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PubMed1997

Stinging insect allergies. Assessing and managing.

BACKGROUND: Mortality secondary to insect sting anaphylaxis, though uncommon in this country, is a genuine risk to patients with venom hypersensitivity. A number of non specific and specific preventive measures are available to minimise this risk. They include proper patient counselling regarding sting avoidance and the use of self injectable adrenaline, as well as venom specific immunotherapy. OBJECTIVE: This article attempts to review the spectrum of insect sting reactions, their appropriate assessment and subsequent management. Anaphylaxis is particularly emphasised with regard to first aid treatment and subsequent prevention. DISCUSSION: The most common causes of insect stings in Australia are bees and wasps. Insect sting reactions cover a spectrum of responses, from normal to anaphylactic. Immunotherapy is indicated in those patients who experience anaphylactic responses. The presence of venom specific IgE must be demonstrated before commencing immunotherapy. Venom sensitive patients should be educated in anaphylaxis first aid with adrenaline self injectable syringes.

Adrenergic Agonists↗
PubMed2006

Function and evolution of a gene family encoding odorant binding-like proteins in a social insect, the honey bee (Apis mellifera).

The remarkable olfactory power of insect species is thought to be generated by a combinatorial action of two large protein families, G protein-coupled olfactory receptors (ORs) and odorant binding proteins (OBPs). In olfactory sensilla, OBPs deliver hydrophobic airborne molecules to ORs, but their expression in nonolfactory tissues suggests that they also may function as general carriers in other developmental and physiological processes. Here we used bioinformatic and experimental approaches to characterize the OBP-like gene family in a highly social insect, the Western honey bee. Comparison with other insects shows that the honey bee has the smallest set of these genes, consisting of only 21 OBPs. This number stands in stark contrast to the more than 70 OBPs in Anopheles gambiae and 51 in Drosophila melanogaster. In the honey bee as in the two dipterans, these genes are organized in clusters. We show that the evolution of their structure involved frequent intron losses. We describe a monophyletic subfamily of OBPs where the diversification of some amino acids appears to have been accelerated by positive selection. Expression profiling under a wide range of conditions shows that in the honey bee only nine OBPs are antenna-specific. The remaining genes are expressed either ubiquitously or are tightly regulated in specialized tissues or during development. These findings support the view that OBPs are not restricted to olfaction and are likely to be involved in broader physiological functions.

Amino Acid Sequence↗
PubMed1998

Distribution of GABA-like immunoreactive neurons in insects suggests lineage homology.

Gamma-aminobutyric acid (GABA) is an important inhibitory neurotransmitter in vertebrates and invertebrates (Sattelle [1990] Adv. Insect Physiol. 22:1-113). The GABA phenotype is lineally determined in postembryonic neurons in the tobacco hawkmoth, Manduca sexta (Witten and Truman, [1991] J. Neurosci. 11:1980-1989) and is restricted to six identifiable postembryonic lineages in the moth's thoracic hemiganglia. We used a comparative approach to determine whether this distinct clustering of GABAergic neurons is conserved in Insecta. In the nine orders of insects surveyed (Thysanura, Odonata, Orthoptera, Isoptera, Hemiptera, Coleoptera, Diptera, Lepidoptera, and Hymenoptera), GABA-like immunoreactive neurons within a thoracic hemiganglion were clustered into six distinct groups that occupied positions similar to the six postembryonic lineages in Manduca. On the basis of cell body position and axon trajectories, we suggest that these are indeed homologous lineage groups and that the lineal origins of the GABAergic cells have been very conservative through insect evolution. The distinctive clustering of GABA-positive cells is shared with crustaceans (Mulloney and Hall [1990] J. Comp. Neurol. 291:383-394; Homberg et al. [1993] Cell Tissue Res. 271:279-288) but is not found in the centipede Lithobius forficulatus. There is a two- to threefold increase in numbers of thoracic neurons between the flightless Thysanura and the most advanced orders of insects. Using the GABA clusters as indicators of specific lineages, we find that only selected lineages have significantly contributed to this increase in neuronal numbers.

Animals↗
PubMed1999

Structure, development, and evolution of insect auditory systems.

