The Insects has been the standard textbook in the field since the first edition published over forty years ago. Building on the strengths of Chapman's original text, this long-awaited 5th edition has been revised and expanded by a team of eminent insect physiologists, bringing it fully up-to-date for the molecular era. The chapters retain the successful structure of the earlier editions, focusing on particular functional systems rather than taxonomic groups and making it easy for students to delve into topics without extensive knowledge of taxonomy. The focus is on form and function, bringing together basic anatomy and physiology and examining how these relate to behaviour. This, combined with nearly 600 clear illustrations, provides a comprehensive understanding of how insects work. Now also featuring a richly illustrated prologue by George McGavin, this is an essential text for students, researchers and applied entomologists alike.

The insects: structure and function.

Mosaic analysis with a repressible cell marker for studies of gene function in neuronal morphogenesis.

The administration of leptin to leptin-deficient humans, and the analogous Lepob/Lepob mice, effectively reduces hyperphagia and obesity. But common obesity is associated with elevated leptin, which suggests that obese humans are resistant to this adipocyte hormone. In addition to regulating long-term energy balance, leptin also rapidly affects neuronal activity. Proopiomelanocortin (POMC) and neuropeptide-Y types of neurons in the arcuate nucleus of the hypothalamus are both principal sites of leptin receptor expression and the source of potent neuropeptide modulators, melanocortins and neuropeptide Y, which exert opposing effects on feeding and metabolism. These neurons are therefore ideal for characterizing leptin action and the mechanism of leptin resistance; however, their diffuse distribution makes them difficult to study. Here we report electrophysiological recordings on POMC neurons, which we identified by targeted expression of green fluorescent protein in transgenic mice. Leptin increases the frequency of action potentials in the anorexigenic POMC neurons by two mechanisms: depolarization through a nonspecific cation channel; and reduced inhibition by local orexigenic neuropeptide-Y/GABA (gamma-aminobutyric acid) neurons. Furthermore, we show that melanocortin peptides have an autoinhibitory effect on this circuit. On the basis of our results, we propose an integrated model of leptin action and neuronal architecture in the arcuate nucleus of the hypothalamus.

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Leptin activates anorexigenic POMC neurons through a neural network in the arcuate nucleus

Recent advances in integrative studies of locomotion have revealed several general principles. Energy storage and exchange mechanisms discovered in walking and running bipeds apply to multilegged locomotion and even to flying and swimming. Nonpropulsive lateral forces can be sizable, but they may benefit stability, maneuverability, or other criteria that become apparent in natural environments. Locomotor control systems combine rapid mechanical preflexes with multimodal sensory feedback and feedforward commands. Muscles have a surprising variety of functions in locomotion, serving as motors, brakes, springs, and struts. Integrative approaches reveal not only how each component within a locomotor system operates but how they function as a collective whole.

https://science.sciencemag.org/content/sci/288/5463/100.full.pdf

How Animals Move: An Integrative View

We have developed a method for temporal and regional gene expression targeting (TARGET) in Drosophila and show the simultaneous spatial and temporal rescue of a memory defect. The transient expression of the rutabaga-encoded adenylyl cyclase in the mushroom bodies of the adult brain was necessary and sufficient to rescue the rutabaga memory deficit, which rules out a developmental brain defect in the etiology of this deficit and demonstrates an acute role for rutabaga in memory formation in these neurons. The TARGET system offers general utility in simultaneously addressing issues of when and where gene products are required.

https://science.sciencemag.org/content/sci/302/5651/1765.full.pdf

Spatiotemporal rescue of memory dysfunction in Drosophila

Studies of the mushroom bodies of Drosophila melanogaster have suggested that their gamma lobes specifically support short-term memory, whereas their vertical lobes are essential for long-term memory. Developmental studies have demonstrated that the Drosophila gamma lobe, like its equivalent in the cockroach Periplaneta americana, is supplied by a special class of intrinsic neuron-the clawed Kenyon cells-that are the first to differentiate during early development. To date, however, no account identifies a corresponding lobe in the honey bee, another taxon used extensively for learning and memory research. Received opinion is that, in this taxon, each of the mushroom body lobes comprises three parallel divisions representing one of three concentric zones of the calyces, called the lip, collar, and basal ring. The present account shows that, although these zones are represented in the lobes, they occupy only two thirds of the vertical lobe. Its lowermost third receives the axons of the clawed class II Kenyon cells, which are the first to differentiate during early development and which represent the whole calyx. This component of the lobe is anatomically and developmentally equivalent to the gamma lobe of Drosophila and has been here named the gamma lobe of the honey bee. A new class of intrinsic neurons, originating from perikarya distant from the mushroom body, provides a second system of parallel fibers from the calyx to the gamma lobe. A region immediately beneath the calyces, called the neck, is invaded by these neurons as well as by a third class of intrinsic cell that provides connections within the neck of the pedunculus and the basal ring of the calyces. In the honey bee, the gamma lobe is extensively supplied by afferents from the protocerebrum and gives rise to a distinctive class of efferent neurons. The terminals of these efferents target protocerebral neuropils that are distinct from those receiving efferents from divisions of the vertical lobe that represent the lip, collar, and basal ring. The identification of a gamma lobe unites the mushroom bodies of evolutionarily divergent taxa. The present findings suggest the need for critical reinterpretation of studies that have been predicated on early descriptions of the mushroom body's lobes.

