Dead Insects Research Articles

In-vivo biomagnetic characterisation of the American cockroach

We present a quantitative method, utilising a highly sensitive quantum sensor, that extends applicability of magnetorelaxometry to biological samples at physiological temperature. The observed magnetic fields allow for non-invasive determination of physical properties of magnetic materials and their surrounding environment inside the specimen. The method is applied to American cockroaches and reveals magnetic deposits with strikingly different behaviour in alive and dead insects. We discuss consequences of this finding to cockroach magneto-reception. To our knowledge, this work represents the first characterisation of the magnetisation dynamics in live insects and helps to connect results from behavioural experiments on insects in magnetic fields with characterisation of magnetic materials in their corpses.

STEREO AND SCANNING ELECTRON MICROSCOPY CHARACTERISTICS OF POULTRY BREEDING BEETLE (Alphitobius diaperinus) – A FILAMENTOUS TOXIGENIC FUNGI CARRIER

This study isolated Alphitobius diaperinus (live and dead) insects from shed’s aviary bed to investigate their fungi spores distribution (that affects chicken health and meat production) and their accumulation sites (dorsal & ventral) characteristics by different microscopies (stereo and scanning electron). Despite live beetles being the main fungi spore carriers, the dead ones had far more spores attached on their body exoskeleton thereby being a focus of infection. That was due to the anatomical sites favoring spores trapping effect, together with beetles’ different moisture content. Regarding the spores distribution and so the hyphae presence & mycelia concentration on dead A. diaperinus, they were mainly detected at the (a) elytra, elytral suture and pronotum (on the dorsal side). Despite that, the highest spores/mycelia concentration was at the mouthparts, prosternum and legs (femur & tarsus) (on the ventral side). Indeed the beetle’s ventral anatomical microscopic structures (mouthparts & legs) sheltered the highest fungi spores concentration and colonies proliferation. Thus dead beetle colonies growth lead to spore multiplication, their dissemination throughout the aviary bed environment and so their contact to chicken feet and body, leading to discomfort and diseases development / mycotoxicosis. The filamentous fungi were most detected from the Aspergillus and Penicillium genera. Therefore dead beetles should be removed from aviary (at each 45 breeding cycle) to reduce contamination. They represent rich substrates for fungi development with possibility of toxin formation, apart from the chicken diseases exposure due to their insects eating habits.

Biodiversity of <i>Bacillus thuringiensis</i> Strains and Their <i>Cry</i> Genes in Ecosystems of Kyrgyzstan

The present study aims to isolate the unknown and known serotypes of Bacilllus thuringiensis (Bt) from natural objects in Kyrgyzstan. A total of 83 Bt strains were isolated from natural substrates, of which 30% were taken from the soil and litter samples, 69.7% from dead insects and about 0.3% from slugs. Serological examination revealed that such subspecies as var. thuringiensis (H-1), var. alesti (H-3), var. sotto (H-4a4b) and var. entomocidus (H-6) predominated in the upper horizon of soils in all climatic zones. In the dead insects such species as subsp. thuringiensis, subsp. galleria, subsp. sotto, subsp. kurstaki, subsp. Aizawai and subsp. Entomocidus dominated. A set of Bt strains isolated from insects and soil samples, selected from different ecosystems in Kyrgyzstan was molecular taxonomically characterized using the pycA gene as marker for phylogenetic reconstruction. Within the Bacillus cereus sensu lato species complex, all Kyrgyz isolates were shown to belong to the B. cereus subspecies thuringiensis. Most isolates were assigned to the lineage Bt tolworthi, with two isolates each belonging to the lineages Bt kurstaki and Bt sotto. A high degree of cry gene diversity was demonstrated in the set of Bt isolates, with several gene copies simultaneously present in a single strain; a particularly conspicuous trait was the frequent combination of Lepidopteran-specific cryI with Dipteran-specific cryIV genes in the same Bt isolate.

Evaluation of some essential oils against maize weevil Sitophilus zeamais (L.)

