Insect Viability Research Articles

Exploring Edible Insects: A Review on Protein Diversity, Extraction Techniques, and Health Benefits.

This study investigates whether edible insects may be used as a sustainable protein source. This study covers insect proteins, their defatting process and extraction, health advantages, economic and environmental impacts, safety considerations, and regulatory aspects. This review also investigates the ecological benefits of insect farming and consumer acceptance of this dietary trend. A systematic search of the pertinent literature was conductedto collect data for this review. Current research examines the effects of using edible insects as functional, sustainable reservoirs of proteins, including protein screening, extraction methods, health benefits, and social recognition. The varied isolation techniques considerably affect protein amount and quality. . This review clarifies the broad spectrum of proteins in edible insects, particularly their nutritional importance and effective extraction methods. The viability of insects as a sustainable source of protein is highlighted by the safety considerations and the interaction of economic and ecological considerations with complex consumer characteristics.

Spinosad‐associated modulation of select cytochrome P450s and glutathione S‐transferases in the Colorado potato beetle, Leptinotarsa decemlineata

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an insect pest that threatens potato crops. Multiple options exist to limit the impact of this pest even though insecticides remain a primary option for its control. Insecticide resistance has been reported in Colorado potato beetles and a better understanding of the molecular players underlying such process is of utmost importance to optimize the tools used to mitigate the impact of this insect. Resistance against the insecticide spinosad has been reported in this insect and this work thus aims at exploring the expression of targets previously associated with insecticide response in Colorado potato beetles exposed to this compound. Amplification and quantification of transcripts coding for cytochrome P450s and glutathione S-transferases were conducted via qRT-PCR in insects treated with varying doses of spinosad and for different time duration. This approach notably revealed differential expression of CYP6a23 and CYP12a5 in insects exposed to low doses of spinosad for 4 has well as modulation of CYP6a13, CYP6d4, GST, GST1, and GST1-Like in insects treated with high doses of spinosad for the same duration. RNAi-based targeting of CYP4g15 and CYP6a23 was associated with marked reduction of transcript expression 7days following dsRNA injection and reduction of the former had a marked impact on insect viability. In general, results presented here provide novel information regarding the expression of transcripts relevant to spinosad response in Colorado potato beetles and reveal a novel target to consider in the development of RNAi-based strategies aimed at this potato pest.

Lethal and Sublethal Effects of Annona spp. Derivatives on Bemisia tabaci MEAM 1 (Hemiptera: Aleyrodidae) in Tomato.

The whitefly Bemisia tabaci(Gennadius) MEAM 1 is one of the main insect species that colonize tomato plants and cause direct and indirect damage. The use of botanical derivatives may be a valuable method of insect control to reduce the inappropriate use of synthetic insecticides on crops. In this study, we evaluated the bioactivity of ethanolic extracts prepared from Annonaceae species compared to that of the commercial insecticides based on acetogenins (Anosom® 1 EC, anonine 10,000 mg L-1) and thiamethoxam (Actara® 250 WG) on eggs, nymphs, and adults of the whitefly in tomato. Initially, the effects of the ethanolic seed extracts of Annona mucosa (Jacq.), Annona muricata L., and Annona sylvatica A.St.-Hil on adult insect behavior were evaluated. The rates of infestation and oviposition deterrence indicated the inhibitory effects of the extract of A. muricata (500 mg L-1). Then, the possible systemic effects of the extracts were evaluated; however, no effects on nymphal development or insect viability were observed. The LC50 and LC90 of the ethanolic extract of A. mucosa seeds at 500 mg L-1 (10.83 and 200.24 mg L-1, respectively) were estimated and were used in ovicidal tests and compared to positive (Actara® 250 WG and Anosom® 1 EC), and negative controls (water: acetone, 1:1 v/v). At LC90, fewer eggs (35.00%) had hatched at 13 days after application than in the other treatments. The results of this study demonstrate the potential use of botanical derivatives of Annona spp. for the management of B. tabaci MEAM 1 in tomato.

The VAChTY49N mutation provides insecticide-resistance but perturbs evoked cholinergic neurotransmission in Drosophila.

