July 4, 2008
By Sue Benson,
CNHM, Director of Education
You may have noticed the monarch caterpillars on the milkweed, the just-fledged birds being brought into the feeder, and that dragonflies are everywhere. You might also be asking yourself, “What is that flower along the roadside? Why do some fireflies light up in the air and others on the ground? What are the things to watch for in nature right now?” The study of the annual recurrence of seasonal change is referred to as phenology. Summer is a great time to be on the look-out for these phenomena.
Start by looking for monarch caterpillars. They are more visible during this part of the season than any other time in the summer. The caterpillars feed only on milkweed plants and are immune to its natural toxins. These toxins give the caterpillars and adult monarch butterfly an unpleasant taste, which protects them from predation by birds or other creatures.
Dragonflies, the small rulers of the sky, are also abundant right now. The dragonfly life cycle consists of three stages – egg, nymph and adult. They begin their lives as a nymph living underwater, where they eat other aquatic creatures. In some species, this nymphal stage can last for as long as four years. When the nymph is completely grown and ready, it will crawl up the stem of a water plant and emerge, ready to change from an underwater predator into an aerial one. With almost a 360 degree field of vision and the ability to sight their insect prey up to 33 feet away, makes them a formidable predator. Adult dragonflies can live up to two months. They are also capable of flying speeds of 30 to 60 miles per hour and can travel up to 85 miles per day.
Another flying insect regularly active in the summer are fireflies. As young larvae, fireflies eat earthworms, snails and slugs – they actually sometimes follow a slime trail to the slug. After locating their meal they inject a fluid into their prey to immobilize and eventually digest it. As adults, each individual firefly species has a unique process for courtship. Flying males emit a pattern of flashes while in search of females on the ground. Females do not often fly, but respond to the males of their species with a similar flash pattern. Some females will mimic the mating flashes of another firefly species in order to prey upon the unexpected suitor.
A flash of color might also grab your attention as to what is blooming. Ox-eye daisies, a drought-loving flower common along the roadsides, are white with yellow centers. Orange and yellow hawkweed abounds, growing at least 10 inches tall, with a dandelion-like flower. It is said to have been given its name because people believed hawks would tear the plant apart and put its juice in their eyes to give them their superior vision. Keep an eye out for the bright pink fireweed and milkweed flowers and the yellow butter and eggs and bird’s foot trefoil.
Other neat things in nature to watch for include bass fingerlings moving in and out of wetland areas for food and cover, painted turtles hatching and evidence of raccoons having raided their nests, and the first cicadas buzzing. Wild blueberries are also usually ripening about this time. As soon as the sun sets, Saturn and Venus are close together in the western sky. Enjoy the “Once in a Blue Moon” opportunity as July has two full moons; the first on July 1 and the second on July 30.
Become a phenologist! It’s easy. The only prerequisite to participate is that you must live somewhere where there are bird songs and trees.
Brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. They invite you to visit their facility in Cable on 43570 Kavanaugh Street or at the website at www.cablemuseum.org to learn more about their exhibits and programs.