Effects of glucose‐supplemented diets on food intake, nymphal development, and fecundity of glucose‐averse, non‐glucose‐averse, and heterozygous strains of the German cockroach, Blattella germanica

Life history parameters were determined for glucose‐averse ( glu / glu ), wild‐type ( glu +/ glu +) and heterozygous ( glu / glu +) genotypes of Blattella germanica (L.) (Blattodea: Blattellidae) fed diets supplemented with glucose. Glu / glu nymphs consumed less glucose‐supplemented diet, gained less weight, developed slower and had a lower rate of survival than glu / glu nymphs fed the same diet without added glucose, or glu +/ glu + and glu / glu + fed either diet. Prior to formation of the first oötheca, female glu / glu consumed less glucose‐supplemented diet per day than glu +/ glu + and glu / glu +, which presumably delayed egg case production. Oötheca‐bearing glu / glu and glu / glu + females consumed less glucose‐supplemented diet than glu +/ glu + females. Despite a difference in female total diet intake, there was no effect of diet or genotype on fecundity. However, the intrinsic rate of increase ( r ) for glulglu on unsupplemented diet was less than that of glu +/ glu + and glu / glu +, suggesting that individuals with both glu alleles may be at a selective disadvantage in environments lacking diets containing glucose plus a toxicant.