| Ecology_-_Displacement_of_Native_Ants Research paper printed in 1999 investigates the causes behind Argentine ant invasions. |
| Facts_about_ants Ant facts: Interesting facts about ants |
| Imported_Fire_Ant Imported Fire ant Information from Purdue University |
| Imported_Fire_Ant Frequently asked questions about Fire Ants from University of Texas. |
| Imported_Fire_Ants Biology of Imported Fire ants and control techniques for lawns and turf from University of Florida Cooperative Extension Service. |
| Imported_Fire_Ants Research and management of the fire ant from Texas Agricultural Experiment Station, Texas Agricultural Extension Service, Texas Department of Agriculture, Texas Tech University,University of Texas, an |
| Japanese_Ants_Color_Image_Database A guide to Japanese ants and their taxonomy, as well as general information about ants. Available in English and Japanese. |
| Lurker\'s_Guide_to_Leafcutter_Ants A guide to the leafcutter ants (Atta, Acromyrmex), including biology, research, care, and images. |
| Myrmecology A comprehensive website about the nature of ants, including pictures and links. |
| Myrmecos_net Close-up images of ants and other insects by Alex Wild. |
| Myrm\'s_Ant_Nest The basics of myrmecology (the study of ants), concentrating on species found in the British Isles. |
| New_World_Army_Ants A review of army ants of the new world. Includes maps and keys. |
| Non-native_ants__Exotic_and_invasive_species A worldwide resource for tracking exotic ants |
| Notes_From_Underground Illustrated articles on ant biology, behavior, and ecology. |
| Online_Catalog_of_Ants_of_North_America Comprehensive resource includes nomenclature (scientific names), natural history, genus-level identification guide, and annotated bibliography. |
| The_Pharaoh_Ant Ohio State University Extension Factsheet on the pharaoh ant, and how it has established itself as a nuisance in hospitals, rest homes, and day care centers. |
| Photos_of_ants Photo encyclopedia of various ants showing their biology and habits. |
| Red_Harvester_Ants Description, pest control, management, and the effect of the diminishing red harvester ant population on the Texas horned lizard which is a protected threatened species. |
| Red_Imported_Fire_Ant History, biology and control of the Red Imported Fire Ant , an IPM pest fact sheet. |
| The_Secret_Life_of_Ants Discusses the architecture of ant nests, the growth of the colony, and the behavior of various species. |
| Smithsonian_Magazine_-_Small_Matters Illustrated article about how leafcutter ants learned to grow fungi. |
| Solenopsis_invicta Imported Fire Ant. |
| USDA_Areawide_Suppression_of_Fire_Ants Information on fire ant control in the USA, including biology, chemical and biological controls, publications, contacts, and distribution maps. |
| White-Footed_Ants Biology, identification and control of white-footed ants. |
| Antipode__A_Radical_Journal_of_Geography Journal information, contents lists and abstracts on the Blackwell Publishing website. |
| Asian_Geographer A journal jointly published by the Hong Kong Geographical Association and the Department of Geography of the University of Hong Kong. |
| Australian_Geographical_Studies Journal of the Institute of Australian Geographers, primarily concerned with the geography of Australia and its neighbouring regions. |
| The_Canadian_Geographer Journal of the Canadian Association of Geographers. |
| Environment_and_Planning__A,B,C_and_D An academic publication with four periodicals covering: planning and design, government and policy and society and space. |
| European_Journal_of_Geography_-_Revue_Européenne_de_Géographie Information, bibliography and news about geography |
| Geopolitics This journal explores the theoretical implications of contemporary geopolitics with a particular reference to territorial problems and issues of state sovereignty. |
| Journal_of_Economic_Geography The aims of the Journal of Economic Geography are to redefine and reinvigorate the intersection between economics and geography, and to provide a world-class journal in the field. |
| Journal_of_Geographic_Information_and_Decision_Analysis A peer-reviewed, scientific journal devoted to the dissemination of current research on geographic information-based decision analysis. |
| The_Pennsylvania_Geographer_Journal Journal of the Pennsylvania Geographic Society. |
| The_Professional_Geographer A Washington D.C. based geography journal. |
| California_Information_Node_of_the_NBII A gateway to information tools for biologists and ecologists, initially emphasizing invasive species management. |
| Ecoinformatics_org An online data and information management resource that aims to produce software, systems, publications, and services that are beneficial to the ecological and environmental sciences. |
| National_Centre_for_Biodiversity_Informatics Disseminates knowledge about Indian biota and its environment. Requires Flash plugin. |
| Dialectology Includes a wealth of general information on dialectology, as well as papers, presentations, links, and information on Dutch dialects. |
| International_Society_for_Dialectology_and_Geolinguistics Committee, membership, and publication information. |
Behavior of real ants
Real ants are capable of finding shortest path from a food source to the nest
(Beckers, Deneubourg and Goss, 1992; Goss, Aron, Deneubourg and Pasteels, 1989)
without using visual cues (Hölldobler and Wilson, 1990).
Also, they are capable of adapting to changes in the environment, for example finding a new
shortest path once the old one is no longer feasible due to a new obstacle
(Beckers, Deneubourg and Goss, 1992; Goss, Aron, Deneubourg and Pasteels, 1989). Consider the following figure in which ants are moving on a straight line which connects a food source to the nest:
It is well-known that the main means used by ants to form and maintain the line is a pheromone trail. Ants deposit a certain amount of pheromone while walking, and each ant probabilistically prefers to follow a direction rich in pheromone rather than a poorer one. This elementary behavior of real ants can be used to explain how they can find the shortest path which reconnects a broken line after the sudden appearance of an unexpected obstacle has interrupted the initial path (see next figure).
In fact, once the obstacle has appeared, those ants which are just in front of the obstacle cannot continue to follow the pheromone trail and therefore they have to choose between turning right or left. In this situation we can expect half the ants to choose to turn right and the other half to turn left. The very same situation can be found on the other side of the obstacle (see next figure).
It is interesting to note that those ants which choose, by chance, the shorter path around the obstacle will more rapidly reconstitute the interrupted pheromone trail compared to those which choose the longer path. Hence, the shorter path will receive a higher amount of pheromone in the time unit and this will in turn cause a higher number of ants to choose the shorter path. Due to this positive feedback (autocatalytic) process, very soon all the ants will choose the shorter path (see next figure).
The most interesting aspect of this autocatalytic process is that finding the shortest path around the obstacle seems to be an emergent property of the interaction between the obstacle shape and ants distributed behavior: Although all ants move at approximately the same speed and deposit a pheromone trail at approximately the same rate, it is a fact that it takes longer to contour obstacles on their longer side than on their shorter side which makes the pheromone trail accumulate quicker on the shorter side. It is the ants preference for higher pheromone trail levels which makes this accumulation still quicker on the shorter path.
References
Beckers R., Deneubourg J.L. and S. Goss (1992). Trails and U-turns in the selection of the shortest path by the ant Lasius niger. Journal of theoretical biology, 159, 397-415.
Goss. S., Aron. S., Deneubourg J.L. and J.M. Pasteels (1989). Self-organized shortcuts in the Argentine ant. Naturwissenschaften 76, 579-581.
Hölldobler B. and E.O. Wilson (1990). The ants. Springer-Verlag, Berlin.
Last modified: November 06, 2006
Web site responsible: Prasanna Balaprakash and Marco A. Montes de Oca
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