Phytoseiid mites from tropical fruit trees in Bahia State,Brazil (Acari,Phytoseiidae)

The cultivation of tropical fruit trees has grown considerably in the state of Bahia, northeastern Brazil. Some of these have been severely attacked by phytophagous mites, which are usually controlled by the use of chemical pesticides. However, there is today a growing interest for the adoption of less aggressive measures of pest control, as for example the use of predatory mites. Most of the plant-inhabiting predatory mites belong to the family Phytoseiidae. The objective of this paper is to report the phytoseiid species found in an intensive survey conducted on cultivated tropical fruit trees in fifteen localities of the southern coast of Bahia. Measurements of relevant morphological characters are provided for each species, to complement the understanding of the morphological variation of these species. Twenty-nine species of sixteen genera were identified. A key was elaborated to assist in the separation of these species. Fifteen species are reported for the first time in the state, raising to sixty-six the number of species of this family now known from Bahia. Seventy-two percent of the species collected belong to Amblyseiinae, followed by Typhlodrominae (21%) and Phytoseiinae (7%). The most diverse genus was Amblyseius. Amblyseius operculatus De Leon was the most frequent and abundant species. Studies should be conducted to evaluate the possible role of the most common predators as control agents of the phytophagous mites co-occurring with them.     

Correlation between Olfactory Responses, Dispersal Tendencies, and Life-history Traits of the Predatory Mite Neoseiulus Womersleyi (Acari: Phytoseiidae) of Eight Local Populations

To investigate the relationship between foraging behavior and life-history traits of the predatory mite Neoseiulus womersleyi, the olfactory responses, dispersal ratios from a prey patch, predation rates, fecundity, and developmental times in eight local populations of N. womersleyi were investigated. Significant differences among local populations were found in all these traits except fecundity. None of the life-history traits correlated with foraging behavior. A significant positive correlation was found only between the olfactory response and the dispersal ratio. These results suggested that predatory mites with low olfactory responses would stay in a prey patch longer than predatory mites with high olfactory responses.     

Life-history of predatory mites Neoseiulus californicus and Phytoseiulus persimilis (Acari: Phytoseiidae) on four spider mite species as prey, with special reference to Tetranychus evansi (Acari: Tetranychidae)

The commercially available strains of Phytoseiulus persimilis Athias-Henriot, the biological control agent of Tetranychus urticae Koch, perform poorly in the Western Mediterranean, probably because they are not well adapted to local climatic conditions. For that reason, efforts are being focused on the development of a biological control programme using native phytoseiid mites. Four species of red spider mites can be found in vegetable crops in eastern Spain: T. urticae, Tetranychus turkestani Ugarov and Nikolski, Tetranychus ludeni Zacher and the recently introduced Tetranychus evansi Baker and Pritchard. To evaluate their potential role as biological control agents, the present study evaluates the life-history of local populations of Neoseiulus californicus (McGregor) and P. persimilis when fed on T. urticae, T. turkestani, T. evansi, and T. ludeni in the laboratory. Results indicate that N. californicus and P. persimilis are able to feed and complete their development on the four tested red spider mite species. The predators may exhibit a particularly high capacity for population increase when fed on T. urticae, T. turkestani, and T. ludeni, thus may be able to provide effective control of these species in the field. When fed T. evansi, however, predator performance was poor; significant increase in development and preoviposition times, and a reduction in oviposition period and fecundity were recorded. The resultant low capacity for population growth suggests poor ability of the two tested predators to suppress T. evansi populations on commercial crops. It is unlikely therefore that P. persimilis and N. californicus, now being widely used to control T. urticae in greenhouse crops in Central Europe, will be able to halt any spread of T. evansi to greenhouse crops in temperate areas.     

