Uninfected Mites Research Articles

The symbiont Wolbachia alleviates pesticide susceptibility in the two-spotted spider mite Tetranychus urticae through enhanced host detoxification pathways.

The two-spotted spider mite (Tetranychus urticae) is one of the most well-known pesticide-resistant agricultural pests, with resistance often attributed to changes such as target-site mutations and detoxification activation. Recent studies show that pesticide resistance can also be influenced by symbionts, but their involvement in this process in spider mites remains uncertain. Here, we found that infection with Wolbachia, a well-known bacterial reproductive manipulator, significantly increased mite survival after exposure to the insecticides abamectin, cyflumetofen, and pyridaben. Wolbachia-infected (WI) mites showed higher expression of detoxification genes such as P450, glutathione-S-transferase (GST), ABC transporters, and carboxyl/cholinesterases. RNA interference experiments confirmed the role of the two above-mentioned detoxification genes, TuCYP392D2 and TuGSTd05, in pesticide resistance. Increased GST activities were also observed in abamectin-treated WI mites. In addition, when wild populations were treated with abamectin, WI mites generally showed better survival than uninfected mites. However, genetically homogeneous mites with different Wolbachia strains showed similar survival. Finally, abamectin treatment increased Wolbachia abundance without altering the mite's bacterial community. This finding highlights the role of Wolbachia in orchestrating pesticide resistance by modulating host detoxification. By unraveling the intricate interplay between symbionts and pesticide resistance, our study lays the groundwork for pioneering strategies to combat agricultural pests.

Pathogenesis and defense mechanism while Beauveria bassiana JEF-410 infects poultry red mite, Dermanyssus gallinae.

The poultry red mite, Dermanyssus gallinae (Mesostigmata: Dermanyssidae), is a major pest that causes great damage to chicken egg production. In one of our previous studies, the management of red mites using entomopathogenic fungi was evaluated, and the acaricidal fungus Beauveria bassiana JEF-410 was selected for further research. In this study, we tried to elucidate the pathogenesis of B. bassiana JEF-410 and the defense mechanisms of red mites at a transcriptome level. Red mites collected from a chicken farm were treated with B. bassiana JEF-410. When the mortality of infected red mites reached 50%, transcriptome analyses were performed to determine the interaction between B. bassiana JEF-410 and red mites. Uninfected red mites and non-infecting fungus served as controls. In B. bassiana JEF-410, up-regulated gene expression was observed in tryptophan metabolism and secondary metabolite biosynthesis pathways. Genes related to acetyl-CoA synthesis were up-regulated in tryptophan metabolism, suggesting that energy metabolism and stress management were strongly activated. Secondary metabolites associated with fungal up-regulated DEGs were related to the production of substances toxic to insects such as beauvericin and beauveriolide, efflux pump of metabolites, energy production, and resistance to stress. In red mites, physical and immune responses that strengthen the cuticle against fungal infection were highly up-regulated. From these gene expression analyses, we identified essential factors for fungal infection and subsequent defenses of red mites. These results will serve as a strong platform for explaining the interaction between B. bassiana JEF-410 and red mites in the stage of active infection.

Vertical Transmission of Salmonella enterica ser. Gallinarum in Dermanyssus gallinae by the Mean of the Baudruche-Based Artificial Feeding Device

The poultry red mite (PRM) Dermanyssus gallinae is well known for its vectorial role for pathogens, such as Salmonella enterica ser. Gallinarum, the causative agent of fowl typhoid. Here, we ascertained the vertical transmission of S. Gallinarum across the PRM life stages, combining the Baudruche-based in vitro feeding system and a PRM-fitting DNA extraction and detection method by qPCR. Small-sized pools (4–5 specimens) of adult mites, eggs, larvae, and protonymphs, as well as single eggs, were tested for S. Gallinarum. The pathogen was detected in 89% of adult mites, 5% of single eggs, 17% of pooled eggs, 9% of larvae, and 43% of protonymphs. Additionally, the feeding rate for infected and uninfected mites was similar, while differences in ovipositing and fecundity rate were observed. The method allowed to confirm the infection of mites through the bloodmeal and to strongly suggest the transmission of S. Gallinarum across the PRM life stages. Furthermore, it allows to avoid in vivo studies and it could be useful for further investigating the vectorial role of D. gallinae or other hematophagous arthropods for infectious agents.

Spider Mites Singly Infected With Either Wolbachia or Spiroplasma Have Reduced Thermal Tolerance.