Maize is the most important cereal in Africa, and in Ethiopia, it is the second widely grown cereal. Post harvest losses due to the maize weevil Sitophilus zeamais is an important constraint, with grain losses ranging from 20–90%. This study evaluates the efficacy of essential oils against this weevil as an alternative to pesticides. Adult S. zeamais were bred in jars in the laboratory at 60–65% RH and 27±2°C. Five treatments viz., eucalyptuss, citronella grass and lemon grass essential oils each at 2.5, 5.0, 7.5 and 10.0/were poured into petri dishes containing diatomaceous earth (DE). Ethiolathion (Malathion 5%) and 95% ethanol were used as a standard check and as control, respectively. Ten pairs of adults S. zeamais were introduced into each treatment containing maize grains. Treatments were arranged in a complete randomized design (CRD) with four replications. The numbers of dead insects in each petri dish were counted at 24h, 48h, 72h, 96h, and 120h to estimate mortality rate. Grain weight losses were determined after seven days. The results revealed significant differences among treatments effects in the rate of mortality. All essential oil significantly affected weevil mortality compared to untreated control. The results showed that grain weight loss can be 18–60% after seven day due to weevil damage.

Diversity and distribution of lepidopteran-specific toxin genes in Bacillus thuringiensis strains from Argentina

A total of 268 Bacillus thuringiensis strains obtained from different sources of Argentina were analyzed to determine the diversity and distribution of the cry1, cry2, cry8, cry9 and vip3A genes encoding for lepidopteran-specific insecticidal proteins. Twin strains were excluded. Ten different profiles were detected among the 80 selected B. thuringiensis strains. Two of these profiles (cry1Aa, cry1Ac, cry1Ia, cry2Aa, cry2Ab and vip3Aa (35/80), and cry1Aa, cry1Ab, cry1Ac, cry1Ia, cry2Aa, cry2Ab and vip3Aa (25/80)) pooled 75% of the strains. The existence of this low diversity is rare, since in most of the studied collections a great diversity of insecticidal toxin gene profiles has been described. In addition, the most frequently detected profile was also most frequently derived from soil (70%), stored product dust (59%) and spider webs (50%). In contrast, the cry1Aa, cry1Ab, cry1Ac, cry1Ia, cry2Aa, cry2Ab and vip3Aa profiles were mainly detected in strains isolated from leaves (40%) and dead insect larvae (50%). Six of the identified insecticidal toxin gene profiles were discovered in strains isolated from stored product dust and leaves indicating higher diversity of profiles in these kinds of sources than in others. Some strains with high insecticidal activity against Epinotia aporema (Lepidoptera) larvae were identified, which is important to explore future microbial strategies for the control of this crop pest in the region.

Characterization of Cry toxins from autochthonous Bacillus thuringiensis isolates from Mexico

BackgroundChemical pesticides, widely used in agriculture and vector-borne disease control, have shown toxic effects on the environment and the people in contact with them. Bacillus thuringiensis is a widely used bacterium for alternative and safer control of insect pests. Its toxins are specific for insects but innocuous for mammals and may be used as powerful adjuvants when applied with vaccines. The objective of this work was to characterize some autochthonous B. thuringiensis strains, which could be used for the control of a local pest (Diatraea considerata Heinrich) that affects sugar cane crops in Sinaloa, Mexico. Also, to evaluate these strains as a source of Cry toxins, which may be used in the future as adjuvants for some vaccines. MethodsEight strains from field-collected dead insects were isolated. These were microbiologically identified as B. thuringiensis and confirmed by amplification and sequencing of 16S rDNA. Bioassays were performed to evaluate their pathogenicity against D. considerata, and Cry toxins were identified by proteomic analyses. ResultsAn increased mortality among larvae infected with strain Bt-D was observed, and its toxin was identified as Cry1Ac. ConclusionsThe observed data showed that the selected strain was pathogenic to D. considerata and seemed to produce Cry1Ac protein, which has been reported as an adjuvant in different types of immunization.

English

The use of natural products with insecticidal action is a control method compatible with integrated pest management, since it reduces the impacts caused to human health and the environment. This study aimed to assess the effect of Azadirachta indica A. Juss. (Meliaceae) leaf and seed aqueous extracts, on citrus blackfly (Aleurocanthus woglumi Ashby). Citrus x latifolia Tanaka ex Q. Jiménez leaves infested with blackfly nymphs were immersed for five seconds in different A. indica leaf and seed extract concentrations (1.0, 2.5, 5.0 and 10 w/v). Distillate water was used as control. The assessments were performed at 3, 6 and 9 days after leaf immersion, by counting dead insect number. The A. indica leaf and seed aqueous extracts were efficient in the mortality of A. woglumi nymphs, representing an alternative method to control this pest.   Key words: Insecticidal activity, Azadirachta indica extracts, Aleurocanthus woglumi Ashby

Translocation of Bacillus thuringiensis in Phaseolus vulgaris tissues and vertical transmission in Arabidopsis thaliana.

