Alien species are invading New Mexico: the six-legged kind. They include little green bugs as well as red ants, bad-tempered bees and pointy-snouted weevils.

It's no reason to play the "X-Files" theme, though. Unlike two-legged aliens, invading insects have no diabolical plans to conquer the world. "They're just surviving," says Carol Sutherland, entomologist with NMSU's Cooperative Extension Service. "But they respond to opportunities and can cause problems for people who are trying to farm or garden or keep a lawn looking nice."

With insects already outnumbering humans by more than a million species to one, it's a good thing for us that the vast majority of insects are friendly. But in a new world, away from their natural enemies, some invaders live long and prosper, much to farmers' distress. Just one bad bug like the boll weevil can shift production in an entire industry and change a way of life, as cotton farmers in the Old South know.

Insects aggressive enough to travel thousands of miles to alien lands-like Africanized honey bees-pose threats to human and animal health. Invaders like the red imported fire ant can overwhelm native insects and trigger quarantines for the greenhouse industry.

Monitoring the invasion: Research assistant Tricia Yates and Jane Pierce check cotton bollworm traps in Artesia.

If you are an invading insect, New Mexico is hardly your idea of Utopia, says Jane Pierce, an Artesia-based entomologist with NMSU's Agricultural Experiment Station. It's too dry year-round for many insects, which flourish in humidity. Freezing temperatures are usually a death sentence.

"In Texas, Mississippi and Florida, where it's more humid, they have more and bigger bugs, many bigger than your thumb. In Central America and the tropics, some insects are as big as your fist," says Pierce, whose experience includes Peace Corps work in Belize. "New Mexico is not great bug territory."

The state's variety of crops, grown on small acreages, means that pests have to travel farther to find food and habitat. "We have an advantage that we're so diverse in our crops in New Mexico," says Woods Houghton, Eddy County Extension agent. "A big cotton field is 40 acres here. It's not like California, where it's wall-to-wall solid cotton."

An NMSU crew uses sweep nets to collect insects in an alfalfa field.

In general, New Mexico has fewer insect problems than its neighbors. "We're a transition zone between California and Texas," says Joe Ellington, an entomologist with the Experiment Station. "Our growers probably don't realize how lucky they are."

Alfalfa, New Mexico's top cash crop grown in every county, is home to one of the best defenses against invaders: beneficial insects. Lacewings, ladybird beetles and parasitic wasps prey on pests.

"Alfalfa is a reservoir for myriad beneficial insects and only a few harmful ones, most of which affect only alfalfa," Ellington says. "Every time it's cut, the beneficials are flushed out into crops." An alfalfa field may contain 1,000 different insect species, compared with 500 in a typical cotton field.

Pierce was struck by the sheer numbers of beneficial insects in New Mexico. "Sometimes there are so many tiger beetles, it looks like the ground is moving."

Back in 1954, the first confirmed sighting of the spotted alfalfa aphid in the United States was made in Roswell, seven years after the infamous Roswell Incident. Entomologists think the aphids, which were found in a field across from Walker Air Force Base, stowed away on a jet instead of crashing to earth in a spaceship.

Since then, the number of insect invasions has steadily increased. Over the last 45 years, other invaders have blown in on winds from the Gulf of Mexico and hitched rides on grain, nursery plants, wooden crates and moving boxes.

The 1960s saw the pink bollworm and pecan nut casebearer make their way to the Pecos Valley. In the late 1980s, New Mexicans uneasily welcomed a wave of boll weevils. A shift in the wind carried the Russian wheat aphid to the High Plains.

This decade, New Mexico has intercepted more and more invaders capable of doing serious damage, Sutherland says. "From a historical perspective, I think we've picked up a lot of speed."

In the early 1990s, the pepper weevil reappeared for the first time in a half-century, Africanized honey bees tiptoed into the Bootheel region, and the hickory shuckworm and pecan nut casebearer infiltrated the Mesilla Valley. In 1995, boll weevil populations in the state's cotton-growing areas ballooned after several mild winters. In 1997, Japanese beetles showed up in nursery stock. In 1998, the red imported fire ant bit a Mesilla Park woman, setting off quarantines. Just this year, the dreaded pecan weevil resurfaced in New Mexico orchards.

Though they offer a good defense, New Mexico's climate, crop diversity and beneficial bugs can't keep out every invader. Far from their homelands and natural enemies, insects can drive farmers into the ground.

"We have to be clever in New Mexico to compete with farmers who have more resources and land," says Mike English, entomologist and superintendent of NMSU's Agricultural Science Center at Los Lunas. "Very few farmers can go a year or two without a crop when insects strike."

Aphids attack: Russian wheat aphids caused a scare in New Mexico before weather,predators and informed farmers caught up with them. (Courtesy of Darrell Baker)

When a new species enters the state, reseachers, regulators and Extension agents scramble for ways to contain crop damage.

