Buzz or flutter: Who matters when it comes to pollination? (Hint: It’s everybody.)

In economic terms, bees far outstrip butterflies and moths as pollinators. However, there are some plants that are exclusively pollinated by butterflies — especially some wildflowers and garden ornamentals — and several night-blooming species are specifically pollinated by hawkmoths.

Butterflies and moths are members of the insect order “Lepidoptera” — the scaly-winged insects. In addition to the scales covering adults’ wings, Lepidoptera have unique mouth parts as adults: a long, thin, double-barreled, flexible “straw” that is kept coiled up when not in use and extends to reach deep into flowers to extract nectar. This long proboscis means the plants that butterflies and moths typically pollinate have long, thin floral tubes, making the nectar inaccessible to other pollinators with shorter tongues, such as bees or flies.

courtesy of Wikimedia commons

The technical term for butterfly pollination is “psychophily” — psyche being Greek for butterfly.  Butterfly-pollinated flowers are usually brightly colored (butterflies have the widest-known range of color vision in the animal kingdom), especially in yellows, oranges, reds, pinks, and purples or combinations. Scent is apparently not important for butterflies.  However, the flower structure and position is important.  Butterfly-attracting flowers are often produced in showy terminal clusters of smallish blossoms, each with a floral tube that contains nectar and is easily accessible by the butterfly’s long proboscis.

Smaller flowers are usually pollinated by smaller butterflies, which have relatively shorter probosces; large butterflies such as swallowtails have very long probosces and a longer “reach.” Some familiar examples of “classic” butterfly-pollinated flowers are pentas, lantana (indeed many plants in the verbena family), thistles and coneflowers (and many other members of the sunflower or aster family), and milkweeds, among others.  Milkweeds are especially interesting as their pollen is not powdery but occurs in masses or pollinia, each of which bears a little hook that catches on a butterfly’s leg as it probes among the flower clusters.

A few butterflies (mostly the genus Heliconius in the longwing butterfly family) are known to collect pollen on their proboscis and absorb the amino acids from it.  In general, butterflies do not have the “carrying capacity” for pollen as bees do with their hairy bodies.  However, as they move from flower to flower, enough pollen accumulates on their legs or proboscis to get the job done!

Moth pollination is termed “phalaenophily” (phalaen- meaning moth). A number of moths, including tiger moths, noctuid or owlet moths, and more, visit flowers.  But the best-known pollinators among the moths are the hawkmoths, also known as sphinx moths — the adult form of hornworm caterpillars. These large, powerful fliers are basically the nocturnal equivalent of hummingbirds.  Hawkmoth-pollinated flowers are usually white or pale-colored, making them stand out from the surrounding vegetation at night.  They have long floral tubes to accommodate the very long proboscis of these moths, and many are highly fragrant in the evening, or may only open after dark.  Some examples are moonflower, Brunfelsia, Brugmansia and Datura, night-blooming jasmine, four o’clocks, and evening primrose.

Back to bees:  most of us think “honey bee” when we think of bees, but there are many other bee species, from the familiar bumblebee (not common in our area) to the giant carpenter bees, to tiny sweat bees and colorful leaf cutter bees. These different bee species also have favorite flowers to visit for nectar or pollen (most bees only collect pollen).  For the technophiles, pollination by bees is called “melittophily.”

The wonderful variety of flowers — their shapes, sizes, colors, scents and time of day they bloom, even their placement on a plant — have all evolved to attract a pollinator, often a specific one.  Since plants are rooted in the ground, they depend on things that move, mostly flying things — whether butterfly, moth, bee, fly, hummingbird, bat, or even wind — to transfer their male gametes (in pollen) from flower to flower so that the plants can make more of themselves through forming fruits and seeds.

Next time you are out in your garden, in a field of wildflowers, in a gardening shop, or any place with an abundance of flowers, stop to look more closely at the blooms and think about what pollinator that plant might depend on for its survival.

Bountiful butterflies plus more on moths: Why you should appreciate both this summer

Houston is brimming is with butterflies this season! Moths, too.

