STEM & GEMS: Insects and plants fascinate “bug nerd” Lauren Williamson

lauren photo in CBCEditor’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 Lauren Williamson, Entomologist in the Cockrell Butterfly Center

HMNS: How old were you when you first became interested in science?
Williamson: Ever since I can remember! I was always catching bugs, playing with animals, and looking at flowers, plants, etc.

HMNS: Was there a specific person or event that inspired you when you were younger?
Williamson: I had a biology teacher in junior high that told me about entomology and told me that I should look into that field for a career since I had such an interest in insects.

HMNS: What was your favorite science project when you were in school?
Williamson: An insect collection, of course!

HMNS: What is your current job? How does this relate to science, technology, engineering, or math?
Williamson: My title is “entomologist”, aka “bug nerd.” My job revolves around importing exotic butterflies to display in our Butterfly Center. Not only do I need to know a lot about insects, but I also need to know about government regulations, computer applications, and accounting. We also do a lot of outreach programs, so it’s a necessity to be comfortable presenting to large groups.

To get a degree in entomology you have to take extensive coursework in biology, chemistry, physiology, and math.

HMNS: What’s the best part of your job?
Williamson: I play with butterflies all day — need I say more? Not to say that my job doesn’t involve a lot of hard work, because it does, but the fun parts of my job make it all worth it!

HMNS: What do you like to do in your spare time?
Williamson: I love to play with my animals (three dogs: Merle, Hank, and Molly; and a bird: Carlos), go on insect collecting trips, camping, crafts, going to museums and seeing movies with my husband.

HMNS: What advice would you give to girls interested in pursuing a STEM career?
Williamson:
Make sure you study, study, study! Ask a lot of questions and learn all of the material as much as possible. Every year adds more information to the knowledge base you already have, so it only gets harder.

HMNS: Why do you think it’s important for girls to have access to an event like GEMS?
Williamson: This is a great way to experience some of the wonderful career paths you can take with a firm knowledge of science, engineering, technology, and math. These subjects are the foundation of our everyday lives, whether you realize it or not! There will always be a demand for employees in these ever-growing and changing fields so it is important to get in an interest in them as soon as possible.

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It’s a boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly Center

Editor’s Note: Today’s blog comes to us from Cockrell Butterfly Center Butterfly Rearing Coordinator Celeste Poorte.

The Cockrell Butterfly Center has had the privilege of witnessing a rare natural phenomenon recently. On July 10, a very unusual butterfly emerged from its chrysalis in the Museum’s greenhouses used for breeding and raising butterflies. This butterfly has a bilateral division: one side is female, while the other is male.

This condition is known as gynandromorphy. The term derives from the Greek “gyne” (female) and “andro” (male). This extraordinary butterfly is of the species known as the Great Southern White (Ascia monuste).

The Great Southern White is a cream-colored butterfly in the Pieridae family and occurs in the Southeastern United States and Central and South America. This species is sexually dimorphic, meaning the male is physically distinguishable from the female. In the case of the Great Southern White, the female has darker, greyer wings than her lighter male counterpart.

Our unique specimen’s right wing is ivory with dark scallop designs on the edges. Its left wing is a solid warm grey tone. On the right side of the abdomen you can see an anatomical protrusion not observed on the left side. This is a single clasper, a structure usually found in pairs on male individuals. Claspers are used by males to grip onto the female during mating. Our particular butterfly only has one clasper, on the same side of the body showing the male coloration and wing pattern. These observable features suggest that the entire right side of the butterfly is genetically male, while its left side is female. NEAT!

It’s a Boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly CenterGynandromorphy is the result of a genetic mutation. It is an extremely rare condition and a topic of interest to researchers. As early as the 1700s, scientists have recorded cases of organisms that seem to be half male and half female. Recognized cases of gynandromorphy typically occur in species with sexually determined phenotypes. In the butterfly world, these specimens are prized by collectors. Cases most commonly occur in insects. Examples have also been documented in crustaceans (especially lobsters) and even birds. (Gynandromorphy has not been observed in mammals.)

