Seeing Stripes: The Zebra Longwing Butterfly

The zebra longwing (Heliconius charithonia) is a common resident of the Cockrell Butterfly Center (CBC). This butterfly is easily recognizable with boldly striped yellow and black wings. When visiting the CBC, you’ll often spot them sipping nectar from the flowers and nectar feeders or sunning themselves with their wings spread open. These butterflies have some unique features and behaviors that set them apart form the rest!

Aposematic Coloration

Bright, contrasting warning colors are known as aposematic coloration. They indicate to potential predators of the “unprofitability” of a prey item. The bold yellow and black stripes on the zebra longwing serve as a warning signal to potential predators of the butterfly’s unpalatable and poisonous nature. Zebra longwing caterpillars feed on passion vine (passiflora) leaves and acquire some of their toxins, making them distasteful to predators. 

zebra

Bright, contrasting colors warn predators to stay away.

Pollen feeders

Most butterflies can only sip fluids with their proboscis, most commonly flower nectar. Zebra longwings, on the other hand, also feed on pollen. They use their saliva to dissolve the pollen and take in its nutrients. Pollen, unlike nectar, contains proteins and is very nutritious. Pollen feeding is correlated with overall higher fitness. This diet allows zebra longwings to live longer (up to six months) and increases females’ egg production. 

zebra pollen face

You can see pollen on this zebra longwing’s proboscis. Feeding on pollen increases longevity.

Pupal Mating

Male zebra longwings exhibit pupal mating, zebra_longwing_and_chrysaliin which they will mate with a female before and immediately after she emerges from her chrysalis. Males will seek out a female pupae and will perch on it and guard it from competing males. Many males may fight for the opportunity to mate with the yet-to-emerge female. The successful male will insert his abdomen into the softening pupae and copulate with the female. Mating will continue as she emerges and dries her wings. The males will pass a nutrient-rich spermatophore to the female which reduces her attractiveness to future mates. This male (at right) begins mating with the female before she has even emerged from her chrysalis.

zebra_longwings_mating_elizabeth

This mating pair shows the freshly emerged female still clinging to her chrysalis.

Communal Roosting

Adult zebra longwings roost communally in groups of up to 60 individuals at night. They tend to return to the same roost on a nightly basis. In the late afternoon, zebras can be observed fluttering and basking near their roost site as they slowly gather together for the night. Roosting together provides protection from predators and retains warmth. 

zebra-longwing-roosting-fmel-9

These zebra longwings are preparing for the night by roosting together for safety.

So now you know! These beautiful, brightly colored butterflies are bad-tasting, and long-lived. They have unique mating habits and the snuggle together at night. Something to remember next time you visit the zebras at the CBC!

Insects and Orchids: An Evolutionary Journey

I absolutely love orchids! I mean who doesn’t, really? They are my very favorite flower in the whole world. I can literally stare at them for hours and not get tired of them. I love to photograph them; I even had them in my wedding! I love their colors, their shapes, there is really no flower quite like the orchid.

Well, if you love these flowers as I do, I’ve thought of another reason for you to love insects! We would not have the amazing shapes, the striking colors, or the unique fragrances from orchids if it weren’t from our amazing little friends!

Orchids are an ancient flower – appearing some 80 million years ago, during the time of the dinosaurs – much older than scientists first believed. They flourished, as many organisms did, after the big extinction and began to figure out how to best survive in this new world. They can grow on every continent except for Antarctica and in almost every type of habitat. They can grow as epiphytes, attached to trees or shrubs, lithophytes, attached to rocks, or they can be terrestrial like most other flowers. They also figured out, because plants are very smart you know, that cross pollination, as opposed to self pollination, is the best way to survive. What is the best way to cross pollinate? With insects of course. So began an intricate process of co-evolution between these amazing flowers and their insect counter-parts.

Co-evolution can be defined simply as the change of a biological object over time that is triggered by the change of a related object. So, as the insects changed, so did the orchids which were dependent upon them. This has led to an incredible amount of diversity in the 25-30,000 species of orchids that exist today. Charles Darwin studied orchids and their relationship with insects; he developed this theory of co-evolution based on his findings. He introduced the theory of plant and insect interactions in his book, On the Origin of Species. Later, he published Fertilisation of Orchids, which explained in detail the complex relationships between these flowers and the insects that pollinate them and how this led to their co-evolution.

