Ants may seem like annoying insects, but these tiny creatures make a huge contribution to our ecosystem. They aerate soil, pollinate plants and spread their seeds. They are also a vital menu item for animals such as giant anteaters.
Researchers are increasingly using ants as indicators to gauge ecological restoration. A recent study showed that ants are responding to climate change in a similar way to plants.
1. Ants Help to Decompose Organic Waste
The decomposition of organic matter by ants helps break down complex compounds into simpler forms that can then be used to create nutrients for plant growth. Ants also help to distribute seeds, which improves soil fertility by mixing the layers of soil.
Ants are also important pollinators, and they can reduce weeds in agricultural systems. They also fulfill protective symbiotic relationships with many sap-feeding insects and plants, such as orchids and fruit trees.
In addition, ants are essential to the redistribution of nutrients within ecosystems. A recent study found that ants are crucial to the nutrient cycling process in tropical rainforests. This means that a decline in ant populations could have a negative impact on forest biodiversity and ecological function.
Like other poikilothermic ectotherms, ants are sensitive to temperature and can track large changes in ambient temperatures. They exhibit a thermal performance curve, where they rise to their thermal optima and then rapidly decline as the temperature becomes intolerable (Figure 2). As a result, ant diversity has been found to respond similarly to changing climates. However, these effects are less well understood at the community and macrogeographic scales. Therefore, more research is needed to understand how ant diversity will respond to rapid temperature increases.
2. They Help to Pollinate Plants
Despite their negative reputation as plant predators, ants are actually effective pollinators, especially for flowering plants like smokebush Conospermum. This is due to the fungus-growing bacteria in their guts, which are transferred to the flowers they visit, effectively fertilizing them.
However, early work suggests that many plants have adaptations to prevent ant pollination, such as slippery stems, sticky blossoms, or extrafloral nectaries (Hickman 1974; Rostas and Tautz 2011). Also, ants’ long legs, self-grooming behaviors, and limited movement as non-flying insects can reduce pollen viability (Domingos-Melo, Nadia, and Machado 2017; de Vega, Herrera, and Dotterl 2014).
Ants’ surprisingly effective dispersal of seeds enables new species to enter the ecosystem, potentially disrupting local nutrient and water dynamics and even establishing novel antagonistic relationships with their hosts (Lowe et al., 2000). Indeed, ants are one of the most successful and widespread introduced species in nature, with 19 invasive species recorded globally (Lowe et al., 2010).
Nevertheless, the ants of recovering environments such as those in Western Australia are marching on, eating, and reshaping ecosystems around them. And though restoring habitats maimed by mining or agriculture takes years, it’s clear that ants are remarkably quick to respond to changes in their environment.
3. They Help to Disperse Seeds
As ants scurry through their daily routines, they carry bits of plants and other animals back to their nests. This seemingly mundane behavior helps fertilize the soil and ensures that nutrients are recycled throughout ecosystems. Additionally, it has a major impact on dispersal of seeds.
Researchers have found that certain seed traits are more attractive to ants than others. Grass seeds, for example, tend to have long and narrow seed structures that provide a better “handle” for ants to grasp. The same holds true for myrmecochorous plants, which attract ants by releasing a sweet scent that lures them in for a snack.
Ants are also great indicators of the health of ecosystems. For instance, ant communities respond quickly and strongly to thermal gradients. This behavioral flexibility, combined with their ability to disperse seeds, may help them adapt to climate change.
As people around the world seek to rehabilitate damaged ecosystems, scientists are turning to ants as indicators of their success. This is because ants can tell us how effective conservation efforts are at restoring habitats. Ants also serve as a model for other species groups that are likely to be affected by ongoing climate change.
4. They Help to Control Pests
Ants are skilled predators that also act as effective insect controllers. They prey on a wide variety of other insects and, at the same time, help control pests that damage crops. Ants are a keystone species in many ecosystems and their abundance is highly correlated with biodiversity. Click here to learn about the biggest ant in the world!
Because ants are so prolific, they are important to the overall health of ecosystems and provide key services such as biological control, soil bioturbation, plant pollination and seed dispersal. Ants are also a vital food source for other organisms including reptiles, birds and mammals.
As climate change continues, we are beginning to understand the impact it may have on ant diversity and their many functions. For example, a recent study found that large temperature increases can cause ant communities to “tip over” their thermal performance curve — meaning they can no longer survive at a given environmental temperature.
Moreover, the eusocial nature of ants also impacts how they respond to climate change. Because ant colonies function in series-parallel, if one worker dies while on a foraging trip or defending their nest, the rest of the colony can continue to perform their duties. This is different from solitary organisms which must complete tasks sequentially.
5. They Help to Control Insects
Ants are one of the most abundant groups of animal species on Earth. As prey or predators, they have a significant influence on the trophic network of ecosystems. They also serve as a keystone in numerous mutualistic relationships with plants  as well as other organisms such as arachnids, reptiles (including toads, lizards and snakes), birds and mammals.
For example, some plant species use ants to disperse their seeds through a process known as myrmecochory. This is a widespread mutualism that benefits over three thousand plant species worldwide. Ants are able to disperse these seeds by consuming the fatty, nutrient-rich eliaosome and then moving or burying them.
As a result, ant-plant mutualisms provide important services such as pollination, weed control and soil bioturbation. This natural form of pest management allows farmers to reduce the need for chemical pesticides, which are harmful both to humans and the environment.
It’s therefore crucial to understand how these ecological processes will change with the ongoing climate changes. And it turns out that ants are a good indicator of these changes because they respond to temperature gradients very quickly and strongly. This means that if temperature increases drastically from a high starting point, ants may be more likely to “tip over” their thermal performance curve and enter the negative part of it.
6. They Help to Control Mosquitoes
While they may seem like a nuisance, ants’ tireless efforts to keep mosquitoes under control help ensure healthy ecosystems. Ants’ natural predatory instincts keep mosquito populations low enough that they don’t require chemical pesticides to manage them.
When ants forage on plant-sucking insects, such as aphids, they collect and store the sugary waste products known as honeydew. Ants then share that honeydew with their compatriots, keeping aphid populations in check and reducing the need for human pesticides.
In the same way, ants also prey on wood-munching termites. Their natural predatory behavior keeps termite numbers in check, preventing them from damaging houses and other structures.
By analyzing ants and ant communities, conservation scientists can get a glimpse into how an ecosystem is functioning. That’s why ants are the “go-to” insect to use as a bioindicator of biodiversity. They are also a good indicator of ecological restoration success. For example, when ants colonize a rehabilitated habitat, it’s usually a sign that the site has been successfully reintroduced to the wider landscape.
7. They Help to Control Wasps
For such small insects, ants make a big impact on the health of our ecosystem. They help to decompose organic waste, pollinate plants, disperse seeds, control pests and more. And while they may be a nuisance at times, these little workers should be treated with respect and appreciation.
Ants are a crucial part of many interspecific mutualisms, particularly as they travel long distances to and from gardens in search for food. A loss of these interactions would have profound ramifications on plant communities and on ecosystem function.
One example of this is a mutualism between ants and flowering plants called myrmecochory. When ants forage for nectar, they transfer pollen from one flower to another, promoting plant reproduction. This obligate mutualism is more likely to be disrupted by climate change than non-obligate mutualisms, and this could have significant consequences for plant diversity.
In addition, ants have been found to aerate the soil by tunneling through it, allowing more oxygen to reach plant roots. This also makes them a good choice for helping to restore degraded ecosystems such as wetlands, since they help to break down and recycle dead vegetation.