Reproductive biology of Corymbia citriodora subsp variegata and effective pollination across its native range in Queensland, Australia

Bacles, CFE, Brooks, J, Lee, DJ, Schenk, PM, Lowe, AJ and Kremer, A (2009) Reproductive biology of Corymbia citriodora subsp variegata and effective pollination across its native range in Queensland, Australia. SOUTHERN FORESTS, 71 2: 125-132. doi:10.2989/SF.2009.71.2.7.822


Author Bacles, CFE
Brooks, J
Lee, DJ
Schenk, PM
Lowe, AJ
Kremer, A
Title Reproductive biology of Corymbia citriodora subsp variegata and effective pollination across its native range in Queensland, Australia
Formatted title
Reproductive biology of Corymbia citriodora subsp variegata and effective pollination across its native range in Queensland, Australia
Journal name SOUTHERN FORESTS   Check publisher's open access policy
ISSN 2070-2620
Publication date 2009-06-01
Year available 2009
Sub-type Article (original research)
DOI 10.2989/SF.2009.71.2.7.822
Open Access Status
Volume 71
Issue 2
Start page 125
End page 132
Total pages 7
Editor Owen, D.
Place of publication South Africa
Publisher Southern African Institute of Forestry
Language eng
Subject 829899 Environmentally Sustainable Plant Production not elsewhere classified
060705 Plant Physiology
C1
Abstract The spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora subsp. variegata (CCV) is widespread in south-eastern Queensland and northern New South Wales. It is currently the most commonly harvested native hardwood in Queensland. However, little basic knowledge of the reproductive biology of the species is available to inform genetic improvement and resource management programmes. Here we take an integrative approach, using both field and molecular data, to identify ecological factors important to mating patterns in native populations of CCV. Field observation of pollinator visitation and flowering phenology of 20 trees showed that foraging behaviour of pollinator guilds varies depending on flowering phenology and canopy structure. A positive effect of tree mean flowering effort was found on insect visitation, while bat visitation was predicted by tree height and by the number of trees simultaneously bearing flowers. Moreover, introduced honeybees were observed frequently, performing 73% of detected flower visits. Conversely, nectar-feeding birds and mammals were observed sporadically with lorikeets and honeyeaters each contributing to 11% of visits. Fruit bats, represented solely by the grey-headed flying fox, performed less than 2% of visits. Genotyping at six microsatellite markers in 301 seeds from 17 families sampled from four of Queensland's native forests showed that CCV displays a mixed-mating system that is mostly outcrossing (t(m) = 0.899 +/- 0.021). Preferential effective pollination from near-neighbours was detected by means of maximum-likelihood paternity analysis with up to 16% of reproduction events resulting from selfing. Forty to 48% of fertilising pollen was also carried from longer distance (>60 m). Marked differences in foraging behaviour and visitation frequency between observed pollinator guilds suggests that the observed dichotomy of effective pollen movement in spotted gums may be due to frequent visit from introduced honeybees favouring geitonogamy and sporadic visits from honeyeaters and fruit bats resulting in potential long-distance pollinations.
Formatted abstract
The spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the
east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora
subsp. variegata (CCV) is widespread in south-eastern Queensland and northern New South Wales. It is currently the most
commonly harvested native hardwood in Queensland. However, little basic knowledge of the reproductive biology of the
species is available to inform genetic improvement and resource management programmes. Here we take an integrative
approach, using both field and molecular data, to identify ecological factors important to mating patterns in native populations
of CCV. Field observation of pollinator visitation and flowering phenology of 20 trees showed that foraging behaviour of
pollinator guilds varies depending on flowering phenology and canopy structure. A positive effect of tree mean flowering effort
was found on insect visitation, while bat visitation was predicted by tree height and by the number of trees simultaneously
bearing flowers. Moreover, introduced honeybees were observed frequently, performing 73% of detected flower visits.
Conversely, nectar-feeding birds and mammals were observed sporadically with lorikeets and honeyeaters each contributing
to 11% of visits. Fruit bats, represented solely by the grey-headed flying fox, performed less than 2% of visits. Genotyping
at six microsatellite markers in 301 seeds from 17 families sampled from four of Queensland’s native forests showed that
CCV displays a mixed-mating system that is mostly outcrossing (tm = 0.899 ± 0.021). Preferential effective pollination from
near-neighbours was detected by means of maximum-likelihood paternity analysis with up to 16% of reproduction events
resulting from selfing. Forty to 48% of fertilising pollen was also carried from longer distance (>60 m). Marked differences
in foraging behaviour and visitation frequency between observed pollinator guilds suggests that the observed dichotomy of
effective pollen movement in spotted gums may be due to frequent visit from introduced honeybees favouring geitonogamy
and sporadic visits from honeyeaters and fruit bats resulting in potential long-distance pollinations.
Keyword contemporary gene flow
NEW-SOUTH-WALES
Corymbia
Eucalypt
mating system
pollinator visitation
reproductive biology
spotted gums
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID 009114 2005-2008
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Biological Sciences Publications
 
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Created: Thu, 03 Sep 2009, 17:46:48 EST by Mr Andrew Martlew on behalf of School of Biological Sciences