Monarch Butterflies: Tiny Tag, Big Discovery
Scientists have made a significant advancement in tracking monarch butterflies, now able to follow individual butterflies on their long migrations from places like Ontario to Mexico. This breakthrough is made possible by tiny, solar-powered radio tags weighing just 60 milligrams. These tags are attached to butterflies, which typically weigh between 500 and 600 milligrams. The tags are so light that it's akin to a half-raisin carrying three grains of rice.
Innovative Tracking Technology
The tags are developed by Cellular Tracking Technologies. Over 400 monarchs have been tagged this year. Researchers can monitor the butterflies' journeys using a special app called Project Monarch Science, which is free for anyone to use. The app provides real-time data on the butterflies' locations and movements.
Advancements Over Traditional Methods
The new tags represent a major improvement over the old method of tracking monarchs with small stickers. These stickers only indicated where the butterfly was tagged and where it was found. In contrast, the new tags provide a complete journey, offering insights akin to reading an entire book rather than just the first and last pages.
Monarchs' Remarkable Navigational Skills
The tags have already revealed that monarchs possess extraordinary navigational abilities. They use the sun to guide them during the day and switch to a backup compass that detects the Earth's magnetic field using ultraviolet light when it's cloudy. This helps them stay on course even in adverse weather conditions.
Survival Challenges
However, not all monarchs complete their journey. Only about one in four survives the migration. The rest perish due to bad weather, predation, or exhaustion. Those that do survive join massive flocks in Mexico, sometimes so large that they bend the branches of the trees they roost on.
Declining Monarch Populations
Monarch numbers have been declining. In the 1990s, there were hundreds of millions of monarchs in Mexico. Now, there are usually fewer than 60 million. Last winter, there were only about 38 million. The West Coast population is even smaller, with fewer than 10,000 monarchs last winter.
Causes of Decline
The decline is attributed to several factors:
- Climate change making it harder for them to find food.
- Deforestation and beetle infestations threatening their winter homes.
- Herbicide use on farms destroying their breeding grounds.
Company Behind the Technology
Cellular Tracking Technologies, based in New Jersey, manufactures tags for various animals, from bumblebees to elephant seals. The company's founder, Michael Lanzone, has been working on this technology for 20 years, aiming to enhance scientific understanding of these insects.
Initial Testing and Success
The tags were first tested in Ontario, Canada, where researchers tagged 30 monarchs. One monarch, a female named LPM021, flew far beyond known colonies and was last seen 425 miles from Guatemala.
Expanding the Research
Following the success in Ontario, the company provided more tags to researchers. The app soon filled with butterfly tracks, sparking excitement and a friendly competition to see which monarch would reach Mexico first.
The Winner of the Migration Race
A monarch named JMU004, tagged in Virginia, won the race to Mexico in 47 days. The scientist who tagged him, Leone Brown, shared the triumph with her 7-year-old daughter. However, the scientists emphasize that the true goal is to learn more about these incredible insects and their survival strategies.
