Desert ants have a unique way of using Earth's magnetic field for navigation

Desert ants, particularly the species Cataglyphis nodus, have amazed scientists with their navigational skills using magnetic field.

Researchers, led by Dr. Pauline Fleischmann from the University of Oldenburg, Germany, have unveiled a fascinating discovery about these ants.

Unlike other insects, they rely on a unique component of Earth’s magnetic field for orientation. This finding suggests that desert ants possess a distinct mechanism for magnetoreception that potentially involves tiny particles of magnetite or other magnetic minerals.

Magnetoreception in animals

Magnetoreception – the ability to detect the Earth’s magnetic field – remains a topic of intense scientific debate.

One theory centers on the radical-pair mechanism, a light-dependent quantum effect that allows an organism to detect subtle changes in the direction of the magnetic field.

Evidence from the Collaborative Research Centre’s Magnetoreception and Navigation in Vertebrates project supports the radical-pair mechanism in small songbirds and possibly insects, such as monarch butterflies.

Another theory involves tiny magnetic particles, within sensory or nerve cells, that act like compass needles.

Animals such as pigeons, bats, and sea turtles are thought to use this particle-based system. Both mechanisms appear to coexist in nature, demonstrating the complexity of magnetoreception across species.

Desert ants have magnetic sensitivity

To identify which mechanism desert ants use, scientists from the University of Oldenburg conducted behavioral experiments.

They hypothesized that animals using a particle-based system would respond to the north-south polarity of the geomagnetic field, while those using the radical-pair mechanism detect the field’s inclination.

Dr. Fleischmann, along with Dr. Robin Grob, Johanna Wegmann, and Dr. Wolfgang Rössler, explored the magnetic sense displayed by desert ants.

The experts focused on whether the ants detect the geomagnetic field’s inclination or polarity. This research builds on Fleischmann’s 2018 doctoral discovery that desert ants have a magnetic sensitivity.

Manipulating magnetic fields

The team conducted experiments on a Greek ant colony, using Helmholtz coils to create artificial magnetic fields.

Ants emerging from a nest were guided through a tunnel to an experimental platform, where their “learning walks” were filmed. These walks are crucial as ants memorize the nest entrance direction, using the magnetic field to enhance their visual memory.

“We suspect the ants use the magnetic field to train their visual memory,” Fleischmann explained. A recent study in PNAS on ant brain development supports this hypothesis.

Desert ants rely on polarity

In their experiments, the researchers altered the magnetic field’s inclination without affecting the behavior of the ants.

The ants continued to look towards their nest entrance. However, when the field’s polarity was reversed by 180 degrees, the ants misjudged the nest’s location entirely. This indicates that desert ants rely on polarity, not inclination, for navigation.

“This type of compass is particularly useful for navigation over comparatively short distances,” said Fleischmann. Monarch butterflies and songbirds, by contrast, use magnetic inclination as a navigational aid on their long-distance migrations.

Navigational skills of desert ants

Desert ants thrive in harsh environments like the North African Sahara’s salt pans or Greek pine forests, where landmarks are scarce.

Despite traveling hundreds of meters in search of food, they return to their nest entrance with remarkable precision. Their zig-zag outbound patterns transform into straight-line paths on their return.

This discovery sheds light on the evolutionary diversity of magnetoreception. Ants, bees, and wasps, all members of the Hymenoptera order, exhibit unique sensory adaptations.

“The fact that desert ants use a different mechanism for magnetoreception than other insects opens up new avenues for studying the evolution of sensory perception in the animal kingdom,” noted Fleischmann.

Implications for future research

Understanding the magnetic sense of desert ants not only deepens our knowledge of insect navigation but also highlights the intricate evolution of sensory systems.

This research paves the way for further investigation into how diverse species adapt to their environments using the Earth’s magnetic field as a guide.

More on desert ants

Desert ants are not just remarkable for their magnetic sense; they are also masters of adaptation. They thrive in some of the world’s most extreme environments, enduring temperatures that can exceed 50°C (122°F).

These ants have specialized heat-shock proteins that allow them to survive such intense heat. Additionally, their silvery body hairs reflect sunlight, which helps them maintain lower body temperatures.

Another fascinating aspect of desert ants is their reliance on path integration for navigation. They use a combination of step counting and celestial cues, such as the position of the sun, to calculate their precise location.

This allows them to find their way back to their nest even when their outward journey involves complex, winding routes.

Desert ants also exhibit impressive teamwork. They collaborate to transport large food items back to the nest and adapt their strategies based on environmental challenges. These survival traits make them an excellent model for studying behavioral ecology and evolutionary biology.

The study is published in the journal Current Biology.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—-