Oregon State University | Crop and Soil Sci. Dept. | College of Ocean and Atmospheric Sciences | Alex Hughan 2 1/19/2012 Its Cold! 2/06/2014

Oregon State University | Crop and Soil Sci. Dept. | College of Ocean and Atmospheric Sciences | Alex Hughan 1

1/19/2012

Its Cold!2/06/2014

Discovering the overwintering habits of D. suzukii

Alex Hughan*, Amy J Dreves, and Amanda Ohrn


Eric Simmons

Eric Simmons

Eric Simm

ons

Overwintering Abilities of SWD

• Little is known in literature• 400 flies (Kanzawa 1939)

• <1% survival over 3 years• Trap catch shows same trend• Winter refuges & heat island effect (Coop and Dreves Unpublished)

• Late fall morph • Increased cold acclimation ability

(Shearer and Brown Unpublished Data)


Eric Simm

ons

Overwintering Abilities of Drosophila Family

• D. melanogaster species group • Stored triacylglycerols (Ohtsu et al. 1993)

• Cold hardening and acclimation (Rajamohan et al. 2009)

• D. pseudoobscura • Reproductive diapause (Collett et al. 2001)

• Fertile sperm storage (Collett et al. 2001)


Motivation of SWD

• Food• Protection• Acquire Mates


Behavior of SWD

• Fall • Decomposing and late harvest fruits

• splitting grapes, decomposing apples, figs, walnut, persimmons

• Winter • Shift in abundance from crops to bordering trees

• Blueberries to surrounding trees• Spray fields show greater SWD abundance than no spray

• Spring• Feeding prior to oviposition


Past Hypotheses and Observations

• “It is said” between leaves and pebbles (Kyoiku 2003)

• D. pseudoobscura • Fermenting leaves

(Collett et al. 2001)



How can we utilize this knowledge?

• Management practices• Attract and kill• Mass trapping

• Windows of opportunity


So where are they?


Soil or duff layers?


Soil?



Soil?


Fallen Fruit?


Fallen Fruit?


Fallen Fruit?


Fallen Fruit?


Hanging Fruit?


Hanging Fruit?


Hanging Fruit?



Lichens or barks of bordering trees?






Lichens or barks of bordering trees?






Or maybe the leaf litter?





Results


Location (Sample Type) SWD Presence

Soil/Duff No

Fallen Fruit Yes (8)

Hanging Fruit Yes (6)

Cardboard Condo No

Trees/Lichens Bug Vacuum Yes (5)

Leaf Litter No

Underneath board in hoophouse Yes (3)

Under black plastic lining strawberries Yes (2)

Eric Simmons

39

Predator survey of leaf litter/soil/debris collected under late-season blueberry plants 2012

How can we interpret these finding?

• Preference for sites providing• Shelter (Architecture)• Fuel

• Future research a need for conclusive results!


A Needle in a Haystack

• Assumptions: • OW SWD Population = 5000 individuals/acre• Farm Size (BBM) = 6 square acre’s w/ 33m ceiling

• Each fly has a ~27m^3 volume space at BBM!!


What questions exist?

• What triggers SWD to enter diapause?

• Winter survival more passive or active? (<1%)

• What have SWD’s cousin’s done?


Eric Simmons

Thank You• Amy J Dreves, Amanda Ohrn for your

mentorship thus far.• A special thank you to Rich Little (retired

entomologist) and Amy J Dreves for the planning and creation of an effective bug vacuum

• BBM and DF for hosting my research on their land.

• USDA-NIFA-SCRI Grant


44Oregon State University | Crop and Soil Sci. Dept. | College of Ocean and Atmospheric Sciences | Alex Hughan

Questions?

Documents

Oregon State University | Crop and Soil Sci. Dept. | College of Ocean and Atmospheric Sciences | Alex Hughan 2 1/19/2012 Its Cold! 2/06/2014