Exposure to moderately elevated temperatures changes food preferences in the tropical marine herbivore Haliotis squamata

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Mitterwallner, Veronika ; Suci, An Nisa Nurul ; Zamani, Neviaty ; Lenz, Mark:
Exposure to moderately elevated temperatures changes food preferences in the tropical marine herbivore Haliotis squamata.
In: Marine Biology. Bd. 168 (19 Juni 2021) Heft 7 . - No. 110.
ISSN 0025-3162
DOI: https://doi.org/10.1007/s00227-021-03922-y

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Abstract

Ocean warming is affecting marine ectothermic herbivores as well as the macroalgal species they consume and this has the potential to alter their trophic interaction. However, it is currently still unknown how these two important components of benthic food webs will react to a warming environment. Consumption rates of grazers change with increasing temperatures, but it is unclear whether this is also true for feeding preferences. In this study, multiple-choice feeding assays with the tropical abalone Haliotis squamata from Western Indonesia were conducted in August 2018. After brief acclimation of either the grazer or the macroalgae to moderately elevated water temperatures (maximum 2 °C above the long-term average) in the laboratory, three species of living macroalgae were simultaneously offered to the abalone in feeding assays. Consumption rates of H. squamata were lower under elevated water temperatures, while its feeding preference switched: At 27 °C (2 °C below long-term average), abalone preferred non-acclimated Gracilaria salicornia, but switched to non-acclimated Amphiroa spp. at 31 °C. Interestingly, no such switch in preference occurred when the macroalgae, but not the grazers were acclimated. This indicates that the grazer will presumably be the driver of this potential change in interactions between H. squamata and its macroalgal food. Ocean warming may result in changes in the structure of benthic communities, mediated by changes in the feeding behaviour of herbivorous invertebrates.