Global agriculture and the control of insect disease vectors have developed with a heavy reliance on insecticides. The increasing incidence of resistance, for virtually all insecticides, threatens both food supply and effective control of insect borne disease. CASPP ((5-chloro-1’-[(E)-3-(4-chlorophenyl)allyl]spiro[indoline-3,4’-piperidine]-1-yl}-(2-chloro-4-pyridyl)methanone)) compounds are a potential new class of neuroactive insecticide specifically targeting the Vesicular Acetylcholine Transporter (VAChT). Resistance to CASPP, under laboratory conditions, has been reported following either up-regulation of wildtype VAChT expression or the presence of a specific point mutation (VAChTY49N). However, the underlying mechanism of CASPP-resistance, together with the consequence to insect viability of achieving resistance, is unknown. In this study, we use electrophysiological characterisation of cholinergic release at Drosophila larval interneuron→motoneuron synapses to investigate the physiological implications of these two identified modes of CASPP resistance. We show that both VAChT up-regulation or the expression of VAChTY49N increases miniature (mini) release frequency. Mini frequency appears deterministic of CASPP activity. However, maintenance of SV release is not indicative of resistance in all cases. This is evidenced through expression of syntaxin or complexin mutants (sytx3-61/cpxSH1) that show similarly high mini release frequency but are not resistant to CASPP. The VAChTY49N mutation additionally disrupts action potential-evoked cholinergic release and fictive locomotor patterning through depletion of releasable synaptic vesicles. This observation suggests a functional trade-off for this point mutation, which is not seen when wildtype VAChT is up-regulated.

Maize Stem Response to Long-Term Attack by Sesamia nonagrioides.

Plants defend themselves against herbivores by activating a plethora of genetic and biochemical mechanisms aimed at reducing plant damage and insect survival. The short-term plant response to insect attack is well understood, but less is known about the maintenance of this response over time. We performed transcriptomic and metabolomics analyses in order to identify genes and metabolites involved in the long-term response of maize to attack by the corn borer Sesamina nonagrioides. To determine the role of elicitors present in caterpillar secretions, we also evaluated the response of maize stem challenged with insect regurgitates. The integrative analysis of the omics results revealed that the long-term response in maize is characterized by repression of the primary metabolism and a strong redox response, mainly mediated by germin-like proteins to produce anti-nutritive and toxic compounds that reduce insect viability, and with the glutathione–ascorbate cycle being crucial to minimize the adverse effects of reactive oxygen species (ROS) on the plant. Our results suggest that different defense mechanisms are involved in the long-term response compared to those reported during the early response. We also observed a marginal effect of the caterpillar regurgitates on the long-term defensive response.

BIOLOGIA DE <i>Thaumastocoris peregrinus</i> CARPINTERO E DELLAPÉ (HEMIPTERA: THAUMASTOCORIDAE) EM DEZ ESPÉCIES DE EUCALIPTO

O percevejo-bronzeado-do-eucalipto Thaumastocoris peregrinus é originário da Austrália e foi detectado no Brasil em 2008, causando danos em plantações de eucalipto. O percevejo suga a seiva, principalmente das folhas mais velhas, nas quais se formam pontos cloróticos que, posteriormente, tornam-se manchas bronzeadas. Em casos extremos pode ocorrer desfolhação. Os trabalhos sobre o comportamento do inseto ainda são escassos perante os registros de danos em plantações de eucalipto. Diante disso, avaliou-se a biologia de Thaumastocoris peregrinus em dez espécies de eucalipto, plantadas comercialmente no Rio Grande do Sul. Das espécies oferecidas para alimentação de Thaumastocoris peregrinus, Eucalyptus dunnii foi a que conferiu maior longevidade, número de adultos, ovos e viabilidade aos insetos.

On the discontinuous character of annuity curves. III. Two forms of viability variation in Drosophila melanogaster

The validity of the two-component structure of annuity curves in Drosophila melanogaster (line Canton-S) observed in our previous studies has been confirmed. The structure is formed by a combination of a stable five-phase pattern and the variability of phase duration (the latter determines the variability of insect viability). Both the stable and the variable component were preserved over 60 generations of flies. The unconventional type of variability addressed in the present study exists along with the well-known type of variability related to the stochastic variation of the annuity curves. The variance of viability that characterizes the reaction norm remains unchanged in a series of generations as well. Thus, both types of variability can be classified as genetically determined phenomena.