Heritable symbionts play an essential role in many aspects of host ecology in a temperature-dependent manner. However, how temperature impacts the host and their interaction with endosymbionts remains largely unknown. Here, we investigated the impact of moderate (20°C) and high (30 and 35°C) temperatures on symbioses between the spider mite Tetranychus truncatus and two maternally inherited endosymbionts (Wolbachia and Spiroplasma). We found that the thermal tolerance of mites (as measured by survival after heat exposure) was lower for mites that were singly infected with either Wolbachia or Spiroplasma than it was for co-infected or uninfected mites. Although a relatively high temperature (30°C) is thought to promote bacterial replication, rearing at high temperature (35°C) resulted in losses of Wolbachia and particularly Spiroplasma. Exposing the mites to 20°C reduced the density and transmission of Spiroplasma but not Wolbachia. The four spider mite strains tested differed in the numbers of heat shock genes (Hsps) induced under moderate or high temperature exposure. In thermal preference (Tp) assays, the two Wolbachia-infected spider mite strains preferred a lower temperature than strains without Wolbachia. Our results show that endosymbiont-mediated spider mite responses to temperature stress are complex, involving a combination of changing endosymbiont infection patterns, altered thermoregulatory behavior, and transcription responses.

Double infection of Wolbachia and Spiroplasma alters induced plant defense and spider mite fecundity.

Herbivore-associated bacterial symbionts can change plant physiology and influence herbivore fitness. The spider mite Tetranychus truncatus is a notorious pest harboring various bacterial symbionts; however, the effect of bacterial symbionts on host plant physiology remains unclear. Here, we investigated whether infection with the endosymbionts Wolbachia and Spiroplasma altered spider mite performance on tomato plants and affected plant-induced defenses. Wolbachia and Spiroplasma were mainly located in the gnathosoma and ovaries of their spider mite hosts. Wolbachia and Spiroplasma significantly improved spider mite reproductive performance in cultivated and wild-type tomato. However, in plants deficient in jasmonic acid (JA) and salicylic acid (SA), there were no significant differences in reproduction between spider mites infected with Wolbachia and Spiroplasma and uninfected mites. The results indicated that the reproduction benefits conferred by endosymbionts may relate to plant defenses. Both spider mites infected with Wolbachia and Spiroplasma and uninfected mites induced similar levels of JA and SA accumulation in tomato, whereas tomato plants damaged by spider mites infected with both Wolbachia and Spiroplasma showed lower expression levels of JA- and SA-responsive genes than those damaged by uninfected spider mites. In addition, mites infected with Wolbachia and Spiroplasma mites consumed more tomato amino acids compared to uninfected spider mites, which may have contributed to host fecundity. Our results suggest that the reproduction benefits conferred by endosymbionts may be associated with changes in plant defense parameters and the concentrations of plant amino acids. The results highlight the importance of endosymbionts in interactions between spider mites and their host plants. © 2020 Society of Chemical Industry.

Variation in the microbiome of the spider mite Tetranychus truncatus with sex, instar and endosymbiont infection.

Most arthropod-associated bacterial communities play a crucial role in host functional traits, whose structure could be dominated by endosymbionts. The spider mite Tetranychus truncatus is a notorious agricultural pest harboring various endosymbionts, yet the effects of endosymbionts on spider mite microbiota remain largely unknown. Here, using deep sequencing of the 16S rRNA gene, we characterized the microbiota of male and female T. truncatus with different endosymbionts (Wolbachia and Spiroplasma) across different developmental stages. Although the spider mite microbiota composition varied across the different developmental stages, Proteobacteria were the most dominant bacteria harbored in all samples. Positive relationships among related operational taxonomic units dominated the significant coassociation networks among bacteria. Moreover, the spider mites coinfected with Wolbachia and Spiroplasma had a significantly higher daily fecundity and juvenile survival rate than the singly infected or uninfected spider mites. The possible function of spider-mite associated bacteria was discussed. Our results highlight the dynamics of spider mite microbiotas across different life stages, and the potential role of endosymbionts in shaping the microbiota of spider mites and improving host fitness.

