红脂大小蠹后肠挥发性物质的鉴定、触角电位和室内趋向实验

对外来松树害虫红脂大小蠹Dendroctonus valens LeConte的信息化学物质进行了研究。通过GC-MS测定,鉴定出红脂大小蠹后肠挥发性物质中除了含有松树挥发性物质α-蒎烯、β-蒎烯、3-蒈烯、月桂烯和柠檬烯外,还含有马鞭草烯醇和马鞭草烯酮;利用触角电位技术,对马鞭草烯醇、马鞭草烯酮以及在林间引诱效果最好的3-(+)-蒈烯进行了触角电生理测试;利用Y-型双向选择嗅觉仪对这些物质进行了室内趋向实验。实验结果表明: 1 μg的马鞭草烯醇、马鞭草烯酮和3-(+）-蒈烯引起雌雄触角的电位反应分别达416 μV/470 μV、597 μV/630 μV和926 μV/1 099 μV。浓度为1 μL/mL的马鞭草烯酮引起红脂大小蠹的正趋向反应,而在100 μL/mL浓度下引起红脂大小蠹的负趋向反应;在1 μL/mL的浓度下,3-(+ )-蒈烯引起了红脂大小蠹正趋向反应,而马鞭草烯醇则对红脂大小蠹具有驱避作用,说明这些物质在红脂大小蠹搜寻寄主和调节虫口密度方面起着重要作用。     

Verbenone-releasing flakes protect individual Pinus contorta trees from attack by Dendroctonus ponderosae and Dendroctonus valens (Coleoptera: Curculionidae, Scolytinae)

1 In a study site in interior northern California, twenty individual lodgepole pines Pinus contorta were sprayed with a suspension of DISRUPT Micro‐Flake^® Verbenone (4,6,6‐trimethylbicyclo(3.1)hept‐3‐en‐2‐one) Bark Beetle Anti‐Aggregant flakes (Hercon Environmental, Emigsville, Pennsylvania) in water, with sticker and thickener, from ground level to a height of 7 m. Twenty trees sprayed with just water, sticker and thickener served as controls. All trees were baited immediately after spraying with mountain pine beetle Dendroctonus ponderosae aggregation pheromone lures, and lures were refreshed after 4 weeks. 2 Trees treated with verbenone had significantly lower attack density by D. ponderosae than controls at 2, 4, 6 and 8 weeks after application of flakes. 3 None of the treated trees was attacked by red turpentine beetle Dendroctonus valens, whereas control trees averaged nearly two D. valens attacks per tree, 8 weeks after treatment. 4 A dry frass index, used to predict ultimate tree mortality, was significantly higher in control trees than treated trees for all four sampling intervals. This index proved to be a significant predictor of ultimate tree mortality. 5 Ten months after application, treated trees showed significantly lower mortality than control trees.     

An integrated overview of the bacterial flora composition of Hyalomma anatolicum,the main vector of CCHF

The microbial flora associated with Hyalomma anatolicum ticks was investigated using culture-dependent (CD) and independent (next generation sequencing, NGS) methods. The bacterial profiles of different organs, development stages, sexes, and of host cattle skins were analyzed using the CD method. The egg and female gut microbiota were investigated using NGS. Fourteen distinct bacterial strains were identified using the CD method, of which Bacillus subtilis predominated in eggs, larval guts and in adult female and male guts, suggesting probable transovarial transmission. Bacillus velezensis and B. subtilis were identified in cattle skin and tick samples, suggesting that skin is the origin of tick bacteria. H.anatolicum males harbour lower bacterial diversity and composition than females. The NGS analysis revealed five different bacterial phyla across all samples, Proteobacteria contributing to >95% of the bacteria. In all, 56611sequences were generated representing 6,023 OTUs per female gut and 421 OTUs per egg. Francisellaceae family and Francisella make up the vast majority of the OTUs. Our findings are consistent with interference between Francisella and Rickettsia. The CD method identified bacteria, such B. subtilis that are candidates for vector control intervention approaches such paratransgenesis whereas NGS revealed high Francisella spp. prevalence, indicating that integrated methods are more accurate to characterize microbial community and diversity.     

