Author Archives: Nancy

About Nancy

Nancy is Director of the Cockrell Butterfly Center and curator of entomology. A plant ecologist by training, she specializes in the interaction between insects, especially butterflies, and plants. The tropics are her favorite habitat, and she heads south to Central and South America whenever possible.

Cold Snap Raises Concern: How will the monarchs fare?

Published by on in Science
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Should I be concerned about the monarch butterfly?

Is it going extinct?

Will these cold temperatures kill the ones I’m raising?

What is “OE” and should I worry about it?

If you have questions about monarchs, you are in good company.

Thanks to the recent petition to US Fish and Wildlife by a number of conservation organizations to grant them “threatened” status, monarch butterflies have been in the news a lot this fall. Also, more and more people are hearing about the protozoan parasite that affects monarch health, the dreaded OE (short for the unpronounceable and unspellable “Ophryocystis elektroscirrha”). Finally, if you are in Houston, or other areas with monarch butterflies that do not migrate but spend the winter here, you may have questions about what this unusually early and unusually cold snap will have on the caterpillars and adults in your garden.

This is a quick response to all of those issues:

  1. Monarch butterflies are not in any sense endangered. The species is very widespread, found throughout the world, from Australia to southern Spain, Hawaii, etc., etc. What the groups petitioning for threatened status hope to achieve is to bring awareness to the possible end of the huge annual migration that takes place in the North American populations. Within the past decade or so, the number of individuals making the southern migration to overwintering grounds in Mexico has declined by about 90%. This is indeed worrying, and it would be a terrible loss if this unique and spectacular phenomenon ended. But there will still be monarchs – just not as many (millions instead of billions) and perhaps only non-migratory ones in areas where they can survive year-round. The decline in the North America population is thought to be due to a number of factors – the main one being loss of habitat. Genetically modified corn and soy beans have been bred to resist herbicides such as RoundUp, so farmers can spray their croplands for weeds (including milkweeds) and not affect these GMO crops. Until the widespread use of GMO crops, milkweed was abundant in the rows between plantings and in the highway right of ways.  Thus the huge expanse of farmland in the central USA cornbelt was critical in building up their populations during the breeding season (summer).  GMO crops, and subsidies for ethanol (which encourage corn farmers to plant every bit of their land, right up to the roadways) mean that this “cradle” of monarch populations is no longer available. There are other factors causing the huge decline in the migratory population – global climate change, urbanization, some habitat loss in Mexico – but this, i.e., habitat loss in the central USA, is the main factor. We do not know yet whether monarchs will be designated as “threatened” – such proposals take a long time to go through the various review processes. The good news is that this petition is raising awareness about this worrying loss of habitat – which affects not only monarchs, but bees, other butterflies, and many other organisms.

  1. “OE” is a naturally occurring protozoan parasite of monarch and queen butterflies (genus Danaus). This tiny organism multiplies inside the caterpillar stage, and is spread in a dormant spore form by the adult butterfly. Low levels of OE do not greatly affect their hosts, but parasite levels build up rapidly over successive generations of monarchs, and when infection levels are high, many detrimental effects (including death) are seen. Infected caterpillars may not pupate properly, or they may not be able to get out of the pupa, or the adults may be weak, malformed, or die early. Unfortunately, well-intentioned people raising successive generations of monarchs, especially on tropical milkweed (which does not have an annual dormant period) appear to be the main cause of OE buildup (via the very persistent spores).

    In areas like Houston, where mild temperatures allow for resident, non-migratory populations year-round, researchers have found that most adult butterflies are carrying the spores (i.e., over 75% of the butterflies they test are infected). For more information, visit the Monarch Watch organization’s website or click here for more information from the University of Georgia.

    You can also find plenty of information by doing an online search for Ophryocystis elektroscirrha.

  1. You raise monarchs and are concerned about whether they can survive the cold temperatures we’ve been having.

    The whole “point” of the monarch migration is to avoid cold temperatures – monarchs are really tropical butterflies that, like many songbirds, take advantage of our summers. However, in our area where it seldom gets truly cold, and where there is now lots of tropical milkweed available, thanks to the butterfly gardening craze, some monarchs forego the migration and spend the winter here, where they continue to breed (the migrating monarchs do not mate or lay eggs until spring). 

    Cold enough temperatures can certainly kill or harm monarchs, especially in the caterpillar stage or if they are in the process of pupating. However, unless it freezes and/or the caterpillars, pupae, or butterflies are highly exposed, monarchs can survive temperatures in the 30s. 

