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Intraspecific variation in feeding mechanics and bite force in durophagous stingrays
Author(s) -
Kolmann M. A.,
Dean Grubbs R.,
Huber D. R.,
Fisher R.,
Lovejoy N. R.,
Erickson G. M.
Publication year - 2018
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/jzo.12530
Subject(s) - biology , ontogeny , stingray , predation , allometry , juvenile , bite force quotient , omnivore , zoology , marine mammal , ecology , sciaenidae , bay , fishery , oceanography , genetics , fish <actinopterygii> , geology
Animal performance is tightly linked to morphological function, whereby changes in size and performance can influence niche dynamics over ontogeny. To understand how growth affects feeding performance, we examined how bite force over ontogeny differed between two populations of durophagous stingrays, Rhinoptera bonasus (from the Chesapeake Bay and the Florida Gulf Coast, USA ). Cownose stingrays from the Chesapeake Bay specialize on mollusks, whereas Gulf of Mexico stingrays are omnivorous, feeding on a variety of benthic invertebrates. Increases in jaw adductor size resulted in positive bite force allometry across ontogeny in both stingray populations. However, scaling patterns between muscle units differed between the populations, with more drastic increases in bite force over ontogeny in populations feeding on more robust prey. Mechanical testing of the fracture forces of prey suggests that juvenile bivalves are particularly vulnerable to predation by either stingray population. However, Gulf coast stingrays exhibit lower bite forces across ontogeny compared to Chesapeake rays. Chesapeake Bay rays are born larger, further exaggerating the performance disparity between these populations. Although these animals generate considerable bite forces, their ability to comminute bivalves at marketable sizes is doubtful.