Estimating intrinsic growth rates of arthropods from partial life tables using predatory mites as examples.

The intrinsic rate of natural increase of a population (rm) has been in focus as a key parameter in entomology and acarology. It is considered especially important in studies of predators that are potential biological control agents of fast-growing pests such as mites, whiteflies and thrips. Life-table experiments under controlled laboratory conditions are standard procedures to estimate rm. However, such experiments are often time consuming and may critically depend on the precise assessment of the developmental time and the fecundity rate early in the reproductive phase. Using selected studies of predatory mites with suitable life-table data, we investigated whether and how measurements of growth rates can be simplified. We propose a new method for estimating rm from partial life tables, in which the researcher can choose a level of precision based on a stand-in measure of relative error. Based on this choice, the procedure helps the researcher to decide when a life-table experiment can be terminated. Depending on the chosen precision, significant amounts of experimental time can be saved without seriously compromising the reliability of the estimated growth parameter.

A key to the species of Protogamasellus (Acari: Ascidae), with a new species from the Brazilian Pantanal.

A study of soil mites in the Brazilian Pantanal, southwestern Brazil, has shown the frequent occurrence of the genus Protogamasellus, especially in cultivated land. Three species were found in this study, Protogamasellus mica (Athias-Henriot), Protogamasellus sigillophorus Mineiro, Lindquist Moraes, and a new species, Protogamasellus pantanal n. sp., which is here described. A taxonomic key for the identification of species of the genus was prepared, based on the examination of the type specimens of the new species here described, of specimens of other species found in Brazil in this and previous studies, and on the information found in the literature for other species.

Mites and ticks of reptiles and amphibians in Brazil.

This study focuses on the parasitic associations of mites and ticks infesting reptiles and amphibians through a multifocal approach. Herein, reptiles (n= 3,596) and amphibians (n= 919) were examined to ensure representativeness of the Brazilian herpetofauna megadiversity. The overall prevalence was calculated to better understand which were the preferred hosts for each order of Acari (Trombidiformes, Mesostigmata and Ixodida), as well as to determine which orders frequently parasitize reptiles and amphibians in Brazil, and their host specificity. Infestation rates were calculated [prevalence, mean intensity (MI) and mean abundance (MA)] for each order and species, determining which mites and ticks are more likely to be found parasitizing the ectothermic tetrapod fauna. Parasitic niches and preferred locations were recorded to help identify specific places exploited by different Acari, and to determine the host-parasite adaptations, specificity, and relationships in terms of co-evolution. In total 4,515 reptiles and amphibians were examined, of which 170 specimens were infested by mites and ticks (overall prevalence of 3.8%). Trombidiformes mites were prevalent in lizards (55.3%), followed by Ixodida on snakes (24.7%). Mesostigmata mites were the less prevalent, being identified only on Squamata reptiles (4.3% on snakes, 2.4% on lizards). In amphibians, Ixodida ticks were the most prevalent (63.2%), followed by Trombidiformes (34.6%), and lastly Oribatida (2%). From the 13 species of Trombidiformes identified, Eutrombicula alfreddugesi (19.9%) was the most abundant in terms of number of host species and infested individuals. Specimens of Ixodida, yet more common, showed low preferred locations and different values of infestation rates. Co-infestations were recorded only on snakes. Lizard mites generally adhered to the ventral celomatic area (Pterygosomatidae), and some species to the pocket-like structures (Trombiculidae). Lizards, at variance from snakes, have adapted to endure high parasitic loads with minimum effects on their health. The high number of mites recorded in the digits of toads (Cycloramphus boraceiensis, Corythomantis greening, Cycloramphus dubius, Leptodactylus latrans, Melanophryniscus admirabilis) could lead to avascular necrosis. Frogs were often infested by Hannemania larvae, while Rhinella toads were likely to be infested by Amblyomma ticks. Of note, Rhinella major toad was found infested by an oribatid mite, implying first a new parasitic relationship. The effect of high parasitic loads on critically endangered species of anurans deserves further investigation. Our results add basic knowledge to host association of mites and ticks to Brazilian reptiles and amphibians, highlighting that routine ectoparasite examination is needed in cases of quarantine as well as when for managing reptiles and amphibians in captivity given the wide diversity of Acari on the Brazilian ectothermic tetrapod fauna.