To demonstrate the ability of Bacillus thuringiensis to penetrate as spore-crystal complex to the internal tissues of bean plants, and keep its insecticidal activity. To test the vertical transmission of the spore-crystal complex in Arabidopsis thaliana. The experimental strain was transformed with the pMUTIN-gfp plasmid which labelled the spores of B. thuringiensis HD-73 with the GFP protein. Once the rhizosphere of the bean plants was inoculated with the labelled strain, the bacterium was recovered from leaves, stems, and petioles. Furthermore, toxicity of treated plants was significantly higher than control plants when bio-assayed on cabbage looper larvae. The labelled strain was recovered from the dead insects. When the rhizosphere of A. thaliana plants was inoculated with the labelled strain, mature seeds from these plants were surface-sterilized and grown under invitro conditions. The labelled strain was recovered from the seedlings. We showed that B. thuringiensis subsp. kurstaki (HD-73) in the rhizosphere can translocate to upper tissues of bean plants, and keep its insecticidal activity. Transmission of the labelled B. thuringiensis strain passed to the next generation of A. thaliana. The role of B. thuringiensis as a potential facultative endophyte bacterium and the possible biotechnological repercussions are discussed.

Effect of the Presence of Live or Dead Insects on Subsequent Captures of Six Stored-Product Beetle Species: The Relative Species Matters.

In trapping programs prior capture of individuals of the same or different species may influence subsequent attractiveness of the trap. To evaluate this process with stored-product insects, the effect of the presence of dead or alive adults in traps on the behavioral responses of six stored-product insect species, Tribolium confusum Jacquelin du Val, T. castaneum (Herbst) (Coleoptera: Tenebrionidae), Sitophilus oryzae (L.), S. granarius (L.) (Coleoptera: Curculionidae), Oryzaephilus surinamensis (L.) and O. mercator (Fauvel) (Coleoptera: Silvanidae), was studied in choice tests under laboratory conditions. Two series of tests were carried out. In the first series, the choice was between either alive or dead adults of same species and blank (no adults). Overall, dead adults had the strongest influence, increasing the response of S. oryzae, S. granarius, O. surinamensis, and O. mercator and decreasing the response of the two Tribolium species. Presence of alive adults generally did not result in a response different from blank, except for T. castaneum and O. surinamensis that had a reduced response. In the second series of tests, the choice was between alive or dead individuals of the species vs. alive or dead individuals of its relative cogeneric species. For choices between alive individuals, S. oryzae, S. granarius, and O. surinamensis showed a preference for alive individuals of the same species vs. the cogeneric species, and for all the other species there was no preference. For choices between dead individuals, T. castaneum exhibited a preference for individuals of the same species, while S. oryzae, S. granarius, and O. mercator showed a preference for individuals of the cogeneric species, and all other combinations did exhibit a preference. Our results suggest that traps containing alive and dead individuals of the same and other species can seriously affect the response and capture of additional insects.

On the autorotation of animal wings.

Botanical samaras spin about their centre of mass and create vertical aerodynamic forces which slow their rate of descent. Descending autorotation of animal wings, however, has never been documented. We report here that isolated wings from Anna's hummingbirds, and also from 10 species of insects, can stably autorotate and achieve descent speeds and aerodynamic performance comparable to those of samaras. A hummingbird wing loaded at its base with the equivalent of 50% of the bird's body mass descended only twice as fast as an unloaded wing, and rotated at frequencies similar to those of the wings in flapping flight. We found that even entire dead insects could stably autorotate depending on their wing postures. Feather removal trials showed no effect on descent velocity when the secondary feathers were removed from hummingbird wings. By contrast, partial removal of wing primaries substantially improved performance, except when only the outer primary was present. A scaling law for the aerodynamic performance of autorotating wings is well supported if the wing aspect ratio and the relative position of the spinning axis from the wing base are included. Autorotation is a useful and practical method that can be used to explore the aerodynamics of wing design.

