Perception Of Insects Research Articles

Percepção dos insetos pelos graduandos da Universidade Estadual de Feira de Santana, Bahia, Brasil

Study developed on the perception of insects by 533 undergraduates from 20 courses of the Universidade Estadual de Feira de Santana, Bahia, Brazil, has shown that, in general, the term “insect” is assigned to not systematically related organisms. Data were obtained through a simple questionnaire from October to December 1999. The construction of the “insect” ethnocategory has been determined according to ambiguous perceptions, since students have shown reactions of fear, disgust, and disdain toward those organisms included in the “insect” ethnozoological domain, and have attributed ecological, esthetical, and utilitary roles to them. The emotional meaning associated with this dominion may contribute to the understanding of both individual perception and cognitive information process

The antennal sensilla of the adult of Libellula depressa (Odonata: Libellulidae)

An ultrastructural investigation (SEM, TEM) on the antennal flagellum of the adult of the dragonfly Libellula depressa (Odonata:Libellulidae) revealed sensilla located in pits on the lateral–ventral side of the antenna. These sensilla are represented by sensilla coeloconica and by deeply sunken sensilla. The sensilla coeloconica are innervated by three unbranched dendrites, which enter the peg and show a dendrite sheath ending at the base of the peg. The peg has no socket and its cuticle is irregular with wide pore-like structures at the base of which actual pores are visible. The structure of these coeloconic sensilla is in agreement with that reported for single-walled insect chemoreceptors. The deeply sunken sensilla are represented by two kinds of sensilla styloconica, named type-1 and type-2, located at the bottom of deep cavities appearing as simple openings on the antennal surface. These sensilla are no-pore sensilla with inflexible socket and unbranched dendrites and, notwithstanding their structural differences, share common features typical of thermo/hygroreceptors. The presence of chemoreceptors in adult dragonflies sheds light on evolutionary trends in insect perception; the previously unknown occurrence of thermo/hygroreceptors in dragonflies is very important in view of the reported ability of Odonata to thermoregulate heliothermically.

UVB-Based Mate-Choice Cues Used by Females of the Jumping Spider Phintella vittata

Although there are numerous examples of animals having photoreceptors sensitive to UVA (315-400 nm) [1] and relying on UVA-based mate-choice cues [2-5], here we provide the first evidence of an animal using UVB (280-315 nm) for intraspecific communication. An earlier study showed that Phintella vittata, a jumping spider (Salticidae) from China, reflects UVB [6]. By performing six series of binary mate-choice experiments in which we varied lighting conditions with filters (UVB+ [no filter] versus UVB-, UVB+ versus ND1, UVB+ versus ND2, UVB- versus ND1, UVB- versus ND2, and UVB- versus UVA-), we show that significantly more UVB + males than UVB- males are chosen by females as preferred mates. Female preference for UVB-reflective males is not affected by differences in brightness or by UVA.

Molecular and cellular organization of insect chemosensory neurons

Animals use their chemosensory systems to detect and discriminate among chemical cues in the environment. Remarkable progress has recently been made in our knowledge of the molecular and cellular basis of chemosensory perception in insects, based largely on studies in Drosophila. This progress has been possible due to the identification of gene families for olfactory and gustatory receptors, the use of electro-physiological recording techniques on sensory neurons, the multitude of genetic manipulations that are available in this species, and insights from several insect model systems. Recent studies show that the superfamily of chemoreceptor proteins represent the essential elements in chemosensory coding, endowing chemosensory neurons with their abilities to respond to specific sets of odorants, tastants or pheromones. Investigating how insects detect chemicals in their environment can show us how receptor protein structures relate to ligand binding, how nervous systems process complex information, and how chemosensory systems and genes evolve.

Dances as windows into insect perception.

Experimental psychologists working with humans have a fundamental advantage over scientists studying the behaviour of other animals. This is because human subjects can give a verbal account of their experience. For example, they can report: ‘These two lights of different colour look equally bright’ or ‘This object looks further away than that one’. Such direct reports facilitate studying how information from the sensory periphery, that is, the sense organs that actually interface with the environment, is processed in the brain.