It’s a Boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly CenterCrustaceans, especially lobsters (Homarus americanus), can also display gynandromorphy. (original photo by A. R. Palmer; taken at the Bonne Bay Marine Station,)

It’s a Boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly Center

How does this bizarre genetic anomaly occur? All sexually reproducing organisms begin as a single cell (a zygote) from the fusion of two gametes, a sperm and an egg. This single cell then undergoes division after division to produce all the cells in the body. In insects, each cell division — from the zygote on  — is determinate, meaning that cell’s fate is set. The earliest divisions will determine left from right, front from back, and top from bottom. Therefore, gynandromorphy is the result of an error during one of the very first cell divisions.

In Lepidoptera (butterflies and moths), sex is determined by a WZ/ZZ (female/male) system. We are more familiar with the human sex chromosomes X and Y, where females are XX and males are XY. In butterflies, this situation is reversed, and it is the female who has the heterogametic sex chromosomes. It is important to note that what is important in determining sex is the number of Z’s. Any individual with only one Z will be female (even if it is missing a W), and any individual with two (or more) Z’s will be male.

When cells divide (mitotically), identical copies of DNA are passed on to the resulting daughter cells. Occasionally a non-disjunction event occurs, in which the duplicated chromosomes do not correctly separate from one another, leaving one daughter cell missing chromosomes, while the other has extra copies. Gynandromorphy can happen when a non-disjunction occurs in a Z chromosome of a ZZ individual (male). In this situation, when the duplicated Z chromosomes fail to separate correctly, one daughter cell ends up with a single Z (female) and the other ends up with three Z’s (male). All the progeny of the female cell will be female, and the progeny of the male cell will be male. As a consequence, one side of the individual will have male traits, while the other side will have female traits. This is called a bilateral gynandromorph. If the non-disjunction of the Z chromosomes occurs at a later division, the butterfly will have a smaller section that is one sex while the rest of it is the opposite sex. Additionally the non-disjunction can occur several times during development resulting in a patchwork effect, yielding what is known as a mosaic.

Non–disjunction is not the only way this condition can arise. Other genetic events resulting in the spontaneous anomalous loss of a Z chromosome in a cell within the first few divisions will have similar effects.

It’s a Boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly Center

It’s a Boy! And a girl? Butterfly with rare condition emerges in Cockrell Butterfly Center

So there you have it, gynandromorphy is a bizarre but often strikingly beautiful genetic error. The Cockrell Butterfly Center is lucky to have raised a butterfly with such a rare condition so we can all learn about the peculiarities of the natural world!

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.

This semi-annual sale’s not about skivvies, it’s all about Skippers (and Painted Ladies, Nymphalids + more): The Semi-Annual Plant Sale!

I think we can all agree that butterflies are awesome. They are familiar and beautiful, but there are also some little guys out there that hardly ever get a second glance. I’m talking about hairstreaks, smaller nymphalids, skippers and the like. From far away, these butterflies may not seem like much, but up close they are just as pretty as a giant swallowtail.

Hairstreaks

Let’s start off with one of my all time favorites: the hairstreaks. These members of the Lycaenid, or “gossamer winged,” family get their name from the thin, hair-like lines that cross the under surfaces of their wings. Many of the hairstreaks have slender “tails” on their hindwings, which resemble antennae on the wrong part of the body! While resting they will rub their hindwings together, causing their “tails” to wiggle. Coupled with colored eyespots, this makes their back-end look just like a false head. This illusion comes in handy with predators, attracting them to the wrong end of the body, allowing the butterfly a quick escape in the opposite direction.

Semi-Annual Plant Sale | Oct. 6, 2012Hair Streak

The hairstreaks are fast butterflies with erratic flight patterns. They can also be hard to view because of their size — from ½ inch to only about 1 ¾ inch in wingspan — so it can be hard to identify different ones in the field. If you do come across a hairstreak, however, try to get a good look — they’re worth it! Some species of hairstreaks have only one brood per year in the spring, while others have several from spring through fall.

