It Takes a Village ….A Milkweed Village

monarch-2

As the obligate host plants for monarch caterpillars, milkweeds are a staple in any butterfly habitat garden. However, milkweed is not just for monarchs! Many other insects call the genus Asclepias home, giving rise to the concept of a “milkweed village.”

Milkweed plants produce bitter tasting toxins called cardiac glycocides, and insects that eat milkweeds have evolved to use these to their advantage, sequestering the toxins in their bodies to protect themselves from predators. Most, if not all milkweed-eating insects have markings of black and orange or yellow, a type of aposomatic coloration that warns predators of their horrible flavor. If a predator such as a bird, lizard, or spider were to eat one of these insects, it would spit it out. The next such insect would be avoided, as its coloration would remind the predator of its foul flavor.

Most butterfly gardeners have encountered the bright yellow oleander aphid, Aphis nerii, which congregates on the new growth, flowers, and developing seed pods of milkweed plants. Aphids are phloem feeders, meaning that they suck the sap, along with the toxins, out of the plant’s vascular tissue.

Ladybug larva

Ladybug larva

The presence of these aphids on milkweed attracts a number of predatory insects. Ladybug larvae and adults (Hippodamia spp. and others) are important predators of milkweed aphids. Other small beetles such as mealybug destroyers, Cryptolaemus montrouzieri, and scale destroyers, Lindorus lopanthae, eat aphids along with other small sap-feeding insects. These beetles are interesting creatures in that their larval stage looks just like their namesake (i.e., mealybugs and scale, respectively).

scale destroyer larva2

Scale destroyer larvae

The maggot-like larvae of syrphid flies also eat aphids, sucking their bodies dry. Syrphid pupae look like little brown or tan teardrops. If you notice these on your milkweed plants, leave them in place to ensure another generation of these beneficial flies.

Syphid fly pupa

Syrphid fly larva

Tiny parasitic wasps such as braconids lay their eggs in aphids’ bodies. The wasp larvae feed on the inside of the aphid until they pupate, then exit as an adult wasp through a tiny hole in the aphid’s exoskeleton. The leftover brown “shell” is called an aphid mummy. These mummies are a good sign that your aphids are being parasitized. Don’t worry, these wasps don’t harm monarch caterpillars.

aphid mummy

Aphid mummies

With all of these great beneficial insects around, I hardly had to spray our milkweed crop at the museum with any insecticidal soap this year. However, if the aphid population on your milkweeds gets to be overwhelming, the best way to knock them back is to spray them off the plants with a sharp stream of water. Try to avoid damaging or knocking off any beneficial insects in the process.

Other “pests” of milkweed plants include the milkweed leaf beetle, Labidomera clivicollis. These chunky, orange and black beetles and their larvae feed on milkweed leaves.

Milkweed Beetle (Wikipedia)

Milkweed Beetle (Wikipedia)

Large milkweed bugs, Oncopeltus fasciatus, are also common in the southern United States. These oblong-shaped, sap-sucking true bugs are orange and black and mostly feed on the developing seeds, flowers and nectar of milkweed plants. They don’t usually cause much damage.

Now we come to the most familiar milkweed inhabitant – the monarch butterfly, Danaus plexippus. As we all know, monarch caterpillars eat voluminous quantities of milkweed leaves, and display the textbook aposomatic coloration of white, black and yellow stripes. Their chrysalids, or pupae, are a gorgeous jade green with gold lines and spots.

monarch

Here in Houston we sometimes encounter another milkweed visitor – the queen butterfly, Danaus gilippus. Queen caterpillars look very similar to the monarch, but they have three pairs of tentacles instead of the monarch’s two. Their chrysalids are also similar, but are a bit smaller and may sometimes be a pale pink rather than green.

Like everything else, monarchs are part of the food chain, and are preyed upon or parasitized by a number of different organisms. One of their most prevalent parasites is a tachinid fly, a gray, hairy species about the size of a house fly. An adult fly female will lay her eggs on a monarch caterpillar and when they hatch, the maggots burrow inside. The maggots live inside the caterpillar, eating its tissues, until they are ready to pupate. At that point they crawl out of the caterpillar and fall to the ground, where they pupate in the soil The maggots often leave the caterpillar after it has pupated, leaving a trail of slime that dries up and looks like white strings hanging from the chrysalis. These strings are tell-tale signs of a tachinid fly infestation.

Tachinid fly larva emerging from monarch caterpillar.

Tachinid fly larva emerging from monarch caterpillar.

Assassin bugs, Zelus sp., are frequent visitors to milkweed plants. This true bug will stab monarch caterpillars with its rostrum or beak, paralyzing the victim and liquefying its insides, making it easier to consume.

Vespid wasps are another important predator of monarchs. The familiar large red wasps, Polistes carolinus, and the smaller yellow and black European paper wasp, Polistes dominulus, both hunt caterpillars as food for their own hungry larvae. Once a wasp finds a host plant with caterpillars, she will come back regularly to check for more, especially in the summer months when wasps are the most active. This can be upsetting to butterfly gardeners. To protect your caterpillars from these all-too-efficient predators, place a screen such as a pop up or mesh laundry hamper between them and the wasps.

