Curious about Curculio?
Does the character Gonzo of Muppet fame intrigue you? If so then you might be interested in one of our native insects. With its long proboscis and large eyes, the long-snouted acorn weevil (genus Curculio) is a common acorn insect, although you may have never seen it. These weevils are about ½ inch in length with a snout that is equal or slightly greater than the length of their body. They feed on acorns still attached to oak trees and use their small saw-like mandibles at the tip of their beak (which move vertically instead of horizontally as is the case with other beetles) to drill into the shell. Once this has been accomplished they feed on the nut meat within. Interesting also is the attachment of the two antennae to the snout reminiscent of Poseidon's trident, their form suggests that they may function as a brace to steady the "drill". The consumption/ destruction of acorns by the adults and larvae may exceed that of any other single acorn feeder i.e., deer, squirrels, blue jays. These other animals often get weevil "meat" instead of nut meat when they feast on acorns. At times the competition for acorns as food may leave few acorns to germinate.
Females, with longer snouts then males, often deposit their eggs through the hole in the acorn on which they have fed. The eggs hatch within a few days resulting in a legless, grub-like larvae. There may be several acorn weevil larvae in each acorn. There are typically five instars that occur over a period of a few weeks before the larvae chew their way out of the acorn. They then burrow into the soil to pupate, emerging as adults in a year or more.
To collect these larvae place newly fallen acorns into a five-gallon pail, keeping it out of the rain, at about 70° F and away from rodents, birds and deer. Usually within a week the larvae emerge. My father collects the "grubs" placing them in sawdust and refrigerating them for use as ice fishing bait. It has always been an important tradition in my family to keep a list posted on the door of the refrigerator as to what "bait" the plastic tubs within may contain. My mother came up with this idea and she doesn't even fish. Imagine that. She also has rules about using the washing machine for scaling bluegills or dislodging the spines on cucumbers.
If you would like to have Gonzos of your own, rearing the larvae is quite simple, however, even at room temperature this will take several months. Fill a five-gallon pail with moist soil to the depth of about 12 inches and place the larvae on the surface and watch them burrow into the soil. Check often to prevent the soil from drying out. You may want to place some sound acorns on the surface to provide food for the adults when they emerge. Cover the pail securely with window screen, watch, wait and enjoy.
This month's riddle...
What lives in the woods of northern Minnesota, weighs 7500 lbs, can fly long distances and is attracted to lights?
The answer is one acre's worth of forest tent caterpillars. Approximately 537 of the late instar larvae of forest tent caterpillars weigh one pound. Assuming that there can be up to 4 million caterpillars per acre that makes 7448 lbs of caterpillars per acre.
Residents of many northern Minnesota towns found their homes and businesses covered with forest tent caterpillar moths the morning of July 10th , especially if they had outside lights that stayed on all night. The moths are definitely attracted to lights. And, they can fly long distances in large masses. Some communities having little or no defoliation were suddenly swarming with moths. For example, there were no large areas of defoliation within fifteen miles of Grand Rapids, yet the morning of July 10th, buildings and sidewalks were covered with thousands of moths. Business owners were scooping them up with shovels trying to keep customers from tracking squashed moths into their stores.
Large numbers of moths were also reported in Region 1, especially in areas that weren't defoliated earlier this year. The western and northern areas of the Region experienced pockets of moderate to heavy defoliation this spring with other areas only scattered pockets of light defoliation. Those areas that escaped the rages of FTC in 2000 may have a better chance to enjoy all the notoriety and consternation of FTC in 2001.
You may not believe it, but, radar has been used to track the movement of clouds of moths, particularly, spruce budworm. Distances traveled can be 100 to 150 miles. Moths have also been encountered by aircraft far out to sea and at altitudes up to 4000 feet. Mass invasion by clouds of moths is often associated with thunderstorms and rain cells in advance of cold fronts. Rain showers and cold air downdrafts can dump millions of moths into small areas. In 1975, for example, moths were reported to be ankle deep on the ground beneath lights in Hardwood Ridge, New Brunswick. New outbreaks can start in locations far removed from the main body of the outbreak due to these mass invasions of moths.
More information on radar entomology can be found on the Internet at http://www.ph.adfa.edu.au/a-drake/trews/