Alcock10e Ch03 Discussion Questions - Instructors Manual to...

Instructor’s Manual
to accompany
Animal Behavior, Tenth Edition
John Alcock
Discussion Questions
Chapter 3: The Evolution of Social Behavior
Figure 3.3 shows a phylogeny (see page 31) of many bee species in the genus Lasioglossum
with the social system of the species superimposed on the evolutionary tree. What is the
minimum number of times that eusociality (i.e., colonial species with obligately sterile
workers) has evolved in this group? How many times has eusociality been lost, either
completely or partially? (Partial loss of eusociality has occurred in those species that are
labeled “polymorphic,” which means that in these cases some populations form colonies
with sterile workers and others do not.) How might this phylogeny be used to criticize the
common value judgment that complex social systems are generally superior, and more
recently evolved, than simpler ones?
,
3.2 Given the differences in reproductive success for the three categories of male lazuli
buntings, how can we account for the evolutionary persistence of males with dull and,
especially, intermediate plumage?