We examined worker reproduction in queenless and queenright Apis cerana colonies to determine if they are parasitized by workers from other nests. The results demonstrate that 2-6% of workers in queenright colonies are from another nest (non-natal), but these workers are not statistically more likely to have activated ovaries than natal workers, and are therefore unlikely to be active parasites. However, in queenless colonies we found a significant difference between the proportion of non-natal (72.7%) and natal (36.3%) workers with activated ovaries. Non-natal workers also had significantly higher reproductive success than natal workers: 1.8% of workers were non-natal, but these laid 5.2% of the eggs and produced 5.5% of the pupae. Unlike A. florea, the proportion of non-natal workers does not increase in queenless nests.