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Annual Review of Entomology - Volume 58, 2013
Volume 58, 2013
- Preface
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Life as a Cataglyphologist—and Beyond
Vol. 58 (2013), pp. 1–18More LessRüdiger Wehner's lifelong research activities centered on Cataglyphis have rendered these thermophilic desert ants model organisms in the study of animal navigation. The present account describes how the author encountered Cataglyphis and established a study site at Maharès, Tunisia; how he increasingly focused his research on the neuroethological analysis of the ant's navigational toolkit; and finally, how he extended these studies to thermophilic desert ants in other deserts of the world, to Ocymyrmex in southern Africa and Melophorus in central Australia. By including aspects of functional morphology, physiology, and ecology in his research projects, he has favored—and advocated—an organism-centered approach. Beyond “cataglyphology,” he was engaged in substantial teaching both at his home university in Zürich and overseas, writing a textbook, running a department, and working as a Permanent Fellow at the Institute for Advanced Study in Berlin.
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Ecological Mechanisms Underlying Arthropod Species Diversity in Grasslands
Vol. 58 (2013), pp. 19–36More LessArthropods are an important component of grassland systems, contributing significantly to biodiversity and ecosystem structure and function. Climate, fire, and grazing by large herbivores are important drivers in grasslands worldwide. Arthropod responses to these drivers are highly variable and clear patterns are difficult to find, but responses are largely indirect with respect to changes in resources, species interactions, habitat structure, and habitat heterogeneity resulting from interactions among fire, grazing, and climate. Here, we review these ecological mechanisms influencing grassland arthropod diversity. We summarize hypotheses describing species diversity at local and regional scales and then discuss specific factors that may affect arthropod diversity in grassland systems. These factors include direct and indirect effects of grazing, fire, and climate, species interactions, above- and belowground interactions, and landscape-level effects.
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Recurrent Evolution of Dependent Colony Foundation Across Eusocial Insects
Vol. 58 (2013), pp. 37–55More LessThe spectacular success of eusocial insects can be attributed to their sophisticated cooperation, yet cooperation is conspicuously absent during colony foundation when queens are alone. Selection against this solitary stage has led to a dramatically different strategy in thousands of eusocial insect species in which colonies are started by groups of nestmates and the benefits of sociality are retained continuously. Dependent colony foundation (DCF) evolved recurrently multiple times across the ants, bees, and wasps, though its prevalence in termites remains unclear. We review adaptations at both the colony level (reproductive investment shifts from sexuals to workers) and the individual level (wingless queens evolve in ants), and other consequences for life history (invasiveness, parasite transmission). Although few studies have focused on DCF, the accumulated data from anecdotal reports, supported by indirect information including morphology, population genetics, and colony demographics, make it clear that this strategy is more diverse and widespread than is usually recognized.
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The Impact of Molecular Data on Our Understanding of Bee Phylogeny and Evolution
Vol. 58 (2013), pp. 57–78More LessOur understanding of bee phylogeny has improved over the past fifteen years as a result of new data, primarily nucleotide sequence data, and new methods, primarily model-based methods of phylogeny reconstruction. Phylogenetic studies based on single or, more commonly, multilocus data sets have helped resolve the placement of bees within the superfamily Apoidea; the relationships among the seven families of bees; and the relationships among bee subfamilies, tribes, genera, and species. In addition, molecular phylogenies have played an important role in inferring evolutionary patterns and processes in bees. Phylogenies have provided the comparative framework for understanding the evolution of host-plant associations and pollen specialization, the evolution of social behavior, and the evolution of parasitism. In this paper, we present an overview of significant discoveries in bee phylogeny based primarily on the application of molecular data. We review the phylogenetic hypotheses family-by-family and then describe how the new phylogenetic insights have altered our understanding of bee biology.
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An Emerging Understanding of Mechanisms Governing Insect Herbivory Under Elevated CO2
Vol. 58 (2013), pp. 79–97More LessBy changing the chemical composition of foliage, the increase in atmospheric CO2 is fundamentally altering insect herbivory. The responses of folivorous insects to these changes is, however, highly variable. In this review we highlight emerging mechanisms by which increasing CO2 alters the defense chemistry and signaling of plants. The response of allelochemicals affecting insect performance varies under elevated CO2, and results suggest this is driven by changes in plant hormones. Increasing CO2 suppresses the production of jasmonates and ethylene and increases the production of salicylic acid, and these differential responses of plant hormones affect specific secondary chemical pathways. In addition to changes in secondary chemistry, elevated CO2 decreases rates of water loss from leaves, increases temperature and feeding rates, and alters nutritional content. New insights into the mechanistic responses of secondary chemistry to elevated CO2 increase our ability to predict the ecological and evolutionary responses of plants attacked by insects.
