Tired from a long journey, faded monarchs seek homes for the next generation

My friends Bob and Bev photographed this very faded, tattered female monarch flying around the milkweed plants in their backyard near the Museum last week. The butterfly is a migrant from Mexico, looking for places to lay her eggs as a last hurrah before she dies.

Detail of a healthy monarch’s wing

The monarch we found with faded, damaged wings

The monarch we found with faded, damaged wings

She must be very tired!

Last fall, she flew from somewhere in eastern North America all the way to central Mexico, where she spent the winter mostly in hibernation. A few weeks ago, she and the other overwintering butterflies, sensing the lengthening days and warming temperatures, left the shelter of the sanctuary’s trees and headed back north to complete the journey. They are just now getting to Texas.

This old girl’s eggs will hatch and — if they have enough milkweed — the caterpillars will mature and pupate. Then, when they emerge as adult butterflies, at least some of them will continue the journey north. By July, monarchs will have reached the northern limit of their range. These summer generations don’t live as long, and don’t travel nearly as far.

P1070759If you see worn and faded monarchs at this time of year, they are almost certainly migrants returning from their winter in Mexico. You can help them to fulfill their “purpose” by providing nectar for their last few meals, and more importantly, milkweed for the new generation. These returning migrants will only last a few days now that they’ve gotten here — they are on their last “wings” after nearly nine months of life, and at least 2,000 miles of travel.

P1070760

A healthy Monarch Butterfly

Monarchs want YOU to plant milkweed: Butterfly-friendly plants for sale at HMNS

The butterflies need your help! With urbanization, and a host of other factors, monarch butterflies are at risk of not finding places to lay their eggs. So why not help while improving the butterfly traffic through your garden with a butterfly-seducing plant from our biannual plant sale?

Milkweed plants in the genus Asclepias are extremely important for butterflies, especially monarchs. While the blooms provide copious amounts of nectar for many different butterflies, the foliage is an essential part of the monarch butterfly’s life cycle. Milkweeds are the only plant monarch caterpillars will eat. In other words, they can’t live without it!

Native milkweed plants grow along roadsides and in open fields. The butterflies find them by honing in on their volatile chemicals and finally locate the exact plant by “tasting” nearby plants with special receptors called chemoreceptors on their feet. Once a gravid female (one who has mated and is ready to lay eggs) finds a good milkweed plant, she will lay eggs on it — and the miraculous process of metamorphosis has begun!

There are about 100 species of Asclepias in the United States, and over 30 in Texas — but monarchs seem to prefer some of them over others. According to a study by Linda S. Rayor, described in The Monarch Butterfly: Biology and Conservation, when given a choice, monarchs prefer to lay eggs on other species of milkweed over the native species Asclepias tuberosa.

Butterfly - Tropical Milkweed

Besides being a host plant for Monarch larvae, Tropical Milkweed (A. curassavica) is a great nectar source for many butterfly species!

Why? Different Asclepias species contain different cardenolide concentrations (cardenolides are the chemicals in the milkweed leaves that taste bitter). As they eat, the caterpillars store these toxic chemicals in their bodies and thus become distasteful to their predators. A. tuberosa has been found to contain low amounts of cardenolides compared to most other species of milkweed. Although it is unclear how monarchs “know” this, they do not usually use A. tuberosa as a host plant.

Several other native milkweed species, however, are great host plants for the monarch. Asclepias asperula (Antelope Horns), A. viridis (Green Milkweed), A. incarnata (Swamp Milkweed) and A. oenotheroides (Zizotes Milkweed) are some of the more commonly found milkweed plants in our area that monarchs use as host plants.

Unfortunately, most of the native milkweeds are hard to find in plant nurseries. One reason is that their seeds require moist stratification to germinate, and even with this pretreatment, germination can be splotchy. Furthermore, young plants of A. asperula, viridis and oenotheroides take several seasons to establish their thick taproots, and can be hard to transplant.

