Traditionally, measurement of the acute toxicity of pesticides to beneficial arthropods has relied largely on the determination of an acute median lethal dose or concentration. However, the estimated lethal dose during acute toxicity tests may only be a partial measure of the deleterious effects. In addition to direct mortality induced by pesticides, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. An increasing number of studies and methods related to the identification and characterization of these effects have been published in the past 15 years. Review of sublethal effects reported in published literature, taking into account recent data, has revealed new insights into the sublethal effects of pesticides including effects on learning performance, behavior, and neurophysiology. We characterize the different types of sublethal effects on beneficial arthropods, focusing mainly on honey bees and natural enemies, and we describe the methods used in these studies. Finally, we discuss the potential for developing experimental approaches that take into account these sublethal effects in integrated pest management and the possibility of integrating their evaluation in pesticide registration procedures.

The Sublethal Effects of Pesticides on Beneficial Arthropods

For animals that forage or travel in groups, making movement decisions often depends on social interactions among group members. However, in many cases, few individuals have pertinent information, such as knowledge about the location of a food source, or of a migration route. Using a simple model we show how information can be transferred within groups both without signalling and when group members do not know which individuals, if any, have information. We reveal that the larger the group the smaller the proportion of informed individuals needed to guide the group, and that only a very small proportion of informed individuals is required to achieve great accuracy. We also demonstrate how groups can make consensus decisions, even though informed individuals do not know whether they are in a majority or minority, how the quality of their information compares with that of others, or even whether there are any other informed individuals. Our model provides new insights into the mechanisms of effective leadership and decision-making in biological systems.

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Effective leadership and decision-making in animal groups on the move

What determines the timing of human actions? A big question, but the science of human dynamics is here to tackle it. And its predictions are of practical value: for example, when ISPs decide what bandwidth an institution needs, they use a model of the likely timing and activity level of the individuals. Current models assume that an individual has a well defined probability of engaging in a specific action at a given moment, but evidence that the timing of human actions does not follow this pattern (of Poisson statistics) is emerging. Instead the delay between two consecutive events is best described by a heavy-tailed (power law) distribution. Albert-Laszlo Barabasi proposes an explanation for the prevalence of this behaviour. The ‘bursty’ nature of human dynamics, he finds, is a fundamental consequence of decision making. The dynamics of many social, technological and economic phenomena are driven by individual human actions, turning the quantitative understanding of human behaviour into a central question of modern science. Current models of human dynamics, used from risk assessment to communications, assume that human actions are randomly distributed in time and thus well approximated by Poisson processes1,2,3. In contrast, there is increasing evidence that the timing of many human activities, ranging from communication to entertainment and work patterns, follow non-Poisson statistics, characterized by bursts of rapidly occurring events separated by long periods of inactivity4,5,6,7,8. Here I show that the bursty nature of human behaviour is a consequence of a decision-based queuing process9,10: when individuals execute tasks based on some perceived priority, the timing of the tasks will be heavy tailed, with most tasks being rapidly executed, whereas a few experience very long waiting times. In contrast, random or priority blind execution is well approximated by uniform inter-event statistics. These finding have important implications, ranging from resource management to service allocation, in both communications and retail.

The origin of bursts and heavy tails in human dynamics

It is well documented that animals take risk of predation into account when making decisions about how to behave in particular situations, often trading-off risk against opportunities for mating or acquiring energy. Such an ability implies that animals have reliable information about the risk of predation at a given place and time. Chemosensory cues are an important source of such information. They reliably reveal the presence of predators (or their presence in the immediate past) and may also provide information on predator activity level and diet. In certain circumstances (e.g., in the dark, for animals in hiding) they may be the only cues available. Although a vast literature exists on the responses of prey to predator chemosensory cues (or odours), these studies are widely scattered, from marine biology to biological control, and not well known or appreciated by behavioural ecologists. In this paper, we provide an exhaustive review of this literature, primarily in tabular form. We highlight so...

The scent of death: Chemosensory assessment of predation risk by prey animals

DURING the past few decades, investigations have been made into various active substances which, though they resemble hormones in some respects, cannot be included among them. For example, the sexual attractants of butterflies are, like hormones, produced and secreted by special glands; minute amounts cause a specific reaction in the receptor organ (the antenna of the male), which eventually leads to a state of copulative readiness. Unlike hormones, however, the substance is not secreted into the blood but outside the body; it does not serve humoral correlation within the organism but communication between individuals.

‘Pheromones’: a New Term for a Class of Biologically Active Substances

Until his death in 1982, Karl von Frisch was the world's most renowned authority on bees. "The Dance Language and Orientation of Bees" is his masterwork - the culmination of more than fifty years of research. Now available for the first time in paperback, it describes in non-technical language what he discovered in a lifetime of study about honeybees - their methods of orientation, their sensory faculties, and their remarkable ability to communicate with one another. Thomas Seeley's new foreword traces the revolutionary effects of von Frisch's work, not just for the study of bees, but for all subsequent research in animal behaviour. This new paperback edition also includes a "Personal Appreciation" of von Frisch by the distinguished biologist Martin Lindauer, who was von Frisch's protege and later his colleague and friend.

The dance language and orientation of bees

Tanzsprache und Orientierung der Bienen

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Der farbensinn und Formensinn der Biene.

Over half a century of brilliant scientific detective work, the Nobel Prize-winning biologist Karl von Frisch learned how the world, looks, smells, and tastes to a bee. More significantly, he discovered their dance language and their ability to use the sun as a compass. Intended to serve as an accessible introduction to one of the most fascinating areas of biology, Bees (first published in 1950 and revised in 1971), reported the startling results of his ingenious and revolutionary experiments with honeybees.In his revisions, von Frisch updated his discussion about the phylogenetic origin of the language of bees and also demonstrated that their color sense is greater than had been thought previously. He also took into consideration the electrophysiological experiments and electromicroscopic observations that have supplied more information on how the bee analyzes polarized light to orient itself and how the olfactory organs on the bee's antennae function.Now back in print after more than two decades, this classic and still-accurate account of the behavior patterns and sensory capacities of the honeybee remains a book “written with a simplicity, directness, and charm which all who know him will recognize as characteristic of its author. Any intelligent reader, without scientific training, can enjoy it.”—Yale Review

Karl von Frisch

Papers

The dance language and orientation of bees

Tanzsprache und Orientierung der Bienen

Der farbensinn und Formensinn der Biene.

Bees: their vision, chemical senses, and language

Bees: Their Vision, Chemical Senses, and Language