Entomology Lab
May 3, 2012
Our Natural History class paid a visit to the entomology professor on the University of Washington campus. The first half of class was spent inside looking at specimens under microscopes and sharpening our sketching skills while the last half was spent outside near the farm at the bee observatory. Before dividing the class in half, we got a lesson on entomology, beetles, moths, and bees. Entomology is the study of insects (in theory) and land arthropods as well in reality. Insects and plants mostly evolved together and they are the most diverse organisms on the planet. We do not know how many species actually exist on Earth or how many have gone extinct, but the estimate for current living species is about 10 million. They represent a lot of natural history of the Earth because they are an important part in the food chain, especially for young salmons. Flies and dung beetles, for example, are waste recyclers. They help in soil and vegetation control, but some are most importantly pollinators. Only about 1% of them are actually pests. In the human world, insects are competitors to humans and animals for food (crop and forest pests). They are disease vectors such as mosquitos that spread malaria, but they can serve in biocontrol for agriculture. Some insects are actually nutritious so they serve as food in certain cultures and humans sometimes derive medicine from them. Most of the changes in an insect's life cycle happen during the larvae stage and when they mature to an adult, their main purpose is to reproduce.
Beetles - represent 1/3 of all insects and they are the most diverse. They have elytra (wings cases) that act as a defense mechanism, airfoil, or in aquatic beetles, they are used to exchange gas. Elytra are also the advertising mechanism for sexual selection. Some beetles are predacious, nocturnal, and small. The best way to collect beetles is to use a pitfall trap.
Moths and Butterflies - are some of the oldest things ever collected by biologists. Butterflies are actually moths; they are a specialized group. Moths are night-flyers and less colorful. Butterflies are day-flyers therefore need the colors, and most are not pests. In Washington specifically, sometimes swallow tails are mistaken for monarchs, however monarchs do not exist here. The best time to see them is late spring to summer and during the hottest part of the day. They rest under leaves when it rains. The best collection technique is to use a hand nest to practice the method of catch and release.
Bees - much like butterflies, bees are a group of wasps. They evolved tightly with plants because they are pollinators. All are stingers. They suck up nectar as an energy source when flying with a proboscis while obtaining pollen for their larvae. Pollen stick to their hair and they get rid of them by brushing/grooming it off to a pollen structure. Bees are small, drab in color and they build nests (hives). When a hive becomes too crowded, a swarm of bees will leave with the original queen to find a new location while some stay back and raise a new queen. A queen's job in a colony is to lay eggs while worker bees produce honey, care for the larvae and feed the queen. Bees do not "choose" their queen. Queens are fed more than worker bees to stimulate their sex organs while workers bees eat less to suppress their sex organs.
Bumble bees - the most conspicuous, social bees. They are often used in agriculture because they visit many, many flowers serving as a great pollinator. There are about six species in the Puget Sound area and all are intolerant to pesticides. Bumble bees can sting many times because their stinger does not break away. The current research suggests the decrease in local bumble bee population may be due to disease introduced by European bumble bees.
Honey bees - similar to bumble bees, however not native. They originated from west Asia and Africa, and have been to North America for about 300 years. Agriculture sometimes are dependent on honey bees because they are quite adaptive. You can move an entire hive to a different location without worry that their habits will be disturbed. Female honey bees are stingers (stinger break away), but males do not sting because their stinger is in a way connected to their reproduction device.
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