by Janet Spencer

Eggs come in many different shapes, sizes, and forms. Come along as we learn about eggs!

BUG EGGS

One type of mosquito evolved in conjunction with the pitcher plant. The mother mosquito lays her eggs in the water of the pitcher plant. The larvae, which are impervious to the digestive enzymes exuded by the pitcher plant, hatch and grow, stealing nutrients from drowned bugs from the pitcher plant host.

• Stink bugs lay their eggs in the soil, and each egg is accompanied by a waterproof package of microbes which the newly hatched stink bug larva eats as soon as it hatches.   

• One type of Japanese beetle lays a clutch of eggs, and the mother beetle guards them until they are ready to hatch. When the hatching begins, she coats the eggs with microbe-laden mucus which is their first meal.

• Dung beetles carve out a round ball of dung and roll it around where ever they go. The female will lay a single egg inside a dung ball, and then, depending on environmental conditions, will either roll the ball into the sun to stay warm, or bury it in the dirt to stay cool so the egg has proper temperatures to develop.

The casuarina tree is a type of evergreen shrub. A female walking stick lays eggs that happen to look identical to casuarina seeds, dropping them randomly underneath the casuarina tree where she lives. Ants come along and collect her eggs along with the casuarina seeds, carrying them back to their storage unit. When the eggs hatch, the baby walking stick looks exactly like a newly hatched ant. The walking stick simply walks out of the ant nest and climbs the nearest casuarina tree to start the cycle all over again.

• When a female ladybug lays her eggs, she also lays a batch of unfertilized eggs. When the larvae hatch, they will eat the unfertilized eggs as their first meal.

AQUATIC CREATURES

One kind of brine shrimp lives in the brackish water of deserts. It lays two kinds of eggs: one kind with thin shells that hatch almost immediately, and another kind with hard shells that can withstand droughts of up to 15 years before hatching.

• The eggs of a whale shark are about a foot long and rectangular.    The eggs remain inside the mother’s body until they hatch, so they are born live. They grow into the world’s largest fish, up to 50 feet (15 m) long and weighing up to 15 tons.

• Female sunfish produce more eggs than any other known vertebrate, up to 300 million eggs at a time, making sunfish the single most proliferate vertebrate animal on the planet. Newly hatched sunfish measure less than a tenth of an inch (2.5 mm) long, and those that reach adulthood will increase their proportions by more than 60 million times their birth size, the most extreme size growth of any vertebrate animal.    A fully grown sunfish can weigh up to 4,400 lb (2,000 kg).

AQUATIC CREATURES

Colonies of jellyfish are either all male or all female. Both sexes release sperm and eggs.

• The eggs of the leopard frog are white on one side and black on the other.    The white part contains the genetic material; the black part contains a barrier to ultraviolet light.    When exposed to light, the egg rotates its black side up, blocking the UV radiation and absorbing heat that helps with incubation.

• A newly hatched crocodile is three times longer than the egg from which it emerged.

• The sex of alligator eggs is influenced by temperature.    If the eggs are incubated at a cooler temperature, all the young will be born female.    If the temperature is higher, males will hatch.    It is likely that climactic influences throughout the history of the planet caused various species to go extinct.

THE HUMAN EGG

The human egg is the largest single human cell. It’s about the size of a grain of sand and can be seen with the naked eye. It’s four times bigger than a skin cell and 26 times bigger than a red blood cell. By contrast, the sperm is the smallest cell in the human body.

• Contrary to popular belief, you were not created from the fastest sperm. Sperm cells completely surround the egg, with each one giving off tiny amounts of a chemical that helps weaken the protective barrier around the egg. When the barrier is sufficiently weakened, one sperm makes it through, thanks to the efforts of all of the others.

• Once released, a human egg only remains viable for 12 to 24 hours. However, if frozen cryogenically, a woman’s eggs can remain in suspended animation without damage for years.    The oldest frozen egg to produce a healthy baby had been frozen for 25 years.

CAVIAR: FISH EGGS

The word caviar originates from the Persian word “khaya” meaning “egg” which became the Turkish “havyar” before becoming the French “caviar.”

• To be considered true caviar, the eggs, also called roe, must come from the right species of fish and be processed in a particular way.

• There are 27 species of sturgeon, of which only around 10 to 12 different species are commercially fished or farmed for caviar.    The three main species used for harvesting caviar are Beluga sturgeon, Osetra sturgeon, and Sevruga sturgeon. Roe is also harvested from larger fish such as salmon, trout, paddlefish, bowfin and whitefish, but this is not “real” caviar because true caviar must come from the sturgeon family.

• The Beluga is the largest of the sturgeons. A single Beluga can produce around 38 to 45 pounds of roe. Smaller sturgeons, such as Osetra and Sevruga, yield about 3 to 5 pounds of roe. The beluga sturgeon can live up to 3 centuries, grow up to 24 feet long, and weigh over a ton. One of the reasons caviar is so expensive is because it takes so long for the sturgeon to reach egg-bearing age. The word “beluga” comes from the Russian word meaning “white.”

• Throughout the twentieth century the Caspian Sea was the major supplier of sturgeon roe for caviar. However, the Caspian suffered pollution, poaching, and over-fishing, all reducing sturgeon populations by up to 90% until the fish were on the brink of extinction.

• Today, most of the real caviar available for purchase is not only expensive but also required to be farm-raised due to the endangered status of sturgeon species.