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Neuroactive Insecticides: Targets, Selectivity, Resistance, and Secondary Effects
Vol. 58 (2013), pp. 99–117More LessNeuroactive insecticides are the principal means of protecting crops, people, livestock, and pets from pest insect attack and disease transmission. Currently, the four major nerve targets are acetylcholinesterase for organophosphates and methylcarbamates, the nicotinic acetylcholine receptor for neonicotinoids, the γ-aminobutyric acid receptor/chloride channel for polychlorocyclohexanes and fiproles, and the voltage-gated sodium channel for pyrethroids and dichlorodiphenyltrichloroethane. Species selectivity and acquired resistance are attributable in part to structural differences in binding subsites, receptor subunit interfaces, or transmembrane regions. Additional targets are sites in the sodium channel (indoxacarb and metaflumizone), the glutamate-gated chloride channel (avermectins), the octopamine receptor (amitraz metabolite), and the calcium-activated calcium channel (diamides). Secondary toxic effects in mammals from off-target serine hydrolase inhibition include organophosphate-induced delayed neuropathy and disruption of the cannabinoid system. Possible associations between pesticides and Parkinson's and Alzheimer's diseases are proposed but not established based on epidemiological observations and mechanistic considerations.
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Biological Pest Control in Mexico
Vol. 58 (2013), pp. 119–140More LessMexico is a megadiverse country that forms part of the Mesoamerican biological corridor that connects North and South America. Mexico's biogeographical situation places it at risk from invasive exotic insect pests that enter from the United States, Central America, or the Caribbean. In this review we analyze the factors that contributed to some highly successful past programs involving classical biological control and/or the sterile insect technique (SIT). The present situation is then examined with reference to biological control, including SIT programs, targeted at seven major pests, with varying degrees of success. Finally, we analyze the current threats facing Mexico's agriculture industry from invasive pests that have recently entered the country or are about to do so. We conclude that despite a number of shortcomings, Mexico is better set to develop biological control–based pest control programs, particularly on an area-wide basis, than many other Latin American countries are. Classical and augmentative biological control and SIT-based programs are likely to provide effective and sustainable options for control of native and exotic pests, particularly when integrated into technology packages that meet farmers' needs across the great diversity of production systems in Mexico.
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Nutritional Ecology of Entomophagy in Humans and Other Primates
Vol. 58 (2013), pp. 141–160More LessEntomophagy is widespread among nonhuman primates and is common among many human communities. However, the extent and patterns of entomophagy vary substantially both in humans and nonhuman primates. Here we synthesize the literature to examine why humans and other primates eat insects and what accounts for the variation in the extent to which they do so. Variation in the availability of insects is clearly important, but less understood is the role of nutrients in entomophagy. We apply a multidimensional analytical approach, the right-angled mixture triangle, to published data on the macronutrient compositions of insects to address this. Results showed that insects eaten by humans spanned a wide range of protein-to-fat ratios but were generally nutrient dense, whereas insects with high protein-to-fat ratios were eaten by nonhuman primates. Although suggestive, our survey exposes a need for additional, standardized, data.
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Conservation and Variation in Hox Genes: How Insect Models Pioneered the Evo-Devo Field
Alison Heffer, and Leslie PickVol. 58 (2013), pp. 161–179More LessEvolutionary developmental biology, or evo-devo, broadly investigates how body plan diversity and morphological novelties have arisen and persisted in nature. The discovery of Hox genes in Drosophila, and their subsequent identification in most other metazoans, led biologists to try to understand how embryonic genes crucial for proper development have changed to promote the vast morphological variation seen in nature. Insects are ideal model systems for studying this diversity and the mechanisms underlying it because phylogenetic relationships are well established, powerful genetic tools have been developed, and there are many examples of evolutionary specializations that have arisen in nature in different insect lineages, such as the jumping leg of orthopterans and the helmet structures of treehoppers. Here, we briefly introduce the field of evo-devo and Hox genes, discuss functional tools available to study early developmental genes in insects, and provide examples in which changes in Hox genes have contributed to changes in body plan or morphology.
