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This study aimed to understand how mindfulness meditation affects young people by examining its impact on self‐regulation, happiness, emotional awareness, and school performance among two groups of school children. A 10‐week mindfulness program was conducted by a meditation expert for 552 children aged 4–8 (Group 1) and 287 children aged 9–11 (Group 2). Results for the 4–8 years group (Group 1) showed meditation predicted an increase in happiness (R2 =.003, p <.001) and self‐reported school performance (R2 =.005, p <.001) and a decrease in emotional (R2 =.017, p <.001) and behavioral difficulties (R2 =.009, p <.001); however, the effect sizes were small. In the 9–11 years group (Group 2), meditation predicted an increase in emotional awareness (R2 =.02, p <.001), and a decrease in emotional (R2 =.014, p <.001) and behavioral difficulties (R2 =.009, p <.001) as measured by scores from baseline to postintervention. For Group 2, there was no significant change in happiness over the 10 weeks. The findings support incorporating mindfulness meditation in schools, noting significant enhancements in self‐regulation with just 5 min of daily practice. Practitioner Points: Daily meditation of just 5 min for 4–8‐year‐olds predicted an increase in happiness, self‐reported school performance, and a decrease in emotional and behavioral difficulties.Daily meditation of just 5 min in 9–11‐year‐olds predicted an increase in emotional awareness, and a decrease in emotional and behavioral difficulties, but no change in happiness.Daily meditation of just 5 min over 10 weeks enhanced self‐regulation in primary school children. [ABSTRACT FROM AUTHOR]

Dear Editor, Gut microorganisms process food in animal guts and release many metabolic by-products, which are predicted to influence host physiological processes such as energy and lipid metabolism. This effect has been attributed to the metabolic response of white adipose tissue to succinate, mediated by succinate binding to its cognate receptor succinate receptor 1 (SUCNR1/GPR91) to activate downstream signaling pathways that inhibit lipolysis (McCreath I et al i ., 2015). The effect of succinate on fly lipid is specific in two ways: (i) other nutritional indices were not significantly affected by dietary succinate; and (ii) fumarate, a metabolically related TCA cycle intermediate, did not reduce fly lipid content. [Extracted from the article]

Whiteflies possess bacterial symbionts Candidatus Portiera aleyrodidium that are housed in specialized cells called bacteriocytes and are faithfully transmitted via the ovary to insect offspring. In one whitefly species studied previously, Bemisia tabaci MEAM1, transmission is mediated by somatic inheritance of bacteriocytes, with a single bacteriocyte transferred to each oocyte and persisting through embryogenesis to the next generation. Here, we investigate the mode of bacteriocyte transmission in two whitefly species, B. tabaci MED, the sister species of MEAM1, and the phylogenetically distant species Trialeurodes vaporariorum. Microsatellite analysis supported by microscopical studies demonstrates that B. tabaci MED bacteriocytes are genetically different from other somatic cells and persist through embryogenesis, as for MEAM1, but T. vaporariorum bacteriocytes are genetically identical to other somatic cells of the insect, likely mediated by the degradation of maternal bacteriocytes in the embryo. These two alternative modes of transmission provide a first demonstration among insect symbioses that the cellular processes underlying vertical transmission of bacterial symbionts can diversify among related host species associated with a single lineage of symbiotic bacteria. [ABSTRACT FROM AUTHOR]

A defining feature of the nutritional ecology of plant sap‐feeding insects is that the dietary deficit of essential amino acids (EAAs) in plant sap is supplemented by EAA‐provisioning microbial symbionts in the insect. Here, we demonstrated substantial variation in the nutritional phenotype of 208 genotypes of the pea aphid Acyrthosiphon pisum collected from a natural population. Specifically, the genotypes varied in performance (larval growth rates) on four test diets lacking the EAAs arginine, histidine and methionine or aromatic EAAs (phenylalanine and tryptophan), relative to the diet containing all EAAs. These data indicate that EAA supply from the symbiotic bacteria Buchnera can meet total aphid nutritional demand for only a subset of the EAA/aphid genotype combinations. We then correlated single nucleotide polymorphisms (SNPs) identified in the aphid and Buchnera genomes by reduced genome sequencing against aphid performance for each EAA deletion diet. This yielded significant associations between performance on the histidine‐free diet and Buchnera SNPs, including metabolism genes predicted to influence histidine biosynthesis. Aphid genetic correlates of performance were obtained for all four deletion diets, with associations on the arginine‐free diet and aromatic‐free diets dominated by genes functioning in the regulation of metabolic and cellular processes. The specific aphid genes associated with performance on different EAA deletion diets are largely nonoverlapping, indicating some independence in the regulatory circuits determining aphid phenotype for the different EAAs. This study demonstrates how variation in the phenotype of associations collected from natural populations can be applied to elucidate the genetic basis of ecologically important traits in systems intractable to traditional forward/reverse genetic techniques. [ABSTRACT FROM AUTHOR]

