Ammensalism
The “0 / -” symbiotic relationship
What is ammensalism?
• Ammensalism is the ecological
interaction in which an individual
species harms another without
obtaining benefit.
• This type of symbiotic relationship is
common, but not considered an
important process structuring
communities because they are
“accidental” and do not benefit the
species doing the harm
• It is a 0/- relationship
2
Examples of Ammensalism
• Elephants stepping on ants or leveling brush
does not benefit the elephant but causes
harm
Examples of Ammensalism
• Algal blooms can lead to the death of many
species of fish and other animals, however
the algae do not benefit from the deaths of
these individuals
Examples of Ammensalism
• One of the best examples of ammensalism is
the one established between humans and
other species under extinction due to human
actions like habitat devastation by fires,
ecological accidents, pollution of water, etc.
Examples of Ammensalism
• One way scientists have used ammensalism
to help humans can be found in the
relationship of the bread mold penicillium
with bacteria. Penicillium releases a
chemical called penicillin which kills
bacteria without benefiting the bread mold.
Luckily we use this secretion as medicine!
A Summary of Symbiotic Interactions
Influence of Species B
Influence of species A
-
A
- (negative)
0 (neutral/null)
+ (positive)
+
0
+
+
Mutualism
B
A
-
B
Amensalism
A
Parasitism
A
+
B
A
B
0
0
Amensalism
Commensalism
0
-
+
B
A
+
Parasitism
B
+
0
A
B
+
Commensalism
A
+
Mutualism
B