Meeting Abstract
Since the 1970’s Oedaleus senegalensis has become and remains the most prominent pest of millet, a subsistence crop, in the Sahel region of Africa. A handful of studies have demonstrated that, unlike most herbivorous insects that are nitrogen (~protein) limited, some locust species prefer and perform better on carbohydrate-biased foods. We tested O. senegalensis nutritional preference and performance on foods varying in their protein: carbohydrate ratios. We ran experiments both in the laboratory, using artificial diets, and in the field where we modified the nutritional content of millet with two levels of fertilization using urea as a source of nitrogen. Our results show that, unlike predicted by the nitrogen limitation hypothesis, O.senegalensis prefers artificial food and millet leaves with a lower protein content. In the field, we found that locusts that were fed unfertilized millet lived longer than the ones fed millet grown with high or medium level of fertilizer. However, the mass of the eggs laid on the high fertilization treatment was higher than for the control plot that did not receive urea, suggesting a nutritional trade-off between lifespan and reproduction.