Comparative analyses of salivary proteins from the facultative symbiont-infected and uninfected Tetranychus truncatus

Salivary proteins of herbivorous insects play a central role in plant-insect interactions. Spider mite Tetranychus truncatus is a polyphagous agricultural pest harboring various bacterial symbionts. However, whether endosymbionts infection in spider mite alters the host saliva protein remains largely unknown. Here, by using shotgun LC-MS/MS analysis, we identified and characterized the components of saliva in Wolbachia-Spiroplasma infected and uninfected T. truncatus. In total, 177 putative salivary proteins were identified. The function of many proteins remains unknown, while in numerous cases belong to catalytic activity and binding proteins. The saliva enzymes included oxidoreductase, hydratase, isomerase, transferase, protease, esterase, ribonuclease, kinase, lyase and phosphorylase. Other proteins, such as ATP-binding, actin, heat shock proteins and vitellogenin were also detected in the T. truncatus saliva. In addition, we found some of the saliva proteins are mite strain-specific salivary proteins—14 proteins were only found in Wolbachia-Spiroplasma infected spider mite, and 6 proteins were only found in Wolbachia-Spiroplasma uninfected spider mite. Overall, this is the first research to identify and characterize the proteins in saliva of facultative symbionts-infected and uninfected spider mites, T. truncatus. Our novel findings revealed that the presence of bacterial symbionts affected the saliva components of spider mites, opening the path for future studies.

Unresolved Problems Related to Scrub Typhus: A Seriously Neglected Life-Threatening Disease

Unresolved Problems Related to Scrub Typhus: A Seriously Neglected Life-Threatening Disease

Host-Symbiont Interactions in Spider MiteTetranychus truncatesDoubly Infected WithWolbachiaandCardinium

Inherited bacteria Wolbachia, and more recently Cardinium, have received a great deal of attention for their ability to manipulate the reproduction and fitness of their host species. Wolbachia and Cardinium have been found to co-infect the same host species. In this study, both Wolbachia and Cardinium were found to manipulate host reproduction through cytoplasmic incompatibility and to affect the male-biased sex-ratio in the doubly infected spider mite Tetranychus truncates Ehara. We also investigated effects of double infection with Wolbachia and Cardinium on host fecundity and longevity. Results indicated that Wolbachia and Cardinium increased the fecundity of doubly infected females, although no infection effect on host longevity was observed. Our most important finding was that the mating of uninfected mites facilitated the proliferation of Wolbachia and Cardinium in double-infected mites. We discuss the results observed with respect to the spread of bacterial infection in natural populations and the evolution of the endosymbiont-T. truncates symbiosis.

Fitness Cost ofLitomosoides sigmodontisFilarial Infection in Mite Vectors; Implications of Infected Haematophagous Arthropod Excretory Products in Host-Vector Interactions

Filariae are a leading cause of infections which are responsible for serious dermatological, ocular, and vascular lesions. Infective third stage larvae (L3) are transmitted through the bite of a haematophagous vector. Litomosoides sigmodontis is a well-established model of filariasis in the mouse, with the vector being the mite Ornithonyssus bacoti. The aim of the study was to analyse the filarial infection in mites to determine the consequences of filarial infection in the blood-feeding and the reproduction of mites as well as in the regulation of vector-induced inflammation in the mouse skin. Firstly, L3 are unevenly distributed throughout the host population and the majority of the population harbours a moderate infection (1 to 6 L3). Filarial infection does not significantly affect the probing delay for blood feeding. The number of released protonymphs is lower in infected mites but is not correlated with the L3 burden. Finally, induced excreted proteins from infected mites but not from uninfected mites stimulate TNF-α and the neutrophil-chemoattractant KC production by antigen-presenting cells (APCs). Altogether, these results describe the modification of the mite behavior under filarial infection and suggest that the immunomodulatory capacity of the mite may be modified by the presence of the parasite, hindering its defensive ability towards the vertebrate host.

Influence of <I>Orientia tsutsugamushi</I> Infection on the Developmental Biology of <I>Leptotrombidium imphalum</I> and <I>Leptotrombidium chiangraiensis</I> (Acari: Trombiculidae)

Leptotrombidium chiangraiensis Tanskul & Linthicum, and Leptotrombidium imphalum Vercammen-Grandjean are important vectors of scrub typhus in rice field habitats in northern Thailand. The developmental biology of all stages of the life cycle of two generations of these species of mites infected with Orientia tsutsugamushi (Hayashi) and uninfected mites is reported. The development of the infected lines of both F1 and F2 L. chiangraiensis were significantly longer than their respective uninfected lines (P < 0.05). The developmental times of uninfected and infected F1 lines of L. imphalum were not significantly different; however, F2 infected lines took significantly longer to develop (P < 0.05). Both F1 and F2 generations of infected L. imphalum and L. chiangraiensis oviposited on average >150 fewer eggs than uninfected mites.

