|
|
The monarch butterflies that hibernate in Mexico every year after traveling thousands of kilometers from the United States and Canada are arriving this week in Michoacán late and with a notable reduction compared to past seasons. "We more or less estimate that we have about 50% less until now (…). The figures are not very flattering," said the director of the reserve, biologist Gloria Tavera Alonso to the EFE agency. The monarch (Danaus plexippus) is a lepidopteran that continues to surprise scientists due to the mystery surrounding its migration. On Friday, the Sanctuaries of the Monarch Butterfly Biosphere Reserve opened, but the outlook is worrying because few specimens are arriving and about ten days late. If last season there was a 59% reduction in occupied areas for hibernating colonies in Mexico, the lowest level in 20 years, in the current season the situation is worse. Tavera gives as an example that if monarch butterflies were traditionally seen roaming around the cemeteries for the Day of the Dead, "this year, for the first time, none were seen.
In Mexico there has been a more intense and prolonged rainy season than usual, which prevents the flight of these butterflies and disorients their trajectory, a reason that may explain the delay in forming colonies in this country. Coupled with this, the population of these insects has been reducing because every day there are fewer areas of milkweed, a plant that the monarch butterfly chooses to lay its eggs. These insects use ravines to avoid strong winds as they head south, guided by the Sun, which is why they have come to be called the bride of the sun. This year, however, the weather Europe Cell Phone Number List has not favored migration. The specimens that hibernate in the sanctuary are great-great-grandchildren of those that were born in Mexico in the previous season. Those who reach Mexico form a generation so long-lived (they can live up to eight months) that they are called the Methuselah generation. In the United States and Canada they have a lifespan of several weeks, but those that travel south at this time live longer. Surveillance of this species is shared by the United States, Canada and Mexico. The latter country is responsible for protecting it during the five months of hibernation, although reproduction takes place further north. Tavera says there have been many studies to find out how the monarch butterfly orients itself, "but there are still many questions." "There's really no single answer yet." The influence of visitors The monarch butterfly reserve attracts about 200,000 visitors every year, who can see its colonies in Michoacán and, with a smaller area, in the State of Mexico.
Mexican officials also have their own problems protecting this insect from the flow of visitors, who can only observe the colonies in groups and accompanied by local guides. Not only is the butterflies' hibernation disturbed by noise, but on many occasions visitors take dead specimens, even though their remains are used as a guide to begin the return to the north. The nature reserve is still waiting for more specimens to arrive, although the largest number usually arrive in Mexico in the first half of November, which has already passed. In January, it is expected to have more details about the size of the occupied areas, based on the field work carried out during December, although the signs seen so far are discouraging. "There aren't that many trees occupied at this point. You have to give them time to continue establishing themselves," Tavera said. "Although they are delayed, we have not yet seen that wonderful event that was seen in other years; it has not been seen yet and we do not consider it to happen." In addition to the fact that many fewer copies have arrived than last year, and that they are arriving late, there are other concerns. "The only thing we are missing this season is a frost. We are praying that this does not happen," concluded the biologist.
|
|
發表於 2024-3-9 18:50:03