After a dismal showing during last year’s prolonged drought with almost no butterflies at all, this year local butterflies have bounced back with a vengeance! Or maybe “vengeance” isn’t a word usually associated with butterflies. In any case, there are lots of them.

gulf frit1A Gulf Fritillary

I have never seen so many butterflies in my backyard garden – both as babies (caterpillars) and adults. Pipevine swallowtails are particularly abundant right now, and I had dozens of monarchs a few weeks ago. I’ve seen black swallowtails and giant swallowtails, gulf fritillaries, and a few sulphurs as well. I just acquired three small sassafras trees, and they came complete with a couple of my favorite caterpillars: the spicebush swallowtail, which are the inspiration for the giant caterpillar sculpture at the Cockrell Butterfly Center entrance. And I’m not the only one who is seeing an abundance of butterflies; many Houston gardeners have made similar observations.

spicebush cat2A Spicebush Swallowtail caterpillar

In addition to these garden species, I’ve noticed big numbers of some of the forest-inhabiting butterflies such as hackberry and tawny emperors, question marks, and red admirals. These butterflies typically visit sap flows or rotten fruit, and their caterpillars eat hackberry or elm leaves (or nettles, in the case of red admirals), so to see them you need to take a walk in the wood. I take my dogs walking at “Wortham Island,” a former oxbow bend of White Oak Bayou that is now an off-the-beaten-path wooded area in northwest Houston, and have seen clouds of emperors, lots of question marks, and a red admiral or two. Snout butterflies, another species more common in wooded areas, have appeared in my yard for the first time, sipping water off the sidewalk.

emperors feeding
Tawny emperors feeding

And a new butterfly species may be on the horizon! As we reported in the latest Museum News, a zebra swallowtail (Eurytides marcellus), until now unknown in Houston, was spotted laying eggs on paw paw plants at a local nursery. Hoping that this sighting might not be a complete accident, I’ve planted a couple of paw paws in my yard, and am keeping my eyes open and fingers crossed. Zebra swallowtails are fairly common in the Big Thicket area, less than 100 miles northeast of us. I’ve always said that if people from Cleveland, Texas to Houston would just plant paw paws, we could probably bring this gorgeous butterfly to our area!

Eurytides marcellusZebra swallowtails may be migrating to Houston

On the down side, I have not seen any orange-barred sulphurs for a couple of years, and the polydamas swallowtails, which seemed to be overtaking the pipevine swallowtails, have also been less visible.I’m guessing that the cold winter of 2010-11 may have knocked back the populations of these tropical species, and they haven’t made it back in large numbers yet.

So why is this year so good for butterflies? I can only guess that the weather conditions have been just right this spring and early summer. We’ve had enough rain and lots of warm, sunny weather in between. Certainly all the interest in planting for butterflies can’t hurt. The only reason there are so many pipevine swallowtails and monarchs in my yard is because I’ve had dozens of their caterpillars eating all the Brazilian pipevine and Mexican milkweed I’ve planted. Providing host plants is vital. Of course, where I’m seeing the butterflies now is at the pentas and Mexican bauhinia that are blooming profusely these days, so nectar plants are important too!

pipevine cats1
A Pipevine caterpillar

On a different note – but still keeping with the lepidopteran theme – there is a wonderful new Peterson Field Guide available on moths of northeastern North America. Unfortunately it is NORTHeastern – but many of the species portrayed in the excellent illustrations do occur in our region. I highly recommend adding this book to your library. Moths may have more subtle coloration than butterflies, but many are quite spectacular mimics of lichen, bird droppings, leaves, or other insects. And although a few are pests of forest trees or in the garden, most are harmless and are important sources of food for bats (as adults) and songbirds (as caterpillars).

I was interested to read in the moth book introduction that there is a citizen science program on moth-watching in Great Britain. So little is known about our moth fauna here in the USA; it would be great if something similar could be launched here. Did you know that there are about 15 to 20 times as many moths as butterflies? In North America, there are about 11,500 moth species to 725 butterfly species. Perhaps with the availability of books like this one, people will start to pay more attention to these poorly known and poorly understood creatures. All it takes is leaving your porchlight on and observing (and trying to identify) the nocturnal creatures that are attracted to it. But be aware that some of the most colorful moths fly during the day.

Another useful thing to do where moths are concerned is to rear the caterpillars you find. Just because they don’t turn into beautiful butterflies does not mean they are not interesting in their own right! Do keep a record of the host plant the caterpillars eat.

Long live the Lepidoptera!

Cockrell Butterfly Center Spring Plant Sale

Spring is almost here!

Of course it has felt like it for months now, but with all of the rain we have had lately, we should have a good show of blooms. And with the blooms come the butterflies. Most of the time, butterflies get most of the attention, but have you ever thought about creating a moth garden. Why moths? There are approximately 11,230 identified species of Lepidoptera in North America. Almost 90% of those are moths. Now, while most moths can appear small and drab, even serve as pests for some plants, there are some very interesting and beautiful species of moths. For example, Hawk or Sphinx moths (sometimes even called Hummingbird moths because of their large tapered bodies and hovering flight) are large and sometimes showy with interesting, cryptic patterns adorning their wings.

