SUBROSA
Number 38    September - October 2004
                 

THE BIRDS AND THE BEES
AND, LET US NOT FORGET THE BUTTERFLIES,
OF THE SHAKESPEARE GARDEN

By Martha Burkard and Bea Whyld

A visit to The Huntington Shakespeare Garden always brings about a feeling of amazement at the transformation there in recent years, especially in the springtime when so many creatures that inhabit this exquisite setting are going about their business.

We have chosen to research three of these and share their life habits with you: the hummingbird, the honeybee, and the monarch butterfly.

 

THE HUMMINGBIRD (Calypte anna)

 

The one bird that seems to attract the most attention is the hummingbird. It takes a quick eye to catch and identify one of these marvelous creatures.

Here in southern California we are extremely lucky with respect to hummingbirds. The hummer is basically a migratory creature except for the Anna who stays right here all year, although it may occasionally vacation in Southern Arizona. If you spot a hummingbird in the Shakespeare Garden that is 3 1/2” to 4” long, whose whole head and gorget is a brilliant rose – red (except for a white spot behind the eye), and whose back is green and under parts grayish, you have just had contact with a male Anna. The female’s gray and green parts are darker than the male and she has only a splash of red on her throat.

Anna is the largest hummer in California and the only one that sings with a squeaky warbling song from a perch and a chattering “chick” note while feeding.

Some facts that are common among hummingbirds:

They are found only in North and South America.
Most flap their wings about 50 or so times a second, explaining why we only see them as a blur.
They can fly right, left, up, down, backwards, upside down and at speeds of up to 60 mph.
Even though they can fly this fast, they can suddenly stop and make a soft landing.
Other birds get their flight power from the down-stroke only. Hummingbirds have strength on the up-stroke, as well.
Their tiny feet are almost useless except for perching. If a hummer wants to travel 2”, it must fly.
Hummers lift from perches without pushing off; they rise entirely on their own power, flapping their wings at almost full speed before lifting off.
The wing is flexible at the shoulder, but inflexible at the wrist.
Hummers feed every 10 minutes or so all day.
They consume 2/3 of their body weight in a single day.
A major part of their diet is sugar which they get from flower nectar and tree sap. Since they need protein in order to build muscles, they also eat insects and pollen.
The tongue of the hummingbird has grooves on the side, which are used to catch insects in the air and also from leaves and spider webs.
Their bills are perfectly suited for probing into the center of flowers for the nectar. As they feed, hummers accidentally collect pollen and as they move from flower to flower, help the flowers to reproduce.
Male and female hummingbirds establish separate territories—she to build a nest and feed her young, he to protect a reliable food source. The male takes no interest in nests or the care and feeding of babies.
The hummingbird that does not fall prey to accident or attack can live 10 years.

 

THE HONEYBEE (Apis mellifera)

Next let us look at the honeybees that have become constant visitors to our lovely garden.

Honeybees probably originated in tropical Africa and spread to northern Europe and east into India and China. They were brought to our shores by the first colonists and are now found worldwide. A typical hive contains approximately 20,000 bees that are divided into three types: queen, drone, and worker. Let us first examine the lifestyle of the queen.

The queen is either female or bisexual and the largest of the inhabitants in the hive. Her lifespan, depending on the number of her sperm, can be 2 years. Her primary responsibilities are to kill her sisters and her mother, lay 1,500 eggs per day or 200,000 per year and to secrete a pheromone, (a chemical secreted by an animal that influences the behavior or development of others of the same species) keeping the workers uninterested in reproduction on their own. The rate at which she lays eggs leaves her no time to eat or fly around. A group of 5 to 10 workers feed her a small bit after she lays about 20 eggs.

The queen controls the sex of her offspring. When an egg passes from her ovary to her oviduct, the queen determines whether the egg is fertilized with sperm from the spermatheca. A fertilized egg develops into a female honeybee, either worker or queen, and an unfertilized egg becomes a male honeybee, a drone.

When the queen stops making pheromone or laying eggs, one of her most recent eggs will be moved to a specially prepared queen cell to produce a replacement queen. When this occurs, the newly hatched queen destroys any other unhatched queens, fights to the death any hatched queens, destroys her mother, and then takes her mating flight. In this flight, the virgin queen flies to a congregation area where hundreds or thousands of unrelated drones await. The drones pursue the queen and several mate with her in flight. These sperm will be used, a few at a time, during her life to fertilize her eggs.

