Red Flour Beetle Tribolium Castaneum Research Articles

Towards reconstructing the dipteran demise of an ancient essential gene: E3 ubiquitin ligase Murine double minute.

Genome studies have uncovered many examples of essential gene loss, raising the question of how ancient genes transition from essentiality to dispensability. We explored this process for the deeply conserved E3 ubiquitin ligase Murinedouble minute (Mdm), which is lacking in Drosophila despite the conservation of its main regulatory target, the cellular stress response gene p53. Conducting gene expression and knockdown experiments in the red flour beetle Tribolium castaneum, we found evidence that Mdm has remained essential in insects where it is present. Using bioinformatics approaches, we confirm the absence of the Mdm gene family in Drosophila, mapping its loss to the stem lineage of schizophoran Diptera and Pipunculidae (big-headed flies), about 95-85 million years ago. Intriguingly, this gene loss event was preceded by the de novo origin of the gene Companion of reaper (Corp), a novel p53 regulatory factor that is characterized by functional similarities to vertebrate Mdm2 despite lacking E3 ubiquitin ligase protein domains. Speaking against a 1:1 compensatory gene gain/loss scenario, however, we found that hoverflies (Syrphidae) and pointed-wing flies (Lonchopteridae) possess both Mdm and Corp. This implies that the two p53 regulators have been coexisting for ~ 150 million years in select dipteran clades and for at least 50 million years in the lineage to Schizophora and Pipunculidae. Given these extensive time spans of Mdm/Corp coexistence, we speculate that the loss of Mdm in the lineage to Drosophila involved further acquisitions of compensatory gene activities besides the emergence of Corp. Combined with the previously noted reduction of an ancestral P53 contact domain in the Mdm homologs of crustaceans and insects, we conclude that the loss of the ancient Mdm gene family in flies was the outcome of incremental functional regression over long macroevolutionary time scales.

Repellency of Ferulago angulata (Schlecht.) Boiss essential oil on two major stored-product insect pests without effect on wheat germination

There has been an increasing demand among agricultural researchers and producers for bio-insecticides due to the threats of the related chemicals leading to human health problems, environmental contamination, pest resistance, and secondary pest outbreaks. In this regard, the repellent effects of the essential oil extracted from Ferulago angulata (Schlecht.) Boiss as a well-known medicinal plant were measured against the red flour beetle (Tribolium castaneum (Herbst)) and lesser grain borer (Rhyzopertha dominica (F.)) using the three different techniques of filter paper, leaky glass, and olfactometry. The experiments were conducted at the concentrations of 30, 52, 93, 165, and 300 ppm under controllable conditions. The maximum Percent Repellency (PR) rates of the essential oil at the concentration of 300 ppm were found to be 59.01, 54.12, and 43.21% for T. castaneum and 48.84, 50.52, and 42.73% for R. dominica based on the mentioned methods, respectively. By enhancing the essential oil concentrations and exposure times, the PR rates increased. Furthermore, the essential oil effects of F. angulata on wheat germination were evaluated and no decreases in the germination of the treated wheat seeds were found at the tested concentrations. According to the results of the present study, the essential oil of F. angulata could be used for reducing T. castaneum and R. dominica populations.

Insecticidal Activity of Artemisia vulgaris Essential Oil and Transcriptome Analysis of Tribolium castaneum in Response to Oil Exposure