Metamorphosis of a Butterfly-Associated Bacterial Community

Butterflies are charismatic insects that have long been a focus of biological research. They are also habitats for microorganisms, yet these microbial symbionts are little-studied, despite their likely importance to butterfly ecology and evolution. In particular, the diversity and composition of the microbial communities inhabiting adult butterflies remain uncharacterized, and it is unknown how the larval (caterpillar) and adult microbiota compare. To address these knowledge gaps, we used Illumina sequencing of 16S rRNA genes from internal bacterial communities associated with multiple life stages of the neotropical butterfly Heliconius erato. We found that the leaf-chewing larvae and nectar- and pollen-feeding adults of H. erato contain markedly distinct bacterial communities, a pattern presumably rooted in their distinct diets. Larvae and adult butterflies host relatively small and similar numbers of bacterial phylotypes, but few are common to both stages. The larval microbiota clearly simplifies and reorganizes during metamorphosis; thus, structural changes in a butterfly''s bacterial community parallel those in its own morphology. We furthermore identify specific bacterial taxa that may mediate larval and adult feeding biology in Heliconius and other butterflies. Although male and female Heliconius adults differ in reproductive physiology and degree of pollen feeding, bacterial communities associated with H. erato are not sexually dimorphic. Lastly, we show that captive and wild individuals host different microbiota, a finding that may have important implications for the relevance of experimental studies using captive butterflies.     

Symbiotic Bacteria in Gills and Guts of Chinese Mitten Crab (Eriocheir sinensis) Differ from the Free-Living Bacteria in Water

Aquatic animals have a close relationship with water, but differences in their symbiotic bacteria and the bacterial composition in water remains unclear. Wild or domestic Chinese mitten crabs (Eriocheir sinensis) and the water in which they live were collected from four sampling sites in Jiangsu and Shanghai, China. Bacterial composition in water, gills or guts of E. sinensis, were compared by high-throughput sequencing using 16S rRNA genes. Analysis of >660,000 sequences indicated that bacterial diversity was higher in water than in gills or guts. Tenericutes and Proteobacteria were dominant phyla in guts, while Actinobacteria, Proteobacteria and Bacteroidetes were dominant in gills and water. Non-metric multidimensional scaling analysis indicated that microbiota from gills, guts or water clearly separated into three groups, suggesting that crabs harbor a more specific microbial community than the water in which they live. The dominant OTUs in crab gut were related to Mycoplasmataceae, which were low in abundance in gills, showing that, like mammals, crabs have body-site specific microbiota. OTUs related to Ilumatobacter and Albimonas, which are commonly present in sediment and seawater, were dominant in gills but almost absent from the sampled water. Considering E. sinensis are bottom-dwelling crustacean and they mate in saline water or seawater, behavior and life cycle of crabs may play an important role in shaping the symbiotic bacterial pattern. This study revealed the relationship between the symbiotic bacteria of Chinese mitten crab and their habitat, affording information on the assembly factors of commensal bacteria in aquatic animals.     

Analysis of the Gut Microbiota by High-Throughput Sequencing of the V5–V6 Regions of the 16S rRNA Gene in Donkey

Considerable evidence suggests that the gut microbiota is complex in many mammals and gut bacteria communities are essential for maintaining gut homeostasis. To date the research on the gut microbiota of donkey is surprisingly scarce. Therefore, we performed high-throughput sequencing of the 16S rRNA genes V5–V6 hypervariable regions from gut fecal material to characterize the gut microbiota of healthy donkeys and compare the difference of gut microbiota between male and female donkeys. Sixty healthy donkeys (30 males and 30 females) were enrolled in the study, a total of 915,691 validated reads were obtained, and the bacteria found belonged to 21 phyla and 183 genera. At the phylum level, the bacterial community composition was similar for the male and female donkeys and predominated by Firmicutes (64 % males and 64 % females) and Bacteroidetes (23 % males and 21 % females), followed by Verrucomicrobia, Euryarchaeota, Spirochaetes, and Proteobacteria. At the genus level, Akkermansia was the most abundant genus (23 % males and 17 % females), followed by Sporobacter, Methanobrevibacter, and Treponema, detected in higher distribution proportion in males than in females. On the contrary, Acinetobacter and Lysinibacillus were lower in males than in females. In addition, six phyla and 15 genera were significantly different between the male and female donkeys for species abundance. These findings provide previously unknown information about the gut microbiota of donkeys and also provide a foundation for future investigations of gut bacterial factors that may influence the development and progression of gastrointestinal disease in donkey and other animals.     

