Catalogue of the free-living and arthropod-associated Laelapidae Canestrini (Acari: Mesostigmata), with revised generic concepts and a key to genera.

The cosmopolitan mite family Laelapidae includes both free-living predatory species and species associated with arthropods, mammals or birds. This work presents a list of free-living and arthropod-associated species of laelapids, with corresponding taxonomic information and references. It includes 1088 species (in addition to three subspecies) assigned to 73 genera, 61 new combinations and two new synonymies at the generic level. Laelaps (Apolaelaps) Silvestri is raised to the generic level. Many of the species described before about 1950 are poorly characterised and cannot be classified with confidence at the family or generic level. Hence, ten genera, one subgenus, 121 species (ca. 70% of which were reported as Hypoaspis Canestrini or Laelaps (Hypoaspis) Canestrini) and one subspecies, are considered incertae sedis, because of their inadequate morphological characterisation in the literature. Some of these may not even belong to the Laelapidae or to the groups of interest for this publication. A total of 89 species, 30 genera, one subgenus, one tribe and one subfamily previously associated with genera treated in this catalogue are now placed in other families or, less commonly, in laelapid genera not considered here because they are considered essentially vertebrate parasites (taxa excluded). Twenty-six other species (one cited as a "variety") are cited as nomina nuda. An illustrated key to the 73 genera included in the catalogue along with revised generic diagnoses are provided.

Semi-field evaluation of the predation of Macrocheles embersoni and Macrocheles muscaedomesticae (Acari: Mesostigmata: Macrochelidae) on the house fly and the stable fly (Diptera: Muscidae).

BACKGROUND: The house fly, Musca domestica L., and the stable fly, Stomoxys calcitrans (L.), are important and harmful organisms. The cosmopolitan house fly is not parasitic, but the adults are annoying and a known vector of several pathogens. The importance of the stable fly has increased in Brazil in the last 40 years, after major changes in sugarcane cultivation practices were implemented, including the widespread application of vinasse (byproduct in sugarcane mills) and the parallel reduction of sugarcane preharvest burning. These changes have favored the development of this fly, which can reach high populations, that can negatively affect cattle and other animals. The control of these flies relies heavily on the use of chemical products, which very often do not provide adequate population reduction. Predatory mites of the family Macrochelidae have been evaluated under laboratory conditions for the biological control of these organisms, especially of the house fly. The objective of this study was to examine the predation capacity of the macrochelids Macrocheles embersoni Azevedo, Castilho & Berto and Macrocheles muscaedomesticae (Scopoli) on the house fly and the stable fly, under semi-field conditions (screen-houses). RESULTS: Reductions of 83 to 90% of the house fly and 66 to 73% of the stable fly populations were observed, with the release of 100 of these predators per square meter. CONCLUSIONS: The number of adults of both fly species was much lower in the units where the predators had been released than in the others. However it is suggested that provisioning and or conserving alternative food sources for these macrochelids, such as free-living nematodes, could further improve biocontrol efficacy.

Performance of Tetranychus urticae (Acari: Tetranychidae) on three hop cultivars (Humulus lupulus).

Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest species in numerous crops including hop (Humulus lupulus L.). Substantial T. urticae infestation was observed to occur in this recently introduced crop in Brazil. The adoption of less suitable cultivars to the pest species is highly desirable for integrated pest management. We used free-choice trials and two-sex life table analysis to determine the preference and population growth of T. urticae under laboratory conditions using three of hop cultivars currently expanding in Brazil (Mantiqueira, Victoria, and Yakima Gold). We also estimated the density of non-glandular trichomes and lupulin glands found on the abaxial leaf surface of these cultivars and correlated them with performance parameters of T. urticae. Mantiqueira appeared to be the least preferred by adult females for attractiveness and oviposition suggesting existence of antixenosis on this cultivar. Female immature stages developed slower on Yakima Gold and Mantiqueira, but no difference was observed between the latter and Victoria. Fecundity and longevity were significantly lower on Mantiqueira than on Victoria and Yakima Gold. No significant differences were observed among cultivars for intrinsic rate of increase (r), finite rate of increase (λ), and net rate of reproduction (R0), suggesting the absence of antibiosis. Although, lupilin gland densities were higher on Mantiqueira and Yakima Gold than on Victoria, no significant correlations were observed between these defensive traits and performance parameters of T. urticae. However, 30-day population simulations of T. urticae suggest that Yakima Gold is the least susceptible, Mantiqueira is moderately susceptible, and Victoria is highly susceptible.

