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T Getty

Publications and source records attributed to T Getty.

6 recordsLinked to original sources
PubMed2000

Colour, fat and social status in male damselflies, Calopteryx maculata.

In the black-winged damselfly, Calopteryx maculata, younger males challenge and displace older males from mating territories. Fatter males tend to win fights. These fights were initially interpreted as wars of attrition based on fat reserves, but the distributions of fat at the end of fights suggests at least some assessment of the opponent's condition. Alternatively, new models have been developed that show how the observed pattern could result without assessment. We show that there is a subtle but reliable cue to fat reserves: colour. Females are a relatively drab brown-black. Males are a strikingly iridescent blue-green colour, resulting from a multilayer constructive interference reflector system in the epicuticle. In fatter males the lamellae are more compressed and the peak reflectance is at shorter wavelengths (blue). Leaner, greener males have greater spacing between lamellae and reflect longer wavelengths. The peak reflectance is as predicted from transmission electron micrograph measurements of the lamellar spacing. The rate of change in spacing over time can be manipulated experimentally by manipulating the diet. Individuals on a higher food diet remained blue longer and at the end of the experiment were fatter and bluer. In our studies, colour is a better predictor of territorial status than fat. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Handicap signalling: when fecundity and viability do not add up.

It is widely accepted that a requirement for honest handicap signalling is that higher-quality signallers pay lower marginal costs for advertising. This is a simple, powerful principle, but it is correct only if the fitness effects of fecundity and viability are strictly additive. Additivity would not be expected from most life history models. The general criterion for honest handicap signalling is that higher-quality signallers must have higher marginal fitness effects of advertising. This might result from higher benefits rather than lower costs. The general criterion implies the existence of a ridge on the fitness surface for two correlated characters, quality (or viability) and advertising. This has important implications for the design of experiments. Critical tests of the handicap hypothesis should establish that signallers of different quality are on a rising fitness ridge because of different cost-benefit trade-offs. The further question of whether receivers are maximizing their fitness requires additional experiments because handicap signalling does not require that the receivers maximize their fitness, only that they return benefits to signallers as an increasing function of the size of the signal. If receiver preferences are exaggerated by sensory bias or indirect selection, the resulting exaggerated signals may be consistent with the handicap principle. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1997

Modulation of behavioral and neurochemical measures of forebrain dopamine function in mice by species-specific interleukin-2.

Interleukin-2 (IL-2) has recently been implicated as a modulator of brain neuronal function and in the pathogenesis of several major neuropsychiatric disorders involving the dopamine system (e.g. schizophrenia and Parkinson's disease). Little is known, however, about the effects of IL-2 on dopamine-mediated behaviors. A series of behavioral experiments were performed in mice to examine the hypothesis that species-specific IL-2 could modify behaviors known to be mediated by forebrain dopamine pathways. IL-2 administered subcutaneously produced a robust increase in locomotor activity in an elevated plus-maze. No effects of the cytokine were evident on measures of acoustic startle, prepulse inhibition of the startle response (PPI), or fearfulness. In complementary in vitro neurochemical experiments, to most closely assess physiologically relevant effects of the cytokine on dopamine release from striatal neurons, species-specific IL-2 as well as high performance liquid chromatography (HPLC) were used to measure endogenous dopamine release from striatal slices. IL-2 dose-dependently modulated veratrine-evoked release of endogenous dopamine in a biphasic pattern, increasing release at lower concentrations and inhibiting release at a high concentration of the cytokine. In radioligand competition binding experiments, IL-2 was not active at striatal binding sites for [3H]spiroperidol (D2-like receptors), [3H]mazindol binding (dopamine uptake sites) and [3H]SCH23390 (D1-like receptors), indicating that the neuromodulatory actions of IL-2 are not the result of direct or allosteric effects on dopamine receptors. Knowledge of the mechanisms by which IL-2 influences brain dopamine function could provide new insight into the pathophysiology of forebrain dopamine neurons seen in disorders such as Parkinson's disease and schizophrenia.

Acoustic Stimulation↗