This paper provides an overview of insect peripheral auditory systems focusing on tympanate ears (pressure detectors) and emphasizing research during the last 15 years. The theme throughout is the evolution of hearing in insects. Ears have appeared independently no fewer than 19 times in the class Insecta and are located on various thoracic and abdominal body segments, on legs, on wings, and on mouth parts. All have fundamentally similar structures-a tympanum backed by a tracheal sac and a tympanal chordotonal organ-though they vary widely in size, ancillary structures, and number of chordotonal sensilla. Novel ears have recently been discovered in praying mantids, two families of beetles, and two families of flies. The tachinid flies are especially notable because they use a previously unknown mechanism for sound localization. Developmental and comparative studies have identified the evolutionary precursors of the tympanal chordotonal organs in several insects; they are uniformly chordotonal proprioceptors. Tympanate species fall into clusters determined by which of the embryologically defined chordotonal organ groups in each body segment served as precursor for the tympanal organ. This suggests that the many appearances of hearing could arise from changes in a small number of developmental modules. The nature of those developmental changes that lead to a functional insect ear is not yet known.

Animals↗
PubMed1999

Larval antennal sensilla in water-living insects.

An overview of larval antennal sensilla in hemimetabolous and holometabolous water-living insects is given by updating current knowledge on the fine structure of these sensory systems. In the absence of successful electrophysiological studies, the possible function of sensilla is deduced from their architecture. Various kinds of sensilla are described in hemimetabolous insects, such as Ephemeroptera, Odonata, and Plecoptera, and holometabolous insects, such as Diptera Nematocera (Culicidae, Simuliidae, Psychodidae, Chaoboridae) and Trichoptera. Their possible function in responding to stimuli from the freshwater environment is illustrated and discussed. The importance of sensilla as taxonomic and phylogenetic traits is reported in Baetidae (Ephemeroptera) and in Diptera Nematocera. Some homologies outlined in Diptera Nematocera give evidence of a link between species, such as Chaoboridae and Psychodidae, whose antennae are highly modified, prehensile in the former and very reduced in the latter. Particular features, such as cuticle without pores in chemosensory sensilla and naked perikarya, are so far found exclusively in some water-living arthropods, thus reflecting a possible adaptation to the aquatic habitat. The structure of sensilla and chloride cells, which have a similar external morphology, is presented and discussed in various insect groups, considering the possible derivation of the chloride cells from sensilla.

Animals↗
PubMed1996

Comparative analysis of glucose and glutamine metabolism in transformed mammalian cell lines, insect and primary liver cells.

Glucose and glutamine metabolism in several cultured mammalian cell lines (BHK, CHO, and hybridoma cell lines) were investigated by correlating specific utilization and formation rates with specific maximum activities of regulatory enzymes involved in glycolysis and glutaminolysis. Results were compared with data from two insect cell lines and primary liver cells. Flux distribution was measured in a representative mammalian (BHK) and an insect (Spodoptera frugiperda) cell line using radioactive substrates. A high degree of similarity in many aspects of glucose and glutamine metabolism was observed among the cultured mammalian cell lines examined. Specific glucose utilization rates were always close to specific hexokinase activities, indicating that formation of glucose-6-phosphate from glucose (catalyzed by hexokinase) is the rate limiting step of glycolysis. No activity of the key enzymes connecting glycolysis with the tricarboxylic acid cycle, such as pyruvate dehydrogenase, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase, could be detected. Flux distribution in BHK cells showed glycolytic rates very similar to lactate formation rates. No glucose- or pyruvate-derived carbon entered the tricarboxylic acid cycle, indicating that glucose is mainly metabolized via glycolysis and lactate formation. About 8% of utilized glucose was metabolized via the pentose phosphate shunt, while 20 to 30% of utilized glucose followed pathways other than glycolysis, the tricarboxylic acid cycle, or the pentose phosphate shunt. About 18% of utilized glutamine was oxidized, consistent with the notion that glutamine is the major energy source for mammalian cell lines. Mammalian cells cultured in serum-free low-protein medium showed higher utilization rates, flux rates, and enzyme activities than the same cells cultured in serum-supplemented medium. Insect cells oxidized glucose and pyruvate in addition to glutamine. Furthermore, insect cells produced little or no lactate and were able to channel glycolytic intermediates into the tricarboxylic acid cycle. Metabolic profiles of the type presented here for a variety of cell lines may eventually enable one to interfere with the metabolic patterns of cells relevant to biotechnology, with the hope of improving growth rate and/or productivity.