New approaches to quality control for cultures of insects for rearing

An analytical review of existing methods of quality control for cultures of insects for rearing is presented. It is shown that there is a need to search for new approaches to solving this problem. The suggested methods for quality control for insect cultures are based on the rule of taxis intensity dependence on insect viability level. Testing of new methods of control and prediction of biological material viability was carried out on several breeds of silkworm (Bombyx mori L.) and a laboratory culture of the gypsy moth (Lymantria dispar L.). It was established that the caterpillars of silkworm breeds with high viability show higher chemotaxis intensity. It was found that intensity of taxis manifestation can be considered as a criterion of population condition. Selection of the most promising breeds of silkworm can be carried out at the moment of hatching without expensive rearing. It was shown that testing of neonate caterpillars by chemotaxis intensity provides the control of viability in all stages of insect development. Evaluation of chemotaxis intensity of adult males on female sex pheromone gives the possibility to select the specimens with the highest physiological properties for hybridization as well as to predict viability for progeny. The method of biological material selection by chemotaxis intensity was improved due to decrease the time of selection from 30 to 15 minutes and preliminary starvation of these insects. Positive correlation was evaluated between general viability of silkworm culture and intensity of chemotaxis of neonate larvae to the smell of mulberry leaf during 15 minutes after 12 hours of starvation. A significant increase of viability for silkworm breeds and hybrids was registered using such selection method during the spring and summer rearing. This selection method can be used also for assessment of culture viability. A new express-method of biological material selection for insect cultures establishment has been approbated. It is based on the positive correlation between insect viability parameters and their trophotaxis intensity. It is shown that for establishment of a laboratory culture of gypsy moth it is necessary to obtain the material from populations with the highest chemotaxis intensity. It was experimentally proved that parameters of chemotaxis intensity and insect viability reflect a certain level of population heterozygosity. The higher is the intensity of chemotaxis, the higher is the relative level of population heterozygosity. This fact gives the possibility to determine the level of heterozygosity for artificial insect populations by testing larvae for chemotaxis intensity. This method may be suitable for monitoring of natural populations condition in zones with intensive anthropogenic loading.

A multicopper oxidase-related protein is essential for insect viability, longevity and ovary development.

Typical multicopper oxidases (MCOs) have ten conserved histidines and one conserved cysteine that coordinate four copper atoms. These copper ions are required for oxidase activity. During our studies of insect MCOs, we discovered a gene that we named multicopper oxidase-related protein (MCORP). MCORPs share sequence similarity with MCOs, but lack many of the copper-coordinating residues. We identified MCORP orthologs in many insect species, but not in other invertebrates or vertebrates. We predicted that MCORPs would lack oxidase activity due to the absence of copper-coordinating residues. To test this prediction, we purified recombinant Tribolium castaneum (red flour beetle) MCORP and analyzed its enzymatic activity using a variety of substrates. As expected, no oxidase activity was detected. To study MCORP function in vivo, we analyzed expression profiles of TcMCORP and Anopheles gambiae (African malaria mosquito) MCORP, and assessed RNAi-mediated knockdown phenotypes. We found that both MCORPs are constitutively expressed at a low level in all of the tissues we analyzed. Injection of TcMCORP dsRNA into larvae resulted in 100% mortality prior to adult eclosion, with death occurring mainly during the pharate pupal stage or late pharate adult stage. Injection of TcMCORP dsRNA into pharate pupae resulted in the death of approximately 20% of the treated insects during the pupal to adult transition and a greatly shortened life span for the remaining insects. In addition, knockdown of TcMCORP in females prevented oocyte maturation and, thus, greatly decreased the number of eggs laid. These results indicate that TcMCORP is an essential gene and that its function is required for reproduction. An understanding of the role MCORP plays in insect physiology may help to develop new strategies for controlling insect pests.

Sterilization of Chrysomya putoria (Insecta: Diptera: Calliphoridae) eggs for use in biotherapy.

