How could YOU answer it? The monarch stores a poison called cardenolides, or cardiac glycosides that it gets from the plants it eats. This poison is similar to digitalis, which can be used to help people with heart problems, but can kill people if they consume too much of it.
These are poisonous to most vertebrates animals with backbones , but they may not be poisonous to invertebrates animals without backbones. The potency of monarchs depends on the potency of the plants they ate when they were caterpillars. Some kinds of milkweed have higher levels of cardiac glycosides than others.
The effect of the toxin depends on the amount of toxin that the predator eats, and what kind of animal the predator is. There are some birds that eat monarchs, some mammals mice , several insects, and some parasites.
Briefly, many insects stink bugs, wasps, ambush bugs are some eat monarchs. See the Monarch Watch homepage. We have a good section on this. The two bird species that eat monarchs in the Mexican overwintering colonies have probably evolved to be able to tolerate the toxins, and this is apparently true of the mice as well. Of five species of mice that are common around the overwintering sites in Mexico, only one eats monarchs, Peromyscus melanotis, the scansorial black-eared mouse.
In fact, one mouse can eat about 37 monarchs a night. In two different summers, mice have eaten monarch pupae that were in cages that I was keeping outside in Minnesota. We do know that some predators seem to be able to tolerate the toxins in monarchs with very few problems. Maybe individual birds do need to wait a while after eating monarchs.
The orioles that eat the monarchs actually avoid the toxins by not eating the cuticle skin where most of the toxins are stored. The grosbeaks do eat the cuticle, but they prefer males, who have fewer toxins. This varies a lot in different areas. Where I live, common milkweed, or Asclepias syriaca is most abundant. Other species are more abudnant in other areas. For a nice description of many kinds of milkweed, you could look at the Monarch Watch homepage. No, but there are a few species of parasitic wasps that lay eggs in monarch larvae and pupae.
These eggs turn into wasp larvae that eat the monarch, then pupate and turn into new wasps. Monarchs can be infected with a protozoan parasite called Ophryocystis elektroscirrha. This parasite is transmitted from mothers to offspring, or from males to females during mating. If these monarchs are infected, they will spread spores on all of your cages and other materials, and larvae that you raise could easily be contaminated.
Anywhere that there are milkweed and flowers for nectar. I find it easier to find the larvae than the adults; just look at lots of milkweed plants. Some do live in parts of the Rocky Mountains. However, at very high altitudes there is no milkweed. Most scientists think that they originated in the New World tropics North and South American and have spread to other places in the last few centuries.
This spread was probably enabled by humans, who planted milkweed in new areas, and then may have moved the butterflies on purpose or by accident. Yes, monarchs are found in many places throughout the world, but they probably originated in the Americas, and were spread either with the help of humans or on their own to other places.
They are found in Australia and New Zealand, and many islands east of these countries most islands between Australia and Tahiti have monarchs. They are also found in Hawaii, most islands in the Caribbean, and even sometimes in western Europe.
There are different subspecies of monarchs. Most of those found in South America are a different subspecies than the ones you see in North America. In islands in the Caribbean, both subspecies are sometimes found. Monarchs are found in many places throughout the world, but they probably originated in the Americas, and were spread either with the help of humans or on their own to other places.
They can survive short periods of freezing temperatures, but not long periods. The trees offer the monarchs protection from extreme temperatures, predators, and precipitation rain and snow. Many people, particularly Alfonso Alonso, Lincoln Brower, Eneida Montesinos, and Eduardo Rendon, are studying how important the trees in the overwintering sites are to the monarchs. Eneida once said to me that she loves the monarchs, but she loves the forest even more, because without the forest there could be no monarchs.
It is very clear that the trees are absolutely necessary to the survival of the monarchs. I answered the first question earlier. Any mortality affects their population somewhat, but animals that have such a high rate of reproduction can recover from short periods of high mortality. The key is short periods of high mortality - if this continued, it would affect their future survival. For example, if a hard winter is followed by a hard spring and summer, that would be very bad.
So far, this spring is not looking very good for monarchs - it has been cold and dry in the Southern US , and there are not a lot of flowers or milkweed plants available. This could cause problems, but an excellent summer in the Northern US could allow the monarch population to bounce back. Eastern Tiger Swallowtails are unusual because the species benefits from two different kinds of mimicry. All male Eastern Tigers and some females resemble Monarchs enough to discourage some birds.
Other females resemble a smaller Swallowtail, the Pipevine Swallowtail, which absorbs different toxins from a different food plant. Individual Tigers who resemble Pipevine Swallowtails are much more numerous in places where real Pipevine Swallowtails live. Viceroy Butterfly caterpillars eat willow, poplar, and cottonwood tree leaves.
They absorb salicylates, chemicals similar to the active ingredient in aspirin. This gives them a bitter taste and makes them poisonous to some predators. Adult Viceroys are composters, and may pick up additional toxins and disease germs from the decaying material from which they drink liquid residues. One of the perils of Monarch Butterfly migration is that Monarchs lose some of their toxicity during hibernation.
By early February, mice who invade Monarch Butterfly Sanctuaries may be able to eat one butterfly and still feel interested in eating another one. Fortunately for the butterflies, the weather will soon be warm enough for them to fly away. Monarchs who have hibernated benefit from their resemblance to Monarchs who have not. Birds might be able to eat these individuals, but the birds do not know this. No matter how hungry we are, few humans have ever wanted to eat butterflies.
For us the benefits of close observation of butterflies are different. More accurate butterfly drawings make it easier to share information about butterflies. Accurate information about butterflies helps us recognize their value as pollinators. Scientists classify butterfly species in families based on their shapes. When you compare species, you notice that Monarch Butterfly outlines and wing venation patterns are different from their look-alikes. In swallowtail species that have striped wings, wide black or brown stripes often cross out the pattern the veins form in each wing.
Anglewing butterflies get their name from the angular outlines of their wings. Compare the left photo of the Monarch to the right photo of its mimic. This mimic, called a Viceroy Limenitis archippus , does not feed on milkweed and is not toxic. It would be acceptable food for a bird, but if the bird has already learned not to eat a Monarch, the bird will leave the Viceroy alone as well.
If a bird ate a Viceroy first, it might not learn that the color pattern is meant to be a warning. That would make the mimicry less effective, so there are fewer Viceroys than Monarchs. Lower numbers of Viceroys increase the chances that the first contact a bird has would be with a Monarch. As fall approaches, some individual Monarchs begin a migration.
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