Habitat selection was studied in two rhinolophid (Chiroptera) species, Rhinolophus mehelyi and R. euryale, breeding in the same roost in south-west Spain. The first analysis of habitat selection by R. mehelyi is provided, and the hypothesis explored that despite their close relatedness, in sympatry the two bat species showed different habitat preferences. For both species, the least preferred habitats were open habitats such as scrubland, grassland and arable land. As found elsewhere, R. euryale preferred broadleaved woodland. In addition, R. mehelyi also foraged in habitats characterized by loose trees, such as the ‘dehesa’, a semi-natural oak savanna. The progressive disappearance of the dehesa, jeopardized by land-use change, may not harm R. euryale, but could represent a threat to R. mehelyi, which would then be restricted to dense woodland, possibly competing with other bat species, including R. euryale. To conserve both species, the maintenance of a variety of wooded habitats of differing density is recommended.

Echolocation calls of 10 species of rhinolophid and four species of hipposiderid bats were recorded in China. Close negative relationships were found within Rhinolophidae and Hipposideridae between call frequency and ear length. Multiple regression and residual analysis were used to evaluate the influences of forearm length and ear length on call frequency and ear size. Ear length proved to be a more important morphological parameter influencing the call frequency in rhinolophids but not in hipposiderids. Ears are largely shaped by echolocation calls in both families. The influence of body size on ear size was significant in rhinolophids but not in hipposiderids, and the enlarged ears of rhinolophids correlated with the lower frequencies that rhinolophids used relative to larger body size.

Estimates of insectivorous bat diversity in the Palaeotropics have largely been hampered by the lack of long-term studies employing appropriate capture techniques. Using a variety of trapping methods, 45 insectivorous bat species were captured in approximately 3 km2 of primary dipterocarp rain forest in Malaysia over 8 y. The cumulative site list for Kuala Lompat Research Station, Krau Wildlife Reserve, now stands at 51 insectivorous species. Although this is likely still not a complete list, it is already one of the most species-rich in the world. We attribute much of our success in recording this diversity to the extensive use of harp traps. Of the 45 species, 38 were captured in an intensive harp-trapping programme (> 1030 harp-trap nights) of the forest interior (22 species exclusively so). Insectivorous bats of the forest interior are thus a key component of Old World bat diversity, particularly in South-East Asia, and are dominated by taxa capable of detecting and capturing prey in cluttered environments (Hipposideridae, Rhinolophidae, Kerivoulinae and Murininae).