Large-scale, quality-controlled laboratory production of fly larvae is needed for biotherapy. The objective of this study was to assess the action of glutaraldehyde on the sterilization of Chrysomya putoria eggs by applying pharmaceutical sterility tests. Egg masses with 0.600 g were divided into three parts of 0.200 g, the eggs were separated using sterile distilled water, and the suspensions obtained were mixed with activated 2% glutaraldehyde solution. After 15-min contact, the suspensions were filtered through Whatman filter paper, and the glutaraldehyde residue obtained in the filtrate was neutralized by rinsing with Tryptone Soy Broth. The treated eggs were placed aseptically on Petri dishes containing gauze moistened with sterile saline solution. About 10% of the sterilized mass was transferred to test tubes containing Tryptone Soy Broth and Fluid Thioglycollate Broth. The tubes were incubated, respectively, at 22.5 and 35.0°C for 14 d to verify egg mass sterility. The plates containing the rest of the eggs (90%) were sealed with plastic film and kept in a climatized chamber at 30°C/d, 28°C per night, 60 ± 10% relative humidity, and under a 12-h light period to assess insect viability and survival. Each experiment was carried out in triplicate using a biological class II safety cabinet. No change in color or turgidity was observed with the agent tested, proving the sterility of the product and that there was no trace of contamination. Forty larvae (in three replications) in the periods of 12, 24, and 48 h after sterilization, when transferred to diet, produced larvae, pupae, and total viability similar to the control (larvae without sterilization). However, for the 72- h treatment, larvae and total viability were significantly lower than for the other treatments. There was no significant difference for the pupal stage. The product tested was shown to be efficacious for use as a sterilizer of C. putoria eggs for all the parameters assessed.

Transcriptome analysis of Anopheles stephensi embryo using expressed sequence tags

Germ band retraction (GBR) stage is one of the important stages during insect development. It is associated with an extensive epithelial morphogenesis and may also be pivotal in generation of morphological diversity in insects. Despite its importance, only a handful of studies report the transcriptome repertoire of this stage in insects. Here, we report generation, annotation and analysis of ESTs from the embryonic stage (16-22 h post fertilization) of laboratoryreared Anopheles stephensi mosquitoes. A total of 1002 contigs were obtained upon clustering of 1140 high-quality ESTs, which demonstrates an astonishingly low transcript redundancy (12.1 percent). Putative functions were assigned only to 213 contigs (21 percent), comprising mainly of transcripts encoding protein synthesis machinery. Approximately 78 percent of the transcripts remain uncharacterized, illustrating a lack of sequence information about the genes expressed in the embryonic stages of mosquitoes. This study highlights several novel transcripts, which apart from insect development, may significantly contribute to the essential biological complexity underlying insect viability in adverse environments. Nonetheless, the generated sequence information from this work provides a comprehensive resource for genome annotation, microarray development, phylogenetic analysis and other molecular biology applications in entomology.

Biological features and population density forecasts of the beet webworm Pyrausta sticticalis L. (Lepidoptera, Pyraustidae) in the period of low population density of the pest in Krasnodar Territory

Population dynamics of the beet webworm Pyrausta sticticalis L. was studied in 2003–2005 in Krasnodar Territory (Slavyansk-on-Kuban District) during the period of low population density of the pest. In the period examined, the adult death rate was high, fecundity was low; the low rate of hatchability and high rate of mortality was typical of larvae reared in the laboratory. Analysis of life tables has demonstrated that the observed population density of adults could be explained only by a constant flow of migrants. Low viability of insects from the local population could be explained by the infection with pathogenic microorganisms, including viruses of the Polyhedrosis and Granulosi groups of Baculovirus, and microsporidia, including Nosema sticticalis and Microsporidium sp. Reproduction of the pest can also be influenced by unfavorable weather conditions reducing population density in the subsequent generation. It is demonstrated that the model of the beet webworm population density dynamics based on indices of female fertility, changes in the offspring viability, and the rate of infection with microsporidia is more reliable than models based only on meteorological factors.

