The Lady Beetle Essay, Research Paper
The Lady Beetle. Lady beetles, often called Ladybugs or coccinellids, are the most commonly known of all beneficial insects. Both adults and larvae feed on many different kinds of soft-bodied insects with aphids being their main food source. Farmers and even some small household garden owners often buy them in bulk and release them in there gardens. Ohioans like lady beetles so much that the Convergent Lady Beetle became the official state insect in 1975. Adult lady beetles are domed shaped, oval or convex, and are often shiny with short legs and antennae. There wing covers are dark reddish orange to pale yellow, with or without black spots or irregular marks. Some lady beetles are solid black or black with red spots. The head is concealed from above and they have six distinct tarsi (feet). Lady beetles range from 1/16 to 3/8 inch long. Most Lady beetle larvae resemble tiny, six-legged alligators that have been painted blue-black with orange spots, and have large, sickle-shaped mandibles (jaws). The length of a lady beetle’s life cycle varies depending upon temperature, humidity, and food supply. Usually the life cycle from egg to adult requires about three to four weeks, or up to six weeks during cooler spring months. In the spring, overwintering adults find food, then lay from fifty to three hundred eggs in her lifetime (tiny, light -yellow eggs are deposited in clusters of 10 to 50 each) in aphid colonies. Eggs hatch in three to five days, and larvae feed on aphids or other insects for two to three weeks, then pupate. Adults emerge in seven to ten days. There may be five to six generations per year. In the autumn, adults hibernate, sometimes in large numbers, in plant refuse and crevices. Lady beetles, both adults and larvae, are known primarily as predators of aphids (plant lice), but they prey also on many other pests such as soft-scale insects, mealybugs, spider mites and eggs of the Colorado Potato Beetle and European Corn Borer. A few kinds of lady beetle feed on plant and pollen mildews. One larva can eat about 400 medium-size aphids during its development to the pupal stage. An adult will eat about 300 medium-size aphids before it lays eggs. Around three to ten aphids are eaten for each egg it lays. More than 5,000 aphids may be eaten by a single adult in its lifetime. The lady beetle’s huge appetite and reproductive capacity often allow it to rapidly clean out its prey. There are a few species wish are plant feeders and one of these, the Mexican Bean Beetle (Epilachna varivestis Mulsant), can be a serious problem in bean crops. During the autumn, lady beetles crawl to overwintering sites where a few to several hundred will gather in an aggregation. The aggregation site may be located at the base of a tree, along a fence row, under a fallen tree, or under a rock. Beetles are often found under leaves which protect them from cold winter temperatures. Sometimes beetles become a nuisance by settling in and around peoples homes. Some will gather in large numbers on the sunny side of a house. Caulk and seal spaces and gaps to prevent them from coming inside. Physically remove lady beetles found indoors. Since lady beetles are beneficial, insecticide treatment is not suggested.
Lady beetles have some interesting means of protection. Their red or orange and black coloration warns birds that they would not make a very tasty meal. Birds learn that insects that are red and black or yellow and black usually sting or taste bad so they leave them alone. Lady beetles of course can not sting but they probably do taste bad. They also will “play dead” when in danger. Many predators will not eat an insect that doesn’t move. Also, lady beetles produce a bad smelling odor by way of a fluid from joints in the legs, which can help to protect them. Lady beetle dealers collect there beetles in the mountains. The reason for this is that the beetles often congregate in huge numbers in colonies or aggregate in the same sites year after year. Some colonies have been reported to contain as many as 500 gallons of beetles. A gallon of beetles contains from 72,000 to 80,000 adults. The behavior of Hippodamia convergens (your common lady beetle) collected from mountain aggregations after the month of May and then released during the summer, is quite different then the behavior of the beetles collected from aggregations during the winter and early spring months and released in the spring. The beetles released in the summer remain for the most part in the areas that they were released. However, their feeding habits are not normal. They will drink water, but have no appetite since they apparently are able to exist on their stored fat. The release made in the spring months usually involves beetles collected from the mountain aggregations in the winter months before normal beetle migration out of the mountains. When winter-collected beetles from the mountains are released, they are apt to disperse quickly and widely, especially when the temperature reaches 65F and above. As a consequence, only a few beetles may remain in the area where they were released. Therefore, the beetles cannot be relied upon to control a potentially growing aphid population. There is no denying that lady beetles are beneficial insects, and are good to have around. But what this information does show is that to use shipped-in beetles in your backyard to manage pest insects is probably not a good idea. It also shows that beetles collected from distant states and shipped to other locations may be of less value as a pest eater than local beetles. It would be better to rely upon local beetles to distribute themselves and multiply in accordance with nature’s balance. Purchased H. convergens often fly away from gardens, but are effective for a greenhouse if vents are screened. You can collect natural, local species from hay or grain fields. Lady beetle suppliers recommend “Release Rates” for gardens and greenhouses is one-half pint (about 4,500 beetles) to cover 3,000 sq. ft. You should release beetles in the evening after watering down the area. Adult beetles are shipped in cotton bags mixed with wood shavings. Beetles are shipped air freight for quarts and larger, and first class mail for the smaller sizes. Prices range from 2,000 Lady beetles for $7.50, to 1 quart (18,000) for $26.50, to 2 gallons & up for around $62.00.