The relationship between ants and mold is more intricate than a simple preference. While it might seem that ants are drawn to mold, their interactions with these fungi are quite varied, ranging from active cultivation to deliberate avoidance. Ant behaviors are shaped by environmental conditions and available resources.
Mold as an Ant Food Source
Mold can serve as an indirect food source for many ant species. Some ants consume microorganisms (bacteria or fungi) that flourish on mold, which break down the mold and make its nutrients accessible.
A more direct and specialized relationship exists with fungus-growing ants, such as Attine ants, including leaf-cutter ants. These ants actively cultivate specific fungi in their nests, using plant material as a substrate to grow their fungal gardens. The ants do not directly eat the leaves; instead, the cultivated fungus digests the plant material, and ants feed on the fungal structures, their primary food source, especially for larvae.
Mold’s Role in Ant Habitats
Mold often indicates the presence of moisture, a significant factor in ant habitat selection. Carpenter ants, for example, do not consume wood, but they excavate tunnels in damp or decaying wood to create their nests. Mold growth often signifies that wood has been softened by moisture, making it easier for these ants to tunnel and establish colonies.
Similarly, moisture ants thrive in wet and humid environments and commonly nest in water-damaged or decaying wood. Their presence frequently signals an underlying moisture problem in a structure. These ants may also construct “carton” nests from a mixture of soil, chewed wood, and ant secretions.
Molds Ants Actively Avoid
While some molds can be beneficial, many types are harmful or deterrents to ants. Certain molds produce mycotoxins, which can be toxic and even deadly to ants. An example is Aspergillus flavus, a pathogenic species known for producing potent mycotoxins.
Ants exhibit hygienic behaviors to protect their colonies from harmful fungi. They engage in self-grooming and social grooming, where nestmates remove fungal spores from each other to prevent infection. Ants may also attempt to suppress mold growth by covering it with substrate or removing moldy food items from their nests. White fluffy molds are detrimental to ant health.
Ants, Mold, and Your Home
If ants are observed near mold in a home, it often points to an underlying moisture issue. Ants, especially carpenter ants and moisture ants, are attracted to the damp conditions that allow mold to flourish. They seek out water sources and soft, water-damaged wood for nesting, where mold also thrives.
The presence of ants near mold can serve as an indicator to investigate potential water leaks or areas of high humidity within the structure. Addressing the source of moisture is a primary step in resolving both the mold problem and the ant infestation. Ants can also carry various microorganisms, including fungi and bacteria, on their bodies, potentially transferring them to surfaces as they forage.