10.5061/DRYAD.8PK0P2NNR
Yu, Long
Hubei University
Xu, Xin
Hunan Normal University
Li, Fan
0000-0001-5449-6812
Hubei University
Zhou, Wei
National University of Singapore
Zeng, Hua
Peking University
Tan, Eunice
0000-0003-1667-3958
Yale-NUS College
Zhang, Shichang
Hubei University
Li, Daiqin
0000-0001-8269-7734
National University of Singapore
From crypsis to masquerade: ontogeny changes the colour defences of a crab
spider hiding as bird droppings
Dryad
dataset
2021
FOS: Biological sciences
National Natural Science Foundation of China
https://ror.org/01h0zpd94
31872229
Ministry of Education
https://ror.org/01kcva023
R-154-000-B18-114
National Natural Science Foundation of China
https://ror.org/01h0zpd94
31801979
National Natural Science Foundation of China
https://ror.org/01h0zpd94
32070430
2022-01-05T00:00:00Z
2022-01-05T00:00:00Z
en
https://doi.org/10.5281/zenodo.5814073
21913400 bytes
13
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Selection imposed by visually-hunting predators has driven the evolution
of colour-based antipredator defence strategies such as crypsis,
masquerade, mimicry and aposematism. Individuals of many animals are
generally considered to rely on a single type of defence strategy, but
individuals of some species use multiple colour-based defences. Many
animals switch between colour-based defences against visually-hunting
predators during ontogeny. However, why this occurs remains poorly
understood. The crab spider Phrynarachne ceylonica is an often-cited
example of a bird dropping masquerade. It has recently been demonstrated
that P. ceylonica crab spiders gain protection from their predators by
being misidentified as bird droppings by their predators. P. ceylonica
females show an ontogenetic shift in colour defences: early instars
possess a dark and cryptic form, while at later instars and as adults, the
spiders resemble bird droppings. We hypothesised that this shift may be
driven by differential changes in predation risk of two defence strategies
with increasing body size due to ontogeny. We tested this hypothesis by
presenting naïve domestic chicks with 3D printed artificial spiders of two
different sizes (small, large) and two colours (dark, bird dropping-like),
and determined if larger bird dropping-like spiders are more readily found
and attacked than cryptic forms by chicks. We found that small cryptic
spiders were more difficult to detect than small bird dropping
masquerading spiders, but large cryptic spiders were attacked much more
quickly and more frequently than large bird dropping masquerading spiders.
Increasing predation pressure on larger, cryptic spiders during ontogeny
suggests that switching to bird dropping masquerade may be a more
effective defence as spiders increase in size. We thus conclude that the
ontogenetic shift from crypsis to masquerade is adaptive.