larval period
DESCRIPTION
The influence of larval growth history and exogenous thyroid hormone on life history allocation patterns in the axolotl ( Ambystoma mexicanum ) Pamela M. Clarkson and Christopher K. Beachy Minot State University. metamorphic size. larval period. Wilbur and Collins, 1973. - PowerPoint PPT PresentationTRANSCRIPT
The influence of larval growth history and exogenous thyroid hormone on life history allocation patterns in
the axolotl (Ambystoma mexicanum)
Pamela M. Clarkson and Christopher K. BeachyMinot State University
larval period
met
amor
p hic
s ize
Lab manipulations of growth almost never confirm this.
This pattern is uncommonly observed in nature.
Wilbur and Collins, 1973
energy intake
larval period
met
amor
p hi c
size
larval period
met
amor
p hi c
size
larvalgrowth
metamorphicdevelopment
storagesexual
maturation
energy intakelarval
growth
storagesexual
maturation
larval period
met
amor
p hi c
size
larval period
met
amor
p hi c
size
energy intakelarval
growth
storagesexual
maturation
energy intakelarval
growth
metamorphicdevelopment
storagesexual
maturation
Ambystoma mexicanum
Ambystoma mexicanum
+ 5 nM TH
TIMELINEin days
hatching
initiate foodtreatments
first metamorph
last metamorphinitiate TH
treatmentsswitch foodtreatments
firstweighing
secondweighing
thirdweighing
fourthweighing
14 March2007
21 January2008
Metamorphic(and control)
weights
metamorphic timing (TH)gonad massfat body massmetamorphic mass
Two-factor MANOVA
control
5 nM TH
5 nM TH
Big Gonads
Big fat bodies
0
10
20
30
40
50
60
70
0 20 40 60 80 100
days to metamorphosis
meta
morp
hic
mass (
g)
switched tolow food
switched tohigh food
met
amor
phic
mas
s (g
)Metamorphs (TH treated animals)
0
100
200
300
400
500
600
0 500 1000 1500 2000
gonad mass (mg)
fat
bod
y (
mg
)
switched tohigh food
fat
body
mas
s (m
g)
0
100
200
300
400
500
600
0 500 1000 1500 2000
gonad mass (mg)
fat
bod
y (
mg
)
0
100
200
300
400
500
600
0 500 1000 1500 2000
gonad mass (mg)
fat
bod
y (
mg
)
0
10
20
30
40
50
60
70
80
90
100
low switch to high switch to low high
fin
al
mass (
g)
0
10
20
30
40
50
60
70
80
90
low switch to high switch to low high
fin
al
mass (
g)
PAEDOMORPHS METAMORPHSfa
t bod
y m
ass
(mg)
fat b
ody
mas
s (m
g)
Our Results
• In the low-high group, metamorphosis was delayed similar to the Wilbur-Collins hypothesis
Final Analysis
• Suggests storage and metamorphic development interact classic Wilbur-Collins model
• Storage rather than growth may be an indicator of environmental quality or deterioration
ACKNOWLEDGMENTS
Heather Modrow (MSU)Leah Crites (MSU)Charles Crites (MSU)Sharon Denks (FBCC)Dwight Blackhawk (FBCC)Karen Pocha-Melby (MSU)