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Trivalairat P, Trivalairat K, Tassamakorn A, Purivirojkul W. Blood recovery of wild Mekong snail-eating turtles ( Malayemys subtrijuga Schlegel and Müller, 1845) in captivity from leech infestation. Int J Parasitol Parasites Wildl 2023; 22:126-135. [PMID: 37854273 PMCID: PMC10579961 DOI: 10.1016/j.ijppaw.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/28/2023] [Accepted: 10/02/2023] [Indexed: 10/20/2023]
Abstract
Blood cell counts are valuable diagnostic tools for assessing the health status of chelonians, however, reference standards for healthy blood parameters in various turtle species are lacking. In this study, forty wild female Malayemys subtrijuga were captured from ponds in Kasetsart University, and transported to laboratory for recuperating in captivity. All turtles were infected with a single leech species, Placobdelloides siamensis, with a mean of 513.7 ± 164.9 individuals per turtle, and exhibited penetrating and lesion wounds from leech infestations on both their skin and shell. Subsequently, they were cleaned and treated to eliminate ecto- and endoparasites before the recuperation period began. The turtles did not exhibit significantly differences in weight, carapace length (CL), red blood cell count (RCC), and white blood cell count (WCC) with a mean of 654.2 ± 199.9 g, 15.0 ± 2.5 cm, 327,080 ± 70,156 cells/mm3, and 73,340 ± 15,859 cells/mm3, respectively, during the initial records (week 0). However, after being maintained for 17 weeks, their health significantly improved in term of their blood parameters (RCC and WCC) and weight, except CL which remained unchanged, with a mean of 491,470 ± 16,169 cells/mm3, 18,790 ± 1496 cells/mm3, and 738.9 ± 191.5 g, respectively. Therefore, the health status obtained in this study can be used as a reference for blood parameters, weight, and recuperation period for the treatment of ill wild M. subtrijuga in captivity or as part of conservation management programs for turtles.
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Affiliation(s)
- Poramad Trivalairat
- Chulabhorn Royal Academy, 906 Thung Song Hong, Lak Si, Bangkok, 10210, Thailand
- Animal Systematics and Ecology Speciality Research Unit (ASESRU), Department of Zoology, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
| | - Krittiya Trivalairat
- Animal Systematics and Ecology Speciality Research Unit (ASESRU), Department of Zoology, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Department of Pathology, Faculty of Medicine Siriraj Hospital, Bangkok, 10700, Thailand
| | - Awirut Tassamakorn
- Chulabhorn Royal Academy, 906 Thung Song Hong, Lak Si, Bangkok, 10210, Thailand
| | - Watchariya Purivirojkul
- Animal Systematics and Ecology Speciality Research Unit (ASESRU), Department of Zoology, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Chatuchak, Bangkok, 10900, Thailand
- Biodiversity Center, Kasetsart University (BDCKU), Bangkok, 10900, Thailand
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2
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Taylor LA, Cross FR, Jackson RR. Blood-red colour as a prey choice cue for mosquito specialist predators. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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3
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Groves TKH, Jellies JA. Spectral responses across a dorsal-ventral array of dermal sensilla in the medicinal leech. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:715-727. [PMID: 34477962 PMCID: PMC8568864 DOI: 10.1007/s00359-021-01508-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/15/2021] [Accepted: 08/27/2021] [Indexed: 11/05/2022]
Abstract
How do animals use visual systems to extract specific features of a visual scene and respond appropriately? The medicinal leech, Hirudo verbana, is a predatory, quasi-amphibious annelid with a rich sensorium that is an excellent system in which to study how sensory cues are encoded, and how key features of visual images are mapped into the CNS. The leech visual system is broadly distributed over its entire body, consisting of five pairs of cephalic eyecups and seven segmentally iterated pairs of dermal sensilla in each mid-body segment. Leeches have been shown to respond behaviorally to both green and near ultraviolet light (UV, 365–375 nm). Here, we used electrophysiological techniques to show that spectral responses by dermal sensilla are mapped across the dorsal–ventral axis, such that the ventral sensilla respond strongly to UV light, while dorsal sensilla respond strongly to visible light, broadly tuned around green. These results establish how key features of visual information are initially encoded by spatial mapping of photo-response profiles of primary photoreceptors and provide insight into how these streams of information are presented to the CNS to inform behavioral responses.
