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Zoology: Analysis of Complex Systems, ZACS

Luiz Silva, Paulo Lana
In this paper, we have experimentally assessed tube-building strategies of Owenia caissaraSilva & Lana, 2017, including the particle size preferences. After acclimation, individual tubes were broken by their mid-region, and placed in experimental aquaria with four types of homogeneous substrates (from silt-clay to coarse sand) and four types of mixed substrates. Animals completely removed from their tubes were unable to build new tubes. Adults in broken tubes were able to use a wide range of particles, from fine to coarse sand, but not silt-clay...
August 2018: Zoology: Analysis of Complex Systems, ZACS
María V Fernandez Blanco, Guillermo H Cassini, Paula Bona
Ontogenetic variation of cranial characters used in crocodylian phylogenetic systematics has never been studied. Furthermore, the relationship between diet and skull morphological transformation during ontogeny has not been properly explored yet. We quantify the inter- and intraspecific skull morphological variation in extant caiman species focusing on those areas relevant to systematics and, also investigate the relation between diet and morphological changes during ontogeny. We applied a three-dimensional approach of geometric morphometrics on post-hatching ontogenetic cranial series of Caiman latirostris and C...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Stephen D Atkinson, Jerri L Bartholomew, Tamar Lotan
Myxozoans are endoparasites with complex life cycles that alternate between invertebrate and vertebrate hosts. Though considered protozoans for over 150 years, they are now recognized as metazoans, given their multicellularity and ultrastructural features. In recognition of synapomorphies and cnidarian-specific genes, myxozoans were placed recently within the phylum Cnidaria. Although they have lost genetic and structural complexity on the path to parasitism, myxozoans have retained characteristic cnidarian cnidocysts, but use them for initiating host infection...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Alexus S Roberts, Stacy C Farina, Reuben R Goforth, Nicholas J Gidmark
Vertebrate lever mechanics are defined by the morphology of skeletal elements and the properties of their muscular actuators; these metrics characterize functional diversity. The components of lever systems work in coordination ("functional integration") and may show strong covariation across evolutionary history ("evolutionary integration"), both of which have been hypothesized to constrain phenotypic diversity. We quantified evolutionary integration in a functionally integrated system - the lower jaw of sculpins and relatives (Actinopterygii: Cottoidei)...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Amanda M Herbert, Philip J Motta
Durophagy in chondrichthyan fishes is thought to entail a set of morphological characteristics, such as hypertrophied adductor muscles, molariform teeth, and high bite forces. However, these characteristics are not common to all durophagous chondrichthyans. In some durophagous chondrichthyans, the jaws are better suited biomechanically to resist bending in the area where prey is processed. Resistance to bending is in part, quantified by second moment of area (I), which uses the neutral axis of an object to analyze the arrangement of material...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Ken S Toyama, Karina Junes, Jorge Ruiz, Alejandro Mendoza, Jose M Pérez
Ontogenetic shifts from an insectivorous diet towards an herbivorous one are well known in lizards. Energetic, behavioral and morphological factors have been linked to this pattern, but the latter have received less attention, especially with respect to head morphology. It is known that robust heads are related to stronger bite forces, consequently facilitating the consumption of harder or tougher, more fibrous items such as plants. In this study the ontogeny of diet and head morphology of the omnivorous tropidurid lizard Microlophus thoracicus are described...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Falk Mielke, Vivian Schunke, Jan Wölfer, John A Nyakatura
In in-vivo motion analyses, data from a limited number of subjects and trials is used as proxy for locomotion properties of entire populations, yet the inherent hierarchy of the individual and population level is usually not accounted for. Despite the increasing availability of hierarchical model frameworks for statistical analyses, they have not been applied extensively to comparative motion analysis. As a case study for the use of hierarchical models, we analyzed locomotor parameters of four Swinhoe's striped squirrels...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Davide Tamagnini, Jamie Stephenson, Richard P Brown, Carlo Meloro