Mites of the genus Gaeolaelaps (Acari: Laelapidae) from southern Brazil, with description of two new species.

Gaeolaelaps Evans Till is a laelapid genus composed of free living mites, some of which have been produced commercially for use as biological control agents of pest organisms. They are edaphic and poorly known in Brazil, from where a single species has so far been reported (Gaeolaelaps aculeifer (Canestrini)). The objective of this paper is to report the occurrence of three other species from this country, two of which are new to science (G. azul n. sp., G. cerrii n. sp. and G. circularis Hyatt).

Reinstatement of Metatarsonemus Attiah (Acari: Tarsonemidae), with description of a new species, redefinition of the genus and a key to the world species.

A new species, Metatarsonemus caissara Lofego Cavalcante sp. nov., is described based on females and males collected on Eugenia umbelliflora O. Berg. (Myrtaceae) from Atlantic Forest areas of São Paulo State, Brazil. Metatarsonemus Attiah is reinstated as a genus based on apomorphic attributes which are recovered through examination of specimens of the new species herein described, in addition to specimens of M. simplicissimus Attiah and M. megasolenidii Lofego Ochoa. A cladistic analysis tentatively indicates that the Metatarsonemus lineage is sister group to a lineage comprising the genera complex Daidalotarsonemus+Ceratotarsonemus+Excelsotarsonemus in sharing four homoplasious apomorphic attributes. A dichotomous key is provided for identification of the species of this genus described so far.

Mulching with coffee husk and pulp in strawberry affects edaphic predatory mite and spider mite densities.

Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants-Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.

Rearing system for the predatory phytoseiid Euseius concordis (Acari: Phytoseiidae).

Several species of predatory mites, especially those of the family Phytoseiidae, are potentially useful for the control of pest mites and insects. Among the phytoseiids, Euseius concordis (Chant), a species commonly found in South America, has been studied for possible use as biological control agent of pest mites. Given that Euseius species are known to feed on plant leaves and on pollen, the objective of this study was to determine plant species and pollen sources suitable to establish a pilot method of production of that species, based on a set of comparisons in the laboratory. Out of four plant species evaluated in the study, higher survivorship of E. concordis females in the absence of supplementary food was observed on leaflets of Canavalia ensiformis L. Out of two pollen types, higher survivorship was obtained on pollen of Typha domingensis L. In a subsequent step, the population of E. concordis increased 19.3× within 21 days when that pollen of T. domingensis was offered to the predator on plantlets of C. ensiformis, at 25.0 ± 1 °C, 70.0 ± 10% RH and 12 h photophase. Future studies may confirm the economic viability of this setup for the mass production of E. concordis.

Influence of fruit age of the Brazilian Green Dwarf coconut on the relationship between Aceria guerreronis population density and percentage of fruit damage.

The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is one of the main coconut pests in the American, African and parts of the Asian continents, reaching densities of several thousand mites per fruit. Diagrammatic scales have been developed to standardize the estimation of the population densities of A. guerreronis according to the estimated percentage of damage, but these have not taken into account the possible effect of fruit age, although previous studies have already reported the variation in mite numbers with fruit age. The objective of this study was to re-construct the relation between damage and mite density at different fruit ages collected in an urban coconut plantation containing the green dwarf variety ranging from the beginning to nearly the end of the infestation, as regularly seen under field conditions in northeast Brazil, in order to improve future estimates with diagrammatic scales. The percentage of damage was estimated with two diagrammatic scales on a total of 470 fruits from 1 to 5 months old, from a field at Ilhéus, Bahia, Brazil, determining the respective number of mites on each fruit. The results suggested that in estimates with diagrammatic scales: (1) fruit age has a major effect on the estimation of A. guerreronis densities, (2) fruits of different ages should be analyzed separately, and (3) regular evaluation of infestation levels should be done preferably on fruits of about 3-4 months old, which show the highest densities.