Morphometric variation of Androlaelaps fahrenholzi (Mesostigmata: Laelapidae) associated with three Sigmodontinae (Rodentia: Cricetidae) from the north of Chile.

Androlaelaps fahrenholzi is a mite with a large distribution and associated with a wide range of hosts. To assess morphometric variation of A. fahrenholzi associated with different host species (Phyllotis xanthopygus and Akodon albiventer, both from Putre, Chile) and localities (Las Chinchillas National Reserve, Fray Jorge National Park, and Llanos de Challe National Park, all in Chile and all from the host Phyllotis darwini), 41 morphological characters of each specimen were measured, and principal component analysis and discriminant analysis were used. Both analyses showed two groups separated for species of rodents. Mites associated with P. xanthopygus are smaller than those of A. albiventer. The analysis by location indicates two groups: group 1 comprises all mites collected from Fray Jorge National Park and Las Chinchillas National Reserve, and group 2 comprises only mites from Llanos de Challe National Park. These results indicate that A. fahrenholzi population can vary between hosts and geographical areas. Molecular analysis would be necessary to validate these results and determine whether they are subspecies or different species.

Mites and ticks of reptiles and amphibians in Brazil

This study focuses on the parasitic associations of mites and ticks infesting reptiles and amphibians through a multifocal approach. Herein, reptiles (n= 3,596) and amphibians (n= 919) were examined to ensure representativeness of the Brazilian herpetofauna megadiversity. The overall prevalence was calculated to better understand which were the preferred hosts for each order of Acari (Trombidiformes, Mesostigmata and Ixodida), as well as to determine which orders frequently parasitize reptiles and amphibians in Brazil, and their host specificity. Infestation rates were calculated [prevalence, mean intensity (MI) and mean abundance (MA)] for each order and species, determining which mites and ticks are more likely to be found parasitizing the ectothermic tetrapod fauna. Parasitic niches and preferred locations were recorded to help identify specific places exploited by different Acari, and to determine the host-parasite adaptations, specificity, and relationships in terms of co-evolution. In total 4,515 reptiles and amphibians were examined, of which 170 specimens were infested by mites and ticks (overall prevalence of 3.8%). Trombidiformes mites were prevalent in lizards (55.3%), followed by Ixodida on snakes (24.7%). Mesostigmata mites were the less prevalent, being identified only on Squamata reptiles (4.3% on snakes, 2.4% on lizards). In amphibians, Ixodida ticks were the most prevalent (63.2%), followed by Trombidiformes (34.6%), and lastly Oribatida (2%). From the 13 species of Trombidiformes identified, Eutrombicula alfreddugesi (19.9 %) was the most abundant in terms of number of host species and infested individuals. Specimens of Ixodida, yet more common, showed low preferred locations and different values of infestation rates. Co-infestations were recorded only on snakes. Lizard mites generally adhered to the ventral celomatic area (Pterygosomatidae), and some species to the pocket-like structures (Trombiculidae). Lizards, at variance from snakes, have adapted to endure high parasitic loads with minimum effects on their health. The high number of mites recorded in the digits of toads (Cycloramphus boraceiensis, Corythomantis greening, Cycloramphus dubius, Leptodactylus latrans, Melanophryniscus admirabilis) could lead to avascular necrosis. Frogs were often infested by Hannemania larvae, while Rhinella toads were likely to be infested by Amblyomma ticks. Of note, Rhinella major toad was found infested by an oribatid mite, implying first a new parasitic relationship. The effect of high parasitic loads on critically endangered species of anurans deserves further investigation. Our results add basic knowledge to host association of mites and ticks to Brazilian reptiles and amphibians, highlighting that routine ectoparasite examination is needed in cases of quarantine as well as when for managing reptiles and amphibians in captivity given the wide diversity of Acari on the Brazilian ectothermic tetrapod fauna.