Organisms are locally adapted when members of a population have a fitness advantage in one location relative to conspecifics in other geographies. For example, across latitudinal gradients, some organisms may trade off between traits that maximize fitness components in one, but not both, of somatic maintenance or reproductive output. Latitudinal gradients in life history strategies are traditionally attributed to environmental selection on an animal's genotype, without any consideration of the possible impact of associated microorganisms ("microbiota") on life history traits. Here, we show in Drosophila melanogaster, a key model for studying local adaptation and life history strategy, that excluding the microbiota from definitions of local adaptation is a major shortfall. First, we reveal that an isogenic fly line reared with different bacteria varies the investment in early reproduction versus somatic maintenance. Next, we show that in wild fruit flies, the abundance of these same bacteria was correlated with the latitude and life history strategy of the flies, suggesting geographic specificity of the microbiota composition. Variation in microbiota composition of locally adapted D. melanogaster could be attributed to both the wild environment and host genetic selection. Finally, by eliminating or manipulating the microbiota of fly lines collected across a latitudinal gradient, we reveal that host genotype contributes to latitude‐specific life history traits independent of the microbiota and that variation in the microbiota can suppress or reverse the differences between locally adapted fly lines. Together, these findings establish the microbiota composition of a model animal as an essential consideration in local adaptation. [ABSTRACT FROM AUTHOR]

Resident microorganisms are known to influence the fitness and traits of animals under controlled laboratory conditions, but the relevance of these findings to wild animals is uncertain. This study investigated the host functional correlates of microbiota composition in a wild community of three sympatric species of mycophagous drosophilid flies, Drosophila falleni, Drosophila neotestacea and Drosophila putrida. Specifically, we quantified bacterial communities and host transcriptomes by parallel 16S rRNA gene amplicon sequencing and RNA‐Seq of individual flies. Among‐fly variation in microbiota composition did not partition strongly by sex or species, and included multiple modules, that is, sets of bacterial taxa whose abundance varied in concert across different flies. The abundance of bacteria in several modules varied significantly with multiple host transcripts, especially in females, but the identity of the correlated host transcriptional functions differed with host species, including epithelial barrier function in D. falleni, muscle function in D. putrida, and insect growth and development in D. neotestacea. In D. neotestacea, which harbours the endosymbionts Wolbachia and Spiroplasma, Wolbachia promotes the abundance of Spiroplasma, and is positively correlated with abundance of Lactobacillales and Bacteroidales. Furthermore, most correlations between host gene expression and relative abundance of bacterial modules were co‐correlated with abundance of Wolbachia (but not Spiroplasma), indicative of an interdependence between host functional traits, microbiota composition and Wolbachia abundance in this species. These data suggest that, in these natural populations of drosophilid flies, different host species interact with microbial communities in functionally different ways that can vary with the abundance of endosymbionts. [ABSTRACT FROM AUTHOR]

Abstract: Most of the evidence that the gut microbiome of animals is functionally variable, with consequences for the health and fitness of the animal host, is based on laboratory studies, often using inbred animals under tightly controlled conditions. It is largely unknown whether these microbiome effects would be evident in outbred animal populations under natural conditions. In this study, we quantified the functional traits of the gut microbiota (metagenome) and host (gut transcriptome) and the taxonomic composition of the gut microorganisms (16S rRNA gene sequence) in natural populations of three mycophagous Drosophila species. Variation in microbiome function and composition was driven principally by the period of sample collection, while host function varied mostly with Drosophila species, indicating that variation in microbiome traits is determined largely by environmental factors, and not host taxonomy. Despite this, significant correlations between microbiome and host functional traits were obtained. In particular, microbiome functions dominated by metabolism were positively associated with host functions relating to gut epithelial turnover. Much of the functional variation in the microbiome could be attributed to variation in abundance of Bacteroidetes, rather than the two other abundant groups, the γ‐Proteobacteria or Lactobacillales. We conclude that functional variation in the interactions between animals and their gut microbiome can be detectable in natural populations, and, in mycophagous Drosophila, this variation relates primarily to metabolism and homeostasis of the gut epithelium. [ABSTRACT FROM AUTHOR]