Factitious food for mass production of predaceous phytoseiid mites (Acari: Phytoseiidae) commonly found in Brazil.

Phytoseiid mites are commonly used as biological control agents of mite and small insect pests. To facilitate the production of phytoseiids, alternative food sources have been evaluated. The aim of this study was to evaluate the suitability of different food sources for the rearing of the phytoseiids Amblyseius tamatavensis Blommers, Euseius concordis (Chant) and Neoseiulus anonymus (Chant and Baker). This study evaluated the levels of oviposition of these predators when fed with 15 Astigmatina (Sarcoptiformes) mite species, one species of a bacteriophagous nematode, and pollen from five plant species. The highest oviposition rates of A. tamatavensis were obtained when fed on the mites Thyreophagus cracentiseta Barbosa, OConnor & Moraes and Aleuroglyphus ovatus (Troupeau) (2.6 and 2.1 eggs/female/day, respectively). The five highest oviposition levels of E. concordis occurred when the food source was pollen, especially of Ricinus communis L. (1.7 eggs/female/day). The evaluated oviposition levels of N. anonymus were at most 0.5 eggs/female/day on all food sources. The construction of life tables of A. tamatavensis and E. concordis with the two most favorable food sources showed that in both cases the values of rm were higher when the predator was fed with T. cracentiseta and R. communis, respectively. The possible use of pollen of Elaeis guineensis L. should be further evaluated, given the acceptance of this type of pollen by E. concordis and the ease of obtaining large amounts of this pollen in areas where this crop is grown.

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.

Potential of Five Brazilian Populations of Phytoseiidae (Acari) for the Biological Control of Bemisia tabaci (Insecta: Hemiptera).

Biotype B of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), causes considerable losses to growers worldwide. Phytoseiid mites have been successfully used for the control of this pest in several countries. The Brazilian phytoseiid fauna is very diverse and potentially useful for this purpose. The aim of this study was to evaluate five Brazilian populations of phytoseiids as candidates for the control of the whitefly, a serious pest of different crops worldwide. Evaluated species were Amblydromalus limonicus (Garman & McGregor), Amblyseius herbicolus (Chant), Amblyseius largoensis (Muma), Amblyseius tamatavensis (Blommers), and Neoseiulus tunus (De Leon), which are found naturally in Brazil and elsewhere. The work was conducted at 28±1°C, 75±10% relative humidity, and a photoperiod of 12:12 (L:D) h. All evaluated phytoseiids preyed on eggs of B. tabaci, with the highest levels of predation recorded for Am. herbicolus and N. tunus, and highest level of oviposition recorded for Am. tamatavensis. The results show the Brazilian populations of those three species to be promising as control agents of B. tabaci. Aleuroglyphus ovatus (Troupeau) (Acari: Acaridae) was found to be a suitable prey for the mass production of those predators. Complementary studies are considered justified, given the positive results of this study.

Potential of two populations of Amblyseius swirskii (Acari: Phytoseiidae) for the control of Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) in Brazil.

