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

A new role for the insect mushroom bodies: place memory and motor control

The organization and evolutionary implications of neuropils and their neurons in the brain of the onychophoran Euperipatoides rowelli.

The lobes of the mushroom bodies of the cockroach Periplaneta americana consist of longitudinal modules called laminae. These comprise repeating arrangements of Kenyon cell axons, which like their dendrites and perikarya have an affinity to one of three antisera: to taurine, aspartate, or glutamate. Taurine-immunopositive laminae alternate with immunonegative ones. Aspartate-immunopositive Kenyon cell axons are distributed across the lobes. However, smaller leaf-like ensembles of axons that reveal particularly high affinities to anti-aspartate are embedded within taurine-positive laminae and occur in the immunonegative laminae between them. Together, these arrangements reveal a complex architecture of repeating subunits whose different levels of immunoreactivity correspond to broader immunoreactive layers identified by sera against the neuromodulator FMRFamide. Throughout development and in the adult, the most posterior lamina is glutamate immunopositive. Its axons arise from the most recently born Kenyon cells that in the adult retain their juvenile character, sending a dense system of collaterals to the front of the lobes. Glutamate-positive processes intersect aspartate- and taurine-immunopositive laminae and are disposed such that they might play important roles in synaptogenesis or synapse modification. Glutamate immunoreactivity is not seen in older, mature axons, indicating that Kenyon cells show plasticity of neurotransmitter phenotype during development. Aspartate may be a universal transmitter substance throughout the lobes. High levels of taurine immunoreactivity occur in broad laminae containing the high concentrations of synaptic vesicles. J. Comp. Neurol. 439: 352‐367, 2001. © 2001 Wiley-Liss, Inc. Indexing terms: amino acid immunoreactivity; glutamate; brain parcellation; insect; learning and memory

Taurine-, aspartate- and glutamate-like immunoreactivity identifies chemically distinct subdivisions of Kenyon cells in the cockroach mushroom body.

Antisera against the neuromodulatory peptides, Phe-Met-Arg-Phe-NH(2)-amide (FMRFamide) and gastrin cholecystokinin, demonstrate that the mushroom bodies of honey bees are subdivided longitudinally into strata. Three-dimensional reconstructions demonstrate that these strata project in parallel through the entire pedunculus and through the medial and vertical lobes. Immunostaining reveals clusters of immunoreactive cell bodies within the calyx cups and immunoreactive bundles of axons that line the inside of the calyx cup and lead to strata. Together, these features reveal that immunoreactive strata are composed of Kenyon cell axons rather than extrinsic elements, as suggested previously by some authors. Sorting amongst Kenyon cell axons into their appropriate strata already begins in the calyx before these axons enter the pedunculus. The three main concentric divisions of each calyx (the lip, collar, and basal ring) are divided further into immunoreactive and immunonegative zones. The lip neuropil is divided into two discrete zones, the collar neuropil is divided into five zones, and the basal ring neuropil is divided into four zones. Earlier studies proposed that the lip, collar, and basal ring are represented by three broad bands in the lobes: axons from adjacent Kenyon cell dendrites in the calyces are adjacent in the lobes even after their polar arrangements in the calyces have been transformed to rectilinear arrangements in the lobes. The universality of this arrangement is not supported by the present results. Although immunoreactive zones are found in all three calycal regions, immunoreactive strata in the lobes occur mainly in the two bands that were ascribed previously to the collar and the basal ring. In the lobes, immunoreactive strata are visited by the dendrites of efferent neurons that carry information from the mushroom bodies to other parts of the brain. Morphologically and chemically distinct subdivisions through the pedunculus and lobes of honey bees are comparable to longitudinal subdivisions demonstrated in the mushroom bodies of other insects, such as the cockroach Periplaneta americana. The functional and evolutionary significance of the results is discussed.

Parallel organization in honey bee mushroom bodies by peptidergic Kenyon cells.

Insects share the same physical environment as terrestrial vertebrates. However, insects are vastly more successful in terms of their adaptive radiation and colonization. The biomass of insects alone is said to outweigh all other organisms and it can be speculated that their evolutionary success is a consequence, not only of their environmental colonization, but also of their behavioral versatility which sets them apart from other terrestrial arthopods. If this hypothesis is correct, it might be expected that there exist neural organizations that are peculiar to, or greatly elaborated in, the Insecta alone. This chapter describes the occurrence among selected arthropods of a brain region that, in eusocial insects, reaches great complexity and is implicated in learning and memory. Its identification in various taxa is assessed against the background of current theories of arthropod evolution and brain segmentation.

Nicholas J. Strausfeld

Papers

A new role for the insect mushroom bodies: place memory and motor control

The organization and evolutionary implications of neuropils and their neurons in the brain of the onychophoran Euperipatoides rowelli.

Taurine-, aspartate- and glutamate-like immunoreactivity identifies chemically distinct subdivisions of Kenyon cells in the cockroach mushroom body.

Parallel organization in honey bee mushroom bodies by peptidergic Kenyon cells.

The arthropod mushroom body: Its functional roles, evolutionary enigmas and mistaken identities