Biological activity of the mite Sancassania sp. (Acari: Acaridae) from bat guano associated with the pathogenic fungus Histoplasma capsulatum

Mites and the mammal pathogenic fungus Histoplasma capsulatum are the major components of bat guano microbiota. Interactions between mites and H. capsulatum were evaluated under laboratory conditions. Acarid mites, mainly Sancassania sp., were the most abundant microarthropod in the sampled guano of the Mexican bat Tadarida brasiliensis mexicana and, based on its morphology, Sancassania sp. was similar to the cosmopolitan species Sancassania sphaerogaster. The mycophagous and vectoring activities of this mite were tested for H. capsulatum and two other fungal species, Sporothrix schenckii (pathogenic) and Aspergillus sclerotiorum (non-pathogenic). S. ca. sphaerogaster was able to reproduce in H. capsulatum and S. schenckii colonies, multiplying in great numbers under controlled fungal mycelial-phase culture conditions. H. capsulatum colonies were completely destroyed after 14 days of in vitro interaction with mites. In contrast, S. ca. sphaerogaster did not reproduce in A. sclerotiorum cultures. S. ca. sphaerogaster was found vectoring H. capsulatum, but not the two other fungal species studied.

Dispersão de Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) em trigo armazenado, sob condições artificiais / Dispersion of Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) in stored wheat, under artificial conditions

A habilidade de dispersar é fundamental para o êxito de um inimigo natural em situações de armazenamento de grãos. O objetivo deste trabalho foi avaliar a capacidade do ácaro Acarophenax lacunatus (Cross & Krantz) se dispersar e localizar o hospedeiro Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) em uma massa de grãos. O experimento consistiu na liberação de fêmeas fisogástricas de A. lacunatus na superfície de uma massa de grãos de trigo, no interior de frascos de vidro, os quais continham placas de Petri (5 cm de diâmetro) com 20 adultos de R. dominica, em diferentes profundidades (4, 8, 12, 16 e 20 cm da superfície). As placas de Petri foram cobertas com organza para evitar o escape dos insetos. A dispersão da progênie dessas fêmeas fisogástricas foi avaliada 10, 20 e 30 dias após o início dos experimentos. Os ácaros foram capazes de se dispersar, sendo encontrados em todas as profundidades e em todos os períodos avaliados. Entretanto, o número de A. lacunatus diminuiu à medida que a profundidade aumentou, com altos valores observados nas profundidades iniciais após 20 e 30 dias de armazenamento. É possível que avaliações conduzidas em períodos maiores que 30 dias da liberação do parasita possam demonstrar um aumento no parasitismo em profundidades maiores. Os resultados indicam que A. lacunatus se dispersa ativamente, até 20 cm de profundidade, sem o auxílio de um hospedeiro para a foresia.

Ability to disperse is fundamental for a successful natural enemy in a stored grain environment. The objective of the present work was to assess whether the mite Acarophenax lacunatus (Cross & Krantz) disperses in a grain mass to locate its host Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae). The experiment was based on the release of physogastric females of A. lacunatus on the surface of glass containers containing Petri dishes with 20 adults of R. dominica at different depths (4, 8, 12, 16 and 20 cm). The Petri dishes were covered with voil to prevent insect escape. Dispersion of the progeny of these physogastric females was assessed 10, 20 and 30 days after the beginning of the experiment. The mites were able to disperse and they were observed at every depth and at every period of assessment. Nonetheless, the number of A. lacunatus decreased with the increasing depth, with highest values observed at the lowest depths after 20 and 30 days of storage. It is possible that evaluations conducted in periods longer than 30 days of the parasite release could demonstrate an increase in parasitism at higher depths. The results indicated that A. lacunatus actively disperse for up to 20 cm on its own, without the assistance of its host for phoresy.

Notes on the biology of Amblyomma dissimile Kock, 1844 (Acari: Ixodida) on Bufo marinus (Linnaeus, 1758) from Brazil

Amblyomma dissimile is a common ectoparasite of cold blooded animals and is an accidental ectoparasite of some wild mammals. Details of the biology of specimens from the State of Amapá were studied in the laboratory in a humidity chamber at an average environmental temperature of 19.5 §C, using Bufo marinus as host for the time in Brazil. We also report the first record of this species in the State of Minas Gerais

Preliminary investigations on transmission and life cycle of the ear mites of the genus Raillietia trouessart (Acari: Gamasida) parasites of cattle

The life cycle of ear mites of the genus Raillietia Trouessart consists of egg, larva, proto-and deutonymph and adult. The proto-and deutonymph are free living, non feeding instars. The teneral adult is the transfer stage. The minimum period required for completion of the life cycle is approximately eight days