Predatory mites of the family Phytoseiidae are commercialized in European and North American countries for the control of whiteflies (Insecta: Aleyrodidae). Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is one of the predators used for that purpose. This predator is not found in Brazil and in many other countries, but its introduction could promote biological control of Bemisia tabaci (Gennadius) biotype B (silverleaf whitefly) in those countries. The aim of this study was to compare two populations of A. swirskii as predators of eggs of B. tabaci of two different ages, as well as the acceptance of those populations for other food types [eggs of Tetranychus urticae Koch; larvae and protonymphs of Aleuroglyphus ovatus (Troupeau) (Astigmatina: Acaridae) and cattail pollen (Typha domingensis Persoon)]. One of the populations of A. swirskii was collected in the Republic of Benin, in tropical Africa, and the other was commercially available in The Netherlands. The comparison was done to evaluate the population with better potential for practical use, and to determine food types that could be used for mass rearing the predator. Experiments were conducted at 28 ± 1 °C, 80 ± 10 % relative humidity and 12 h photophase. Both populations were able to oviposit when fed eggs of B. tabaci, but the Netherlands population showed higher oviposition rate (2.3 and 1.6 times higher on young and older eggs, respectively). Higher predation rates were observed for eggs up to 24 h of age in comparison with older eggs. Aleuroglyphus ovatus proved to be a promising prey for possible mass rearing of this predator in Brazil, where that astigmatic mite is found naturally when pollen was used as food, no significant difference was observed for oviposition rate between populations. The results suggested a higher potential of the Netherlands population of A. swirskii for the control of B. tabaci biotype B in this country for augmentative biological control, with the possible use of A. ovatus as food for the mass production and pollen of T. domingensis as a food supplement for this predator in practical field releases.

Diversity and population dynamics of Ascidae, Blattisociidae and Melicharidae (Acari: Mesostigmata) in tropical flowers in Brazil.

Cultivation of tropical flowers has expanded considerably in Brazil, justifying efforts to determine the arthropods associated with it. Heliconia species are some of the most important tropical flowers in Brazil. Mites of the families Ascidae, Blattisociidae and Melicharidae are commonly found on those plants. They disperse from flower to flower on hummingbirds. The objective of this study was to identify the diversity of mites of this group in tropical flowers, with emphasis on Heliconia species, in Brazil and to determine the fluctuation of the population of these mites in Piracicaba, Sao Paulo state. Specimens from Amazonas, Bahia, Pernambuco, Minas Gerais, Rio de Janeiro, Santa Catarina and São Paulo States were examined. Mites of the genera Asca and Iphidozercon (Ascidae), Cheiroseius and Lasioseius (Blattisociidae), and Proctolaelaps and Tropicoseius (Melicharidae) were collected in flowers of four plant families, with Lasioseius being the most diverse genus. Overall, most specimens found belonged to Tropicoseius, especially Tropicoseius venezuelensis Baker & Yunker; this was the dominant species on five of 13 Heliconia species/hybrids considered in this study. Samples of panicles of Heliconia rostrata Ruiz & Pavón were collected every 2 weeks, in Piracicaba. Six species of those mite families were found, among which Tropicoseius heliconiae Baker & Yunker and T. venezuelensis were the most numerous. The highest population levels of mites of those three families occurred at the beginning and at the end of the year, coinciding with the highest levels of rainfall, relative humidity and temperature, when plant flowers were most numerous and vigorous. Along each panicle, the highest mite densities were found in inflorescences of the three distal eighths of the panicles, where nectar and pollen were probably most abundant.

A method to estimate the population level of Aceria litchii (Prostigmata: Eriophyidae) and a study of the population dynamics of this species and its predators on litchi trees in southern Brazil.

Litchi (Litchi chinensis Sonnerat) is native to Southeast Asia, where most of the world cultivation of this crop is done. Its commercial cultivation in Brazil is recent and concentrated in the state of São Paulo. This crop has been severely damaged in Asia and Brazil by the litchi erineum mite, Aceria litchii (Keifer) (Eriophyidae). The objectives of this study were the adaptation of a method to estimate the density of A. litchii, an evaluation of the population dynamics of this pest and of its associated predators in the state of São Paulo, and an estimation of its injury levels to litchi trees. To estimate the density of A. litchii, an adaptation of a method commonly used to evaluate nematode densities in plant roots was performed. This method was shown to be adequate for the estimation of the number of A. litchii, and it might also be useful for similar evaluations of other erineum forming mites. Field samples to determine the pest population dynamics were collected monthly from August 2011 to July 2012. Sampled leaves were examined under a stereomicroscope for removal of predators and subsequent extraction ofA. litchii by the adapted method. A. litchii reached maximum densities in November 2011 and June 2012, being found at low densities between January and March 2012. The pattern of variation of A. litchii injury levels was similar to that of the density of A. litchii. The main predatory mite co-occurring with A. litchii was the phytoseiid Phytoseius intermedius Evans and McFarlane. However, high injury levels due toA. litchii suggest that the predator was unable to prevent visible damages to the trees, indicating that control activities should be adopted by growers.