Animals↗
PubMed2000

Characterization of nicotinic acetylcholine receptors from the insects Aphis craccivora, Myzus persicae, and Locusta migratoria by radioligand binding assays: relation to thiamethoxam action.

Thiamethoxam, a new neonicotinoid insecticide acting at nicotinic acetylcholine receptors, was characterized in competition binding assays with [3-H]-imidacloprid, a specific nicotinic ligand, using membranes from the aphids Aphis craccivora and Myzus persicae, and from the locust Locusta migratoria. In all insects, Scatchard analysis suggested two binding sites for imidacloprid with Kd values in the range of 1 nM and 10 nM, respectively. The Hill values were significantly below 1 (range of 0.63 to 0.85). In contrast to imidacloprid and nicotine, the potency of thiamethoxam to displace [3-H]-imidacloprid varied considerably among these insects. Thiamethoxam was more active than nicotine on Aphis receptors but 100-fold less in Locusta, a nontarget insect. Comparable relations were found to nithiazine. In Myzus, the inhibition curve for thiamethoxam was shallow. This suggested a heterogeneous receptor population displaying a range of binding affinities to thiamethoxam in this aphid. In all three insects, the other neonicotinoid insecticides studied competed with [3-H]-imidacloprid in the same order: thiacloprid > imidacloprid > or = acetamiprid > nitenpyram. N-Methylation of imidacloprid strongly reduced the affinity to the imidacloprid site, whereas N-demethylation of thiamethoxam resulted in a comparable increase of affinity. Supplementary assays were performed with (-)-[3-H]-nicotine and [3-H]-alpha-bungarotoxin on locust membranes. Overall, the data suggested that the outstanding insecticidal properties of thiamethoxam may be due to either a different binding site on nicotinic receptors, or receptor isoforms, or specific pharmakokinetic behavior, rather than to exceptional affinity to one of the examined binding sites.

Animals↗
PubMed2000

Proteolytic activation of canatoxin, a plant toxic protein, by insect cathepsin-like enzymes.

Canatoxin is a protein isolated from jackbean (Canavalia ensiformis), seeds. Injected intraperitoneally, the toxin is lethal to mice but it is inactive if given orally. Canatoxin is also lethal when fed to insects with cathepsin-based digestion while insects with trypsin-based digestion are not affected. The hypothesis that canatoxin is proteolytically activated by cathepsins was investigated. Experiments were performed with 4(th) instar and adult Rhodnius prolixus fed meals containing canatoxin (2.5 microg/mg weight body). While 100% of nymphs died, no effect was observed in adults. Hemolymph taken from nymphs and adults showed the presence of canatoxin's proteolytic fragments. Reduced lethality was seen in R. prolixus 4(th) instars fed meals containing canatoxin and inhibitors of cathepsin enzymes, E-64 (2.0 microM) or Pepstatin-A (2. 0 microM). In another approach, canatoxin was digested in vitro with enzymes from the bruchid, Callosobruchus maculatus, and the resulting peptides were tested in R. prolixus. Three groups of toxic peptides (8,000-12,000 kD range) were separated by gel-filtration. When these peptides were fed to the insects simultaneously with the cathepsin inhibitors, no protective effect was seen. These results confirm the proteolytic activation of canatoxin by insect cathepsin-like enzymes to produce entomotoxic peptide(s). Furthermore, our data point towards overlooked differences in the digestive physiology of distinct life stages of R. prolixus. Arch.

Animals↗
PubMed2000

Mineral content of insect infested stored legumes treated with edible oils.

Mineral content of three insect (pulse beetle, Callosobruchus chinensis L.) infested legumes viz. chick pea, mung pea and pigeon pea stored for six months and treated with three edible oils viz. groundnut, mustard and coconut oil has been studied. With increase in storage period significant increase in calcium, phosphorus and iron content of untreated legumes was observed. After three months of storage slight increase in three minerals was observed in the legumes treated with coconut oil which continued till the end of sixth months as compared to other two oil treated counterparts. The storage period was associated with insect infestation which in turn influenced the mineral content of legumes. Ground nut and mustard oils were able to protect legumes for six months against insect infestation when applied in small amounts (0.5%). Whereas coconut oil had protective effect against insect infestation for four months only.

Animals↗
PubMed1999

Cross-talk between the signal pathways for pathogen-induced systemic acquired resistance and grazing-induced insect resistance.

