Female ornaments revisited– are they correlated with offspring quality?

ByMinyi Chen

4/30/14Bio3102 Ecology Lab

Ornament-fecundity Relationship

• Study of carotenoids-based and other ornamentation

• The resources allocated to ornamentation may reduce the resources available for offspring and thus constrain female fitness

• In turn the ornament-fecundity relationship which may emerge as positive, negative or non-existent

Two Hypothesis

• The ‘direct selection hypothesis’

Female ornaments are under direct sexual selection by males or selection via reproductive competition among females (such as parental care or other non-genetic maternal resources)

Female ornaments honest reflect some aspects of individual quality

• The ‘genetic correlation hypothesis’

Female ornaments signal the genetic quality of individuals

Lande (1980) —— female ornamentation only the first temporal stage of the evolutionary process. After that, the second stage, mutual ornamentation evolves. The last stage, females evolve mechanisms to suppress the expression of their ornament

Two Hypothesis

• genetic correlation hypothesis----Supported by Negative association between the intensity of female carotenoids-based ornamentation and female fitness, able to reallocate carotenoids between different body tissues

• direct selection hypothesis---- supported by Positive association between ornament and offspring quality and thus given stronger, species with no or less reallocation of resources

Association between ornament and egg or offspring quality

54

0

910

31

14

18

20

20

0

5

10

15

20

25

Birds Fishes Lizards Total

Negative

None

Positive

Overview of number of association between ornament and egg- or offspring quality

• Including carotenoids-based and other ornaments than carotenoids-based pooled

• association between female ornaments and different quality and quantity aspects of their eggs and offspring

• Excluding sex-role (male choice and female–female competition) and extra food resources ( experimental)

Taxonomic

groupNegative None Positive

Birds 5 10 18

Fishes 4 3 2

Lizards 0 1 0

Total 9 14 20

Positive relationship

Magellanic Penguin

• Females with larger flippers had a higher probability of raising two chicks (relative to < two chicks)

Scissor-tailed flycatcher

• Female tail length was correlated with early clutch initiation, easy catching insects

Positive relationship-direct selection

Yellow-eyed penguin

• Males can use eye and plumage coloration as an indirect cue in evaluating age and quality of females during mate choice

European shag

• Reproducing females grow larger crest than non-reproducing. Positive relationship—the bigger crest size lead to early reaching egg-laying date. Early breeding is generally associated with high breeding performance

Direct and genetic selection

Northern cardinal

• Redness of female feathers correlated positively with reproductive success, whereas crest and mask were not

Blue-footed booby

• The blue color of the Blue-footed Booby's webbed feet comes from carotenoid pigments

• carotenoid not added (controls): ornamentation was negatively associated with the mass and volume of eggs, but the association was reversed in experiment groups (dietary carotenoids added to feed)

Great tit

• Direct: environmental unfavorable conditions ——low-pathogen-risk, females may not have to allocate so much carotenoids into (immunity) and egg needn’t so much also

• Genetic: environmental unfavorable conditions——great tit chicks of brightly ornamented mothers had lower fledging success compared with chicks of drabber mothers only during

Male generally litter bright

Female

Sockeye salmon(Oncorhynchus nerka)

• Male

Ocean Breeding

• Female (up)

Male (down) • Northern Pacific Ocean, is an carotenoids-rich marine environments for inhabiting

• Juveniles remain in freshwater until they are ready to migrate to the ocean, over distances of up to 1,600 km.

• Sockeye are blue tinged with silver in color while living in the ocean. When they return to spawning grounds, their bodies become red and their heads turn green. Dying after they spawn.

• Females have carotenoids-based ornaments but are not limited by access to carotenoids

Reproductive success in females is determined by the number of eggs she lays, her body size, and the survival of the eggs

Iteroparous & Semelparous

Arctic charr Salvelinus alpinus

• Iteroparous—negetive—genetic

• must trade-off the resource investment during a given breeding season

Sockeye salmon(Oncorhynchus nerka)

• Semelparous—direct

• Less trade-off of ornamentation and investment of carotenoid

Male selection

Zebra finch Taeniopygia guttata

• males prefer to associate with females with bill colors in the middle of the phenotypic range

• Red-billed female died quick because carotenoid means highly immunity. But bright female mean less carotenoid to offspring, less quantity of eggs.

• Genetic based

Male selection

SticklebackGasterosteus aculeatus

• Negative association between red spines and amount of carotenoids in eggs

• prefer females with drab spines

Thanks