A Cocytius antaeus, the new world equivilant of the
Xanthopan morgani.

Today, this can be seen more than ever with some extremely unique orchids and their very interesting, and sometimes weird, ways of attracting insects. One of the most compelling pieces of evidence of this co-evolution is Angraecum sesquipedale or, Darwin’s Orchid in Madagascar. Darwin noticed that this orchid had an extremely long spur, so long that only an insect with a very long proboscis could reach the nectar inside. He actually predicted that there was an undiscovered moth out there with a foot-long proboscis that could pollinate this orchid. Well, he was right, and now we have Xanthopan morgani or the Morgan’s sphinx moth. This incredible moth was not discovered until 1903, but proved Darwin’s theory and was originally named Xanthopan morgani praedicta in honor of his prediction. The moth has an unbelievably long proboscis which can reach down into the flower to retrieve the precious nectar. In doing so, the moth rubs its head against the pollen producing organ of the plant and transfers the pollen to the next flower it drinks from.

(un)natural encounter
Creative Commons License photo credit: avmaier

Many other orchids use specific fragrances to lure insects. Some use sweet fragrances to attract certain bees and wasps, and others, putrid smells to attract flies. These happy insects are rewarded for their pollination with yummy nectar. Others use striking colors that flying insects can’t resist. Still others, about 1/3 of all orchids, produce no nectar. These have come up with some pretty tricky methods of attracting insects. These are some of the most specialized orchids of all. Some mimic the smell of food. Flying insects approach the flower and crawl all over it looking for the nectar. It is not until they are covered in pollen that they give up and move on to the next one, transferring the pollen in their search for food.

Even more deceiving are the orchids that use sex pheremones to attract unsuspecting pollinators. These orchids are amazing. They actually mimic the female bee or wasp visually, often using the same colors and tufts of hair. They give off a chemical that smells identical to the pheremone that the female insect would give off. The poor males climb on the flower, actually try to mate with it (sometimes leaving behind sperm) and move on to the next, spreading the pollen. What a smart flower! Watch this video to see a great example of this type of orchid.

Stemless Lady-slipper
Creative Commons License photo credit: *Micky

One last amazing orchid/insect relationship. The lady’s slipper orchid is a very unique looking flower. With a pouch-like structure, it resembles a pitcher plant, which is a known insect-eating plant. The pitcher plant uses its pouch to lure in insects which fall in and are digested inside. The slipper orchid, however, has a much more benevolent agenda. The pouch does lure insects, they do fall down inside, but they do not meet their doom there. The pouch is too small for the insect to stretch its wings so they cannot fly out. The only way out is to climb a ladder of hairs on the back. The insect must squeeze past where the pollen is kept to get away. They either leave with the pollen, or leave another plant’s pollen there, tricky tricky!

So, you see, if you’ve never thought of plants as intelligent, you may want to think again. Exquisite, exotic, luxurious, stunning, elegant, whatever term you use to decribe orchids, you can now add intelligent and highly evolved. I hope this gives you a whole new respect for these famous flowers, and the bugs that make them what they are!

If you like orchids and want to learn more about them, don’t miss the Houston Orchid Society’s upcoming Show and Sale, which will be held at the museum this year. It’s free! Saturday and Sunday only, April 17 & 18. For more info, visit our web site.

Your Friend: The Roach

A family out for a bite to eat.

A family out for a bite to eat.

Often dogs are credited as “man’s best friend,” but I beg to differ.  I offer you instead the humble roach. 

The usually and immediate reaction to the word “roach” (or the actual specimen) is disgust and panic.  I will fully admit that I don’t love them in our garage and that they give me the creeps when they skitter across the driveway, but I DO enjoy not being waste high in detritus.

Cockroaches are nature’s decomposers and are essential for returning nutrients to the soil.  They take one man’s trash – namely, yours – and turn it into little ecological treasures.

Additionally, roaches make tasty treats for reptiles, amphibians, fish, birds, other insects, and several mammals.  Not surprisingly, humans don’t love them (but have been known to eat them, though not frequently).  This is not because humans don’t like to eat bugs, but rather because of the particular taste of roaches which is similar to ammonia.  If you ever do decide to partake, know that they have three times as much protein as chicken.

Roaches are also good pollinators.  In fact, the first pollinators were beetles, not bees.  They are also the most frequently used speciments in the study of insect behavior, anatomy and physiology.

