Salp chains

@article{peterson1953basic,
    author = "Peterson, Gordon E.",
    title = "Basic Physical Systems For Communication Between Two Individuals",
    year = "1953",
    journal = "Journal of Speech and Hearing Disorders",
    url = "https://doi.org/10.1044/jshd.1802.116",
    doi = "10.1044/jshd.1802.116",
    number = "2",
    pages = "116-120",
    volume = "18"
}

When stimulated, salp chains achieve rapid coordinated changes in locomotion by the spread of epithelial action potentials or outer skin pulses (o. s. ps) from one zooid to the next along the chain. This process involves alternating epithelioneural and neuroepithelial chemical synapses. Each zooid is linked to another in the chain by two asymmetric attachment plaques; these are polarized so that transmission of o. s. ps proceeds from one zooid to the next in one direction at one plaque, and in the reverse direction at the other plaque. Sensory cells at the plaques send axons to the brain; they are not electrically coupled to the conducting epithelium in which they lie. Input from the plaque sensory cells affects the swimming generator in the brain (causing locomotor changes) and evokes synaptic activity at neuroepithelial synapses around the brain. This gives rise to o. s. ps that are conducted around the whole of the outer epithelium of the zooid and are detected at the plaques by the sensory cells of adjacent zooids. Severe stimulation of a zooid in the chain induces all zooids to separate; possible mechanisms of separation are discussed.

@article{anderson1980communication,
    author = "Anderson, P. A. V. and Bone, Quentin",
    title = "Communication between individuals in salp chains. II. Physiology",
    year = "1980",
    journal = "Proceedings of the Royal Society of London. Series B. Biological Sciences",
    abstract = "When stimulated, salp chains achieve rapid coordinated changes in locomotion by the spread of epithelial action potentials or outer skin pulses (o. s. ps) from one zooid to the next along the chain. This process involves alternating epithelioneural and neuroepithelial chemical synapses. Each zooid is linked to another in the chain by two asymmetric attachment plaques; these are polarized so that transmission of o. s. ps proceeds from one zooid to the next in one direction at one plaque, and in the reverse direction at the other plaque. Sensory cells at the plaques send axons to the brain; they are not electrically coupled to the conducting epithelium in which they lie. Input from the plaque sensory cells affects the swimming generator in the brain (causing locomotor changes) and evokes synaptic activity at neuroepithelial synapses around the brain. This gives rise to o. s. ps that are conducted around the whole of the outer epithelium of the zooid and are detected at the plaques by the sensory cells of adjacent zooids. Severe stimulation of a zooid in the chain induces all zooids to separate; possible mechanisms of separation are discussed.",
    url = "https://doi.org/10.1098/rspb.1980.0153",
    doi = "10.1098/rspb.1980.0153",
    number = "1181",
    pages = "559-574",
    volume = "210"
}

The plaque consists on one side of a small button of modified epithelial cells (plate 1, 5 and 6) and on the other of a small group of sensory cells, which are less conspicuous than the button cells. At the light microscope level, the button cells can be seen to form a sort of small button or mushroom protuding from the epithelium of the plaque (plate 1, 11 and 12; figure 2) into the test material separating the two epithelial layers. Opposite this button are a group of sensory cells, the axons of which pass to the brain shrouded in the bases of the epithelial cells (plate 1, 8 and 9). The arrangement of the button cells and opposing sensory cells is a constant one, so that, on a single zooid, one of the pair of plaques joining it to an adjacent zooid has a group of sensory cells, the other (the non-innervated plaque), a group of button cells. The plaques at the outer ends of the horns are innervated, as are those near the horn bases, while those on the ventral surface and at the inner end of the horns are not innervated, and have the button cells. In consequence of this, it is a simple matter to separate one or other of the plaques joining two zooids to investigate their physiological properties (Anderson & Bone 1980). Fedele (1920) first described the sensory cells of the attachment plaques, but he supposed that they occurred at both sides in each plaque. In fact, they lie only on one side of the plaque, as described above, and this asymmetry has important consequences for the way in which the system operates. Apart from the specialized region of the plaque, where these cells are found, the plaque is symmetrical, and the two epithelial layers are some 5 μm apart, separated by test material (plate 1, 7). The epithelial cells are flattened (like those of the outer epithelium outside the plaques), and are some 2–5 pm thick (plate 2, 1). They contain an extensive smooth endoplasmic reticulum, mitochondria with tubular cristae, flattened nuclei, and occasional vesicles of various sizes