Drosophila gustatory receptors: from gene identification to functional expression

Recent years have seen long-awaited progress in understanding of the molecular mechanisms of taste perception in insects. The breakthrough came in the early 2000 with the identification of a novel family of candidate gustatory receptor (Gr) genes in the first release of the Drosophila melanogaster genome sequence. The 60 Gr genes are expressed in the subsets of gustatory neurons in the fly’s taste organs and, without exception, encode heptahelical G protein-coupled receptors (GPCRs). Here I review our current knowledge about Gr genes and their products focusing on the newly emerging information regarding the function of the Gr-encoded proteins.

Behavioural-analytical studies of the role of head movements in depth perception in insects, birds and mammals.

In this review, studies of the role of head movements in generating motion parallax which is used in depth perception are examined. The methods used and definitiveness of the results vary with the animal groups studied. In the case of insects, studies which quantify motor outputs have provided clear evidence that motion parallax evoked by head movements is used for distance estimation and depth perception. In the case of birds and rodents, training studies and analyses of the head movements themselves have provided similar indications. In the case of larger mammals, due to a lack of systematic experiments, the evidence is less conclusive.

Insects – a mistake in God's creation? Tharu farmers' perception and knowledge of insects: A case study of Gobardiha Village Development Committee, Dang-Deukhuri, Nepal

Recent trends in agriculturalresearch and development emphasize the need forfarmer participation. Participation not onlymeans farmers' physical presence but also theuse of their knowledge and expertise.Understanding potentials and drawbacks of theirlocal knowledge system is a prerequisite forconstructive collaboration between farmers,scientists, and extension services.An ethnoentomological study, conducted in aTharu village in Nepal, documents farmers'qualitative and quantitative knowledge as wellas perceptions of insects and pest management,insect nomenclature and classification, andissues related to insect recognition and localbeliefs. The study offers a basis to improvepest management programs in terms of efficacyand acceptance. It demonstrates, for instance,that a concept of pests and beneficials isvirtually missing in traditional farmingcommunities and that the Tharu folkclassification profoundly differs from thescientific classification, but is not radicallydifferent from other folk entomologicalsystems. Insects belong to the taxa calledkiraa consisting of arthropods andnon-arthropods that interact with humans. Theyare classified in several overlappinghierarchies where locomotion and human impactplay major roles while morphological criteriaare almost irrelevant. Recognition ofkiraa, however, is dominated by agriculturalaspects followed by physiological-behavioral,ecological, and human-directed features.Morphological criteria play a minor role. Innomenclature, however, the insects' physicalappearance is more important than otherfeatures. The study further shows that male andfemale farmers have different perceptions ofkiraa.The insect-related knowledge system of theTharu has prevented farmers from using modernpesticides in the past. In the course ofmodernization, however, some aspects of theirknowledge system could become obsolete andprove disadvantageous to their livelihood andagro-ecosystems.

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina of Papilio butterflies.

Using imaging polarimetry, we have measured some typical reflection-polarization patterns of plant surfaces (leaves and flowers) under different illuminations. Using a quantitative model to determine photon absorptions in the weakly polarization-sensitive (PS approximately 2) photoreceptors of Papilio butterflies, we have calculated the influence of reflection polarization on the colours of leaves and flowers perceived by PAPILIO: Compared with a retina containing polarization-blind colour receptors, the colour loci of specularly reflecting and, thus, strongly polarizing areas on a plant are slightly shifted, which could cause the perception of false colours. However, the colour of specularly reflecting surfaces is strongly masked by white glare, which may prevent the perception of polarization-induced hue shifts. Although the perception of polarizational false colours by Papilio butterflies was previously demonstrated with artificial, strongly colour-saturated and totally linearly polarized stimuli, we expect that the weak polarization sensitivity of Papilio photoreceptors hardly influences colour perception under natural conditions.

Floral Symmetry and Its Role in Plant-Pollinator Systems.

Floral symmetry has a relevant status in the study of both pollination biology and animal behavior. In this work, a brief review and classification of symmetry types in flowers is provided as a basis for understanding the role of floral symmetry in pollination phenomena. We focus on insects as a fundamental group of pollinators, and we discuss symmetry from the perspective of insect perception. We conclude that symmetry is a specific cue with a signal value that is perceived by insect pollinators. A simple nervous system, such as that of honeybees, is capable of an extremely flexible and adaptive processing of symmetry. Performances consistent with categorization and concept building may be observed, provided that appropriate learning paradigms are employed. Perfectly symmetrical flowers might signal a high quality and/or quantity of nectar or pollen to pollinators that, in turn, might exert strong selection pressure on symmetric features. However, coadaptation arguments in the strict sense are not adequate because it is impossible to determine whether the insect's capacity to perceive symmetry is younger or older than is the origin of flower symmetry.

