Intraspecific variation in the strength of density dependence in aphid populations

• Published in: Ecological entomology 2004-10, Vol.29 (5), p.521-526
• Main Authors: Agrawal, A.A, Underwood, N, Stinchcombe, J.R
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Aphididae; Aphidoidea; Aphis nerii; Asclepias syriaca; Biological and medical sciences; carrying capacity; Demecology; density dependence; density manipulation experiment; Fundamental and applied biological sciences. Psychology; Hemiptera; host plants; logistic population growth; logit analysis; milkweed; phytophagous insects; plant-herbivore interactions; plant-insect relations; population density; population dynamics; population growth; population models; population regulation; prediction; Protozoa. Invertebrata; statistical models; temperature
• ISSN: 0307-6946; 1365-2311
• DOI: 10.1111/j.0307-6946.2004.00635.x

1. Experimental evidence is presented for positive, negative, and no density dependence from 32 independent density manipulations of milkweed aphids (Aphis nerii) in laboratory and field experiments. This substantial variation in intraspecific density dependence is associated with temperature and host-plant species. 2. It is reported that as population growth rate increases, density dependence becomes more strongly negative, suggesting that the monotonic definition of density dependence used in many common population models is appropriate for these aphids, and that population growth rate and carrying capacity are not directly proportional. 3. For populations that conform to these assumptions, population growth rate may be widely applicable as a predictor of the strength of density dependence.