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SICB 2011 Annual Meeting Abstracts
3 1 .1 VANDENBROOKS, John M.*; MUNOZ, Elyse E.; WEED,
Michael D.; HARRISON, Jon F.; Arizona State University;
jvandenb@ asu.edu
T h e R o le o f A tm o s p h e r ic O x yg en in th e E v o lu tio n o f
I n s e c t B o d y S iz e
While not all models agree, m ost estim ate th a t over the last 500
million y ea rs atm osp he ric oxygen has varied from 12% to 31%.
T he g ia n t in s e c t s of th e la te P a le o z o ic o c c u r r e d w h en
a t m o s p h e r i c P 0 2 ( a P 0 2 ) w as h ypero x ic , h in ti n g a t a r o le of
o x y g e n in t h e e v o l u t i o n of i n s e c t b o d y siz e. H o w e v e r , t h e
paucity of the insect fossil re c o rd and the complex interactions
b e tw e e n oxygen levels, organism s and com m unities have m ade
i t d i f f i c u l t to d e f i n i t i v e l y a c c e p t o r r e j e c t a h i s t o r i c a l
oxygen-size link. W e 'v e c a r r ie d o u t a u n iq u e c o m b in a tio n of
m ode rn rea rin g and fossil studies to te st this link. The results of
our r e a rin g studies su p p o rt a link b e tw e e n oxygen and size: 1)
m o st in se cts develop sm a lle r body sizes in hypoxia, an d some
d e v e l o p a n d e v o l v e l a r g e r s i z e s in h y p e r o x i a ; 2) i n s e c t s
d ev e lo p m e n ta lly an d evolution arily r e d u c e th e ir p ro p o rtio n a l
in v e stm e n t in th e tr a c h e a l system w h e n living in h ig h e r a P 0 2 ;
an d 3) la r g e r in se cts invest m o re of th e ir body in th e tr a c h e a l
system, potentially leading to g r e a t e r effects of a P 0 2 on large
insects. T h ese provide m e c h a n ism s by w hich tr a c h e a l oxygen
delivery m ay be involved in th e small size of m o de rn insects and
hyperoxia-enabled Paleozoic gigantism . The results of our fossil
stu d ie s also s u p p o r t th e oxygen-size link: 1) th e m ax im al and
a v e r a g e siz e of P r o to d o n a ta a n d P a le o d ic ty o p te r a f o s s ils
c o r r e l a t e p o s it iv e l y w ith m o d e l e d a t m o s p h e r i c o x y g en , 2)
B la tto d ea fossils sh ow ed little v a ria tio n in m axim um size, b u t
a v e r a g e size w as c o r r e la te d w ith a tm o s p h e ric oxygen, an d 3)
th e g ia n t arth ro p o d s, suc h as A rth ro p leu ra , a re outliers to an
overa ll p a t t e r n of o x y g e n - m e d ia te d body size c h a n g e . T h e s e
r e su lts s tr e n g t h e n th e a r g u m e n t th a t a tm o sp h e ric oxygen has
played a role in th e evolution of in se ct body size. S u pporte d by
NSF EAR 0746352.
7 .4 VARNER, Jo hanna M*; DEARING, M. Denise; University of
Utah; johanna.varner@ utah.edu
E s tim a tin g D u ra tio n o f In fe c tio n U sin g A n tib o d y A v id ity
A s sa y s: A P o te n tia l L im ita tio n
The n u m b e r of r e c e n t infections in a h o s t- p a th o g e n sy stem is
often reflective of th e r a te of transmission, or force of infection.
T ra d itio n a lly , la b o r i o u s m a r k - r e c a p t u r e s t u d i e s h a v e b e e n
n ec es sary to estim ate duration of infection in wildlife. Recently,
a v i d ity a s s a y s h a v e b e e n u s e d to i n f e r a g e of i n f e c t i o n a t
individual and population levels; however, th e se assays m ay be
confounded by antibody concentration. We exam ined th e effect
of t i t e r on an enzym e-linked im m u n o s o rb e n t avidity a s s a y for
Sin N om bre virus (SNV), a H antavirus prim arily ca rrie d by the
d e e r m o u s e (P e ro m y sc u s m a n ic u la tu s). A vidity in d ic e s w e r e
po sitiv ely c o r r e l a t e d w ith anti-SN V s e r u m a n t ib o d y tit e r s in
in f e c te d an im als; e x p e r im e n ta l dilu tio n of t i t e r in th e avidity
assay significantly d e c re a s e d avidity scores. F u rth e rm o re , 20%
of s a m p l e s , m o s t l y o l d e r i n f e c t i o n s w i t h low t i t e r s , w e r e
m iscla ssifie d as r e c e n t infections. T h e se r e s u lts s u g g e s t t h a t
th e avidity a s s a y classifies sa m p le s w ith low tit e r s (including
s o m e o l d e r i n f e c tio n s a n d u n i n f e c t e d j u v e n i l e s w ith d ilu te
m a te r n a l antibodies) as r e c e n t infections r e g a r d le s s of a c tu a l
infection history. As a resu lt, th e a s s a y te n d s to o v e r e stim a te
the n u m b e r of re c e n t infections in a population, which m ay lead
to falsely high estim ates of public health risk.
