Reproductive Traits and Hatchling Characteristics of the Endemic Sardinian Grass Snake (Natrix helvetica cetti): First Field Data, with Screening for Ophidiomyces ophidiicola
Animals,
Journal Year:
2025,
Volume and Issue:
15(3), P. 418 - 418
Published: Feb. 3, 2025
The
Sardinian
grass
snake,
Natrix
helvetica
cetti,
is
an
island-endemic
subspecies
with
a
restricted
and
highly
fragmented
distribution
confined
to
Sardinia,
Italy.
Information
on
its
reproductive
biology
wild
offspring
remain
scarce
in
the
scientific
literature.
This
present
study
reports
first
recorded
data
clutch
of
eggs
laid
by
melanistic
female
N.
h.
cetti
that
exhibited
lethargy
when
observed
basking,
prompting
brief
period
health
monitoring
screening
for
presence
pathogenic
fungus
Ophidiomyces
ophidiicola
(Oo).
yielded
nine
hatchlings,
which
phenotypic
are
provided
compared
existing
information
natrix
complex.
Both
adult
tested
negative
Oo
screening.
body
size
specifically
snout-to-vent
length
48.3
cm,
smallest
ever
gravid
helvetica.
may
indicate
maturity
reached
at
particularly
small
sizes,
distinctive
trait
this
intriguing
island
subspecies,
suggesting
need
further
investigation.
Language: Английский
Using Snake Roadkill Patterns to Indicate Effects of Climate Change on Snakes in Taiwan
Sustainability,
Journal Year:
2025,
Volume and Issue:
17(4), P. 1580 - 1580
Published: Feb. 14, 2025
This
study
investigates
the
impacts
of
climate
change
on
snake
behavior
and
distribution
in
Taiwan
by
analyzing
roadkill
data
from
Roadkill
Observation
Network
(TaiRON).
Focusing
2012
to
2019,
analysis
reveals
temporal
spatial
changes
patterns,
shedding
light
ecological
effects
a
warming
climate.
From
number
events
exhibited
rising
trend,
particularly
during
peak
activity
months
May
October,
which
accounted
for
over
70%
annual
cases.
However,
notable
increase
was
observed
January,
traditionally
low-activity
period,
with
numbers
14.9-fold
proportions
increasing
nearly
6-fold
period.
shift
suggests
that
warmer
winters
are
extending
active
period
snakes,
potentially
altering
their
seasonal
behaviors.
Spatially,
showed
northward
upward
migration,
reflecting
response
temperatures
habitat
shifts
higher-altitude
regions.
These
migratory
trends,
while
adaptive,
expose
snakes
heightened
risks
newly
occupied
habitats.
The
findings
underscore
potential
as
robust
monitoring
tool
understanding
species
responses
change.
By
integrating
citizen
science
analyses,
this
research
highlights
critical
role
environmental
driving
shifts.
emphasizes
need
climate-adaptive
conservation
strategies,
including
road
design
improvements
biodiversity-focused
policies,
mitigate
safeguard
populations.
insights
contribute
broader
efforts
formulation
evidence-based
policies
address
cold-blooded
animals.
Language: Английский
Environmental Gradients in Lizard Colouration
Ecology and Evolution,
Journal Year:
2025,
Volume and Issue:
15(3)
Published: Feb. 28, 2025
ABSTRACT
Environmental
pressures
shape
animal
colouration,
facilitating
adaptation
to
local
conditions.
However,
the
extent
which
climatic
gradients
drive
colour
variation
in
a
species
across
its
distributional
range
remains
unclear.
Here,
we
tested
whether
dorsal
colouration
of
Lusitanian
wall
lizards
(
Podarcis
lusitanicus
)
varies
spatially
response
environmental
distribution
north‐western
Iberian
Peninsula.
We
estimated
brightness
(i.e.,
lightness)
from
multispectral
photographs
463
animals,
originating
21
locations
distributed
range.
studied
direct
and
indirect
(mediated
by
body
mass)
relationships
between
variables
lightness
lizards,
piecewise
structural
equation
modelling.
simultaneously
predictions
Gloger's
(darker
warm
humid
environments),
thermal
melanism
colder
photoprotection
areas
with
higher
intensity
solar
radiation)
Bergmann's
(larger
size
environments)
hypotheses.
found
that
best
follows
hypothesis
for
humidity,
but
not
supporting
hypothesis,
independent
populations'
shared
ancestry
geographic
location.
no
support
melanism,
as
temperature
was
directly
associated
lightness.
Instead,
effect
on
through
detected.
Consistent
regions
tended
be
larger
darker.
Our
study
indicates
evolution
lizard
is
driven
variable
factors.
Experimental
tests
are
necessary
assess
mechanisms
driving
effects
diverse
environments,
advancing
beyond
simplistic
correlations
suggested
ecogeographic
Language: Английский
Habitat openness and squamate color evolution over deep time
Nature Communications,
Journal Year:
2025,
Volume and Issue:
16(1)
Published: March 17, 2025
Abstract
While
the
ecological
roles
of
colored
integument
have
been
extensively
studied,
what
regulates
global
patterns
color
variation
remains
poorly
understood.
Here,
using
a
dataset
1249
squamates,
we
evaluate
whether
and
how
six
key
eco-environmental
variables
their
interactions
shaped
evolutionary
history
coloration.
We
show
that
only
habitat
openness
consistently
associates
with
brightness
evolution,
brighter
integuments
favored
in
open
habitats,
possibly
for
enhanced
heat
reflection.
Furthermore,
evolution
rates
likely
track
δ
18
O
(a
temperature
proxy)
changes
increase
during
aridification
phases,
such
as
those
Miocene
Pliocene.