A new species of Laelaps Koch, 1836 (Mesostigmata: Laelapidae) parasitic of the sigmodontine rodent Oligoryzomys flavescens Waterhouse, 1837 (Rodentia: Cricetidae): Molecular and morphological characterization.

Laelaps schatzi sp. nov. (Mesostigmata: Laelapidae) is described on the bases of mites collected from the sigmodontine Oligoryzomys flavescens Waterhouse, 1837 (Rodentia: Cricetidae) in Pereyra, Buenos Aires, Argentina, based on morphological, morphometric and molecular data. Two DNA fragments, mtDNA cytochrome oxidase subunit I (COI) and nuclear 18.S-ITS1-5.8S-ITS2 partial gene sequence were deposited in the public Genbank datebase. The DNA extraction was conducted nondestructively using Chelex®100 modified for this study, to prevent vouchers for further microscopically examination. Laelaps schatzi sp. nov. is similar in general appearance to Laelaps paulistanensis Fonseca, 1936 and Laelaps fonsecai Gettinger, 1992, but the new species is unique in presenting a reticulated surface pattern on the genital shield from level of Zv1 up to posterior margin, and in the presence of one or two additional impair seta/e between J4 setae of dorsal shield. Also, the phylogenetic analyses separate the new species from all other species available in the GenBank of Laelaps.

Contribution to the Uropodina mites of Peru (Acari: Mesostigmata).

Soil dwelling Uropodina mites were collected from a primary lowland rainforest in Amazonian Peru. The species found belong to three different families. A new diagnosis and the type genus of Tetrasejaspidae fam. nov. are given, and the family is recorded from Peru for the first time on the basis of Tetrasejaspis sellnicki Hirschmann, 1973. Two rotundabaloghid mites were collected (Rotundabaloghia (Circobaloghia) magna Hirschmann, 1992 and Rotundabaloghia (Circobaloghia) iquitosensis Hirschmann, 1992), both already reported from Peru. A new species (Origmatrachys peruensis sp. nov.) from the family Trachyuropodidae was collected in large numbers from soil, and is described on the basis of females, males, nymphs and larvae. This is the first description of the protonymphs and larvae of Origmatrachys. The new species differs from the previously described ones in the basis of sculptural pattern of dorsal, ventral, sternal shields and the length of the setae in the central part of the dorsal shield. A new key to the known adults and deutonymphs of Origmatrachys is given.

Ectoparasitic mites and their Drosophila hosts.

Only two parasite interactions are known for Drosophila to date: Allantonematid nematodes associated with mycophagous Drosophilids and the ectoparasitic mite Macrocheles subbadius with the Sonoran Desert endemic Drosophila nigrospiracula. Unlike the nematode-Drosophila association, breadth of mite parasitism on Drosophila species is unknown. As M. subbadius is a generalist, parasitism of additional Drosophilids is expected. We determined the extent and distribution of mite parasitism in nature Drosophilids collected in Mexico and southern California. Thirteen additional species of Drosophilids were infested. Interestingly, 10 belong to the repleta species group of the subgenus Drosophila, despite the fact that the majority of flies collected were of the subgenus Sophophora. In all cases but 2, the associated mites were M. subbadius. Drosophila hexastigma was found to have not only M. subbadius, but another Mesostigmatid mite, Paragarmania bakeri, as well. One D. hydei was also found to have a mite from genus Lasioseius attached. In both choice and no-choice experiments, mites were more attracted to repleta group species than to Sophophoran. The extent of mite parasitism clearly is much broader than previously reported and suggests a host bias mediated either by mite preference and/or some mechanism of resistance in particular Drosophilid lineages.