 Their caterpillars look similar to the Spicebush Swallowtail with their large eye spots and chunky bodies.

They feed on a variety of plants, but what I see the most are Tersa Sphinx moths (Xylophanes tersa) because they eat the leaves of Pentas (a very popular nectar plant for butterfly gardens). So think of those Pentas as two plants in one, nectar and host! The adults are seen mostly on white flowers that bloom (or stay open) at dusk. Moon Vine, Cestrum, Jasmine, Rangoon Creeper and Evening Primrose are all recommended as excellent moth attractors!

Most other showy moths like Polyphemus, Luna, Cecropia, IO, and Imperial moths are in the Giant Silkworm family (Saturniida) and do not feed as adults because they do not have mouthparts. Their host plants are trees, mostly Oak and Hickory related species, so it is kind of hard to find their caterpillars. If you do, you are lucky! Some of the most beautiful and impressive caterpillars are from Saturniid moths. The adults are attracted to bright lights at night, so this is a possible way of encountering them.

Polyphemus Moth

The spring plant sale for the Cockrell Butterfly Center is a one stop shop for any butterfly (and moth) plants you need. We will have the standard, reliable plants that every butterfly garden should have, like Porterweed, Mexican Milkweed, Brazilian Pipevine, several Passion vines, Mexican Bauhinia, Pentas and more. This year we also have some different natives to share with you. We will have Salvia azurea (Pitcher Sage), Cirsium texanum (Texas Thistle), Simsia calva (Bush Sunflower), Castilleja (Indian Paintbrush) and Eupatorium greggii (Gregg’s Mistflower). Some non-native, but excellent butterfly plants that we will also have are: Tithonia (Mexican Sunflower), Celosia spicata (Cramer’s Amazon Celosia), several types of Gomphrena (Bachelor’s Buttons) and many many more!

Cramer's Amazon Celosia

The spring sale is Saturday, March 31st, 2012 from 9am to noon. Located on the 7th level of the museum parking garage. We accept cash, check and credit. Come early and bring a wagon!

Photo from You: Insect Identification

Last week we received a photo of a very bizarre looking insect from Melissa who lives in the Seattle area. I had an idea of what it was when I opened the file, but it was a bit of a head scratcher!

For the most part, all insects in a particular order share the same distinguishing characteristics and it’s easy (for me) to tell what group they belong to. Grasshoppers look like grasshoppers, butterflies like butterflies, wasps like wasps, etc. But there are some exceptions to the rule. Some moths mimic beetles, some flies mimic bees, and some insects just look like 3 different things at once! This was the case with the bug Melissa found.

Photo by Melissa Mashock

It is a very alien-like creature called a plume moth. Plume moths do not look like the typical moth or butterfly. But then again, since there are about 250,000 species (10 times the amount of butterflies) of highly variable insects known as moths, there really isn’t a typical moth.

At first glance, a plume moth resembles a crane fly. You know those large clumsy flies you see in the spring, whose legs fall off if you look at them wrong. They have very thin wings that are divided into lobes. The forewings typically consist of two lobes and the hindwings have 3.  At rest, many species hold their wings straight with the lobes folded together, making them look like a “T.” There are 154 species of these moths found in north America, making species identification very difficult and often requiring a microscope. The adults are quite inconsequential and can go relatively unnnoticed. They’re often mistaken for a bit of dead grass! This allows them to be easily overlooked by potential predators and most other things.

Luckily Melissa noticed this one enough to snap a picture so we could learn about this cool insect. The caterpillars are the most significant life stage and can be pests on some crops such as artichokes and ornamentals such as geraniums and snapdragons. On the other hand, they have been used as biological control to combat invasive plants such as West Indian lantana.

Photo by Melissa Mashock

Even though I’m an entomologist, there are a million described species of insects, most of which I’ve never seen. I always love the challenge of identifying different species that people find in their particular corners of the world. Then I can add another species to the list of ones I know about. And by reading, you can too!

I encourage everyone to spend some time outside observing the smaller things that are out there. If you find something that interests you, snap a picture, and send it in to blogadmin@hmns.org. We love to receive these kinds of queries! We’ll identify and feature your bug in our blog.

Until next time, happy bug watching!