Variable fitness and reproductive effects of Wolbachia infection in populations of the two-spotted spider mite Tetranychus urticae Koch in China

Maternally inherited Wolbachia bacteria are widely distributed among insects, and their presence usually causes modifications of the host. To understand the evolutionary history of diverse host-Wolbachia associations, we investigated the symbiosis between Wolbachia and the two-spotted spider mite Tetranychus urticae Koch in China. The cytoplasmic incompatibility (CI) level, fecundity, female ratio, host longevity and host development time were examined. Our results indicate that Wolbachia bacteria had variable effects on the reproduction and fitness of Chinese populations of T. urticae. Variability of CI expression within T. urticae ranged from no CI to a strong level of CI in spite of the low variability of the wsp gene. Relative to uninfected mites, infected females in one of the three populations showed enhanced fecundity associated with the infection of Wolbachia. This is the first report of a Wolbachia infection promoting the fecundity of infected females in T. urticae. Furthermore, we found both positive and negative effects of Wolbachia infection on longevity and the development time. The differences in ecological characters may be attributed to both Wolbachia and host genotype.

Molecular detection and differentiation of Brazilian and African isolates of the entomopathogen Neozygites tanajoae (Entomophthorales: Neozygitaceae) with PCR using specific primers

Neozygites tanajoae is an entomopathogenic fungus which has been used for biocontrol of the cassava green mite (Mononychellus tanajoa, CGM) in Africa. Establishment and dispersal of Brazilian isolates which have been introduced into some African countries in recent years to improve CGM control was followed with specific PCR assays. Two primer pairs, NEOSSU_F/NEOSSU_R and 8DDC_F/8DDC_R, were used to differentiate isolates collected from several locations in Brazil and from three countries in Africa, Benin, Ghana and Tanzania. The first primer pair enabled the species-specific detection of Neozygites tanajoae, while the second differentiated the Brazilian isolates from those of other geographical origin. PCR assays were designed for detection of fungal DNA in the matrix of dead infested mites since N. tanajoae is difficult to isolate and culture on selective artificial media. Our results show that all isolates (Brazilian and African) that sporulated on mummified mites were amplified with the first primer pair confirming their Neozygites tanajoae identity. The second pair amplified DNA from all the Brazilian isolates, but did not amplify any DNA samples from the African isolates. None of the two primers showed amplification neither from any of the non-sporulating mite extracts nor from the dead uninfected mites used as negative controls. We confirmed that the two primer pairs tested are suitable for the detection and differential identification of N. tanajoae isolates from Brazil and Africa and that they are useful to monitor the establishment and spread of the Brazilian isolates of N. tanajoae introduced into Benin or into other African countries for improvement of CGM biocontrol.

Cardinium symbionts cause cytoplasmic incompatibility in spider mites

Intracellular symbiotic bacteria belonging to the Cytophaga-Flavobacterium-Bacteroides lineage have recently been described and are widely distributed in arthropod species. The newly discovered bacteria, named Cardinium sp, cause the expression of various reproductive alterations in their arthropod hosts, including cytoplasmic incompatibility (CI), induction of parthenogenesis and feminization of genetic males. We detected 16S ribosomal DNA sequences similar to those of Cardinium from seven populations of five spider mite species, suggesting a broad distribution of infection of Cardinium in spider mites. To clarify the effect of Cardinium on the reproductive traits of the infected spider mites, infected mites were crossed with uninfected mites for each population. In one of the populations, Eotetranychus suginamensis, CI was induced when infected males were crossed with uninfected females. The other six populations of four species showed no reproductive abnormalities in the F(1) generation, but the possibility of CI effects in the F(2) generation remains to be tested. One species of spider mite, Tetranychus pueraricola, harbored both Cardinium and Wolbachia, but these symbionts seemed to have no effect on the reproduction of the host, even when the host was infected independently with each symbiont.

