Timberworms, primitive weevils, straight snouted weevils

Code QCAM0000

Only one genus of brentids may routinely occur in aquatic samples: Nanophyes, a species of which has been found mining the stems of Ludwigia (Onagraceae), an aquatic plant. This genus may be readily separated from most individuals of the similar aquatic curculionid subfamily Erirhininae by the spiracles - most erirhininids have the spiracles drawn out into paired dorsal spines, a character not occurring in the Brentidae. When such spines are not apparent, Nanophyes larvae can be distinguished from erirhininid by the lack of stemmata (erirhininids have 1-2 pairs) and the 1-segmented labial palp (2-segmented in Erirhininae). Note that the key only separates truly aquatic brentids and curculionids - it may not work for terrestrial individuals that have occurred incidentally.

Other characters of Nanophyes include the lack of legs and curled, grublike abdomen. Body largely unsclerotised. Antenna of one reduced membranous segment, bearing a sensory appendage and a few minute setae. Abdomen lacking urogomphi, hooks, gills, pygopods or other appendages.

Most Brentidae (Polyphaga: Curculionoidea) are terrestrial but as discussed above, species of Nanophyes are found associated with aquatic plants. Overall, around 200 species of brentids in 5 subfamilies occur in Australia.

References:

Anderson, D.M. (1991) Curculionidae (Broad Sense) (Curculionoidea) pp. 592-593. In: Stehr, F.W. (ed.) Immature Insects. Volume 2. Kendall/Hunt Publishing Company, Dubuque, Iowa.

Lawrence, J.F. and Britton, E.B. (1991) Coleoptera. pp. 543-683. In: CSIRO, Insects of Australia. Volume 2. Melbourne University Press, Carlton, Victoria.