Affiliations:
1University of Tampa, Department of Biology, Tampa,
Florida 33606, USA.
2University of South Florida, Department of
Integrative Biology, Tampa, Florida 33620, USA.
3University of Otago, School of Geography, Dunedin,
9016, New Zealand 46556, USA.
4University of Notre Dame, Notre Dame, Indiana
*Authors contributed equally to this work
Author emails (in order of authorship):tmcmahon@ut.edu,
megan.hill8190@gmail.com,
garrett.lentz@postgrad.otago.ac.nz,
electradoyle93@gmail.com,
nadia.tenouri@postgrad.otago.ac.nz,
jasonrohr@gmail.com
Running Title: Amphibians can learn to avoid Bd
Key words: Chytrid fungus, behavioral resistance, amphibian
decline, chytridiomycosis, disease ecology, disease avoidance,
behavioral avoidance, behavioral ecology, host-parasite interactions,
amphibians
Article type: Letters
Word Count (Abstract): 186
Word Count (main text): 4,696
References: 25
Figures: 5
Tables: 1
Conflicts of interest: No conflicts declared
Author statement : all authors agreed to submission of the
manuscript and accept the responsibility for the accuracy and integrity
of the manuscript.
†To whom correspondence should be addressed. E-mail:
tmcmahon@ut.edu; 813-974-4694
Author contributions: T.A.M. and J.R.R. designed experiments,
T.A.M., M.N.H., G.C.L., E.F.S, and N.F.T. conducted experiments, T.A.M
and J.R.R. conducted statistical analyses. T.A.M, G.C.L., N.F.T. and
J.R.R. wrote the paper, T.A.M, E.F.S., and J.R.R provided funding and
all authors provided editorial advice.
Abstract :
Lethal and sublethal effects of pathogens should theoretically select
for host avoidance of these organisms. Oak toads, for example, learn to
avoid the pathogenic fungus Batrachochytrium dendrobatidis (Bd)
after one infection-clearance event. Here, we investigated whether four
taxonomically distinct amphibians, Cuban treefrogs (Osteopilus
septentrionalis ), southern toads (Bufo terrestris ), greenhouse
frogs (Eleutherodactylus planirostris ), and pine woods treefrogs
(Hyla femoralis ) were also able to learn to avoid Bd and,
if so, what cues they used to identify Bd. Cuban treefrogs, pine woods
treefrogs, and greenhouse frogs did not appear to exhibit detectable
innate or learned avoidance of Bd. However, southern toads learned to
avoid Bd after only one exposure. Southern toads avoided any treatment
containing Bd metabolites but did not avoid treatments that lacked Bd
metabolites even when dead zoospores were present. Bd metabolites
include digestive enzymes that breakdown host tissue and appear to be
the cues that amphibians use to avoid Bd, which is consistent with a
Classical or Pavlovian Conditioning response. It appears that not all
species respond the same way to Bd, which is important information when
developing disease models and conservation plans for amphibians.