Effect of Aqueous Extract of Protium heptaphyllum (Burseraceae) on Lutzomyia longipalpis (Diptera: Psychodidae), a Proven Vector of Visceral Leishmaniasis in Brazil

Objective: To evaluate the toxicity of aqueous extract of Protium heptaphyllum on Lutzomyia longipalpis a proven vector of visceral leishmaniasis (VL). Methods: Aqueous extract of the leaves of P. heptaphyllum were prepared at 0.25, 0.10,0.05 and 0.025 mg/mL concentrations, and 100 μL was applied to adults of Lu. longipalpis (n=20). Controls included 20 adults that were treated with 100 μL distilled water (negative control) and 20 adults that were treated with 100 μL alpha-cypermethrin at 196 µg/mL concentration (positive control). The percentage of dead insects in each group was observed at 1, 2, 4, 8, 12, 24, 48 and 72h after application. Results: The mortality rate of Lu. longipalpis after 2h of exposure to the extract at a concentration of 0.1 mg/mL was 52%, behaving similarly to the positive controls (cypermethrin), and the extract at a concentration of 0.25 mg/ml was able to kill 56% of insects within the first hour of exposure. After 72h, the aqueous extract of P. heptaphyllum showed a mortality rate of about 81% and 83%, at concentrations of 0.1 and 0.25 mg/mL, respectively. Conclusion: The extract of P. heptaphyllum contains terpenes, a molecule with recognized toxicity in insects, and which may be responsible for killing the phlebotomines. These results demonstrate the potential use of this extract in the control of this vector

Field evaluation of the long-lasting treated storage bag, deltamethrin incorporated, (ZeroFly® Storage Bag) as a barrier to insect pest infestation

The deltamethrin incorporated polypropylene (PP) bag, ZeroFly® Storage Bag, is a new technology to reduce postharvest losses caused by stored-product insect pests. Maize was pre-fumigated and used for the following treatments: ZeroFly bags filled with untreated maize, PP bags filled with maize treated with Betallic Super (80 g pirimiphos-methyl and 15 g permethrin per liter as an emulsifiable concentrate (EC)), and PP bags filled with untreated maize (control). The experiment was conducted from February–August 2015, at four sites in different locations of the Middle Belt of Ghana. Moisture content (MC), number of live and dead insects, insect damaged kernels (IDK) and maize weight loss data were collected monthly. ZeroFly bags and Betallic treatment significantly reduced insect damage compared to the control treatment. ZeroFly bags were able to keep IDK levels below 5% for 4 months, but the levels increased to 5.2 and 10.2% by 5 and 6 months of storage, respectively. In the control, IDK increased significantly over time and reached 32% after 6 months. The ZeroFly bag was effective against Sitophilus, Tribolium and Cryptolestes species for 4 months. Mean weight loss of ≤3.68% was recorded in ZeroFly bags during 6 months of storage whereas 11.88% weight loss occurred in the PP bags by 6 months of storage. Based on our results, ZeroFly bags were found to have potential for use in the reduction of postharvest grain losses in bagged grains. Maize may still have been infested during bagging hence ZeroFly bags were effective for storage for only 4 months. However, greater benefits of using ZeroFly bags are realized if insect-free grains or legumes are stored in bags.

Watch your step: insect mortality on hiking trails

Abstract Hiking may have a negative effect on vertebrates, but the impact on insects is unknown. Large‐scale hiking may lead to habitat degradation, the introduction of alien species and the killing of insects occurring in places visited by people. The aim of this study was to determine the influence of hiking on the mortality of insects. Randomly selected hiking trails in the western Carpathians (southern Poland) were surveyed and dead insects lying on the trails were collected. To compare the composition of ground‐dwelling insects killed on trails, insects from free‐living populations were sampled with ground pitfall traps. The species abundance of insects killed on trails and those caught in traps differed significantly. Apart from common species, rare and legally protected insects were also found on the trails. Trail mortality peaked in July along with increasing hiking activity. Body size did not affect mortality, at either the species or individual levels. Species mobility influenced mortality, with less mobile species being more vulnerable to trampling. Trampled insects remained on the ground for a maximum of 72 h, although 50% disappeared within 24 h. Our results indicate that trail‐killing is, to some degree, a random process and that hiking can influence insects by the elimination of individuals. Given the total length of hiking trails in Poland (76 400 km), and the significant human impact on natural areas resulting therefrom, hiking may be having a negative influence on insect populations.