Visually Controlled Locomotion: 40 years Later

Gibson's article, Visually Controlled Locomotion and Visual Orientation in Animals(1958/this issue), is the leading statement of a nonrepresentational, information-based approach to visual control. The core ideas he introduced 40 years ago resurface, explicitly or implicitly, in much contemporary work on perception and action in humans, insects, robots, and autonomous agents. The purpose of this special issue is to assess the continuing pertinence of these insights and illustrate current directions in research on visually controlled locomotion. In this article, I locate the 1958 article in the context of Gibson's emerging theory of perception, contrast information-based control with standard model-based and cybernetic control architectures, evaluate the current status of Gibson's visual control formulae, and situate visual control within an informational-dynamical approach to agent-environment systems. Locomotion is a biologically basic function, and if that can be accounted for then the problem of human space perception may appear in a new light. The question, then, is how an animal gets about by vision.

Neurobiology of the gustatory systems of Drosophila and some terrestrial insects.

Insects have been favorites for the study of taste perception in the last few decades. They have been used for anatomical, behavioral, developmental, genetic, and physiological studies related to gustation and feeding response. Several genes known to affect the formation of gustatory sensilla or alter the feeding behavior of insects such as Drosophila are known. Studies related to signal transduction, coding of gustatory information, and the nature and constitution of genes involved in taste perception have also been taken up with insects in recent years. The understanding of basic mechanisms of taste perception in insects is likely to lead to better management of useful as well as harmful insects.

Seeing is not believing: Insects as symptoms not cause

Recent studies of indigenous forest decline in New Zealand suggest insects and their damage, although highly conspicuous at this time of rapid ecological change, are symptoms rather than causes of the process which is underway. It is suggested that to focus on the contributing rather than causative factors, not only leads to a poor understanding of the process itself but reinforces the perception of insects as damaging pests rather than beneficial agents of change.

Insect perception of illusory contours

The human visual system sees an illusory contour where there is a fault line across a regular striped pattern. We demonstrate that bees respond as if they see the same illusory contour. There is also a type of neuron in the lobula of the dragonfly optic lobe which responds directionally to motion of the illusory contour as if to an edge or line. Apparently insects have a mechanism that sees illusory contours and therefore assists in the demarcation of edges and objects at places where local contrast falls to zero at an edge, or where one textured object partially obscures another. These results suggest that insect vision, although spatially crude and low in processing power, sees separate objects by similar mechanisms to our own.

Distance Perception in Insects

motor agility enigmatic. Unlike vertebrates, insects have immobile eyes with fixed-focus op tics. The absence of eye movements implies that the range of an object cannot be inferred from the extent to which the directions of gaze of the two eyes must converge to view the object. The inability of an insect eye to change focus means that the dis tance to an object cannot be esti mated by monitoring the refractive power that is required to bring the ?mage of the object into focus on the retina. Compared with human eyes, the eyes of insects are positioned much closer together, and possess much poorer spatial acuity, so the precision with which insects could estimate range through binocular stereopsis?even if they possessed the requisite neural apparatus? would be much poorer and re stricted to relatively small dis tances.1 So far, the praying mantis is the only insect in which stereopsis has been demonstrated unequivo cally.2 It has widely separated eyes, and uses stereoscopic cues to deter

Effects of background pattern on insect perception of webs spun by orb-weaving spiders

Recent studies show that many insects are able to see spider webs and avoid them. The orbspinning spiders and their close relatives are an abundant and diverse group of predators that make use of a variety of habitats and light environments. A combination of field and laboratory approaches was used to explore the effects of light environment, silk reflectance and background pattern on insect perception of spider webs. Field experiments showed that in dim visual habitats, background patterns have no significant effect on insect perception of webs but in bright visual habitats, patterns behind webs decreased the ability of insects to see and avoid them. In the laboratory Drosophila melanogaster Meigen have more difficulty seeing brightly lit webs when they are suspended close to backgrounds of high spatial frequencies than when webs are suspended in front of distant backgrounds or of low spatial frequencies. When Drosophila are confronted with webs characterized by low reflectivity, however, they are unable to see and avoid them, regardless of light level or background spatial pattern. Web visibility results from a series of complex interactions among the reflectance properties of silks, web architecture, background pattern, ambient light level and the peculiar visual physiology of the approaching insect.