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Affiliation(s)
- Thomas K H Groves
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, 49008, USA
| | - John A Jellies
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, 49008, USA.
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Kuo DH, De-Miguel FF, Heath-Heckman EAC, Szczupak L, Todd K, Weisblat DA, Winchell CJ. A tale of two leeches: Toward the understanding of the evolution and development of behavioral neural circuits. Evol Dev 2020; 22:471-493. [PMID: 33226195 DOI: 10.1111/ede.12358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022]
Abstract
In the animal kingdom, behavioral traits encompass a broad spectrum of biological phenotypes that have critical roles in adaptive evolution, but an EvoDevo approach has not been broadly used to study behavior evolution. Here, we propose that, by integrating two leech model systems, each of which has already attained some success in its respective field, it is possible to take on behavioral traits with an EvoDevo approach. We first identify the developmental changes that may theoretically lead to behavioral evolution and explain why an EvoDevo study of behavior is challenging. Next, we discuss the pros and cons of the two leech model species, Hirudo, a classic model for invertebrate neurobiology, and Helobdella, an emerging model for clitellate developmental biology, as models for behavioral EvoDevo research. Given the limitations of each leech system, neither is particularly strong for behavioral EvoDevo. However, the two leech systems are complementary in their technical accessibilities, and they do exhibit some behavioral similarities and differences. By studying them in parallel and together with additional leech species such as Haementeria, it is possible to explore the different levels of behavioral development and evolution.
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Affiliation(s)
- Dian-Han Kuo
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Francisco F De-Miguel
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, México City, México
| | | | - Lidia Szczupak
- Departamento de Fisiología Biología Molecular y Celular, Universidad de Buenos Aires, and IFIBYNE UBA-CONICET, Buenos Aires, Argentina
| | - Krista Todd
- Department of Neuroscience, Westminster College, Salt Lake City, Utah, USA
| | - David A Weisblat
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Christopher J Winchell
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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5
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Stowasser A, Stahl A, Benoit JB, Wagenaar DA. Electrophysiology and transcriptomics reveal two photoreceptor classes and complex visual integration in Hirudo verbana. ACTA ACUST UNITED AC 2019; 222:jeb.201764. [PMID: 31262786 DOI: 10.1242/jeb.201764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/22/2019] [Indexed: 11/20/2022]
Abstract
Among animals with visual processing mechanisms, the leech Hirudo verbana is a rare example in which all neurons can be identified. However, little is known about its visual system, which is composed of several pigmented head eyes and photosensitive non-pigmented sensilla that are distributed across its entire body. Although several interneurons are known to respond to visual stimuli, their response properties are poorly understood. Among these, the S-cell system is especially intriguing: it is multimodal, spans the entire body of the leech and is thought to be involved in sensory integration. To improve our understanding of the role of this system, we tested its spectral sensitivity, spatial integration and adaptation properties. The response of the S-cell system to visual stimuli was found to be strongly dependent on the size of the area stimulated, and adaptation was local. Furthermore, an adaptation experiment demonstrated that at least two color channels contributed to the response, and that their contribution was dependent on the adaptation to the background. The existence of at least two color channels was further supported by transcriptomic evidence, which indicated the existence of at least two distinct groups of putative opsins for leeches. Taken together, our results show that the S-cell system has response properties that could be involved in the processing of spatial and color information of visual stimuli. We propose the leech as a novel system to understand visual processing mechanisms with many practical advantages.
