There are many facets involved in the development of biogeochemical markers that might enable the geographic origins of fruit flies to be distinguished.

1. biosecurity built on science
Exploiting Hydrogen and Oxygen as Components of a Natal Origin
Biogeochemical Marker is Challenging but Promising
(PBCRC2111)
Karen Armstrong & Peter Holder (BPRC)
David Murphy & Karine Harumi Moromizato (QUT)
Peter Crisp (SARDI)
Bill Woods (DAFWA)
Solomon Balagawi (NSW DPI)
with
Robert Van Hale & Dianne Clarke (Univ. Otago)
Plant Biosecurity Cooperative Research Centre

2. biosecurity built on science
Natal origins of fruit flies
Non-
established
Potentially
breeding
Confirmed
breeding
population
15 M
4 M
2 M
1 M
0 M
EstimatedcostsNZD
e.g. estimated cost QFF incursion, NZ (2015)
 Is this fly from a locally established
population or has it just arrived?
 Do we know where from?

3. biosecurity built on science
Stable isotope geographic markers: δ2H and δ18O
99.985% 0.0026–0.0184%
O8
8 O10
8
99.76% 0.20%
Light Heavy

4. biosecurity built on science
Challenges for biosecurity application
Technical:
‐ Can geographic areas be resolved at a relevant spatial scales?
‐ Generation of reference ‘isoscapes’
‐ Can existing technology be adapted for smaller insects?
‐ Can conclusions be drawn from only a few insects?
Biological:
‐ How faithful is the environment-to-plant-to-insect signature?
‐ Does polyphagy matter?

5. biosecurity built on science
How good is the spatial resolution within Australia?
xx xx
x
xxx
x
x
xx
xxx
x
xxxx
x
xx
x
x
x x
xxx
x
x
x
x
xxxx
x
xx
Kunanara
Broome
Carnarvon
x xx
x
x

6. b
b
a
Fishers LSD=5%
Empirical evidence of regional discrimination
National International
Grey Lynn incursion, AKL, NZ (2015)
Arophelus ferus Lubomír
Klátil

7. biosecurity built on science
Gathering data to develop relevant isoscapes
August
December
Australia Asia
δ2H: www.waterisotopes.org
http://www.ansto.gov.au/AboutANSTO/M
ediaCentre/News/ACS101040 July 2016

8. biosecurity built on science
Now understand the fractionation relationship
-5
0
5
10
15
20
25
30
-70 -50 -30 -10 10 30 50 70 90
δ18O
δ2H
Q-Fly and medfly water to wing 2H and 18O Δ
Q-fly T1 medfly T1 Q-fly T2
medfly T2 Q-fly T3 medfly T3
Water T1 Water T2 Water T3

9. How many individuals needed for confident assignment?
Are these NZ H. armigera
from NZ?
Are these AUS H. armigera
from NZ
(Naïve Bayes analysis)
(Boosted regression tree
analysis)

10. Choosing the right tissue for analysis
Adult flies on treatments for 13 diff. periods, 0 – 90 days:
 T1 starved (no water)
 T2 control (same water)
 T3 water enriched for d2H & d18O
5 samples per time period, various tissues used for H & O
analysis
Results pending….
Does adult feeding influence the natal signature via tissue turnover?

11. biosecurity built on science
Summary - H & O isotope ratio markers of origin
Challenges
• Developing relevant reference
isoscapes – local, regional,
international?
• Developing a multivariate systems
‘model’ for end user application
Promises
• Technology to analyse single insects
rapidly is possible
• Number of insects needed is low
• We understand the δ2H & δ18O
signature food-to-fly transmission
• Wild fly regional differences can be
greater than any seasonal or host
variation

12. biosecurity built on science
The End-User Advocate’s perspective
 Various uses for knowledge of natal origins:
- declarations of area freedom
- indicator of regions generating infested produce
- understand local pathway risk – landscape use, preferred sites & travel corridors
 Ultimate end users/beneficiaries:
- horticultural industries susceptible to fruit fly
- inter-state quarantine (regulators and risk managers)
- funding providers for regulatory activities, funding bodies for better targeted research
for international market access
 Climate change
- Qfly range expanding so NZ, Tasmania and South Australia under increasing pressure
to maintain area freedom = intensified interest in evidence for source of a breach.
Bernie Dominiak, NSW DPI

13. biosecurity built on science
Thank you