused into a "head", chaetal bundles consisting only of one stout chaeta, and reduction of circular musculature. The aim of the present study is to describe the ovary organization and the course of oogenesis in Grania postclitellochaeta, and to compare it with other known systems of ovary organization and oogenesis in clitellate annelids, especially in enchytraeids...
November 14, 2017: Zoology: Analysis of Complex Systems, ZACS
Molly E Grear, Michael R Motley, Stephanie B Crofts, Amanda E Witt, Adam P Summers, Petra Ditsche
The skin and blubber of marine mammals provides protection from the surrounding environment, whether that be temperature, microbes, or direct mechanical impacts. To understand the ability of harbor seals' (Phoca vitulina) skin and blubber to resist blunt force trauma, we tested the material properties of these tissues. We quantified two mechanical properties of the tissue: tensile strength and tensile stiffness, at two test speeds, three sample orientations, and two age groups. We found significant differences in material properties between test speeds, orientation, and age of the animal, but did not find a large difference with orientation...
November 11, 2017: Zoology: Analysis of Complex Systems, ZACS
Raf Claes, Pieter G G Muyshondt, Joris J J Dirckx, Peter Aerts
Static pressure changes can alter the configuration and mechanical behavior of the chain of ossicles, which may affect the acoustic transfer function. In mammals, the Eustachian tube plays an important role in restoring ambient middle ear pressure, hence restoring the acoustic transfer function and excluding barotrauma of the middle and inner ear. Ambient pressure fluctuations can be potentially extreme in birds and due to the simple structure of the avian middle ear (one ossicle, one muscle), regulation of the middle ear pressure via reflexive opening of the pharyngotympanic tube appears all the more important...
November 7, 2017: Zoology: Analysis of Complex Systems, ZACS
Parvez Alam, Immanuel Sanka, Lilja Piuli Alam, Saka Wijaya, Erly Sintya, Niken Satuti Nur Handayani, Adolfo Rivero-Müller
The dactyl plunger of Alpheus sp. was found to be a layered composite, with mineral-rich outer and inner layers and a chitin-rich middle layer of high porosity. The chitin-rich middle layer is itself composed of several porous chitin laminae. Modelling heat conduction through the plunger cross-section revealed that the chitin-rich layer is able to insulate heat and retard its progress through the material. Heat accumulates in the plunger after a series of successive snaps and as such, its thermally resistant design can be considered most useful under the conditions of successive snapping...
November 7, 2017: Zoology: Analysis of Complex Systems, ZACS
Shelby B Creager, Marianne E Porter
In sharks, the skin is a biological composite with mineralized denticles embedded within a collagenous matrix. Swimming performance is enhanced by the dermal denticles on the skin, which have drag reducing properties produced by regional morphological variations and changes in density along the body. We used mechanical testing to quantify the effect of embedded mineralized denticles on the quasi-static tensile properties of shark skin to failure in four coastal species. We investigated regional differences in denticle density and skin properties by dissecting skin from the underlying fascia and muscle at 10 anatomical landmarks...
October 31, 2017: Zoology: Analysis of Complex Systems, ZACS
Karin B Holthaus, Lorenzo Alibardi
Corneous beta-proteins (CBPs), formerly referred to as beta-keratins, are major protein components of the epidermis in lepidosaurian reptiles and are largely responsible for their material properties. These proteins have been suggested to form filaments of 3.4nm in thickness and to interact with themselves or with other proteins, including intermediate filament (IF) keratins. Here, we performed immunocytochemical labeling of CBPs in the epidermis of different lizards and snakes and investigated by immunoblotting analysis whether the reduction of disulfide bonds or protein oxidation affects the solubility and mobility of these CBPs...
October 29, 2017: Zoology: Analysis of Complex Systems, ZACS
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"