@article{bone1980morphology,
    author = "Bone, Quentin and Anderson, P. A. V. and Pulsford, A.",
    title = "Morphology of salp chain communication",
    year = "1980",
    journal = "Proceedings of the Royal Society of London. Series B. Biological Sciences",
    abstract = "The plaque consists on one side of a small button of modified epithelial cells (plate 1, 5 and 6) and on the other of a small group of sensory cells, which are less conspicuous than the button cells. At the light microscope level, the button cells can be seen to form a sort of small button or mushroom protuding from the epithelium of the plaque (plate 1, 11 and 12; figure 2) into the test material separating the two epithelial layers. Opposite this button are a group of sensory cells, the axons of which pass to the brain shrouded in the bases of the epithelial cells (plate 1, 8 and 9). The arrangement of the button cells and opposing sensory cells is a constant one, so that, on a single zooid, one of the pair of plaques joining it to an adjacent zooid has a group of sensory cells, the other (the non-innervated plaque), a group of button cells. The plaques at the outer ends of the horns are innervated, as are those near the horn bases, while those on the ventral surface and at the inner end of the horns are not innervated, and have the button cells. In consequence of this, it is a simple matter to separate one or other of the plaques joining two zooids to investigate their physiological properties (Anderson \& Bone 1980). Fedele (1920) first described the sensory cells of the attachment plaques, but he supposed that they occurred at both sides in each plaque. In fact, they lie only on one side of the plaque, as described above, and this asymmetry has important consequences for the way in which the system operates. Apart from the specialized region of the plaque, where these cells are found, the plaque is symmetrical, and the two epithelial layers are some 5 μm apart, separated by test material (plate 1, 7). The epithelial cells are flattened (like those of the outer epithelium outside the plaques), and are some 2–5 pm thick (plate 2, 1). They contain an extensive smooth endoplasmic reticulum, mitochondria with tubular cristae, flattened nuclei, and occasional vesicles of various sizes",
    url = "https://doi.org/10.1098/rspb.1980.0152",
    doi = "10.1098/rspb.1980.0152",
    number = "1181",
    pages = "549-558",
    volume = "210"
}

@inproceedings{bone1980the1,
    author = "Bone, Q. and Ryan, K. P. and Anderson, P. A. V. and Pulsford, A",
    title = "The communication between individuals in salp chains 1. Morphology of the system",
    year = "1980",
    booktitle = "Proceedings of the Royal Society, London B, v. 210, p. 549-558",
    note = "talkorigins\_source = {true}; raw\_reference = {Bone, Q., Ryan, K. P., Anderson, P. A. V., and Pulsford, A., 1980, The communication between individuals in salp chains 1. Morphology of the system: Proceedings of the Royal Society, London B, v. 210, p. 549-558.}"
}

A three-part argument is made that vertical communication chains in organizations need more study. First, four fundamental questions about chained vertical communication are posited. Second, relevant literature in five sets is reviewed; the sets include superior-subordinate communication studies, role conflict studies, ethnographic case studies, studies of vertical serial transmission, and network analyses. In each set there are at least a few studies that indicate the importance of vertical chain effects on other interactional units of analysis, but the studies collectively give only fragmentary answers to the fundamental questions. Third, three alternative theoretical models of chained vertical communication—a homogeneous model, a multiple strata model, and a multiple clusters model—are explicated that make rival claims about the nature and importance of the vertical chain, claims that cannot be distinguished on the basis of the current empirical literature. The article ends with suggestions for an integrated approach to the study of vertical chains—integrated across methods and across study foci.

