J.-O Lachaud

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We describe a technique based on automatic photography as an alternative to the visual scanning method for behavioural investigations of insect societies. This technique opens up the possibilities for studying poorly-populated colonies over prolonged periods. The reliability of this technique as compared to the direct observational method was demonstrated(More)
Within the theoretical framework of adaptive significance, it is often claimed that insects learn just what they are genetically programmed to learn. Consequently, because of the alleged lack of plasticity of their behaviour, many learning tests applied to insects are limited to very simple associative Stimulus-Response research paradigms. If the(More)
A model of individual foraging in social insects as presented that formalises the dynamics of foraging and concentrates on the collective rather than the individual benefit, quantifying the relationships between a colony's foraging area, number of foragers and foraging energy budget and the food sources' rate of arrival, disappearance and capture. A series(More)
The analysis of digital shapes require tools to determine accurately their geometric characteristics. Their boundary is by essence discrete and is seen by continuous geometry as a jagged continuous curve, either straight or not derivable. Discrete geometric estimators are specific tools designed to determine geometric information on such curves. We present(More)
Noise induces generally the tuning of parameters by the user in many digital imaging applications : Output quality/accuracy depends on the choice of the parameter. Noise induces generally the tuning of parameters by the user in many digital imaging applications : Output quality/accuracy depends on the choice of the parameter.
Thirteen colonies of Dinoponera quadriceps were studied in the field in Brazil. Dissection of all workers showed that each worker has ovaries with 6 ovarioles/ovary and a functional spermatheca. Moreover, the continuity of ovarian physiological states among workers is remarkable. Egg laying is performed by mated worker ( = gamergates) but also by few(More)
Contributions Digital geometry denes geometric properties onto subsets of the digital plane (generally Z 2 or Z 3). In Z 2 , digital shapes are eciently analyzed by the maximal digital straight segments along their contours. They indeed present many desirable properties: they characterize the convexity, they dene a linear approximation of the shape and can(More)
Iso-surfaces are routinely used for the visualization of volumetric structures. Further processing (such as quantitative analysis, morphometric measurements, shape description) requires volume representations. The skeleton representation matches these requirements by providing a concise description of the object. This paper has two parts. First, we exhibit(More)
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