The effects of selective logging on the diversity and species composition o
f moths were investigated by sampling from multiple sites in primary forest
, both understorey and canopy, and logged forest at Danum Valley, Sabah, Ma
laysia. The diversity of individual sites was similar, although rarefied sp
ecies richness of logged forest was 17% lower than for primary forest (unde
rstorey and canopy combined). There was significant heterogeneity in faunal
composition and measures of similarity (NESS index) among primary forest u
nderstorey sites which may be as great as those between primary understorey
and logged forest. The lowest similarity values were between primary fores
t understorey and canopy, indicating a distinct canopy fauna. A number of s
pecies encountered in the logged forest were confined to, or more abundant
in, the canopy of primary forest. Approximately 10% of species were confine
d to primary forest across a range of species' abundances, suggesting this
is a minimum estimate for the number of species lost following logging. The
importance of accounting for heterogeneity within primary forest and sampl
ing in the canopy when measuring the effects of disturbance on tropical for
est communities are emphasized.