Evaluation of the predatory mite <Emphasis Type="Italic">Phytoseiulus macropilis</Emphasis> (Acari: Phytoseiidae) as a biological control agent of the two-spotted spider mite on strawberry plants under greenhouse conditions

The predatory mite Phytoseiulus macropilis is a potential biological control agent of the two-spotted spider mite (TSSM) Tetranychus urticae on strawberry plants. Its ability to control TSSM was recently assessed under laboratory conditions, but its ability to locate and control TSSM under greenhouse conditions has not been tested so far. We evaluated whether P. macropilis is able to control TSSM on strawberry plants and to locate strawberry plants infested with TSSM under greenhouse conditions. Additionally, we tested, in an olfactometer, whether odours play a role in prey-finding by P. macropilis. The predatory mite P. macropilis required about 20 days to achive reduction of the TSSM population on strawberry plants initially infested with 100 TSSM females per plant. TSSM-infested plants attract an average of 27.5 ± 1.0% of the predators recaptured per plant and uninfested plants attracted only 5.8 ± 1.0% per plant. The predatory mites were able to suppress TSSM populations on a single strawberry plant and were able to use odours from TSSM-infested strawberry plants to locate prey in both olfactometer and arena experiments. Hence, it is concluded that P. macropilis can locate and reduce TSSM population on strawberry plants under greenhouse conditions.     

Altered host plant preference of Tetranychus urticae and prey preference of its predator Phytoseiulus persimilis (Acari: Tetranychidae, Phytoseiidae) on transgenic Cry3Bb-eggplants

The behavior of the two-spotted spider mite, Tetranychus urticae Koch and the predatory mite Phytoseiulus persimilis A.-H. was investigated in laboratory experiments with transgenic Bt-eggplants, Solanum melongena L., producing the Cry3Bb toxin and corresponding isogenic, non-transformed eggplants. In bitrophic experiments, dual-choice disc tests were conducted to reveal the effects of transgenic eggplants on host plant preference of T. urticae. Adult spider mite females were individually placed on leaf discs (2 cm diameter) and were observed during five days. Females occurred significantly more frequently on transgenic halves on which also significantly more T. urticae eggs were found. The effects of a Cry3Bb-eggplant fed prey on the feeding preference of P. persimilis were investigated in tritrophic experiments. Sixteen spider mite females, eight of which had been taken from transgenic and eight from isogenic eggplants, were offered to well-fed females of P. persimilis and numbers of respective spider mites consumed were registered 12 h later when the predators were offered new spider mites again. This procedure was repeated six times. The results revealed that predatory mites consumed significantly less Bt-fed spider mites than prey that had been raised on control eggplants. These results indicate that eggplants expressing the Cry3Bb toxin for resistance against the Colorado potato beetle are more preferred by spider mites but are less preferred by their predator P. persimilis. Possible consequences of these findings for biological control of spider mites on eggplants are discussed.     

Feeding History Affects the Response of the Predatory Mite Typhlodromus Kerkirae (Acari: Phytoseiidae) to Volatiles of Plants Infested with Spider Mites

The response of adult females of the predatory mite Typhlodromus kerkirae (Acari: Phytoseiidae) to volatiles emitted from bean leaves infested with Tetranychus urticae (Acari: Tetranychidae) or from leaves of Oxalis corniculata infested with Petrobia harti (Acari: Tetranychidae) was studied in the laboratory using a Y-tube olfactometer. Typhlodromus kerkirae females reared from larvae through to adults on T. urticae and pollen of Vicia faba responded to volatiles of bean leaves infested with T. urticae, either when they had a choice between infested and non-infested bean leaves or between bean leaves infested with T. urticae and O. corniculata leaves infested with P. harti. However, they did not respond when they had been reared only on the carotenoid-deficient pollen of V. faba. Female T. kerkirae that had been reared from larva to the tenth day of adult life on T. urticae and subsequently fed for 1 week on V. faba pollen did not respond to volatiles of bean leaves infested with T. urticae. In contrast, those that had been reared on V. faba pollen to the tenth day of adult life and subsequently fed for 1 week on T. urticae responded to volatiles of infested bean leaves.     

