The historical frequency of head-colour morphs in the Gouldian Finch (Erythrura gouldiae)

Date

2009

Authors

Gilby, Amanda J.
Pryke, Sarah
Griffith, Simon C.

Journal Title

Journal ISSN

Volume Title

Publisher

Royal Australasian Ornithologists Union

Abstract

The endangered Gouldian Finch (Erythura gouldiae) possesses a genetic colour polymorphism in the form of three genetically determined head-colours (yellow, black and red) that coexist in the same population. The spatial and temporal pattern of morph ratios within this species provides insight into the selective pressures acting on and maintaining the different forms. To investigate spatial and temporal patterns in the relative historical abundance of the different Gouldian Finch morphs, we surveyed museum collections around the world, identifying 614 wild-caught skins and obtaining accurate data on the morphs of 552 of these. The yellow morph was found at very low numbers (only 15 skins), consistent with its rarity in contemporary populations. Red- and black-morph individuals were found at relatively constant ratios across the geographical range over which they were sampled, and across the 140-year period during which these skins were collected, although this differed slightly for males and females (males: 62.6% black, 37.4% red; females: 79.1% black, 20.9% red). Spatial and temporal stability in the frequency of alternative morphs is extremely rare. These results suggest that the genetic architecture underlying the trait and selective pressures acting on the separate morphs of the Gouldian Finch differ between the sexes, but are fairly constant across highly variable environmental conditions.

Description

Keywords

Keywords: abundance index; bird; coexistence; color morph; environmental conditions; genetic analysis; geographical distribution; population structure; rarity; spatiotemporal analysis; species diversity; surveying; Erythrura gouldiae

Citation

Source

Emu

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1071/MU09013

Restricted until

2037-12-31