Survival Strategies

Six inches of rain fell during two days of steady showers leaving considerable surface flooding across the flat Arkansas Delta. Broad fields, harvested recently, became shallow lakes. The North wind blew crop debris of twigs, stems, and leaves to form long bands of floating vegetative matter. Numerous dinner plate sized masses of fire ants floated on these rafts of ground-up soybean plants shown in today’s photo. Fire ant colonies, which live underground, were being transported to dry ground on floating crop debris. Not only were the fire ants being saved from drowning by their huddling on floating matter, they were also expanding their range across open fields.

Honey bees expand their range through swarming, usually in the spring but to a lesser extent in the summer and fall. When the bees swarm, the colony divides; half of the bees stay behind, and half of the bees fly away. Sometimes all of the bees in a colony abandon their hive and fly away in a move called “absconding.” Bees will abandon their hive if the nest gets badly damaged, as when flooded or overrun and “slimed” by small hive beetles. At times, bees abscond during times of extreme dearth. Honey bees in the tropics tend to abscond more often than bees in more temperate areas. Tropical bees don’t have the need to store great amounts of honey to survive the winter. Seasonal changes in tropical nectar and pollen flows vary with rain and drought. During a dearth of nectar, tropical bees will abscond and move to areas where flowers are blooming. Honey bees in temperate areas survive by hoarding honey to provide food and energy for the winter. Each of these behaviors by ants or bees illustrates a heritable survival strategy which allows the insects to survive in a changing environment. Two studies hint at the mechanisms for the inheritance of survival traits: http://www.sciencedaily.com/releases/2011/12/111205102713.htm#.Tt7BaeNFBZY.email looks at methods of fighting viruses, and http://www.livescience.com/7655-lizards-dance-avoids-deadly-ants.html reveals how lizards learn to avoid fire ants.

--Richard

Fire Ants: An Invasive Pest

While examining a bee hive, I dropped a frame of bees and brood. Actually, I didn’t drop the frame; I really threw it back into the hive. A good beekeeper knows to always maintain a good grip on everything associated with a bee hive. Both embarrassed with myself and maddened, I looked to see why I did this. I saw that both of my hands were covered with stinging fire ants. These invasive fire ants are moving through the Arkansas Delta. I found the first two fire ant hills on Peace Farm three years ago. The following year, I found a dozen. By the next year there were hundreds of the over foot-tall ant hills. Now I am finding the fire ants living in our bee hives. The fire ants are establishing colonies between the outer and inner covers of the bee hives. In the photo, you can see the red and dark brown fire ants carrying their larvae past the half-inch tall letters left on our equipment by our branding iron. Two fire ants, social creatures, share the task of carrying one larva.

It is always difficult to control an invasive species. Plants or animals that are introduced into a new ecosystem often lack the creatures that helped regulate their populations in their original location. The fire ants may be replacing native ant species, which we try to protect and use as part of our integrated pest management program. There are insecticides available for use against fire ants. These may be effective; however, there is always the possibility of pests becoming resistant to chemical agents. Mechanical or biological control measures often prove to be better over time. There are few ways to mechanically control fire ants, which live deep in the soil. An educational partnership of universities in the United States, called eXtension, reports on a biological control being tested using a natural predator of the fire ant, the phorid fly. You can get more information about fire ants and see some of the research approaches being used at their web site, http://www.extension.org/fire+ants. I know that I will be doing some more research. Right now, the fire ants seem to have the upper hand.
--Richard