Trophic segregation in a burrow: the stable carbon and nitrogen isotope ratios of the burrowing shrimp <i>Upogebia major</i> and its commensal bivalve <i>Cryptomya busoensis</i>

Abstract

Burrows produced by marine invertebrates often harbor other small commensal invertebrates. The mud shrimp Upogebia is known to coexist with the myid bivalve Cryptomya in a burrow produced by the shrimp. Both species are filter-feeders, and thus interspecific competition or trophic niche segregation may occur in the burrow. Samples for carbon and nitrogen stable isotope analysis were collected from a tidal flat near the tidal inlet of Akkeshi Lake, Hokkaido, northern Japan in April 2013. In addition, stratified benthos sampling was conducted on the tidal flat in August 2018, to clarify the interspecific relationship between U. major and C. busoensis in the burrow. The stratified benthos sampling showed the vertical distribution of these species, and indicated that both species filter water from the same part of the burrow for feeding. The stable carbon and nitrogen isotope analysis showed that important food sources for both U. major and C. busoensis are marine phytoplankton and microphytobenthos. In addition, C. busoensis is likely to consume terrestrial organic matter whereas U. major is unable to utilize it. The partial trophic segregation between the species increases the potential benthic filtering because it allows the Upogebia burrow complex to consume a wide variety of organic matter, and it might reduce interspecific competition between the filter-feeding host and its commensal species. These results demonstrate how ecologically similar macrobenthos can coexist in a burrow.

Stable isotopes disentangle niche partitioning and species co-occurrence in a multi-level marine mutualism

“…Co-occurrence among symbionts is thus maintained via a combination of utilizing different food resources and niche breadth. In a mud-burrowing shrimp-bivalve commensalism where the burrowing shrimp provides habitat space for a co-occurring bivalve, species exhibited isotopic niche differentiation with the shrimp occupying a higher trophic level than the bivalve (Seike & Goto 2020). Finally, De Grave et al (2021) also used stable isotopes to explore the trophic levels of symbiotic crustaceans and their benthic macro-invertebrate hosts from Japan, but like Seike & Goto (2020), this work used host-symbiont pairs rather than focusing on a community of species that co-occur on the same host.…”

Life history characteristics and burrow structure of the mud shrimp (Decapoda: Upogebiidae)

“…The shrimpsʼ activities have a variety of impacts on the abiotic environment of their habitat (Kinoshita et al 2003a, Sasaki et al 2014, Das et al 2017) and can affect local benthic communities (Pillay & Branch 2011), creating spaces for other organisms (MacGinitie 1935, Atkinson & Taylor 2005, Dworschak et al 2012, Tseng et al 2019. Such burrow inhabitants are well studied in Japan (Sato et al 2001, Itoh & Nishida 2002, Kinoshita 2002, 2017, Shiozaki & Itani 2020, Seike & Goto 2020. Information on thalassinid burrow-dwelling shrimps is particularly abundant (Atkinson & Eastman 2015), as mud shrimps contribute to fishery resources.…”