Microevolution of a red squirrel population caused by climate change Vincent Arcega April 23, 2013

Phylogeny Kingdom:AnimaliaAnimalia Phylum:ChordataChordata Class:MammaliaMammalia Order:RodentiaRodentia Family:SciuridaeSciuridae Genus:TamiasciurusTamiasciurus Species:T. hudsonicus

Facts Length30 cm Weight 280 g Lifespan 6 years Habitat trees

Diet Conifer seeds, flowers, berries.

Predation Birds, lynx, coyotes.

Genetic and plastic responses of a northern mammal to climate change Authors: Denis Reale, Andrew G. McAdam, Stan Boutin and Dominique Bertaeaux

Genetic and plastic responses of a northern mammal to climate change As climate increases due to global warming animals must cope through physiological changes or microevolution.

Purpose of study Microevolution is the changes in allele frequencies that occur over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow, and genetic drift.mutationnaturalartificialgene flowgenetic drift

Purpose of study Red squirrels are studied for how they have adapted to the climate change with changes in spring weather and food abundance.

Purpose of Study Breeding was documented over four generations. Parturition date is hereditary. If parturition date changes then the results may be from microevolution. Life span of Red Squirrel?

Reproduction Red squirrels breed once or twice a year, depending on their geographic location The breeding season begins in midwinter from March to May. Followed by August to early September.

Reproduction * Females are in estrus only 1 day per breeding season! Conception usually occurs within a few hours of mating.

Climate Change Earth's average temperature has risen by 1.4°F over the past century, and is projected to rise another 2 to 11.5°F over the next hundred years (

www. epa.gov

The orange line shows the first arrival of frost in the fall, which is occurring later in the year than previously. The green line shows the timing of the last spring frost, which is occurring earlier in the year than previously.

Material and Methods The study was near Kluane Lake, Yukon, Canada. The habitat was open boreal forest 325 squirrels were ear-tagged Reproductive activity monitored yearly.

Breeding Value This represents the combined additive effects of all an individual’s genes for a given trait and changes in estimated breeding values (EBVs).

Breeding Value This approach helps differentiate between temporal phenotypic changes due to genetic and environmental sources

Environmental changes and reproduction Females born in 1989 and 1998 lifetime parturition date was calculated. Food is counted every August. Yearly spruce cones were a measure of the average food abundance.

Maternal Effects Five maternal characteristics that may affect EBV: Maternal Age Litter Size Postpartum body mass Maternal reproductive investment Spruce cone index.

Microevolutionary changes in parturition date Females born in 1989 and 1991 were assigned generation one Females after 1991 regardless of the year born were 1 generation higher than their mother.

ResultsFactor: Environment Spring temperature has increased by nearly 2˚ C No particular trend for precipitation Number of cones have increased by over 35% Note: For weather temperatures you can make a rough conversion from Celsius to Fahrenheit by doubling the figure and adding 30.

Results Factor: Reproduction The past decade has shown advance increase in parturition date. Red squirrels born in 1989: from January 1 to May 8 (128 days).

Results Factor: Reproduction Red squirrels born in 1998: from January 1 to April 20 (110 days) 128 days – 110 days = 18 days Reproduction has changed 18 days in the past decade.

Phenotypic Plasticity Food abundance had large effect on reproduction. This indicates a large amount of phenotypic plasticity and a strong effect on breeding.

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In Conclusion In the past 27 years Yukon has increased in spring temperatures and also an increase in food. The response was an 18 day advancement in breeding. The red squirrels have experienced phenotypic changes and microevoltuion.

In Conclusion From the author: “The combination of phenotypic changes within generations and microevolutionary changes among generations resulted in large phenotypic responses to rapid changes in environmental conditions experienced by this population of squirrels over the past 10 years.”

Questions, Comments, Concerns.