Population Ecology

, Volume 47, Issue 2, pp 127–136

Factors affecting the proportion of sterile soldiers in growing aphid colonies

Original Article

DOI: 10.1007/s10144-005-0218-z

Cite this article as:
Aoki, S. & Imai, M. Popul Ecol (2005) 47: 127. doi:10.1007/s10144-005-0218-z


The proportion of sterile soldiers in an aphid colony is positively correlated with colony size. Assuming logistic growth of the aphid colony, Aoki and Kurosu (Insect Soc 50:256–261, 2003) presented an inequality that determines, for any colony size, whether a soldier or a reproductive will be added to the colony. To put it in words, if the marginal defensive efficacy of a soldier, multiplied by the number of reproductives, is larger than the mean productivity of reproductives without defense by that soldier, the soldier will be produced; if not, a reproductive will be produced. Based on Aoki and Kurosu’s inequality, we carried out simulations to determine whether the proportion of soldiers increased with colony size. Given a constant level of depredation per aphid and a constant number of predators, proportion of soldiers continued to increase with colony size unless a single soldier was very effective or unless carrying capacity was very large. Given a constant number of nongluttonous predators and a decreasing level of depredation per aphid, proportion of soldiers soon began to decrease after a peak. However, given an increasing number of nongluttonous predators to keep a constant level of depredation per aphid, proportion of soldiers again continued to increase. These results confirmed the argument that the proportion of soldiers can increase with colony size under a wide range of realistic assumptions.


Carrying capacityLogistic modelOptimal defensePseudoregmaSimulation

Copyright information

© The Society of Population Ecology and Springer-Verlag Tokyo 2005

Authors and Affiliations

  1. 1.Faculty of EconomicsRissho UniversityJapan