Even a small mating advantage for infanticidal males could lead to the maintenance
of this trait since the cumulative effect on the matriline is so small. Variation in
male success with the infanticidal/noninfanticidal strategies leads to the preservation
of the polymorphism.
14.2 Langur Infanticide Model Equations
Fertile(t) ¼ Fertile(t À dt) + (Weaning + Sexual_Mat À Fertilization À FDeath) * dt
INIT Fertile ¼ 10
INFLOWS:
Weaning ¼ CONVEYOR OUTFLOW
Sexual_Mat ¼ CONVEYOR OUTFLOW
OUTFLOWS:
Fertilization ¼ .25 * Fertile
FDeath ¼ .004 * Fertile
Is_the_male_in_the_population_currently_killing_babies?(t) ¼ Is_the_male_in_the_
population_currently_killing_babies?(t À dt) + (Change_in_male_state) * dt
INIT Is_the_male_in_the_population_currently_killing_babies? ¼ 0
INFLOWS:
Change_in_male_state ¼ IF Is_new_male_infanticidal? + Is_old_male_removed?
¼ 2 THEN 6ÀIs_the_male_in_the_population_currently_killing_babies? else if
Is_new_male_infanticidal? À Is_old_male_removed? ¼ À1 then ÀIs_the_male_in_the_
population_currently_killing_babies? else À1
Infant(t) ¼ Infant(t À dt) + (Female_Birth À Maturation À Infant_death) * dt
INIT Infant ¼ 5
TRANSIT TIME ¼ 9
CAPACITY ¼ INF
INFLOW LIMIT ¼ INF
INFLOWS:
Female_Birth ¼ .5 * Birth
OUTFLOWS:
Maturation ¼ CONVEYOR OUTFLOW
Infant_death ¼ LEAKAGE OUTFLOW
LEAKAGE FRACTION ¼ If Is_the_male_in_the_population_currently_
killing_babies? > 0 then (Extra_death_rate_due_to_infanticide
+Int_Infant_ Death_Rate) * Infant else Int_Infant_Death_Rate * Infant
LEAK ZONE ¼ 0% to 100%
Juvenile(t) ¼ Juvenile(t - dt) + (Maturation - Sexual_Mat - Juvenile_death) * dt
INIT Juvenile ¼ 5
14.2 Langur Infanticide Model Equations
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