Horizontal transmission of fungal infection by Metarhizium anisopliae in parasitic Psoroptes mites (Acari: Psoroptidae)

Abstract Ectoparasitic mites of the genus Psoroptes cause mange in a wide range of domestic and wild vertebrate hosts. The mite infestation may be localised in the ear of the host, or be more generalised over the body. In the latter case, infestation may be debilitating and often fatal, particularly in domesticated cattle, sheep and goats. At present, control depends on the use of organophosphate or pyrethroid plunge dips or injectable endectocides. A series of in vivo bioassays are described here to further evaluate the use of an entomopathogenic fungus, Metarhizium anisopliae (Metschnikoff) as a biological control agent for Psoroptes mites. Mites were obtained from the ears of rabbits ( Psoroptes ovis (Hering) syn. Psoroptes cuniculi ). High levels of mortality (>94%) were observed in all life-cycle stages when exposed to a 1 × 10 8 conidia ml −1 suspension; there were no significant differences in infection between the different life-cycle stages. The treatment of eggs, however, had no effect on hatch rate. The horizontal transmission of the pathogen was considered by placing live uninfected mites in experimental chambers with an infected cadaver, but preventing direct contact using a mesh cage which would allow the passage of conidia but exclude direct physical contact. None of the uninfected mites showed signs of mycosis-induced mortality, indicating that direct contact with the cadaver was required for infection. Uninfected live mites were then brought into direct contact with an infected cadaver by a single touch of the mite to the cadaver ( M. anisopliae between infected Psoroptes mites, when used as a biological control agent, on an infected host is discussed.

Infection of Psoroptes mites with the fungus Metarhizium anisopliae.

The astigmatid mite, Psoroptes ovis (Hering) (Acari: Psoroptidae), is an obligatory ectoparasite that causes psoroptic mange in a range of domesticated animals, particularly sheep, where the clinical disease is known as sheep scab. A series of laboratory assays were used to assess the use of the fungus, Metarhizium anisopliae (Metchnikoff) (Deuteromycotina: Hyphomycetes) as a biocontrol agent for P. ovis derived from rabbits (syn. P. cuniculi). The immersion of mites in a suspension of conidia of M. anisopliae resulted in the acquisition of fatal infections. The number of mites which developed infections increased significantly with the increasing concentration of the conidial suspension to which they were exposed; 77% of mites developed infections when exposed to the highest concentration used (1 x 10(8) conidia ml(-1)). Controls developed no fungal infections. Mites allowed simply to walk across a surface which had been treated with a suspension of conidia also acquired fungal infections; the number infected was again related to the concentration of conidia present. After contact for 24 h with a surface treated with 1 x 10(8) conidia ml(-1), 73% of the mites became infected. To determine whether dead infected mites could act as sources of infection, infected cadavers were placed in chambers with live uninfected mites. The uninfected mites acquired fatal infections from the cadavers; a higher ratio of infected cadavers to uninfected mites resulted in greater transmission of infection. The time after death of the infected cadaver was also an important factor influencing the number infected, 5-day-old cadavers were the most infective and 18-day-old cadavers the least infective. The results indicate that M. anisopliae is a good candidate control agent for Psoroptes mites.

Vertical transmission of Orientia tsutsugamushi in two lines of naturally infected Leptotrombidium deliense (Acari: Trombiculidae).

Vertical transmission of Orientia tsutsugamushi (Hayashi), the etiologic agent for scrub typhus, was studied in two lines of naturally infected Leptotrombidium deliense Walch. In one line of mites originating from a single adult (V3M), the rate of filial transmission was 100% for the first two laboratory generations, but declined to 86.6% in the third laboratory generation. The vertical infection rate in this line of mites was 100% for the parental generation, but declined to 95.6% for the F1 generation and 88.6% for F2. The transmission of O. tsutsugamushi in another line of L. deliense (V3F) was less efficient than mites originating from V3M. In the initial laboratory generation of V3F a filial transmission rate of 100% was recorded. However, none of the F2 generation of this line transmitted rickettsiae to mice (Mus musculus L.), resulting in a filial transmission rate of 0%. Transmission of O. tsutsugamushi to mice by progeny from cohort larvae originally from the same adult (V3F) was also studied in the laboratory and these were found to be relatively poor transmitters of rickettsiae. The filial infection rate of F2 larvae was 60%, F3 was 88.8%, and F4 was 55.9%. The biology of infected L. deliense was studied and compared with uninfected mites reared under the same laboratory conditions. The results showed that infected female L. deliense laid approximately the same or more eggs as uninfected adults. The rate of development of the progeny of infected L. deliense was not significantly different from uninfected mites.