A review of the status of the coconut mite, Aceria guerreronis (Acari: Eriophyidae), a major tropical mite pest.

The coconut mite (CM), Aceria guerreronis Keifer, has spread to most coconut production areas worldwide and it has been considered one of the most notorious and important pests of coconut fruits in many countries. Although CM has been reported to damage coconuts for over 40 years in the Americas and Africa it continues to cause considerable losses in countries of these continents, and in the last 15 years it has also reached countries from southeast Asia-India and Sri Lanka. Several other countries of southeast Asia are also major coconut producers and the impact by the mite in currently affected areas suggests that the dispersion of CM to these major producers could lead to very heavy losses. Great advances about our knowledge on CM and its control have been achieved, especially in the last decade, after its introduction into Asia. However, much remains to be known to allow the design of efficient strategies to it. This paper brings together information on CM invasive history, distribution, hosts, morphology, biology, dispersal, colonization process, population dynamics, symptoms and injury, estimated losses, sampling techniques, control strategies and new perspectives for its control.

Phytoseiidae (Acari: Mesostigmata) from natural ecosystems in the State of São Paulo, Brazil.

This work describes the results of a study of the phytoseiid mites collected from plants in two natural ecosystems in the State of São Paulo, Brazil-Cerrado and Atlantic Forest. In this study, 40 phytoseiid species are reported. Measurements of different structures are given for species for which measurements for the respective São Paulo populations were not previously provided. This study also includes the description of two new genera, Breviseius g. n. and Serraseius g. n., and ten new species, Amblydromalus macroatrium n. sp., Amblyseius atlanticus n. sp., Breviseius sennae n. sp., Cocoseius paucisetis n. sp., Proprioseiospsis pariquerassuensis n. sp., Serraseius caicara n. sp., Typhlodromalus ingae n. sp., Typhlodromalus feresisimilis n. sp., Typhlodromips corniformis n. sp. and Typhlodromips robustisetus n. sp.

Life history of the predatory mite Phytoseiulus fragariae on Tetranychus evansi and Tetranychus urticae (Acari: Phytoseiidae, Tetranychidae) at five temperatures.

Tetranychus evansi Baker and Pritchard and Tetranychus urticae Koch (Acari: Tetranychidae) are important pests of Solanaceae in many countries. Several studies have demonstrated that T. urticae is an acceptable prey to many predatory mites, although the suitability of this prey depends on the host plant. T. evansi, has been shown to be an unfavorable prey to most predatory mites that have been tested against it. The predator Phytoseiulus fragariae Denmark and Schicha (Acari: Phytoseiidae) has been found in association with the two species in Brazil. The objective of this work was to compare biological parameters of P. fragariae on T. evansi and on T. urticae as prey. The study was conducted under laboratory conditions at 10, 15, 20, 25 and 30 degrees C. At all temperatures, survivorship was lower on T. evansi than on T. urticae. No predator reached adulthood at 10 degrees C on the former species; even on the latter species, only about 36% of the predators reached adulthood at 10 degrees C. For both prey, in general, duration of each life stage was shorter, total fecundity was lower and intrinsic rate of population increase (r(m)) was higher with increasing temperatures. The slower rate of development of P. fragariae on T. evansi resulted in a slightly higher thermal requirement (103.9 degree-days) on that prey than on T. urticae (97.1 degree-days). The values of net reproduction rate (R (0)), intrinsic rate of increase (r(m)) and finite rate of increase (lambda) were significantly higher on T. urticae, indicating faster population increase of the predator on this prey species. The highest value of r(m) of the predator was 0.154 and 0.337 female per female per day on T. evansi and on T. urticae, respectively. The results suggested that P. fragariae cannot be considered a good predator of T. evansi.