The non-venomous grass snake (Natrix helvetica) and the venomous adder (Vipera berus) are two native species that are often found in sympatry in Great Britain and Europe. They occupy partially overlapping ecological niches and prey on small vertebrates, but use different feeding strategies. Here, we investigated the morphologies of grass snakes and adders from Dorset (UK) using two-dimensional geometric morphometrics to assess the degree of sexual dimorphism in size and shape together with the relative impact of allometry and general body dimensions on head shape...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Welton Dionisio-da-Silva, André Felipe de Araujo Lira, Cleide Maria Ribeiro de Albuquerque
Edge effects have drastically affected species living in tropical forests. However, understanding how species respond to edge effects remains a challenge, owing to the many factors involved and different responses of each species thereto. Here, we analyzed how the abundance of two sympatric scorpion species (Tityus pusillus and Ananteris mauryi) and their potential prey varied as a function of microhabitat changes (litter depth, dry mass, and leaf shape) from edge to interior forest habitats. We further analyzed the contribution of potential prey to scorpion abundance and reproductive periods...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Tim Caro, Victoria M Morgan
Color polymorphisms are widespread in nature and can be maintained by several evolutionary processes. We used the coconut crab (Birgus latro) red/blue color polymorphism as a test case to explore the functional significance of intraspecific variation in crab coloration. Across our study sites on Pemba and Chumbe Islands, Tanzania, and Christmas Island, Australian Territory, red:blue morph ratios were 76.5%, 66.7% and 72.0% respectively, or approximately 3:1 in each case. To investigate whether coloration is sex or size dependent, signals strength or behavior, or is a physiological pleiotropic effect, we measured body weights, linear dimensions, pinch-force, behavioral dispositions and took crude environmental variables in the field...
August 2018: Zoology: Analysis of Complex Systems, ZACS
Giovanni Bearzi, Dan Kerem, Nathan B Furey, Robert L Pitman, Luke Rendell, Randall R Reeves
The scientific study of death across animal taxa-comparative thanatology-investigates how animals respond behaviourally, physiologically and psychologically to dead conspecifics, and the processes behind such responses. Several species of cetaceans have been long known to care for, attend to, be aroused by, or show interest in dead or dying individuals. We investigated patterns and variation in cetacean responses to dead conspecifics across cetacean taxa based on a comprehensive literature review. We analysed 78 records reported between 1970 and 2016, involving 20 of the 88 extant cetacean species...
June 2018: Zoology: Analysis of Complex Systems, ZACS
Haruhiko Yasumuro, Yuzuru Ikeda
We investigated the effects of environmental enrichment on the cognitive abilities of pharaoh cuttlefish, Sepia pharaonis, which were reared from day seven in four different environments: isolated, poor, standard, and enriched. First, we used "prawn-in-the-tube" to test whether environmental enrichment affects the ontogeny of learning and memory of S. pharaonis. The results showed that cuttlefish could usually learn the task regardless of their age and environment. At early age (74 - 81 d), cuttlefish from the isolated environment memorized the task for 24h...
June 2018: Zoology: Analysis of Complex Systems, ZACS
Anna Z Urbisz, Łukasz Chajec, Mana Ito, Katsutoshi Ito
In Thalassodrilides cf. briani, the paired ovaries are inconspicuous and polarized structures with developmental gradient of germ cells along their long axis. The about 300 germ cells in the ovary are consolidated into one syncytial cyst and each cell is connected to a common and branched mass of cytoplasm via one stable cytoplasmic bridge. The germ cells differentiate their fate into nurse cells and oocytes. Only one oocyte grows in a given time; it gathers cell organelles and yolk and then it detaches from the gonad...
June 2018: Zoology: Analysis of Complex Systems, ZACS
Katarzyna Wołczuk, Maciej Ostrowski, Agnieszka Ostrowska, Teresa Napiórkowska
The alimentary tract of oxudercine gobies is characterized by a lack of an anatomically distinct stomach, owing to which they are classified as stomachless. Since the environment, food requirements, and feeding habits have a significant impact on the anatomy of the alimentary tract of fish, it was assumed that predominantly carnivorous, semi-terrestrial mudskippers would have a stomach. In order to verify this hypothesis, anatomical, histological, histochemical and ultrastructural analysis of the alimentary tract of the Atlantic mudskipper Periophthalmus barbarus was performed...