Summary: Many symbiotic microorganisms in animals, including insects, have parallels to microbial nutrient factories of biotechnology: just as the metabolism of individual microorganisms and microbial communities is modified by biotechnologists to produce specific nutrients, so the many insect‐associated microorganisms synthesize specific nutrients that support the sustained growth and reproduction of their animal host. Three broad metabolic functions are mediated by insect‐associated microorganisms: (i) fermentation of dietary constituents, releasing products that contribute to host carbon and energy metabolism; (ii) overproduction of nutrients, notably essential amino acids, required by the host and (iii) recycling of host waste metabolites. In many systems, the nutrients that are released from living microbial cells have been identified, with evidence for metabolite cross‐feeding and shared metabolic pathways both among different microbial taxa and between microorganisms and the host. However, the flux of nutrients from microbial cells to host has rarely been quantified; our understanding of the processes that regulate nutrient transfer is fragmentary; and the scale and mechanism of metabolic adaptations of microorganisms to host nutritional demand are largely unknown. Recent advances in metabolic, microscopical and modelling techniques offer excellent opportunities to resolve these outstanding issues, with insights that can contribute to the effective design of nutrient factories for biotechnological applications. [ABSTRACT FROM AUTHOR]

Abstract: Despite evidence from laboratory experiments that perturbation of the gut microbiota affects many traits of the animal host, our understanding of the effect of variation in microbiota composition on animals in natural populations is very limited. The core purpose of this study on the fruit fly Drosophila melanogaster was to identify the impact of natural variation in the taxonomic composition of gut bacterial communities on host traits, with the gut transcriptome as a molecular index of microbiota‐responsive host traits. Use of the gut transcriptome was validated by demonstrating significant transcriptional differences between the guts of laboratory flies colonized with bacteria and maintained under axenic conditions. Wild Drosophila from six field collections made over two years had gut bacterial communities of diverse composition, dominated to varying extents by Acetobacteraceae and Enterobacteriaceae. The gut transcriptomes also varied among collections and differed markedly from those of laboratory flies. However, no overall relationship between variation in the wild fly transcriptome and taxonomic composition of the gut microbiota was evident at all taxonomic scales of bacteria tested for both individual fly genes and functional categories in Gene Ontology. We conclude that the interaction between microbiota composition and host functional traits may be confounded by uncontrolled variation in both ecological circumstance and host traits (e.g., genotype, age physiological condition) under natural conditions, and that microbiota effects on host traits identified in the laboratory should, therefore, be extrapolated to field population with great caution. [ABSTRACT FROM AUTHOR]

Various bacterial taxa have been identified both in association with animals and in the external environment, but the extent to which related bacteria from the two habitat types are ecologically and evolutionarily distinct is largely unknown. This study investigated the scale and pattern of genetic differentiation between bacteria of the family Acetobacteraceae isolated from the guts of Drosophila fruit flies, plant material and industrial fermentations. Genome-scale analysis of the phylogenetic relationships and predicted functions was conducted on 44 Acetobacteraceae isolates, including newly sequenced genomes from 18 isolates from wild and laboratory Drosophila. Isolates from the external environment and Drosophila could not be assigned to distinct phylogenetic groups, nor are their genomes enriched for any different sets of genes or category of predicted gene functions. In contrast, analysis of bacteria from laboratory Drosophila showed they were genetically distinct in their universal capacity to degrade uric acid (a major nitrogenous waste product of Drosophila) and absence of flagellar motility, while these traits vary among wild Drosophila isolates. Analysis of the competitive fitness of Acetobacter discordant for these traits revealed a significant fitness deficit for bacteria that cannot degrade uric acid in culture with Drosophila. We propose that, for wild populations, frequent cycling of Acetobacter between Drosophila and the external environment prevents genetic differentiation by maintaining selection for traits adaptive in both the gut and external habitats. However, laboratory isolates bear the signs of adaptation to persistent association with the Drosophila host under tightly defined environmental conditions. [ABSTRACT FROM AUTHOR]

