Biology Reference
In-Depth Information
brood. This provides evidence that it pays parents to respond to offspring begging signals.
Emlen (1995) reviews theoretical predictions for conflicts in families. The topics by Hrdy
(1999), Mock (2004) and Forbes (2005) are wide-ranging reviews of animal family
evolution. Houston
et al
. (2005) discuss models of sexual conflict over parental care.
TOPICS FOR DISCUSSION
1.
Why don't male mammals lactate?
2.
In penduline tits
Remiz pendulinus
sometimes the male deserts, leaving the female to care,
sometimes the female deserts, leaving the male to care, and sometimes both parents desert,
in which case the clutch fails (Persson & Öhrström, 1989; Szentirmai
et al
., 2007). Discuss
how these various outcomes might reflect sexual conflict.
3.
Discuss alternative hypotheses for weaning tantrums. How would you test these?
4.
Why under good feeding conditions might synchronous broods produce most surviving
offspring (Table 8.5)?
5.
Would you ever expect parent blue-footed boobies to intervene to protect their younger
chick from siblicide by the elder chick?
6.
In experiments with nestling tree swallows,
Tachycineta bicolor
, Marty Leonard and Andrew
Horn (2001) found that nestlings increased their rate of calling in the presence of a sibling.
They suggest that conspicuous and costly begging displays may evolve simply through
selection for effective individual signal transmission in the face of sibling competition for
parental attention. What evidence would distinguish this hypothesis from that discussed in
this chapter, namely that conspicuous begging has evolved to enforce honesty in signals of
offspring need?
7.
Discuss alternative hypotheses for the evolution of ornamentation in offspring. How would
you test these? Would you expect offspring ornaments to be less extravagant than male
ornaments?
8.
Compare the methods used to study sexual conflict over mating (Chapter 7) and parent-
offspring conflict over parental investment (this chapter). Could researchers on these two
topics learn from each other?
