Until recently, mites in the families Ascidae, Blattisociidae and Melicharidae together constituted what was considered to be a single family, the Ascidae (sensu lato). We include all three families in this catalogue because of their many morphological similarities, as well as for historic and ecological reasons. Together with most Phytoseiidae and some Ameroseiidae, these are the only mesostigmatid mites commonly found on plants. In this publication we initially provide a historic overview of these groups, summarising the changes in the taxonomic concepts of the genera and other subfamilial taxa. This is followed by a thorough characterisation of each family and genus. A dichotomous key for the separation of families and genera is included. We then list the species considered to belong to these families, with details of the literature concerning the taxonomy of each species, and information about their type specimens and type localities wherever possible. The numbers of taxa considered as valid in this publication are: 372 species in 17 genera of Ascidae, 367 species in 14 genera of Blattisociidae, and 206 species in 11 genera of Melicharidae. We attempt to place each species in the most appropriate genus. In doing so, we propose 30 new combinations, including a species here transferred from Ascidae sensu stricto to Rhodacaridae. We propose five new names to replace junior homonyms, one new generic synonymy, and one new specific synonymy. Some species are insufficiently known and could not be reliably placed in any genus; these are listed as species incertae sedis. We also provide a list of species and genera that have been placed in these families at some time, but which have been transferred to other groups.

The blattisociid mite Lasioseius floridensis Berlese was found associated with the broad mite, Polyphagotarsonemus latus (Banks), on gerbera leaves in Mogi das Cruzes, State of Sao Paulo, Brazil. Blattisociid mites are not common on aerial plant parts, except under high air humidity levels. Some Lasioseius species have been mentioned as effective control agents of rice pest mites, but nothing is known about the biology of L. floridensis. The objective of this study was to evaluate whether the observed co-occurrence of L. floridensis and P. latus was just occasional or whether the latter could be important as food source for the former, assumed by laboratory evaluation of the ability of the predator to maintain itself, reproduce and develop on that prey. Biological parameters of L. floridensis were compared when exposed to P. latus and to other items as food. The study showed that mating is a pre-requisite for L. floridensis to oviposit and that oviposition rate was much higher on the soil nematode Rhabditella axei (Cobbold) (Rhabditidae) than on P. latus. Ovipositon on the acarid mite Tyrophagus putrescentiae (Schrank) was about the same as on P. latus, but it was nearly zero when the predator was fed the fungi Aspergillus flavus Link or Penicillium sp., or cattail (Typha sp.) pollen. Survivorship was higher in the presence of pollen and lower in the presence of A. flavus or Penicillium sp. than in the absence of those types of food. Life table parameters indicated that the predator performed much better on R. axei than on P. latus. To evaluate the potential effect of L. floridensis as predator of P. latus, complementary studies are warranted to determine the frequency of migration of L. floridensis to aerial plant parts, when predation on P. latus could occur.

Predatory behaviour and reproductive output of the ladybird beetle Stethorus tridens Gordon as function of the tomato red spider mite (TRSM), Tetranychus evansi Baker & Pritchard, densities was investigated in the laboratory. Adult female of S. tridens were isolated in cylindrical plastic arenas, containing a leaf disc of Solanum americanum Mill. with 5, 20, 40, 60, 80 or 100 T. evansi nymphs. The number of prey consumed and eggs laid were evaluated daily for ten consecutive days, starting at the oviposition. Oviposition of S. tridens was positively correlated with prey consumption and lower threshold prey consumption for S. tridens laying eggs was 16.3 mites per day. The instantaneous rate of attack (ca. discovery area) and the handling time were 0.0062 h -1 and 0.83 h, and 0.00254 h -1 and 0.78 h, respectively, for predators at the 1st-and 10th-oviposition day. The predator exhibited a type II functional response at 1st-and 10th-oviposition day with a maximum consumption per predator of 33 T. evansi nymphs per day at the highest prey density. The ladybird beetle S. tridens is often collected associated with red spider mite colonies on solanaceous wild plants and the results suggest the potential of this ladybird beetle to control T. evansi in tomatoes crops.

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.