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Against Bergmann’s rule: fly sperm size increases with temperature
Author(s) -
Blanckenhorn Wolf U.,
Hellriegel Barbara
Publication year - 2002
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1046/j.1461-0248.2002.00298.x
Subject(s) - bergmann's rule , biology , generality , sperm , ecology , zoology , mechanism (biology) , evolutionary biology , genetics , epistemology , psychology , geography , philosophy , geodesy , latitude , psychotherapist
A long‐standing school textbook biological rule, Bergmann’s rule, asserts that animals (and their constituent parts) grow bigger when it is colder. This seems to hold for many warm‐blooded animals, as well as for egg, cell and body size of most cold‐blooded animals. A unifying mechanism producing this pattern has not been found. We here provide the first experimental evidence that the size of an important type of cell, namely sperm, increases (rather than decreases) with temperature in a cold‐blooded animal, the yellow dung fly. By pointing to an exception, our work either questions the generality of one prominent category of explanation of Bergmann’s rule, that of a physiological constraint, or alternatively suggests that sperm differ fundamentally in their physiology from other cells.