Reducing phenylpropanoid biosynthesis in transgenic tobacco compromises systemic acquired resistance (SAR) to tobacco mosaic virus, while increasing phenylpropanoid biosynthesis enhances SAR. Surprisingly, transgenic tobacco plants compromised in SAR exhibit more effective grazing-induced systemic resistance to larvae of Heliothis virescens, whereas induced insect resistance is compromised in transgenic plants with elevated phenylpropanoid levels. Levels of the phenylpropanoid-derived signal salicylic acid are directly correlated with overall phenylpropanoid biosynthesis in this series of transgenic plants. Moreover, while pathogen-induced SAR is almost completely compromised in salicylic acid-deficient plants expressing the bacterial nahG salicylate hydroxylase gene, these plants show enhanced grazing-induced insect resistance compared to wild-type. Hence, suppression of grazing-induced insect resistance is mediated at least in part by salicylic acid and likely reflects salicylic acid inhibition of the synthesis and action of the wound signal jasmonic acid. We propose that the dual functions of salicylic acid contribute to a signal poise which constrains constitutive expression of disease and insect resistance mechanisms, and reciprocally switches their selective activation.

Animals↗
PubMed2002

Resistance of the insect cell line IPLB-LdFB to salsolinol-induced apoptosis.

Apoptosis is a form of cell death that is manifested in Parkinson's disease (PD) and certain other neurodegenerative disorders. Metabolites of salsolinol (SAL), an intraneuronal, dopamine-derived tetrahydroisoquinoline (TIQ), have been shown to induce apoptosis in human dopaminergic neuroblastoma cells, implicating these molecules as causative or contributory factors in the selective killing of nigrostriatal dopaminergic neurons, a cardinal manifestation of Parkinson's disease. Since insects employ dopamine and related catecholamines in a variety of processes including cuticular sclerotization and cellular immune reactions, it was of interest to know how insect cells metabolized exogenous SAL. Propidium iodide staining combined with flow cytometry showed that IPLB-LdFB cells from Lymantria dispar exhibited no significant (P < 0.05) increase in apoptosis when incubated for 48 h with concentrations of SAL ranging from 10 microM to 1 mM. A significant increase in apoptosis (P < 0.05) was observed in cell cultures containing the highest concentration of SAL tested (5 mM), but only 12.4% of the cells manifested this form of cell death. High pressure liquid chromatography with electrochemical detection (HPLC-ED) was used to document the production of two potentially cytotoxic quinonoids generated during the autoxidation of SAL, a reaction that was found to be significantly (P < 0.05) enhanced by peroxidase. The resistance of IPLB-LdFB cells to SAL-induced apoptosis is attributed to the ability of these insect cells to metabolize and/or detoxify such dopamine-derived catecholic TIQs. Thus, the biochemical pathways employed by insect cells in these processes may be of considerable interest to individuals investigating certain neurodegenerative disorders.

Animals↗
PubMed2002

Significance of penetration, excretion, and transovarial uptake to toxicity of three insect growth regulators in predatory lacewing adults.

Topical treatment of the predatory lacewing adults, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) before and after the onset of oviposition with diflubenzuron (DFB) at doses based on the maximum field recommended concentration resulted in a total inhibition of egg hatch due to death of the embryo. In contrast, pyriproxyfen (PYR) and tebufenozide (TEB) did not affect fecundity and egg fertility. To explain these differences in toxicity, the patterns of penetration through the cuticle, distribution inside the insect body, and excretion were studied using [(14)C]-labeled isotopes of each insect growth regulator (IGR). Penetration of DFB and TEB reached about 16 and 26% in 7 days, whereas 88% of PYR had penetrated in 24 h. However, the rate of excretion for PYR was very high, compared to that of DFB and TEB. Low amounts of absorbed radioactivity were recovered from the female body with the exception of DFB, the ovaries and the eggs deposited during a week. DFB and PYR concentration reached a peak in the eggs deposited at the fourth and second day after treatment, respectively. The current data indicate the importance of penetration through the insect cuticle. However, other mechanisms are likely to be involved in the selectivity of the current IGRs towards this beneficial insect.

Animals↗
PubMed2006

Comparative structure-activity analysis of insect kinin core analogs on recombinant kinin receptors from Southern cattle tick Boophilus microplus (Acari: Ixodidae) and mosquito Aedes aegypti (Diptera: Culicidae).