"When new insects invade, the first year or two they are extremely virulent," English says. "Then what usually happens is that natural predators and parasites, biological cycles and educated producers catch up with them."

Such was the case with the Russian wheat aphid, which blew into the United States on unseasonably strong, warm winds from Mexico in 1985 and 1986. The little green aphid one-sixteenth of an inch long-threatened to bury eastern New Mexico wheat growers.

"Russian wheat aphid can completely destroy the head of the grain," says Darrell Baker, superintendent of NMSU's Agricultural Science Center at Clovis. "It sucks the sap out of the plant and transmits a toxin that destroys the chlorophyll so the leaf can't manufacture food."

As the aphids feed, little or no pollination occurs because grain heads are distorted. The flag leaf, responsible for up to 70 percent of wheat yield, is decimated.

When wheat isn't available, the Russian wheat aphid shifts to grassy weeds and native grasses. In eastern New Mexico, many dryland farms border rangeland and hundreds of thousands of acres were planted in grasses for the Conservation Reserve Program, a federally funded effort to remove erosion-prone land from production.

Worst of all for wheat growers, the Russian wheat aphid invasion coincided with prolonged drought and low grain prices. Emergency pesticide exemptions allowed farmers with heavily infested fields to spray, the only immediate defense against the onslaught. Researchers with the U.S. Department of Agriculture released parasitic wasps that are natural enemies of the Russian wheat aphid.

A decade later, the Russian wheat aphid is still around but poses less of a threat.

"A lot of things helped," Baker says. "After two years, the prevailing winds were coming from the wrong direction. They moved north with El Nino." During the dry years, less wheat was planted, and fall weather was unfavorable for insects.

Right now, New Mexico is facing down three of its worst invaders ever: the boll weevil, red imported fire ant and Africanized honey bee. The boll weevil threatens the existence of the state's cotton industry. The fire ant, which packs a venomous sting, spells trouble for New Mexicans, the greenhouse industry and native ants. Aggressive Africanized bees are a threat to public health.

Carol Sutherland shows a cotton square the size of a pencil eraser.

All three of these invaders traveled great distances to get here and seem determined to stay. "Nothing's stopped them yet," Pierce says.

The slogan for the U.S. Department of Agriculture's boll weevil control campaign sums up New Mexico farmers' sentiments: Deliver us from weevil. The pointy-snouted pest has forced farmers elsewhere to diversify or go out of business. Its appetite for cotton has inspired songs, statues and sports mascots like Bo the Weevil from Piedmont, N.C.

The nation's most damaging cotton pest waited almost 100 years after its first foray into the United States to turn west to New Mexico's cotton fields.

The boll weevil had made brief stops in New Mexico before, but traditional wisdom said it wouldn't set up housekeeping here. Five mild winters in a row opened the door for a population explosion beginning in 1995.

"This was a big surprise for everybody who figured that New Mexico was bulletproof, because we're supposedly too far away from the action or we don't have the right climate to sustain this pest," Sutherland says. "Lo and behold, our cotton is just as tasty as the next guy's."

Sutherland checks traps in a Mesilla Valley field.

In spring, boll weevils feed on developing cotton squares, which drop from plants, slashing yields. Females lay their eggs in surviving squares or small bolls. The bolls either fail to reach marketable size or are riddled with larvae.

To say boll weevils are prolific is an understatement. Unchecked, a single pair could multiply into a billion weevils during the growing season. Five to six generations are produced each year.

After glutting themselves, weevils look for a place to spend the winter. "At this point, they don't need food because they're chock-full of fat," Sutherland says.

Pierce's research has shown that weevils survive best in shinnery oak native to Lea County or in weedy borders and urban backyards in the Pecos and Mesilla valleys. They've been found hibernating under shingles and even trying to burrow into the hides of livestock.

Though it's a fierce foe, the boll weevil does have a weakness: It reproduces only in cotton. "We rarely think about eradicating an insect," Pierce says. "But the boll weevil is such a damaging insect, and it has certain characteristics that allow us to consider eradication."

Farmers in southcentral New Mexico and the Mesilla Valley have formed eradication districts. A surcharge on each bale of cotton funds a mandatory spray program.

Though the boll weevil has the potential to end cotton production in New Mexico, success stories in other states keep farmers fighting. Eradication programs in Georgia and the Carolinas have allowed cotton production to resume.

"Farmers in other parts of the country have lived with the boll weevil for a long time," Houghton says. "I do think it will change the way we farm."

In the Pecos Valley, where mandatory treatment programs have been narrowly defeated in grower referenda, farmers are cooperating to battle the boll weevil. They are controlling weedy borders to eliminate hibernation spots and planting later so weevils emerging early in the spring will starve to death.