Parasitism by the mite sternostoma tracheacolum in the respiratory system of a Belgian canary (Serinus canaria domestica) / Parasitismo pelo ácaro de sistema respiratório Sternostoma tracheacolum em um canário belga (Serinus canaria domestica)

Background: The nasal mites of the Rhinonyssidae family include the highest diversity of mandatory hematophagous endoparasites of the respiratory system of birds. In general, these mites cause no significant lesions, except Sternostoma tracheacolum that invades the trachea, lungs and air sacs and may compromise breathing in birds. This study reports the death of a Belgian canary (Serinus canaria domestica) due to the parasitism by S. tracheacolum with an aggravating and concurrent pododermatitis infection.Case: A Belgian canary from a commercial bird flock, in which a high mortality rate had lately been recorded, was submitted to necropsy. Multiple blackened foci (1.0 mm in diameter) present in the trachea and the air sacs were subsequently identified as Sternostoma tracheacolum mites. Microscopically, there were diffuse and moderate infiltrates of lymphocytes, plasma cells, macrophages and heterophils within the tracheal submucosa and areas of fibrosis and osseous metaplasia of the tracheal cartilage. In the air sacs, there were multiple yellowish-brown foci of caseous necrosis, which were surrounded by inflammatory infiltrate of macrophages and multinucleated giant cells. In the lungs, there were foci of caseous necrosis surrounded by macrophages. In the tracheal lumen, mites sections were observed. Clusters of nucleated erythrocytes and brown granular pigment were seen withi

Background: The nasal mites of the Rhinonyssidae family include the highest diversity of mandatory hematophagous endoparasites of the respiratory system of birds. In general, these mites cause no significant lesions, except Sternostoma tracheacolum that invades the trachea, lungs and air sacs and may compromise breathing in birds. This study reports the death of a Belgian canary (Serinus canaria domestica) due to the parasitism by S. tracheacolum with an aggravating and concurrent pododermatitis infection.Case: A Belgian canary from a commercial bird flock, in which a high mortality rate had lately been recorded, was submitted to necropsy. Multiple blackened foci (1.0 mm in diameter) present in the trachea and the air sacs were subsequently identified as Sternostoma tracheacolum mites. Microscopically, there were diffuse and moderate infiltrates of lymphocytes, plasma cells, macrophages and heterophils within the tracheal submucosa and areas of fibrosis and osseous metaplasia of the tracheal cartilage. In the air sacs, there were multiple yellowish-brown foci of caseous necrosis, which were surrounded by inflammatory infiltrate of macrophages and multinucleated giant cells. In the lungs, there were foci of caseous necrosis surrounded by macrophages. In the tracheal lumen, mites sections were observed. Clusters of nucleated erythrocytes and brown granular pigment were seen withi

Parasitismo pelo ácaro de sistema respiratório Sternostoma tracheacolum em um canário belga (Serinus canaria domestica) / Parasitism by the mite sternostoma tracheacolum in the respiratory system of a belgian canary (Serinus canaria domestica)

Background: The nasal mites of the Rhinonyssidae family include the highest diversity of mandatory hematophagous endoparasites of the respiratory system of birds. In general, these mites cause no significant lesions, except Sternostoma tracheacolum that invades the trachea, lungs and air sacs and may compromise breathing in birds. This study reports the death of a Belgian canary (Serinus canaria domestica) due to the parasitism by S. tracheacolum with an aggravating and concurrent pododermatitis infection. Case: A Belgian canary from a commercial bird flock, in which a high mortality rate had lately been recorded, was submitted to necropsy. Multiple blackened foci (1.0 mm in diameter) present in the trachea and the air sacs were subsequently identified as Sternostoma tracheacolum mites. Microscopically, there were diffuse and moderate infiltrates of lymphocytes, plasma cells, macrophages and heterophils within the tracheal submucosa and areas of fibrosis and osseous metaplasia of the tracheal cartilage. In the air sacs, there were multiple yellowish-brown foci of caseous necrosis, which were surrounded by inflammatory infiltrate of macrophages and multinucleated giant cells. In the lungs, there were foci of caseous necrosis surrounded by macrophages. In the tracheal lumen, mites sections were observed. Clusters of nucleated erythrocytes and brown granular pigment were seen within the longitudinal section of the mites. Prussian blue (Perls) special staining evidenced no hemosiderin content in the mite's tissues, in which no melanin could be detected, as well. Discussion: The parasitism by S. tracheacolum in canaries was first described in South Africa. In such cases, the mite induced clinical respiratory disease and killed the birds. Subsequently, reports of parasitism by these mites included several additional bird species, of which, Cockatiel (Nymphicus hollandicus) has been the most frequently affected and there are only a few reports of the condition in canaries. Clinically, hosts have difficulty breathing, exercise intolerance, coughing and sneezing. Depending on the severity, infection can persist for months or lead to death by suffocation or weakness. Clinical signs and death are related to the appearance of the lesions induced by the mites. Mite eggs are deposited in the lungs and the larvae hatch soon after oviposition. After the first meal, the female protonymph migrates to the posterior parabronchia, while the male protonymph remains in the lungs, where it completes the development. The adult mites full of eggs tend to occupy the parabronchia, the syrinx and the trachea. The negative results on Prussian blue and melanin bleach methods indicate that the dark pigment present within the tissues from the mites is neither hemosiderin nor melanin, respectively. In parasitism due to Plasmodium sp. (malaria), hemozoin, an iron-containing pigment associated with erythrocytic changes induced by the protozoan, has not been detectable by the Prussian blue staining. It is suggested that the dark color observed in the mites in this study could be associated with a similar pigment. The clinical respiratory diseases in birds are generally nonspecific. The paper focuses on the importance of the confirmation of the diagnosis by the necropsy and histopathological examinations, as well as on the characterization of this respiratory parasitic disease of birds.

