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!

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.   

Fall Butterflies in Houston

Last week I gave a workshop/lecture at the Houston Arboretum about “Butterflies of Houston.”  I had not chosen the title, and confess I was a little nervous about the emphasis – I can hold my own talking about butterflies in general, and especially about Central American butterflies, but I am not an “expert” on the local species.  Especially not the “LBJs” (little brown jobs; mostly skippers) of the butterfly world!  However, I put together my slides and gathered some field guides and hoped for the best.

It was a fun class.  The participants (regrettably, only about 9 people) were interested, knowledgeable and enthusiastic about their own butterfly gardening and viewing attempts.  We decided to go ahead with the scheduled field trip on Saturday even though the weather prediction was for possible rain.

spicebush swallowtail larvae
Spicebush Swallowtail Caterpillar.

It was overcast but not raining as we gathered in the Arboretum parking lot.  No butterflies were flying, but one of the participants quickly pointed out a smallish camphor tree that had the characteristic rolled leaves housing my favorite caterpillar, the spicebush swallowtail.  These adorable creatures look like toy snakes – they are bright green with large eyespots on their thorax.   A discussion ensued as to why some of the participants had never had spicebush caterpillars on THEIR camphor (or sassafras) trees.  We concluded (or at least I concluded) that the female butterflies really seem to seek out small trees – young saplings, not mature trees.  Perhaps the young trees haven’t yet upped their levels of caterpillar-deterring chemicals, or perhaps their leaves are more tender.  Or perhaps the caterpillars are simply harder to find on larger trees.  And besides, the butterflies really do seem to prefer the hostplant they are named for – spicebush (Lindera benzoin) – but it really doesn’t do all that well in our area.  In any case, I have noticed the same pattern (more caterpillars on small/young plants) in the citrus-feeding giant swallowtail as well.

Not finding much more in the parking lot, we wandered down the Outer Loop trail to the Meadow.  I had hoped to see a few forest butterflies such as tawny, hackberry emperors, red admirals, or even goatweed leafwings, along the Loop Trail, but no such luck.  However, soon after arriving at the Meadow, I was very excited to find caterpillars of the goatweed leafwing on the Texas goatweed (Croton capitatus, aka hogwort or woolly croton) plants growing abundantly along the roadside edge.  Like spicebush caterpillars, these guys hide in rolled up leaves of their hostplant during the day.  However, in contrast to the whimsical spicebush cats, leafwing catepillars are rather drab, greenish with whitish bumps on the body, and a slightly warty, dark head.  And, they spit copious amounts of bright green fluid when you try to unroll them!  I complained to my companions that I had just pulled two large goatweeds out of my garden after waiting all summer for caterpillars!  Perhaps I had given up too soon, or perhaps one needs to be closer to a forest habitat as a source of the egg-laying females.  Who knows? (This could be tested, however, if someone wanted a definitive answer!)

gw leafwing frass chain

But back to the caterpillars:  another cool thing about leafwings is the unique “frass chains” that the caterpillars make when they are very small.  This damage is also characteristic of tropical members of this family, and I have seen it often in the field – often the first clue that a caterpillar is on a given plant.  What IS a frass chain?  First of all, you should know that “frass” is the technical (and very nice, I think) word for “insect pooh.”  The tiny caterpillars eat the tip off a leaf, leaving just the midvein.  They then use their silk (all caterpillars have silk-producing glands in their mouths) to glue tiny pieces of their excrement (frass) to the end of the midvein, elongating it by as much as ½” (it helps to have a hand lens or magnifying loupe to see this).  They also sometimes glue random bits of dead leaf material along the midvein higher up.  Then, during the day, the little caterpillar, which is about the color of a dead leaf bit itself, sits at the end of the frass chain, hidden in plain sight.  So clever!  When it gets larger it moves into a rolled leaf (also held together with a bit of silk).

gulf fritillary Agraulis vanillae
Gulf Fritillary, Agraulis vanillae.

