An autonomous recording unit (ARU) is a self-contained audio recording device that is deployed in marine or terrestrial environments for bioacoustical monitoring.
Katydid crickets, for example, communicate by sounds with frequencies higher than 100 kHz, far into the ultrasound range.
These birds were formerly considered subspecies of the Common Chiffchaff but separated (Clement & Helbig, 1998; Sangster et al., 2001) due to their morphological, bioacoustical, and mtDNA sequence differences (Helbig et al., 1996).
In 1966 he wrote his thesis "The taxonomic and ecological analysis of Sem. Dermestidae (Coleoptera)" and in 1980 his PhD on insect bioacoustics.
Both the western and the now extinct eastern (Phylloscopus canariensis exsul) subspecies of the Canary Islands Chiffchaff were formerly considered subspecies of the Common Chiffchaff but were separated (Clement & Helbig, 1998; Sangster et al., 2001) due to their morphological, bioacoustical, and mtDNA sequence differences (Helbig et al., 1996).