Flowers, aphids and ants: a love story

Team EchinaceaSummer 2009

Once upon a time …

• Fragmentation broke up virtually continuous prairie habitat filled with Echinacea angustifolia.

Echinacea distribution

Once upon a time …

• Fragmentation broke up virtually continuous prairie habitat filled with Echinacea angustifolia.

• Remnant populations, in small patches of habitat untouched by cultivation, remain.

• Fragmentation has ecological and evolutionary effects on populations.– Alteration of mating patterns

Mating patterns

• Which individual a plant mates with can depend on …– Proximity to other plants– Movement of pollinators– Genetic compatibility– Human intervention

• Fragmentation can increase matings between relatives.

• Restorations may increase matings between remnant populations.

Study of mating patterns• Collected seeds from open pollinated heads in

several remnant populations in Douglas County.

• Plants them in the common garden (96/97 garden).

• Hand-crossed individuals in 1999 and 2000.– Between remnant crosses– Random, within remnant crosses– Sib-crosses (individuals from the same head in the

remnant)• Planted them in the common garden (inb1).

Fitness of inb1 plants

Herbivorydamage

none

Betweenfragment

Within fragment

Sib-mated

high

Cross type

Community genetics

• Study of how the genetic composition of one species can affect composition and structure of its community.

• Example- genetic diversity of Solidago altissima plots affects the diversity of herbivores observed within the plots (Crutsinger et al. 2006).

• Could mating patterns of Echinacea have impacts on the community?

Aphis echinaceae

Aphid abundance

Ant abundance

Conceptual diagram

Plant size, morphology,

phenology, etc.

Plant stoichiometry

Plant cross typePlant cross type

Ant abundanceAnt abundance

Aphid abundanceAphid abundanceAphid stoichiometry

Ant stoichiometry

Plant biochemistry,

etc.

#5a

#4s

#5s #3a#3s

#2a#2s

#1

#4a

Future directions

• What is maximum abundance of aphids?• When does aphid abundance peak?• Can we estimate aphid population growth

rate on individual plants?• Are common garden and remnant aphid

population dynamics the same?• Why do ants tend aphids?• Others?

Ecological stoichiometry

• The study of the balance of chemical elements in ecological interactions.