Open Access. Powered by Scholars. Published by Universities.®

Organisms Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 13 of 13

Full-Text Articles in Organisms

Microhabitat Use Affects Goby (Gobiidae) Cue Choice In Spatial Learning Task, G. E. White, C. Brown Sep 2016

Microhabitat Use Affects Goby (Gobiidae) Cue Choice In Spatial Learning Task, G. E. White, C. Brown

Culum Brown, PhD

This study investigated whether spatial learning ability and cue use of gobies (Gobiidae) from two contrasting habitats differed in a spatial task. Gobies were collected from the spatially complex rock pools and dynamic, homogenous sandy shores. Fishes were trained to locate a shelter under the simulated threat of predation and it was determined whether they used local or extra-maze (global) and geometric cues to do so. It was hypothesized that fishes from rock pools would outperform fishes from sandy shores in their ability to relocate shelter and the two groups would differ in their cue use. It was found that …


Predator Recognition And Responses In The Endangered Macquarie Perch (Macquaria Australasica), Culum Brown, Jennifer Morgan Sep 2016

Predator Recognition And Responses In The Endangered Macquarie Perch (Macquaria Australasica), Culum Brown, Jennifer Morgan

Culum Brown, PhD

Macquarie perch, Macquaria austalasica, is an endangered species endemic to southern Australia whose distribution is highly fragmented and continues to decline. Key threatening processes include habitat destruction, dams and weirs, overfishing and interactions with introduced species. Here, we examined the responses of small and large Macquarie perch to two native predators and to the introduced redfin perch, Perca fluviatilis. Our results showed that Macquarie perch generally avoided large-bodied native predators but was attracted to small-bodied native predators. Responses to large and small redfin perch lay between these two extremes, suggesting that the Macquarie perch does treat these foreign fish as …


Laterality Enhances Numerical Skills In The Guppy, Poecilia Reticulata, Marco Dadda, Christian Agrillo, Angelo Bisazza, Culum Brown Sep 2016

Laterality Enhances Numerical Skills In The Guppy, Poecilia Reticulata, Marco Dadda, Christian Agrillo, Angelo Bisazza, Culum Brown

Culum Brown, PhD

It has been hypothesized that cerebral lateralization can significantly enhance cognition and that this was one of the primary selective forces shaping its wide-spread evolution amongst vertebrate taxa. Here, we tested this hypothesis by examining the link between cerebral lateralization and numerical discrimination. Guppies, Poecilia reticulata, were sorted into left, right and non-lateralized groups using a standard mirror test and their numerical discrimination abilities tested in both natural shoal choice and abstract contexts. Our results show that strongly lateralized guppies have enhanced numerical abilities compared to non-lateralized guppies irrespective of context. These data provide further credence to the notion that …


A Comparison Of Spatial Learning And Memory Capabilities In Intertidal Gobies, Gemma E. White, Culum Brown May 2016

A Comparison Of Spatial Learning And Memory Capabilities In Intertidal Gobies, Gemma E. White, Culum Brown

Culum Brown, PhD

For the majority of animals, the ability to orient in familiar locations is a fundamental part of life, and spatial memory allows individuals to remember key locations such as food patches, shelter, mating sites or areas regularly occupied by predators. This study determined if gobies collected from rocky platforms and sandy beaches differ in their ability to learn and memorise the locations of tide pools in a simulated rocky intertidal zone. Intertidal rock pool gobies show acute homing abilities and, therefore, should be expected to display superior learning and memory capabilities. In contrast, it is unlikely that natural selection would …


Microhabitat Use Affects Brain Size And Structure In Intertidal Gobies, Gemma E. White, Culum Brown May 2016

Microhabitat Use Affects Brain Size And Structure In Intertidal Gobies, Gemma E. White, Culum Brown

Culum Brown, PhD

The ecological cognition hypothesis poses that the brains and behaviours of individuals are largely shaped by the environments in which they live and the associated challenges they must overcome during their lives. Here we examine the effect of environmental complexity on relative brain size in 4 species of intertidal gobies from differing habitats. Two species were rock pool specialists that lived on spatially complex rocky shores, while the remainder lived on dynamic, but structurally simple, sandy shores. We found that rock pool-dwelling species had relatively larger brains and telencephalons in particular, while sand-dwelling species had a larger optic tectum and …


Influence Of Rock-Pool Characteristics On The Distribution And Abundance Of Inter-Tidal Fishes, Gemma E. White, Grant C. Hose, Culum Brown May 2016

Influence Of Rock-Pool Characteristics On The Distribution And Abundance Of Inter-Tidal Fishes, Gemma E. White, Grant C. Hose, Culum Brown

Culum Brown, PhD

Rock pools can be found in inter-tidal marine environments worldwide; however, there have been few studies exploring what drives their, fish species composition, especially in Australia. The rock-pool environment is highly dynamic and offers a unique natural laboratory to study the habitat choices, physiological limitations and adaptations of inter-tidal fish species. In this study rock pools of the Sydney region were sampled to determine how the physical (volume, depth, rock cover and vertical position) and biological (algal cover and predator presence) parameters of pools influence fish distribution and abundance. A total of 27 fish species representing 14 families was observed …


Personality Affects Learning And Trade-Offs Between Private And Social Information In Guppies, Poecilia Reticulate, Larissa Trompf, Culum Brown May 2016

Personality Affects Learning And Trade-Offs Between Private And Social Information In Guppies, Poecilia Reticulate, Larissa Trompf, Culum Brown

