What plants use insects for protection?

Written by
Tina Carter
Reviewed by
Prof. Martin Thorne, Ph.D.Through mutualistic relationships, plants engage in strategic partnerships with insects, providing them with food or shelter (the advantage of the plant) in exchange for defense (the advantage of the insects). These partnerships allow plants to outsource defence (and conserve energy) while insects procure necessary nutrients. This effective cooperation exemplifies complex ecological techniques separate from basic survival methods.
Acacia Trees & Ants
- Provide hollow thorns for ant colonies
- Secrete nectar from extrafloral nectaries
- Ants attack herbivores chewing on leaves
Macaranga Shrubs & Ants
- Develop hollow stems as ant housing
- Produce food bodies rich in lipids
- Ants prune competing vines around host
Grasses & Endophytic Fungi
- Host fungi within their tissues
- Fungi produce insecticidal alkaloids
- Protects against aphids and caterpillars
Passion Vines & Butterflies
- Provide larval food for Heliconius
- Butterflies suppress competing pests
- Egg mimicry deters other butterflies
These relationships operate on precise resource exchanges. The Acacia trees devote 15% of their energy to structures for feeding the ants. The shrubs in the genus Macaranga develop waxy runways, thus preventing the non-protective insects from gaining access to the nectar. The plants employ specialized security guards and compensate them through architectural modifications.
Farmers also manage these natural systems for sustainable pest control. Coffee plantations purposely cultivate ant colonies that lower damage by caterpillars by fifty percent. Ranchers grow endophyte-charged fescue to reduce pesticide use. These strategies conserve the ecological balance of nature while obtaining a very substantial cost reduction in chemicals.
These associations illustrate evolutionary precision. In the presence of ant colonies, Acacias decrease nectar production to limit free riders. Passion vines adjust patterns of egg mimicry in different geographic areas. Such adaptations exemplify that plants proactively engage with insects to manage local challenges.
Research shows these interactions can be remarkably complex. Evidence shows that plants can recognize protector ants through chemical signatures. There is also work showing that fungi are capable of adjusting their production of liquid alkaloids in response to herbivore pressure. These studies illustrate ecological complexity and various ways in which nature's security network is unwinding.
Read the full article: 9 Plant Defense Mechanisms Explained