Effects of Microsporidium phytoseiuli (Microsporidia) on the Performance of the Predatory Mite, Phytoseiulus persimilis (Acari: Phytoseiidae)

Abstract Five-day test periods were used to evaluate the effects of Microsporidium phytoseiuli on short-term oviposition, survival, and prey consumption rates of Phytoseiulus persimilis, a predator of phytophagous mites, from a European source. Sex ratios, lifetime oviposition rates, and lifetime longevity of microsporidian-infected females were compared to those of uninfected females from a second source. All tests were conducted under controlled conditions (16L:8D; 25°C:20°C; 70 ± 10% RH). Mean fecundity and prey consumption of microsporidian-infected females were significantly lower than those of uninfected females from the same source. Uninfected and microsporidian-infected females produced 2.6 ± 0.2 and 1.7 ± 0.2 eggs/female/day, respectively, over a 5-day period. Fecundity values were similar for predators during prey consumption studies. Mean prey consumption over 5 days was 18.7 ± 1.0 and 13.4 ± 1.2 deuteronymph Tetranychus urticae /female/day for uninfected and infected mites, respectively. Short-term survivability was variable and proved to be an unreliable means to evaluate predator quality. Microsporidian-infected females produced significantly fewer eggs and female progeny during their lifetimes and uninfected females lived significantly longer than infected females. Results of short-term performance tests were compared to minimum performance standards outlined in current quality control guidelines. Mean fecundity for uninfected female predators exceeded recommended standards whereas the fecundity of microsporidian-infected females remained below minimal performance standards. In this study, performance was evaluated for predators in which all individuals in a sample were either infected or uninfected with the microsporidium. Random sampling of populations with moderate infection rates is more likely to occur in commercial settings and performance may remain relatively high in samples in which not all individuals are infected. Therefore, performance values alone may provide insufficient information to fully assess predator quality. Without routine examination of individuals for microsporidia, it is likely that these pathogens will remain undetected, only to be discovered when poor performance or mortality is noted due to high disease prevalence.

Wolbachia and cytoplasmic incompatibility in the spider mites Tetranychus urticae and T. turkestani

Wolbachia form a group of closely related intracellular Proteobacteria that manipulate reproduction of their arthropod host in various ways. They are widespread in insects, but have not been not looked for in other arthropods except a few isopods and a predatory mite. Recently, Wolbachia were demonstrated to be widespread in mites also. Here, I report that Wolbachia induce cytoplasmic incompatibility in two spider mite species, Tetranychus urticae and T. turkestani, in crosses between infected and uninfected individuals. Uninfected mites were derived from the infected lineage by antibiotic treatment. Similar to other examples of cytoplasmic incompatibility, subsequent crosses between uninfected (cured) female and infected male spider mites were different from all other cross combinations. This suggests that the dynamics and evolution in Wolbachia–mite relationships may share many features with the Wolbachia–insect systems. Interestingly, the incompatible cross showed high F1 zygotic mortality among females, but not among males. This zygotic mortality in the haplodiploid spider mites was in sharp contrast to the phenotypic effects of cytoplasmic incompatibility reported previously in haplodiploid insects. In the latter, cytoplasmic incompatibility results in all male or male-biased offspring because of haploidization of the fertilized egg with little or no zygotic mortality. Possible explanations are low bacterial densities and the different, holokinetic chromosome structure in spider mites.

Wolbachia and cytoplasmic incompatibility in the spider mites Tetranychus urticae and T. turkestani

Wolbachia form a group of closely related intracellular Proteobacteria that manipulate reproduction of their arthropod host in various ways. They are widespread in insects, but have not been not looked for in other arthropods except a few isopods and a predatory mite. Recently, Wolbachia were demonstrated to be widespread in mites also. Here, I report that Wolbachia induce cytoplasmic incompatibility in two spider mite species, Tetranychus urticae and T. turkestani, in crosses between infected and uninfected individuals. Uninfected mites were derived from the infected lineage by antibiotic treatment. Similar to other examples of cytoplasmic incompatibility, subsequent crosses between uninfected (cured) female and infected male spider mites were different from all other cross combinations. This suggests that the dynamics and evolution in Wolbachia–mite relationships may share many features with the Wolbachia–insect systems. Interestingly, the incompatible cross showed high F1 zygotic mortality among females, but not among males. This zygotic mortality in the haplodiploid spider mites was in sharp contrast to the phenotypic effects of cytoplasmic incompatibility reported previously in haplodiploid insects. In the latter, cytoplasmic incompatibility results in all male or male-biased offspring because of haploidization of the fertilized egg with little or no zygotic mortality. Possible explanations are low bacterial densities and the different, holokinetic chromosome structure in spider mites.