Insect of the Week!

Aphis glycines
The Soybean Aphid

The soybean aphid, which is native to Asia, was first observed in the Midwest United States in 2000. Since then, it has spread though almost half of the US, and into Canada. Aphids suck sap from their host plants, and at high populations they can cause a significant decrease in soybean yield. The aphids can also transmit viruses into plants causing a further loss of yield.

The aphids overwinter on buckthorn. In the spring, their eggs hatch and the soybean aphid completes a couple generations of sexual reproduction on the buckthorn. Soon after, winged females (that are fertile without mating colonize soybean early in the summer. They deposit live young who are also female, as well as fertile, and after about a week this new generation reaches reproductive age. Eventually after about 15-18 generations winged aphids begin to emerge (still all females) and they migrate back over to the buckthorn, where males are produced and sexual reproduction can then occur again, after which eggs are laid for overwintering until the next summer.

This species is currently an interest to me because it is an important prey species for the multi-colored Asian lady beetle (Harmonia axyridis), another exotic species from Asia. The arrival of the soybean aphid may have facilitated the establishment of H. axyridis.

photo credit: Bob O'Neil (Purdue University)