    During a cold snap, caterpillars will often crawl to the base of the milkweed they are eating and curl up on the ground until it warms up again. Adult butterflies can hunker down in a sheltered area and will come out again when it’s warm enough to fly. But if it’s cold enough for long enough, they will die. Of course it’s hard to tell people to let nature take its course — but that is probably best — especially given the high levels of OE we see in most people’s home-grown monarchs. If you do want to save your babies, you can always bring them inside for a few days until it warms up. 

    Butterflies can be fed sugar water, Gatorade, or fruit juice (place them with their feet touching a sponge or paper towel moistened with one of these sweet fluids and they will probably extend their proboscis to get a meal. If you would like to test to see if your butterflies have OE (only the adults can be tested), click here to learn how to do it. We (at the Cockrell Butterfly Center) would be happy to look at your samples, or you can send them to the University of Georgia.

If you have questions that were not answered here, feel free to write us at bfly-questions@hmns.org.

 

 

 

Mean green flying machines: the hummingbirds are here!

Published by on in Zoology
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Photo by JC Donaho. http://jcdonaho.com/

Photo by JC Donaho. http://jcdonaho.com/

What was that high pitched chirping and flash of iridescent green that just whizzed past at lightning speed? You just got buzzed by a hummingbird! The fall migration is passing through Houston, and these feisty little birds seem to be particularly abundant this year. Houston does not have (for the most part) any resident hummingbirds, but a few species pass through in spring and fall as they fly between their nesting grounds in the northern states and Canada, and their wintering ground in Central America.

The northward spring migration is much more diffuse than the fall event – you may hear a hummingbird or two in February or March, but they don’t linger. However, in late August through September and into early October, hummingbirds can be very evident in Houston. These marathon travellers will pass through our area for about 4 to 6 weeks, stocking up on fuel to take them over the Gulf of Mexico to their winter abode. They are particularly abundant on the Gulf Coast, where inclement weather can force them to stay put until a more opportune time comes to complete the migration. Rockport, Texas hosts a huge “Hummerbird Festival” every mid-September, with lots of talks on hummingbirds and other birds, butterflies, etc., and home tours to see gardens that are particularly full of hummingbirds. It’s over for this year, but put it on your calendar for future years and check it out!

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Most hummers you see in Houston (and in Rockport) are Ruby-throated Hummingbirds. Males are a metallic green with white bellies, and are named for the patch of dark feathers on their throat that glows a brilliant, iridescent ruby red when the sun hits it just right. Females and immature males do not have the spectacular throat coloring, and are white underneath. Some young males may have a fleck or two of red on their throat.

Two other species are sometimes seen here – the Rufous Hummingbird and the Black-chinned Hummingbird. Juveniles and females of these species are a little hard to distinguish from Ruby-throated females and youngsters, but the males are distinctive. Rufous males are a bright bronze color, with an orangey red throat. Black-chinned males are green with a black throat, below which, in the right light, a brilliant violet band will flash.

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Farther west, in the Big Bend area and west into New Mexico, Arizona, and California, hummingbird diversity is much higher. About 15 or so species are known from the USA, and most of these occur in the western states. For the apex of hummingbird diversity, head to the highlands of South America (e.g., Colombia, with about 140 species), where dozens of different species can be seen, some of them truly spectacular. Most of these are residents in the tropics and do not migrate.

 

Male and Female Ruby-Throated Hummingbirds, slow motion, August 2010 from Hummer Lover on Vimeo.

All hummingbirds behave similarly. Masters of speedy, controlled flight, they can hover in place, move backwards and forwards, dive and soar with incredible speed and precision. They can reach speeds of up to 60 mph, their wings whirring at 80 beats per second. Males in particular are territorial and aggressive, cheeping furiously as they drive off rivals from a good food source.

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Ruby-throated Hummingbird. Photo by JC Donaho http://jcdonaho.com/

Hummingbirds’ main food is flower nectar, so they are important pollinators of certain species of plants. They especially seem to gravitate to red flowers, although other colors are visited. Their long thin beaks and even longer tongues allow them to reach inside floral tubes that are much too deep for most butterflies and bees. Since birds in general have a poorly developed sense of smell, flowers pollinated by hummingbirds typically have no scent.

Hummingbirds also eat small insects such as fruit flies and gnats, catching them on the wing or finding them inside the flowers they probe for nectar.

