But you can't do that I hear everyone cry..He's got two names and only one picture..Damn right, because the differences between the two insects are very small and it takes someone with experience to be able to differentiate between them. However, when I have finished you'll all be able to do it...identify them I mean..!

The adults of both species, can be distinguished by head shape, eye and body size, and colour. In the merchant grain beetle the eye diameter is larger than the temple region behind the eye, and the head is rectangular. The sawtoothed grain beetle, in contrast, has smaller eyes and a more triangular shaped head. The merchant grain beetle is somewhat larger and darker brown. Because both species are approximately 1/10 inch long, the larger size of the merchant grain beetle is difficult to assess in the grain bin. The most descriptive characteristic of both species is the six saw-like teeth found on either edge of the pronotum.

The habits and development of the two species are similar. The merchant grain beetle, however, is less cold tolerant and lays only about one-half to two-thirds as many eggs as does the sawtoothed grain beetle. The adult merchant grain beetles are strong fliers and may originate from other areas; they also are introduced into new grain from contaminated grain. The adults of the sawtoothed grain beetle, on the other hand, cannot fly and must be introduced from contaminated grain. An added help in identification is that the merchant grain beetle tends to prefer food sources which are higher in oil content such as nuts or copra.

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