Some simple polyols and related compounds were assayed by a filter paper method for the feeding-stimulative effect on the three species of cockroaches, Periplaneta americana, P. fuliginosa and Blattella germanica. Glycerol was further tested by a bait method for B. germanica. I. The results obtained by the filter method are as follows. 1) Glycerol is highly effective, but ethylene glycol, 1, 2-propanediol and 1, 3-propanediol are not. 2) The three hydroxyl groups in glycerol, therefore, seem to be essential for the strong activity of this compound. 3) Many compounds with neighboring three or more carbon atoms each of which has a hydroxyl group, especially sugar alcohols, are effective. However, there are also many ineffective stereoisomers among them, especially among sugars (Tsuji, 1965). 4) Therefore, not only the number of hydroxyl groups but the configuration of molecule is also one of the important factors which determine the effectiveness of the compound. 5) It is interesting to know that, a) among aldoses (pentoses and hexoses) Larabinose and D-galactose with the same configuration at C_2-C_3-C_4 were strongly effective for all or one of the three species, whereas other stereoisomers tested were not (Tsuji, 1965); b) glycerol can take all the imaginable arrangements in space of the three hydroxyl groups, and naturally can take the same arrangement of hydroxyl groups as at C_2-C_3-C_4 of L-arabinose; c) the same arrangement of hydroxyl groups as at C_2-C_3-C_4 of L-arabinose can occur more frequently in sugar alcohols than in corresponding aldoses, and many of the sugar alcohols tested were effective, whereas many of the aldoses tested were not effective; d) sorbitol which can take two sequencial sets of the same arrangement of hydroxyl groups as at C_2-C_4-C_4 of L-arabinose was exceptionally effective among the effective sugar alcohols. 6) One possible speculation is that glycerol, the effective sugar alcohols, and the effective aldoses stimulate the receptor of the cockroaches by combining with the same combining site which consists of sequencial sets of structures corresponding in some way to the arrangement in space of hydroxyl groups at C_2-C_3-C_4 of L-arabinose. 7) A few glycerides, including monoolein, triolein and tricaprin, are somewhat effective, though they have not three hydroxyl groups. In these glycerides, the cockroaches seem to respond to specific acyl groups in their structures. II. The results obtained by the poison bait method with the German cockroach show that glycerol is quite effective as a feeding-stimulant in practical poison baits, and is much more effective than maltose, the strongest feeding-stimulative sugar.
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