Many aspects of animal ecology and physiology are influenced by the microbial communities within them. The underlying forces contributing to the assembly and diversity of gut microbiotas include chance events, host-based selection and interactions among microorganisms within these communities. We surveyed 215 wild individuals from four sympatric species of Drosophila that share a common diet of decaying mushrooms. Their microbiotas consistently contained abundant bacteria that were undetectable or at low abundance in their diet. Despite their deep phylogenetic divergence, all species had similar microbiotas, thus failing to support predictions of the phylosymbiosis hypothesis. Communities within flies were not random assemblages drawn from a common pool; instead, many bacterial operational taxonomic units ( OTUs) were overrepresented or underrepresented relative to the neutral expectations, and OTUs exhibited checkerboard distributions among flies. These results suggest that selective factors play an important role in shaping the gut community structure of these flies. [ABSTRACT FROM AUTHOR]

Microbial abundance and diversity of different life stages (fourth instar larvae, pupae and adults) of the diamondback moth, Plutella xylostella L., collected from field and reared in laboratory, were investigated using bacteria culture-dependent method and PCR-DGGE analysis based on the sequence of bacteria 16S rRNA V3 region gene. A large quantity of bacteria was found in all life stages of P. xylostella. Field population had higher quantity of bacteria than laboratory population, and larval gut had higher quantity than pupae and adults. Culturable bacteria differed in different life stages of P. xylostella. Twenty-five different bacterial strains were identified in total, among them 20 strains were presented in larval gut, only 8 strains in pupae and 14 strains in adults were detected. Firmicutes bacteria, Bacillus sp., were the most dominant species in every life stage. 15 distinct bands were obtained from DGGE electrophoresis gel. The sequences blasted in GenBank database showed these bacteria belonged to six different genera. Phylogenetic analysis showed the sequences of the bacteria belonged to the Actinobacteri, Proteobacteria and Firmicutes. Serratia sp. in Proteobacteria was the most abundant species in larval gut. In pupae, unculturable bacteria were the most dominant species, and unculturable bacteria and Serratia sp. were the most dominant species in adults. Our study suggested that a combination of molecular and traditional culturing methods can be effectively used to analyze and to determine the diversity of gut microflora. These known bacteria may play important roles in development of P. xylostella. [ABSTRACT FROM AUTHOR]

Abstract: In Focus: Mushegian, A. A., Walser, J. ‐C., Sullam, K. E., & Ebert, D. ( 2018). The microbiota of diapause: How host–microbe associations are formed after dormancy in an aquatic crustacean. Journal of Animal Ecology, 87, 400– 413. https://doi.org/10.1111/1365-2656.12709. All animals are colonized by micro‐organisms, most of which are benign or beneficial. Where do these micro‐organisms come from? Theory predicts that micro‐organisms which are transmitted vertically from parent to offspring are especially likely to be beneficial to the host, while horizontally acquired micro‐organisms are opportunistic and more variable in their impact on host performance. In this issue, Mushegian et al. ( ) investigate the source of bacteria that are required for the growth and development of Daphnia water fleas to reproductive adults. They find that, although vertically transmitted bacteria can occur in the capsule enclosing the Daphnia eggs, the micro‐organisms that promote Daphnia performance are associated with the external surface of the capsule and are of likely environmental origin. This mode of transmission may be adaptive for Daphnia because, linked to the longevity and capacity for long‐distance dispersal of these eggs, the environmental circumstances encountered by parent and offspring may be different; with the implication, the parental micro‐organisms may not be optimal for the offspring. This study demonstrates that, although some animals require symbioses with specific coevolved, vertically transmitted microbial symbionts, other animals have evolved dependence on taxonomically variable micro‐organisms of environmental origin. [ABSTRACT FROM AUTHOR]