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The Juvenile Hormone Signaling Pathway in Insect Development
Vol. 58 (2013), pp. 181–204More LessThe molecular action of juvenile hormone (JH), a regulator of vital importance to insects, was until recently regarded as a mystery. The past few years have seen an explosion of studies of JH signaling, sparked by a finding that a JH-resistance gene, Methoprene-tolerant (Met), plays a critical role in insect metamorphosis. Here, we summarize the recently acquired knowledge on the capacity of Met to bind JH, which has been mapped to a particular ligand-binding domain, thus establishing this bHLH-PAS protein as a novel type of an intracellular hormone receptor. Next, we consider the significance of JH-dependent interactions of Met with other transcription factors and signaling pathways. We examine the regulation and biological roles of genes acting downstream of JH and Met in insect metamorphosis. Finally, we discuss the current gaps in our understanding of JH action and outline directions for future research.
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The Adult Dipteran Crop: A Unique and Overlooked Organ
Vol. 58 (2013), pp. 205–225More LessThe diverticulated crop is a unique and overlooked foregut organ in the Diptera that affects many physiological and behavioral functions. Historically, the crop was viewed simply as a reservoir for excess nutrients. The crop lobes and crop duct form an elaborate sphincter and pump system that moves stored nutrients to the crop lobes, oral cavity, and the midgut. The storage capacity of the crop lobes is significant when filled maximally and supplies sufficient carbohydrates to sustain prolonged activity and flight, and adequate protein and lipids to facilitate reproductive events. Crop emptying is under complex neuroendocrine and neural control and may be influenced by multiple neuromessengers, such as serotonin and dromyosuppressin. The crop lobes also serve as a site for the initial mixing of enzymes from the salivary glands and antimicrobials from the labellar glands with ingested food. These food-processing functions are associated with behaviors unique to dipterans, such as regurgitation (or bubbling), nuptial gift giving, and substrate droplet deposition or trap-lining.
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Biology of Phlebotomine Sand Flies as Vectors of Disease Agents
Vol. 58 (2013), pp. 227–250More LessPhlebotomines are the sole or principal vectors of Leishmania, Bartonella bacilliformis, and some arboviruses. The coevolution of sand flies with Leishmania species of mammals and lizards is considered in relation to the landscape epidemiology of leishmaniasis, a neglected tropical disease. Evolutionary hypotheses are unresolved, so a practical phlebotomine classification is proposed to aid biomedical information retrieval. The vectors of Leishmania are tabulated and new criteria for their incrimination are given. Research on fly-parasite-host interactions, fly saliva, and behavioral ecology is reviewed in relation to parasite manipulation of blood feeding, vaccine targets, and pheromones for lures. Much basic research is based on few transmission cycles, so generalizations should be made with caution. Integrated research and control programs have begun, but improved control of leishmaniasis and nuisance-biting requires greater emphasis on population genetics and transmission modeling. Most leishmaniasis transmission is zoonotic, affecting the poor and tourists in rural and natural areas, and therefore control should be compatible with environmental conservation.
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Ecdysone Receptors: From the Ashburner Model to Structural Biology*
Vol. 58 (2013), pp. 251–271More LessIn 1974, Ashburner and colleagues postulated a model to explain the control of the puffing sequence on Drosophila polytene chromosomes initiated by the molting hormone 20-hydroxyecdysone. This model inspired a generation of molecular biologists to clone and characterize elements of the model, thereby providing insights into the control of gene networks by steroids, diatomic gases, and other small molecules. It led to the first cloning of the EcR subunit of the heterodimeric EcR-USP ecdysone receptor. X-ray diffraction studies of the ligand-binding domain of the receptor are elucidating the specificity of receptor-ecdysteroid interactions, the selectivity of some environmentally friendly insecticides, the evolution of the EcR-USP heterodimer, and indeed Ashburner's classical biochemical evidence for the central role of the ecdysone receptor in his model.
