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Thursday, September 24, 2009

Monarchs use antenna sensors to find Mexico

"Millions of Monarch butterflies migrate to Mexico for the winter and scientists have long speculated on how the insects find their way. Turns out, their antennas are the key.

How do we know? Well, researchers painted butterfly antennas black, and the insects got lost.

Managing to fly south may not sound like a big deal to people armed with maps and GPS receivers, but all butterflies have for navigation is the sun in the sky.

And the sun keeps moving, so the little creatures have to constantly adjust to stay on course throughout the day.

Like most animals, Monarchs have a so-called circadian clock in their brain that helps them know what time it is. Knowing the time and the position of the sun allows them to orient to the south.

But Monarch butterflies have a second clock based in their antennas, which also sense light, according to the new study led by Dr. Steven M. Reppert, chairman of neurobiology at the University of Massachusetts Medical School."

Source of article:

According to Dr. Reppert:

"During their fall migration, monarch butterflies travel distances approaching 4000 km. The remarkable navigational abilities of monarch butterflies are part of a genetic program that is initiated in migrations. We believe that the centerpiece of the navigational process is time-compensated sun compass orientation. The ability of migrants to successfully navigate to their overwintering sites in central Mexico requires that the underlying genetically program is constantly being recalibrated by environmental factors."

"Based on studies in locusts and crickets, it appears that the sun compass resides in the central complex. The central complex is a midline structure consisting of the dorsally positioned protocerebral bridge and the more ventrally situated central body, which has upper and lower subdivisions. Our recent finding of a clock connection with the central complex (via a CRY2-positive pathway) in monarch butterflies represents a major advance"
(See this diagram::

"Migratory monarch butterflies are gregarious, while summer butterflies are not. Migrants spend their nights in roosts along the migration flyway. They migrate in large swarms, which increase in size the closer they get to Mexico. Do social interactions among butterflies influence their navigation. Flight simulator experiments could help determine whether social interactions actually influence time-compensated sun compass orientation mechanisms. We are also investigating whether pheromones are important."


To see some short videos about the monarch butterfly migration to Mexico click on these links:

Here are some facts about Monarch Butterflies:

The monarch butterfly is sometimes called the "milkweed butterfly" because its larvae eat the plant. In fact, milkweed is the only thing the larvae can eat! Adult female monarchs lay their eggs on the underside of milkweed leaves. These eggs hatch, depending on temperature, in three to twelve days. Most predators have learned that the monarch butterfly makes a poisonous snack. The toxins from the monarch's milkweed diet have given the butterfly this defense. In either the caterpillar or butterfly stage the monarch needs no camouflage because it takes in toxins from the milkweed and is poisonous to predators. Many animals advertise their poisonous nature with bright colors... just like the monarch! (source:

  • "The monarch butterfly migrates over 3,100 kilometers, without ever having been to its destination.
  • The male monarch butterfly is distinguishable from females by the black-colored scent glands on each hind wing.

  • The monarch butterfly caterpillar sheds its skin four times within two weeks of hatching.
  • When the monarch butterfly caterpillar is two weeks old, it weighs 3,000 times as much as it did when it was born.
  • After the monarch butterfly emerges from the pupa, it must pump fluid into its wings and wait for them to harden before it can fly.

  • After laying about 400 eggs, the mother monarch abandons her young to look after themselves.
  • Monarch butterflies that breed early in the summer die within a few weeks. If a monarch butterfly does not breed before late August, however, its reproductive maturity will be postponed and it will live for up to nine months. It is these "late bloomers" that migrate from Canada to Mexico. (source:"

"The life span of the adult Monarch varies, depending on the season in which it emerged from the pupa and whether or not it belongs to a migratory group of Monarchs. Adults that emerged in early summer have the shortest life spans and live for about two to five weeks. Those that emerged in late summer survive over the winter months. The migratory Monarchs, which emerge from the pupa in late summer and then migrate south, live a much longer life, about 8-9 months. "
Order: Lepidoptera (butterflies and moths)
Family: Nymphalidae (over 5,000 species of butterflies with dwarfed front legs)
Subfamily: Danaidae (milkweed butterflies)
Genus and species: Danaus plexippus


Source of image:

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Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed

Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia

A person's true wealth is the good he or she does in the world. - Mohammed

Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein

The best way to find yourself, is to lose yourself in the service of others. - Ghandi

The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller

Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns

Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama

Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -

Milan Kundera, The Unbearable Lightness of Being

The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.