Polistes carolina  Photo by Val Bugh

Polistes carolina Photo by Val Bugh

 

Polistes dominulus

Polistes dominulus

Finally, a parasite of notable concern that specifically affects monarchs (and also queens) has emerged on the scene of butterfly gardening. This protozoan parasite, Ophryocystis elektroscirrha, commonly known as Oe, begins with a dormant spore, usually deposited by an infected female monarch as she lays her eggs on a milkweed. When the caterpillars hatch and begin to eat, they consume the Oe spores along with the leaf. Once inside a caterpillar’s gut, the spores become active and reproduce several times. When the butterfly emerges from its pupa, it is covered in dormant Oe. spores, giving rise to the next generation of infected monarchs. Mildly infected butterflies may show no sign of infection but as Oe levels build up, they eventually cause problems such as weakness, deformity, and even death.

OE Life Cycle (Monarchparasites.org)

OE Life Cycle (Monarchparasites.org)

The annual migration to Mexico each fall helps to weed out infected butterflies, which are usually too weak to make the long trip and die along the way. However, some monarchs don’t migrate and may stay in the Houston area all winter long. In the south, butterfly gardeners primarily grow tropical milkweed, Asclepias curassavica, which unlike the native milkweeds does not die back to the root in the fall. Oe spores can remain viable on the leaves of this perennial species for some time, infecting the next generation of caterpillars that eats them. As this situation repeats, it can cause populations of severely infested monarchs. We therefore encourage butterfly gardeners to cut back their tropical milkweed every spring after the first generation of monarchs arrive and eat the milkweed down, and then again in the fall before or during the migration, so that the butterflies will be encouraged to migrate and not overwinter here.

Spiny soldier bug nymph eating a monarch caterpillar. (Photo by Dan McBride)

Spiny soldier bug nymph eating a monarch caterpillar. (Photo by Dan McBride)

With all of these challenges, it’s no wonder that only five to ten percent of monarch eggs make it to adulthood. Keep in mind however, that monarchs are an important part of the food chain and without their survival and natural demise, our native ecosystem would not be as diverse as it is. In any case, human interactions with the environment have caused the most damage to monarch populations – huge amounts of monarch habitat has been lost due to the expansion of agricultural land and use of Roundup Ready crops. Planting butterfly-friendly gardens, especially if they include milkweed, can help mitigate this loss of habitat.

You can do your part by attending our fall plant sale at the Houston Museum of Natural Science. Stock up on the nectar plants that monarchs need to fuel their migration as well as host plants for native butterflies.

The sale will be held on Saturday, October 11th from 9:00 a.m. until noon (or until plants are gone), and will take place on the 7th level of the museum parking garage. Remember, the early bird gets the larva, so to speak, and don’t forget your wagon!

Four Ways to give your kid a great birthday at HMNS

Planning a great birthday party for your little tyke can be daunting to say the least, that’s why we’re here — to make sure your kid AND their friends AND you can have a great time at their birthday party!

To top it off we’re running a special of $50 off all remaining 2014 parties* at both of our locations** (including Deluxe Packages!) booked between September 1st-15th, 2014! Don’t miss out!

“What’s a Deluxe Package?” you ask, why it’s only the best way to celebrate in the museum. Here are the four Deluxe Package options:

1. PARTYSAURUS

Party among prehistoric beasts in HMNS’ expansive new Hall of Paleontology and enjoy a spectacular view from above. Click here for more information.

Success Kid Meme - Dinosaur Birthday Party

2. WINGED WONDERLAND

The Cockrell Butterfly Center provides a stunning backdrop for the ultimate butterfly or insect fan! Click here for more information.

Success Kid Meme - Butterfly Birthday Party

3. GALACTIC GATHERING

You and your guests will enjoy an out of this world party in the Arnold Space HallClick here for more information.

Success Kid Meme- Space Birthday Party

4. HALL OF ANCIENT EGYPT

Kids will walk like an Egyptian after exploring the Hall of Ancient Egypt in this Deluxe party! Click here for more information.

Success Kid Meme - Egypt Birthday Party

 

BONUS ADD-ON: SHARK! EXHIBIT PRIVATE TOUR

For a limited time, you can add a private SHARK! exhibit tour (complete with shark touch tank) to any HMNS birthday package!

Success Kid Meme - Shark Birthday Party

 

With all of these great options it’s no wonder why parents and kids alike love HMNS Birthday Parties! Book your 2014 party by September 15 and receive $50 off! Email Birthdays@HMNS.org or call 713-639-4646 to reserve yours today.