The inconstant gut microbiota of Drosophila species revealed by 16S rRNA gene analysis

The gut microorganisms in some animals are reported to include a core microbiota of consistently associated bacteria that is ecologically distinctive and may have coevolved with the host. The core microbiota is promoted by positive interactions among bacteria, favoring shared persistence; its retention over evolutionary timescales is evident as congruence between host phylogeny and bacterial community composition. This study applied multiple analyses to investigate variation in the composition of gut microbiota in drosophilid flies. First, the prevalence of five previously described gut bacteria (Acetobacter and Lactobacillus species) in individual flies of 21 strains (10 Drosophila species) were determined. Most bacteria were not present in all individuals of most strains, and bacterial species pairs co-occurred in individual flies less frequently than predicted by chance, contrary to expectations of a core microbiota. A complementary pyrosequencing analysis of 16S rRNA gene amplicons from the gut microbiota of 11 Drosophila species identified 209 bacterial operational taxonomic units (OTUs), with near-saturating sampling of sequences, but none of the OTUs was common to all host species. Furthermore, in both of two independent sets of Drosophila species, the gut bacterial community composition was not congruent with host phylogeny. The final analysis identified no common OTUs across three wild and four laboratory samples of D. melanogaster. Our results yielded no consistent evidence for a core microbiota in Drosophila. We conclude that the taxonomic composition of gut microbiota varies widely within and among Drosophila populations and species. This is reminiscent of the patterns of bacterial composition in guts of some other animals, including humans.     

Hidden Diversity in Honey Bee Gut Symbionts Detected by Single-Cell Genomics

Microbial communities in animal guts are composed of diverse, specialized bacterial species, but little is known about how gut bacteria diversify to produce genetically and ecologically distinct entities. The gut microbiota of the honey bee, Apis mellifera, presents a useful model, because it consists of a small number of characteristic bacterial species, each showing signs of diversification. Here, we used single-cell genomics to study the variation within two species of the bee gut microbiota: Gilliamella apicola and Snodgrassella alvi. For both species, our analyses revealed extensive variation in intraspecific divergence of protein-coding genes but uniformly high levels of 16S rRNA similarity. In both species, the divergence of 16S rRNA loci appears to have been curtailed by frequent recombination within populations, while other genomic regions have continuously diverged. Furthermore, gene repertoires differ markedly among strains in both species, implying distinct metabolic capabilities. Our results show that, despite minimal divergence at 16S rRNA genes, in situ diversification occurs within gut communities and generates bacterial lineages with distinct ecological niches. Therefore, important dimensions of microbial diversity are not evident from analyses of 16S rRNA, and single cell genomics has potential to elucidate processes of bacterial diversification.     

Insect Gut Bacterial Diversity Determined by Environmental Habitat,Diet, Developmental Stage,and Phylogeny of Host

Insects are the most abundant animals on Earth, and the microbiota within their guts play important roles by engaging in beneficial and pathological interactions with these hosts. In this study, we comprehensively characterized insect-associated gut bacteria of 305 individuals belonging to 218 species in 21 taxonomic orders, using 454 pyrosequencing of 16S rRNA genes. In total, 174,374 sequence reads were obtained, identifying 9,301 bacterial operational taxonomic units (OTUs) at the 3% distance level from all samples, with an average of 84.3 (±97.7) OTUs per sample. The insect gut microbiota were dominated by Proteobacteria (62.1% of the total reads, including 14.1% Wolbachia sequences) and Firmicutes (20.7%). Significant differences were found in the relative abundances of anaerobes in insects and were classified according to the criteria of host environmental habitat, diet, developmental stage, and phylogeny. Gut bacterial diversity was significantly higher in omnivorous insects than in stenophagous (carnivorous and herbivorous) insects. This insect-order-spanning investigation of the gut microbiota provides insights into the relationships between insects and their gut bacterial communities.     

Bacterial Community and Nitrogen Fixation in the Red Turpentine Beetle, <Emphasis Type="Italic">Dendroctonus valens</Emphasis> LeConte (Coleoptera: Curculionidae: Scolytinae)