Red flour beetle (Tribolium castaneum) is one of the most destructive pests of stored cereals worldwide. The essential oil (EO) of Artemisia vulgaris (mugwort) is known to be a strong toxicant that inhibits the growth, development, and reproduction of T. castaneum. However, the molecular mechanisms underlying the toxic effects of A. vulgaris EO on T. castaneum remain unclear. Here, two detoxifying enzymes, carboxylesterase (CarEs) and cytochrome oxidase P450 (CYPs), were dramatically increased in red flour beetle larvae when they were exposed to A. vulgaris EO. Further, 758 genes were differentially expressed between EO treated and control samples. Based on Gene Ontology (GO) analysis, numerous differentially expressed genes (DEGs) were enriched for terms related to the regulation of biological processes, response to stimulus, and antigen processing and presentation. Our results indicated that A. vulgaris EO disturbed the antioxidant activity in larvae and partially inhibited serine protease (SP), cathepsin (CAT), and lipase signaling pathways, thus disrupting larval development and reproduction as well as down-regulating the stress response. Moreover, these DEGs showed that A. vulgaris indirectly affected the development and reproduction of beetles by inducing the expression of genes encoding copper-zinc-superoxide dismutase (CuZnSOD), heme peroxidase (HPX), antioxidant enzymes, and transcription factors. Moreover, the majority of DEGs were mapped to the drug metabolism pathway in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Notably, the following genes were detected: 6 odorant binding proteins (OBPs), 5 chemosensory proteins (CSPs), 14 CYPs, 3 esterases (ESTs), 5 glutathione S-transferases (GSTs), 6 UDP-glucuronosyltransferases (UGTs), and 2 multidrug resistance proteins (MRPs), of which 8 CYPs, 2 ESTs, 2 GSTs, and 3 UGTs were up-regulated dramatically after exposure to A. vulgaris EO. The residual DEGs were significantly down-regulated in EO exposed larvae, implying that partial compensation of metabolism detoxification existed in treated beetles. Furthermore, A. vulgaris EO induced overexpression of OBP/CYP, and RNAi against these genes significantly increased mortality of larvae exposed to EO, providing further evidence for the involvement of OBP/CYP in EO metabolic detoxification in T. castaneum. Our results provide an overview of the transcriptomic changes in T. castaneum in response to A. vulgaris EO.

Effect of RNAi‐mediated silencing of two Knickkopf family genes (LmKnk2 and LmKnk3) on cuticle formation and insecticide susceptibility in Locusta migratoria

Knickkopf (Knk) proteins play crucial roles in the formation of insect cuticle. Recent studies in the holometabolous insect red flour beetle (Tribolium castaneum) have shown that three Knk genes encoding TcKnk, TcKnk2 and TcKnk3 play different but essential roles at different developmental stages and in different tissues. However, the functions of Knk genes had not been fully explored in hemimetabolous insects such as the migratory locust Locusta migratoria. We identified three transcripts of LmKnk-like genes LmKnk2 and LmKnk3 with the full-length cDNA sequences, which were named as LmKnk2, LmKnk3-FL and LmKnk3-5'. These three transcripts were highly expressed before molting and mainly expressed in the integument. Among these genes, silencing only LmKnk3-5' by RNA interference (RNAi) caused molting defects and high mortality of the locusts. Injection of dsLmKnk3-5' dramatically decreased chitin content, but did not affect cuticle laminar ultra-structures in the integument. After the knockdown of LmKnk3-5' transcript, lipid deposition on the cuticle surface was impeded, and locusts exhibited increased susceptibility to each of four insecticides in three different classes. However, no visible phenotypic changes were observed after LmKnk2 or LmKnk3-FL was silenced by RNAi. We demonstrate that LmKnk3-5' is essential for cuticle formation in L. migratoria. This contrasts the findings that the cognate protein in T. castaneum TcKnk3-5' is dispensable for cuticle formation and survival. Hence, we provide some evidence that the function of Knk-type proteins may be species-specific. We therefore think that LmKnk3-5' may be a good target for the application of RNAi-based technologies for species-specific insect pest management. © 2020 Society of Chemical Industry.

A new neuropeptide insect parathyroid hormone iPTH in the red flour beetle Tribolium castaneum.