@article{mcphee1988vertical,
    author = "McPhee, Robert D.",
    title = "Vertical Communication Chains",
    year = "1988",
    journal = "Management Communication Quarterly",
    abstract = "A three-part argument is made that vertical communication chains in organizations need more study. First, four fundamental questions about chained vertical communication are posited. Second, relevant literature in five sets is reviewed; the sets include superior-subordinate communication studies, role conflict studies, ethnographic case studies, studies of vertical serial transmission, and network analyses. In each set there are at least a few studies that indicate the importance of vertical chain effects on other interactional units of analysis, but the studies collectively give only fragmentary answers to the fundamental questions. Third, three alternative theoretical models of chained vertical communication—a homogeneous model, a multiple strata model, and a multiple clusters model—are explicated that make rival claims about the nature and importance of the vertical chain, claims that cannot be distinguished on the basis of the current empirical literature. The article ends with suggestions for an integrated approach to the study of vertical chains—integrated across methods and across study foci.",
    url = "https://doi.org/10.1177/0893318988001004002",
    doi = "10.1177/0893318988001004002",
    number = "4",
    pages = "455-493",
    volume = "1"
}

@article{njikeh2014electromagnetic,
    author = "Njikeh, Kong Derick",
    title = "Electromagnetic Wave and Gaseous Communication between Individuals",
    year = "2014",
    journal = "Neuroscience and Medicine",
    url = "https://doi.org/10.4236/nm.2014.51004",
    doi = "10.4236/nm.2014.51004",
    number = "01",
    pages = "20-22",
    volume = "05"
}

Plants respond to volatile cues emitted by damaged neighbors to increase their defenses against herbivores. We examined whether plants communicated more effectively with local neighbors than distant neighbors in a reciprocal experiment at two sites. Three branches on focal plants were incubated with air from (1) a control, (2) an experimentally clipped “foreign” plant from 230 km away, or (3) an experimentally clipped “local” plant from the same population as the focal plant. Branches incubated with air from the controls experienced 50–80% more leaf damage than those receiving air from experimentally clipped plants. Of more interest, branches receiving volatiles from experimentally clipped “local” plants received 50–65% of the leaf damage as those receiving volatiles from experimentally clipped “foreign” plants. Sabinyl compounds and related terpinenes were found to differ consistently for plants from southern and northern sites. These results indicate that cues vary geographically in their effectiveness and suggest that sagebrush responds more strongly to local than foreign dialects.

@article{karban2016geographic,
    author = "Karban, Richard and Wetzel, William C. and Shiojiri, Kaori and Pezzola, Enrico and Blande, James D.",
    title = "Geographic dialects in volatile communication between sagebrush individuals",
    year = "2016",
    journal = "Ecology",
    abstract = "Plants respond to volatile cues emitted by damaged neighbors to increase their defenses against herbivores. We examined whether plants communicated more effectively with local neighbors than distant neighbors in a reciprocal experiment at two sites. Three branches on focal plants were incubated with air from (1) a control, (2) an experimentally clipped “foreign” plant from 230 km away, or (3) an experimentally clipped “local” plant from the same population as the focal plant. Branches incubated with air from the controls experienced 50–80\% more leaf damage than those receiving air from experimentally clipped plants. Of more interest, branches receiving volatiles from experimentally clipped “local” plants received 50–65\% of the leaf damage as those receiving volatiles from experimentally clipped “foreign” plants. Sabinyl compounds and related terpinenes were found to differ consistently for plants from southern and northern sites. These results indicate that cues vary geographically in their effectiveness and suggest that sagebrush responds more strongly to local than foreign dialects.",
    url = "https://doi.org/10.1002/ecy.1573",
    doi = "10.1002/ecy.1573",
    number = "11",
    pages = "2917-2924",
    volume = "97"
}