Evaluation of astigmatid mites as factitious food for rearing four predaceous phytoseiid mites (Acari: Astigmatina; Phytoseiidae)

Phytoseiids are possibly the most important mites used in biological control and are usually produced using a tritrophic system that, although efficient, is expensive and laborious. Mites of the cohort Astigmatina (Sarcoptiformes) have been used as factitious prey in the mass rearing of phytoseiids and may allow a much simpler production system. This research evaluated the potential of ten Astigmatina species to serve as factitious food sources for Euseius concordis (Chant), Iphiseiodes zuluagai Denmark and Muma, Neoseiulus barkeri Hughes and Neoseiulus californicus McGregor, all phytoseiid species commonly found in different countries. The high fecundity and survival rates obtained suggest that Thyreophagus n. sp. is a suitable prey for rearing N. barkeri and that Austroglycyphagus lukoschusi (Fain) and Blomia tropicalis is suitable for rearing N. californicus. Oviposition by E. concordis was negligible, but survivorship was high on most prey species, suggesting that these species may be useful for maintenance of the predator. I. zuluagai had low fecundity and survival on all the astigmatid species evaluated and none were suitable for its rearing.     

The Effects of Prey Patchiness, Predator Aggregation, and Mutual Interference on the Functional Response of Phytoseiulus persimilis Feeding on Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae)

The spatial distributions of two-spotted spider mites Tetranychus urticae and their natural enemy, the phytoseiid predator Phytoseiulus persimilis, were studied on six full-grown cucumber plants. Both mite species were very patchily distributed and P. persimilis tended to aggregate on leaves with abundant prey. The effects of non-homogenous distributions and degree of spatial overlap between prey and predators on the per capita predation rate were studied by means of a stage-specific predation model that averages the predation rates over all the local populations inhabiting the individual leaves. The empirical predation rates were compared with predictions assuming random predator search and/or an even distribution of prey. The analysis clearly shows that the ability of the predators to search non-randomly increases their predation rate. On the other hand, the prey may gain if it adopts a more even distribution when its density is low and a more patchy distribution when density increases. Mutual interference between searching predators reduces the predation rate, but the effect is negligible. The stage-specific functional response model was compared with two simpler models without explicit stage structure. Both unstructured models yielded predictions that were quite similar to those of the stage-structured model.     

Interactions of two natural enemies of Tetranychus evansi, the fungal pathogen Neozygites floridana (Zygomycetes: Entomophthorales) and the predatory mite, Phytoseiulus longipes (Acari: Phytoseiidae)

Tetranychus evansi is an exotic pest of Solanaceous crops in Africa discovered in Zimbabwe in 1979. Two natural enemies, the predatory mite Phytoseiulus longipes and the fungal pathogen Neozygites floridana are important causes of mortality in T. evansi populations in Brazil. The first part of this study assessed the effects of N. floridana on predation and oviposition of P. longipes fed on N. floridana infected T. evansi and T. urticae. No N. floridana hyphal bodies were found in P. longipes after this feeding, demonstrating that N. floridana is not pathogenic to P. longipes and does not affect its oviposition. The second part of the study investigated the time spent on searching for and consuming of eggs on leaf discs with and without N. floridana capilliconidia. Both the searching and the feeding time on the first egg were similar on leaf discs with and without capilliconidia. When P. longipes was offered the choice of feeding on eggs on leaf discs with or without capilliconidia, the numbers of eggs consumed were not different. The only N. floridana effect observed on P. longipes was reduced egg predation. In addition, increased time spent grooming on leaf discs with capilliconidia was observed. P. longipes was efficient in removing most capilliconidia attached to the body through self-grooming behavior. This suggests that although the predator did not avoid areas with capilliconidia, it detected and removed most capilliconidia attached to the body. Increased grooming may account for the lower egg predation rates.     