In the postgenomics era, comparative genomics have advanced the understanding of evolutionary processes of neuropeptidergic signaling systems. The evolutionary origin of many neuropeptidergic signaling systems can be traced date back to early metazoan evolution based on the conserved sequences. Insect parathyroid hormone receptor (iPTHR) was previously described as an ortholog of vertebrate PTHR that has a well-known function in controlling bone remodeling. However, there was no sequence homologous to PTH sequence in insect genomes, leaving the iPTHR as an orphan receptor. Here, we identified the authentic ligand insect PTH (iPTH) for the iPTHR. The taxonomic distribution of iPTHR, which is lacking in Diptera and Lepidoptera, provided a lead for identifying the authentic ligand. We found that a previously described orphan ligand known as PXXXamide (where X is any amino acid) described in the cuttlefish Sepia officinalis has a similar taxonomic distribution pattern as iPTHR. Tests of this peptide, iPTH, in functional reporter assays confirmed the interaction of the ligand-receptor pair. Study of a model beetle, Tribolium castaneum, was used to investigate the function of the iPTH signaling system by RNA interference followed by RNA sequencing and phenotyping. The results suggested that the iPTH system is likely involved in the regulation of cuticle formation that culminates with a phenotype of defects in wing exoskeleton maturation at the time of adult eclosion. Moreover, RNAi of iPTHRs also led to significant reductions in egg numbers and hatching rates after parental RNAi.

Disinfestation of red flour beetle (Tribolium castaneum) present in almonds (Prunus dulcis) using microwave heating and evaluation of quality and shelf life of almonds

Almonds (Prunus dulcis) are one of the high-value nuts facing insect pest infestation predicaments during post-harvest operations and subsequent storage. The red flour beetle (Tribolium castaneum) (Coleoptera: Tenebrionidae) is an economically important and notorious insect pest that globally infest almonds thereby resulting in high storage losses. Currently, the fumigants (hydrogen phosphide and propylene oxide) commonly used during almond storage pose a health hazard to the applicator and consumer as well as the environment. Other disadvantages of chemical methods include chemical residue, high exposure time (2–4 days), pest resistance, the demise of beneficial insects and incomplete disinfestation of the egg stage of the target pest. Among other physical disinfestation methods, the use of microwave as a disinfestation technique offer advantages of less processing time, lower energy consumption, clean technology, and no residues. Therefore to test the efficacy of microwave in pest control of stored almonds, we exposed life stages of T. castaneum to microwave irradiation at different power levels (120–600 W) and durations (30–90 s). Hundred percent mortality of all selected life stages was achieved at 480 and 600 W when infested almonds exposed for 90 and 60 s respectively. The quality attributes of treated almonds such as color difference, water activity, hardness, peroxide value, free fatty acid, and iodine value were measured and found to be acceptable. The fatty acid composition and sensory analysis demonstrated no significant difference (p > 0.05) in control and microwave treated almonds. The storage studies revealed that microwave treated almonds were free from infestation and rancidity for up to 12 months, whereas untreated almonds were spoiled within 3 months.

Comparative Mortality and Adaptation of a Smurf Assay in two Species of Tenebrionid Beetles Exposed to Bacillus thuringiensis.

Bacillus thuringiensis is a spore-forming bacterium which infects insect larvae naturally via the oral route. Its virulence factors interact with the epithelium of the digestive tract of insect larvae, disrupting its function and eventually leading to the death of susceptible hosts. The most cited B. thuringiensis killing mechanism is the extensive damage caused to the insect midgut, leading to its leakage. The mortality caused by B. thuringiensis has been shown to vary between serovars and isolates, as well as between host life stages. Moreover, whether susceptibility to B. thuringiensis-induced gut leakage is generalized to all host species and whether there is individual variation within species is unclear. In this study, we adapted a non-invasive “Smurf” assay from Drosophila melanogaster to two species of tenebrionid beetles: The mealworm beetle Tenebrio molitor and the red flour beetle Tribolium castaneum, during exposure to B. thuringiensis. We highlight a differential mortality between two age/size classes of T. molitor larvae, as well as different killing dynamics between B. thuringiensis var. tenebrionis and var. tolworthi in T. castaneum. The Smurf assay did not reveal a high occurrence of extensive gut disintegration in both host species upon ingestion during B. thuringiensis exposure.

