title: Sprouting as a gardening strategy to obtain superior supplementary food: evidence from a seed-caching marine worm.
abstract: Only a handful of non-human animals are known to grow their own food by cultivating high-yield fungal or algal crops as staple food. Here we report an alternative strategy utilized by an omnivorous marine worm, Hediste diversicolor, to supplement its diet: gardening by sprouting seeds. In addition to having many other known feeding modes, we showed using video recordings and manipulative mesocosm experiments that this species can also behave like gardeners by deliberately burying cordgrass seeds in their burrows, which has been previously shown to reduce the loss of seeds to water. These seeds, however, are protected by the seed husk, and we used feeding experiments to show that they were not edible for H. diversicolor until they had sprouted or the seed husk had been artificially removed. Additionally, sprouts were shown to be highly nutritious, permitting higher growth rates in H. diversicolor than the low-quality basal food, detritus. We propose both a proximate cause (seed husk as a physical barrier) and ultimate cause (nutritional demand) for this peculiar feeding behavior. Our findings suggest that sprouting may be a common strategy used by seed-collecting animals to exploit nutrients from well-protected seeds.
authors.affiliation: Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, 4400AC, The Netherlands.
authors.forename: Zhenchang
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, 4400AC, The Netherlands.
authors.forename: Jim
authors.initials: J
authors.lastname: van Belzen
authors.affiliation: Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, 4400AC, The Netherlands.
authors.forename: Tao
authors.initials: T
authors.lastname: Hong
authors.affiliation: TechnoSuruga Laboratory Co., Ltd., Nagasaki 330, Shimizu-ku, Shizuoka, 424-0065, Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Kunihiro
authors.affiliation: Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, 4400AC, The Netherlands.
authors.forename: Tom
authors.initials: T
authors.lastname: Ysebaert
authors.affiliation: Marine and Coastal Systems, Deltares, 2629 HD, Delft, The Netherlands.
authors.forename: Peter M J
authors.initials: PM
authors.lastname: Herman
authors.affiliation: Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, 4400AC, The Netherlands.
authors.forename: Tjeerd J
authors.initials: TJ
authors.lastname: Bouma
mesh_terms: D000818:Animals; D005247:Feeding Behavior / Q000502:physiology; D018525:Germination / Q000502:physiology*; D011077:Polychaeta / Q000502:physiology*; D012639:Seeds / Q000502:physiology*
keywords: 
  Spartina
  ; cordgrass; gardening; ragworm; seed; seed-caching; sprout; sprouting