The systematic analysis of structure-activity relationships of insect kinins on two heterologous receptor-expressing systems is described. Previously, kinin receptors from the southern cattle tick, Boophilus microplus (Canestrini), and the dengue vector, the mosquito Aedes aegypti (L.), were functionally and stably expressed in CHO-K1 cells. In order to determine which kinin residues are critical for the peptide-receptor interaction, kinin core analogs were synthesized as an Ala-replacement series of the peptide FFSWGa and tested by a calcium bioluminescence plate assay. The amino acids Phe(1) and Trp(4) were essential for activity of the insect kinins in both receptors. It was confirmed that the pentapeptide kinin core is the minimum sequence required for activity and that the C-terminal amide is also essential. In contrast to the tick receptor, a large increase in efficacy is observed in the mosquito receptor when the C-terminal pentapeptide is N-terminally extended to a hexapeptide. The aminoisobutyric acid (Aib)-containing analog, FF[Aib]WGa, was as active as superagonist FFFSWGa on the mosquito receptor in contrast to the tick receptor where it was statistically more active than FFFSWGa by an order of magnitude. This restricted conformation Aib analog provides information on the conformation associated with the interaction of the insect kinins with these two receptors. Furthermore, the analog FF[Aib]WGa has been previously shown to resist degradation by the peptidases ACE and nephrilysin and represents an important lead in the development of biostable insect kinin analogs that ticks and mosquitoes cannot readily deactivate.

Aedes↗
PubMed1993

A functional analysis of the P-element gene-transfer vector in insects.

A P-element mobility excision assay was used to determine if non-drosophilid insects could support P gene vector function. Present studies included the testing of Muscids, Sphaerocerids, and Phorids, none of which were able to support P mobility. A new excision indicator plasmid was developed allowing the detection and recovery of virtually all P-element excision products. The frequency and sequence analysis of excision products from Drosophila melanogaster and another drosophilid, Chymomyza procnemis, indicated both quantitative and qualitative differences in the activity of transposase. The quantitative relationships observed in the original assay were maintained, and qualitative differences in transposase activity were reflected in the sequence of the empty donor sites. The results suggest that host factors are involved in cutting and ligating P-element DNA during excision, with transposase facilitating these processes. Possible limitations on P mobility by abnormal transposase transcript processing were tested in Anastrepha suspensa using transposase-encoding plasmids having deleted intron sequences. A transposase cDNA supported normal P excision in D. melanogaster, and a low level of mobility in A. suspensa. Possible applications of gene transfer in insects are presented, in particular methods to genetically sterilize and sex insects for the sterile-insect technique.

Animals↗
PubMed1995

Phototoxicity of plant secondary metabolites: insect and mammalian perspectives.

Phototoxic chemicals produced by plants have been studied in a number of contexts, most notably as protective agents against mammalian and insect herbivores. Although there are commonalities in the responses of these two groups of herbivores to plant phototoxins, there are differences as well. Whereas a greater range of chemical classes has been demonstrated to display phototoxicity against insects, considerably more information is available on symptomology of phototoxicity and mechanisms of action in mammals. The commonalities include alterations in behavior following ingestion, notably photophobia, disruption of integumentary integrity following contact or ingestion, and metabolic detoxification following ingestion, in the case of furanocoumarins involving cytochrome P450 monooxygenases. Not yet known to exist in insects are phototoxin-mediated effects on sensory (particularly visual) systems and phototoxicity resulting from abnormal chlorophyll metabolism. In order to gain greater understanding of the ecological significance of phototoxin-mediated plant defense against both insects and mammals, there is a need for more studies centered on natural associations.

Animals↗
PubMed2005

Improvement of the production of GFPuv-beta1,3-N-acetylglucosaminyltransferase 2 fusion protein using a molecular chaperone-assisted insect-cell-based expression system.

