BUGGED IN GREATER CINCINNATI

• 10 things we've learned • What's that funky smell?  • Invasion map (PDF) • Bugged photos • Incredible journey • Cicada Watch 2004

Now that most of the billions of cicadas are out of the ground and in various stages of dominance in Greater Cincinnati, here are 10 things we've learned:

1. Beware that tasty treat

It's still safe to eat the bugs, but children and women of childbearing age probably should limit their consumption because of mercury concentrations. Most cicadas have low levels of the neurotoxin, however, meaning people would have to eat hundreds of the bugs before there's any threat.

Tim Keener, a professor of civil and environmental engineering at the University of Cincinnati, helped test cicadas for mercury after media reports included cicada recipes. "It dawned on us: Anything that's been in the ground for 17 years has most likely been affected by its environment," he says.

Some people with shellfish allergies also have had allergic reactions after eating cicadas.

While it is safe for pets to eat cicadas, they may gorge themselves to the point of becoming sick. Choking also is a concern.

2. There are billions more than we thought

There are more cicadas in Greater Cincinnati than originally predicted. Researchers initially believed the region would see 5 billion of the 17-year periodical cicadas emerge from the ground. But early research indicates that there are many more - between 7 billion and 10 billion of the red-eyed insects, says Dr. Gene Kritsky, a cicada researcher and biology professor at the College of Mount St. Joseph in Delhi Township.

"In some areas of Delhi and Hyde Park, we are seeing up to 300 and 350 per square meter," Kritsky says. "That's three times more than expected."

3. Up to one-fourth die an early death

About 20 percent to 25 percent of cicadas are eaten by birds or squirrels (or squashed) before ever getting a chance to mate. "No one has ever studied that number," Kritsky says. "But we believe it to be a significant percentage."

4. Old Blue Eyes is for real

About 1/10th of 1 percent of cicadas emerging this year have blue eyes. They are unusual in another respect: They do not have the brilliant orange color associated with the wings of their red-eyed brothers. This implies some kind of genetic interference with the insect's red pigment. Although a relatively small percentage of cicadas has this discoloration, they number in the hundreds of thousands in this region.

There are no albino cicadas. The early nymphs turn color with the hardening of their exoskeletons, which are made of chitin. Few insects produce albinos.

5. Our ears really are ringing

The cicadas are drowning out the airplanes in Delhi Township. Decibel readings on Cincinnati's west side this week had cicadas singing to the tune of 91 decibels. For comparison, an overhead jet is between 70 and 80 decibels.

"There's some subjectivity on that because you can find a really loud tree, and then two blocks later they aren't as loud," Kritsky says.

6. There's a love song for everyone

Male cicadas have three distinctive calls. This is how females from the three cicada species can distinguish males of their own kind. Males of all three species also make a fourth sound, similar to a squawk, which researchers believe is either a warning call to alert others of predators or an attempt to intimidate predators. When males from all three species sing together, it's called chorusing.

Females of all three species click their wings together to let prospective mates know they are receptive.

7. They don't sleep

Cicadas quiet down at night - but not to sleep. Although cicadas sing to attract their mates, they still must see their partners for the mating to happen. The bugs have limited vision during daylight hours, but are completely blind at night. Since the bugs can't see each other in darkness, there's no reason to start singing.

"It's just not worth the hassle if they can't see the females flicking their wings," Kritsky says.

8. They played with the dinosaurs

References to cicadas are found throughout pre-history. The earliest known cicada was found in a fossil that is 65 million years old, dating back to the time of dinosaurs in the Cretaceous Period (think Tyrannosaurus Rex). In 1766 BC, the Shang Dynasty in China used cicadas as art. Five hundred years later, the Chou Dynasty used cicadas in religious ritual burials as symbols of the soul (cicadas often were placed in the mouths of the dead as symbols of resurrection).

Around 500 BC, cicadas were used in the artwork of ancient Greet coins. Around 350 BC, the bugs were kept as pets in some Greek households. They also were studied and written about by the great philosopher Aristotle in the same time period.

9. They're strict dieters

Cicadas don't eat much after coming out of the ground, but they do drink water. Researchers don't think there's much "food" in the liquid cicadas take in. Studies have shown that ants pass right over moist areas where cicadas have been "drinking," which indicates there is no sugar in the liquid the cicadas ingest. While underground, cicadas "feed" off the liquid in plant roots. Researchers believe there is nutritional value in that liquid.

10. The end will come quickly

Cicadas have to avoid being eaten from the first moments of their lives. When rice-sized babies hatch from their eggs, during the latter part of this month, they'll fall from branches and immediately race to the ground. There, they'll try to find a crack in the dirt to bury themselves for the next 17 years.

Birds, spiders and ants love to dine on the juvenile cicadas. So hanging around on a blade of grass is a death sentence. "Once they fall, they'll be underground within seconds," Kritsky says.

So many juveniles will fall from trees at the end of June that it will look like salt being poured from a shaker.

E-mail dklepal@enquirer.com