The sweet aroma of black locust

Black locust trees blossoms are very fragrant


If your drive south of Frederick on U.S. 15 or elsewhere where you see black locust in bloom, roll down your window and enjoy the aroma, because this tree has one of the most pleasant scents around.

Black locust (Robinia pseudoacacia) is a deciduous tree native to the East. It is in the legume family, which means it is a nitrogen fixer, taking atmospheric nitrogen and depositing it into the soil in a form that other plants can use. Nitrogen fixers make the soil more fertile as a result.

Black locust is a quick-growing, relatively short-lived tree. It has very hard, rot-resistant wood used for fence posts and firewood. Locust is one of the major honey trees in the U.S. and has been widely imported into France for honey production.

Locust is hardy and tolerant of poor conditions, and it is often planted in land reclamation projects. It gets a bad rap as being an invasive plant because it quickly seeds into crop and abandoned fields, but this tree's role in ecology is to occupy a site, make the soil more fertile, then decline to allow older growing trees to become established.

It's a wolf spider's life

Wolf spiders are in the family Lycosidae and include more than 2,000 species worldwide and more than 100 species in the United States. They are ground-dwelling generalist predators that commonly inhabit and hunt in lawns, grass and leaf litter near the outer foundations of houses, outbuildings, in basements and under porches.

Credit: - Raphaël Poupon

Wolf spiders are hairy and large (.5 inches to 2 inches), robust and brown to black to gray in color. Like most spiders they have two body segments consisting of a fused head and thorax and an abdomen. Their eight long legs are covered with hairs that help detect air movement by potential prey or predators. They have fang-like mouthparts and venom glands. At the tip of the abdomen there are several silk-producing spinnerets. But, they do not use silk to make webs; instead, they construct burrows in the ground and use silk to line their shelter.

Mainly nocturnal hunters, they may ambush or run down their prey, which includes insects such as caterpillars, earwigs, ants, beetles, grasshoppers, crickets, roaches and other spiders. Wolf spiders use their legs to seize their prey and their jaws to hold and crush their victim. The fang-like mouthparts are used to inject venom and enzymes that start the process of digestion and make the prey nice and juicy for easier consumption. Wolf spiders hunt actively from late spring to fall. They can live up to four years.

An interesting behavior of wolf spiders is that females will care for her young. A female lays about 100 eggs and then encases them in a silk sac. She carries the egg sac under her body several weeks. When the eggs are ready, she tears open the silk sac and the spiderlings crawl onto the mother, covering her body. The spiderlings will hang on her for several days and then drop off and become independent.

A fun activity is to "headlight" for wolf spiders in your lawn. Wolf spider eyes reflect light and can be seen at night. At the right time of year you will be amazed at how many are active in your lawn. To do this, go out at night with a bright flashlight. Hold the light about head level and shine it out over your lawn. If you are lucky you will see hundreds of pairs of tiny red or green eyes reflecting back at you.

Excerpts from article by Paula Shrewsbury, University of MD Extension

Nature Notes for 5/9/2010