Bottle feeder with ant-guard

Bottle feeder with ant-guard

Because they love sweet fluids, it is easy to provide feeders for hummingbirds, and several designs are available. Hummingbird food is simple to make; you just need sugar and clean water. DO NOT use any other sweetener – including honey or other types of sugar –just your standard white table sugar. Use four parts water to one part sugar. Bring the water to a rolling boil, add in sugar and stir until it dissolves, then turn off the heat. Do not cook it too long or it will start to caramelize. Let the solution cool and you are ready to fill your feeders. Keep extra sugar solution in the refrigerator.

IMPORTANT! If you want to feed hummingbirds you must commit to regularly changing their sugar water food! Sugar water ferments and/or grows mold quickly, and when spoiled it can make hummingbirds sick. Since you will need to clean the feeders about every three days, do not fill them too full or you will waste a lot of sugar solution. Fill them from between ¼ to ½ full, at least until you see how fast the hummers empty them.

DO NOT add red food coloring, and avoid commercial solutions with food coloring. Coloring is not necessary, as most feeders have red parts built in to attract the hummers’ attention. Like spoiled sugar water, food coloring is bad for the hummingbirds’ health.

Every three days, even if your feeders are not empty, clean them thoroughly with hot water and refill them with fresh solution. At the end of the season you should sterilize the feeders either in the dishwasher or using a dilute bleach solution before drying and storing them until next year. I prefer to use glass feeders as these are easier to sterilize.

 

Perky Pet feeder

Perky Pet feeder

A few guidelines on feeder placement – hummingbirds are not at all shy, so you can put feeders near your house where you can enjoy watching their activity. I put one right outside my kitchen window, and hang others around my back yard, especially near trees or bushes where hummingbirds can perch between bouts at the feeder. If you put out more than one feeder (I recommend this!), don’t put them too close, and ideally place them out of sight of each other to avoid their being monopolized by one dominant male.

Salvia leucantha, aka Mexican Sage

Salvia leucantha, aka Mexican Sage

In a good season, you will have dozens of hummingbirds – and the more feeders, the more hummingbirds! I usually put out from 3 to 9 feeders, depending on activity. Of course, hummingbirds also visit flowers for nectar. The classic hummingbird flower is red with a long floral tube, but many others also bring them in. Some good choices are salvias (many varieties), hummingbird bush, coral vine, trumpet creeper, and russelia.

Salvia guaranitica, or Purple Majesty Sage

Salvia guaranitica, or Purple Majesty Sage

Of course, if you have outdoor cats, you should not put out hummingbird feeders or any other kind of bird feeder!

Did you know?

  • Hummingbirds are only found in the Western Hemisphere.
  • Hummingbirds’ jewel-like, glittering colors do not come from pigments, but result from the refraction of light hitting special structures on their feathers.
  • The Bee Hummingbird from Cuba, less than 2.5 inches long, is the world’s smallest bird.
  • The largest hummingbird is the Giant Hummingbird, from Patagonia, Chile. It is about the size of a cardinal, but only weighs half as much (about .65 ounces, or about 1/20th of a pound).
  • The longest hummingbird is the Black-tailed Trainbearer from Colombia. The male’s total length is about 10 inches, including its 6.5 inch tail!
  • The Sword-billed Hummingbird from Ecuador has a 4 inch long beak, almost as long as its body!
  • Check out the PBS Nature special on hummingbirds, “Magic in the Air,” for some amazing footage of these incredible creatures!

Finding the flora and fauna: Butterfly Center staff conduct a BioBlitz in Memorial Park

Published by on in Plants & Insects
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Editor’s Note: The term “BioBlitz” was first coined in 1996 for intense attempts to record all the flora and fauna within a designated area. National Geographic, which has partnered with parks around the country for various BioBlitzes, describes them as “a 24-hour event in which teams of volunteer scientists, families, students, teachers, and other community members work together to find and identify as many species of plants, animals, microbes, fungi, and other organisms as possible within a designated area.”  These quick and dirty surveys are used both to gather information about the biodiversity of a given area, and since members of the public and other non-experts (students, etc.) are often included as participants, as ways of sparking public interest in local flora and fauna.

The “Eco-Tech” panel of the Memorial Park Conservancy recently recruited the Butterfly Center to conduct a preliminary survey or “mini-BioBlitz” of the insect fauna throughout Memorial Park, with the idea of inviting members of the public to help on future surveys. One of the goals of the panel is to get some baseline data on the biodiversity of all the creatures that live in Memorial Park, and from there, make plans on how best to preserve and manage or enhance this wildlife.