You generally can’t attract hairstreaks to your garden with host plants. They eat a wide variety of larval foods, depending on the species — some are dried up leaves, mistletoe (try planting that one!), hackberry, oaks, cedar, pine and a variety of legumes. The best way to attract hairstreaks to your garden is by planting the nectar plants that they like. Some good ones are almond verbena, lantana, asters, frog fruit — anything with really small, tubular shaped flowers arranged in clusters.

Nymphalids

Nymphalids, or “brush-footed” butterflies, are also some of my favorites. This family of butterflies takes its name from their highly reduced front legs, which are covered in tiny hairs and resemble brushes. At first glance, it appears these butterflies have only four legs. This family is very diverse in size and shape, without many recognizable characteristics in common. As adults, however, many do not visit flowers for nectar, but rather feed on tree sap, rotting fruit, dung and carrion. These guys know how to survive a drought!

Semi-Annual Plant Sale | Oct. 6, 2012Texas Crescent

You may see some of these butterflies flying about on warm winter days. Some species overwinter as larvae and/or adults; however, they won’t breed until host plants become available in the spring.

Some of my favorite “brushfoot” butterflies in Houston are the Texan Crescent, the Question Mark and the American Painted Lady.

The Texan Crescent (Anthanassa texana) is tiny — up to 1 ¾ inches in wingspan. They are around for much of the year, spring through fall. Their host plants include members of the Acanthus family: flame acanthus, ruellia, dicliptera, shrimp plant. When you get caterpillars, you will have lots, so expect your “fruit cocktail” shrimp plant to be stripped!

Question marks (Polygonia interrogationis) are gorgeous! If Stevie Nicks were a butterfly, she would be this one, with its dark purple, velvety, gypsy-like wings. I have seen question marks in the country covering the sides of dirt roads, absorbing minerals. Their larvae feed on the leaves of elm and hackberry trees, and sometimes nettles. These butterflies are out during most of the year, hibernating during the winter and estivating (becoming dormant) during the summer. One sat for days on my outdoor ceiling fan this summer. They are on the larger side, size-wise — up to 3 inches across.

Semi-Annual Plant Sale | Oct. 6, 2012Question Mark

American Painted Lady (Vanessa virginiensis) butterflies are about 2 inches wide and are abundant in spring and fall. Their favorite host plants are in the Aster family. I learned that the larvae of this butterfly feed on the curry plant — which we will have at the fall sale!

Skippers

Skippers are cute little creatures that have been classified as an “intermediate” between butterflies and moths. However, most lepidopterists agree that they are more closely related to butterflies. Skippers have stout, hairy bodies with large heads. Their antennae are spaced far apart, more on the sides of their head, with a curled hook at the end instead of the usual clubbed antennae seen in “typical” butterflies. Their wingspan usually measures less than one inch, except for the long-tailed skippers, which may be over 2 inches across.

Semi-Annual Plant Sale | Oct. 6, 2012Fiery Skipper

Depending on the species, in the larval stage, skippers eat mostly oaks, mallows, legumes and grasses. You may have some of these in your lawn or garden right now!

Skippers often drink nectar from low growing flowers. I have seen them many times on trailing lantana by the Museum greenhouses. They also like to imbibe nutrients and salts from shallow mud puddles.

Their flight is fast, whirling and erratic, so the best way to observe them is while they are perched on a flower sipping nectar.

The HMNS Semi-Annual Plant Sale

When: Saturday, October 6th from 9 a.m. to noon
Where: On the 7th level of the museum parking garage
How Much: FREE

We’ll have all the necessities: milkweed, pipe-vine, passion-vine, porterweeds, lantana, pentas, and more. We will also have a lot of the favorite plants of those “lesser known” butterflies that I’m sure you will now be looking for this fall!

If you plan on coming to the sale, please come early to get the best selection. To make life easier on yourself, please bring your own wagon.

See you Saturday!