..... Stumper Index
Stumper #14.
H
o
w

g
o
o
d

i
s

y
o
u
r

s
c
i
e
n
c
e

K
Q
?

How Good Is Your Science KQ?

[i.e. your Knowledge Quotient]

- The lives of oak trees and insects intertwine -

Oak trees have acorns and from acorns new oak trees grow. Right? Yes, of course. But, did you know that oak trees may also have apples? And, if you were told that oak trees can grow marbles, spangles, even cherries and currants, would you believe it ?

Well, it's true. But read on. Oak-apples grow, often in clusters, from buds on small branches of oak trees and, green at first, they ripen to a rosy color. Marbles, most often found on young trees, grow at the tips of small branches and are corky, hard and brown when mature. Spangles are small and disc-like, and grow on the undersides of oak leaves often in groups of eighty or more. Cherries also grow on the leaves, and currants usually grow on the catkins.

As you probably realize, the Oak-apples, Marbles, Spangles, Cherries and Currants are not what they sound like. They are galls. They result from abnormal growth caused by the invasive and irritating effect that certain insects can have on the tissues of an oak tree.

[Note: Common names for galls differ from place to place so don't worry if you don't recognise the ones used here.]

Now, we have two questions for you to ponder:

a) To what sub-group of Insects do these oak gall-producers belong?

b) Do the oak galls result from the activity of these insects as they prepare to hibernate, or are the galls involved in the insects' reproductive cycle?


[Home]
Send feedback to
Explorit Science Center, P.O. Box 1288, Davis, CA 95617, USA
Phone: (530)756-0191     Fax: (530)756-1227