S IO .7 VÉZINA, F.; UniversitÄ© du QuÄ©bec Ä Rimouski;
francois vezina@ uqar.ca
C o ld a c c lim a tio n , m ig r a tio n , a n d p h e n o ty p ic
c o m p r o m is e s in a lo n g d is ta n c e m ig r a to r y s h o r e b ir d
Although t h e re is considerable know ledge on w intering ecology
of m i g r a t o r y s h o r e b i r d s , l i t t l e is k n o w n o n p h e n o t y p i c
a d j u s t m e n t s to co ld a n d h o w t h is m a y i n t e r a c t w ith o t h e r
c o n s t r a i n t s in s p e c i e s s p e n d i n g t h e i r w i n t e r s a t n o r t h e r n
l a t i t u d e s . In t h i s t a l k , I w ill r e v i e w o u r r e c e n t w o r k on
physiological a d ju s tm e n ts in re la tio n to w in te r an d m ig r a to ry
constraints in a species well known for its phenotypic flexibility:
t h e r e d k n o t (C a lid ris c a n u tu s isla n d ic a ). Isla n d ic a a r e t h e
n o r t h e r n m o s t w in te ri n g s u b s p e c ie s of kn o ts, s p e n d in g t h e i r
w in te r s on cold a n d w in d y m u d f la ts of W e s t e r n E u r o p e an d
b r e e d in g in th e C a n a d ia n an d G re e n la n d ic H igh Arctic. I will
show how th e s e b ird s im p ro v e th e ir w in te r th e rm o g e n ic
capacity and cold e n d u r a n c e by simple body m ass a djustm e nts
an d how this m ay be co m prom ised w h en conflicting w intering
c o n s t r a i n s a r e c o - o c c u r r i n g . I w ill a l s o d i s c u s s e n e r g y
m a n a g e m e n t s t r a t e g i e s in t h e s e m o ll u s c iv o re b i r d s d u r in g
e x t e n d e d p e r io d s of w i n t e r f a s tin g su c h as th o s e a s s o c ia te d
with high tide and storm y w inter w eather. Finally I will p re se n t
ou r r e c e n t w ork on g u t r e c o n s tr u c tio n following m ig r a tio n to
th e Arctic b ree d in g ground, asking w h e th e r this m ay con strain
digestive ca pac ity an d explain an o b se rv e d s te a d y in c re a s e in
basal metabolic ra te over time.
January 3-7, 2011, Salt Lake City, UT
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8 0 .1 VAN WASSENBERGH, S*; AERTS, P; Univ. Antwerpen;
sam .vanw assenbergh@ ua.ac.be
A c o m p u ta tio n a l m o d e llin g p e r s p e c tiv e on b u c c a l
ex p a n sio n d y n a m ic s a n d w a te r f lo w p a tte r n s in s u c tio n
f e e d in g fish
By p e r f o rm in g a s u d d e n ex p a n sio n of t h e m o u th cavity while
a p p r o a c h in g a prey, su c tio n fe e d e r s g e n e r a t e a flow of w a te r
t h a t d r a w s t h e p r e y in to t h e m o u th . T his p r o c e s s in v o lv e s
ex trem ely u n ste a d y flow, externally as well as internally of the
expanding m o u th cavity. Especially for flow p a t te r n s inside the
m o u th cav ity a n d r e l a t e d d y n a m ic s (e.g. t h e f o rc e s, m u s c le
p o w e r r e q u ir e m e n ts an d e n e r g e tic s for e x p a n d in g th e
buccopharyngeal cavity) our c u rre n t knowledge is largely based
o n m o d e l l i n g s t u d i e s . An o v e r v i e w is g iv e n of o u r r e c e n t
insights b a s e d on m odels of fish usin g th e com pu tatio n al fluid
d y n a m ic s (CFD) m e th o d . CFD sh o w s a g r a d u a lly d e v e lo p in g
bo u n d ary layer, w hich ca u se s th e h ig h e st velocity str e a m to be
c e n t r a l in th e e x p a n d in g cavity, w ith p e a k v elo cities slightly
p o s t e r i o r of t h e m o u t h a p e r t u r e . C o n s e q u e n t l y , a l t h o u g h
r e l a t e d to size, t h e e ff e c ts of v isc o u s f o rc e s in t h e flow c a n
g e n e r a l l y n o t b e n e g l e c t e d . T h e d i s p l a c e m e n t of
freely-suspended, non-reacting p rey items by suction is entirely
i n d e p e n d e n t of th e s h a p e of th e p re y . F in a lly , th e
(hydro)dynamical consequences of opening of the opercular and
bran c h io ste g al valves are explored, since this distinguishes the
u n i d i r e c t i o n a l n a t u r e o f s u c t i o n f e e d i n g in f i s h f r o m
b i d i r e c t i o n a l s u c tio n f e e d in g as o b s e r v e d in a m p h ib ia n s or
turtles.