Organization of the honey bee mushroom body: representation of the calyx within the vertical and gamma lobes.

The arthropod central complex and vertebrate basal ganglia derive from embryonic basal forebrain lineages that are specified by an evolutionarily conserved genetic program leading to interconnected neuropils and nuclei that populate the midline of the forebrain-midbrain boundary region. In the substructures of both the central complex and basal ganglia, network connectivity and neuronal activity mediate control mechanisms in which inhibitory (GABAergic) and modulatory (dopaminergic) circuits facilitate the regulation and release of adaptive behaviors. Both basal ganglia and central complex dysfunction result in behavioral defects including motor abnormalities, impaired memory formation, attention deficits, affective disorders, and sleep disturbances. The observed multitude of similarities suggests deep homology of arthropod central complex and vertebrate basal ganglia circuitries underlying the selection and maintenance of behavioral actions.

https://science.sciencemag.org/content/sci/340/6129/157.full.pdf

Deep Homology of Arthropod Central Complex and Vertebrate Basal Ganglia

Dissection of the peripheral motion channel in the visual system of Drosophila melanogaster.

Insects and other arthropods use visual landmarks to remember the location of their nest, or its equivalent. However, so far, only olfactory learning and memory have been claimed to be mediated by any particular brain region, notably the mushroom bodies. Here we describe the results of experiments that demonstrate that the mushroom bodies of the cockroach (Periplaneta americana), already shown to be involved in multimodal sensory processing, play a crucial role in place memory. Behavioral tests, based on paradigms similar to those originally used to demonstrate place memory in rats, demonstrate a rapid improvement in the ability of individual cockroaches to locate a hidden target when its position is provided by distant visual cues. Bilateral lesions of selected areas of the mushroom bodies abolish this ability but leave unimpaired the ability to locate a visible target. The present results demonstrate that the integrity of the pedunculus and medial lobe of a single mushroom body is required for place memory. The results are comparable to the results obtained from hippocampal lesions in rats and are relevant to recent studies on the effects of ablations of Drosophila mushroom bodies on locomotion. J. Comp. Neurol. 402:520–537, 1998. © 1998 Wiley-Liss, Inc.

Mushroom bodies of the cockroach: their participation in place memory.

In The Descent of Man, Charles Darwin proposed that an ant's brain, no larger than a pin's head, must be sophisticated to accomplish all that it does. Yet today many people still find it surprising that insects and other arthropods show behaviors that are much more complex than innate reflexes. They are products of versatile brains which, in a sense, think. Fascinating in their own right, arthropods provide fundamental insights into how brains process and organize sensory information to produce learning, strategizing, cooperation, and sociality. Nicholas Strausfeld elucidates the evolution of this knowledge, beginning with nineteenth-century debates about how similar arthropod brains were to vertebrate brains. This exchange, he shows, had a profound and far-reaching impact on attitudes toward evolution and animal origins. Many renowned scientists, including Sigmund Freud, cut their professional teeth studying arthropod nervous systems. The greatest neuroanatomist of them all, Santiago Ramon y Cajal--founder of the neuron doctrine--was awed by similarities between insect and mammalian brains. Writing in a style that will appeal to a broad readership, Strausfeld weaves anatomical observations with evidence from molecular biology, neuroethology, cladistics, and the fossil record to explore the neurobiology of the largest phylum on earth--and one that is crucial to the well-being of our planet. Highly informative and richly illustrated, Arthropod Brains offers an original synthesis drawing on many fields, and a comprehensive reference that will serve biologists for years to come.

Nicholas J. Strausfeld

Papers

Organization of the honey bee mushroom body: representation of the calyx within the vertical and gamma lobes.

Deep Homology of Arthropod Central Complex and Vertebrate Basal Ganglia

Dissection of the peripheral motion channel in the visual system of Drosophila melanogaster.

Mushroom bodies of the cockroach: their participation in place memory.

Arthropod Brains: Evolution, Functional Elegance, and Historical Significance