We were asked to survey several different natural habitats in Memorial Park (i.e., not the golf course). On a sunny morning in early July, Butterfly Center staff members, our summer intern, and a couple of volunteers drove out to Memorial Park armed with insect nets and containers.  While some surveys (such as birds or trees) can be done without collecting, there are so many kinds of insects (and so few experts) that at least some specimens have to be collected in order to make identifications.  

We decided to sample 10 transects — 100 feet long by about 8 feet wide — each one in a different area. Our first couple of sites were in open prairie vegetation, so we used sweep nets and aerial nets to collect samples. In case you are not versed in insect collection techniques, a “sweep net” is a canvas net bag on a sturdy metal frame that is swished through the vegetation. Periodically, the contents are emptied into Ziploc bags or other containers. 

This giant fishing or nursery web spider was nearly three inches across! (photo by Zac Stayton)

This giant fishing or nursery web spider was nearly three inches across! (Photo by Zac Stayton)

 

Picture 1137

We found lots of these small millipedes (and a few slugs) in the leaf litter in the forested areas. (Photo by Zac Stayton)

Aerial nets are the more familiar “butterfly nets”: a much lighter, more delicate net bag that is swung through the air (it should NOT be dragged on the ground, used in water, or swiped through bushes!). These nets are more for catching fairly large, individual insects, especially ones that fly, so samples are put directly into a glassine envelope, or vial, or other appropriate container (or, if it is something readily identifiable, simply noted and released). Sweep nets generally collect things like grasshoppers and katydids, walkingsticks, mantids, leaf hoppers, stink bugs, the odd caterpillar, spiders, etc. Aerial nets are useful for larger flying insects such as butterflies, dragonflies and damselflies, wasps, bees, some beetles, certain flies, etc. 

In the more forested areas, sweep nets were not really appropriate, so we used the aerial nets and also took litter samples (scraping up leaf litter and bagging it). Litter samples are typically brought back to the lab to process in a so-called Berlese funnel. Many small arthropods who live in the litter of the forest floor, including springtails and cockroaches, ants, small beetles, millipedes, etc., can be collected in this way.

Another find in the leaf litter: a “woolly bear” caterpillar. This is the larval form of the Giant Leopard moth, Ecpantheria scribonia. The caterpillar rolls up in a ball, showing red stripes between segments covered with black “fur” (these caterpillars do not sting but probably taste bad so are warningly colored). (photo by Nancy Greig)


A find in the leaf litter: a “woolly bear” caterpillar. This is the larval form of the giant leopard moth, Ecpantheria scribonia. The caterpillar rolls up in a ball, showing red stripes between segments covered with black “fur” (these caterpillars do not sting but probably taste bad so are warningly colored). (Photo by Nancy Greig)

There are many other collection techniques, none of which we used in this preliminary survey. Pitfall traps are always fun; they are empty cans or jars set into the ground with their mouths at ground level. Sometimes bait (a little raw chicken or fish, for example) is put in the bottom.

Crawling insects, especially those interested in odorous food, fall into the “pits” and cannot get out. Such traps need to be checked every couple of days — often they will contain different kinds of beetle, maybe a cockroach or two, etc.

Malaise traps are screen tents or baffles that trap small flying insects. The insects get caught in the folds of the screen and since they typically crawl upwards to escape, can be funneled into a container filled with alcohol.

Yellow pans are any wide, shallow container with a yellow (painted or otherwise) bottom.  These are partly filled with water and a bit of liquid detergent. Wasps and pollinating flies, etc., are attracted to the yellow color and cannot escape once they fall into the soapy water. Yellow pans need to be used in open areas in sunny weather and the samples removed every day or two.

Our final survey site was along the banks of Buffalo Bayou, which was much higher than usual so there was not much shore. Here, we mostly used aerial nets. We saw several things in this area that were not seen other places, especially tiger beetles, damselflies, etc. Here, we mostly used aerial nets (or grabbed things with our hands). 

The gorgeous Ebony Jewelwing a common damselfly species along the banks of Buffalo Bayou in Memorial Park

The gorgeous Ebony Jewelwing, a common damselfly species along the banks of Buffalo Bayou in Memorial Park.

 

The vibrantly colored Vivid Dancer is a common damselfly species along the banks of Buffalo Bayou in Memorial Park

The vibrantly colored Vivid Dancer is a common damselfly species along the banks of Buffalo Bayou in Memorial Park.

By noon, it was blazing hot and we were all soaked in sweat, so we bagged things up and stopped at the Shandy Café (great little place on Memorial Drive) for lunch on our way back to the Museum. 