On the bright side, most of the native milkweeds, except for A. incarnata, are drought tolerant and can handle being mowed. Swamp milkweed obviously likes moist soil. All milkweeds grow best in full sun.

Butterfly - Green Milkweed

Asclepias viridis, Green Milkweed

Most gardeners are familiar with tropical milkweed, or Asclepias curassavica. This plant is commonly available in local plant nurseries and attracts butterflies like a magnet! Its bright orange and gold flowers are irresistible to many butterflies, and the high levels of cardenolides in its foliage make it especially sought out by female monarchs looking for a place to lay their eggs. Although it originates in more tropical climes, it is relatively cold hardy and will usually come back from the base of the plant after a freeze. It is also easy to propagate from seed, and in fact will sometimes seed out (make more of itself) in a garden.

So tropical milkweed seems like the ideal plant. However, one issue with this species is that it is not native to our area and does not exhibit the same characteristics of our native milkweeds, all of which die back to the ground in winter. This perennial habit seems advantageous, but it can be a problem for a couple of reasons. Because it has leaves year-round, it may encourage monarchs to overwinter locally instead of migrating to Mexico. It can serve as a host for a disease that affects monarchs, called Ophryocystis elektroscirrha, or simply O.e. This disease is caused by a protozoan parasite and is spread in the dormant stage of its lifecycle as a tiny spore.

These spores are typically on the abdomen of an infected monarch butterfly and can be spread to her eggs or onto the milkweed plants themselves when a female lays eggs. Then, when the caterpillars hatch out of the eggs, they consume the spores that lie on their empty egg shells or on the leaves around the egg and become infected.

Over a few generations, the parasite load can build up to high enough levels that it impacts the butterfly’s survival. Depending on the severity of the infection, the disease can make the caterpillars look a bit grayish and their stripes not as distinct. When the caterpillars pupate, their chrysalis may look brownish or spotted. The butterfly inside may emerge but have problems, such as an enlarged, gray abdomen and weak, faded wings.

Sometimes they emerge and look healthy, but secretly harbor O.e. spores on their abdomens. Other times they don’t emerge from the chrysalis at all, or get stuck while trying to come out.

So what is my point? I thought we were talking about milkweed plants! ;-) The reason this is important is because O.e. spores persist on the leaves of the tropical milkweed plants, waiting for an unsuspecting caterpillar to munch them up. To break this cycle, we recommend cutting your tropical milkweed plants back after a monarch generation has stripped their leaves, especially in the spring and fall. A simple pruning of the plant’s stems about six inches from the ground will get rid of any remaining spores and will sprout new growth in no time.

Some other closely related plants that monarchs will use as a host are Gomphocarpus physocarpus or “family jewels” milkweed, and a species of Funastrum or twinevine. Gomphocarpus is a lot like A. curassavica in that it doesn’t lose its leaves in the winter so it also needs to be cut back periodically to keep it from spreading O.e.

Butterfly - Funastrum cynanchoidies flower

Funastrum cynanchoidies flower

Funastrum or twinevine is an interesting climbing plant native to south Texas and Mexico. The plant is not very impressive looking until the summer, when it puts on beautiful balls of milkweed-like flowers that are great nectar sources for many kinds of butterfly. Another good thing about it is that when monarch caterpillars have stripped all your milkweed plants of their leaves and are still hungry, they will eat the leaves of Funastrum.

With their habitat dwindling due to urbanization, the use of Round Up ready crops, shrinking right-of-ways due to intensive agricultural practices and other factors, monarch butterflies need all the help they can get. The take-home message today is PLANT MORE MILKWEED! (please)

For milkweed and other awesome butterfly host and nectar plants, come visit us at our biannual Spring Plant Sale on Saturday, April 5th from 9 a.m. until we sell out! We are located on the 7th level of the Museum parking garage. Parking is free if you spend $30 or more!

Come early, the plants go fast!

Plant Sale: This Saturday

Today’s post was written by Soni, horticulturalist for our Butterfly Center. She and the other employees are hard at word preparing for our upcoming Plant Sale on October 2.

