Odysseys in Pastryland – a bird’s eye view of microevolution

Theory based models of microevolutionary processes are difficult to test in the wild, because the data relating to the specific predictions of the model must be disentangled from the complexity of the species’ overall ecology. Since the 1960s some evolutionary ecologists have been using field experiments involving artificial prey and wild predators – the ecology of the ‘prey’ is under the control of the experimenter, which greatly simplifies the logistics of testing specific microevolutionary models. So far, this technique – typically using prey ‘worms’ made from pastry and wild passerine birds as predators – has been used to test theoretical models of crypsis, directional vs. stabilising selection, apostatic selection, polymorphism, and mimicry systems (Allen, Cooper, Hall, and McHenry 1993). To date, the ‘Pastryland’ technique has been used by ecologists at the Universities of Reading and Southampton in the UK.Because it is a simple model of microevolution in the real world, and because individual experiments rarely require more than a few days to complete, ‘Pastryland’ has also been used to demonstrate the process of natural selection to tertiary science students (Allen, Cooper, Hall, and McHenry 1993). Natural selection is a powerful but very subtle theory, and is hard to grasp without some sort of real world demonstration or example. The logistics of Pastryland experiments mean that it can easily be performed as part of a tertiary field-based activity, with students intimately involved with the running of the experiment. Students are immersed in evolution by taking an active role in the process. Although the pastry ‘prey’ are artificial, the technique relies ultimately on the behaviour of wild predators, as a ‘real’ selective pressure, enhancing student concept acquisition in evolutionary theory. Pastryland was trialed as a group field project for third year ecology undergraduates at the University of Newcastle. They tested a specific prediction about the dynamics of mimicry systems that has not yet been tested experimentally. This was the first time (to our knowledge) that Pastryland has been used within a teaching context in Australia, and we adapted the technique to make use of common wild birds in Australian urban environments. In the UK, the most important predator was the blackbird (Turdus merula) – in coastal NSW, the main predators are noisy miners (Manorina melanocephala), magpies (Gymnorhina tibicen), and currawongs (Strepera graculina). Students also modified the experimental design to improve controls, and involved local high schools in the hope that the technique would ‘catch-on’ with science teachers

An interactive three dimensional approach to anatomical description—the jaw musculature of the Australian laughing kookaburra (Dacelo novaeguineae)

The investigation of form-function relationships requires a detailed understanding of anatomical systems. Here we document the 3-dimensional morphology of the cranial musculoskeletal anatomy in the Australian Laughing Kookaburra Dacelo novaeguineae, with a focus upon the geometry and attachments of the jaw muscles in this species. The head of a deceased specimen was CT scanned, and an accurate 3D representation of the skull and jaw muscles was generated through manual segmentation of the CT scan images, and augmented by dissection of the specimen. We identified 14 major jaw muscles: 6 in the temporal group (M. adductor mandibulae and M. pseudotemporalis), 7 in the pterygoid group (M. pterygoideus dorsalis and M. pterygoideus ventralis), and the single jaw abductor M. depressor mandibulae. Previous descriptions of avian jaw musculature are hindered by limited visual representation and inconsistency in the nomenclature. To address these issues, we: (1) present the 3D model produced from the segmentation process as a digital, fully interactive model in the form of an embedded 3D image, which can be viewed from any angle, and within which major components can be set as opaque, transparent, or hidden, allowing the anatomy to be visualised as required to provide a detailed understanding of the jaw anatomy; (2) provide a summary of the nomenclature used throughout the avian jaw muscle literature. The approach presented here provides considerable advantages for the documentation and communication of detailed anatomical structures in a wide range of taxa

Increasing Dietary Breadth Through Allometry: Bite Forces in Sympatric Australian Skinks

Ecomechanical measures of performance such as bite force may function as an indirect measure of niche. This study proposes that allometric changes in performance may contribute to niche separation, especially in a group where the specific mechanism(s) remains unclear. We surveyed the bite force and morphology of 5 wild caught, sympatric skink species in the Kimberley region of Western Australia. Skinks were collected from trapline fences, weighed, photographed, and maximum bite force was measured with a piezoresistive force sensor. Morphological metrics were derived from photographs of the dorsum. Normalized morphological traits indicate interspecific variability in form, particularly in forelimb length, which may be a result of habitat separation. Bite force showed strong, significantly positive, allometric scaling against most morphological traits. Tail length was the only morphological trait that scaled isometrically. Allometric changes in bite force may increase dietary breadth, allowing larger skinks to supplement their diet with larger, more durable prey. This study reveals that ecologically relevant traits may be explained by allometric differences coupled with size variation. Future work should focus on (1) an increase in sample size, (2) long-term measurement of diet selection, and (3) accessibility of prey items to our focal animals

Kontrol Diri Dan Kecemasan Komunikasi Interpersonal Pada Pramuwisata

This study aim to analysis relationship of self-control and anxiety of interpersonal communicationin a tourist guide. Product moment corelation analysis (rxy) yields for 0905, to provethe relationship between self-control and interpersonal communication anxiety in a tourist guide.These results indicate a negative relationship between the variables X (Self Control) and variableY (Interpersonal Communication Anxiety in the guides). Social Learning Theory became atheories used in this study, where most of the individual behavior acquired partly the result oflearning through observation of behavior displayed other individuals whose became the model.Elaboration Likelihood Theory which states that each individual will interpret the message orinformation they receive, in accordance with the information they have and their beliefs aboutsomething related to the message. Self-control on the tour guides in Yogyakarta based on thefive major aspects of self-control, that has a very high level of measurement. Includes the abilityto anticipate events, the ability to interpret events and the ability to take decisions. Meanwhile,two other aspects of self control shows the results of measurements at very low category, whichconsists of aspects of behavior and stimulus control. While anxiety based on the three aspects ofinterpersonal communication, which consists of inhibition of the ability to express themselves,lack of interest in communicating and social interaction is interrupted, it indicates the levelmeasurement at very low category. Thus, interpersonal communication anxiety on tour guidesin Yogyakarta can be said to be very low

