Testing ontogenetic patterns of sexual size dimorphism against expectations of the expensive tissue hypothesis, an intraspecific example using oyster toadfish (Opsanus tau)

Abstract

Trade‐offs associated with sexual size dimorphism (SSD) are well documented across the Tree of Life. However, studies of SSD often do not consider potential investment trade‐offs between metabolically expensive structures under sexual selection and other morphological modules. Based on the expectations of the expensive tissue hypothesis, investment in one metabolically expensive structure should come at the direct cost of investment in another. Here, we examine allometric trends in the ontogeny of oyster toadfish (Opsanus tau) to test whether investment in structures known to have been influenced by strong sexual selection conform to these expectations. Despite recovering clear changes in the ontogeny of a sexually selected trait between males and females, we find no evidence for predicted ontogenetic trade‐offs with metabolically expensive organs. Our results are part of a growing body of work demonstrating that increased investment in one structure does not necessarily drive a wholesale loss of mass in one or more organs.

Relationship between brain size and digestive tract length support the expensive-tissue hypothesis in Feirana quadranus

“…On the contrary, other studies have found no such relationship or even the opposite (Lemaître et al, 2009;Barrickman and Lin, 2010;Navarrete et al, 2011;Liu et al, 2018). The study of Opsanus tau shows that increased investment in one structure does not necessarily drive a loss of mass in one or more organs (Dornburg et al, 2018). Studies in mice have shown that evolutionary increase in cognitive abilities was initially associated with brain plasticity and fueled by an enlarged gut, which was not traded off for brain size, as the ETH posits (Konarzewski et al, 2020).…”