Spathodea campanulata (Bignoniaceae) extracts bioactivity against Sitophilus zeamais (Coleoptera: Curculionidae)

The insect attack is one of the main factors responsible for the loss of corn grain stored after harvest, thus sustainable strategies such as natural extracts can be used as cheap methods of control. This study evaluated the effects caused by Spathodea campanulata nectar extracts on the maize weevil Sitophilus zeamais to the preference test and mortality was used completely randomized design with 10 replications and treatments solutions of 0, 5, 10, 30 to 50% nectar under study. He noted that the preference index was lower in the first 3 hours of evaluation and the highest concentration of extract (50%), resulting in a possible repellent effect, but with the potential loss in subsequent evaluations. Already mortality was increased from the concentration of 30%, but the number of dead insects was low, indicating low efficiency. However, the percentage of perforated grains was reduced at the highest concentration and decreasing interfering insect feeding.

Label-Free Differential Proteomics and Quantification of Exoenzymes from Isolates of the Entomopathogenic Fungus Beauveria bassiana.

Beauveria bassiana is an entomopathogenic fungus that grows both in vivo and in vitro. In vivo it can colonize live insect hosts, and tissue digestion occurs by secreted hydrolytic exoenzymes. It can also colonize dead insect tissue provided this is free from competing microorganisms. Depending on whether the host is alive or dead the expression (quality/quantity) of the exoenzymes may vary. We have grown several isolates of B. bassiana in shaking flasks for 120 h at 25 °C in order to evaluate the maximal exoenzyme production using two diet regimes. As sole carbon, nitrogen, and phosphate sources we used 1% shrimp chitin and either 0.5% w/v of dead intact American cockroach (Periplaneta americana) or their isolated cuticles. This is the first report of a differential proteomics of B. bassiana exoenzymes performed by label-free nano-LC MS/MS. Total proteolytic enzyme activity was mainly due to Pr1A or Pr1B depending on the isolate and the diet regime. The most differentially secreted enzymes were: the cuticle-degrading subtilisin Pr1A, GH13 alpha-glycosidase, glucan endo-1,3-beta-glucosidase, subtilisin-like proteinase Spm1, lipase 1, beta-1,3 exoglucanase, and endo-1,3-beta-glucosidase. Among the B. bassiana isolates analyzed, Bb 678 and Bb BG were the most active in Pr1A secretion.

Look What Crawled Up

Throughout time and around the world insects have been used medicinally in multiple cultures. Termites in Ayurveda have been used to treat conditions such as ulcers, anemia and rheumatic diseases. Bee venom, also called Melittin, has been proposed to treat inflammation in rheumatoid arthritis and multiple sclerosis. Maggot therapy has been shown to be effective in wound cleaning. Wasp venom has been studied to help kill cancer cells through certain pathways. Extracts from the silkworm have been used by many healers in Asia to treat a broad variety of symptoms, from flatulence to seizure disorders. Although some examples listed may have been proven to be somewhat effective, a vast array of research is still required to determine the validity of such methods in the field of medical entomology. We present a 50-year-old Hispanic female with no significant past medical history who presented for a screening colonoscopy. During the procedure a bead like object was noted. As the colonoscope was advanced a vast amount of these object were encountered. On closer inspection it was confirmed that these were dead insects that were occupying her colon from the cecum to the ascending colon. Upon further questioning, the patient admitted to the ingestion of “gorgojos chinos.” Gorgojos Chinos is a type of beetle better known as the flour bug or the Chinese weevil from the cucolionoioidea superfamily. This appears to be a growing tradition in the Hispanic population. It is believed that once these insects die in the stomach they secret an enzyme that can strengthen the body's defenses against various diseases ranging from AIDS to diabetes. Despite anecdotal information on various online forums, there is limited if any scientific literature presented on gorgojos chinos and its health claims. To our knowledge, we report the first case of gorgojos chinos found incidentally during colonoscopy.Figure 1Figure 2Figure 3

Mechanisms of mortality in Culicoides biting midges due to Haemoproteus infection.