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Affiliation(s)
- Annette Stowasser
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Aaron Stahl
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA.,Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Daniel A Wagenaar
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA .,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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6
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Kim RC, Le D, Ma K, Heath-Heckman EAC, Whitehorn N, Kristan WB, Weisblat DA. Behavioral analysis of substrate texture preference in a leech, Helobdella austinensis. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:191-202. [PMID: 30721348 DOI: 10.1007/s00359-019-01317-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/18/2019] [Accepted: 01/22/2019] [Indexed: 01/02/2023]
Abstract
Leeches in the wild are often found on smooth surfaces, such as vegetation, smooth rocks or human artifacts such as bottles and cans, thus exhibiting what appears to be a "substrate texture preference". Here, we have reproduced this behavior under controlled circumstances, by allowing leeches to step about freely on a range of silicon carbide substrates (sandpaper). To begin to understand the neural mechanisms underlying this texture preference behavior, we have determined relevant parameters of leech behavior both on uniform substrates of varying textures, and in a behavior choice paradigm in which the leech is confronted with a choice between rougher and smoother substrate textures at each step. We tested two non-exclusive mechanisms which could produce substrate texture preference: (1) a Differential Diffusion mechanism, in which a leech is more likely to stop moving on a smooth surface than on a rough one, and (2) a Smoothness Selection mechanism, in which a leech is more likely to attach its front sucker (prerequisite for taking a step) to a smooth surface than to a rough one. We propose that both mechanisms contribute to the texture preference exhibited by leeches.
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Affiliation(s)
- Rachel C Kim
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA
| | - Dylan Le
- Division of Biological Sciences, University of California San Diego, 3119 Pacific Hall, La Jolla, CA, 92093, USA
| | - Kenny Ma
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA
| | - Elizabeth A C Heath-Heckman
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Nathan Whitehorn
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - William B Kristan
- Division of Biological Sciences, University of California San Diego, 3119 Pacific Hall, La Jolla, CA, 92093, USA
| | - David A Weisblat
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA.
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7
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Northcutt AJ, Fischer EK, Puhl JG, Mesce KA, Schulz DJ. An annotated CNS transcriptome of the medicinal leech, Hirudo verbana: De novo sequencing to characterize genes associated with nervous system activity. PLoS One 2018; 13:e0201206. [PMID: 30028871 PMCID: PMC6054404 DOI: 10.1371/journal.pone.0201206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/10/2018] [Indexed: 11/19/2022] Open
Abstract
The medicinal leech is one of the most venerated model systems for the study of fundamental nervous system principles, ranging from single-cell excitability to complex sensorimotor integration. Yet, molecular analyses have yet to be extensively applied to complement the rich history of electrophysiological study that this animal has received. Here, we generated the first de novo transcriptome assembly from the entire central nervous system of Hirudo verbana, with the goal of providing a molecular resource, as well as to lay the foundation for a comprehensive discovery of genes fundamentally important for neural function. Our assembly generated 107,704 contigs from over 900 million raw reads. Of these 107,704 contigs, 39,047 (36%) were annotated using NCBI's validated RefSeq sequence database. From this annotated central nervous system transcriptome, we began the process of curating genes related to nervous system function by identifying and characterizing 126 unique ion channel, receptor, transporter, and enzyme contigs. Additionally, we generated sequence counts to estimate the relative abundance of each identified ion channel and receptor contig in the transcriptome through Kallisto mapping. This transcriptome will serve as a valuable community resource for studies investigating the molecular underpinnings of neural function in leech and provide a reference for comparative analyses.
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Affiliation(s)
- Adam J. Northcutt
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
| | - Eva K. Fischer
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Joshua G. Puhl
- Department of Entomology and Graduate Program in Neuroscience, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Karen A. Mesce
- Department of Entomology and Graduate Program in Neuroscience, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - David J. Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
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8
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Lehmkuhl AM, Muthusamy A, Wagenaar DA. Responses to mechanically and visually cued water waves in the nervous system of the medicinal leech. ACTA ACUST UNITED AC 2018; 221:221/4/jeb171728. [PMID: 29472489 DOI: 10.1242/jeb.171728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 12/05/2017] [Indexed: 11/20/2022]
Abstract
Sensitivity to water waves is a key modality by which aquatic predators can detect and localize their prey. For one such predator - the medicinal leech, Hirudo verbana - behavioral responses to visual and mechanical cues from water waves are well documented. Here, we quantitatively characterized the response patterns of a multisensory interneuron, the S cell, to mechanically and visually cued water waves. As a function of frequency, the response profile of the S cell replicated key features of the behavioral prey localization profile in both visual and mechanical modalities. In terms of overall firing rate, the S cell response was not direction selective, and although the direction of spike propagation within the S cell system did follow the direction of wave propagation under certain circumstances, it is unlikely that downstream neuronal targets can use this information. Accordingly, we propose a role for the S cell in the detection of waves but not in the localization of their source. We demonstrated that neither the head brain nor the tail brain are required for the S cell to respond to visually cued water waves.