The Cytotoxic Effect of Genistein, a Soybean Isoflavone, against Cultured Tribolium Cells.

The red flour beetle Tribolium castaneum is a known pest of various grains and stored-products such as wheat flours; however, T. castaneum feeds on and infests soybean and soy products. For more than 60 years, soy flour has been suggested to be unstable food for Tribolium spp. because it causes larval development failure. However, it remains unknown whether soy flour affects adult beetles. The objective of the present study was to examine the effects of soy flour and its related isoflavones against T. castaneum using an artificial dietary intake assay. Beetles were fed gypsum (a non-digestible compound) mixed with either water (control) or soy flour. Significantly fewer beetles survived after being fed the soy flour treatment. Although the soy isoflavone genistein, a defensive agent and secondary metabolite, decreased the T. castaneum adult survival, it required a long time to have a lethal effect. Therefore, the cytotoxic effects of soy flour, i.e., the rapid biological responses following isoflavone addition, were also examined using a cultured cell line derived from T. castaneum. Both genistin and genistein significantly affected the survival of the cultured cells, although genistein had a stronger lethal effect. This study demonstrated the toxicity of genistein found in soybean against T. castaneum cultured cells within 24 h period. Genistein may be used as an oral toxin biopesticide against T. castaneum.

Stored grain pest prevalence and insecticide resistance in Egyptian populations of the red flour beetle Tribolium castaneum (Herbst) and the rice weevil Sitophilus oryzae (L.)

As a consequence of the widespread use of insecticides against insect pests in grain warehouses and in the food industry, insecticide resistance has greatly increased among these species all over the world. Nonetheless, insecticide resistance in stored grain insects in Egypt was little studied. Therefore, our study aimed to forecast infestation risks and determine the insecticide resistance level in Egyptian populations of the main insect pests of stored grains. To achieve this goal, we surveyed the populations of stored-product insects in wheat in two different sites in the Alexandria governorate (Egypt) between June and August 2017. Moreover, insecticide resistance levels in Egyptian populations of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.) collected from wheat storage facilities (granaries and flour mills) in Alexandria governorate were also determined. Three contact insecticides, namely malathion, pirimiphos-methyl and cypermethrin, were tested. Tarsal contact bioassays on filter paper were carried out on adults following FAO methods and concentration-mortality lines were estimated to determine the resistance ratios for each insecticide and population. The data from the monitoring of insects revealed that T. castaneum and S. oryzae were the most common species infesting wheat in both Alexandria granaries and mills. Populations of S. oryzae were generally more resistant to malathion than the populations of T. castaneum. However, T. castaneum populations were more resistant to pirimiphos-methyl than the S. oryzae populations. Both populations of T. castaneum and S. oryzae were susceptible to cypermethrin. The detected levels of insecticide resistance indicate that this phenomenon takes place and should be a concern in Egyptian populations of T. castaneum and S. oryzae requiring monitoring and design of resistance management practices.

Management of rust red flour beetle (Tribolium castaneum) in stored sesame

Red rust flour beetle (Tribolium castaneum Herbst) is one of the major constraints of stored sesame in India. They damage the stored-sesame seed by feeding, and severely reducing the quality of seed due to product excrement and larval feces. Experiment was conducted to evaluate the persistency of chemicals and plant products to manage T. castaneum in stored sesame. The data revealed that spinosad 45SC was the most effective treatment and recorded highest mortality of adult beetles at 24th, 5th after release during first (83.75% and 100%), second (73.13% and 79.38%) and third months (68.75% and 80.63%) after release. NSK and neem leaf powder were also found effective and recorded 93.75 and 86.25%, 85 and 73.75% and 81.25 and 72.50% mortality of beetles at 25th day after release during1st , 2nd and 3rd months after release respectively.

