Prevalence of Wolbachia in 10 Tenebrionidae stored-product insects and spatiotemporal infection dynamics in Tribolium confusum(Jaquelin Du Val)(Coleoptera:Tenebrionidae)

Insect symbionts Wolbachia used for pest population control has focused on vector pest species and agricultural insects while rare reports in Chinese stored-product insect samples.In this paper,we surveyed the prevalence of Wolbachia using a PCR detection method in ten Tenebrionidae stored-product insects.Subsequently,the spatiotemporal Wolbachia infection dynamics in Tribolium confusum and Wolbachia elimination patterns using tetracycline treatment were investigated in detail by TaqMan®probe real-time quantitative PCR,and host reproductive fitness parameters were compared.T.confusum was the only Wolbachia infected species in all the surveyed species.Wolbachia infection density consistently increased with the development of T.confusumand plateaued at 3.7×107 wsp copies per individual insect at the young adult stage.Wolbachia densities in females were higher than that in males with a significant difference at the pupae stage and varied among different tissues and organs.Uninfected female beetles were completely incapable of producing mature progenies when crossed with Wolbachia infected males.Embryogenesis and egg hatch rate were specifically inhibited after Wolbachia elimination,while other traits,including the number of eggs,pupation rate and sex ratio,remained unaffected by tetracycline treatment.Our results showthat the TaqMan®probe qPCR is a reliable detection method for quantifying the density of Wolbachia as compared to qualitative detection of wsp gene by PCR and relatively quantified by real-time qPCR.The fitness results indicated that Wolbachia infection was not an obligate symbiont and benefited the host confused flour beetle.

Morphological and molecular identification of Xylocoris flavipes(Hemiptera:Anthocoridae)in southern China

During the investigation of natural enemy insects in grain depots,we've found an Anthocoridae insect accounted for a high proportion of natural enemy insects.We identify the enemy insects from morphology and molecular biology,so as to realize more accurate and effective control of storage pests by using the enemy insect.The images of the insects under the ultra-depth microscope(VHX-5000)showed that the insect adults were black brown in colour;the antennas of both the female and male had four segments,which increase in length sequentially from the base to the end,and had a length of 756.2μm for the female and 741.1μm for the male.The rostrums of both the female and the male insects were composed of three segments,the male's rostrum(596.8μm)were shorter than the female's(734.6μm),and the former two segments of the female's rostrum were significantly longer than the male's.The abdomen of the insect was bilaterally symmetrical,the female's abdomen was wider than the male,and the male insect had a dent between its eighth and ninth segments of the left abdomen,in which its male genitalia was located.In addition,the nymphs as a whole were tangerine in colour,and the eggs were elliptic with creamy white gloss and gridding patterns on the surface.The cytochrome C oxidase I(COI)gene sequences of the insects were identified by DNA barcoding technique,and the determined COI sequences were then submitted to the Genbank database for Blast alignment,and the results showed that the COI gene sequences had a high degree of similarity(99%)with X.flavipes records in the Genbank database.Therefore,we could determine that the insect was X.flavipes.In addition,the neighbor joining(NJ)was used to construct the evolutionary tree,and 1,000 repeated tests were conducted on the confidence levels of each branch.Based on the phylogenetic tree,we've found that X.flavipes belongs to Xylocoris genus.Based on morphology and COI sequence identification,we confidentiy determined that the collected natural enemy insect was X.flavipes.This is the first time that the identification of X.flavipes is being investigated from morphology and molecular biology.The research results are helpful to identify and distinguish the species of flower bugs,and beneficial for the better application of X.flavipes in biological control.

Potential use of Clerodendrum capitatum extracts and its formulation for control of three major stored product beetles

Objective:Insecticidal activity of Clerodendrum capitatum extracts against the stored product insect pest,Sitophilus oryzae(L.),Rhyzopertha dominica(F.),and Tribolium castaneum(Herbst)were investigated.Materials and Methods:Hundred grams of C.capitatum powder was sequentially extracted with a series of solvents of increasing polarity in a Soxhlet apparatus and the extracts were concentrated on rotary evaporator to make it solvent free and the residue dissolved in a known volume of methanol and the solution was assayed for insecticidal activity by the fumigant toxicity.Hexane extract which showed maximum activity was selected for the preparation of herbal formulation and for its insecticidal properties and phytotoxicity.The herbal formulation obtained from leaves of C.capitatum was investigated by GCMS and GC/FID.Results:Clerodendrum capitatum ethyl extract had a very strong repellent activity to adults of all three major stored grain insects and was significantly repellent at a 1.58 mg/cm^(2).The hexane extract(oil)had high fumigant activity with LC_(50) values in the range between 25 and 32μg/L.A total of 14 components representing 97.8%of the formulation were identified and the main compounds in the formulation were found to be 2-Heptanone,3-methyl(33.9%)and Hexahydrofarnesyl acetone(25.3%)followed by 3-Dodecen-1-al(10.2%)and 8-Methyl-1-undecene(4.9%).Further,herbal formulation was found to be highly toxic to mixed age cultures of all three major stored grain insect pests which recorded 80%-90%mortality at dose of 200μg/L in 24 h exposure,where as 100%mortality achieved at dose of 200μg/L in 72 h exposure,respectively.Conclusion:The results indicate that extracts and formulation of C.capitatum has the potential to be developed in to a natural insecticide or repellent for controlling of stored product beetles.