The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), colonizes all pines species within its native range throughout North and Central America. Recently, this species was accidentally introduced to China, where it has caused severe damage in pine forests. It belongs to a group of beetles that spend most of their lives between the tree bark and sapwood, where it feeds on phloem: a poor substrate with very low nutritional value of nitrogen and toxic properties due to its high content of secondary defensive compounds. The aim of this study was to characterize the bacterial community of the D. valens gut by culture-dependent and -independent methods. Polymerase chain reaction denaturing gradient gel electrophoresis and ribosomal gene library analyses revealed that species diversity in the D. valens gut was relatively low, containing between six and 17 bacterial species. The bacterial community associated with larvae and adults was dominated by members of the following genera: Lactococcus, Acinetobacter, Pantoea, Rahnella, Stenothrophomonas, Erwinia, Enterobacter, Serratia, Janibacter, Leifsonia, Cellulomonas, and Cellulosimicrobium. The members of the last four genera showed cellulolytic activity in vitro and could be involved in cellulose breakdown in the insect gut. Finally, nitrogen fixation was demonstrated in live larvae and adults; however, capacity of nitrogen fixing in vitro was not found among enterobacterial species isolated in nitrogen-free media; neither were nifD nor nifH genes detected. In contrast, nifD gen was detected in metagenomic DNA from insect guts. The identification of bacterial species and their potential physiological capacities will allow exploring the role of gut symbiotic bacteria in the adaptation and survival of D. valens in a harsh chemical habitat poor in nitrogen sources.     

Immunocompetence of the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae): Variation between developmental stages and sexes in populations in China

Immune defense imposes fitness costs as well as benefits, so organisms should optimize, not maximize, their immune function through their life cycle. We investigated this issue in the red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), which is a pine-killing invasive beetle in China, though it is usually considered as a secondary pest in its native range of North America. We hypothesized that pathogen pressure may affect these beetles differently throughout their life history. We measured the insect's immunocompetence throughout life, determining encapsulation ability and phenoloxidase activity in larval stages, pupae and adults. Pupae had the highest encapsulation ability, but encapsulation was not different between final instar larvae and adults. Phenoloxidase (PO) activity was highest in final instar larvae and pupae, followed by the second instar larvae and adults. Total phenoloxidase activity increased significantly from the second instar larval stage to pupae, and then decreased in adults. Although the second instar larvae had the lowest phenoloxidase activity, more than 90% of total PO existed in the hemolymph in the form of the active enzyme, as compared with pupae, in which over 60% of PO occurred as a proenzyme. Both active PO and total PO were much higher in females than in males, though no significant differences were detected between the encapsulation ability of male and female adults. This result suggests the existence of a sexual dimorphism of immunocompetence in D. valens adults. Variations in immunocompetence across developmental stages suggest that D. valens adopts diverse investment strategies in immunocompetence during different stages. Potential reasons for variation in immunocompetence among developmental stages and between the sexes of D. valens are discussed.     

Comparison of Euryarchaea Strains in the Guts and Food-Soil of the Soil-Feeding Termite Cubitermes fungifaber across Different Soil Types

Termites are an important component of tropical soil communities and have a significant effect on the structure and nutrient content of soil. Digestion in termites is related to gut structure, gut physicochemical conditions, and gut symbiotic microbiota. Here we describe the use of 16S rRNA gene sequencing and terminal-restriction fragment length polymorphism (T-RFLP) analysis to examine methanogenic archaea (MA) in the guts and food-soil of the soil-feeder Cubitermes fungifaber Sjostedt across a range of soil types. If these MA are strictly vertically inherited, then the MA in guts should be the same in all individuals even if the soils differ across sites. In contrast, gut MA should reflect what is present in soil if populations are merely a reflection of what is ingested as the insects forage. We show clear differences between the euryarchaeal communities in termite guts and in food-soils from five different sites. Analysis of 16S rRNA gene clones indicated little overlap between the gut and soil communities. Gut clones were related to a termite-derived Methanomicrobiales cluster, to Methanobrevibacter and, surprisingly, to the haloalkaliphile Natronococcus. Soil clones clustered with Methanosarcina, Methanomicrococcus, or rice cluster I. T-RFLP analysis indicated that the archaeal communities in the soil samples differed from site to site, whereas those in termite guts were similar between sites. There was some overlap between the gut and soil communities, but these may represent transient populations in either guts or soil. Our data do not support the hypothesis that termite gut MA are derived from their food-soil but also do not support a purely vertical transmission of gut microflora.     

