DECORATING BEHAVIOR OF MAJOID CRAB, CAMPOSCIA RETUSA, DOES NOT FACILITATE THE VISUALLY CRYPTIC CAMOUFLAGE STRATEGY OF BACKGROUND COLOR MATCHING
Date
2020-05
Authors
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Publisher
University of Delaware
Abstract
Camouflage conceals an organism through the prevention of detection and/or
recognition; and understanding the mechanisms behind various camouflage strategies
is vital. As camouflage strategies target the perception of a specific predator or prey
species, strategies need to be defined with these intended targets in mind. A species’
inherent coloring or markings, habitat choice, and/or decorating behavior could
facilitate a specific camouflage strategy. A species exhibiting decorating behavior
deliberately accumulates and retains environmental material on the exterior of its
body. Some of the most well-known decorators in the animal kingdom are the spider
crabs of the Majoidea superfamily. Camposcia retusa is a coral reef-dwelling Majoid
species that exhibits decorating behavior. However, the sensory modalities utilized by
this species in the selection of decoration material remains unknown. It was
hypothesized that C. retusa’s decorating behavior facilitates the cryptic camouflage
strategy of background color matching. If so, C. retusa should be able to (1) select
decoration materials that match the color of its background, and (2) detect the color of
its previously attached decorations and choose a habitat in a similar background color.
Through a set of laboratory-based behavioral choice experiments, I show that C.
retusa’s decorating behavior does not facilitate background color matching. When
placed in a consistent background (either black or white), no statistical difference was
found in the color of craft pompoms selected. Additionally, when pre-decorated with
craft pompoms of a specific color, crabs did not select a habitat to match the pompoms
previously attached to their exterior. Further, no statistical difference was found in the
pompom color selection when crabs were allowed to decorate in the absence of light
compared to when light was present. While this study focused on one camouflage
strategy, background color matching, C. retusa may be utilizing a number of other
camouflage and non-camouflage strategies aimed at impacting the visual or non-visual
sensory systems of its predators.
Description
Keywords
marine science, decorator crab, camouflage