Chemical ecology is a mechanistic approach to understanding the causes and consequences of species interactions, distribution, abundance, and diversity. The promise of chemical ecology stems from its potential to provide causal mechanisms that further our understanding of ecological interactions and allow us to more effectively manipulate managed systems. Founded on the notion that all organisms use endogenous hormones and chemical compounds that mediate interactions, chemical ecology has flourished over the past 50 years since its origin. In this essay we highlight the breadth of chemical ecology, from its historical focus on pheromonal communication, plant-insect interactions, and coevolution to frontier themes including community and ecosystem effects of chemically mediated species interactions. Emerging approaches including the -omics, phylogenetic ecology, the form and function of microbiomes, and network analysis, as well as emerging challenges (e.g., sustainable agriculture and public health) are guiding current growth of this field. Nonetheless, the directions and approaches we advocate for the future are grounded in classic ecological theories and hypotheses that continue to motivate our broader discipline. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the possibility that TP53 mRNA is variably expressed in chronic lymphocytic leukaemia (CLL) and that under-expression is associated with TP53 dysfunction and adverse outcome. Although TP53 mRNA levels did indeed vary among the 104 CLL samples examined, this variability resulted primarily from over-expression of TP53 mRNA in 18 samples, all of which lacked TP53 deletion/mutation. These patients had higher lymphocyte counts and shorter overall and treatment-free survival times compared to cases with low TP53 mRNA expression and no TP53 deletion/mutation. Furthermore, TP53 mRNA levels did not correlate with levels of TP53 protein or its transcriptional target CDKN1A. We speculated that the adverse outcome associated with TP53 mRNA over-expression might reflect variation in levels of MIR15A and MIR16-1, which are encoded on chromosome 13q14 and target TP53 and some oncogenes including BCL2. In keeping with our hypothesis, 13q14 copy number and levels of MIR15A/MIR16-1 correlated positively with one another but negatively with levels of TP53 mRNA and BCL2 mRNA. Our findings support a model in which loss of MIR15A/MIR16-1 at chromosome 13q14 results in adverse outcome due to de-repression of oncogenes such as BCL2, and up-regulation of TP53 mRNA as a bystander effect. [ABSTRACT FROM AUTHOR]

The resident microbiota of animals represents an important contribution to the global microbial diversity, but it is poorly known in many animals. This study investigated the bacterial diversity in plant phloem-sap-feeding whiteflies, aphids and psyllids by pyrosequencing bacterial 16 S rRNA gene amplicons. After correction for sequencing error, just 3-7 bacterial operational taxonomic units were recovered from each insect sample sequenced to sufficient depth for saturation of rarefaction curves. Most samples were dominated by primary and secondary symbionts, which are localized to insect cells or the body cavity, indicative of a dearth of bacterial colonists of the gut lumen. Diversity indices of the bacterial communities (Shannon's index: 0.40-1.46, Simpson's index: 0.15-0.74) did not differ significantly between laboratory and field samples of the phloem-feeding insects, but were significantly lower than in drosophilid flies quantified by the same methods. Both the low bacterial content of the phloem sap diet and biological processes in the insect may contribute to the apparently low bacterial diversity in these phloem-feeding insects. [ABSTRACT FROM AUTHOR]

In chronic lymphocytic leukaemia ( CLL), TP53 mutation and deletion are strongly associated with one another and with adverse clinical outcome. Mutant TP53 protein typically accumulates to high levels and has been reported to have transcriptional regulatory activity distinct from that of wild-type TP53. To investigate whether such an effect is relevant to CLL, carefully balanced primary CLL samples with or without TP53 mutation/deletion were compared for their gene expression profiles using high-density DNA microarrays. Ninety-six and eight differentially expressed genes were identified, respectively, using two alternative statistical approaches with different stringencies. None of the differentially expressed genes were known to be regulated by mutant TP53, and only four of the 67 under-expressed genes were known transcriptional targets of wild-type TP53. Significantly, both approaches showed that gene under-expression was the dominant feature of TP53-mutant CLL samples. Furthermore, a disproportionate number of the under-expressed genes were located on chromosome 17p, the most significant being TP53 itself. Together, these results indicate that any transcriptional regulatory effects of mutant TP53 in CLL cells are overshadowed by the under-expression of co-deleted TP53 and other genes on chromosome 17p. Our findings have implications for emerging therapeutic strategies that target mutant TP53. [ABSTRACT FROM AUTHOR]

Summary [ABSTRACT FROM AUTHOR]

