What is enough? – Issue #105

Hello Explorer,

Last week I shared about the complexity involved in when an ant colony is dead, and this week I want to continue in this topic, but with a specific focus on pest management. As you might already know ants are a serious pest, both in agriculture and in homes and buildings.
In agriculture ants usually do not damage the crop themselves, but they farm a lot of different sap sucking pests for the sweet honey dew they produce. Ants will protect the sap sucking pests and even move them to the best places on the plant, so that they produce more honeydew, which is often on the part of the crop that is to be harvested. Thus, the control of ants is of utmost importance in agriculture.
In homes and buildings they are often only a nuisance pest, which bothers people without having a severe negative impact. No, the ants that got into your sugar and are now floating in your coffee won’t kill you, it is just a little addition of protein to your coffee 😉.
The main issue for pest control is, what is enough control? Complete elimination?  Or just enough to stop them from causing havoc?
In homes the control might be considered enough when you stop finding them in your coffee in the morning, but they are still around, just not as noticeable. Or it might be complete elimination if they move into food cupboards. Also, in homes it becomes a challenge, as many of the ant species that do enter homes do so much more in the dry season, as they are in search of water, and the running water from your taps are more than enough to sustain and satisfy them. This would mean that the level of control exerted during wet and dry seasons will differ substantially. In homes the amount of control is let over to the homeowner and what they are willing to spend to get rid of the ants.
In agriculture, however, there is much more to consider. Absolute elimination is an option, but it is an expensive and time-consuming option. Also, absolute elimination would open ecological space for another species to move in and occupy, which might be much worse than the ants.
The control level aimed for in agriculture is known as the economic threshold or economic injury level. Below this threshold it is more expensive to control a pest, like ants, than the damage they are causing. Above this threshold the pest will cause more damage than what it will cost to control them.
The problem with ants, however, is that they do not directly cause damage to the crops, so to determine their economic threshold is very complex. Consider this for a moment. If you have three sapsucking pests in your crop, all three below the economic threshold, control won’t be required but, when ants are present, they change the dynamics and potentially even lower the economic threshold for the sapsucking species. On the other hand, ants are also beneficial in agriculture due to their ecosystem services like soil engineering, erosion control, predation and pest control. Yes, they control some pests through predation and aid other pests by farming them.
Thus, the challenge of determining the economic threshold for ants are complex, multilayered, and every choice influences something else in the agricultural ecosystem. To further complicate the issue of ants in agriculture, consider the fact that some ant species are purely predaceous, and will only be beneficial to the crop through pest control, while other species are very closely associated with honeydew producing insects rarely predating on pest species.
The main challenges of controlling ants in an agricultural setting is thus determining what species are present, what they are doing in the agricultural ecosystem, how they are impacting pests (positively or negatively), what the balance is between beneficial and pest ant species, what is the economic threshold of each ant species, and does the economic threshold change with seasons as the ants diets change according to the seasons?
Striking a balance between controlling ant populations and preserving their ecological roles is crucial for sustainable pest management. While reducing ant numbers below the economic threshold is essential to minimize crop damage, it's critical to avoid pushing them past the point of recovery, leading to colony collapse. Attaining this balance requires in depth knowledge of the ecology, interactions, colony structures, and basic biology of the ants.
Have you considered the complexities of controlling ants in an agricultural setting before? What ethical considerations should be taken into account when controlling ants that have such vast ecological impacts?

If you would like to send me a message with your answers, feel free to do so on Instagram or Twitter @abugmanslife or via email to [email protected].