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Thelytokous Parthenogenesis in Eusocial Hymenoptera
Vol. 58 (2013), pp. 273–292More LessFemale parthenogenesis, or thelytoky, is particularly common in solitary Hymenoptera. Only more recently has it become clear that many eusocial species also regularly reproduce thelytokously, and here we provide a comprehensive overview. Especially in ants, thelytoky underlies a variety of idiosyncratic life histories with unique evolutionary and ecological consequences. In all eusocial species studied, thelytoky probably has a nuclear genetic basis and the underlying cytological mechanism retains high levels of heterozygosity. This is in striking contrast to many solitary wasps, in which thelytoky is often induced by cytoplasmic bacteria and results in an immediate loss of heterozygosity. These differences are likely related to differences in haplodiploid sex determination mechanisms, which in eusocial species usually require heterozygosity for female development. At the same time, haplodiploidy might account for important preadaptations that can help explain the apparent ease with which Hymenoptera transition between sexual and asexual reproduction.
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Red Turpentine Beetle: Innocuous Native Becomes Invasive Tree Killer in China
Vol. 58 (2013), pp. 293–311More LessThe red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is a secondary pest of pines in its native range in North and Central America. Outbreaks and tree mortality attributed to RTB alone are rare in its native range. RTB was introduced into China in the early 1980s and spread rapidly from Shanxi Province to four adjacent provinces; it has infested over 500,000 ha of pine forest and has caused extensive tree mortality since 1999. We provide a historical background on RTB outbreaks, explanations for its invasive success, management options, and economic impacts of RTB in China. Genetic variation in RTB fungal associates, interactions between RTB and its associated fungi, behavioral differences in Chinese RTB, and other factors favoring RTB outbreaks are considered in an effort to explain the invasiveness of RTB in China. The promise of semiochemicals as a management tool is also discussed.
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Vision in Drosophila: Seeing the World Through a Model's Eyes
Vol. 58 (2013), pp. 313–332More LessThe fruit fly, Drosophila melanogaster, has been used for decades as a genetic model for unraveling mechanisms of development and behavior. In order to efficiently assign gene functions to cellular and behavioral processes, early measures were often necessarily simple. Much of what is known of developmental pathways was based on disrupting highly regular structures, such as patterns of cells in the eye. Similarly, reliable visual behaviors such as phototaxis and motion responses provided a solid foundation for dissecting vision. Researchers have recently begun to examine how this model organism responds to more complex or naturalistic stimuli by designing novel paradigms that more closely mimic visual behavior in the wild. Alongside these advances, the development of brain-recording strategies allied with novel genetic tools has brought about a new era of Drosophila vision research where neuronal activity can be related to behavior in the natural world.
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Intrinsic Inter- and Intraspecific Competition in Parasitoid Wasps
Vol. 58 (2013), pp. 333–351More LessImmature development of parasitoid wasps is restricted to resources found in a single host that is often similar in size to the adult parasitoid. When two or more parasitoids of the same or different species attack the same host, there is competition for monopolization of host resources. The success of intrinsic competition differs between parasitoids attacking growing hosts and parasitoids attacking paralyzed hosts. Furthermore, the evolution of gregarious development in parasitoids reflects differences in various developmental and behavioral traits, as these influence antagonistic encounters among immature parasitoids. Fitness-related costs (or benefits) of competition for the winning parasitoid reveal that time lags between successive attacks influence the outcome of competition. Physiological mechanisms used to exclude competitors include physical and biochemical factors that originate with the ovipositing female wasp or her progeny. In a broader multitrophic framework, indirect factors, such as plant quality, may affect parasitoids through effects on immunity and nutrition.
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Biology and Management of Palm Dynastid Beetles: Recent Advances
Vol. 58 (2013), pp. 353–372More LessCoconut, oil, and date palms are important crops in the tropics and are attacked by dynastids that cause loss of production or death of hosts. Knowledge of their breeding sites has been extended since a previous review in 1980. The fungus Metarhizium anisopliae has potential as a biopesticide against immature stages in friable breeding sites. The molecular biology and ultrastructure of Oryctes rhinoceros Nudivirus (OrNV), disseminated by adults, have been studied, and this pathogen can reduce O. rhinoceros populations and damage when introduced into new locations, especially where damage had been high. New PCR techniques may enable reliable quantification of dosages ingested and hence virulence of different isolates. Male-produced aggregation pheromones have been identified in several species, for which they may have management potential, having been used commercially for trapping O. rhinoceros in oil palm plantations in Southeast Asia, and tested against O. monoceros in Africa.