 

*To receive the $50 discount, your party must take place in 2014 and must be booked by September 15, 2014
**Some birthday party options are not be available at the HMNS Sugar Land location, please contact one of our Party Planners for more information at Birthdays@HMNS.org or 713-639-4646

Seeing Stars with James Wooten: The Equinox Approaches

This star map shows the Houston sky at 10 pm CDT on September 1, 9 pm CDT on September 15, and dusk on September 30.  To use the map, put the direction you are facing at the bottom.  The Summer Triangle is high overhead.  This consists of the brightest stars in Cygnus, Lyra, and Aquila.  Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to his left.  From the Big Dipper’s handle, ‘arc to Arcturus’ in the west.  Mars pulls away from Saturn in the southwest.  The Great Square of Pegasus is in the east, heralding the coming autumn.

This star map shows the Houston sky at 10 pm CDT on September 1, 9 pm CDT on September 15, and dusk on September 30. To use the map, put the direction you are facing at the bottom.
The Summer Triangle is high overhead. This consists of the brightest stars in Cygnus, Lyra, and Aquila. Scorpius, the Scorpion, is in the south, with the ‘teapot’ of Sagittarius to his left. From the Big Dipper’s handle, ‘arc to Arcturus’ in the west. Mars pulls away from Saturn in the southwest. The Great Square of Pegasus is in the east, heralding the coming autumn.

This month, Mars remains in the southwest at dusk this month as it pulls away from Saturn. Mars continues to fade a little each night as Earth continues to leave it farther behind. Mars is near Antares in Scorpius by the end of the month.

Saturn is now lower in the southwest at dusk. It drops into the Sun’s glare late next month.

Venus is now getting harder to see, as it will pass behind the Sun late next month. You can still look for it very low in the east in dawn twilight.

Jupiter is now higher in the east at dawn; it is the brightest thing there until Venus rises. 

The Big Dipper is left of the North Star, with its handle pointing up. From that handle, you can ‘arc to Arcturus’ in the west at dusk. 

Antares, brightest star of Scorpius, the Scorpion, is in the southwest, with the ‘teapot’ of Sagittarius due south. The Summer Triangle is high overhead. The stars of summer are here.  Look for the Great Square of Pegasus rising in the east, indicating that fall is approaching.

Moon Phases in September 2014:
1st Quarter:
September 2, 6:11 am
Full: September 8, 8:38 pm
Last Quarter: September 15, 9:05 pm
New: September 24, 1:12 am

At 9:29 pm on Monday, September 22, the Sun is directly overhead at the equator; everyone in the world has the same amount of daylight. This, then, is the autumn equinox.  For us the days, which have been getting shorter since June 20, actually become shorter than the nights after this equinox. In the Southern Hemisphere, day becomes longer than night and spring begins. 

Click here for the Burke Baker Planetarium Schedule. 

On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer. If you’re there, listen for my announcement.

 

 

Clear Skies!

STEM & GEMS: Chemical Engineer Stevie Showalter Talks Nerdy To Us

Editor’s Note: As part of our annual GEMS (Girls Exploring Math and Science) program, we conduct interviews with women who have pursued careers in science, technology, engineering, or math. This week, we’re featuring Stevie Showalter, ALLEX Program Participant for Air Liquide.

Nerd Alert

HMNS: How old were you when you first become interested in science/technology/engineering and/or math?
Showalter:
It was literally second grade when I first learned the word chemistry. Then I was hooked. I wanted to be a chemist until high school when my parents and teachers swayed me to chemical engineering.

HMNS: Was there a specific person or event that inspired you when you were younger?
Showalter:
I had two really awesome chemistry/science teachers and two really awesome math teachers that pushed me to do my best and learn as much as I could.

HMNS: What was your favorite project when you were in school?
Showalter:
I always LOVED science fair season! I didn’t do it in high school because it wasn’t offered, but in 8th grade I advanced to the regional level with my project. My project was the efficiencies of different light bulbs (incandescent, fluorescent, black light) by measuring the temperature they gave off.

HMNS: What is your current job? How does this relate to science/technology/engineering/math?
Showalter:
Currently I work as an engineer for Air Liquide in their rotational training program. My last rotation I worked at a primary production plant making liquid and gaseous nitrogen, oxygen, and argon by separating those elements from the air through cryogenic distillation. My rotation now is all about maintenance and reliability. I currently evaluate all the ‘mini’ plants (I guess you could say) that we have at customer sites to see how we can increase their productivity.

HMNS: What’s the best part of your job?
Showalter:
The fact that our product reaches soooooo many people. You may not know it, but our carbon dioxide is in Pepsi and Coke. Our oxygen is the supply at many hospitals. Our nitrogen helps make different products like tires, rubber, car seats, and so many other things!

HMNS: What do you like to do in your spare time?
Showalter:
Read, go on bike rides, try new things and travel!

HMNS: What advice would you give to girls interested in pursuing a STEM career?
Showalter:
Just keep going! It’s fun and exciting and so satisfying to see your math and science in action!

HMNS: Why do you think it’s important for girls to have access to an event like GEMS?
Showalter:
To encourage them to pursue their geeky interests! It’s ok to be a nerd sometimes! Nerds and geeks run the world! (It’s ok that I say this, because I’m quite a nerd/geek)