Interactions between meat ants (Iridomyrmex spadius) and bellyache bush (Jatropha gossypiifolia)

Bebawi, F. F. and Campbell, S. D. (2005) Interactions between meat ants (Iridomyrmex spadius) and bellyache bush (Jatropha gossypiifolia). Australian Journal of Experimental Agriculture, 44 12: 1157-1164. doi:10.1071/ea03194


Author Bebawi, F. F.
Campbell, S. D.
Title Interactions between meat ants (Iridomyrmex spadius) and bellyache bush (Jatropha gossypiifolia)
Formatted title
Interactions between meat ants (Iridomyrmex spadius) and bellyache bush (Jatropha gossypiifolia)
Journal name Australian Journal of Experimental Agriculture   Check publisher's open access policy
ISSN 0816-1089
1836-5787
Publication date 2005-01-24
Sub-type Article (original research)
DOI 10.1071/ea03194
Open Access Status Not yet assessed
Volume 44
Issue 12
Start page 1157
End page 1164
Total pages 8
Place of publication Clayton, VIC, Australia
Publisher C S I R O Publishing
Language eng
Formatted abstract
Understanding the dispersal of weed species is important for the development of effective control strategies. In this study, a series of experiments was conducted to clarify the role that meat ants (Iridomyrmex spadius) play in dispersing bellyache bush (Jatropha gossypiifolia), an exotic shrub currently invading the rangelands of northern Australia. The nutrient composition of food [lipids (fatty acids), fat and soluble carbohydrates] provided by bellyache bush seed components [caruncle, exotegmen and seed (without caruncle and exotegmen)] was identified. Seed components were rich in lipids, particularly palmitic, oleic, stearic, linoleic and eicosenic acids. Oleic and palmitic were most abundant in the caruncle (30% each), linoleic in the seed (61%) and palmitic in the exotegmen (36%). Over all seed components, fat concentration was relatively high (6.3%) compared with soluble carbohydrates (2.3%). The impact of feeding was then determined by comparing germination and viability of intact, non-carunculate (caruncle manually removed) and ant-discarded bellyache bush seeds. Feeding by meat ants significantly increased seed germinability, whilst having no adverse affects on viability. The quantity of seeds dispersed and the seasonal pattern of dispersal was recorded by collecting seed from the middens of randomly selected meat ant nests on a monthly basis. On average, 12 330 ± 603 seeds were retrieved from the middens of individual meat ant nests over 12 months, with highest numbers recorded between February and June (>1200 seeds/ant nest). The effect of this dispersal was determined through comparisons of plant densities within core infestations of bellyache bush, meat ant nest middens and pastures located directly adjacent to core infestations and that were being invaded primarily through localised ballistic dispersal. The density of bellyache bush plants growing from the seed reserves within middens averaged 79 plants/m2, just 18% less than that within core infestations. Seedling survival (1 year) and growth within core infestation and meat ant sites was also quantified. The middens of meat ant nests provided an environment conducive to higher seedling survival and faster growth rates than occurred within core infestations. Mutualistic interaction between bellyache bush and meat ants is likely to build local 'infestation pressure' that may be conducive to range extension in years of exceptionally wet seasons. Management of seed dispersal by meat ants may reduce that risk.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
 
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Created: Fri, 04 May 2018, 16:32:19 EST by Shane Campbell on behalf of Learning and Research Services (UQ Library)