Although we only collected for about three hours, we have our hands full in identifying everything. We first have to sort things to order, identify what we can, and then we will probably have to send some things off to experts in the various insect groups. I’m sure it will take us several weeks! 

Some of the coolest things we found: 

It’s always fun to open up the sweep net and find walkingsticks or praying mantids, or a colorful leafhopper. We picked up quite a few different grasshoppers and a few katydids.  We noted but did not catch too many butterflies (we can identify most of these by sight, so no need to collect).

I like wasps and bees; we saw several of the large red Polistes wasps, carpenter bees, leaf cutter bees, and a really cool “digger” bee starting her nest tunnel in the sand (see attached video clip). A medium-sized beetle that looked like a wasp was visiting flowers in several places. 

The very fast tiger beetles mostly eluded us down at the bayou’s edge, but we did catch a few damselflies there. The most common one there was the lovely Ebony Jewelwing.

Tiger beetles are extremely fast moving, long legged, predatory beetles that often occur in open sandy areas, especially along streams. We saw many of these, probably Megacephala virginica – and managed to catch a few – along the bayou. (photo from BugGuide.net by Chris Wirth)

Tiger beetles are extremely fast moving, long-legged, predatory beetles that often occur in open sandy areas, especially along streams. We saw many of these, probably Megacephala virginica – and managed to catch a few – along the bayou. (Photo from BugGuide.net by Chris Wirth)

 

Hibiscus bee, Ptilothrix bombiformis

Click here to watch a video of a female Hibiscus bee, Ptilothrix bombiformis, a solitary species as she digs a nesting tunnel into hard-packed earth as we found on our BioBlitz.

Once we have compiled our results and reported them to the EcoTech Panel, they will then make plans for another survey sometime in the fall. I believe they intend to invite more general participation, so if you are interested in the insects of our area, keep your ears open!

Help us thank the birds and bees (and bats, moths and flies!) during National Pollinator Week

Published by on in Education
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For the next several paragraphs, we’ll be talking about a few very special flying creatures (and some others) that are called pollinators — to whom we owe huge thanks for providing much of the food we eat! 

Without these pollinators to carry their pollen from flower to flower, plants could not form fruits or seeds to reproduce themselves and feed our whole ecosystem of hungry animals — including humans. Did you know that at least one of every three bites you take is thanks to a pollinator? (More if you are vegetarian.)

Although the world’s pollinators include many of the animals you’d expect and more (e.g., also butterflies, beetles, monkeys, even some rodents and lizards), the most important pollinators of our fruit and vegetable crops are insects, particularly bees. Unfortunately, today many pollinators are in danger due to habitat loss, overuse of insecticides, and other factors. To learn more about the threats facing pollinators and what you can do to help, visit the Pollinator Partnership’s webpage at pollinator.org.

National Pollinator Week, June 16-23 this year, was initiated by a group of biologists calling themselves the “Pollinator Partnership,” whose goal was to bring the public’s attention to the vital ecosystem services provided by pollinating bees, butterflies and moths, beetles, birds, and bats — and to make people aware of the urgent issue of their declining populations. 

Seven years ago, the U.S. Senate voted unanimously to designate a week each June to commemorate the importance of pollinators. Pollinator Week has now grown to be an international celebration.

From feasting to beekeeping, learn more about the efforts of these hardworking — and essential — animals in three special events planned for National Pollinator Week. 

Behind-the-Scenes Tour of the Cockrell Butterfly Center
Tuesday, June 17, 6 p.m.

In addition to the Butterfly Center and Insect Zoo, you will visit the containment room and rooftop greenhouses — areas not open to the public where staff cares for the Museum’s butterflies and other insects. Kids 5 and above welcome! Click here for ticket info.

Beekeeping Class
Wednesday, June 18, 6 p.m.

From the tools and techniques needed to start your own apiary to tips of daily life with bees, beekeeper Shelley Rice will share the basics of starting your own beehive and how to harvest wax and honey naturally and safely. Participants will meet at Shelley’s private apiary. Advance registration required. Click here for ticket info.

Cultural Feast: A Culinary Cultivation — All About the Birds and the Bees
Sunday, June 22, 6 p.m.

In the perfect kick off to summer, join the staff of the Cockrell Butterfly Center at Haven for a five-course meal showcasing the contributions of bees and other pollinators to our food sources prepared by chef Randy Evans. Culinary historian Merrianne Timko will discuss the culinary history of these pollinator-focused ingredients. Advance reservations required by June 16. Click here for more information and to purchase tickets online.