A group of scientists established over a year ago that chimpanzees self-medicate by using crushed insects to treat wounds for themselves and for others. Now a separate study shows that Formica fusca ants turn to aphids as medicinal helpers when illness strikes.
The Austrian, Dutch, German, and Finnish researchers published their findings in Biology Letters. They report that these common ants seek out aphids that accumulate hydrogen peroxide in their surroundings to help combat fungal infections.
To determine if this self‑medication behavior exists, the researchers collected Formica fusca from a rural area in Finland and brought the ants to a lab setting for controlled testing.
In the experiment the ants were exposed to a fungal challenge. Infected and uninfected ants were then offered two diets: a plain honey and agar mix and a honey and agar mix with varying amounts of crushed aphids added for medicinal value.
Results showed that uninfected ants preferred the standard honey‑agar mixture without aphids. In contrast, infected ants split their choices equally between the standard diet and the aphid‑enhanced option, suggesting a targeted self‑medication response.
During observations the researchers noted that after the fungal infection cleared, infected ants returned to the normal diet without aphids.
The scientists concluded that these ants do practice self‑medication and that the quantities consumed during illness appear to be beneficial for self‑healing.
Complex nutritional strategy
A diet consisting solely of aphids would likely be harmful due to hydrogen peroxide toxicity, while too little aphid content would fail to support immune defenses. The team emphasizes that healthy sick ants still need a balanced intake of nutrients to sustain immune function.
The researchers plan to study how ants behave in their natural environments when ill and how aphids contribute nutrients or compounds that might bolster ant health during infections.
The biologists and zoologists behind the study say that regulating animal food intake to fight pathogens is gaining attention. Prior work has shown how isolated nutrients affect behavior, but proving natural drug sources in the wild remains a frontier.
Thus they examined whether formica fusca workers exposed to a fungal threat modify their diet by incorporating more aphid fortified foods. The aim was to see if this adjustment could reduce death rates and lessen disease impact.
They note that the benefit depends on access to a diverse diet. Aphids may provide valuable nutrients or compounds, but they are part of a larger, intricate nutritional system where costs and benefits must be managed.
Deliberate dietary shifts
The study tracked how colonies altered their food preferences in response to pathogen exposure. A noticeable shift toward aphid fortified food occurred between day four and day six, aligning with the period of peak pathogen mortality, and then shifted back toward the standard mix as the infection subsided.
The researchers interpret this as a conscious and rapid adjustment in nutrient demand during the acute phase of illness. They suggest that pathogen pressure prompts a dynamic, strategic response in colony feeding behavior.
Looking ahead, the team wants to explore how pathogens might influence interactions between aphids and ants, including the specific nutrients and compounds transferred from aphids and their potential effects on infections in ants.
Their work raises questions about the evolution and persistence of reciprocity between ants and their aphid partners and whether this relationship provides an additional shield against pathogens.
Natural medicine and ecosystem health
Interviews with researchers reveal that discovering how animals use diet to balance immune responses can illuminate why diverse ecosystems remain healthier against disease threats that continue to challenge wildlife and, possibly, humans.
Hydrogen peroxide is a pale blue liquid with strong oxidizing properties. It acts as a disinfectant and antiseptic and serves as an oxidant used in various applications, including laboratory work and environmental treatments. In the context of ants and aphids, hydrogen peroxide is a natural component in the compound mix that contributes to fungal suppression.
Reference: Royal Society publishing. The article discusses a broader view of how natural factors help animals cope with infections.
Further reading on how natural food webs influence health outcomes can broaden understanding of disease resistance in wildlife and guide conservation efforts.