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Advisor(s)
Abstract(s)
In the Mediterranean basin, the globally increasing temperatures are expected to be accompanied
by longer heat waves. Commonly assumed to benefit cold-limited invasive alien species,
these climatic changes may also change their feeding preferences, especially in the
case of omnivorous ectotherms. We investigated heat wave effects on diet choice, growth
and energy reserves in the invasive red swamp crayfish, Procambarus clarkii. In laboratory
experiments, we fed juvenile and adult crayfish on animal, plant or mixed diets and exposed
them to a short or a long heat wave. We then measured crayfish survival, growth, body
reserves and Fulton's condition index. Diet choices of the crayfish maintained on the mixed
diet were estimated using stable isotopes (13C and 15N). The results suggest a decreased
efficiency of carnivorous diets at higher temperatures, as juveniles fed on the animal diet
were unable to maintain high growth rates in the long heat wave; and a decreased efficiency
of herbivorous diets at lower temperatures, as juveniles in the cold accumulated less body
reserves when fed on the plant diet. Heat wave treatments increased the assimilation of
plant material, especially in juveniles, allowing them to sustain high growth rates in the long
heat wave. Contrary to our expectations, crayfish performance decreased in the long heat
wave, suggesting that Mediterranean summer heat waves may have negative effects on
P. clarkii and that they are unlikely to boost its populations in this region. Although uncertain,
it is possible that the greater assimilation of the plant diet resulted from changes in crayfish
feeding preferences, raising the hypotheses that i) heat waves may change the predominant
impacts of this keystone species and ii) that by altering species' trophic niches, climate
change may alter the main impacts of invasive alien species
Description
Research Article
Keywords
Procambarus clarkii invasive crayfish heat waves trophic role
Pedagogical Context
Citation
Carreira BM, Segurado P, Laurila A, Rebelo R (2017) Can heat waves change the trophic role of the world's most invasive crayfish? Diet shifts in Procambarus clarkii. PLoS ONE 12(9): e0183108.
Publisher
Hans G. Dam, University of Connecticut, UNITED STATES
