Authors: James H Bandoli
Publish Date: 2005/10/25
Volume: 59, Issue: 5, Pages: 606-613
Abstract
Filial cannibalism is hypothesized to allow nestguarding males to recoup energy lost during nest defense Males in many species of fishes occasionally defend broods containing both sired and foster eggs due to shifts in nest site ownership or cuckoldry Such males are predicted to consume primarily foster eggs if the ability to discriminate among eggs exists In a previous laboratory study male spottail darters Etheostoma squamiceps consumed significantly more foster eggs than sired eggs suggesting the existence of a mechanism for discrimination using chemical or positional cues This discrimination mechanism in the spottail darter was tested by creating nest sites with half sired eggs and half foster eggs n=15 or with all sired eggs with half positionally relocated n=9 Males defended these nests for 2 days in the field and cannibalism was determined by counting eggs lost during that interval Neither foster eggs nor relocated sired eggs were consumed in greater numbers or percentages of the original brood sizes than the unchanged sired eggs indicating that male spottail darters do not discriminate between foster and sired eggs by olfaction or position Alternatively the hypothesis that males treat all eggs in nest sites in which they have spawned as sired explains the results of both studiesT Hayes A Jackson M Walls and S Loveless provided valuable assistance in the field experiments B Wilding provided statistical advice Comments by three anonymous reviewers greatly improved an earlier version of this manuscript Partial funding for this research was provided by a grant from the Indiana Academy of Science This research was conducted with approval from the University of Southern Indiana Institutional Animal Care and Use Committee permit no 101
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