Premium
Transient Competitive Displacement in Natural Populations of Wirligig Beetles
Author(s) -
Istock Conrad
Publication year - 1967
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934536
Subject(s) - character displacement , competition (biology) , displacement (psychology) , ecology , environmental science , biology , habitat , sympatry , psychology , psychotherapist
A transient competitive displacement of Dineutes nigrior by D. horni was observed in a northern Michigan pond, and the uniform rate of displacement during one larval generation was estimated. The estimate agreed well with rates obtained in laboratory experiments with the same species. It would be difficult to account for the displacement without assuming competition. These species probably came into competition in Michigan as their ranges extended northward after the last glacial recession. The rate of displacement per generation measured here for Dineutes is larger than estimates from data for Aphytis presented by DeBach and Sundby (1963). Despite lower rates of local displacement there have been very rapid geographical displacements among Aphytis species, presumably because of the simplicity and regularity of the citrus grove communities where these species have been introduced. Competitive displacement and competitive coexistence are simply the results of high and low rates of displacement. However, competitive displacement leads to species sorting in the development of communities, whereas competitive coexistence may contribute to community stability and, if prolonged, leads to finely diversifying evolution.