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Odorant Reception in Insects: Roles of Receptors, Binding Proteins, and Degrading Enzymes
Vol. 58 (2013), pp. 373–391More LessOur knowledge of the molecular basis of odorant reception in insects has grown exponentially over the past decade. Odorant receptors (ORs) from moths, fruit flies, mosquitoes, and the honey bees have been deorphanized, odorant-degrading enzymes (ODEs) have been isolated, and the functions of odorant-binding proteins (OBPs) have been unveiled. OBPs contribute to the sensitivity of the olfactory system by transporting odorants through the sensillar lymph, but there are competing hypotheses on how they act at the end of the journey. A few ODEs that have been demonstrated to degrade odorants rapidly may act in signal inactivation alone or in combination with other molecular traps. Although ORs in Drosophila melanogaster respond to multiple odorants and seem to work in combinatorial code involving both periphery and antennal lobes, reception of sex pheromones by moth ORs suggests that their labeled lines rely heavily on selectivity at the periphery.
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Molecular Systematics and Insecticide Resistance in the Major African Malaria Vector Anopheles funestus
Vol. 58 (2013), pp. 393–412More LessAnopheles funestus is one of three major African vectors of malaria. Its distribution extends over much of the tropics and subtropics wherever suitable swampy breeding habitats are present. As with members of the Anopheles gambiae complex, An. funestus shows marked genetic heterogeneity across its range. Currently, two unnamed species are recognized in the group, with molecular and cytogenetic data indicating that more may be present. The control of malaria vectors in Africa has received increased attention in the past decade with the scaling up of insecticide-treated bed nets and indoor residual house spraying. Also in the past decade, the frequency of insecticide-resistant mosquitoes has increased exponentially. Whether this increase is in response to vector control initiatives or because of insecticide use in agriculture is debatable. In this article we examine the progress made on the systematics of the An. funestus group and review research on insecticide resistance and its mechanisms.
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Biology and Management of Asian Citrus Psyllid, Vector of the Huanglongbing Pathogens
Vol. 58 (2013), pp. 413–432More LessThe Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the most important pest of citrus worldwide because it serves as a vector of “Candidatus Liberibacter” species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease). All commercially cultivated citrus is susceptible and varieties tolerant to disease expression are not yet available. Onset of disease occurs following a long latent period after inoculation, and thus the pathogen can spread widely prior to detection. Detection of the pathogen in Brazil in 2004 and Florida in 2005 catalyzed a significant increase in research on D. citri biology. Chemical control is the primary management strategy currently employed, but recently documented decreases in susceptibility of D. citri to several insecticides illustrate the need for more sustainable tools. Herein, we discuss recent advances in the understanding of D. citri biology and behavior, pathogen transmission biology, biological control, and chemical control with respect to “Candidatus Liberibacter asiaticus.” Our goal is to point toward integrated and biologically relevant management of this pathosystem.
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Host Preferences of Blood-Feeding Mosquitoes
Vol. 58 (2013), pp. 433–453More LessMosquitoes use plant sugars and vertebrate blood as nutritional resources. When searching for blood hosts, some mosquitoes express preferential behavior for selected species. Here, we review the available knowledge on host preference, as this is expected to affect the life history and transmission of infectious pathogens. Host preference is affected by myriad extrinsic and intrinsic factors. Inherent factors are determined by genetic selection, which appears to be controlled by adaptive advantages that result from feeding on certain host species. Host preference of mosquitoes, although having a genetic basis, is characterized by high plasticity mediated by the density of host species, which by their abundance form a readily accessible source of blood. Host-selection behavior in mosquitoes is an exception rather than the rule. Those species that express strong and inherent host-selection behavior belong to the most important vectors of infectious diseases, which suggests that this behavioral trait may have evolved in parallel with parasite-host evolution.
