Global Climate Change Program • WWF-UK & WWF-US

Dragonfly MigrationContinental-scale Movement with a Climate-

driven Pulse

John H. Matthews ° 2 August 2008

Do Dragonflies Migrate South in Fall?

with Jay Banner, Tom Juenger, Larry Mack, & Len Wassenaar

What Is Migration?Johnson, Kennedy, & Dingle: 1960 to 1996

Consensus: “Persistent, undistracted motion”

Need not be two-way movement or to/from specific localities

Often associated with special behaviors, physiological states (Dingle)

Large-scale movement rarely described in small-bodied organisms, especially insects

Movement over large scales presents strong conservation challenges

>5 x 106 individuals passing single localities in a day

Telemetry & gross (not net) movement: up to 100 km in a day (Wikelski et al. 2006)

Allegations of Migration

One of ~15 odonate species believed to migrate long distances

More Than a century of anecdotal reports

Oil platforms: individuals >100km from shore crossing Gulf of Mexico

Larvae are completely aquatic, specializing in small standing wetlands

Hydrogen isotopeprocessing

Strontium isotopeprocessing

Microsatellite DNAEstimates north-south movement

Are Adults from Coastal Areas?

Reproductive Strategy,Biogeography

Studying Movement by Individuals and

Across Generations

Individual-based Methods : : Population-based Methods

Isotopic Ratios & MovementPrecipitation Hydrogen isotope ratios (δD) Have a Strong Latitudinal Component

Marine and near-coastal water strontium ratios (87Sr/86Sr) are uniform and distinct

Runoff, underlying geology 87Sr/86Sr ratios

Precipitation δD values

— Negligible Fractionation —

— fractionated —new δD value, locked

in wing tissue

Ambient 87Sr/86Sr, locked in wing tissue

August–October 2005:16,000-km Sampling Route

19° latitude

47° latitude

How Many Degrees of Latitude Are They Flying? northwa

d

Southward

Net

latit

ude

(°)

15

20

25

30

35

40

45

50

55

60

65

0 20 40 60 80 100 120 140 160 18015

20

25

30

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0 20 40 60 80 100 120 140 160 180Individuals, sorted by collection latitude & est. origin latitude late August mid October

Collection latitude

95% Prediction Intervals for Migration Origination Latitude

Where Did They Come From?

Most are from this range

Intra-generational Movement

northwardd

movement

southward movement

Net north-south movement (km)

Freq

uenc

y

Sμ = 909 km

Globalμ = 683 km

Nμ = 558 km

no

mov

emen

t

How Are Swarms Organized?

0.70800

0.70850

0.70900

0.70950

0.71000

0.71050

-100 -80 -60 -40 -20 0 20

Calculated natal precip dD value

522937545118444649169264023322NJ marsh

above marine ratio

below marine ratio

~ carbonate ratios in Ontario & Quebec

Profiling one Flight Group in southern New Jersey

+Δ Distance flown before capture

What is microsatellite DNA?

. . . TTCAAAATCATCATCATCATCATCATCATCATCATACCAGCC . . .

Forward flanking region Reverse flanking region

1 repan arbitrary number of repeats

primer designed to fit this locus

PCR amplifies this region; with two chromosomes with this locus (one from each parent), an individual might inherit two different versions of this locus

5’-—>3’

Inter-generational Movement180 adults

12 microsatellite loci developed, 9 used

Global Fst: 0.04

Mantel: no relationship

Bayesian clustering methods (Pritchard et al. 2000; Structure 2.2)

Optimal clustering is low (1 to 2 “populations”) Adults Form a Single Population Across 27°

Latitude in Eastern North America

Testing genetic hypotheses:Microsatellite resultsclustering Type (130

genotypes)

Number of clusters Overall Fst P Value

Adult collect site 10 0.032 <0.001

Males v. females 2 0.007 0.003

Atlantic coast, Gulf coast, Lake Huron, Ontario 3 0.009 <0.001

Collected above/below 30° N Lat 2 0.003 0.02

Individual based Bayesian clustering optimal: 2 0.052 NA

Migration Conclusions

First conclusive proof of large-scale odonate migration

Individuals traveling up to 2800 km net north-south distance

One of the largest-scale insect migrations ever described

Spring northern movement must be explored in more detail

New suite of inexpensive & synergistic techniques to describe large-scale movement by insects

Should have a wide variety of conservation applications

Are Anax junius Populations Spatially Structured?

