The Physiology of Sponge Behavior

Publication Date

1-1-2024

Document Type

Contribution to a Book

Publication Title

Frontiers in Invertebrate Physiology: A Collection of Reviews: Volume 1: Non-Bilaterian Phyla

Volume

1

DOI

10.1201/9781003403319-2

First Page

65

Last Page

128

Abstract

Sponges (Porifera) are benthic suspension feeders that are of importance to aquatic system functioning because of their vast filtration capacity and their role as habitat formers. Increasingly the role of sponge behavior is also being recognized because it changes how sponges filter and thereby their wellbeing and ecological roles. Sponges lack neurons, gap junctions or synapses; rapid behavior is only known in glass sponges which can propagate electrical signals along syncytial tissues to arrest the feeding current. Glass sponges are syncytial; all others are cellular and yet all sponges share similar slow contractions of their aquiferous system. Contractions are rhythmic and in response to specific mechanical and chemical stimuli. The timing of rhythmic contractions depends upon the size of the sponge and type of aquiferous system, ranging from as ‘fast’ as 40 minutes for submillimeter sized sponges, to an hour for millimeter sized, half a day for fist-sized sponges and several days for larger sponges. Deep sea glass sponges take from a day to nearly a week to contract and expand. For cellular sponges the tissues involved are endopinacoderm of subdermal space, canals, ostia, and osculum. Evidence suggests the osculum is the common sensory organ but responses differ by species and habitat, with some that are accustomed to constant current responding to slow water, and others accustomed to still or slow moving water responding to current, usually by constricting oscula 66and canals. Many species are sensitive to sudden changes in the temperature, turbidity, and the chemical environment. Signaling molecules may include glutamate, with modulation by nitric oxide (NO), GABA, ATP, and cAMP which may prevent uncoordinated responses. Specifics of signaling and location of receptors are still unknown. Other behaviors by sponges include crawling/translocation, larval swimming in response to light and orientation, and settlement. Despite over a century of work, sponge behavior is only beginning to be understood beyond our bilaterian lens and areas that merit new or renewed investigation are highlighted.

Keywords

electrical signaling, pH, Porifera, signaling molecules, sponges, subdermal space

Department

Computer Science

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