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Biology of Invasive Termites: A Worldwide Review
Vol. 58 (2013), pp. 455–474More LessThe number of recognized invasive termite species has increased from 17 in 1969 to 28 today. Fourteen species have been added to the list in the past 44 years; 10 have larger distributions and 4 have no reported change in distribution, and 3 species are no longer considered invasive. Although most research has focused on invasive termites in urban areas, molecular identification methods have answered questions about certain species and found that at least six species have invaded natural forest habitats. All invasive species share three characteristics that together increase the probability of creating viable propagules: they eat wood, nest in food, and easily generate secondary reproductives. These characteristics are most common in two families, the Kalotermitidae and Rhinotermitidae (which make up 21 species on the invasive termite list), particularly in three genera, Cryptotermes, Heterotermes, and Coptotermes (which together make up 16 species). Although it is the largest termite family, the Termitidae (comprising 70% of all termite species) have only two invasive species, because relatively few species have these characteristics. Islands have double the number of invasive species that continents do, with islands in the South Pacific the most invaded geographical region. Most invasive species originate from Southeast Asia. The standard control methods normally used against native pest termites are also employed against invasive termites; only two eradication attempts, in South Africa and New Zealand, appear to have been successful, both against Coptotermes species.
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Spider-Venom Peptides: Structure, Pharmacology, and Potential for Control of Insect Pests
Vol. 58 (2013), pp. 475–496More LessSpider venoms are an incredibly rich source of disulfide-rich insecticidal peptides that have been tuned over millions of years to target a wide range of receptors and ion channels in the insect nervous system. These peptides can act individually, or as part of larger toxin cabals, to rapidly immobilize envenomated prey owing to their debilitating effects on nervous system function. Most of these peptides contain a unique arrangement of disulfide bonds that provides them with extreme resistance to proteases. As a result, these peptides are highly stable in the insect gut and hemolymph and many of them are orally active. Thus, spider-venom peptides can be used as stand-alone bioinsecticides, or transgenes encoding these peptides can be used to engineer insect-resistant crops or enhanced entomopathogens. We critically review the potential of spider-venom peptides to control insect pests and highlight their advantages and disadvantages compared with conventional chemical insecticides.
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Ecdysone Control of Developmental Transitions: Lessons from Drosophila Research
Vol. 58 (2013), pp. 497–516More LessThe steroid hormone ecdysone is the central regulator of insect developmental transitions. Recent new advances in our understanding of ecdysone action have relied heavily on the application of Drosophila melanogaster molecular genetic tools to study insect metamorphosis. In this review, we focus on three major aspects of Drosophila ecdysone biology: (a) factors that regulate the timing of ecdysone release, (b) molecular basis of stage- and tissue-specific responses to ecdysone, and (c) feedback regulation and coordination of ecdysone signaling.
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Diamondback Moth Ecology and Management: Problems, Progress, and Prospects
Vol. 58 (2013), pp. 517–541More LessAgricultural intensification and greater production of Brassica vegetable and oilseed crops over the past two decades have increased the pest status of the diamondback moth (DBM), Plutella xylostella L., and it is now estimated to cost the world economy US$4–5 billion annually. Our understanding of some fundamental aspects of DBM biology and ecology, particularly host plant relationships, tritrophic interactions, and migration, has improved considerably but knowledge of other aspects, e.g., its global distribution and relative abundance, remains surprisingly limited. Biological control still focuses almost exclusively on a few species of hymenopteran parasitoids. Although these can be remarkably effective, insecticides continue to form the basis of management; their inappropriate use disrupts parasitoids and has resulted in field resistance to all available products. Improved ecological understanding and the availability of a series of highly effective selective insecticides throughout the 1990s provided the basis for sustainable and economically viable integrated pest management (IPM) approaches. However, repeated reversion to scheduled insecticide applications has resulted in resistance to these and more recently introduced compounds and the breakdown of IPM programs. Proven technologies for the sustainable management of DBM currently exist, but overcoming the barriers to their sustained adoption remains an enormous challenge.
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Neural Mechanisms of Reward in Insects
Vol. 58 (2013), pp. 543–562More LessReward seeking is a major motivator and organizer of behavior, and animals readily learn to modify their behavior to more easily obtain reward, or to respond to stimuli that are predictive of reward. Here, we compare what is known of reward processing mechanisms in insects with the well-studied vertebrate reward systems. In insects almost all of what is known of reward processing is derived from studies of reward learning. This is localized to the mushroom bodies and antennal lobes and organized by a network of hierarchically arranged modulatory circuits, especially those involving octopamine and dopamine. Neurogenetic studies with Drosophila have identified distinct circuit elements for reward learning, “wanting,” and possibly “liking” in Drosophila, suggesting a modular structure to the insect reward processing system, which broadly parallels that of the mammals in terms of functional organization.
