Description
This programme examines the symbiotic relationship between ants (Pseudomyrex belti) and acacias (Acacia cornigera).
Metadata describing this Open University video programme
Module code and title: S323, Ecology
Item code: S323; 11
First transmission date: 23-07-1974
Published: 1974
Rights Statement:
Restrictions on use:
Duration: 00:22:53
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Producer: Neil Cleminson
Contributor: Dan Janzen
Publisher: BBC Open University
Keyword(s): Defence mechanism; Inter-relationships; Lipids; Mutualistic & obligate relationship; Organism; Sugars
Footage description: Dan Janzen introduces the programme which will examine their relationship between ants (Pseudomyrex belti) and swollen thorn acacias (Acacia cornigera). To aid his discussion he has with him in the studio a young acacia plant and a map of central America where the plant and ants are found. Janzen points out the habitat of the acacia on the map. Shots of the hot lowlands of Central America and shots of acacia plants. Janzen explains what the acacia plant does for the ants which live on it. Shots of acacia thorns which provide the ants with nests. Shots of food bodies on the tips of leaves which provide the ants with protein, lipids and vitamins. Shots of nectar droplets on leaves which provide the ants with sugar. Shots of acacia plants. Janzen explains that the acacia stays green throughout the dry season so providing the ants with food the year around. Janzen, with a young acacia plant in the studio, explains what the ant does for the acacia plant. He explains that the ants clean away competing plants. Shots of bindweed and acacia plant. Janzen then explains that ants attack other animals which attack the plant. Shots of ant worker attacking Janzen's hand. Janzen explains how ants establish new colonies on acacias. Diagrams and still shots of a queen and male ant aid his discussion. Shots of a fertilised queen making a nest in an acacia thorn. Shots of an ant colony at the entrance to the thorn nest. Janzen explains the technique he used to get an ant colony to the studio and established on a young acacia Shot of ants on a young acacia plant in the studio. Janzen opens a thorn to expose a queen, her eggs and her brood. Shots of the queen with her eggs and brood. Janzen discusses an experiment which was set up to determine the effect of an ant colony on the acacia plant. Two groups of acacias were cut down and the ant colony from one was killed. Sucker growth was examined on both after 45 days and again after 9 months. The difference in growth rate as seen on both occasions is very striking. Janzen next examines cases of animals which inhabit acacias plants and have found solutions to attacks by the ants. He discusses first nest building birds. Janzen next discusses the case of moths who deposit their eggs on the underside of acacia leaves. The moth larvae take on the ant colony odour and are not molested by the ants. Shots of moth and its caterpillar. Janzen then discusses a third example - a caterpillar which finds an empty ant nest and spins a web over the entrance to keep out the ants. Shots of the caterpillar. Janzen explains why the acacia is a good plant to use when studying defensive systems of plants in general. Credits over film shots of ants at the entrance to their nest.
Master spool number: 6HT/71316
Production number: 00525_1130
Videofinder number: 1035
Available to public: yes