Food quality and quantity in relation to egg production in Locusta migratoria migratorioides

Abstract

Oöcyte development is not initiated when female Locusta migratoria migratorioides are fed on poor, low-protein Agropyron repens. Survival on this diet is improved by the provision of water and small quantities of lush A. repens. When maturing female locusts (with developing oöcytes), previously fed on lush grass, are provided with the poor-quality grass the rate of egg pod production is reduced and terminal oöcyte resorption is increased. The final percentage resorption and the possibility of oviposition is determined by the total quality of food during vitellogenesis. In poor-grass fed locusts the levels of ingestion and utilization are low and suggest that quantitative factors are likely to be critical. Quantitative studies show that the provision of gradually decreasing amounts of A. repens produces corresponding decreases in the rate of egg pod production and increases in terminal oöcyte resorption. When the quantity of food ingested is reduced, the rate of oöcyte development is first reduced, followed at lower levels of feeding by an increase in terminal oöcyte resorption. Ingestion of less than 80 mg (dry weight) of grass/female per day is insufficient to initiate oöcyte development in locusts whose somatic growth period is normal. The significance of these results is discussed.