Multiple mating of female Dioryctria in British Columbia conifer - - PowerPoint PPT Presentation

Multiple mating of female Dioryctria in British Columbia conifer seed orchards

Caroline Whitehouse, Ward Strong and Maya Evenden

Jason Dombrowski Jason Dombrowski

Multiple mating theory

• Levels of polyandry can vary widely among and

within species

• Fitness and evolutionary implications
• Benefits to females are unclear
• Direct and indirect benefits
• Increasing female fecundity
• Increased genetic variability

en.wikipedia.org/wiki/Gryllus_bimaculatus

Influence of multiple mating on pest management

Mating disruption using sex pheromones:

• Prevention and temporal delay of mating
• Occurrence and prevention of multiple mating

www.hortnet.co.nz/key/keys/info/control/cmcontr/cm- disr.htm www.btinternet.com/~micka.wffps/codling_moth.jpg

Dioryctria Zeller (Lepidoptera: Pyralidae)

• 40 North American species, 12 in British Columbia
• Destructive pests on Pinaceae
• Cone, foliage, cambium and wounds
• Economically important

Ward Strong Ward Strong

Objectives

• Are female Dioryctria polyandrous?
• Does the level of polyandry/monandry differ

among species?

• Within species does the occurrence of polyandry

change throughout the season?

• Does this seasonal pattern differ among species?

Methods

• Light trapping conducted at two commercial and
• ne research Douglas-fir seed orchards
• June 19 - Sept 19, 2008
• May 4 – September 26, 2009
• Traps run 5 days/week and catch collected twice

Methods

• Excise female genitalia
• Identify to species group

Bursa copulatrix Ductus bursae

• Count spermatophore

number

Species groups caught

abietella gr. auranticella gr. zimmermani gr. ponderosae gr. schuetzeella gr.

Photo credits: Amanda Roe

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 abietella auranticella ponderosae schuetzeella zimmermani

Proportion of females trapped Species group

Virgin Once mated Multiply mated

Mating status of females

19 34 354 5

114

Poly- and monandrous females

0.00 0.50 1.00 1.50 2.00 2.50 3.00 abietella auranticella ponderosae schuetzeella zimmermani

Average number of spermatophores Dioryctria species groups

a b c c c

Frequency of rematings

0.0 0.2 0.4 0.6 0.8 1.0 1 2 3 4 5 6 7

Proportion of total females Spermatophore number

abietella gr. auranticella gr. ponderosae gr. schuetzeella gr. zimmermani gr.

Seasonal variation in mating frequency

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Weekly average spermatophore number Week number

abietella auranticella ponderosae schuetzeella zimmermani

2009 2008

Seasonal variation in mating frequency

F P

species F= 5.04 0.01 weeknumber F= 0.38 0.97 species*weeknumber F= 1.12 0.39 abietella F= 1.02 0.45 auranticella F= 6.53 0.03 ponderosae F= 0.68 0.70 schuetzeella F= 1.99 0.06 zimmermani N/A N/A

Conclusions

• abietella gr. and auranticella gr. are polyandrous
• seasonal patterns differ
• schuetzeella is monandrous
• Mating frequency as a function of population density
• Pest management concerns
• Dioryctria useful as a model system for studying multiple

mating

Future studies

• Establish if polyandry = higher fecundity
• Impact of male investment on female fitness and

particularly female receptivity

• Determine if seasonal increases in mating frequency

could be a function of population density

Acknowledgements

Torie Lewis, Faye, Natalka Melnyky Kalamalka Research Station staff

• Dr. Amanda Roe

Members of the Evenden lab

• Dr. Felix Sperling
• Dr. Nadir Erbilgin

Financial support from the Forest Investment Account funds administered by Forest Genetics Council of British Columbia Travel assistance provided by the Faculty of Graduate Studies and Research, University of Alberta

http://www.softwood.org/Douglas%20Fir%20Web/eDougFir/EN/DougFir.htm