Maternal and Paternal Nitrogen Investment in Blattella Germanica (L.) (Dictyoptera; Blattellidae) Available to Purchase

The investment of nitrogenous materials by female and male German cockroaches Blattella germanica (L.) into their progeny was examined. Adult females maintained on dog food invested 34 % of their dry mass and 26 % of their nitrogen into an ootheca during their first gonadotrophic cycle. Females maintained on a low-(5%) protein diet and injected simultaneously with [³H]leucine and [¹⁴C]hypoxanthine incorporated less [³H]leucine-derived radiolabel in their oothecae than those on a dog food diet (25% crude protein). Females on the lowprotein diet incorporated more [¹⁴C]hypoxanthine-derived material (primarily as [¹⁴C]urates) into their oothecae than they retained in their bodies. Stored [^L4C]urates were metabolized more readily by females on the low-protein diet. Oothecae obtained from females provided with an [¹⁵N]urate-amended diet contained at least four ¹⁵N-enriched amino acids, which supports the hypothesis that urates are utilized as a nitrogen resource in these insects.

Dietary effects on paternal investment were also found to be significant. Females fed a low-protein diet and their oothecae contained 63 % of the radiolabel made available to them at mating when paired with males injected simultaneously with [³H]leucine and [¹⁴C]hypoxanthine, whereas dog-food-fed females and their oothecae contained only 17 % of the total radiolabel made available to them at mating.