Farmers with infested fields are advised to spray in late June, when squares are the size of matchheads-too small for weevils to lay their eggs in. "That is the one time during the year when one application can have a big impact," Pierce says. "Once they get past that point, you need three applications for similar control. That's too expensive."

This summer, Pierce and Ellington are collaborating on beneficial insect releases of Catolaccus, a parasitic wasp that preys exclusively on boll weevil. "This is not an insect that will become established on its own," Pierce says. "If it works, we will have to do releases every year, and it will be expensive."

Ironically, one of the boll weevil's worst natural enemies has established itself in New Mexico. "The only really good predator of boll weevil is imported fire ant, but we don't want that," Pierce says.

After making a stop in Hidalgo County more than 10 years ago, the red fire ant established itself in Dona Ana County, where it was found in 1998. An 85-year-old Mesilla Park woman was stung repeatedly while stomping ants on her front sidewalk one morning on the way to church. Reports of the welts on her legs, characteristic of the fire ant's venomous stings, attracted entomologists' interest.

Scoping out pests: Sutherland uses a microscope to positively identify invaders.

"I popped the ants under the microscope and went, 'Uh-oh, these have all the features of red imported fire ant,'" Sutherland recalls. To confirm her identification, she sent samples to the USDA.

Children, the elderly and pets are particularly vulnerable to fire ants. When disturbed, the ants are prone to attack. They bite, then sting, injecting venom that creates an itchy, raised weal. "You can easily receive quite a charge of protein and organic acids in your blood," Sutherland says. Allergic reactions to stings, though rare, can be fatal.

The fire ant also threatens to take a bite out of New Mexico's greenhouse sales. Because it can be transported in soil, nursery products and dirt-encrusted equipment, the pest's presence has triggered a quarantine for Dona Ana County.

"The redeeming feature of the quarantine is that products produced here can still be sold outside the quarantine area," Sutherland says. "But they must be treated, processed or manufactured in a way that minimizes the likelihood of any kind of fire ant activity on them." Producers have to check with the New Mexico Department of Agriculture to make sure products are properly treated before shipping.

Red imported fire ants swarm over a mum in a Mesilla Park yard.

New Mexico may provide a less hospitable environment for red imported fire ants than southeastern states. The ants will have to overcome high temperatures, alkaline soils, limited moisture, competition for food and human resistance.

"Here in the Southwest, the red imported fire ant may be a little bit out of its element," Sutherland says. "I think probably where it's going to have its best success will be in our irrigated valleys or in places where there's water available."

Although red imported fire ants prey on pests, they also conquer native ants. "They tend to dominate once they move in and can pretty well kick out all the other ants," Sutherland says.

The fire ant is a distant cousin of another aggressive invader, the Africanized honey bee. While the ants probably stowed away on soil or cargo from South America, the Africanized honey bee was accidentally launched by well-meaning efforts to increase honey production in Brazil.

Bees thought to be better foragers were brought from Africa to Brazil, where they escaped and established themselves in the wild. Since 1957, the bees have been moving steadily northward.

When threatened, Africanized bees defend the colony with their lives, stinging in much greater numbers than the tamer European bees used for pollination and honey production.

Africanized bees were first found in the United States in Hidalgo, Texas, in 1990. "When watching the infestation patterns in Texas, you could practically play connect the dots by following rivers and creeks along watersheds, a major one being the Rio Grande," Sutherland says.

Seeing double: Italian and Africanized honey bees are identical to the naked eye. (Courtesy of Texas A&M University)

In 1993, the bees showed up on a New Mexico ranch near Cotton City, 25 miles south of Lordsburg. To date, they've been found in eight counties: Catron, Grant, Hidalgo, Luna, Dona Ana, Otero, Eddy and Lea. In Bernalillo County this year, scientists found European bees with signs of African crossbreeding.

Rather than heading for greener pastures to the east, the bees have struck out across the desert. They can subsist in lonely spots with only a windmill for water and wildflowers or sweet cattle feed to eat.

"They'll use up a food source until it's gone, then they'll consume whatever they have stored in the nest, including the offspring, and abscond," Sutherland says. The bee colony divides, usually in the spring, and a swarm sets out to establish a new hive.

When startled, both Africanized and European bees can be dangerous. Several New Mexicans have survived encounters with bees in which they suffered hundreds of stings. For those allergic to bee venom, even one sting could prove fatal.

"They're wild animals, just like bears or rattlesnakes," Sutherland says. "Each and every worker bee is armed with a sting, and she'll give her life, if need be, for her colony."

Meanwhile, bees are under attack from two tiny new invaders, the varroa mite and honey bee tracheal mite. And more invaders are on the horizon for New Mexico. This year, the pecan weevil, which could devastate orchards, is making itself known.

With global trade and international travel, insects will keep moving in, often with help from humans. "You're never really safe from invaders," Sutherland says.

Giving foreign bugs a green card