We then noticed the much showier, spiny black and orange caterpillars of the most common butterfly we saw that day, the spectacular gulf fritillary.  Gulf frits, like all members of their subfamily (the longwing or passionflower butterflies) eat passionflower vines as caterpillars.

caterpillars
Gulf fritillary caterpillars on passionflower vine

And there was plenty of the native Passiflora incarnata, or maypop, growing in the Meadow.  The butterfly itself is one beautiful bug, especially the males, which, like many other butterflies and songbirds, are more brightly colored than females.  Males are a brilliant orange above, with a few black spots; females are similar but a duller orange.  The underside of both has sunrise-like hues of pinkish orange on the upper wing, and spots of silver (yes, silver!) spots spangling the lower surfaces of both fore and hind wing (rendering the butterfly very difficult to see when perched in the vegetation).

buckeye cat

We also saw several buckeyes, one of our prettiest butterflies, with large eyespots and multi-colored patterns in brown, purple, orange, and blue on the upper wing surface.  The underside is quite drab and cryptic – it is hard to imagine it is even the same butterfly (but this is true of most butterflies, that the underside is drab or camouflaged no matter how showy the upperside).  We found buckeye caterpillars too, blackish and spiny, easy to see on the slender upright stems of their hostplant, Agalinis fasciculata or false foxglove.

I was determined to identify some skippers, even though this large group of mostly small, mostly brown, mostly very fast-flying butterflies had heretofore been a bigger challenge than I wanted to take on.  But I had my reputation to uphold!  We did come across several individuals, and luckily the group was patient as I flipped through the field guides.  Eventually we managed to identify to all of our satisfactions the skippers we saw, including a clouded skipper, an ocala skipper (we think), and a fiery skipper.  Much easier to ID was the showy (in skipper terms) white-striped longtail – the brilliant white stripe on the underside showing clearly when it perched to sip from the lavender blazing star (Liatris) or ironweed (Vernonia) flowers blooming profusely in the Meadow at this time.

scoliid waspWe did not see any blues or hairstreaks (well, I saw a tiny Ceraunus blue and a gray hairstreak after the group had left) but we did see several other interesting insects.  A pretty scoliid wasp – metallic black with bright creamy white spots on the abdomen – was very interested in the abundant flowers of late-flowering Boneset (Eupatorium serotinum). This native plant looks like a weed except when it is blooming, as it does only at this time of year.  Its tiers of small, fuzzy, white, fragrant flowers attract many small butterflies, especially hairstreaks and skippers, along with other insects including wasps, flies, and ermine moths.  On the goatweed we encountered several groups of a funny little bug (a hemipteran, or true bug) that looked much like a Volkswagon beetle.  The nymphs were gregarious, huddling in groups of 5-8 individuals.  When we disturbed one group, they followed each other in a little train until they found a new place to rest. 
goatweed bugs

Finally we saw a really big butterfly – the powerful and dramatic spicebush swallowtail, which we were able to identify on the wing (it never landed) as a male because of the greenish (rather than bluish) wash of scales on the upper side of the hind wing.  A gorgeous butterfly.  On a sunnier day we might have seen other swallowtails – probably giants, possibly pipevines, perhaps Tiger swallowtails, which I have seen at the Arboretum on other occasions.

Carlos Hernandez
Male Spicebush Swallowtail Butterfly.
Photo by Carlos Hernandez.

In sum, although we didn’t see hordes of butterflies, we all agreed it was a pleasant and productive outing, and finding all the caterpillars bodes well for the coming weeks.  After our relative success identifying skippers, I am ready to get out on a sunnier day when more are flying – and tackle more species!

Note:  If you are interested in watching butterflies, you should invest in a pair of close-focusing binoculars.  These are now widely available.  The difference between regular binoculars and these is that the closest you can focus with regular binoculars is about 10 feet or so – with close focus you can get to within 4 feet of your subject.  This is especially useful for observing small things like insects.  Both kinds are equally good for focusing on things far away, so you don’t lose anything by choosing close focus.

You will also want a field guide or two.  Although not really a field guide, I recommend John and Gloria Tveten’s “Butterflies of Houston and Southeast Texas” – it has gorgeous photos of adults and often the caterpillar stage, and tons of good information about the habits and habitats of most of our local butterflies.  You should also pick up either the “Kaufman Field Guide to Butterflies of North America,” or Jeffrey Glassberg’s “Butterflies through Binoculars:  the East.”  These are much less detailed than the Tveten’s work, but are much more comprehensive (and useful not just in Houston). Those of you who really get into caterpillars will want a copy of David L. Wagner’s “Caterpillars of Eastern North America.”   This book has fabulous photographs of nearly 700 caterpillars of both butterflies and moths, with a small illustration of the resulting adult, and nice descriptions of where the caterpillars are likely to be found and what they eat.  And don’t miss Wagner’s wonderful enthusiastic preface and introduction, which include all sorts of fun and useful information.

The next few weeks should offer prime butterfly watching.  So get out there – on a sunny day almost any area with some natural habitat and blooming plants should yield butterfly results!