Contemporary frontiers in insect semiochemical research

Recent advances in analytical chemistry coupled with more definitive behavioral analyses have allowed more rigorous identification of many insect pheromones. This, in turn, has increased our understanding of the roles of pheromones in mediating insect behavior. Other semiochemicals that mediate insect behavior include those that enable parasitic and predatory insects to locate their hosts or prey. These may be produced by the host insects or by the plant on which they feed. Additionally, there are pheromones and plant-produced seminochemicals that regulate insect oviposition, a critical phase in the life cycle of insects. The challenge to chemists and biologists is to explore these areas to find new environmentally safe methods to control insect pests. One of the newer strategies used to investigate these semiochemicals is the study of the biochemistry of pheromone production and semiochemical perception in insects. These types of studies may reveal weak links in these systems that can be exploited to develop new, more effective and environmentally safe control methods.

Bitten by the Insect Bug

I must admit that I do not like insects. I try to avoid them as much as possible, not only by swatting away at any fly I see, but also by pushing aside unread most writing on insects. There seem to be two reasons for my aversion. One is early memories of my mother on cricket patrol on summer evenings. Insects were something to be crushed if they dared venture inside the house. Spiders, worms and everything else classified as creepy crawlies received the same treatment-rapid extermination. It never dawned on me that some people thought of caterpillars as beautiful or spent hours observing the behavior of beetles. Nor did my estimation of invertebrates in general improve when I became a biology major. Invertebrates were disgusting rather than interesting organisms since they were usually presented as pickled specimens floating, and often decomposing, in foul-smelling fluid. To make them even more distasteful, they were used merely as problems in classification. What organisms had radical versus bilateral symmetry? What differentiated arachnids from arthropods, or roundworms from flatworms? But even as inveterate an invertebrate hater as myself cannot avoid sixlegged creatures completely. Insects are everywhere, abundant both in quantity and variety. As John Alcock has written: When you consider that there are several million species of insects, each wonderfully distinctive, and fewer than 10,000 species of birds, it is strange that there are millions of bird watchers but only thousands of insect enthusiasts. It occurred to me recently that among this relatively small band of enthusiasts are a large number of good writers, too good for even me to resist. Bernd Heinrich's In a Patch of Fireweed (1984), Karl von Frisch's Bees (1950), and Edward 0. Wilson's The Insect Societies (1971) immediately come to mind. But above them all stand two books which I found tremendously fascinating, and which changed my perception of insects. They are a collection of the writings of J. Henri Fabre, edited by Edwin Way Teale (1949), and Howard Ensign Evans's Life on a Little-known Planet (1984). These books have not made me love insects-just yesterday I crushed a beetle that crawled up my arm, rather than trying to classify it or observe its behavior. But these books have given me an appreciation for such creatures, at least on an intellectual level. From now on, when I discuss insects in class it will be less out of a sense of duty and more with a sense of wonder. The writings of Fabre and Evans are very different from each other. Though they both dedicated their lives

Orchids, bilateral symmetry and insect perception

The basic characteristics of orchids, possessing the greatest number of complex floral images of any Angiosperm family, are reviewed. Bilateral symmetry (zygomorphy) is shown by use of information theory techniques to give much greater possibilities for the transmission of visually mediated information than radial symmetry. The difference in information content is further enhanced by motion. The analysis is offered as evidence that the evolution of diversity in complex images, if effected by the unique behavioral specificity of pollinators known as “flower constancy”, is most economically explained by hypothesizing recognition and storage of the total image (“gestalt”) in the agents of natural selection.

Specificity and molecular features of an insect attractant in a Drosophila mutant.

SEVERAL attractants and repellents which are highly specific for a given species or sex have been identified in the last decade. Although much effort has been concentrated on demonstrating the molecular basis of odour perception in insects, the mechanisms involved are still far from clear1. As the complicated network of cellular function in chemotaxis has been successfully analysed in bacteria, using a mutation which indicates alteration of one element involved at a time, a similar approach is expected to be fruitful in studies of the olfactory system2,3. Drosophila is the insect of choice for such studies because of its large stock of marker genes and crossing-over suppressors which are essential for the isolation of induced olfactory mutants. Recent success in the isolation of behavioural mutants of Drosophila has thrown light on this subject4. I shall describe here the properties of an olfactory mutant of Drosophila melanogaster and the molecular characteristics of the odours to which the mutant responded specifically.