Olfactory response of Typhlodromus pyri (Acari: Phytoseiidae) to synthetic methyl salicylate in laboratory bioassays

The herbivore‐induced plant volatile (HIPV) methyl salicylate (MeSA) is widely present in the chemical profile of several plant species and is known to attract natural enemies, including predatory mites. In this study, the response of Typhlodromus pyri, a key predator of pest mites in west coast vineyards, to synthetically produced MeSA was tested using a Y‐tube olfactometer in laboratory bioassays. Six doses ranging from 0.002 to 200 μg of MeSA diluted in 0.1 ml hexane were tested. Significantly higher proportions of T. pyri preferred MeSA at doses 0.02, 0.2 and 20 μg. No differences in response to MeSA were detected at the highest (200 μg), intermediate (2 μg) and lowest (0.002 μg) doses. Mite response to MeSA was a function of dose when fitting polynomial and logistic regression models using dose and square of the log dose prediction factors. Results indicate that synthetic MeSA may be applied to attract predatory arthropod populations in vineyards to enhance biological control of pest mites.     

Infochemical-Mediated Niche Use by the Predatory Mites Typhlodromalus manihoti and T. aripo (Acari: Phytoseiidae)

In Africa, Typhlodromalus manihoti and T. aripo, two introduced predators of the cassava green mite Mononychellus tanajoa, occupy different parts of cassava foliage. In the present study, niche use by these two predators, as mediated by prey-induced infochemicals, was investigated. In response to prey feeding damage, cassava plant parts emit volatile blends, that attract phytoseiidae predators. When given a choice between old cassava leaves infested with M. tanajoa and either apices or young cassava leaves infested with M. tanajoa, T. aripo displayed a marked preference for odors emitted from either infested apices or infested young leaves over infested old leaves but showed no preference for odors from apices versus young leaves, all infested with M. tanajoa. Typhlodromalus manihoti did not discriminate between volatiles from the three infested cassava plant parts. Our data show that T. aripo uses differences in volatile blends released by infested cassava plant parts and restricts its fundamental niche to a realized niche, which enables coexistence with its competitor T. manihoti.     

Different colonization patterns of phytophagous and predatory mites (Acari: Tetranychidae, Phytoseiidae) on three grape varieties: a case study

In a vineyard having three varieties of grape (Merlot, Trebbiano and Garganega) differently colonized by two phytoseiid species,Typhlodromus pyri Scheuten andAmblyseius andersoni (Chant), the dynamics of mite populations were monitored over 5 years (1989–1993) in order to study their colonization, interspecific competition and the control of spider mites, i.e.Panonychus ulmi (Koch). These aspects were also investigated by releasingT. pyri, A. andersoni andAmblyseius aberrans (Oudemans) on some of the above varieties. In most of the experimental years (1989–1992), selective pesticides were used in order to allow a successful release of phytoseiids, in particularA. aberrans. The use of non-selective insecticides was re-established during 1993 in order to test its effect on the new mite communities originating from 1989 onwards. In the first years of the experiments an apparent relationship between grape variety and phytoseiid species was observed: in the control plots,A. andersoni occurred on Merlot whereT. pyri was rare, while the latter species was largely dominant overA. andersoni on Trebbiano and Garganega.Panonychus ulmi populations reached moderate levels only on Merlot and in the first part of experiments. The variety-phytoseiid species relationship was temporary as, at the end of experiments,T. pyri was completely dominant on all varieties. This new situation started when prey occurrence and interspecific competition decreased in importance. The moderate success of theT. pyri release on Merlot contrasts with the results of previous experiments. Two factors could be involved in this phenomenon: low interspecific competition by phytoseiids and predation by macropredators.Amblyseius aberrans was able to displaceA. andersoni andT. pyri on grape varieties where the two species were more abundant and reached higher population densities on varieties with pubescent leaf undersurfaces. In the first experimental year, spider mite densities were reduced more effectively inA. aberrans release plots than in the control or inT. pyri release plots. One year later,P. ulmi reached lower levels in the release treatments than in the control.Typhlodromus pyri andA. aberrans persisted in conditions of prey scarcity. The high competitivity ofA. aberrans over the remaining two phytoseiid species constitutes a major factor in selecting predatory species for inoculative releases in vineyards.     