The drone, whose primary responsibility is to mate with the queen, is a medium size bee, who lives 21-32 days in the spring, 90 days in summer or until mating, 0 days in winter. The drone’s role is probably the least attractive. The drone is tolerated in the hive only when there is a possibility he may mate with the queen. They lack the body parts to effectively harvest nectar or pollen to feed themselves. They also lack a stinger of any kind. They are designed for mating only.

Those we see in the garden are the workers. Well, who else would you expect to find in a garden, especially in those hours when we are not open to our visitors, except workers! The worker is the smallest of the bees in the hive and has a lifespan of 20-40 days in the summer and 140 days in the winter. This unimposing little creature, a sterile female, has a wealth of job assignments:

Make the comb
Tend larvae
Tend young drones
Clean the hive
Gather nectar
Gather pollen
Gather propolis (A substance that provides protection against harmful bacteria, viruses and fungi—a plant resin collected by the bees for use in and around the hive and used for its healing properties by the ancient Egyptians, Greeks and Romans. It is currently being rediscovered for its medicinal benefits.)
Evaporate nectar
Cap cells
Defend hive
Starve drones


Quite an imposing list for such a short life span!

Of the above list, the importance of the gathering of pollen cannot be stressed too much. All fruit and seed crops must be pollinated. Bees must pollinate clover for animal forage, cotton for oil and fiber, and sunflowers for oil. Most of our vegetables are really fruits—tomatoes, peppers, beans, peas, corn, squash, cucumbers--and most of these need pollination by bees. Pollination is critical not only to plant and bee life, but to our own human survival.

 

MONARCH BUTTERFLY OF NORTH AMERICA (Danaus plexippus)

 

The North American Monarch butterfly is part of a larger family, Lepidoptera, which is found around the world. What is most intriguing about the Lepidoptera family is its “metamorphosis”, to transform oneself from a caterpillar to a beautiful butterfly.

The Monarch butterflies that call North America home come from two distinct populations. The Rocky Mountain Range is the border, which separates the eastern and western Monarchs. Although Monarchs on both sides of the Rockies resemble one another in appearance and habits, it is assumed that little or no interbreeding has occurred between the two groups.

The Monarchs are also known as either being a summer or winter butterfly. Those born in early spring are the offspring of the wintering monarchs, which migrated from Canada the previous fall. The life span for the summer Monarchs is 6 to 8 weeks. During a season, it will take 4 to 5 generations of mating Monarchs to reach southern Canada.

Since the North American Monarchs are migratory, they can be seen during the summer crossing the continent from coast to coast, and from Mexico to southern Canada. The northern limits for all migrating Monarch butterflies are limited by the availability of the milkweed plant on which to lay eggs and provide food for the hatching caterpillars. Adult Monarchs rely on wildflowers for their nectar, “floral fuel” for energy during flight.

There are roughly 2,400 species in the milkweed family Asclepiadaceane, and about 100 species in the genus Asclepias found in North America. Various species of milkweed have different colored blooms and some are scented. The common milkweed, Asclepias syriaca, is the most important for the Monarch butterfly.

In late fall, as colder temperatures and shorter days set in, the summering monarchs must begin their migration south to their coastal roosting sites along the California coast. This group of migrating monarchs will return to the same wintering site as their ancestors. Monarchs may fly up to 80 miles a day and will travel over 1,000 miles to reach their winter roost.

By November, the Monarchs, having survived the long hard journey south, are now clustered together, high atop pines and/or eucalyptus trees. When the days are warm and sunny, they will leave their roosting site to look for water and to feed on the sweet nectar of flowers. The life span for the winter Monarchs is 6 to 8 months.

In late February, as the weather turns warm, the wintering Monarchs begin to mate. Both males and females will mate with several partners. The female Monarchs will carry sperm sacs from several males. The handsome male Monarch can be identified by the two black spots on its hind wings. The spots are scent pouches that store sex pheromones used to attract the female.

Once the female Monarchs have mated, their time is spent searching for clumps of young, healthy milkweed plants on which to lay their eggs. They will avoid milkweed plants already taken by other Monarch mothers, since earlier hatching larvae may eat the newly laid egg as a food source.