Six3 acts upstream of foxQ2 in labrum and neural development in the spider Parasteatoda tepidariorum

Anterior patterning in animals is based on a gene regulatory network, which comprises highly conserved transcription factors like six3, pax6 and otx. More recently, foxQ2 was found to be an ancestral component of this network but its regulatory interactions showed evolutionary differences. In most animals, foxQ2 is a downstream target of six3 and knockdown leads to mild or no epidermal phenotypes. In contrast, in the red flour beetle Tribolium castaneum, foxQ2 gained a more prominent role in patterning leading to strong epidermal and brain phenotypes and being required for six3 expression. However, it has remained unclear which of these novel aspects were insect or arthropod specific. Here, we study expression and RNAi phenotype of the single foxQ2 ortholog of the spider Parasteatoda tepidariorum. We find early anterior expression similar to the one of insects. Further, we show an epidermal phenotype in the labrum similar to the insect phenotype. However, our data indicate that foxQ2 is positioned downstream of six3 like in other animals but unlike insects. Hence, the epidermal and neural pattering function of foxQ2 is ancestral for arthropods while the upstream role of foxQ2 may have evolved in the lineage leading to the insects.

Effects of low-pressure storage of food commodities on the mortality of adult stored product insects

The food industry faces serious problems regarding pest infestation leading to high storage loss of food commodities. Due to adverse impacts of chemical preservation methods, a promising physical method of food protection could be considered as an urgent need. This study investigated the effect of low-pressure (vacuum) on the mortality of adults of three stored product pests of drug store beetle (Stegobium paniceum L.), southern cowpea weevil (Callosobruchus chinensis L.) and red flour beetle (Tribolium castaneum Herbst). The pests were exposed to 20 kPa and 10 kPa vacuum at 37 ºC and 75% relative humidity. Mortality of the insects was recorded at 8 h and 32 h after vacuum treatments. There were significant differences (p<0.05) in the susceptibility to the vacuum treatment among the tested pests. Adults of C. chinensis showed comparatively less susceptibility to the vacuum treatment compared to S. paniceum and T. castaneum. Mortality of insects exposed to two low-pressure treatments did not show 100% mortality at the two exposure periods, irrespective of the type of food materials and species. The mean percentage mortality increased by about 66.0±5.7% when vacuum pressure increases from 20 kPa to 10 kP irrespective of the species, exposure time and the products. The oxygen concentration decreased to >70% inside the vacuum chamber during treatments.

Adult neurogenesis in the mushroom bodies of red flour beetles (Tribolium castaneum, Herbst) is influenced by the olfactory environment

Several studies showed adult persisting neurogenesis in insects, including the red flour beetle Tribolium castaneum, while it is absent in honeybees, carpenter ants, and vinegar flies. In our study, we focus on cell proliferation in the adult mushroom bodies of T. castaneum. We reliably labelled the progenies of the adult persisting mushroom body neuroblasts and determined the proliferation rate under several olfactory conditions within the first week after adult eclosion. We found at least two phases of Kenyon cell proliferation in the early adult beetle. Our results suggest that the generation of Kenyon cells during the first three days after adult eclosion is mainly genetically predetermined and a continuation of the developmental processes (nature), whereas from day four on proliferation seems to be mainly dependent on the odour environment (nurture). Considering that the mushroom bodies are linked to learning and memory, neurogenesis in the mushroom bodies is part of the remodelling of neuronal circuits leading to the adaption to the environment and optimization of behaviour.

Methoprene-tolerant is essential for embryonic development of the red flour beetle Tribolium castaneum