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Affiliation(s)
- Andrew M Lehmkuhl
- University of Cincinnati, Department of Biological Sciences, Cincinnati, OH 45221, USA
| | - Arunkumar Muthusamy
- University of Cincinnati, Department of Biological Sciences, Cincinnati, OH 45221, USA
| | - Daniel A Wagenaar
- University of Cincinnati, Department of Biological Sciences, Cincinnati, OH 45221, USA .,California Institute of Technology, Division of Biology and Biological Engineering, Pasadena, CA 91125, USA
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9
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Nataf S. Autoimmunity as a Driving Force of Cognitive Evolution. Front Neurosci 2017; 11:582. [PMID: 29123465 PMCID: PMC5662758 DOI: 10.3389/fnins.2017.00582] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022] Open
Abstract
In the last decades, increasingly robust experimental approaches have formally demonstrated that autoimmunity is a physiological process involved in a large range of functions including cognition. On this basis, the recently enunciated “brain superautoantigens” theory proposes that autoimmunity has been a driving force of cognitive evolution. It is notably suggested that the immune and nervous systems have somehow co-evolved and exerted a mutual selection pressure benefiting to both systems. In this two-way process, the evolutionary-determined emergence of neurons expressing specific immunogenic antigens (brain superautoantigens) has exerted a selection pressure on immune genes shaping the T-cell repertoire. Such a selection pressure on immune genes has translated into the emergence of a finely tuned autoimmune T-cell repertoire that promotes cognition. In another hand, the evolutionary-determined emergence of brain-autoreactive T-cells has exerted a selection pressure on neural genes coding for brain superautoantigens. Such a selection pressure has translated into the emergence of a neural repertoire (defined here as the whole of neurons, synapses and non-neuronal cells involved in cognitive functions) expressing brain superautoantigens. Overall, the brain superautoantigens theory suggests that cognitive evolution might have been primarily driven by internal cues rather than external environmental conditions. Importantly, while providing a unique molecular connection between neural and T-cell repertoires under physiological conditions, brain superautoantigens may also constitute an Achilles heel responsible for the particular susceptibility of Homo sapiens to “neuroimmune co-pathologies” i.e., disorders affecting both neural and T-cell repertoires. These may notably include paraneoplastic syndromes, multiple sclerosis as well as autism, schizophrenia and neurodegenerative diseases. In the context of this theoretical frame, a specific emphasis is given here to the potential evolutionary role exerted by two families of genes, namely the MHC class II genes, involved in antigen presentation to T-cells, and the Foxp genes, which play crucial roles in language (Foxp2) and the regulation of autoimmunity (Foxp3).
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Affiliation(s)
- Serge Nataf
- CarMeN Laboratory, Bank of Tissues and Cells, Institut National de la Santé et de la Recherche Médicale 1060, INRA 1397, INSA Lyon, Lyon University Hospital (Hospices Civils de Lyon), Université Claude Bernard Lyon-1, Lyon, France
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10
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Gordy MA, Locke SA, Rawlings TA, Lapierre AR, Hanington PC. Molecular and morphological evidence for nine species in North American Australapatemon (Sudarikov, 1959): a phylogeny expansion with description of the zygocercous Australapatemon mclaughlini n. sp. Parasitol Res 2017. [PMID: 28623502 DOI: 10.1007/s00436-017-5523-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Zygocercous (aggregating) cercarial larvae were recently discovered emerging from a physid snail during a molecular survey of cercariae from molluscs in lakes in central Alberta, Canada. This manuscript delves into the characterization of these cercariae through morphological and molecular techniques and provides the first genetic information for a zygocercous larval trematode. Analyses of cytochrome c oxidase I of mitochondrial DNA and two partial regions of nuclear ribosomal DNA sequences revealed the zygocercous cercariae to belong to the genus Australapatemon Sudarikov, 1959. Further analyses of sequences of Australapatemon burti (Miller, 1923), from cercariae and adults collected from across North America, indicate a complex of nine genetically-distinct lineages within this species, a surprising level of diversity. The zygocercous cercariae, along with adult worms collected from ducks in Manitoba, Canada, and from Mexico, represent one of these lineages, and are herein described as Australapatemon mclaughlini n. sp. Seven lineages cannot yet be identified, but one is tentatively identified as Australapatemon burti.
