Stickleback Research

Question 1

Habitat

Answer 1

Northern hemisphere, marine, coastal, streams, lakes

Question 2

Sexual Reproduction

Answer 2

Enter coastal streams, male build nest, court female, tend eggs, protect fry, then dies
Aerate eggs, fry return to ocean, 2 years at sea, return to spawn

Question 3

FW forms different from marine

Answer 3

smaller body
Fewer spines and body armour
This is presumed to be because less predation

Question 4

Stickleback sampling

Answer 4

In the woods

1979-1990 sampled 700 lakes

140 lakes with sticklebacks

mostly intact lakes, post-glacial, no non-native species

Found that buttressing plates keep spine stiff

Question 5

Pursuit-Escape Adaptations

Answer 5

Less armour for burst acceleration, and better turning radius
This is often associated with larger body sizes

Question 6

Post-Capture Adaptation

Answer 6

Puncturing Predators: They armour bodies fully
Compression Predators: Reduced armour, with most near front
Grappling Predators: no armour or spines

Question 7

Lake Colour Effect

Answer 7

Red lakes, low visibility
This favours escape adaptation
Clear Lakes favour, post-capture adaptations

Question 8

Lake Size Effect

Answer 8

Small lake less armour/spines compared to large lakes

Question 9

Experiment

Answer 9

Transfer 100 adults from Mayer Lake (giant stickleback)
Mayer lake: dystrophic, zooplankton, salmonid/bird predation
Roadside Pond: eutrophic, ostracods/larvae, naiads/kingfisher predation
To a small pond with no fish
Predict a reduction in size, reduction in gill rakers, change in food source, and predators to change
Measured 1993-2009 (8 generations)
Found in 8 generations many phenotypic characters had changed

Question 10

DNA sequencing of Stickleback

Answer 10

Sent 23 stickleback for DNA testing from transplant compared to natural
Many localized signatures across many chromosomes
Direct selective effects across genome
Transplant change same as allopatric population
Up to 72% adaptive genome-wide differentiation in 13 generations
Essentially opposite to previous expectations that genomic constraints would hold back the potential for adaptation and evolution
Genomic change faster than phenotypic change

Question 11

Major Morphological Findings

Answer 11

15% reduction in adult length
46% reduction in lateral plate 2 frequency
17% reduction in relative height of lateral plate 3
12% reduction in relative length of pelvic spine
21% reduction in relative length of dorsal spine
5% reduction in gill raker number
37% reduction in relative length of gill rakers
5% increase in relative distance between gill rakers
5% increase in relative length of jaw
8% increase in relative diameter of eye
major loss of melanism