I’m sure not very many of you are thinking of rolling up your sleeves and heading into the blazing heat of summer to do a little gardening. What you should do is start thinking ahead to fall, planning your garden for when the weather cools off and you can once again step outside of the air conditioning without having a heat stroke. If your garden needs a perk up after this summer, you should head over to the Cockrell Butterfly Center’s Fall Plant Sale which will be this Saturday, October 2, from 9 a.m. to 1 p.m., on the 7th level of the parking garage at the Houston Museum of Natural Science.

Bouquet of Coneflowers
Coneflowers
Creative Commons License photo credit: Randy Son Of Robert

Twice a year we have a sale where we carefully select just the right plants for you to put in your garden to attract butterflies and their offspring. How do you go about attracting butterflies and their offspring? Well, first of all, you need lots and lots of nectar plants, the more variety the better. The best nectar plants are those with small tubular flowers arranged in clusters, sometimes with brightly colored petals that serve as a target to alert the butterflies that, “Hey! There’s food over here!” Butterflies survive on a liquid diet because of their specialized mouthparts, collectively called a proboscis. It looks like a coiled straw which they unravel to poke down inside flowers and consume the sugary liquid. Some examples of excellent nectar plants are Coneflower (Echinacea sp.), Black and Brown Eyed Susan (Rudbeckia sp.), Native Gayflower (Liatris sp.), Lantana, Verbena, Porterweed (Stachytarpheta sp.), Salvia, Heliotrope, Mexican Sunflower (Tithonia) and many, many more.

Did you think I forgot to mention their offspring? Of course not, that is my favorite part of butterfly gardening! Let’s back up for a minute so you can see the big picture. A butterfly’s life is comprised of four stages. In each stage the creature looks totally different. The whole lifecycle is called complete metamorphosis (meta means change, and morph means form). The first stage is the egg, which was laid by its thoughtful mother on a very important plant called a host plant. (Did you know butterflies are really good botanists? The story gets even weirder. They can tell plants apart by tasting them with their feet!) When the egg hatches, a caterpillar (otherwise known as a larva) crawls out and immediately eats the egg shell. Then, the caterpillar looks around and wonders, “What else is there to eat around here?” Well, little friend, you are sitting right on top of it. The host plant is the food, the life support, for the caterpillar. Without host plants we would not have butterflies!

Monarch Butterfly (Danaus plexippus) monarch-butterfly_2
Monarch Butterfly
Creative Commons License photo credit: mikebaird

Each type of butterfly corresponds to a different type of host plant. For example, the well known Monarch butterfly only lays its eggs on the Milkweed plant (Asclepias sp.). The Monarch caterpillars will not eat Parsley or Dill, but you know who will? The Black Swallowtail, that’s who. Other host plants that attract our native butterflies are: citrus species, rue (Ruta graveolens), and wafer ash (Ptelea trifoliate) for the Giant Swallowtail; Dutchman’s pipevine (Aristolochia fimbriata and A. elegans) for Pipevine and Polydamas Swallowtails; spicebush (Lindera benzoin) and sassafras (Sassafras albidum) for the Spicebush Swallowtail; sennas (Cassia sp.) and partridge pea (Chamaecrista fasciculate) for Sulphurs; and passionvines (Passiflora sp.) for the Gulf Fritillary.

The third stage of metamorphosis is the chrysalis (or pupa), which is what the adult butterfly (the fourth and final stage) emerges out of.

When you combine nectar and host plants in your landscape you will not only increase your chances of seeing butterflies, but you can also have the experience of witnessing the amazing process of metamorphosis first hand. If you don’t want to see plants that are chewed up, you can omit the host plants, or place them behind other plants, however, watching a butterfly lay eggs and watching caterpillars grow is pretty cool.

We will have the majority of the plants mentioned above at the plant sale, plus many more (a “complete” list is on the website). The selections we have made are for growing in Houston and the surrounding areas, a lot being native plants. You can also learn about gardening for butterflies at the sale from our knowledgeable staff and volunteers. Hope to see you there!

