Table 1.

Chemotaxis and sperm swimming.

species	phenomenon	reference
molluscs
Sepia officinalis	species-specific sperm chemotaxis	[10]
Haliotis rufescens	species-specific sperm chemotaxis	[11]
Mytilus edulis Mytilus galloprovincialis	assortative mating through gamete preference	[12]
M. galloprovincialis	sperm chemotaxis promoting sperm–egg encounters and facilitating species recognition; chemoattractants' unforeseen role in sexual selection by enabling sperm to ‘choose’ between the eggs of different conspecific females—mediating mate choice for genetically compatible partners	[9]
M. galloprovincialis	egg chemoattraction also promotes changes in sperm behaviour and physiology; gamete ‘preferences’—sperm from individual males consistently swim towards (and fertilize) the eggs of certain females	[13]
other invertebrate broadcast spawners
	sperm chemotaxis—attractants and stimulators of sperm motility and respiration	[14]
	chemotactic signalling of sperm from marine invertebrates—sperm adjust their swimming path in a gradient of a chemical factor released by the egg	[15]
	species-specific sperm chemotaxis—preventing crossbreeding, especially in marine invertebrates with external fertilization	[16]
Strongylocentrotus purpuratus	speract: egg peptide that regulates sperm motility and stimulates sperm mitochondrial metabolism	[17]