Exigências Térmicas de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae)

O desenvolvimento (ovo-adulto) da mosca-branca, Bemisia tabaci (Genn.) biotipo B (=Bemisia argentifolii, Bellows & Perring), foi estudado em condicoes de campo e em câmaras climatizadas, reguladas nas temperaturas constantes de 15, 20, 25, 30 e 35±1oC, usando soja, Glycine max (L.) Merrill, cultivar Msoy 8001, como planta hospedeira. O limite termico inferior de desenvolvimento (Tb) e a constante termica (K) das fases de ovo, ninfa e ciclo biologico (ovo-adulto) foram 11,1oC / 98,8 graus-dia, 6,8oC / 383,8 graus-dia e 8,3oC / 472,6 graus-dia, respectivamente. Nas temperaturas extremas (15oC e 35oC), a viabilidade dos insetos mostrou-se menor. No campo, a emergencia de 70% dos adultos ocorreu depois de terem sido acumulados 413,2 graus-dia. O modelo de graus-dia utilizado mostrou-se adequado para a previsao de ocorrencia de adultos de Bemisia tabaci biotipo B no campo, podendo tambem ser utilizado para determinacao do numero de geracoes nas diferentes regioes do Pais.

CONTROLLED AMBIENT AERATION DURING RICE STORAGE FOR TEMPERATURE AND INSECT CONTROL

Rice (cv. Cypress) was harvested in September 2000 from a farm near Grady, Arkansas, placed in six, 600t(31,000bu) bins [each was filled with ~430 t (21,000 bu)], and dried gently from 18 to 13% moisture content (MC). Threeof the bins were equipped with an aeration control system activated by specific ambient air conditions in three cycles. Threeof the bins were aerated by the onsite, storage manager under his normal regimen. Grain temperatures were recorded at fourlocations within each bin. To monitor insect viability, small cages were filled with approximately 150 g of rice and 20, 1 to2weekold mixed sex adults of one insect species. The species that were tested included the lesser grain borer, Rhyzoperthadominica (Fauvel); the rice weevil, Sitophilus oryzae (L.); and the sawtoothed grain beetle, Oryzaephilus surinamensis (L.).Cages were removed at 5week intervals, and surviving and emerging insects were counted. Grain temperatures weresignificantly reduced through controlled aeration relative to the traditional, manual aeration. In addition, both live insectcounts and total emerged adult insects recovered from the cages were significantly lower (p < 0.05) within the bins treatedwith controlled aeration. The rice weevils were the hardiest of the insects tested, while sawtoothed grain beetles survivedthe least. This work indicates that controlled, ambient aeration can be an effective storage treatment against insects and maybe a useful alternative to chemical controls.

The genetic basis of hybrid inviability in the grasshopper Podisma pedestris

Samples were taken from five sites in a transect across the hybrid zone between two chromosomal races of the grasshopper Podisma pedestris. Crosses were set up between insects from the same population, and between populations spanning the zone, and the early viability of the offspring was measured. Hybrids between pure populations had reduced viability, and the viability of insects from the middle of the zone was still lower, showing that most (∼87 per cent) of the inviability was due to the breakup of coadapated gene complexes. Although the total selection acting was strong (log. fitness reduced by S∼2·5), it was spread over a region wider than the dispersal range (350 m vs. 20 m). Hence, the selection on each locus contributing towards the inviability is weak (∼3 per cent). Many (∼150) independent chromosome segments act cumulatively to produce inviability at this stage in the life history. The implications of these findings for models of divergence are discussed.

A Rapid Separation of Larvae of the Indian Meal Moth1 from Rearing Medium

Laudani (1948) described a variation of the Berlese technique for separation of the larvae of the carpet beetle, Anthrenus scrophulariae (L.), from diet medium based on the negative phototaxis of the larvae. Because our biochemical and physiological investigations of the Indian meal moth, Plodia interpunctella (Hübner), often require many larvae, we attempted to modify Laudani's technique by utilizing the negative thermotaxic and phototaxic responses of Indian meal moth larvae. Larval development, adult emergence, egg production, and egg viability of insects removed by this method were not adversely affected.

A preliminary report on genetic variability in the German cockroach, Blattella germanica.

A search for mutants of Blattella germanica (L.) has led to the discovery of numerous heritable traits, 9 of which are described in this paper. These include 4 which affect body structures, 1 eye-color mutant, 1 resulting in loss of ocelli, and 3 which affect body color. Data concerning the patterns of inheritance and tests for linkage are presented. The work indicates that genes controlling color and color pattern will probably be the most useful markers owing to their frequency and the viability of insects with these traits. In addition, the morphology of 2 structural mutants is highly suggestive of the presence of genetic mechanisms leading to the appearance of apparently primitive body structures.