Culum Brown, PhD

The acquisition of information such as the location and quality of food, mates or shelter is a key survival requirement for animals. Individuals can acquire information through personal experience (private information) or through observing and interacting with others (social information). Environmental spatial and temporal heterogeneity can mean that sometimes social information conflicts with private knowledge. We tested how personality affected the importance placed on public versus private information in wild female guppies when these two information sources came into conflict. We found that boldness and sociality affected decisions to use conflicting social and private information. Bolder females used social information …


Variation In Brain Morphology Of Intertidal Gobies: A Comparison Of Methodologies Used To Quantitatively Assess Brain Volumes In Fish, Gemma E. White, Culum Brown May 2016

Variation In Brain Morphology Of Intertidal Gobies: A Comparison Of Methodologies Used To Quantitatively Assess Brain Volumes In Fish, Gemma E. White, Culum Brown

Culum Brown, PhD

When correlating brain size and structure with behavioural and environmental characteristics, a range of techniques can be utilised. This study used gobiid fishes to quantitatively compare brain volumes obtained via three different methods; these included the commonly used techniques of histology and approximating brain volume to an idealised ellipsoid, and the recently established technique of X-ray micro-computed tomography (micro-CT). It was found that all three methods differed significantly from one another in their volume estimates for most brain lobes. The ellipsoid method was prone to over- or under-estimation of lobe size, histology caused shrinkage in the telencephalon, and although micro-CT …


Learning And Memory In The Port Jackson Shark, Heterodontus Portusjacksoni, Tristan L. Guttridge, Culum Brown May 2016

Learning And Memory In The Port Jackson Shark, Heterodontus Portusjacksoni, Tristan L. Guttridge, Culum Brown

Culum Brown, PhD

Basic understanding of the fundamental principles and mechanisms involved in learning is lacking for elasmobranch fishes. Our aim in this study was to experimentally investigate the learning and memory capacity of juvenile Port Jackson sharks, Heterodontus portusjacksoni. Sharks (N = 30) were conditioned over a 19-day period to associate an underwater LED light or stream of air-bubbles [conditioned stimulus (CS)] with a food reward [unconditioned stimulus (US)], using three procedures (delay, trace and control). During experiments, the CS signalled at a random time between 180 and 300 s for 30 s (six times per day). For the delay the US …


Fish Intelligence, Sentience And Ethics, Culum Brown May 2016

Fish Intelligence, Sentience And Ethics, Culum Brown

Culum Brown, PhD

Fish are one of the most highly utilised vertebrate taxa by humans; they are harvested from wild stocks as part of global fishing industries, grown under intensive aquaculture conditions, are the most common pet and are widely used for scientific research. But fish are seldom afforded the same level of compassion or welfare as warm-blooded vertebrates. Part of the problem is the large gap between people’s perception of fish intelligence and the scientific reality. This is an important issue because public perception guides government policy. The perception of an animal’s intelligence often drives our decision whether or not to include …


Laterality Is Linked To Personality In The Black-Lined Rainbowfish, Melanotaenia Nigrans, Culum Brown, Anne-Laurence Bibost May 2016

Laterality Is Linked To Personality In The Black-Lined Rainbowfish, Melanotaenia Nigrans, Culum Brown, Anne-Laurence Bibost

Culum Brown, PhD

Emotions such as fear in vertebrates are often strongly lateralised, that is, a single cerebral hemisphere tends to be dominant when processing emotive stimuli. Boldness is a measure of an individual’s propensity to take risks and it has obvious connections with fear responses. Given the emotive nature of this well-studied personality trait, there is good reason to suspect that it is also likely to be expressed in a single hemisphere. Here, we examined the link between laterality and boldness in wild and captive-reared rainbowfish, Melanotaenia nigrans. We found that fish from the wild were bolder than those from captivity, which …


Laterality Influences Cognitive Performance In Rainbowfish Melanotaenia Duboulayi, Anne-Laurence Bibost, Culum Brown May 2016

Laterality Influences Cognitive Performance In Rainbowfish Melanotaenia Duboulayi, Anne-Laurence Bibost, Culum Brown

Culum Brown, PhD

Cerebral lateralization has been suggested to convey a selective advantage to individuals by enhancing their cognitive abilities. Few, however, have explicitly compared the cognitive ability of animals with strongly contrasting laterality. Here, we examined the influence of laterality on learning performance in the crimson spotted rainbowfish, Melanotaenia duboulayi, using a classical conditioning paradigm. We also compared the learning ability of wild caught and captive-reared fish to examine the influence of rearing environment on cognitive performance. Laterality was established by observing which eye fish preferred to use while viewing their mirror image. Subjects were then conditioned to associate the appearance of …


Cue Choice And Spatial Learning Ability Are Affected By Habitat Complexity In Intertidal Gobies, Gemma E. White, Culum Brown May 2016

Cue Choice And Spatial Learning Ability Are Affected By Habitat Complexity In Intertidal Gobies, Gemma E. White, Culum Brown

Culum Brown, PhD

Variation in the structural complexity of a habitat is known to have significant affects on the evolution of different populations and can shape behavior, morphology, and life-history traits. Here, we investigated whether habitat complexity influences a species’ capacity for spatial learning and cue choice by comparing the performance of 4 goby species from 2 contrasting habitats in a spatial task. Gobies were collected from dynamic, homogenous sandy shores and stable, spatially complex rock pool habitats. We trained fish to use a T-maze to find a hidden reward and asked whether they used local visual landmarks or body-centered methods for orientation …