Nutritional regulation in nymphs of the German cockroach, Blattella germanica

Synthetic foods varying in protein-carbohydrate ratio and total nutrient co ncentration were used in food selection experiments to investigate the inge stive and post-ingestive regulation of macronutrients by male and female ny mphs of the German cockroach, Blattella germanica (L.) (Dictyoptera: Blatte llidae). For both nutrient imbalance and food dilution, food ingestion vari ed between treatments with the effect that nutrient ingestion was regulated . However, this mechanism was insufficient to compensate for some food dilu tion treatments. In those cases, the regulation of protein intake was prior itised over that of carbohydrate intake, and two additional regulatory resp onses were seen. Firstly, cellulose digestion supplemented shortfalls in di etary soluble carbohydrates, and secondly the feeding period within the sta dium was prolonged. These ingestive, post-ingestive and developmental respo nses were orchestrated in such a way that, in all treatments, nutrient gain approached similar levels, despite the variation in food properties. (C) 2 001 Elsevier Science Ltd. All rights reserved.