Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Consistent with the results of previous studies using poeciliid fish (e.g., Dosen and Montgomerie 2004b; Plath et al. 2008; Wong and McCarthy 2009; Ziege et al. 2009; Jeswiet et al. 2011) and other taxa (e.g., Schwagmeyer and Parker 1990; White and Galef 1999), male guppies here tended to reduce‚Ä¶
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