Lecture 5: dunnock and alpine accentor

Question 1

who studied dunnocks:

Answer 1

Nick Davies in Cambridge 1980

Question 2

dunnock’s mating system

Answer 2

v variable:

• monogamy
• polygyny
• polygynandry
• polyandry

Question 3

polygynandry

Answer 3

multiple females looked after by multiple males

Question 4

mean female territory sizes in monogamous, polygynous and polyandrous

Answer 4

mono & polygyny = 0.25ha
polyandry = 0.55 ha
–> F range size drives variation in mating system

Question 5

Female _____ drives variation in mating system

Answer 5

range size

Question 6

experiment to see food resource on f & m territory sizes and mating systems

Answer 6

food available = female = smaller territories
male territories unaffected

-when female territories large sig more polyandry occurring

Question 7

alpine accentor live?

Answer 7

above 2000m

Question 8

alpine accentor mating system =

Answer 8

polygynandrous

-typical 3 females and 3 males in one territory (alpha, beta and gamma male)

Question 9

alpine accentors vs dunnocks territory ranges

Answer 9

dunnocks = 0.2-1 ha female and 0.2-2ha male

aa = 6- 30 ha females and 9- 38ha males

aa a lot bigger! as their habitat = temporal unpredictability
- larger habitat = sure of access to resources

Question 10

Variation within & between species depends on the distribution of resources which in turn determines ___ dispersion which determines ___ dispersion

Answer 10

Female then male

Question 11

Accentor breeding biology:

Answer 11

• female builds nest
• lay 3-5 blue eggs
• F incubates
• both sexes feed chicks & fledglings
• pair often have 2 broods her year

Question 12

monogamy in dunnocks

Answer 12

• M guards F
• F solicits (exposes cloaca)
• M pecks cloaca, female ejects sperm from earlier matings
• copulate 1-2 times per hour
• male monopolises matings –> 100% paternity
• males share chick feeding equally w the female

Question 13

polygyny in dunnocks

Answer 13

• males guard and copulate with 2 females
• M either invest in brood of one F but not the other, or they divide their investment
• f fertility staggered, they’re ok
• if f fertility at same time, hard work for M
• f get reduced assistance in looking after chicks

Question 14

polyandry in dunnocks

Answer 14

• M compete to copulate
• • alpha M gets most
• • f male sneak off with beta M

M parental care varies

• • alpha males always care
• -beta male sometimes do nothing, but may work as hard as alpha-male, more likely to feed young if they have paternity
• in polyandry, paternity is often shared between males

Question 15

polyandrous dunnock experiment

Answer 15

• 28 alpha males removed from territory
• beta males allowed to mate w females
• beta males showed more care (feeding)

Question 16

alpine accentors; parental investment is related to

Answer 16

mating access

–more time spent mating w female, more chance they’ll help feed brood

Question 17

Accentor breeding biology:

Answer 17

• -Males compete to mate w females
• -variable mating success reflected in paternity
• • variable male paternity care explained by paternity

Question 18

Dunnocks competition among females:

Answer 18

Fighting between females 
-loser often deserts eggs
--highest in polygyny (39%) as females competing 
-monogamy 20%
polyandry 8%

Question 19

In dunnocks polyandry: Female should copulate with ___ in her group to gain their parental investment

Answer 19

both males, should aim for 50:50 share of matings with alpha & beta

Question 20

F behaviour in alpine accentor

Answer 20

• to convince males they have some paternity females copulate up to 1000 / clutch
• males have huge testes (8% body weight) and a large cloacal protuberance
• females solicit with bright red cloaca
• Females compete by singing

Question 21

Dunnock reproductive succes:

Answer 21

more male help by male reduces starvation and means more fledglings can be produced

Question 22

Alpine accentor reproductive success

Answer 22

more care provided by males, the better the condition of chicks when they fledge

Question 23

Male reproductive success different mating systems in dunnocks

Answer 23

polygyny is highest, monogamy then polyandry (alpha then beta)

Question 24

Female reproductive success different mating systems in dunnocks

Answer 24

polyandry is highest, monogamy then polygyny

Question 25

males compete for __ and females compete for ___ care

Answer 25

matings & paternal care