Filter-feeding behavior of three Asian Hediste species (Polychaeta: Nereididae)

Abstract

Abstract:The three Hediste species H. japonica, H. diadroma and H. atoka (Polychaeta: Nereididae) live in burrows in estuarine intertidal flats in eastern Asia and have been regarded as surface deposit feeders. Their filter-feeding behavior was investigated in laboratory experiments where the worms were placed in a U-shaped glass tube. The behavior is basically the same among the three species and the same as that previously observed in H. diversicolor inhabiting Atlantic coasts and consists of the following four steps: (1) Moving up to the end of the tube; (2) retreating slowly down, with the anterior body expanded laterally and moving from side to side in semicircles, making a transparent, funnel-shaped mucous net; (3) orientation of the head at 2.5-6.0 cm below the end of the glass tube, and pumping water through the net by means of active undulating movements of the body for 1-5 min; (4) moving forward and swallowing the mucous net together with the trapped particles. This behavior is accelerated by adding organic particles to the seawater. Such facultative filter feeding is judged as a unique generic characteristic of Hediste among the Nereididae and its ecological significance is discussed in relation to their estuarine habitats.

What is the menu today in a subantarctic kelp food web from the Kerguelen Islands? Phytodetritus, phytoplankton and phytobenthos; not living kelp

“…kerguelensis may consume detritus of Acrosiphonia sp. This is in line with the knowledge that Nereididae polychaetes may display either deposit (Tsuchiya and Kurihara 1979;Fong 1987) or suspension feeding behaviors (Costa et al 2006;Toba and Sato 2013), although they may also display predatory behaviors (Costa et al 2006). Sedentary polychaetes appeared to feed mostly on SPOM and resuspended sediment.…”

Effects of seasonal irrigation subsidies on the dietary components of estuarine detritus feeders: stable isotopic analysis focusing on nereidid polychaetes

“…In general, H. diadroma became larger in body size than H. atoka and achieve annual largest size in spring shortly before reproductive swarming (Kikuchi & Yasuda 2006). Larger individuals of H. diadroma would have higher activity of filter-feeding than smaller individuals due to their more vigorous pumping of overlying water into the U-shaped burrows (Toba & Sato 2013). This may result in higher dietary contribution of POMs to larger individuals in the population.…”

“…The relative dietary contributions of four food sources (Fig. 4) were specific to the four feeding groups: (1) the facultative-suspension feeders Hediste diadroma and H. atoka that occasionally switch from suspension to surfacedeposit feeding (Toba & Sato 2013); (2) the obligatory sus-pension feeders Exolaternula liautaudi and Corbicula japonica (Kanaya et al 2019); (3) the surface-deposit feeder Tylorrhynchus osawai (Doi et al 2005); and (4) the selective surface-deposit feeders Limecola contabulata, Macrophthalmus japonicus, and Ilyoplax pusilla (Wada 1982, Kanaya et al 2005.…”

“…2) would increase the quality of surface sediment as diet for surface-deposit feeders including Hediste species. Such opportunistic dietary shifts may be related to the plasticity of feeding modes in Hediste species, which can switch from deposit feeding to mucousbased suspension feeding when the concentration of fine organic particles in the water column increases (Toba & Sato 2013). Feeding mode flexibility among nereidid worms has only been reported in the genus Hediste (Toba & Sato 2013); this could be an adaptation to temperate estuaries where the availabilities of various food components vary both temporally and spatially.…”

“…Nereidid polychaetes, including the facultative suspension feeders Hediste atoka Sato & Nakashima, 2003 and Hediste diadroma Sato & Nakashima, 2003 and the surface-deposit feeder Tylorrhynchus osawai (Izuka, 1903) (Toba & Sato 2013, Kanaya et al 2018, are widely distributed along the Japanese coast and often dominate estuarine soft-bottom communities (Sato & Nakashima 2003, Kanaya 2017, Ministry of the Environment 2019). Our previous work showed that these organisms can assimilate a considerable fraction of river subsidies, although there are distinct spatial variations (Kanaya et al 2008b;2018;.…”