How Aphids Feed on Healthy Plants

Ever wondered how aphids find and feed on healthy, high Brix plants?

Aphids use visual, olfactory, and gustatory cues to find plants and evaluate their suitability. When they find plants that meet these requirements, they pierce the tissue and allow sap high in sugar to flow into their bodies, where many enzymes break them down, along with proteins and amino acids. However, special bacteria produce many amino acids in their bodies.

Plants have defenses against aphids, including the production of compounds that are repellent or toxic, as well as those that attract predators and parasites. For aphids to be successful, they suppress the plant immune system to some degree, and the more aphids produced in a colony, the great this effect magnifies. Plants co-evolved with aphids for many millions of years before even flowering plants existed. So they also have their own immune responses to detect and neutralize aphid suppressants. However, they are not always successful as this comes down to genetic capability on an individual basis. Aphids are also often vector viruses that have many disabling effects of crippling plant development.

Despite this, in certain cases, aphids can actually be beneficial mutualistic agents to their plant hosts. In natural settings, those plants pay a “sugar tax” for their attraction of guard ants that protect them from harm by receiving their sugary waste called honeydew. Certain ant species will disrupt or kill herbivores that would cause even greater damage to the plant than the aphids.

In the past, the sugar-feeding ability of aphids has been under scrutiny, but research from insect physiologists like Dr. Angela E. Douglas shed light on the truly amazing digestive capacity of aphids! Studies have shown that aphids can feed on the sugar content of up to 34% Brix. The presence of sugar has a stimulating effect that encourages more feeding than lower levels, which other piercing insects like leafhopper relatives also share.

Check out the attached video https://youtu.be/LcZhHNqE6WA for more information about aphid feeding on high Brix plants!