The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity

In the disease known as annual ryegrass toxicity, galls induced by a nematode, Anguina agrostis, replace seeds in ryegrass (Lolium rigidum) plants. Often these galls are colonised by a bacterium, Corynebacterium rathayi, which makes them toxic and frequently fatal to grazing animals. The ecology of...

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Main Author: Twigg, L.
Format: Report
Published: 1982
Online Access:http://hdl.handle.net/20.500.11937/4854
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author Twigg, L.
author_facet Twigg, L.
author_sort Twigg, L.
building Curtin Institutional Repository
collection Online Access
description In the disease known as annual ryegrass toxicity, galls induced by a nematode, Anguina agrostis, replace seeds in ryegrass (Lolium rigidum) plants. Often these galls are colonised by a bacterium, Corynebacterium rathayi, which makes them toxic and frequently fatal to grazing animals. The ecology of ryegrass pasture ants was studied to determine their role in the epidemiology of this disease. Pitfall traps run over one year in ryegrass pastures revealed nineteen species of ants, all of which foraged maximally between December-March; the period corresponding to that when most seeds and galls are shed. Artificial depots of ryegrass seeds, placed out in pastures, indicated that 22-30% of seeds were removed within 24 hours. The principal ant species taking seed, presented in decreasing order of importance, were Pheidole sp. J.D.M. 155, Pheidole sp. J.D.M. 37, Melophorus sp. 1 (ANIC) and Rhytidoponera inornata. Seed/bacterial gall/nematode gall choice experiments indicated that ants were unselective harvesters of these items. Most seeds were stored around nest entrances, although lesser amounts were retained beneath the soil. Certain species were more prone to store seed than others.
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spelling curtin-20.500.11937-48542019-03-08T10:34:04Z The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity Twigg, L. In the disease known as annual ryegrass toxicity, galls induced by a nematode, Anguina agrostis, replace seeds in ryegrass (Lolium rigidum) plants. Often these galls are colonised by a bacterium, Corynebacterium rathayi, which makes them toxic and frequently fatal to grazing animals. The ecology of ryegrass pasture ants was studied to determine their role in the epidemiology of this disease. Pitfall traps run over one year in ryegrass pastures revealed nineteen species of ants, all of which foraged maximally between December-March; the period corresponding to that when most seeds and galls are shed. Artificial depots of ryegrass seeds, placed out in pastures, indicated that 22-30% of seeds were removed within 24 hours. The principal ant species taking seed, presented in decreasing order of importance, were Pheidole sp. J.D.M. 155, Pheidole sp. J.D.M. 37, Melophorus sp. 1 (ANIC) and Rhytidoponera inornata. Seed/bacterial gall/nematode gall choice experiments indicated that ants were unselective harvesters of these items. Most seeds were stored around nest entrances, although lesser amounts were retained beneath the soil. Certain species were more prone to store seed than others. 1982 Report http://hdl.handle.net/20.500.11937/4854 fulltext
spellingShingle Twigg, L.
The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title_full The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title_fullStr The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title_full_unstemmed The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title_short The Influence of Seed Harvesting Ants in Annual Ryegrass Pastures and Their Possible Effects on the Epidemiology of Ryegrass Toxicity
title_sort influence of seed harvesting ants in annual ryegrass pastures and their possible effects on the epidemiology of ryegrass toxicity
url http://hdl.handle.net/20.500.11937/4854