Exploring the role of macroalgal traits on the feeding behaviour of a generalist herbivore in Malaysian waters

Abstract

With the potential adverse effects of climate change, it is essential to enhance the understanding of marine ecosystem dynamics, which can be driven by the co-evolutionary interaction between autotrophs and herbivores. This study looked into the autotroph-herbivore interactions in Malaysian waters, mainly to determine if autotroph nutritional quality significantly influences herbivore consumption rates. We documented the relative consumption rate of a generalist herbivore (Chanos chanos Forsskål) obtained from the Straits of Malacca through multiple feeding trials using 12 macroalgal species collected from different coastal areas of the Straits of Malacca, the Straits of Johor, and the South China Sea. The herbivore fed selectively on the tested macroalgal species, with the most and least consumed species having the lowest and highest total nitrogen content, respectively. Besides total nitrogen content, the least consumed species also had the highest total phenolic content. Interestingly, we observed that the herbivore generally preferred to consume filamentous macroalgae, especially those collected from the South China Sea. Overall, our findings demonstrated that the feeding behaviour of a generalist herbivore could be influenced by the nutritional quality of the autotrophs, which may depend directly or indirectly on other factors such as autotroph morphology and geography.

Marine Autotroph-Herbivore Synergies: Unravelling the Roles of Macroalgae in Marine Ecosystem Dynamics

“…Living organisms require nitrogen to synthesize amino acids, the basic building blocks of protein that serve essential functions in virtually all biological processes [ 153 ]. Many previous studies have pointed out that low nitrogen consumption is associated with reduced food intake in generalist marine herbivores [ 39 , 148 , 160 , 161 , 162 , 163 ]. The study by Barile, Lapointe and Capo [ 156 ] on California sea hare ( Aplysia californica ) showed that this herbivorous gastropod preferred to feed on gracilarioid algae ( Gracilaria ferox ) with high levels of nitrogen.…”

“…The lack of preference for protein-enriched algae (i.e., high-nutrient algae) can be explained by the compensatory feeding behaviour of some herbivore species. Previous studies reported the optimal growth rate and adequate intakes of limiting nutrients by testing the consumption rates of different herbivores on the low nutritional quality of algae foods [ 39 , 43 , 164 , 165 ]. According to Bradley et al (2021), herbivores may avoid species that are less palatable or have lower nutritional value, which may affect their distribution and abundance [ 164 ].…”

“…One hundred and seven papers have been validated and reviewed comprehensively. At present, the available literature on the interactions between autotroph palatability and their various attributes on the nutritional ecology of marine herbivores is scattered and fragmentary [ 39 , 40 , 41 ]. It is also important to note that the chemical compounds in autotrophs that attract or deter their feeders are not well-addressed [ 42 , 43 ].…”