Feature Article August 7, 2003
LAND O' LAKES NewsWeb HomeContact Us
Dog Days and CicadasWhy is hot, sultry summer weather in our area that occurs from about early July to late August often referred to as the 'dog days of summer'? We have to go back to ancient people in southern Europe. They watched the brightest star in the winter sky Sirius or the Dog Star, and correctly assumed that it would be in the sky the same time as the sun in summer. Because of this, they believed that it gave extra heat to earth, creating a period of hot, sultry weather, and this time came to be known as the 'dog days' - when the Dog Star was responsible for that extra warmth.
We really know the dog days are here when we hear the long, lazy, drawn-out call of the cicada. There are a number of different species in North America, but the one we are probably hearing is the Dog Day Cicada (or Dog Day Harvestfly). Sitting up there in a treetop, a male cicada is trying to lure a mate with its drone, which is produced by muscles attached to a pair of drum-like membranes on the base of the abdomen and causing them to rapidly vibrate. When you hear the drone or buzz sputter to a halt, the muscles are tired and the insect stops to rest.
Consider the life of a cicada. Once mating occurs the female will cut small slits in tree twigs and insert eggs. When the young hatch they will drop to the ground and dig down, from two to several feet, to where they can feed on the sap from the tree's roots. There they will live and grow and sleep until adulthood. Depending on the species, this time may be anywhere from 2 to 17 years. Instinctively each species will dig its way to the surface and at the right time emerge, crawl to a vertical object (most probably the tree at whose roots it has been feeding), molt into the adult form by splitting open its skin, fly to the treetop, mate, and die!
For the Periodic Cicada found in the United States, with its 17 years of dormancy, it may only be out in the sunshine for a very few weeks! Not known to feed as an adult, its sole purpose seems to be just that - mate, and die - unless it is just a scout to warn us to enjoy summer as its end is near!
You may find the translucent, brown, hollow 'shell' of the nymph on twigs or tree trunks, and if you look closely at the ground below you may see a small (about 5/8") hole where the nymph has emerged from its underground burrow. It is not easy to find the adults, but there is one creature that has been waiting for them, and that is the Cicada Killer, a large, solitary wasp.
These wasps feed on nectar and pollen, but a mated female will dig a burrow, hunt for a cicada on the tree trunks, sting to paralyze it, then carry it, still alive, to the burrow, where she will lay an egg on it, and it becomes a fresh food source for the young larva that hatches. When that larva emerges as an adult the cycle for both the cicada and wasp will be repeated. Such is nature.
Observations: Jul 31 - a Walkingstick nymph on my door. What have you seen? Call Jean Griffin at 268-2518.