A stable Tn-5B1-4 insect cell line co-expressing the recombinant GFPuv-beta1,3-N-acetylglucosaminyltransferase 2 (GFPuv-beta3GnT2) protein fused to a melittin signal sequence with a lectin-like molecular chaperone, human calnexin (hCNX) or human calreticulin (hCRT), was constructed. The expression of either of these molecular chaperones is under the control of a weak promoter, OpMNPV IE2, while that of GFPuv-beta3GnT2 is under the control of Bombyx mori actin promoter. This co-expression system was compared between two different insect cell-baculovirus expression systems: (1) co-infection of the recombinant baculovirus containing a molecular chaperone (AcNPV-hCNX or -hCRT) with a recombinant baculovirus containing GFPuv-beta3GnT2 fused with the melittin signal sequence (AcNPV-me-GGT); (2) infection of AcNPV-me-GGT to a stably expressing cell line for either hCNX or hCRT. In the co-infection system, the intracellular GFPuv-beta3GnT2 expression level was low because of the improved secretion level ratio of the fusion protein, due to the chaperone expression. In the case of infection to the stably expressing cell line for a chaperone, the extracellular GFPuv-beta3GnT2 expression level was similar to the intracellular expression level. This suggests that the amount of expressed chaperone is not sufficient to process beta3GnT2. On the other hand, the co-expression system produced an extracellular beta3GnT activity of 22-23 mU/mL, which was approximately 3.5- and 11-fold higher than those of the stable expression of the fusion gene without the chaperone and the conventional BES with the addition of protease, respectively. The secretion level ratio of the fusion protein of this system increased to 82%, which was approximately 1.5-fold that of any other expression system investigated thus far. These results indicate that the ratio of the expression level of the target gene to that of the chaperone gene may be an important factor in maximizing the production of a target protein. The molecular-chaperone-assisted expression system using a stably transformed insect cell line offers promising prospects for the efficient production of recombinant secretory proteins in insect cells.

Animals↗
PubMed1992

Expression and partial characterization of rat protein kinase C-delta and protein kinase C-zeta in insect cells using recombinant baculovirus.

Expression of rat protein kinase C-delta (PKC-delta) and PKC-zeta in insect cells using recombinant baculovirus resulted in the production of proteins with a molecular size of approximately 76 kD and 78 kD, respectively, as determined by immunoblotting with subtype-specific antisera. Although the PKC-zeta cDNA encoded for 592 amino acids, a 76 kD protein was also generated by in vitro transcription/translation. Extracts of cells expressing PKC-delta were able to bind phorbol ester to levels comparable to extracts of cells expressing PKC-alpha. No phorbol ester binding was, however, detected in insect cell extracts expressing PKC-zeta. However, similar levels of protein kinase activity were detected in lysates of cells expressing PKC-delta or PKC-zeta when protamine sulfate was used as exogenous substrate. Compared to protamine sulfate, both, myelin basic protein (MBP) or histone, were poor substrates for PKC-delta and PKC-zeta. In contrast to PKC-zeta, the PKC-delta enzyme activity phosphorylated MBP or histone in a phosphatidylserine-(PS)/diacylglycerol(DG)-dependent manner, albeit not to the same extent as PKC-alpha. Lack of stimulation of the enzyme activity of PKC-zeta by PS/DG, was confirmed by endogenous phosphorylation of insect cell proteins by PKC-zeta, whereas several insect cell proteins were phosphorylated by PKC-delta in a PS/DG-dependent manner, including a protein of 78 kD. Our data demonstrate that the 76 kD PKC-zeta, in contrast to PKC-delta, is unable to bind phorbol esters and displays a protein kinase activity that is independent of PS or PS/DG. In addition, staurosporine was about 2-4 order of magnitudes less effective in inhibiting the protein kinase activities of PKC-delta and PKC-zeta when compared to PKC-alpha.

Alkaloids↗
PubMed1993

Synaptic organization and development of the antennal lobe in insects.

Many insects possess a highly developed sense of smell. This paper summarizes the cellular and synaptic organization of the antennal (olfactory) lobe of the insect brain and then reviews morphological and fine-structural aspects of the development of the lobe. Visualization of synapses between classes of neurons identified by physiological, morphological, or transmitter-cytochemical properties has provided insights into arrangements of contacts and their possible roles in information processing. Studies of development have revealed the requirement for afferent axons from the antenna for the formation of olfactory glomeruli, where virtually all of the synapses in the lobe occur, and have suggested the possibility that glial cells play a role in the instructive influence of the axons on their target neurons in the lobe. The findings reviewed in this paper are primarily from one representative hemimetabolous insect, the American cockroach, and one representative holometabolous insect, a hawkmoth, and comparisons are made with vertebrate systems when appropriate.

Animals↗