With Tom Juenger & Sandra Boles

How related are migrants & residents?Is there population structure within/between categories?

Scales of Genetic Organization Across the Landscape

In a set of eggs

Within a single pond

Throughout a region

• Females, males mate with multiple individuals

• Other odonate females store sperm• May only be half-sibs

• Males guard shorelines, females visit ponds on a more-transient basis

• Hundreds visit a single pond/day• Kinship coefficients for 19 collection

sites: ~0.05 (Ritland `96)

• Regional patterns are weak descriptors of structure (R2<0.10)

• Migration over 100s of km• Mating/egglaying en route

Spatio-temporal Patterns~450 individuals, spanning adult and larval stages

Mantel shows no spatial pattern

Larval heterozygosity declines slightly with latitude

Structure supports a low number of populations across the full range

Consensus number is one to two populations

At two populations, less than 10% of individuals are mixed between populations

The combination of category, life stage, latitude, and longitudeexplains about 22% of the population membership data

Life-stage may be conflated with temporal segregation of mating, dispersal patterns

Biogeography conclusions

Two complex suites of behavior are maintained over large spatial scales

Novel form of migration, more typical of marine than terrestrial species

adults do not leave reproductive state during the movement process

reproduction coupled with migration

Why Don’t All Anax junius

Migrate South?determinants of life-history

trajectoryWith Camille Parmesan,

Morgan Kelly, & Tom Juenger

Genetically, residents & migrants form a single group with two different phenologies and adult behaviors.

•How does an individual know to follow one or another path?•Why are there two paths? Why not one? three? or seven?

Could life-history path be a form of phenotypic plasticity?

Phenotypic plasticity: an external cue signals to an organism to follow a particular developmental path. Two obvious cues:

Larval growth rate can be regulated by temperature (Trottier 1970); common in insects

Photoperiod (daylength) had “some”influence on developmental rate on a congeneric (Corbet 1956); reliable over large scales

| hold constant

| vary by treatment

Experimental design

Eggs from a single female (unknown # males)

Constant photoperiod

Increasing photoperiod

springtreatment

Decreasing photoperiodFall

treatment

Migrantsfast

Residentsslow

Individuals raised in cups in a growth chamber

Experimental Results

0.300

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1.000

10/7/06 10/12/06 10/17/06 10/22/06 10/27/06 11/1/06 11/6/06 11/11/06

condecinc

Duration: 60 days N: 34 individuals

Constant DecreasingIncreasing

Photoperiod Treatment

Lf/Lf-25

1.5 —

3.0 —

3.5 —

Comparison of the last 26 days of growth-rate by treatment

2.5 —

2.0 —

bars show 95% CI

Constant DecreasingIncreasing

Photoperiod Treatment

Lf/Lf-20

1.5 —

2.0 —

2.5 —

Comparison of the last 21 days of growth-rate by treatment

bars show 95% CI

a

b

a

p < 0.05

Constant DecreasingIncreasing

Photoperiod Treatment

Lf/Lf-10

1.2 —

1.4 —

1.6 —

1.8 —

Comparison of the last 11 days of growth-rate by treatment

bars show 95% CI

a

b

a

p < 0.05

Life-history path conclusions

Increasing treatment was significantly different than constant & decreasing treatments

Treatments differentiated late in the experiment

Weak family effects; clear direction for future work

Rain, Rain, Go Away: Climate Change Impacts in Southern

Ontario with Camille Parmesan

Emergence phenology and precipitation normals are linked over large scales

Evapotranspiration rates are inversely related to emergence rates

Austin, Texas, 20-year climate normal data

Aus

tin, T

exas

, em

erge

nce

coun

ts

Aus

tin, T

exas

, EV

T

Caledon, Ontario: 1967–68

J. Can Ento, Trottier, 1971

Generalized Caledon emergence, 1967–68

Residents Migrants

µ=July 4 µ=Sept 13

Hiatus: 40 days

Indi

vidu

als

Calendar day

Source: Trottier 1971

Generalized Caledon emergence, 2003–06

µ~July 22 µ~August 31

Indi

vidu

als

Calendar day

Emerginglater

Emergingearlier

No hiatus

What explains opposing shifts in emergence phenology?