June 2018: Zoology: Analysis of Complex Systems, ZACS
André Zehnder, Stephen Henley, Robert Weibel
The central Kalahari region in Botswana is one of the few remaining ecosystems with a stable lion population. Yet, relatively little is known about the ecology of the lions there. As an entry point, home range estimations provide information about the space utilization of the studied animals. The home ranges of eight lions in this region were determined to investigate their spatial overlaps and spatiotemporal variations. We found that, except for MCP, all home range estimators yielded comparable results regarding size and shape...
June 2018: Zoology: Analysis of Complex Systems, ZACS
Hayley J Stannard, Melissa L Tulk, Melissa J Bortolazzo, Julie M Old
Spinifex hopping-mice (Notomys alexis) and plains mice (Pseudomys australis) are able to successfully occupy arid zones of Australia. We studied the digestive parameters and energy assimilation of captive spinifex hopping-mice and plains mice. The experiment consisted of six diets fed to the animals for periods of 12days per food type. On a dry matter basis, the plains mice consumed between 2.5 and 7.2% and the hopping-mice between 5.8 and 9.3% of their body mass in food per day. The body mass of the spinifex hopping-mice increased significantly on the sunflower seed diet, while body mass did not change significantly for the plains mice on any diet...
June 2018: Zoology: Analysis of Complex Systems, ZACS
Noa Katz, Tamar Dayan, Noga Kronfeld-Schor
Many factors affect individual fitness, but while some factors, such as resource availability, have received strong experimental support, others including interspecific competition have rarely been quantified. Nevertheless, interspecific competition is commonly mentioned in the context of reproductive success and fitness. In general, when reproduction is likely to fail, reproductive suppression may occur. We studied the golden spiny mouse (Acomys russatus) and the common spiny mouse (A. cahirinus; however, recent molecular analysis in spiny mice from Jordan and Sinai suggests this species is A...
June 2018: Zoology: Analysis of Complex Systems, ZACS
D A Blank
Compared to solitary species, social ungulates benefit from living in groups not only because of the "many eyes effect", when each individual devotes less time to vigilance and spends more time foraging and engaged in other activities, or of the "dilution effect", when the probability that any specific individual will be caught decreases with herd size, but also because of early alarm signals produced by conspecifics that provide enough time for a successful escape from predator attack. These signals can contain multiple messages about the category of the predator and the degree of risk...
May 18, 2018: Zoology: Analysis of Complex Systems, ZACS
Jonas O Wolff, Braxton Jones, Marie E Herberstein
The nature and size of attachments is a fundamental element of animal constructions. Presumably, these adhesive structures are plastically deployed to balance material investment and attachment strength. Here we studied plasticity in dragline anchorages of the golden orb web spider, Nephila plumipes. Specifically, we predict that spiders adjust the size and structure of dragline anchorages with load, i.e. spider mass. Mass was manipulated by attaching lead pieces to the spider's abdomen resulting in a 50 percent increase in mass...
May 17, 2018: Zoology: Analysis of Complex Systems, ZACS
Chunmian Zhang, Tinglei Jiang, Guanjun Lu, Aiqing Lin, Keping Sun, Sen Liu, Jiang Feng
Evolutionary biologists had a long-standing interest in the evolutionary forces underlying geographical variation in the acoustic signals of animals. However, the evolutionary forces driving acoustic variation are still unclear. In this study, we quantified the geographical variation in the peak frequencies of echolocation calls in eight Miniopterus fuliginosus bat colonies, and assessed the forces that drive acoustic divergence. Our results demonstrated that seven of the colonies had very similar peak frequencies, while only one colony was significantly higher than the others...
May 12, 2018: Zoology: Analysis of Complex Systems, ZACS
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