Discussion 
335 
QUESTION: Does your classification sys- 
tem of the type A limifrons display mean 
that there is no difference between courtship 
and aggressive display? 
JENSSEN: That is true inasmuch as the 
basic physical signal is the same. However, 
the recipient of the signal is different in the 
two social contexts. The A display appears 
in many contexts such as assertion, court- 
ship, and challenge. Therefore, its meaning 
is probably determined by the characteristics 
of its social context, its modifiers, and its 
recipient. 
DISTEL: In species having several display 
types in their repertoires, do different display 
types have different effects on the receiving 
animal ? Do different signals mean some- 
thing? 
JENSSEN: There is no direct way of 
knowing how the signal is perceived and 
interpreted. One can only look for correla- 
tions. 
REGAL: Neil Greenberg showed us how 
certain patterns would change throughout 
the day. Have you seen an indication of daily 
variability or a rhythm in social activity? 
JENSSEN : To detect any circadian 
rhythm in displaying would require much 
field data. This I do not have for limifrons, 
but for nehulosus, activity generally was sup- 
pressed during the warm hours of the spring 
days. From about 1130 to 1430 the ambient 
temperature was above the preferred body 
temperature and displaying was rare. Mov- 
ing about and socially interacting at these 
hours was also infrequent. 
GANS: I am a little unhappy with the 
analysis of complex movements of this kind 
based entirely on the position of the head. 
There may be all kinds of things happening 
here which are not critical to the way in 
which the animal gets its head up and down. 
If that is all it is, then it does not matter 
for the signal whether the animals gets its 
head up and down by moving the arm and 
neck or by pushing with the shoulders. But 
if the receiver is looking at the shoulder 
movement rather than just the head move- 
ment, then it becomes very critical. 
JENSSEN: I agree. The display-action- 
pattern graphs only depict how the head 
moves through time. The next thing to do 
is what you suggest. In my descriptive 
scheme, the contribution by various effectors 
to the production of the bob pattern should 
be quantified. The variations in movement 
of these body parts would most likely be con- 
sidered modifiers. However, from a func- 
tional standpoint, how the extent to which 
the body parts are moved actually affects the 
information content of the display is a much 
more difficult question to find answers for. 
GARRICK: I have a few observations 
about lizard signaling systems. Examination 
of three papers reporting displays of diurnal 
lizards showed that they combine and use 
signals in varied ways. Consider the follow- 
ing: (1) Composite displays are common 
among iguanid lizards that employ head 
nods, bobbing of the body or push ups, and 
extension of the throat fan. Separate displays 
are linked together temporally to form vari- 
ous combinations, e.g., the signature bob of 
Anolis aeneus (Stamps and Barlow, 1973, 
Behaviour, 47 :67-94) ; (2) Graded displays 
employing the common Iguanid components 
were described for a series of male displays 
by chuckwallas (Berry, 1974, UC Publ. Zool. 
101:1-60), and Carpenter (1967, W.W. 
Milstead, ed.. Lizard Ecology, Univ. Mo. 
Press) observed a grading of intensity be- 
tween assertion and challenge displays; (3) 
Individual recognition based on bob pattern 
were noted for Anolis aeneus and Sauro- 
malis obesus by those workers mentioned 
previously; (4) The same display may be 
used in many different situations, e.g., flag- 
ging display of Anolis nebulosus (Jenssen, 
1970, J. Herp. 4(1-2) :l-38), and different 
displays may be used in the same social 
situations, e.g., the use of flagging and flag- 
ging-assertion displays by dominant males 
approached by females (Jenssen, 1790) ; and 
(5) It is also obvious that the entire problem 
of syntax, or order of a particular display 
or group of displays in the individual’s 
sequence or its position in the complex signal- 
ing dialog between two lizards, should be 
examined very closely. 
