From Crops to Sloths: The Sweeping Impact of Crazy Ants

Costa Rica has a problem, a crazy ant problem! A species of ant known as the ‘Rasberry Crazy Ant’ or Nylanderia fulva has become a huge issue in Costa Rica. Originally from South America, mainly Brazil and Argentina, these ants earn their name by their erratic, non-linear movement patterns. These crazy ants also pose a significant threat to the landscape, wildlife, and crops.

Crazy ants, an invasive species

These ants are known for their ability to create super colonies containing multiple queens, which grant them a strong reproductive capability, enabling crazy ant populations to attain population densities significantly surpassing those of other ant species.

*By Bentleypkt – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=37887707*

Invasive species, like the crazy ant, are non-native organisms that, once introduced, rapidly expand their territories beyond their initial points of entry. This expansion poses threats to the environment, wildlife, economy, and human health.

In Costa Rica, these ants were inadvertently introduced through agricultural activities. Dispatched materials from producers and marketers of vegetative and propagative materials from heavily infested areas have inadvertently transferred this pest to new regions. Crazy ants thrive in disturbed and artificial habitats, making them highly adaptable and resilient.

How Crazy ants affect ecosystems and crops

Crazy ants disrupt both the ecosystem and crops in several ways. They outcompete and displace native ant species due to their high adaptability and the ability to form super colonies with multiple queens, enabling them to rapidly increase their population and dominate local ant communities. This disruption upsets the balance of native species within the ecosystem.

Crops like sugarcane, coffee, ornamental plants, and other vegetative and propagative materials, are particularly vulnerable. Although this species doesn’t directly attack plants, they can transport harmful organisms such as aphids, mites, mealybugs, and scales that can cause substantial damage to crops.

Crazy ants versus the local wildlife

But it’s not just ecosystems and crops that suffer; local wildlife is also greatly affected. With their omnivorous and opportunistic feeding habits, crazy ants consume a wide variety of foods, including insects, small vertebrates, and plant matter.

The plague attacks other insects like the stingless Melipona bees. Authorities explain that where there is a presence of crazy ants, no type of arthropod (invertebrate animals such as insects, arachnids, and crustaceans) survives. *Photo: ACAT*

Their appetite also extends to larger animals like iguanas, coaties, sloths, birds, armadillos, and cattle. These ants have developed a particularly gruesome way of attacking their prey, using formic acid spray to incapacitate and exploit lesions, eventually devouring the animals alive.

The crazy ant feeds on the soft tissues and secretions of mammals like coatis. They can attack the eyes and cause temporary or permanent blindness. Photo: Screenshot from a video by the director of the Taboga Reserve, Juan Astorga.

Are sloths affected by crazy ants?

Sloths, in particular, are vulnerable to crazy ant infestations. These ants infiltrate sloth fur, including the head and neck areas, delivering painful bites that cause irritation, discomfort, and stress.

In response, sloths may increase their scratching and grooming behaviors to remove the ants. However, severe infestations can lead to open wounds and infections, posing a serious health risk to sloths, especially when the ants interfere with the sloth’s ability to move, feed, or defend itself.

Controversial Solutions

In response to this crisis, the Costa Rican government is taking action. They have temporarily authorized the use of agrochemicals such as fipronil, banned in the European Union, to combat crazy ants. Minister of Agriculture Victor Julio Carvajal has announced this authorization, particularly targeting crazy ant nests in sugarcane fields. Sugarcane, covering approximately 200,000 acres, plays a vital role in Costa Rica’s economy.

However, this reliance on agrochemicals has made pest management a controversial issue. While these measures aim to protect vital industries, environmental advocates have voiced concerns about potential impacts on soil, waterways, and other species, such as native bees. The government is also implementing strict controls on dispatched agricultural material to prevent the accidental transfer of ants from infested areas to new regions.

Why we should care about invasive species

The case of the ‘Longhorn Crazy Ant’ invasion in Costa Rica highlights the critical importance of controlling invasive species. These ants, originally from South America, have wreaked havoc on the landscape, wildlife, and vital crops.

The government’s temporary authorization of agrochemicals reflects the urgency of addressing invasive species to safeguard economic interests, but it also raises concerns about potential environmental repercussions. This situation draws attention to the need for proactive measures to prevent the introduction and spread of invasive species, emphasizing the importance of balanced pest management strategies that consider both ecological and economic aspects.

-Darlene Buibas

SloCo Collaborator

References

Alert: “Crazy ant” could spread in Costa Rica says Ministry of Agriculture. (2022, October 14). Q COSTA RICA. https://qcostarica.com/alert-crazy-ant-could-spread-in-costa-rica-says-ministry-of-agriculture/

Fernandez, I. (2023, August 24). Costa Rica Permits Agrochemicals to Combat Destructive Crazy Ants. The Tico Times | Costa Rica News | Travel | Real Estate. https://ticotimes.net/2023/08/24/costa-rica-permits-agrochemicals-to-combat-destructive-crazy-ants