Insect juvenile hormone (JH) is well known to regulate post-embryonic development and reproduction in concert with ecdysteroids in a variety of insect species. In contrast, our knowledge on the role of JH in embryonic development is limited and inconsistent. Preceding studies indicate that JH biosynthesis or JH signaling genes are dispensable in holometabolous Drosophila melanogaster and Bombyx mori, while essential in hemimetabolous Blattella germanica. In the red flour beetle Tribolium castaneum, we performed functional analyses of key factors in JH signaling, i.e. the JH receptor Methoprene-tolerant (Met) and the early JH-response gene Krüppel homolog 1 (Kr-h1) using parental RNA interference. Knockdown of Met resulted in a significant reduction in hatching rates and survival rates in the first and second larval instars. Meanwhile, knockdown of Kr-h1 caused no significant effect on hatching or survival. The unhatched embryos under Met knockdown developed up to the late embryonic stage, but their body shape was flat and tubby compared with the controls. Attempts to suppress JH biosynthesis by parental RNA interference of JH biosynthetic enzymes were unsuccessful due to insufficient knockdown efficiency. These results suggested that Met but not Kr-h1 is essential for the embryonic development of T. castaneum, although involvement of JH still remains to be examined. Taken together, the function of Met in embryonic development seems to be diverse among insect species.

Mining histone methyltransferases and demethylases from whole genome sequence

Epigenetic regulation through post-translational modification of histones, especially methylation, is well conserved in evolution. Although there are several insect genomes sequenced, an analysis with a focus on their epigenetic repertoire is limited. We have utilized a novel work-flow to identify one or more domains as highpriority domain (HPD), if present in at least 50% of the genes of a given functional class in the reference genome, namely, that of Drosophila melanogaster. Based on this approach, we have mined histone methyltransferases and demethylases from the whole genome sequence of Aedes aegypti (Diptera), the pea aphid Acyrthosiphon pisum, the triatomid bug Rhodnius prolixus (Hemiptera), the honeybee Apis mellifera (Hymenoptera), the silkworm Bombyx mori (Lepidoptera) and the red flour beetle Tribolium castaneum (Coleoptera). We identified 38 clusters consisting of arginine methyltransferases, lysine methyltransferases and demethylases using OrthoFinder, and the presence of HPD was queried in these sequences using InterProScan. This approach led us to identify putative novel members and currently inaccurate ones. Other than the highpriority domains, these proteins contain shared and unique domains that can mediate protein-protein interaction. Phylogenetic analysis indicates that there is different extent of protein sequence similarity; average similarity between histone lysine methyltransferases varies from 41% (for active mark) to 48% (for repressive mark), arginine methyltransferases is 51%, and demethylases is 52%. The method utilized here facilitates reliable identification of desired functional class in newly sequenced genomes.

Enhanced genome assembly and a new official gene set for Tribolium castaneum

BackgroundThe red flour beetle Tribolium castaneum has emerged as an important model organism for the study of gene function in development and physiology, for ecological and evolutionary genomics, for pest control and a plethora of other topics. RNA interference (RNAi), transgenesis and genome editing are well established and the resources for genome-wide RNAi screening have become available in this model. All these techniques depend on a high quality genome assembly and precise gene models. However, the first version of the genome assembly was generated by Sanger sequencing, and with a small set of RNA sequence data limiting annotation quality.ResultsHere, we present an improved genome assembly (Tcas5.2) and an enhanced genome annotation resulting in a new official gene set (OGS3) for Tribolium castaneum, which significantly increase the quality of the genomic resources. By adding large-distance jumping library DNA sequencing to join scaffolds and fill small gaps, the gaps in the genome assembly were reduced and the N50 increased to 4753kbp. The precision of the gene models was enhanced by the use of a large body of RNA-Seq reads of different life history stages and tissue types, leading to the discovery of 1452 novel gene sequences. We also added new features such as alternative splicing, well defined UTRs and microRNA target predictions. For quality control, 399 gene models were evaluated by manual inspection. The current gene set was submitted to Genbank and accepted as a RefSeq genome by NCBI.ConclusionsThe new genome assembly (Tcas5.2) and the official gene set (OGS3) provide enhanced genomic resources for genetic work in Tribolium castaneum. The much improved information on transcription start sites supports transgenic and gene editing approaches. Further, novel types of information such as splice variants and microRNA target genes open additional possibilities for analysis.

