Techniques for studying insect migration

1. TECHNIQUES FOR STUDYING
INSECT MIGRATION
ATHIRA G MENON
PG16AGR8016
SEMINAR II
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2. Flow of seminar….
Introduction
Migration
Different techniques
Case studies
Conclusion
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3. Insect migration- few definitions
• “To go from one habitat to another” -Oxford English Dictionary.
• “A continued movement in a more or less definite direction, in which both
movement and direction are under control of the animal concerned”-
Williams,1958.
• ‘Migratory behaviour is persistent and straightened-out movement effected by
the animal’s own locomotory exertions or by its active embarkation on a
vehicle’.- Kennedy 1985.
• “Transfer of populations from place to place by mass flights”- G Johnson, 1969
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Costs and benefits of these migrant insects are variable…
so it is crucial to understand how they migrate.

5. Population dynamics
Ecology
Evolution of insect
Chapman et al. 2008

6. Types of migration
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Seasonal migration
Reproductive migration
Irruptive migration
Nomadic migration
Painted lady butterflies
Monarch Butterfly
El nino weather
effects
Salt marsh mosquitoes
Locust

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Day time migration Night time migration
• Smaller insects carried upward
beyond the limits of their
boundary layers by thermal rising
from ground.
• No radiation thus no thermal
rising from ground
• Insect may not be in control of
flight
• Insects depends on their own
activity to carry them upward
• Wind aided transport • Take off in large number after
sunset

8. Why migration???
• Food Source
• Breeding
• Change in climate
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9. Importance of migration
• Bio indicators
• Exchange of gene pool
• Understand insect population dynamics
• Forecast systems
• Easy to orient general public towards nature
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10.  List of migrating species
Class Species Location Numbers Distance Reference
Insects Dragonfly Argentina 4-6 Billion 11,000 miles Chapman et al. 2008
Monarch Mexico 200 Million 3000 miles Chapman et al. 2008
Desert Locust North Africa 109 -10 11 20 km² swarm Chapman et al. 2008
H.armigera Brazil 1000 km (Pedgley 1985)
Dragonfly Monarch Butterfly Locust

11. Techniques for
studying insect
migration
directly indirectly
Tracking of the movement of
individuals
Monitoring the displacement of
populations
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Osborne et al. 2002

12. Techniques
1. Marking and recapture
2. Traps and Arial nets
3. Tracking paths
RADAR (VLR)
LIDAR
4. Isotopes
5. Behavioural observations(flight mills
& wind tunnels)
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13. a. Tags and related markers
• Mammals, reptiles, amphibians, fish and birds
• Dispersal and population ecology studies
1. Marking and recapture
• How a marker should be?
•
MONARCH WATCH
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14. b. Mutilation marking( rarely used)
• Clipping- lepidopterans
• Notching- orthopterans
• Punching
• Etching
• Butterflies, beetles, dragon flies, grasshoppers
beetles
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15. c. Paint and ink marking( widely used)
• Marking individual insects
• Marking groups of insects
Dot coding system to mark individual beetles
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16. d. Dust marking
• Tumbling/shaking
• puffing
Day-Glo
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17. e. Molecular markers
Molecular markers
Non recombinant markers
Nuclear genomic markers/Protein
markers
• DNA markers available are
RFLPs- Restriction Fragment Length Polymorphism.
RAPDs- Random Amplified Polymorphic DNAs.
SSCPs- Single Stranded Confirmation Polymorphism.
Mini and Micro satellites etc.
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Migration and genetic structure of the grain aphid ( Sitobion avenae) in Britain
related to climate and clonal fluctuation as revealed using microsatellites
Llewellyn et al., 2002
• Sitobion avenae samples were collected in the 12.2-m high suction traps of the
Rothamsted Insect Survey thereafter stored in 95% ethanol prior to microsatellite analysis
DNA was extracted from individual aphids
Genotypes of individual S. avenae were examined at
four microsatellite loci (Sm10, Sm11, Sm12 and Sm17)
(Sm11 is X-linked, while the others are autosomal)
PCR
kent
470 km
N

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Llewellyn et al., 2002
Histograms showing allele frequencies at four microsatellite loci (Sm 10, 11, 12and 17)
• allele frequencies appear
generally rather similar at
both sites, leading to the
inference that the insect is
highly migratory.

20. 2. Traps and Arial nets
• Examine changes in insect population densities
• Helps to identify dispersal patterns.
• Highly influenced by weather and lunar cycle.
• Eg:pheromone/light trap network operating in
eastern Africa to monitor the movements of the
African armyworm, Spodoptera exempta
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Suction trap
Light trap
Arial nets
Pheromone
trap

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An aerial netting study of insects migrating at high altitude over England
Chapman et al. 2004
• Day and night sampling of windborne arthropods at a height of 200 m above
Ground using a net supported by a tethered balloon.
• High-flying migrant insects have been sampled with nets suspended from
tethered aerodynamically-shaped balloons (blimps), kites or aircraft
• The net - nylon mesh, was ~ 2.2 m in length with an entrance aperture
of 0.64 m².