We examined the effects of Haemoproteus infection on the survival and pathology caused in the biting midges. Forty-six females of Culicoides impunctatus were exposed experimentally by allowing them to feed on a naturally infected red-backed shrike infected with Haemoproteus lanii (lineage hRB1, gametocytaemia 5·2%). Seventeen females were fed on an uninfected bird (controls). Dead insects were collected, counted and used for dissection, histological examination and polymerase chain reaction-based testing. Parasites were present in all experimentally infected biting midges, but absent from control insects. Survivorship differed significantly between the control and infected groups. Twelve hours post-exposure (PE), 45 (98%) experimentally infected midges were dead, but all control midges remained alive, and many of them survived until 7 day PE. The migrating ookinetes of H. lanii overfilled midgut, markedly damaged the midgut wall, entered the haemocoel and overfilled the abdomen and thorax of exposed biting midges. Massive infection by migrating ookinetes led to damage of abdomen and thorax of biting midges. The parasites often present in large clumps in the haemocoel in abdomen and thorax, leading to the interruption of the haemolymph circulation. These are the main reasons for rapid death of biting midges after feeding on high-intensity infections of Haemoproteus parasites.

Occurrence of entomopathogenic fungi on insect pests of stored wheat and maize in Central and South Anatolia in Turkey

Naturally occurring fungal pathogens of stored-grain insect pests were identified and quantified using different insect sampling techniques in wheat and maize storage facilities in Central and South Anatolia in Turkey. Storage facilities were sampled by probing, trapping and visual inspection in five cities (Sanliurfa, Kahramanmaras, Adana, Mersin and Konya) from June to November 2013. Entomopathogenic fungi recovered from dead insects were identified to species level by sequencing the ITS1-5.8S-ITS2 region of the genomic DNA. Of the three species isolated, the majority were Beauveria bassiana (97 isolates), followed by Purpureocillium lilacinum (20 isolates). The third species, Beauveria varroae (9 isolates), is the first record on stored-product pest insects. Thirty-five isolates were from Tribolium spp., 29 from Sitophilus spp., 24 from Cryptolestes ferrugineus, 22 from Rhyzopertha dominica, 8 from Oryzaephilus surinamensis, 4 from Trogoderma granarium, 3 from Latheticus oryzae and 1 from a species of Cryptophagidae. The fungal infection of stored-grain pests did not vary significantly according to the time of sampling. A higher frequency of occurrence was recorded for Adana than the other cities and for Tribolium species than the other hosts. Grain samples taken by probing resulted in a higher frequency of fungal infection, but commodity type did not have a significant effect. The results demonstrated that (1) entomopathogenic fungi occurred at a low frequency, and (2) location, together with sampling technique, can affect their recovery. Further exploration of this ecosystem could yield important information for improving their use for management of stored-grain pests.

Salvia officinalis essential oil in bean weevil control

ABSTRACT Bean weevil [Acanthoscelides obtectus Say (Coleoptera: Bruchidae)] is considered the main storage pest of the bean crop. Its control is performed mainly by chemical treatment, which has potential to cause resistance in pests, as well as environmental contamination. This study aimed at evaluating the insecticidal and repellent effect of Salvia officinalis L. essential oil against bean weevil. The doses used for the insecticidal test were: 0 L t-1, 0.5 L t-1, 1.0 L t-1, 1.5 L t-1, 2.5 L t-1 and 5.0 L t-1 of bean grains. For the mortality test, the experimental design was completely randomized, in a 6 × 7 (dose × time) factorial scheme, with five replications. The number of dead insects was counted at 2, 6, 12, 24, 48, 72 and 96 h after the insect introduction. The repellency test was conducted in arenas, under a completely randomized design, using the same doses applied to evaluate the insecticidal effect. Counts were performed 24 h after the introduction of insects. The insecticidal effect of the S. officinalis essential oil on A. obtectus resulted in mortality rates higher than 95 %, after 6 h of insect introduction, for all doses tested. Repellency effect was also detected for all doses tested.

Singing with the Bees: Abeille, an exhibition

Singing with the Bees: Abeille, an exhibition