Yeast Diversity Associated with Invasive Dendroctonus valens Killing Pinus tabuliformis in China Using Culturing and Molecular Methods

Bark beetle-associated yeasts are much less studied than filamentous fungi, yet they are also considered to play important roles in beetle nutrition, detoxification, and chemical communication. The red turpentine beetle, Dendroctonus valens, an invasive bark beetle introduced from North America, became one of the most destructive pests in China, having killed more than 10 million Pinus tabuliformis as well as other pine species. No investigation of yeasts associated with this bark beetle in its invaded ranges has been conducted so far. The aim of this study was to assess the diversity of yeast communities in different microhabitats and during different developmental stages of Den. valens in China using culturing and denaturing gradient gel electrophoresis (DGGE) approaches and to compare the yeast flora between China and the USA. The yeast identity was confirmed by sequencing the D1/D2 domain of LSU ribosomal DNA (rDNA). In total, 21 species (13 ascomycetes and eight basidiomycetes) were detected by culturing method, and 12 species (11 ascomycetes and one basidiomycetes) were detected by molecular methods from China. The most frequent five species in China were Candida piceae (Ogataea clade), Cyberlindnera americana, Candida oregonensis (Metschnikowia clade), Candida nitratophila (Ogataea clade) and an undescribed Saccharomycopsis sp., detected by both methods. Seven species were exclusively detected by DGGE. Ca. oregonensis (Metschnikowia clade) was the most frequently detected species by DGGE method. Eight species (all were ascomycetes) from the USA were isolated; seven of those were also found in China. We found significant differences in yeast total abundance as well as community composition between different developmental stages and significant differences between the surface and the gut. The frass yeast community was more similar to that of Den. valens surface or larvae than to the community of the gut or adults. Possible functions of the yeast associates are discussed.     

Cecal microbiome divergence of broiler chickens by sex and body weight

The divergence of gut bacterial community on broiler chickens has been reported as potentially possible keys to enhancing nutrient absorption, immune systems, and increasing poultry health and performance. Thus, we compared cecal bacterial communities and functional predictions by sex and body weight regarding the association between cecal microbiota and chicken growth performance. In this study, a total of 12 male and 12 female 1-day-old broiler chickens were raised for 35 days in 2 separate cages. Chickens were divided into 3 subgroups depending on body weight (low, medium, and high) by each sex. We compared chicken cecal microbiota compositions and its predictive functions by sex and body weight difference. We found that bacterial 16S rRNA genes were classified as 3 major phyla (Bacteroidetes, Firmicutes, and Proteobacteria), accounting for > 98% of the total bacterial community. The profiling of different bacterial taxa and predictive metagenome functions derived from 16S rRNA genes were performed over chicken sex and bodyweight. Male chickens were related to the enrichment of Bacteroides while female chickens were to the enrichment of Clostridium and Shigella. Male chickens with high body weight were associated with the enrichment of Faecalibacterium and Shuttleworthia. Carbohydrate and lipid metabolisms were suggested as candidate functions for weight gain in the males. This suggests that the variation of cecal bacterial communities and their functions by sex and body weight may be associated with the differences in the growth potentials of broiler chickens.     

Pyrosequencing analysis of the bacterial communities in the guts of honey bees Apis cerana and Apis mellifera in Korea

The bacterial communities in the guts of the adults and larvae of the Asian honey bee Apis cerana and the European honey bee Apis mellifera were surveyed by pyrosequencing the 16S rRNA genes. Most of the gut bacterial 16S rRNA gene sequences were highly similar to the known honey bee-specific ones and affiliated with Pasteurellaceae or lactic acid bacteria (LAB). The numbers of operational taxonomic units (OTUs, defined at 97% similarity) were lower in the larval guts (6 or 9) than in the adult guts (18 or 20), and the frequencies of Pasteurellaceae-related OTUs were higher in the larval guts while those of LAB-related OTUs in the adult guts. The frequencies of Lactococcus, Bartonella, Spiroplasma, Enterobacteriaceae, and Flavobacteriaceae-related OTUs were much higher in A. cerana guts while Bifidobacterium and Lachnospiraceae-related OTUs were more abundant in A. mellfera guts. The bacterial community structures in the midguts and hindguts of the adult honey bees were not different for A. cerana, but significantly different for A. mellifera. The above results substantiated the previous observation that honey bee guts are dominated by several specific bacterial groups, and also showed that the relative abundances of OTUs could be markedly changed depending on the developmental stage, the location within the gut, and the honey bee species. The possibility of using the gut bacterial community as an indicator of honey bee health was discussed.     