Population dynamics of phytophagous and predatory mites (Acari: Tetranychidae, Eriophyidae, Phytoseiidae) on bamboo plants in Fujian, China

The seasonal cycle and population dynamics of Schizotetranychus nanjingensis Ma and Yuan, Aponychus corpuzae Rimando (Tetranychidae), Aculus bambusae Kuang (Eriophyidae) and their natural enemy Typhlodromus bambusae Ehara (Phytoseiidae) were studied during 1996–1998 in moso bamboo forests in Nanping, Fujian, China. Damage to bamboo leaves was often caused by mixed populations of the three phytophagous species, which displayed different seasonal dynamics: S. nanjingensis fed actively and reproduced in May and from late July to late October (aestivating from June to mid July), Ap. corpuzae was active and reproduced from mid July to late November, and Ac. bambusae from July to next February. During Spring S. nanjingensis was the dominant species with the greatest niche width, but in Summer Ac. bambusae and Ap. corpuzae became dominant and had greater niche widths. In Autumn, Ac. bambusae decreased but both S. nanjingensis and Ap. corpuzae mites increased and the latter became dominant. In winter all species decreased sharply in number. The two spider mite species (S. nanjingensis and Ap. corpuzae) had high niche overlaps in all four seasons. Niche overlaps between the eriophyid Ac. bambusae and the two spider mites were similarly high except during the spring when Ac. bambusae was absent. The predatory mite (T. bambusae) had higher niche overlap with Ap. corpuzae than with others during Autumn and Winter, but during Spring and Summer niche overlap was higher with S. nanjingensis.     

Effects of mating rates on oviposition,sex ratio and longevity in a predatory mite <Emphasis Type="Italic">Neoseiulus cucumeris</Emphasis> (Acari: Phytoseiidae)

Two aspects of mating effects on the fecundity, sex ratio and longevity of Neoseiulus cucumeris (Acari: Phytoseiidae) were examined in laboratory experiments: (1) females mated by one, two or three different males (unmated and 3 days old) at 5-day intervals, and (2) females mated by males with different age/mating status (number of females mated previously by the male). Females allowed to mate with a second or third male at 5-day intervals produced 39 eggs on average, but those mated with a single male produced 28 eggs on average. Matings with additional males 5 or 10 days after the first male increased the duration of the oviposition period of these females by 5–7 days and at the same time reduced the post-oviposition period by about 10 days. Overall, females with additional matings by one or two different males at 5-day intervals survived a few days shorter than females without additional males. Mating with a different female each day, a male of N. cucumeris could mate with 5–8 females, which produced a total of 85–116 eggs: females mated with a male during days 1 and 2 in its adulthood and with a male of the last 2 days of life (days 7 and 8) produced about half as many eggs as females mated with a male during 3–6 days of its adulthood. Females mated with males that are too young or too old had a shorter oviposition period and a longer post-oviposition period and longevity than females mated with middle-aged males. In both experiments, rates of oviposition remained similar in females with high or low fecundity. This indicates that in both cases, the increased fecundity is due to the extension of the oviposition period through additional sperm supplied by the second male and or third male (in experiment 1) or more sperm by males not too young nor too old (experiment 2).     