Biological control of Bradysia matogrossensis (Diptera: Sciaridae) in mushroom cultivation with predatory mites.

Larvae of Sciaridae flies (Diptera) cause considerable damage to the mushroom Agaricus blazei (Murrill) ss. Heinemann in Brazil. Brazilian growers have had considerable difficulties in controlling this pest. The objective of this work was to test the effect of the predatory Laelapidae mite Stratiolaelaps scimitus (Womersley) as a control agent of Bradysia matogrossensis (Lane) in cultures of A. blazei. The work corresponded to an evaluation of the efficiency of that predator when released in boxes containing each about 15 L of commercial mushroom compost naturally infested with the pest. The results showed a significant effect of that predator on the population of B. matogrossensis. The release of either 665 or 1330 S. scimitus per box significantly reduced the pest population to levels that, according to grower's experience, apparently could not cause considerable damage. The positive results obtained warrant the conduction of complementary studies to determine the lowest rates of the predator that could still produce acceptable levels of control.

Effect of air humidity on the egg viability of predatory mites (Acari: Phytoseiidae, Stigmaeidae) common on rubber trees in Brazil.

Rubber pest mites, Calacarus heveae and Tenuipalpus heveae, reach economic damage levels at the end of the rainy season and the beginning of the dry season in Brazil. Therefore, low humidity adaptation might be an important characteristic for predatory mites to successfully control pest organisms. This study determined the effect of the relative humidity (RH) levels of 30-100% on the hatching of larvae of Amblyseius acalyphus, Euseius citrifolius, Iphiseiodes zuluagai, Metaseiulus camelliae, Agistemus floridanus and Zetzellia malvinae at 25 +/- 0.5 degrees C. These predatory mites are common on rubber trees in the state of São Paulo and might be used for introduction in the major rubber tree production regions in the state of Mato Grosso. At 70% RH or higher, viability was 70% or higher for all species, indicating that their performance might be higher during the rainy season than during the dry season. Eggs of E. citrifolius and M. camelliae presented higher viability at the lower relative humidity levels than those of other species, indicating that these species might have higher chance to persist in the dry season. It is suggested that M. camelliae should be further evaluated for introduction in the state of Mato Grosso, considering that this mite is not yet present in that area.

Reproductive compatibility between mite populations previously identified as Euseius concordis (Acari: Phytoseiidae).

The objective of the present research is to study the reproductive compatibility between populations of predatory mites previously identified as Euseius concordis (Chant) based on morphological characteristics. Colonies of these mite populations were established in the lab with specimens collected from different localities and host plants. Reproductive compatibility was evaluated through crosses and backcrosses within and between populations and the subsequent observation of females' oviposition, over a period of 10 days. The levels of oviposition obtained in the crosses between individuals from the same population were higher than those obtained in the crosses between individuals from different populations. Results indicate the occurrence of post-mating reproductive incompatibility between the mite population from Petrolina and the other populations studied. Crosses and backcrosses between populations involving female mites from Petrolina did not produce offspring, although endospermatophores were present inside the spermathecas of those females. Oviposition was reduced, and only sons were obtained, in crosses between populations with males from Petrolina. Crosses of females from Pontes e Lacerda and males from Jaguariúna and vice versa produced only male progeny. Our results established that the populations originating from Arroio do Meio, Pontes e Lacerda, Jaguarúna and Viçosa, are reproductively compatible. However, the latter populations and the population from Petrolina are genetically isolated. Based on these results we suggest that more cytological and genetic studies are needed to establish if this reproductive isolation represents a species barrier.