Insecticidal Activity of Chromobacterium phragmitis, a Recently Described Bacterium from Tidal Marshes

Several isolates of the recently described bacterial species Chromobacterium phragmitis Blackburn et al. were obtained from water collected from low-salinity tidal marshes in Maryland and Virginia. Bacteria were cultured in a liquid medium and applied to artificial diets in the laboratory. One of two Maryland isolates, IIBBL 113-1, was highly toxic to larvae of the cabbage looper Trichoplusia ni (Hübner) and the diamondback moth, Plutella xylostella (L.). The other Maryland isolate, IIBBL 112-1T, and the Virginia isolates were less toxic to these species. Maryland isolates were toxic to larvae of the seedcorn maggot Delia platura (Meigen), while a Virginia isolate, IIBBL 274-1, was of intermediate toxicity against D. platura. The C. phragmitis isolate IIBBL 113-1 was toxic to adults of the red flour beetle Tribolium castaneum (Herbst), while other C. phragmitis isolates had no activity against this species.

Effect of Tribolium castaneum in Qualitative and Quantitative Contamination with Fungi

The objective of this study was to estimate the quantitative contamination fungi in sound whole flour that infested with red flour beetle Tribolium castaneum under the effect of different numerical levels of insect, which are (5, 10, 20) pairs in the level of contamination. The study was accomplished under a temperature 30±2 0C and humidity 70 ±5%. The result showed the following. 13 species of fungus which belong to five genera were isolated from sound and infested whole flour samples with three numerical levels of the insect. These were (5, 10, 20) pairs and for two generations. The species isolated were: Aspergillus flavesus, A niger, A. terreus, Mucor hiemalis, Alternaria Alternaria, Paecilomyces Sp. Penicillium sp1, Penicillium sp2. Whereas at the two numerical levels (10, 20) pairs of insects, the fungus species Sterils mycelia, A.ustus, Emericella sp, Sepedonium sp. were isolated. The more frequently fungus in the samples of infested flour in the level 20 pairs of insects was A. flavus. Its frequency was (47.37%), also in level 5 pairs of the fungus A niger, which frequency ratio was (42, 58%). In the sound flour samples the more frequency. A. fumigates in level 5 pairs of insects which its frequency was (34, 48%) and in level 20 pairs of insects was the fungus A. niger which its frequency was (66.6%).The results showed that the rate of numerical of fungi increased with increasing levels of numbers of the insects ,the highest rate of fungus numerical was recorded in infested whole flours at the numerical level 10 pairs of insects was (31.41X10)2 colony/ gm. While their average numbers were (15.83×102) colony /gm at level 5 pairs of insects. It was observed that the average number of fungus in flour insects was higher than their numbers in sound flour.

Screening of wheat varieties for resistance to rust red flour beetle tribolium castaneum (Herbst)

Screening of wheat varieties for resistance to rust red flour beetle tribolium castaneum (Herbst)

The impact of local population genetic background on the spread of the selfish element Medea-1 in red flour beetles.

Selfish genetic elements have been found in the genomes of many species, yet our understanding of their evolutionary dynamics is only partially understood. A number of distinct selfish Medea elements are naturally present in many populations of the red flour beetle (Tribolium castaneum). Although these Medea elements are predicted by models to increase in frequency within populations because any offspring of a Medea‐bearing mother that do not inherit at least one Medea allele will die, experiments demonstrating an increase in a naturally occurring Medea element are lacking. Our survey of the specific Medea element, M1, in the United States showed that it had a patchy geographic distribution. From the survey, it could not be determined if this distribution was caused by a slow process of M1 colonization of discrete populations or if some populations lacked M1 because they had genetic factors conferring resistance to the Medea mechanism. We show that populations with naturally low to intermediate M1 frequencies likely represent transient states during the process of Medea spread. Furthermore, we find no evidence that genetic factors are excluding M1 from US populations where the element is not presently found. We also show how a known suppressor of Medea can impair the increase of M1 in populations and discuss the implications of our findings for pest‐management applications of Medea elements.