Air temperature?

Water temperature?

What drives water temperature in small standing wetlands?

What is the relationship between water temperature, the timing/amount of precipitation, and water volume?

Shallow-water temperatures are probably key since larvae are concentrated there

Testing drivers of shallow-zone water temperatures

From depth to volume:Some 120 sub-meter precision GIS sounding

waypoints, to generate a TIN to model volume through time

From July 2003 to August 2006:Water temps: 10 cm, 1 m depthsAir tempsWater depthsEmergence phenology

Deep-water temperatures drive shallow temperatures

Best-fit model also includes air temperatures and water volume (R2 = 0.9881)

R2 = 0.9774, p<2 x 10-6

Water temperature differences between 67 and 68, 04–06 also

explain small inter-annual phenological differences

Between May and October, water volume declines

As thermal mass decreases, differences between air and water temp also decrease

y = -0.0132x + 511.43

R2 = 0.1134

0.0

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4/28/05 5/12/05 5/26/05 6/9/05 6/23/05 7/7/05 7/21/05 8/4/05 8/18/05 9/1/05 9/15/05 9/29/05

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sVal(

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allo

w t

em

p -

Air

tem

p)

0

200

400

600

800

1000

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Vo

lum

e (

m^

3)

Abs(shallow-air) volume

Dragonfly emergence 2003–06

Indi

vidu

als

Calendar day

Much more rain in May since 1968

Much less rain in August since 1968

Emerginglater

Emergingearlier

More thermal mass, cooler water Less thermal mass,

warmer water, shorter hydroperiod

No hiatus

AcknowledgmentsAcknowledgments

• Field Assistance– Tony Alexander– Charles Britt– Nathan Burnett– John Crutchfield– Laurie Goodrich– Jeremy Harrison– Mike & Darleen McCormick– Marie Riddell– Alex Riddell, M.D.– Kieran Samuk

• Lab Assistance– Sandra Boles– Sung Chun– Abbie Green– Jamie Lee– Tierney Wayne– The Jansen lab

• Additional Support– Damon Broglie, GIS analyst– Anthony Cognato, Michigan State

Univ– Philip Corbet, Edinborough– Mike May, Rutgers University– Rob Plowes– The Parmesan lab

Th J l b

• Field Assistance– Tony Alexander– Charles Britt– Nathan Burnett– John Crutchfield– Laurie Goodrich– Jeremy Harrison– Mike & Darleen McCormick– Marie Riddell– Alex Riddell, M.D.– Kieran Samuk

• Lab Assistance– Sandra Boles– Sung Chun– Abbie Green– Jamie Lee– Tierney Wayne– The Jansen lab

• Additional Support– Damon Broglie, GIS analyst– Anthony Cognato, Michigan State

Univ– Philip Corbet, Edinborough– Mike May, Rutgers University– Rob Plowes– The Parmesan lab

The Juenger lab

• My Committee• Camille Parmesan, advisor

– John Abbott– Jay Banner, Geosciences – Thomas Juenger– Michael Singer

• Lab Mentors– Sandra Boles, Duke University– Larry Mack, Geosciences

• My Family & Friends• Kerry Watkins

Funding & SupportJohn AbbottJay BannerThomas JuengerCamille Parmesan

UT Brackenridge Field LaboratoryUT Environmental Science InstituteHawk MountainNational Science FoundationUT Section of Integrative BiologyUT Vice President of Research

Lorraine Stengl, M.D.The McLachlen family, Dripping SpringsThe Blattstein family, Tucson, AZ

More Acknowledgments