Genetic Variation in Foraging Traits and Life-History Traits of the Predatory Mite Neoseiulus womersleyi (Acari: Phytoseiidae) among Isofemale Lines

The predatory mite Neoseiulus womersleyi shows a significant correlation between its olfactory response and dispersal tendency in different geographical populations. This study investigated the genetic background of the relationship using isofemale lines. Y-tube olfactometer tests confirmed that there was a genetic component in predator response to herbivore-induced plant volatiles. Wind tunnel tests in the absence of the herbivore-induced plant volatiles revealed that the dispersal tendencies of N. womersleyi exhibited genetic variation among isofemale lines, and other experiments revealed the existence of significant differences in prey consumption rate, fecundity, and developmental time. However, there was no genetic correlation between behavioral traits (olfactory response, innate dispersal) and the other traits, suggesting that the positive correlation between the behavioral traits was not caused by genetic factors.     

Risk assessment of an exotic biocontrol agent: Phytoseiulus persimilis (Acari: Phytoseiidae) does not establish in rainforest in southeast Queensland

Abstract The Chilean predatory mite, Phytoseiulus persimilis Athias-Henriot, appeared in Australia in 1978 soon after being introduced into New Zealand as a specialized biological control agent of spider mites. It is known to be naturalized in agricultural habitats in southeast Queensland, Australia, although nothing is known about its distribution in native ecosystems. In order to determine whether P. persimilis is able to invade subtropical rainforest, we placed potted bean plants infested with its preferred prey, the two-spotted mite (Tetranychus urticae C.L. Koch), at 50 m intervals for 200 m on either side of the rainforest-field ecotone at four sites in southeast Queensland. Two, 4 and 6 weeks after placement, five leaves were sampled from each pot and any phytoseiid mites present were identified. The initial experiment took place in the spring and was repeated in summer and in autumn of 1997. At all four sites and in all three seasons P. persimilis rapidly colonized all of the pots in fields. In the rainforest, however, some pots were never colonized and significant populations of the predator developed only in the summer, and then only at the first stations, 50 m into the forest. These results suggest that even when its preferred prey is present, subtropical rainforest is not an appropriate habitat for P. persimilis. In addition, we reviewed extensive collections of phytoseiid mites from native forests and synanthropic habitats in Australia and found P. persimilis records only from fields, glasshouses, gardens, weeds, roadsides and similar disturbed habitats dominated by introduced plants, again suggesting that this biocontrol agent is not a rainforest invader.     

Compatibility of Orius laevigatus Fieber (Hemiptera: Anthocoridae) with Neoseiulus Amblyseius cucumeris Oudemans (Acari: Phytoseiidae) and Iphiseius Amblyseius) degenerans Berlese (Acari: Phytoseiidae) in the biocontrol of Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)

The compatibility of Orius laevigatus Fieber with Neoseiulus (Amblyseius) cucumeris Oudemans as predators of Frankliniella occidentalis Pergande was assessed in 24 h tests on French bean leaf discs. At varying densities of N. cucumeris and F. occidentalis in the presence of a single female O. laevigatus, it was found that O. laevigatus fed on both other organisms to a similar extent, thus raising questions as to the suitability of this combination of predators in the biocontrol of F. occidentalis. In similar trials assessing the compatibility of O. laevigatus with Iphiseius (Amblyseius) degenerans Berlese, O. laevigatus preyed on F. occidentalis to a greater extent than on I. degenerans. It is hypothesized that O. laevigatus and I. degenerans could be used simultaneously in the biocontrol of F. occidentalis with minimal interference between them.     

Rainforest habitat resistance to the migration of Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in south-eastern Queensland

Abstract  This paper tests the hypothesis that habitat differences affect the migratory ability of the Chilean predatory mite, Phytoseiulus persimilis , an introduced biological control agent of the spider mite, Tetranychus urticae . It is suggested that habitat resistance accounts for the species' inability to invade rainforests in south-eastern Queensland, Australia. Like its prey, P. persimilis migrates to distant plants on air currents. To test our hypothesis, populations of the Chilean predatory mite were established on potted bean plants in both remnant rainforest and adjacent open fields, and their migration monitored using sticky traps. Overall it was found that prey populations on leaves were similar in both habitats, but those of predators were about 20% lower in rainforest. However, the numbers of both predators and prey caught on sticky traps in rainforest were about 6% and 25%, respectively, of those caught in open fields, indicating a strongly reduced rate of aerial migration in the forest. The number of P. persimilis caught on the sticky traps increased with increasing populations of predators on foliage. Thus, dense vegetation inhibits the movement of air currents and inhibits colonisation by both predators and, to a lesser extent, spider mites. These results suggest that the inhibition of aerial migration is one reason for lower numbers of P. persimilis in forest habitats, both because its own vagility is restricted, and because its prey is less able to disperse.     