Arthropods, including insects, are unique among animals in that they cannot synthesize sterols, including cholesterol, de novo. Some phytophagous insects (e.g. caterpillars, grasshoppers) generate tissue cholesterol by metabolizing plant phytosterols. Currently, little is known about sterols in plant phloem sap, and their significance to the nutritional physiology and ecology of phloem-feeding insects. The sterol profiles of leaves from two plant species, Chinese cabbage and tobacco, were dominated by the phytosterols sitosterol and stigmasterol, respectively. In contrast, the principle sterol in the phloem sap of both plants was cholesterol, which is traditionally considered an animal sterol. Cholesterol was also the most abundant sterol in the carcass and honeydew of Myzus persicae aphids feeding on these plants. The effect of sterol structure on M. persicae was investigated using modified tobacco plants that contained high levels of atypical steroids, specifically ketone-steroids. Aphids reared on the modified tobacco plants had a high atypical steroid content, severely reduced reproduction and high mortality. Our data indicate that the total sterol composition of plants is not necessarily representative of the sterol profile available to phloem-feeding insects, and that the sterol utilization patterns of phloem-feeding insects may differ from chewing insect herbivores utilizing the same plant. Atypical steroids are naturally at insufficient concentrations for significant deleterious effects on insect herbivores, and possible reasons why plants apparently do not use them as defensive compounds are considered. [ABSTRACT FROM AUTHOR]

Contents Many symbioses are widespread, abundant, and evolutionarily persistent. This is despite unambiguous evidence for conflict between the partners and the existence of cheats that use benefits derived from their partners while providing reduced or no services in return. Evidence from a diversity of associations suggests that symbioses are robust to cheating in several ways. Some symbioses persist despite conflict and cheating because of the selective advantage of cost-free interactions (also known as byproduct mutualistic interactions), which incur no conflict. There is also evidence for the suppression of cheating by sanctions imposed by partners in some symbioses, and vertical transmission has been shown experimentally to promote traits that enhance partner performance. It is argued that these processes contribute to the apparent rarity of evolutionary transitions from symbiosis to parasitism. There is strong phylogenetic evidence for the evolutionary reversion of various symbiotic organisms to free-living lifestyles, but at least some of these transitions can be attributed to selection pressures other than within-symbiosis conflict. The principal conclusion is that, although conflict is common in symbioses, it is generally managed and contained. [ABSTRACT FROM AUTHOR]

Bleaching of corals by loss of symbiotic dinoflagellate algae and/or photosynthetic pigments is commonly triggered by elevated temperatures coupled with high irradiance, and is a first-order threat to coral reef communities. In this study, a high-resolution high-performance liquid chromatography method integrated with mass spectrometry was applied to obtain the first definitive identification of chlorophyll and carotenoid pigments of three clades of symbiotic dinoflagellate algae ( Symbiodinium) in corals, and their response to experimentally elevated temperature and irradiance. The carotenoids peridinin, dinoxanthin, diadinoxanthin (Dn), diatoxanthin (Dt) and β-carotene were detected, together with chlorophylls a and c2, and phaeophytin a, in all three algal clades in unstressed corals. On exposure to elevated temperature and irradiance, three coral species ( Montastrea franksi and Favia fragum with clade B algae, and Montastrea cavernosa with clade C) bleached by loss of 50–80% of their algal cells, with no significant impact to chlorophyll a or c2, or peridinin in retained algal cells. One species ( Agaricia sp. with clade C) showed no significant reduction in algal cells at elevated temperature and irradiance, but lost substantial amounts of chlorophyll a and carotenoid pigments, presumably through photo-oxidative processes. Two coral species ( Porites astreoides and Porites porites both bearing clade A algae) did not bleach. The impact of elevated temperature and irradiance on the levels of the photoprotective xanthophylls (Dn + Dt) and β-carotene varied among the corals, both in pool size and xanthophyll cycling, and was not correlated to coral bleaching resistance. [ABSTRACT FROM AUTHOR]

1. Pea aphids, Acyrthosiphon pisum, harbour a range of facultative accessory bacteria (secondary symbionts), including those informally known as PASS (R-type), PAR, PABS (T-type), and PAUS (U-type). 2. To explore the relationship between possession of these bacteria and ecologically important traits of A. pisum, correlations between the accessory bacteria found in 47 parthenogenetic clones of A. pisum and the host plant on which each clone was collected and its susceptibility to natural enemies were surveyed. 3. The bacterial complement varied with plant of collection. PAUS (U) was present in all of 12 clones affiliated to Trifolium but was otherwise rare, while PABS (T) and PASS (R) occurred at significantly higher frequency in clones from Lotus and Vicia, respectively, than clones from other plants. 4. Possession of PABS (T) was associated strongly with resistance to the parasitoid Aphidius eadyi and weakly with resistance to Aphidius ervi. Aphids carrying PAUS (U) were more resistant to the fungal pathogen Pandora ( Erynia) neoaphidis, although this correlation was complicated by a strong association with host-plant use. [ABSTRACT FROM AUTHOR]