So in review, if you DON’T like being waste high in debris, but you DO like growing plants and eating, you must love the roach.

Do the butterflies breed? Your butterfly questions, answered

For this blog, I thought I would share with you and answer some of the most common questions we get here in the Cockrell Butterfly Center, specifically related to butterflies.  The question that we get asked the most, by far, is:

“How long do the butterflies live?”
Well, typically they live in our center for about two weeks, but there are a few exceptions.  The longwing butterflies, in the genus Heliconius, can live for months.  They not only feed on nectar, but also pollen.  They extract very nutritious amino acids from the pollen, which allows them to live longer.  Another butterfly that seems to live a long time is the rice paper, Idea leuconoe.    

“How many butterflies do you have in here?”
There are anywhere from 1,500 to 2,000 butterflies flying through the Butterfly Center at a time.  On really, bright sunshine-y days when the butterflies are very happy it seems like there are way more than 2,000 and on gloomy cloudy days the butterflies hide and it seems like there are fewer than 1,500. 

“What is that liquid in the red bowls?”
That is our butterfly feed.  We cannot always guarantee fresh nectar from blooming flowers to the butterflies, so we supplement them with this instead.  It is a mixture of 4 parts water to 1 part sugar with a cap full of amino fuel.  Many people ask me if they can make a similar set up to put in their yard.  Absolutely! But, do be prepared for ants and bees to take advantage of the nectar as well as the butterflies.


“Why do you have fruit and nectar for the butterflies?”
Some butterflies are nectar feeders and others are not.  Most of the butterflies that do not drink nectar are fruit feeders.  We like to give our butterflies a variety of tropical fruits, including kiwi, papaya, mango, cantalope and honeydew.  They especially love super ripe black bananas and on occasion they get starfruit, which we pick from our tree in the butterfly center. 

Some male butterflies, especially swallowtails and sulphurs, will do what we call “puddling.”  They are attracted to salts and amino acids in mud and will actually drink from it, sometimes in very large numbers called a “puddle club.”  It is thought that the males benefit from the salts, increasing their reproductive success – but of course it is not known for sure and scientist are still trying to work out the reason. 

Some butterflies are also attracted to tree sap, carrion, and dung.  Sometimes our iguana, Stretch, will leave some excrement behind and – low and behold – a butterfly will land on it and start drinking.  We have even thought about collecting some iguana poop and putting it in a huge pile for the butterflies – but we eventually decided against that.   

“Do the butterflies breed in here?”
The butterflies are free to mate but due to USDA regulations we are not allowed to provide them with host plants.  Female butterflies will only lay eggs on a specific plant that her caterpillars can eat, so we have to make sure that no host plants are in the butterfly center.  This involved alot of work when we first opened because we have so many species of butterflies and they do not all feed on the same plant. 

The reasoning behind this policy is that the USDA believes that the escape potential of a caterpillar is greater than that of an adult butterfly; if the butterflies were allowed to lay eggs, then there would be caterpillars everywhere, and the chance of someone leaving with one on them would be pretty high. 

Another obvious reason that we do not want caterpillars is that they would eat all our beautiful plants.  Now, just because we do not want caterpillars in the butterfly center doesn’t mean we do not like them.  Caterpillars are so much fun to have in your garden.  If you plant the correct host plant, you can attract native butterflies to your yard.  You can find a list of host plants that you can plant in Houston by clicking here.

“Why won’t that butterfly leave the other one alone?”
The butterflies in this video represent this question (It’s not the best quality, so sorry!).  These butterflies are courting.  Although they look like different butterflies, they are subspecies of the same species, Heliconius erato.  The male is flying above the female trying to entice her to be his girlfriend with his wonderful smell.  Sometimes the female is so attractive that two or three males will be courting her.  This behavior can almost always be viewed in the butterfly center – you just have to look for it. 

Another courting behavior that is encountered a lot is two butterflies chasing each other.  They will flutter around each other in circles, resembling a graceful rehearsed dance.  This normally happens in a nice sunny area, so look for it next time you are here.

Well, I hope you enjoyed my question/answer session.  If you have any questions please feel free to ask in the comments and I will be happy to answer!

Want to learn more about butterflies and host plants?
Where do all the butterflies from the Cockrell Center come from?
Learn more about the Luxurious Longwing butterfly.
Read about Suplhur Butterflies.