A sample of chigger mites from bat hosts collected in the Balearic Islands (Western Mediterranean Sea) is found to include two species. These are the first records of bat-infesting chiggers identified to species in Spain. Chiggers collected from Pipistrellus kuhlii (Kuhl) in Menorca are identified as Oudemansidium komareki (Daniel et Dusbábek, 1959); this species, which was known from Austria, Bulgaria, Romania, Slovakia, Moldova, Crimea, and Azerbaijan, is recorded for the first time in Spain. Chiggers collected from Plecotus austriacus (Fischer) in Formentera are identified as Trombicula knighti Radford, 1954, which was insufficiently described from a bat in Yemen and known only from its type locality. We transfer this species to the genus Trisetica Traub et Evans, 1950 and provide its re-description based on paratypes and the material from the Balearic Islands. The species Sasatrombicula (Rudnicula) balcanica Kolebinova, 1966 is synonymised with T. knighti. One species closely related to T. knighti, Trisetica aethiopica (Hirst, 1926), which was recorded in Ghana, Uganda, South Sudan, and Madagascar, is re-described on the basis of its syntype deposited in the Natural History Museum, London, UK. This specimen is designated as lectotype.
Several species of the genus Pipistrellus (Vespertilionidae) store spermatozoa for prolonged periods prior to ovulation, but the reproductive strategy used by Pipistrellus kuhlii remains unknown. In order to investigate the prevalence of sperm storage in the bats of this genus we documented endometrial sperm storage in the uterus of two female Pipistrellus kuhlii collected during mid-December in western Iran. The uteri were distended with densely packed spermatozoa, those at the periphery exhibiting perpendicular orientation toward the endometrum. This orientation, together with the fact that copulation is unlikely to occur at this time is used to infer that P. kuhlii stores sperm over the winter.