Social homeostasis and foraging efficiency in monogyne Solenopsis invicta (Hymenoptera:Formicidae) societies /
Red imported fire ants are highly successful social insects, accidentally introduced from South America. Reasons given for the success of social insects in general include their ability to homeostatically regulate the effects of resource interruptions within the nest, and exceptional efficiency in...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2001.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726103151&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Red imported fire ants are highly successful social insects, accidentally introduced from South America. Reasons given for the success of social insects in general include their ability to homeostatically regulate the effects of resource interruptions within the nest, and exceptional efficiency in foraging. Solenopsis invicta colonies employ a compensatory response to disruptions in food flow by increasing the number of searchers out in colony territory. Wide spread task switching is a result of colony level food shortages. Experimental manipulations show the proximal cause is the forced change from carbohydrate to lipid metabolism in individual workers. After a 48 to 72 hour period at lower food levels, colonies equilibrated to the new food levels. This was measured both by colony-level scouting intensity and by stores of lipids among individual workers. Colonies self regulated population size to match resource levels. Solenopsis invicta colonies efficiently returned liquid foods from resources as distant as 16-m. Colonies did forage to 32-m, but efficiency as measured by resources being delivered to the colony was significantly lower. Six significant differences were found between fire ants foraging at 32 versus 8 and 16-m distances: 1) Recruits leaving the food at the greatest distance had significantly more load than recruits leaving the food at the shorter distances did. 2) Recruits leaving the food from the greatest distance had significantly less water than ants leaving from the shorter distances. 3) At the greatest distance, recruits approaching the food already had significant loads. 4) Way stations and counter-current food passing was only found on the 32-m recruitment trails. 5) Ants leaving the colony for the 32-m distance were significantly smaller (dry mass) than recruits leaving for the two closer distances. 6) The majorities of recruits returning to the colony from the greatest distance had no detectable sugars, and were also dehydrated. Caste polymorphism and the relative distribution of majors to minors affects the way colonies acquire and process food. Colonies with caste distributions skewed towards the larger sizes were more resistant to starvation, and consumed resources faster, than colonies with caste distributions skewed towards smaller workers. |
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| Item Description: | Vita. "Major Subject: Entomology". |
| Physical Description: | xii, 91 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 85-90). |