BIOLOGY OF SATURNIID MOTHS—BLEST 449 
of whose members possess eyespot patterns, while their near relatives 
are either aposematically colored, or are equipped with procryptic 
patterns. Eyespots are characteristically concealed at rest, and ex- 
hibited in response to disturbance by sudden movements of the por- 
tions of the body either bearing them or concealing them. What, then, 
is the relation between the distinct modes of behavior that might be 
expected to be linked with the various types of coloration and from 
what evolutionary source have they been derived? Numerous studies 
have testified to the close association between signal movements and 
the morphological patterns that they display (Tinbergen, 1952; Blest, 
in press [B]) ; here was an ideal case for a comparative investigation. 
The most readily available group of insects was the tropical Sat- 
urniidae, or “Emperor moths,” living pupae of which are freely 
available in the commercial market where they satisfy the demands 
of amateur lepidopterists. The results of this survey will be described 
later in detail; here we may note that it soon became apparent that 
a full understanding of the relationship between the different types of 
display could only be obtained by research in the field. 
In addition, yet another problem had revealed itself: the neotropi- 
cal hemileucine saturniid moths, whenever they settle into the rest 
position from flight, perform a rhythmic side-to-side “rocking”’ move- 
ment of the entire body, in which the head rotates through an are 
around the longitudinal axis of the body, and the legs of each side 
are alternately flexed and extended. This striking movement was 
first described by Dr. Margaret Bastock and myself (Bastock and 
Blest, 1958) in the Brazilian Automeris aurantiaca Weymer. A de- 
tailed analysis showed that, if the variants introduced by age are 
controlled, essentially the strength of the rocking response, as meas- 
ured by the number of oscillations performed, is influenced solely 
by the duration of the preceding flight performance, to which it 
bears a strictly linear relationship (fig. 1) (Blest, 1958). Now this 
relationship is of particular interest, for it is clearly very similar to 
that which the rhythmic components of the honey-bee communication 
dance bear to the distance flown between foraging ground and hive 
(Steche, 1957; Von Frisch and Jander, 1957). Since the bee dance 
is the only example of animal language that is comparable in its 
apparent achievement to our own, any evidence that may throw light 
on its physiological and evolutionary antecedents is of immense inter- 
est. Thus the causal basis of the moths’ behavior had to be deter- 
mined, as well as its role in communication or otherwise. 
In fact, no definite answers to this last problem of function have 
been obtained; but, to anticipate, we shall see that the results of 
observations on the rocking response can be combined with a knowl- 
edge of the protective displays to yield a new approach to a wholly 
distinct and quite fundamental problem in modern biology: the 