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Chapman et al. 2004
Catches obtained during arial
netting
study at 200m above Bedfordshire
Mean aerial density

23. 3. Tracking paths
• Eye /video/RADARs.
• Tracking by radio telemetry-Osmoderma eremita
(Scarabid beetles).
• Used for studying Dragonfly and Locust migration in
UK.
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24. RADAR
• RADAR is an acronym for Radio Detection And Ranging.
• Works in frequencies of ultra high range.
• System works on Doppler effect and echo.
• Used to track motion, speed and direction of objects.
• Radar signals pass the speed of light.
C=300,000km/s
• Range= C* time/2
• G. W. Schaefer (1968) - “The father of Radar Entomology”
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26. Traditional radar vector display
• Beam is reflected from the center to the edge once
for each pulse.
• Angle of each deflection matches angle of radar dish.
• Return signal intensifies the beam, making a spot.
• Angle of target
=vector display angle
=angle of antenna dish
• Target distance
=distance from the Centre of screen
=travel time for reflected pulse
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28. RADAR Pulses always getting “smarter”-
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• VLR( Vertical Looking RADAR)
Emits circularly symmetric vertical
looking beam in which plane of
polarization is continuously rotated.
Shape of insect(σxx:σyy ratios)
Orientation behavior
Target’s mass

29. Downwind migration of the African armyworm moth, Spodoptera
exempta, studied by mark-and-capture and by radar
04-05-2018 29Rose et al,1985
 Dye used – Neutral red
 Composition of diet = 80% water,20% molasses and 0.5% Neutral Red
 About 166,OOO African armyworm moths, Spodoptera exempta ,were
marked at an emergence site near Nairobi when they fed at night on trees
baited with dyed molasses.
 Moth flight trajectories deduced from radar
 Balanites aegyptica (L.), and Acacia drepanolobium

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Six marked moths were caught on the sticky pheromone
traps at distances of 35- 147 km from the marking site
radar echoes from large
numbers of moths streaming
westwards
Rose et al,1985
• The average distance flown by the
captured moths was 75±47 km

31. LiDAR (Light Detection And Ranging)
• Optical remote sensing technology that can
measure the distance to, or other properties of a
target by illuminating the target with light, often a
pulse from laser
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32. Laser signals are emitted
Laser signals reach the obstacle
Signals reflect from the obstacle
Signal return to the receiver
Laser pulses are generated
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WORKING PRINCIPLE

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Agricultural pest monitoring using fluorescence lidar
techniques
Mei et al. 2012
Energy= 25mJ
Pulse width =10ns
H. armigera, S. litura S. exigua
Laboratory experiment

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Field arrangement
• Remote fluorescence measurements were performed by
marking four S. litura specimens (about 20 mm in length) with
different dyes, and then mounting them with very thin non-
fluorescent copper wires to a baluster on a 50 m remote
platform.
• Dyes used = Comet Blue, Stellar Green, Lunar Yellow and
Nova Red.
Mei et al. 2012

35. Isotopes
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• An alternative to electronic devices is to use stable isotopes as natural tracers
of migration or dispersal. The principal biologically important elements (e.g.
carbon, nitrogen and hydrogen) have each at least two stable (i.e. non-
radioactive) isotopes.
• When the butterflies emerge, the isotope ratios in their wings become “fixed”,
such that the signature in any butterfly or moth faithfully reflects where it
lived as a caterpillar.

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Natal origins of migratory monarch butterflies at wintering
colonies in Mexico: New isotopic evidence
Wassenaar & Hobson,1998
• Stable hydrogen (𝛿D) and carbon (𝛿13C) isotope ratios of wintering monarchs can be used to evaluate
natal origins on the summer breeding range.
• Stable-hydrogen and carbon isotopic values of 597 wintering monarchs from 13 wintering roost sites
were compared with isotopic patterns measured in individuals at natal sites across their breeding
range over a single migration cycle.
• 50 males and females selected randomly from each colony
Ascalapia sp.
Isotopic patterns in rainfall for 𝛿D and
other climatic and physiological
factors for 𝛿13C
Natal sites

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Location of 13 overwintering colonies
Wassenaar & Hobson,2002
Considerably overlapping among
overwintering colonies

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Originated from fairly restricted part of breeding area
95% monarch from all wintering sites
Natal origins of monarch butterflies wintering in
Mexico derived from 𝛿 D and 𝛿 13C data
EASTERN NORTH
AMERICA
CENTRAL
MEXICO
Wassenaar & Hobson,1998
N

39. Wind tunnel
• A wind tunnel is a tool used in aerodynamic research to study the effects of air moving past solid
objects. A wind tunnel consists of a tubular passage with the object under test mounted in the
middle. Air is made to move past the object by a powerful fan system or other means. The test
object, often called a wind tunnel model.
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40. Flight mill
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Microcontroller board

42. Graphical representation of flight mill data
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43. Migratory behaviour of Helicoverpa armigera (Hubner) using tethered flight mill
Jyothi (2017)-unpublished04-05-2018 43

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Jyothi (2017)-unpublished
21.81
8.19
1.02
3.42
6.62
1.61

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Jyothi (2017)-unpublished

46. • Depends on the data from a combination sources we can successfully study the Population dynamics,
Evolution and Ecology of insects.
• Entomological radars have made a huge contribution to understanding windborne insect migration.
• Applications- Forecasting, Modelling, Pest management etc.
• Common to all studies of insect migration is the need for rigorous analytical approaches, capable of
identifying any bias in the data, and further work is needed in this area.
• A multidisciplinary approach, involving direct techniques (such as mark–recapture and tracking) in
combination with indirect techniques (such as trapping networks and use of genetic markers) is essential
in the future study of insect migration.
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CONCLUSION

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