Biology and efficacy of the predatory mite, Amblyseius longispinosus (Evans) (Acari, Phytoseiidae) as a biological control agent of Eotetranychus cendanai Rimando (Acari, Tetranychidae)

Egg, larval, protonymphal and deutonymphal stages of Amblyseius longispinosus (Evans) that fed on Eotetranychus cendanai , required 2.02 ± 0.13, 0.57 ± 0.17, 1.07 ± 0.31 and 1.16 ± 0.53 days, respectively. The total developmental time was 4.79 ± 0.61 days. Female longevity averaged 14.61 ± 2.88 days in which 19.54 ± 6.36 eggs/female or 1.33 ± 0.29 eggs/female per day were laid. The highest predation rate was detected at a prey density of 40–50. Amblyseius longispinosus could be employed as the biological control agent of E. cendanai both in laboratory and greenhouse conditions at the predator : prey ratio of 1 : 30 to 1 : 50.     

Microbial diversity in the predatory mite Metaseiulus occidentalis (Acari: Phytoseiidae) and its prey, Tetranychus urticae (Acari: Tetranychidae)

Microorganisms associated with the predatory mite Metaseiulus (=Typhlodromus or Galendromus) occidentalis (Nesbitt) and its prey, the two-spotted spider mite Tetranychus urticae (Koch), were assessed using a high-fidelity polymerase chain reaction (PCR) protocol and primers designed to identify Eubacteria, Archaeabacteria, iridoviruses, Helicosporidia, Cytophaga-like microorganisms, Wolbachia and its bacteriophage WO, fungi and yeast-like organisms. Sequences from four bacterial species related to Wolbachia (α-Proteobacteria), Cardinium, Bacteroidetes, and Enterobacter (γ-Proteobacteria) were obtained from M. occidentalis, and three sequences related to Wolbachia, Rickettsia, and Caulobacter (α-Proteobacteria) were obtained from T. urticae. No nucleotide differences were detected between the 16S rRNA, wspA or wspB Wolbachia sequences obtained from M. occidentalis and T. urticae, which suggest that horizontal transfer of Wolbachia could have occurred. Southern blot analyses of genomic DNA from both M. occidentalis and T. urticae using wspA probes were negative, indicating that this Wolbachia sequence is not integrated into the nuclear genome of either species. Two of the T. urticae colonies tested contained the WO bacteriophage, but none of the six M. occidentalis populations were infected. New M. occidentalis-specific forward and reverse 16S rRNA primers based on the Wolbachia, Cardinium, Bacteroidetes, and Enterobacter sequences obtained were designed and used to amplify PCR products from each of two laboratory and four field-collected samples of M. occidentalis females and eggs, indicating that these infections are widespread. Likewise, species-specific primers for T. urticae were designed for the Wolbachia, Rickettsia, and Caulobacter sequences obtained and used to evaluate T. urticae from strawberries, wine grapes, hops, almonds, and cherries from California, Washington, and Florida; all were positive for Wolbachia and Caulobacter but two of the six were negative for Rickettsia. None of the M. occidentalis colonies tested were positive for the microsporidium Oligosporidium occidentalis, which previously had been associated with a pathogenic condition in some of our laboratory colonies. The Gainesville colonies of M. occidentalis and T. urticae were negative for iridovirus, Archaeabacteria, fungi, Helicosporidia, and yeast-like organisms. So far, Wolbachia is the only symbiont that is shared by this predator and its prey.