Varanus Panoptes (Yellow-Spotted Monitor) Toxic Prey Avoidance

Although large predatory animals are capable of capturing and consuming large prey, most regularly consume smaller prey (e.g., Hart and Hamrin 1990. In Hughes [ed.], Behavioural Mechanisms of Food Selection, pp. 235–253. Springer-Verlag, Berlin). Large monitor lizards are no exception. For example, Varanus bengalensis reaches 1.75 m in total length but 75% of its diet consists of small invertebrates (Auffenberg 1994. The Bengal Monitor. The University Press of Florida, Gainesville. 560 pp.). Generalist predators such as large monitor lizards use different foraging strategies to obtain different prey, a pattern well documented for V. bengalensis (Auffenberg 1994, op. cit.). One foraging behaviour noted was regular searches for dung beetles (Scarabaeidae) in the dung pats of (mainly) large mammals. Herein we document similar foraging behaviour in the Yellow-spotted Monitor, Varanus panoptes, in northern Australi

From Single Neurons to Behavior in the Jellyfish Aurelia aurita

Jellyfish nerve nets provide insight into the origins of nervous systems, as both their taxonomic position and their evolutionary age imply that jellyfish resemble some of the earliest neuron-bearing, actively-swimming animals. Here we develop the first neuronal network model for the nerve nets of jellyfish. Specifically, we focus on the moon jelly Aurelia aurita and the control of its energy-efficient swimming motion. The proposed single neuron model disentangles the contributions of different currents to a spike. The network model identifies factors ensuring non-pathological activity and suggests an optimization for the transmission of signals. After modeling the jellyfish's muscle system and its bell in a hydrodynamic environment, we explore the swimming elicited by neural activity. We find that different delays between nerve net activations lead to well-controlled, differently directed movements. Our model bridges the scales from single neurons to behavior, allowing for a comprehensive understanding of jellyfish neural control

Oldest pathology in a tetrapod bone illuminates the origin of terrestrial vertebrates

The origin of terrestrial tetrapods was a key event in vertebrate evolution, yet how and when it occurred remains obscure, due to scarce fossil evidence. Here, we show that the study of palaeopathologies, such as broken and healed bones, can help elucidate poorly understood behavioural transitions such as this. Using high-resolution finite element analysis, we demonstrate that the oldest known broken tetrapod bone, a radius of the primitive stem tetrapod Ossinodus pueri from the mid-Viséan (333 million years ago) of Australia, fractured under a high-force, impact-type loading scenario. The nature of the fracture suggests that it most plausibly occurred during a fall on land. Augmenting this are new osteological observations, including a preferred directionality to the trabecular architecture of cancellous bone. Together, these results suggest that Ossinodus, one of the first large (>2m length) tetrapods, spent a significant proportion of its life on land. Our findings have important implications for understanding the temporal, biogeographical and physiological contexts under which terrestriality in vertebrates evolved. They push the date for the origin of terrestrial tetrapods further back into the Carboniferous by at least two million years. Moreover, they raise the possibility that terrestriality in vertebrates first evolved in large tetrapods in Gondwana rather than in small European forms, warranting a re-evaluation of this important evolutionary event

The Effects of Biting and Pulling on the Forces Generated during Feeding in the Komodo Dragon (Varanus komodoensis)

In addition to biting, it has been speculated that the forces resulting from pulling on food items may also contribute to feeding success in carnivorous vertebrates. We present an in vivo analysis of both bite and pulling forces in Varanus komodoensis, the Komodo dragon, to determine how they contribute to feeding behavior. Observations of cranial modeling and behavior suggest that V. komodoensis feeds using bite force supplemented by pulling in the caudal/ventrocaudal direction. We tested these observations using force gauges/transducers to measure biting and pulling forces. Maximum bite force correlates with both body mass and total body length, likely due to increased muscle mass. Individuals showed consistent behaviors when biting, including the typical medial-caudal head rotation. Pull force correlates best with total body length, longer limbs and larger postcranial motions. None of these forces correlated well with head dimensions. When pulling, V. komodoensis use neck and limb movements that are associated with increased caudal and ventral oriented force. Measured bite force in Varanus komodoensis is similar to several previous estimations based on 3D models, but is low for its body mass relative to other vertebrates. Pull force, especially in the ventrocaudal direction, would allow individuals to hunt and deflesh with high success without the need of strong jaw adductors. In future studies, pull forces need to be considered for a complete understanding of vertebrate carnivore feeding dynamics

The effect of spine postures on the hydrodynamic drag in Epinephelus ongus larvae

Laboratory behavioural observation and computational fluid dynamics (CFD) analysis were conducted to examine whether the movement of the elongated dorsal and pelvic spines changed the hydrodynamic drag in white-streaked grouper Epinephelus ongus larvae. The behavioural observation in the tank revealed that the larvae extended the dorsal and pelvic spines during passive transport and retracted during swimming; the angles of the dorsal and pelvic spines in relation to the anteroposterior axis were larger during the passive transport (mean±s.d. = 28・84±14・27 and 20・35±15・05°) than those during the swimming (mean±s.d. = 2・59±5・55 and 0・32±6・49°). The CFD analysis indicated that the relative hydrodynamic drag acting on the larvae was approximately 1・25 times higher when the spines were extended (passive transport) than when the spines were retracted (swimming), suggesting that the E. ongus larvae have an ability to adjust their hydrodynamic drag depending on the behavioural context. Journal of Fish Biolog