Here are some tips for attending the plant sale:
1. Get there early. Don’t wait and expect to have a lot to choose from an hour before we close.
2. We will have wagons for customers to cart their plants to their cars, but if you have your own, bring it.
3. We take cash, check and credit cards.
4. The lines are long, but look at it as a time to make new friends or learn something new.   

Butterfly Gardener Alert!

Today’s post was written by Soni, horticulturalist for our Butterfly Center. She and the other employees are hard at word preparing for our upcoming Plant Sale on April 10.

She Was Completely Transparent With Me
Creative Commons License photo credit: Randy Son Of Robert

Got butterflies? Probably not, if your garden suffered freeze damage over the past few months. After this unusually long and cold winter, many of us have lost plants, especially species that are more tropical and not adapted to freezing temperatures.

But now that winter is finally behind us, it’s time to replant! Butterfly gardeners won’t want to miss the Cockrell Butterfly Center’s Spring Plant Sale. It’s happening soon:  Saturday, April 10, 2010 from 9 a.m. to 1 p.m., on the 7th level of the parking garage at the Houston Museum of Natural Science.

Some of you may be seasoned butterfly gardeners, but others may be asking, “How DO you ‘garden’ for butterflies?” It’s quite simple.   For a successful butterfly garden you need two types of plant:  nectar and host plants.

Mix of flowers

Coneflowers and Rudbeckias
Creative Commons License photo credit: Per Ola Wiberg ~ Powi

Thanks to their specialized mouthparts – a long, thin, straw-like proboscis – adult butterflies can only consume liquid food.  The blooms of nectar plants produce a sugary liquid (nectar) that butterflies sip to give them the energy to fly, mate, and produce eggs.  Most nectar plants have colorful flowers borne in showy clusters.  Some examples of good nectar plants for our area are Porter Weed, Echinacea (Purple Cone Flower), Zinnias, Rudbeckia (Brown and Black-eyed Susans), Monarda (Bee Balm), Lantana, Salvias, Eupatorium (Mistflower), Cuphea, Buddleia (Butterfly Bush), and Tithonia (Mexican Sunflower), among many others.

Green Papilio polyxenes caterpillar

Eastern Black
Swallowtail Caterpillar
Creative Commons License photo credit: cyanocorax

In contrast to the adults, baby butterflies, aka caterpillars, have chewing mouthparts and eat leaves.  Many butterflies are quite choosy in their caterpillar stage, and can only survive and grow on specific plants, which we call host plants.  For example, Monarch caterpillars will only eat Asclepias (Milkweed); they cannot and will not eat anything else.  Female butterflies seek out the appropriate host plants for their babies when they are laying eggs.  Some host plants that can be included in your butterfly garden are Asclepias (for Monarchs and Queen Butterflies); Passionvines (for Gulf Fritillaries and if you’re lucky, Zebra Longwings); Citrus and Rue (for Giant Swallowtails); Dill, Parsley, and Fennel (for Black Swallowtails); Aristolochia aka Pipevine (for Pipevine and Polydamas Swallowtails); and Cassia aka Senna (for Sulphur Butterflies).  If you see caterpillars eating these plants, rejoice!  You will soon have lots of beautiful butterflies coming to your nectar plants.

Some of you may think you don’t want caterpillars eating away in your garden.  If so, you can avoid host plants and include only nectar plants.  However, you’ll get more butterflies if you plant both.  We predict that soon you’ll be treasuring every caterpillar!

Many of the nectar and host plants listed above will be available at our sale.  We strive to provide butterfly-attracting plants that are either native or naturalized in Texas, and that perform well in the Houston area.  Our sale is also a good place to learn more about butterfly gardening.  Several experts will be on hand to answer questions and to help you choose plants.


Plant Sale! At the Cockrell Butterfly Center from HMNS on Vimeo.

So save the date:  Saturday, April 10, from 9 a.m. to 1 p.m.  Come early, the plants go fast!