Resistance to crushing from wave-borne debris in the barnacleBalanus glandula

Abstract

Abstract. Barnacles of the same species (Balanus glandula) show differences both in shell morphology and in their ability to resist crushing from impact at two sites within 8 km of each other which differ in their natural exposure to wave-borne debris (Cattle Point and False Bay, San Juan Island, Washington, USA). In studies performed in 1987, barnacles with shells of a given base diameter at the site exposed to more impact (Cattle Point) were found to have smaller bodies, shorter and thicker shells, and a more protected placement of their opercular valves than barnacles at the protected site. When tested with a standard impact, barnacles from the exposed site were more resistant to crushing both on the first impact and (for those surviving that test) on a second impact 2 wk later. The morphological differences between the two populations may be due to a combination of different shell:body growth rate ratios at the two sites plus passive remodelling of the exposed barnacles by small impacts. The morphological changes at the exposed site, although gained passively, fortuitously provide improved performance in resisting crushing from impact.

Ritualized fighting and biological armor: the impact mechanics of the mantis shrimp's telson

“…Analyzing impact in terms of the coefficient of restitution provides a significant advancement over methods previously used by biologists, which were limited to determining the amount of impact energy necessary to break a structure (Barnes et al, 1970;Pentcheff, 1991;Shanks and Wright, 1986;Strathmann, 1981). Breaking strength is not necessarily the most relevant material property, particularly given that many animals operate with significant safety factors (Biewener, 2003;Hahn and LaBarbera, 1993).…”

“…Dropping weights on barnacles led Shanks and Wright (Shanks and Wright, 1986) to demonstrate that breaking strength and shell fracture patterns were species specific, and that aggregations of barnacles were more resistant to impact than solitary animals. This same method allowed other authors to determine that barnacle species living in areas exposed to waveborne debris are less prone to damage from impacts than species living in protected areas (Barnes et al, 1970;Pentcheff, 1991). In addition to these few invertebrate examples, bone impact mechanics have been studied extensively (e.g.…”

Epibiosis in Crustacea: an overview

“…In one study, barnacles were the only representatives of macrofauna on free-living crabs, whereas confined specimens were also colonized by soft-bodied hydrozoans and ascidians. Barnacles are known to resist considerable mechanical stress, such as wave action as well as wave-borne fragments of hard materials (Pentcheff, 1991).…”

Adaptive Plasticity of the Penis in a Simultaneous Hermaphrodite

“…Because avoiding waves is not always possible, barnacles have developed several morphological solutions to the risks imposed by wave impacts. Barnacles build shells that are more resistant to being crushed by debris in wave‐exposed areas (Pentcheff 1991), the feeding cirri of barnacles change size and shape dramatically in response to wave exposure (Arsenault et al 2001; Marchinko 2003), as do their penises (Hoch 2008; Neufeld and Palmer 2008). In the case of the penis, the functional advantage of one exposure‐specific morphology over another has yet to be explained.…”