Salps are marine invertebrates comprising multiple jet-propelled swimming units during a colonial life-cycle stage. Using theory, we show that asynchronous swimming with multiple pulsed jets yields substantial hydrodynamic benefit due to the production of steady swimming velocities, which limit drag. Laboratory comparisons of swimming kinematics of aggregate salps (Salpa fusiformis and Weelia cylindrica) using high-speed video supported that asynchronous swimming by aggregates results in a smoother velocity profile and showed that this smoother velocity profile is the result of uncoordinated, asynchronous swimming by individual zooids. In situ flow visualizations of W. cylindrica swimming wakes revealed that another consequence of asynchronous swimming is that fluid interactions between jet wakes are minimized. Although the advantages of multi-jet propulsion have been mentioned elsewhere, this is the first time that the theory has been quantified and the role of asynchronous swimming verified using experimental data from the laboratory and the field.

@article{sutherland2017hydrodynamic,
    author = "Sutherland, Kelly R. and Weihs, Daniel",
    title = "Hydrodynamic advantages of swimming by salp chains",
    year = "2017",
    journal = "Journal of The Royal Society Interface",
    abstract = "Salps are marine invertebrates comprising multiple jet-propelled swimming units during a colonial life-cycle stage. Using theory, we show that asynchronous swimming with multiple pulsed jets yields substantial hydrodynamic benefit due to the production of steady swimming velocities, which limit drag. Laboratory comparisons of swimming kinematics of aggregate salps (Salpa fusiformis and Weelia cylindrica) using high-speed video supported that asynchronous swimming by aggregates results in a smoother velocity profile and showed that this smoother velocity profile is the result of uncoordinated, asynchronous swimming by individual zooids. In situ flow visualizations of W. cylindrica swimming wakes revealed that another consequence of asynchronous swimming is that fluid interactions between jet wakes are minimized. Although the advantages of multi-jet propulsion have been mentioned elsewhere, this is the first time that the theory has been quantified and the role of asynchronous swimming verified using experimental data from the laboratory and the field.",
    url = "https://doi.org/10.1098/rsif.2017.0298",
    doi = "10.1098/rsif.2017.0298",
    number = "133",
    pages = "20170298",
    volume = "14"
}

@article{aljarah2018asynchronous,
    author = "Aljarah, Ibrahim and Mafarja, Majdi and Heidari, Ali Asghar and Faris, Hossam and Zhang, Yong and Mirjalili, Seyedali",
    title = "Asynchronous accelerating multi-leader salp chains for feature selection",
    year = "2018",
    journal = "Applied Soft Computing",
    url = "https://doi.org/10.1016/j.asoc.2018.07.040",
    doi = "10.1016/j.asoc.2018.07.040",
    pages = "964-979",
    volume = "71"
}

@article{zhang2019chaosinduced,
    author = "Zhang, Qian and Chen, Huiling and Heidari, Ali Asghar and Zhao, Xuehua and Xu, Yingying and Wang, Pengjun and Li, Yuping and Li, Chengye",
    title = "Chaos-Induced and Mutation-Driven Schemes Boosting Salp Chains-Inspired Optimizers",
    year = "2019",
    journal = "IEEE Access",
    url = "https://doi.org/10.1109/access.2019.2902306",
    doi = "10.1109/access.2019.2902306",
    pages = "31243-31261",
    volume = "7"
}

@article{vieira2025communication,
    author = "Vieira, Vinicius and Godoy, Arnaldo Jose",
    title = "Communication between different individuals' occipital lobes",
    year = "2025",
    journal = "Journal of the Neurological Sciences",
    url = "https://doi.org/10.1016/j.jns.2025.124940",
    doi = "10.1016/j.jns.2025.124940",
    pages = "124940",
    volume = "480"
}