The effects of dietary nitrogen on reproductive development in the female boll weevil, Anthonomus grandis

ABSTRACT. The role of dietary nitrogen in reproductive development was investigated in the female boll weevil, Anthonomus grandis (Boh.)(Coleoptera: Curculionidae). Artificial diets were employed containing 1.7%, 2.6% and 4.0% N. Each diet was labelled with a ¹⁴C-amino acid mixture and standardized relative to cpm and N per mg of diet dry weight. Egg production, diet consumption, nitrogen consumption and nitrogen utilization were measured by recovering the cpm in the faeces, ovaries plus eggs and the carcass.
Females given the 4% N diet initiated oviposition on day 4 with maximum egg production of 11 eggs/day/female occurring on day 6. Females on the 2.6% N diet also initiated oviposition on day 4, but the time necessary to reach maximum egg production was extended. Egg production by these females eventually equalled the total production of the group on the 4% N diet. This was achieved by consuming more diet per female and dedicating a higher percentage of the absorbed diet to egg formation. With the 1.7% N diet, females showed both a delay and a decrease in total egg production because of reduced feeding and a reduced commitment of consumed nutrients to oöcyte maturation.
Switching dietary nitrogen concentrations after the initiation of oviposition resulted in changes in consumption and reproductive allocation within 48 h.