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Potential of Insects as Food and Feed in Assuring Food Security
Vol. 58 (2013), pp. 563–583More LessWith a growing world population and increasingly demanding consumers, the production of sufficient protein from livestock, poultry, and fish represents a serious challenge for the future. Approximately 1,900 insect species are eaten worldwide, mainly in developing countries. They constitute quality food and feed, have high feed conversion ratios, and emit low levels of greenhouse gases. Some insect species can be grown on organic side streams, reducing environmental contamination and transforming waste into high-protein feed that can replace increasingly more expensive compound feed ingredients, such as fish meal. This requires the development of cost-effective, automated mass-rearing facilities that provide a reliable, stable, and safe product. In the tropics, sustainable harvesting needs to be assured and rearing practices promoted, and in general, the food resource needs to be revalorized. In the Western world, consumer acceptability will relate to pricing, perceived environmental benefits, and the development of tasty insect-derived protein products.
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A History of Entomological Classification
Vol. 58 (2013), pp. 585–607More LessThe classification of insects has attempted to most effectively communicate information about this hyperdiverse lineage of life and, not surprisingly, has had a considerably rich historical development. This history can be coarsely segregated into four periods: the Pre-Linnean era, the first century spanning Linnaeus's Systema Naturae to Darwin's On the Origin of Species, the Darwinian era up to the Cladistic Revolution, and the Hennigian era leading to today. The major events of each of these episodes are briefly summarized and some of the more notable researchers highlighted, along with their influence on our current understanding of insect relationships and how this is reflected in the current classification of the Hexapoda.
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Ants and the Fossil Record
Vol. 58 (2013), pp. 609–630More LessThe dominance of ants in the terrestrial biosphere has few equals among animals today, but this was not always the case. The oldest ants appear in the fossil record 100 million years ago, but given the scarcity of their fossils, it is presumed they were relatively minor components of Mesozoic insect life. The ant fossil record consists of two primary types of fossils, each with inherent biases: as imprints in rock and as inclusions in fossilized resins (amber). New imaging technology allows ancient ant fossils to be examined in ways never before possible. This is particularly helpful because it can be difficult to distinguish true ants from non-ants in Mesozoic fossils. Fossil discoveries continue to inform our understanding of ancient ant morphological diversity, as well as provide insights into their paleobiology.
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Previous Volumes
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Volume 69 (2024)
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Volume 68 (2023)
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Volume 67 (2022)
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Volume 66 (2021)
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Volume 65 (2020)
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Volume 64 (2019)
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Volume 63 (2018)
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Volume 62 (2017)
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Volume 61 (2016)
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Volume 60 (2015)
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Volume 59 (2014)
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Volume 58 (2013)
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Volume 57 (2012)
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Volume 56 (2011)
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Volume 55 (2010)
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Volume 54 (2009)
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Volume 53 (2008)
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Volume 52 (2007)
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Volume 51 (2006)
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Volume 50 (2005)
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Volume 49 (2004)
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Volume 48 (2003)
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Volume 47 (2002)
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Volume 46 (2001)
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Volume 45 (2000)
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Volume 44 (1999)
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Volume 43 (1998)
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Volume 42 (1997)
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Volume 41 (1996)
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Volume 40 (1995)
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Volume 39 (1994)
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Volume 38 (1993)
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Volume 37 (1992)
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Volume 36 (1991)
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Volume 35 (1990)
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Volume 34 (1989)
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Volume 33 (1988)
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Volume 32 (1987)
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Volume 31 (1986)
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Volume 30 (1985)
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Volume 29 (1984)
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Volume 28 (1983)
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Volume 27 (1982)
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Volume 26 (1981)
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Volume 25 (1980)
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Volume 24 (1979)
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Volume 23 (1978)
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Volume 22 (1977)
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Volume 21 (1976)
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Volume 20 (1975)
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Volume 19 (1974)
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Volume 18 (1973)
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Volume 17 (1972)
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Volume 16 (1971)
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Volume 15 (1970)
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Volume 14 (1969)
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Volume 13 (1968)
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Volume 12 (1967)
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Volume 11 (1966)
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Volume 10 (1965)
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Volume 9 (1964)
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Volume 8 (1963)
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Volume 7 (1962)
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Volume 6 (1961)
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Volume 5 (1960)
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Volume 4 (1959)
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Volume 3 (1958)
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Volume 2 (1957)
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Volume 1 (1956)
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Volume 0 (1932)