Pied kingfishers often help adults rear their offspring as can be seen in this table (note primary helpers are relatives whereas secondary helpers are not). At issue is why NONRELATIVES help adults rear offspring. This would clearly seem to be a strategy at odds with the theory of natural selection. Here we show the importance of considering what happens to the nonrelative helper later in its life. Below are data from Reyer (1984).

TABLE 1: Helpers (whether genetically related or not) Increase the Number of Offspring Produced

TYPE OF HELPER	MEAN # HELPERS PER NEST	MEAN # FLEDGLINGS PER NEST	MEAN INCREASE IN # FLEDGED PER HELPER
No Helper	0	1.8	-
Primary Helper	1.0	3.6	1.8
Secondary Helper	1.45	3.7	1.3

Reyer then goes on to show what happens to the helpers in the second year of life. The table below shows the inclusive fitness estimates for male pied kingfishers displaying different behavioral options in their first year and then trying to breed in their second year. These four options are 1) being a primary helper (Prim), 2) being a secondary helper (Sec), 3) breeding in the first year (Breed), and 4) delaying, doing nothing unti the 2nd year (Delay).

Year 1

Year 2

F1 + F2

OPT	y	r	= F1	y	r	s	m	= F2		InF
Prim	1.8	0.32	0.58	2.50	0.50	0.54	0.60	0.41		0.99
Sec	1.3	0.00	0.00	2.50	0.50	0.74	0.91	0.84		0.84
Breed	1.9	0.50	0.95	3.00	0.50	0.59	0.98	0.87		1.82
Delay	0.0	0.00	0.00	2.50	0.50	0.70	0.33	0.29		0.29

Please note that a number of factors must be considered . These include:

y = extra young produced in year 1 (except for breeders); own young produced in year 2

r = coefficient of relatedness between the adult and young

s = probability of survival from year 1 to year 2

m = probability of finding a mate in year 2

F1 = fitness in the first year and F2 = fitness in the second year

QUESTION: What advantage do secondary helpers have by helping nonrelatives? (Hint: Look at the variables contributing to year two fitness and compare secondary helpers with delayers, those that didn't help in year one)