Parasitism by the mite sternostoma tracheacolum in the respiratory system of a Belgian canary (Serinus canaria domestica) / Parasitismo pelo ácaro de sistema respiratório Sternostoma tracheacolum em um canário belga (Serinus canaria domestica)

Background: The nasal mites of the Rhinonyssidae family include the highest diversity of mandatory hematophagous endoparasites of the respiratory system of birds. In general, these mites cause no significant lesions, except Sternostoma tracheacolum that invades the trachea, lungs and air sacs and may compromise breathing in birds. This study reports the death of a Belgian canary (Serinus canaria domestica) due to the parasitism by S. tracheacolum with an aggravating and concurrent pododermatitis infection.Case: A Belgian canary from a commercial bird flock, in which a high mortality rate had lately been recorded, was submitted to necropsy. Multiple blackened foci (1.0 mm in diameter) present in the trachea and the air sacs were subsequently identified as Sternostoma tracheacolum mites. Microscopically, there were diffuse and moderate infiltrates of lymphocytes, plasma cells, macrophages and heterophils within the tracheal submucosa and areas of fibrosis and osseous metaplasia of the tracheal cartilage. In the air sacs, there were multiple yellowish-brown foci of caseous necrosis, which were surrounded by inflammatory infiltrate of macrophages and multinucleated giant cells. In the lungs, there were foci of caseous necrosis surrounded by macrophages. In the tracheal lumen, mites sections were observed. Clusters of nucleated erythrocytes and brown granular pigment were seen withi

Background: The nasal mites of the Rhinonyssidae family include the highest diversity of mandatory hematophagous endoparasites of the respiratory system of birds. In general, these mites cause no significant lesions, except Sternostoma tracheacolum that invades the trachea, lungs and air sacs and may compromise breathing in birds. This study reports the death of a Belgian canary (Serinus canaria domestica) due to the parasitism by S. tracheacolum with an aggravating and concurrent pododermatitis infection.Case: A Belgian canary from a commercial bird flock, in which a high mortality rate had lately been recorded, was submitted to necropsy. Multiple blackened foci (1.0 mm in diameter) present in the trachea and the air sacs were subsequently identified as Sternostoma tracheacolum mites. Microscopically, there were diffuse and moderate infiltrates of lymphocytes, plasma cells, macrophages and heterophils within the tracheal submucosa and areas of fibrosis and osseous metaplasia of the tracheal cartilage. In the air sacs, there were multiple yellowish-brown foci of caseous necrosis, which were surrounded by inflammatory infiltrate of macrophages and multinucleated giant cells. In the lungs, there were foci of caseous necrosis surrounded by macrophages. In the tracheal lumen, mites sections were observed. Clusters of nucleated erythrocytes and brown granular pigment were seen withi