We report boring activity of larval Lutrochus germari Grouvelle, 1889 and Stegoelmis sp. in submerged woody debris and describe the resulting grooves and faecal pellet production. This ability of the larvae was shown by three types of evidence: 1) examination of collected woody debris, 2) rearing of larvae and 3) gut content analysis. The larvae excavated galleries deep into the submerged woody debris. This is the first record of gallery-forming behaviour in submerged woody debris by aquatic beetles, adding larval Lutrochus germari and Stegoelmis sp. to the list of borers in Neotropical aquatic systems.
Faecal pellets; galleries; grooves; mining; xylophages
