[Ant Control] Keeping Invasive Species In Check

The first time they were spotted in the United States, in 2002, it was clear that these insects were different. They looked different and certainly behaved differently — erratically. And then, these cargo ship stowaways began multiplying — exponentially. As thousands, millions and then billions of them scurried about foraging for food, we discovered the impending danger.

Houston, we have a problem.

Actually, the problem goes well beyond Houston today, as Rasberry crazy ants have pillaged their way through at least 14 Texas counties in addition to infesting the nation’s fourth-largest city. Their favorite target? Electronics. Tiny enough to squeeze through minute cracks and crevices, these ants tend to cluster inside computers, shorting out circuits as they traipse over microchips. A major chemical company projects damages from this invasive pest to top $1 billion in its operations, and, had the Johnson Space Center not sought special consideration in its fight against the "crazies" in 2008, the critters could have feasibly brought NASA to its knees as well.

This is only one piece of a much broader story. Invasive pests are clearly a growing challenge to the pest management industry, and the more you know about how to handle them, the stronger your defense will be.

BACK TO BASICS. A good starting point for learning about invasive pests is reviewing the definition of "invasive species." A species is a specific population of organisms, morphologically and genetically distinct from other organisms, and capable of interbreeding. As opposed to a native, or indigenous, species, an invasive species is one that is introduced to an area from another place and then adapts to its new environment and spreads.

We don’t invite them. We don’t want them. And, as a general rule, we don’t become familiar with them until they’re right under our noses.

Most often tramp species — species that have been spread around the world inadvertently through commerce — these invaders have escaped from the natural predators, parasites and pathogens that would normally keep their numbers at bay. Without those natural means of keeping their populations in check, entomologists and pest management professionals are charged with the task. Entomologists seek ways to bring some of the pests’ natural enemies into their environments — for example, introducing phorid flies and disease-causing protozoa to southern states plagued with fire ants. Pest management professionals have pesticides as ammunition. Unfortunately, quite often, this ammo proves ineffective in controlling these imported pests.

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Taxonomy:
A Refresher Course

"Species" is the most basic category of biological classification — the lowest recognized classification designation. Insects come in a variety of species; however, they do have commonalities further up the taxonomic chain. In fact, all insects are considered part of the same domain, kingdom, phylum and class:

• Domain – Eukaryota

• Kingdom – Animalia

• Phylum – Arthropoda

• Class – Hexapoda

(also called Insecta)

Beyond this level, subdivision begins, including:

• Order

• Family

• Genus

• Species

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HOW THEY ARRIVED. Dr. Roger Gold, professor and endowed chair in urban and structural entomology at Texas A&M University, identifies several forces at work in the relocation of species:

• International commerce — Contaminated materials come into the U.S. from around the world, and our ports are just beginning to step up controls. Rasberry crazy ants (Paratrechina sp. nr. pubens) from the Caribbean, red fire ants (Solenopsis invicta) from South America and the destructive Formosan termite (Coptotermes formosanus) are examples of pests delivered through Gulf Coast seaports.
• Climatic events — Hurricanes and other acts of weather can move species. In recent years, a variety of insect species have "landed" in the United States via hurricane activity.
• Human activity — As people travel, especially internationally, bed bugs and other insects move with them.
• Research and biological control programs — As scientists investigate the possibility of introducing new species to other areas for specific purposes, occasional mistakes are made. Gold cites the spread of Africanized honey bees (Apis mellifera scutellata) or "killer bees." Recognizing the superior honey production of this subspecies, a team of entomologists began studying the possibilities for interbreeding them with domesticated honey bees. But conditions at their Brazil laboratory were apparently not as secure as the scientists had thought: "Like in a science fiction movie, a disgruntled employee released the bees, and they made their way north," Gold recounts.
• Bioterrorism — Gold says the government has concerns that invasive pests may be strategically released by terrorists intent on reducing our crop production, effectively disrupting our food supply.

HOW TO SPOT thEM. How do you recognize a new species? Gold suggests that you look for differences in appearance and behavior patterns, and resistance to pesticides. Non-indigenous species can exhibit any of three types of resistance:

• Physiological — A chemical or enzyme within the organism detoxifies or changes the pesticide molecule.
• Morphological — Something within the organism’s structural makeup keeps the pesticide from reaching the target organ.
• Behavioral — The organism’s behaviors steer it away from the pesticide.

"An example of behavioral resistance is red fire ants," Gold said. "This species, which is spreading quickly throughout the South, has undergone a behavioral modification in which the worker fire ants – sterile females — act as ‘the king’s taster.’ Any food introduced to the brood has to pass through the workers before it gets to the queens. This protects the reproductives from the pesticide, making the colony more resistant."

NEW SPECIES DISCOVERY. What do you do if you think you’ve discovered a new ant species? Gold points out the importance of sharing new species discoveries with government agencies, for a variety of reasons. Perhaps most importantly in the pest management industry, we may need new tools to manage these non-indigenous pests. Label restrictions may align with the species you encounter every day, but may limit your effectiveness when dealing with a distinctly different species.

Case in point: When Tom Rasberry discovered the first crazy ants, he keyed them out to see if they matched any existing species. When they didn’t, he documented his finding. That gave Rasberry, Gold and the rest of the team involved in the Johnson Space Center project the backing they needed to request a crisis exemption. The state government and EPA granted the exemption, which allowed the pest management team to go beyond existing pesticide label requirements to apply an effective dose that saved the center from imminent destruction.

"When you come across insects that look or behave differently, try to identify them," Gold said. "Go back to your textbooks or to the Internet and look up the keys to the major insect groups. If your insect doesn’t seem to fit, send a sample of it to a respected university entomologist or the USDA – specifically to APHIS, the Animal and Plant Health Inspection Service. It’s their job to document and respond to new species, traditionally in agriculture but now with urban pests as well."

Each state Department of Agriculture offers special local needs registrations, which give you the opportunity to seek support when you’ve identified a new species that is resistant to pesticides approved for similar insects. "It’s your responsibility to prove that this species is new and that nothing will kill it as effectively as the product you’re recommending," Gold says. "The federal government also gives you the opportunity to file for the crisis exemption in situations where the impending danger is of a critical nature."

Gold recommends working closely with manufacturers and distributors as well. "It takes the collaboration of a scientist who has collected the data, a local government representative (typically USDA or EPA) and a manufacturer interested in having its product go through the scrutiny necessary for these special registrations," he says. "If you manage the process correctly, you have the potential to prevent millions of dollars in damages." Fast response is critical to containment and control, Gold said. "Be observant in servicing your accounts, and tap into the variety of resources available to help you identify and document your invasive pest discoveries."

The author is a contributing writer to PCT and can be contacted at ddefranco@giemedia.com.