Take home final exam April 29th

DUE: May 5th in my office by 1pm

1100 to 1300 All classes meeting at 0800 or 0830 MWF

Exam format How many:•MC? (50%)•Short answer? (25%)•Essay? (25%)

Territory quality predicts helping behavior and sex of warbler offspring

•Female offspring are more likely to help parents•As open territories diminish helping increases•Higher quality territories can support more adults

Can it be that females produce more females to exploit open territories?

•Females produce female offspring to provide help•Is this a selfish strategy?•So long as female offspring help parents are they effectively a non reproductive caste?

Estimating the fitness benefits of altruistic behavior

The fitness value of your 1 child:N = 1; r = 0.5 Direct Fitness = 1x0.5= 0.5

Direct Fitness = (N1x r1)+(N2x r2)Indirect Fitness = (N3 x r3)Inclusive Fitness = (N1x r1)+(N2x r2)+(N3 x r3)

Your traits Your parents traits that help you

Helpful traits of your relatives

Now think carefully about inclusive fitness and altruism:•Do these concepts jive?•Is saving your three cousins altruistic?•How would a change in r affect the likelihood of evolving altruistic traits?

The fitness value of your 3 cousinsN=3; r=0.25Indirect fitness = 3x0.25=0.75

Altruism or selfishness: hymenoptera wasps

•Queens can directly control sex of offspring•All females are capable of reproducing but only some do.

•Conditional strategies:• Stay and help (primary helper)• Leave, bread & help another nest (secondary helper)•Leave, bread found a new nest

Why help an unrelated queen?Two explanations:1. To eventually take over the nest. 2. Opportunity to reproduce in an established nest

• Not competing with mom• Using someone elses established resources

Altruist or selfish?

Eusociality

Three characteristics of eusocial systems:1. The mother, along with individuals (related or not), conduct cooperative care of

young. 2. A reproductive division of labor emerges from sterile castes which often have

certain morphological/behavioral enhancements for conducting specific tasks. 3. Generations are overlapped allowing older generations to help younger

generations.

Insects:1. All known ant species2. Most bees3. Many wasps4. Termites (diploid) 5. Aphids and thrips (relatively simple guard caste only)

Crustaceans 1. Some shrimp

Mammals1. Naked mole rats

Most eusocial species are haplodiploid

Unfertilized these eggs would become males

Haplodiploidy means sisters are most closely related

What does this mean for measures of direct and indirect fitness?

Would this facilitate the evolution of eusocial species?

Who should a female worker bee help first?a) The queenb) A male offspring c) A female offspring

What if your mother mated with 2 or more males not 1?•In this case females average .5 relatedness•Male female relatedness becomes equal •Resources are more evenly distributed.

•If your more related to your sister than you’re your mother or brother then you’ll help your sister •In haplodiploid systems there is a 3:1 relatedness ratio between females and males and resources in these systems are disproportionatly distributed by females to females