TY - JOUR

T1 - Temperature-dependent competitive outcomes between the fruit flies Drosophila santomea and Drosophila yakuba

AU - Comeault, Aaron

AU - Matute, Daniel R.

PY - 2021/3

Y1 - 2021/3

N2 - Changes in temperature associated with climate change can alter species’ distributions, drive adaptive evolution, and in some cases cause extinction. Research has tended to focus on the directeffects of temperature, but changes in temperature can also have indirect effects on populations and species. Here, we test whether temperature can indirectly affect the fitness of Drosophila santomea and Drosophila yakuba by altering the nature of interspecific competition. We show that when raised in isolation, both D. santomea and D. yakuba display similar variation in relative fitness across temperatures of 18, 22, and 25C. However, D. santomea has higher fitness than D. yakuba when experiencing interspecific competition at 18C, while the inverse is true at 25C. Patterns of fitness across thermal and competitive environments therefore indicate that the outcome of interspecific competition varies with temperature. We then use a coexistence experiment to show that D. santomea is rapidly (within eight generations) extirpated when maintained with D. yakuba at 25C. By contrast, D. santomea remains as (or more) abundant than D. yakuba over the course of ∼10 generations when maintained at 18C. Our results provide an example of how the thermalenvironment can affect interspecific competition and suggest that some species may become more prone to extinction under scenarios of climate change through indirect effects of the thermal environment on competitive advantages between species.

AB - Changes in temperature associated with climate change can alter species’ distributions, drive adaptive evolution, and in some cases cause extinction. Research has tended to focus on the directeffects of temperature, but changes in temperature can also have indirect effects on populations and species. Here, we test whether temperature can indirectly affect the fitness of Drosophila santomea and Drosophila yakuba by altering the nature of interspecific competition. We show that when raised in isolation, both D. santomea and D. yakuba display similar variation in relative fitness across temperatures of 18, 22, and 25C. However, D. santomea has higher fitness than D. yakuba when experiencing interspecific competition at 18C, while the inverse is true at 25C. Patterns of fitness across thermal and competitive environments therefore indicate that the outcome of interspecific competition varies with temperature. We then use a coexistence experiment to show that D. santomea is rapidly (within eight generations) extirpated when maintained with D. yakuba at 25C. By contrast, D. santomea remains as (or more) abundant than D. yakuba over the course of ∼10 generations when maintained at 18C. Our results provide an example of how the thermalenvironment can affect interspecific competition and suggest that some species may become more prone to extinction under scenarios of climate change through indirect effects of the thermal environment on competitive advantages between species.

KW - climate change

KW - competition

KW - context dependent

KW - species' ranges

KW - temperature

U2 - 10.1086/712781

DO - 10.1086/712781

M3 - Article

VL - 197

SP - 312

EP - 323

JO - American Naturalist

JF - American Naturalist

SN - 0003-0147

IS - 3

ER -