Neurobiological and behavioural responses of cleaning mutualisms to ocean warming and acidification

• Published in: Scientific reports Vol. 9; no. 1; pp. 12728 - 10
• Main Authors: Paula, José Ricardo, Repolho, Tiago, Pegado, Maria Rita, Thörnqvist, Per-Ove, Bispo, Regina, Winberg, Svante, Munday, Philip L., Rosa, Rui
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04-09-2019; Nature Publishing Group
• Subjects: 631/158/856; 631/378/3919; 704/106/694/2739; 704/829/826; Acclimation; Acclimatization; Acidification; Animals; Behavior, Animal; Cleaning behavior; Cooperative Behavior; Coral Reefs; Dopamine; Dopamine receptors; Ecophysiology; Ecosystem; Ectoparasites; Fishes - physiology; Forebrain; Humanities and Social Sciences; Hydrogen-Ion Concentration; Labroides dimidiatus; Motivation; multidisciplinary; Mutualism; Naso elegans; Neurobiology; Ocean warming; Science; Science (multidisciplinary); Seawater - chemistry; Serotonin; Serotonin - metabolism; Symbiosis; Tactile stimuli; Temperature
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-49086-0

Cleaning interactions are textbook examples of mutualisms. On coral reefs, most fishes engage in cooperative interactions with cleaners fishes, where they benefit from ectoparasite reduction and ultimately stress relief. Furthermore, such interactions elicit beneficial effects on clients’ ecophysiology. However, the potential effects of future ocean warming (OW) and acidification (OA) on these charismatic associations are unknown. Here we show that a 45-day acclimation period to OW (+3 °C) and OA (980 μatm pCO
2
) decreased interactions between cleaner wrasses (
Labroides dimidiatus
) and clients (
Naso elegans
). Cleaners also invested more in the interactions by providing tactile stimulation under OA. Although this form of investment is typically used by cleaners to prolong interactions and reconcile after cheating, interaction time and client jolt rate (a correlate of dishonesty) were not affected by any stressor. In both partners, the dopaminergic (in all brain regions) and serotoninergic (forebrain) systems were significantly altered by these stressors. On the other hand, in cleaners, the interaction with warming ameliorated dopaminergic and serotonergic responses to OA. Dopamine and serotonin correlated positively with motivation to interact and cleaners interaction investment (tactile stimulation). We advocate that such neurobiological changes associated with cleaning behaviour may affect the maintenance of community structures on coral reefs.