Female Monarchs have smell receptors on their antennae, and taste sensors on their feet. These Monarchs will use the smell receptors to find the milkweed plants. Once they have selected the milkweed plant, they use the taste sensors before touching the leaf.

To conceal their eggs, female Monarchs lay their eggs on the undersurface of a leaf base. Using the two claw-like toes on the tip of their feet, they grasp the edges of the leaf, and with their body in position they will lay a single egg. A female Monarch will lay approximately 500 eggs during a three to four week period, only taking time out to feed and to drink water. The reason for laying large numbers of eggs is to insure that at least some of the eggs will survive and continue the life cycle of the Monarch butterfly. The butterflies will die soon after completing their respective functions.

The egg itself has a hard outer shell to protect the new developing larva. This hard shell is formed while inside the female Monarch. At the top of the egg is a marked depression, with a funnel-shaped opening, through which air and moisture passes. The opening allows the sperm to enter during fertilization. The shell is lined with a layer of wax to prevent the egg from drying out.

Once the egg is fertilized it will take five days before the larvae hatches. As the larva emerges from its eggshell, it is only 2 millimeters in length (0.08”). It is so small it could drown in a raindrop! The newborn larva is a “juvenile feeding machine” eating day and night, munching on the milkweed plant’s fine leaf hairs, before attacking the more substantial material of the leaf blade. Milkweed is the only food the larva/caterpillar will eat. A chemical compound found in the milkweed plant gives the larva an unpleasant taste. This protective chemical prevents other insects and animals from eating the newly developing caterpillar. At the end of two weeks the full-grown caterpillar will have increased its weight approximately 2,700 times. Compare this to a human baby growing to the size of a gray whale in two weeks!

About 3 weeks after hatching from its egg, and having shed its skin four times during this period, the full-grown caterpillar will have its last meal. The caterpillar must now find a well-protected and secure place for its next phase of life as a pupa. Like all caterpillars, the Monarch larva has a silk-making gland in its lower lip, which produces a liquid silk. This silk is spun into a round button of fibers which the caterpillar secures itself to by wriggling its rear-end back and forth, using its (anal) claspers/hook to grasp the button. With its head facing down, the body of the caterpillar is curved to form like the letter J. It will remain in this position during its metamorphosis. Inside its last larval skin, hormones begin the cellular transformation of the pupa. The first outward signs that something is changing are the fading of the yellow color bands of the caterpillar, to a dull translucent blue green. Once the pupating caterpillar sheds its skin for the last time it forms a cuticle (covering) that will encase the developing pupa. When the cuticle hardens, it will turn green and is now called a chrysalis. It is within the chrysalis that metamorphosis takes place.

Many people believe the caterpillar inside the chrysalis is part caterpillar and part butterfly before merging into a beautiful Monarch butterfly. In fact, the caterpillar has actually been changed into a liquid mass. It will take about a week for the cells to fully develop and the newly formed Monarch butterfly emerge from the chrysalis. The darkening of the green chrysalis signals that the butterfly is about to enter its next phase of life.

   

Within a day after the color change, the adult’s reddish orange wings are clearly visible through the thin pupa casing. Inside the chrysalis, the newly formed butterfly twitches and twists preparing for its debut. Upon emergence the new butterfly will cling to the remains of the chrysalis with its wings hanging down in a vertical position. It may remain in this position for the rest of the day and night. A bright, calm day, just before noon is the ideal conditions for its debut.

When the early morning sunlight warms the Monarch, it will open and close its wings a few times before fluttering off to explore its new surroundings. The next 2 to 3 days are spent feeding on sweet nectar and drinking water, building its strength so it may continue its journey and the future of the Monarch butterfly.

It is our hope these explanations of the life and breeding habits of three fascinating visitors to our Shakespeare Garden will add to your appreciation and enjoyment of the beauty of these flying marvels as you take a leisurely stroll along the pathways. The enchantment of the garden is greatly enhanced by their presence.

Martha Burkard, Rose/Shakespeare Gardens Docent and Chair of the Tuesday Rose Propagation Group
Bea Whyld, Rose/Shakespeare Gardens Docent and Subrosa Editor

Photos in this article are from The World of the Monarch Butterfly by Eric S. Grace, published by Sierra Club Books.

 

Previous Article | Back to Contents | Next Article