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Foreword
- Edited by Jenni A. Stockan, Elva J. H. Robinson, University of York
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- Book:
- Wood Ant Ecology and Conservation
- Published online:
- 05 June 2016
- Print publication:
- 07 July 2016, pp xiii-xiv
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Summary
Ants are everywhere. They are dominant components in much of the terrestrial world as premier soil turners, predators of other arthropods, dispersers of seeds and, in neotropical regions, the attine leafcutter ants must be considered the major herbivores in rainforests and cultivated fields. Approximately 14 000 species of ants are known to science, but the number continues to grow and it is hard to say how many species actually live on our planet.
Science has revealed many unique and fascinating natural histories for a large diversity of ant species, but certain groups stand out. Clearly, the pinnacles in ant evolution include the army ants of the neotropics and the driver ants of Africa, the tree-dwelling weaver ants of Africa, Asia and Australia, the fungus growers of the tribe Attini in Central and South America, and the migrating herdsmen of the genus Dolichoderus of the Malaysian peninsula. The mound-building wood ants, the so-called Formica rufa group, must also be considered one of the pinnacles of ant evolution.
In 1960, as an advanced biology student at the University of Würzburg in Germany, I was charged with the wonderful task of spending about 2 months in Finland collecting wood ants in forests from the south to the north beyond the Arctic Circle to send these samples to the Institute of Applied Zoology at the University of Würzburg. The general abundance of Formica mounds in Finnish forests, especially in primeval forests, was most impressive. Unfortunately, wood ant mounds are now rare or totally absent in most Central European forests mostly due to negligence, despite the fact that entomologists had already recognised in the nineteenth century the decisive role wood ants play in biological pest control. The undisputed founder of forest entomology, Julius Theodor Christian Ratzeburg (1801–71), observed that the surrounds of wood ant mounds resembled green islands during pest insect outbreaks. According to Auguste Forel (1848–1931) the inhabitants of a single large Formica rufa nest can retrieve 100 000 insects in one day; this adds up to 10 million prey insects in one summer. These numbers are astonishing and perhaps somewhat exaggerated, or perhaps not? In any case, mound-building wood ants are very beneficial to the health of forests, and therefore Ratzeburg proposed to propagate and resettle Formica nests by artificial fission.
Profile: Multi-component signals in ant communication
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- By Bert Hölldobler, Arizona State University, Tempe, Arizona, USA
- Edited by Tamás Székely, University of Bath, Allen J. Moore, University of Exeter, Jan Komdeur, Rijksuniversiteit Groningen, The Netherlands
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- Book:
- Social Behaviour
- Published online:
- 05 June 2012
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- 18 November 2010, pp 127-131
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Summary
What the fruit fly is for classical genetics and the squid axon for neurobiology, the insect society is for experimental sociobiology. Many of the sociobiological concepts and hypotheses proposed more than 40 years ago were confirmed, modified, revised or advanced by empirical studies with social insects during the past quarter-century.
The remarkable ecological success of social insects, and in particular of ants, is largely based on two key features of insect societies: cooperation and communication. In fact, a central element of any social behaviour is communication (see Chapter 8). The study of communication behaviour is at the core of any attempt to analyse social organisations. Without communication, social interactions and cooperation of any kind are impossible, be they interactions between genes in a genome, between organelles inside a cell, interactions of cells and organs in organisms, or cooperation among individuals in societies.
From early on in my scientific career I was interested in decoding communication mechanisms in social insects, particularly in ants, and I was fascinated by the comparative exploration of the evolutionary origin, function, diversity and complexity of social systems. I was, and continue to be, intrigued by the universal observation that wherever social life in groups evolved on this planet, we encounter (with only a few exceptions) a striking correlation: the more tightly organised within-group cooperation and cohesion, the stronger the between-group discrimination and hostility.
Annual foraging of the leaf-cutting ant Atta colombica in a semideciduous rain forest in Panama
- Rainer Wirth, Wolfram Beyschlag, Ronald J. Ryel, Bert Hölldobler
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- Journal:
- Journal of Tropical Ecology / Volume 13 / Issue 5 / September 1997
- Published online by Cambridge University Press:
- 10 July 2009, pp. 741-757
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In a 1-y study of vegetation harvested by the leaf-cutting ants, Atta colombica Guérin, daily harvesting activity of two nests was observed for 24 h at c. 1-wk intervals (colony I: June 1993-June 1994; colony II: February-June 1994) on Barro Colorado Island. The average daily quantity of green leaves harvested by colony I was higher during the wet season (11.4 m2 d−1) than during the dry season (9.0 m2 d−1), but was highly variable between survey days. Total annual herbivory of green leaves was estimated to be 3,855 m2 foliage area for colony I and 1,707 m2 for colony II. Total dry weight of biomass harvested was higher in the dry season because most material collected during the wet season consisted of green leaves, while during the dry season, more than 50% of the total collected biomass was non-green plant material (stipules of Ficus sp., fruits, seeds, and flower parts of a variety of other species) which represented c. one third (111 kg y−1) of the total annual intake (370 kg y−1) of plant material. Total daily biomass intake was negatively correlated with daytime rainfall. The peak of daily foraging was affected by timing and duration of rainfall events. Highest input rates normally occurred between 15:00 and 16:00 h (colony I).Dry weight and surface area of harvested leaf fragments differed between plant species, with thicker leaves generally being cut into smaller pieces. Significant linear correlations were found between total daily harvest of fragments and the respective harvesting rate at the maximum of daily activity. High correspondence was found between estimates using this relationship and the measured daily leaf harvest of four other Atta colonies and of two colonies reported in published literature. The use of this relationship as a research tool is discussed.
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