Can mandible morphology help predict feeding habits in Antarctic amphipods?

Abstract

In Antarctica, amphipods form a highly diverse group, occupy many different ecological niches and hold an important place in food webs. Here, we aimed to test whether differences in Antarctic amphipod feeding habits were reflected in their mandible morphology, and if mouthpart specialization could be used to describe amphipod trophic ecology. To do so, we compared mandible morphology in nine species spanning seven families and five functional groups (grazers, suspension feeders, generalist predators, specialist predators and scavengers). Mandible morphology adequately depicted some aspects of amphipod trophic ecology, such as the trophic level at which animals feed or their degree of dietary specialization. On the other hand, links between mandible morphology and amphipod diet were seldom unambiguous or straightforward. Similar adaptations were found in distinct functional groups. Conversely, mandible morphology could vary within a single functional group, and phylogenetic effects sometimes complicated the interpretation of form-function relationships. Overall, mandible morphology on its own was generally not sufficient to precisely predict amphipod feeding strategies. However, when combined with other methods (e.g. gut contents, trophic markers), it constitutes a valuable source of information for integrative studies of amphipod ecological diversity in the Southern Ocean.

The phenology of epiphytic diatoms and epifauna observed on <i>Zostera marina</i> of Arikawa Bay, Nagasaki Prefecture, Japan

“…Our study suggests that herbivores such as gastropods and amphipods could alter species composition by preferring food items (active choice) or by ingesting more of the species that were structurally more available (passive preference). In turn, food availability may influence herbivore diversity, as mouthpart morphology appears to be correlated with trophic ecology (Michel et al 2020). More conservatively, herbivory and substrate availability both serve to control the cell density of epiphytic diatoms in a Z. marina meadow (Jacobs and Noten 1980, Nelson 1997, Nakaoka et al 2001.…”

Morphology mirrors trophic niche in a freshwater amphipod community

“…The link between morphology and trophic niche is one of the most pervasive and important ones from an eco‐evolutionary perspective, providing critical insight into macroevolutionary processes (Davis et al., 2016; Pigot et al., 2020). However, the relationship between morphology and trophic niche has been studied mainly in marine amphipods (Arndt et al., 2005; Caine, 1974; Coleman, 1989, 1991; Michel et al., 2020), and comparatively little is known about freshwater taxa (Hutchins et al., 2014).…”