This
trend
may
be
due
to
establishment
an
arid
climate
promoted
shifts,
ultimately
inducing
adaption
new
niches.
Our
findings
suggest
single
environmental
variable
is
associated
largest
extant
tetrapod
order.
Language: Английский
A comparative phylogenetic approach for the evolution of melanism in elapid snakes supports the Bogert's rule
Journal of Zoology,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 24, 2025
Abstract
Melanism
is
a
common
trait
in
vertebrates.
While
endotherms,
melanism
has
been
primarily
associated
with
the
protection
against
oxidative
stress
caused
by
incoming
UV
radiation,
ectotherms,
it
far
less
understood.
Bogert's
rule,
most
widely
supported
biogeographical
framework
explaining
occurrence
of
reptiles,
states
that
melanistic
individuals
should
be
favoured
thanks
to
faster
heating
rates.
It
led
formulation
Thermal
Hypothesis
explain
evolution
and
maintenance
ectotherms.
Although
some
support
for
this
hypothesis
exists,
not
broadly
accepted,
importance
thermal
advantage
as
an
evolutionary
driver
ectotherms
needs
specifically
addressed.
squamate
where
occurs
at
various
extents
depending
on
considered
taxonomic
level.
Such
variability
opens
use
phylogenetic
comparative
approach
test
whether
climatic
conditions,
pivoting
advantage,
could
drive
reptiles.
By
focusing
snake
family
Elapidae,
we
firstly
reconstructed
history
and,
subsequently,
tested
climate
affects
frequency
melanism.
Ancestral
state
reconstruction
estimated
ability
express
ancestral
condition
elapid
snakes.
Furthermore,
found
statistically
significant
effects
both
average
diurnal
temperature
precipitation
probability
species
melanistic,
so
more
frequent
colder
wetter
climates.
Elapidae
seems
highly
correlated
temperatures,
likely
compared
normal
colourations
boost
thermoregulation
under
favourable
conditions.
broad‐scale
conclusions
still
must
drawn
squamates,
research,
provide
additional
TMH
key
adaptive
interpretation
phenotypic
wild
populations.
Language: Английский
Niche Differentiation and Spatial Segregation of Melanistic and Non‐Melanistic Colour Morphs in a Widespread Palearctic Reptile
Journal of Biogeography,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 29, 2025
ABSTRACT
Aim
This
study
investigates
the
spatial
distribution
and
climatic
niche
differentiation
between
melanistic
non‐melanistic
colour
morphs
of
common
adder
(
Vipera
berus
)
across
species
range.
We
aim
to
elucidate
role
environmental
factors
in
shaping
geographic
ecological
variation
polymorphism
within
this
species.
Location
The
Palearctic
region.
Methods
first
compiled
georeferenced
occurrence
records
from
citizen
science
databases
map
adder's
V.
).
Then,
point‐pattern
analyses
were
employed
assess
segregation
morphs.
Climatic
was
quantified
using
both
univariate
density
profiles
multivariate
approaches.
Niche
equivalency
similarity
tests
performed
determine
extent
overlap
divergence
morphs'
niches.
Results
results
reveal
significant
morphs,
with
individuals
predominantly
occurring
colder,
more
arid
regions.
Despite
considerable
overlap,
indicate
a
marked
differentiation,
morph
occupying
narrower
environmentally
extreme
compared
morph.
confirm
that
while
niches
are
distinct,
they
similar
than
would
be
expected
by
chance.
Main
Conclusions
findings
suggest
observed
patterns
shaped
via
local
adaptation.
differential
likely
reflects
adaptive
responses
temperature,
precipitation
habitat
structure,
further
refined
mechanisms
such
as
predation
pressures
thermoregulatory
trade‐offs.
These
provide
complementary
perspective
on
polymorphism,
supporting
specialisation
under
constraints,
highlighting
value
data
capturing
large‐scale
phenotypic
variation.
Language: Английский
Melanism in Polymorphic Terrestrial Snakes: A Meta‐Analysis and Systematic Review
Journal of Biogeography,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Sept. 22, 2024
ABSTRACT
Background
and
Aim
Colour
polymorphic
populations
constitute
excellent
model
systems
for
testing
ecological
evolutionary
hypotheses,
as
alternate
colourations
are
associated
with
differences
in
various
biological,
behavioural
life‐history
traits.
Melanism
is
the
most
common
obvious
form
of
polymorphism.
In
reptiles
general
(and
snakes
particular),
thermal
melanism
has
been
a
popular
hypothesis
used
to
explain
appearance
black
individuals.
It
suggests
that
trade‐off
exists
between
superior
thermoregulation
reduced
protection
through
loss
crypsis.
Surprisingly,
despite
growing
body
literature
available,
date,
there
only
two
qualitative
reviews
on
significance
no
quantitative
synthesis.
We
conducted
first
systematic
review
meta‐analysis
summarising
current
knowledge
terrestrial
synthesised
evidence
an
adaptive
advantage
melanistic
morph.
Location
Northern
Hemisphere.
Taxon
Polymorphic
snakes.
Results
Mean
prevalence
31%
significant
species.
Annual
precipitation
was
moderator
prevalence.
Our
results
revealed
odds
ratios
sexes
or
mean
size.
Main
Conclusions
Environmental
plasticity
can
be
considered
primary
cause
melanism,
possibly
result
seasonal
climatic
variations,
corroborated
by
formal
conducted.
from
follows
Gloger's
rule,
case
birds
mammals,
opposed
hypothesis.
Further,
our
findings
do
not
lend
support
other
predictions
hypothesis,
such
skewed
frequency
melanistics
favour
males
females,
larger
sizes
hold
implications
future
diversity
animal
populations,
climate
change
predicted
decrease
degree
colour
variation.
Language: Английский