4.2 Sex-related dietary specialization
While many previous studies have observed differences in foraging
behavior and invertebrate prey selection between sexes in western
sandpipers, we report the first observation of differences in biofilm
and microphytobenthos consumption between sexes (Fernández & Lank,
2008; Mathot & Elner, 2004; Mathot, Lund, & Elner, 2010; Nebel, 2005).
Our results indicated that consumption of microphytobenthos increased
and consumption of Polychaeta decreased with decreasing bill length in
western sandpipers. We also found that the consumption of other
invertebrates – a prey group predominantly composed of epifaunal
invertebrates in the classes Malacostraca and Gastropoda – increased
with decreasing body mass. Male western sandpipers have shorter bills
and lesser mass than their female counterparts which may make males
better adapted, both mechanically and energetically, to consume biofilm,
microphytobenthos, and invertebrates on the sediment surface (Elner et
al., 2005; Nebel, Jackson, & Elner, 2005; Sutherland et al., 2000). In
contrast, females, with their longer bills, may be better adapted to
probe for submerged invertebrates including Polychaeta (Nebel et al.,
2005; Sutherland et al., 2000).