Nature Notes

Vol. V August 22, 1927 No. 8


Dr. Crosby, entomologist of Cornell University, is in the Park on the trail of small spiders. Among other things the Doctor has discovered that we have a tarantula native to this region. For years we have been telling people that we have no poisonous snakes in the Park, and now they tell us we have something which sounds just as bad to many people. There is no need for fear, however. Most people think of a huge, black, wooly spider with a poisonous bite when tarantulas are mentioned, but those are only one variety of a large family. The one found on Rainier, (Longmire Springs) is another variety of the same family but he is a small harmless spider.

The Doctor has also refreshed our memory on the very interesting life-history of the aphis or plant lice. Plant lice are very abundant at present on the giant helebore - the plant from which an insecticide, helebore powder, is made. Aphis do not go through the same larva and stages as most insects do. Small aphis look very much like adult except in size. After shedding their skins three times they are adults. Several generations of young are produced each summer and they are all females. What's more, they are born alive, contrary to all rules of insect conduct. Late in the fall males and winged females are produced. These females deposit tiny black, watermelon-shaped eggs which carry over the winter and in the spring hatch into females are called "stem mothers". These "stem mothers" produce the summer generations again but do not lay eggs.


Aphis, or plant lice, excrete a sticky fluid called "honey dew" which bees and ants are very fond of as a diet. Bees content themselves with gathering the honey dew from the leaves but certain ants go farther. These ants keep plant lice captive, stroke them to stimulate the secretion of honey dew and thus have a handy food supply.

In fact, it can almost be said that these ants are stock raisers and dairymen as they often care for the eggs and young of the aphis in order to secure as "dairy herd". Dr. Crosby tells of watching ants take the aphis eggs from dying plants and remove them to their burrows to carry over the winter. If the eggs become damp they take them out to dry. When the young hatch they feed them by placing them on growing plants. Later they "milk" them. If food becomes scarce the ants will sometimes eat the aphis just as human beings do with their cattle--if meat becomes more to be desired than milk then the dairy cow becomes "beef".

By F. W. Schmoe, Park Naturalist.

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