The Use of Chemical Cues by <i>Sargassum</i> Shrimps <i>Latreutes fucorum</i> and <i>Leander tenuicornis</i> in Establishing and Maintaining a Symbiosis with the Host <i>Sargassum</i> Algae

• Main Authors: Jaime L. Frahm, William Randy Brooks
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Diversity
• Subjects: symbiosis; <i>Sargassum</i> shrimps; chemical cues
• Online Access: https://www.mdpi.com/1424-2818/13/7/305

A mutualistic symbiosis exists between the alga <i>Sargassum</i> spp. and two shrimp species, <i>Latreutes fucorum</i> and <i>Leander tenuicornis</i>. However, little is known about how these shrimp locate and establish their host alga. Both visual and chemical cues are potentially available. A previous study has looked at both cue variables with results that are mixed. Specifically, these same shrimp species used chemical cues only when visible cues were available simultaneously. Visual cues would be presumably restricted at night, but chemical cues are potentially available continuously. This current research elaborates on the previous study to fully understand <i>Sargassum</i> shrimp chemoreception. Increases in sample sizes and both a 4-chambered and Y-maze apparatus were used to test whether the shrimp could detect <i>Sargassum</i> cues, dimethylsulfoniopropionate (DMSP) (a chemical excreted by some marine algae), and conspecific cues. Neither shrimp species showed a strong directional response to any of the chemical cues, but the <i>Sargassum</i> and DMSP cues did cause more shrimp to exhibit searching behavior. Additionally, several differences in responses between male and female shrimp were found for each cue. A lowered dilution of DMSP was also tested to determine sensitivity of <i>L. fucorum</i> shrimp to the chemical cue; although searching behavior was triggered, conclusions about quantifying the sensitivity could not be made. Overall, these results show the shrimp can detect chemical cues—in the absence of visual cues—that could affect initiating and maintaining this shrimp/algal symbiosis.