Wednesday, August 20, 2008

Quiz Answers

Yesterday's quiz generated some good discussion about ants. Here are the answers to the quiz, with a few explanations.
1. Ants are close relatives of (c) bees and wasps. If  you said (d) aphids, you probably remember that there is a connection between ants and aphids, and there is. Ants are attracted by the "honeydew" aphids leave on plants - so they actually protect and care for aphids outdoors. But bees and wasps are the ants' close relatives, belonging to the insect order Hymenoptera.
2. According to San Diego County's website on ants, there are about (b) 200 species of ants in California. The website also states there are fewer than a dozen that are important. We are not sure how that makes the others feel. Among the most common are the Argentine ant, pharaoh ant, odorous house ant, thief ant, and the southern fire ant. To see pictures of each of these for purposes of identification, click here and scroll down.
3. Ant baits attract ants, inviting them to feed on poisonous bait and take it back to their nest. From a recent article on ant baits in PCT Magazine, we learn that the process whereby foraging ants bring food to those back in the colony is called trophallaxis. Workers collect fluids that are stored in the upper part of their digestive system, then regurgitate a portion of the stored food and pass it on to other workers, larvae, and queens. In fact, in some species, there are workers who remain in the nest, with the specific job of storing the fluid so it will be available in times of food shortage. This is the long way of saying the correct answer is (d) - ants eat the bait, then regurgitate it to feed ants back at the nest.
4. The chemical substance ants leave behind in a trail for others in the colony to follow is (a) a pheromone trail. The pheromones ants excrete are hydrocarbons that trigger a response to follow the path to food. Most ants renew the pheromones as long as the food is available. In some species, the ants actually mark trails that no longer lead to food with a repellent pheromone. Cleaning up an ant trail with a household cleaner can actually erase the pheromones and confuse the ants. But if the food remains, they'll be back!
5. Most ants we see walking around are (a) searching for a food source. Ants are always on a mission. The ones we see in our yards and homes are focused on foraging for food and getting it back to the colony. They do not need wi-fi, and have their own GPS.
6. This is a trick question. Give yourself credit for (a), since the ant queen is fed by the other ants. But the best answer is (c) - the queen is more like a slave or a prisoner. She doesn't order the other ants around, and is limited to her egg-laying role in the colony. Not a very glamorous life.
7. The best way to tell if you have Odorous house ants is to (d) squish one and take a whiff.  The identifying smell has been described as "rotten coconut." They are tiny, around 3mm in length, dark brown to black in color. Odorous house ants prefer sugary foods and fruits and usually forage in large numbers. These ants are less common than Argentine ants in San Diego, but now you know how to recognize one if you see one.
How did you do? Look for another bug quiz in next Tuesday's blog.

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