Comparative analysis of microbial diversity in Longitarsus flea beetles (Coleoptera: Chrysomelidae)

Herbivorous beetles comprise a significant fraction of eukaryotic biodiversity and their plant-feeding adaptations make them notorious agricultural pests. Despite more than a century of research on their ecology and evolution, we know little about the diversity and function of their symbiotic microbial communities. Recent culture-independent molecular studies have shown that insects possess diverse gut microbial communities that appear critical for their survival. In this study, we combined culture-independent methods and high-throughput sequencing strategies to perform a comparative analysis of Longitarsus flea-beetles microbial community diversity (MCD). This genus of beetle herbivores contains host plant specialists and generalists that feed on a diverse array of toxic plants. Using a deep-sequencing approach, we characterized the MCD of eleven Longitarsus species across the genus, several of which represented independent shifts to the same host plant families. Database comparisons found that Longitarsus-associated microbes came from two habitat types: insect guts and the soil rhizosphere. Statistical clustering of the Longitarsus microbial communities found little correlation with the beetle phylogeny, and uncovered discrepancies between bacterial communities extracted directly from beetles and those from frass. A Principal Coordinates Analysis also found some correspondence between beetle MCD and host plant family. Collectively, our data suggest that environmental factors play a dominant role in shaping Longitarsus MCD and that the root-feeding beetle larvae of these insects are inoculated by soil rhizosphere microbes. Future studies will investigate MCD of select Longitarsus species across their geographic ranges and explore the connection between the soil rhizosphere and the beetle MCD.     

Volatile constituents of male and female boll weevils and their frass

The volatile constituents of male and female boll weevils, Anthonomus grandis, and their frass were analysed by GLC-MS. The 4 previously identified components of the male pheromone were present only in the male volatile oil (3·9%) and in the male frass volatile oil (38·9%). The compounds found in one or both sexes and their frass include 26 carbonyls, 23 hydrocarbons, 12 alcohols, 6 phenols, 4 esters, 3 furans, 1 ether, and 1 lactone. Also found were 2 compounds containing nitrogen, 1 halogen, and 1 sulphur. There were 33 terpenes and 24 aromatic compounds. 3,7-Dimethyl-1-octanol comprised 15·6 per cent of the male frass oil. Carvone was found only in females (5·4%) and in female frass (6·8%). A series of monoterpene aldehydes (M⁺ 152) were found only in the female frass oil. A pheromone rôle for these components was suggested.     

Divergence in gut bacterial community between females and males in the wolf spider Pardosa astrigera

Sex is one of the important factors affecting gut microbiota. As key predators in agroforestry ecosystem, many spider species show dramatically different activity habits and nutritional requirements between females and males. However, how sex affects gut microbiota of spiders remains unclear. Here, we compared the composition and diversity of gut bacteria between female and male Pardosa astrigera based on bacterial 16S rRNA gene sequencing. Results showed that the richness of bacterial microbiota in female spiders was significantly lower than in male spiders (p < .05). Besides, β‐diversity showed a significant difference between female and male spiders (p = .0270). The relative abundance of Actinobacteriota and Rhodococcus (belongs to Actinobacteriota) was significantly higher in female than in male spiders (p < .05), whereas the relative abundance of Firmicutes and Acinetobacter (belongs to Proteobacteria) and Ruminococcus and Fusicatenibacter (all belong to Firmicutes) was significantly higher in male than in female spiders (p < .05). The results also showed that amino acid and lipid metabolisms were significantly higher in female than in male spiders (p < .05), whereas glycan biosynthesis and metabolism were significantly higher in male than in female spiders (p < .05). Our results imply that sexual variation is a crucial factor in shaping gut bacterial community in P. astrigera spiders, while the distinct differences of bacterial composition are mainly due to their different nutritional and energy requirements.     

An assessment of the life time biosynthesis potential of the male boll weevil

The four monoterpene compounds [1, (+)-cis-2-isopropenyl-1-methycyclobutaneethanol; II, (Z)-3,3-dimethyl-Δ^1,β-cyclohexaneethanol; III, (Z)-3,3-dimethyl-Δ^1,α-cyclohexaneacetaldehyde; and IV, (E)-3,3-dimethyl-Δ^1,α-cyclohexaneacetaldehyde] which comprise the pheromone of the male boll weevil, Anthonomus grandis, were determined daily throughout the lifespan of the insect by GLC analysis of the whole body and the frass. The total content of the components in the male is never greater than 210 ng, the average content in the frass produced during 1 day is 1268 ng, and the lifetime production is at least 40,000 ng. The ratio of the four components in frass is 6 : 6 : 2 : 1/I : II : III : IV. None of the four components was found in females, but female frass contained traces in three instances. These data can be used to compare the potential attractancy of insects from various geographical areas, at different seasons, in different nutritional states, and after chemosterilization. Such differences in potential insect attractiveness could be crucial to effective large-scale control programmes.