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Affiliation(s)
- Michelle A Gordy
- University of Alberta School of Public Health, 357F South Academic Building, Edmonton, AB, T6G 2G7, Canada
| | - Sean A Locke
- Department of Biology, University of Puerto Rico at Mayagüez, Box 9000, Mayagüez, 00681-9000, Puerto Rico
| | - Timothy A Rawlings
- Department of Biology, Cape Breton University, 1250 Grand Lake Road, PO Box 5300, Sydney, NS, B1P 6L2, Canada
| | - Angela R Lapierre
- Department of Biology, Concordia University, 7141 Sherbrooke West, Montreal, QC, H4B 1R6, Canada
| | - Patrick C Hanington
- University of Alberta School of Public Health, 357F South Academic Building, Edmonton, AB, T6G 2G7, Canada.
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11
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Locomotor and energetic consequences of behavioral thermoregulation in the sanguivorous leech Hirudo verbana. J Therm Biol 2017; 65:1-7. [PMID: 28343561 DOI: 10.1016/j.jtherbio.2017.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/19/2017] [Accepted: 01/21/2017] [Indexed: 11/22/2022]
Abstract
Medicinal leeches (Hirudo verbana) thermoregulate with respect to their sanguivorous feeding behavior. Immediate postprandial preferences are for warmer than their initial acclimation temperature (Ta, 21°C, Petersen et al. 2011), while unfed leeches have a lower preferred temperature (Tpref, 12.5°C). This may reduce energy expenditure and defer starvation if feeding opportunities are limited. Energetic benefits may have an associated cost if low temperatures reduce mobility and the ability to locate further hosts. These costs could be limited if mobility is unimpaired at low temperatures, or if acclimation can restore locomotor performance to the levels at Ta. The transition from Ta to the unfed Tpref significantly reduced speed and propulsive cycle frequency during swimming, and extension and retraction rates during crawling. Aerobic metabolic rate was also reduced from 0.20±0.03Wkg-1 at Ta to 0.10±0.03Wkg-1 at Tpref. The Q10 values of 1.7-2.9 for energetic and swimming parameters indicate a substantial temperature effect, although part of the decline in swimming performance can be attributed to temperature-related changes in water viscosity. 6 weeks at Ta resulted in no detectable acclimation in locomotor performance or aerobic metabolism. The energetic savings associated with a lower Tpref in unfed leeches effectively doubled the estimated time until depletion of energy reserves. Given that some mobility is still retained at Tpref, and that acclimation is in itself costly, the energetic benefits of selecting cooler temperatures between feedings may outweigh the costs associated with reduced locomotor performance.
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12
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Adamatzky A. On exploration of geometrically constrained space by medicinal leeches Hirudo verbana. Biosystems 2015; 130:28-36. [PMID: 25766395 DOI: 10.1016/j.biosystems.2015.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/04/2015] [Accepted: 02/07/2015] [Indexed: 11/28/2022]
Abstract
Leeches are fascinating creatures: they have simple modular nervous circuitry yet exhibit a rich spectrum of behavioural modes. Leeches could be ideal blue-prints for designing flexible soft robots which are modular, multi-functional, fault-tolerant, easy to control, capable for navigating using optical, mechanical and chemical sensorial inputs, have autonomous inter-segmental coordination and adaptive decision-making. With future designs of leech-robots in mind we study how leeches behave in geometrically constrained spaces. Core results of the paper deal with leeches exploring a row of rooms arranged along a narrow corridor. In laboratory experiments we find that rooms closer to ends of the corridor are explored by leeches more often than rooms in the middle of the corridor. Also, in series of scoping experiments, we evaluate leeches capabilities to navigating in mazes towards sources of vibration and chemo-attraction. We believe our results lay foundation for future developments of robots mimicking behaviour of leeches.
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Affiliation(s)
- Andrew Adamatzky
- Unconventional Computing Centre and Bristol Robotics Lab, University of the West of England, UK
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13
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Jellies J. Which way is up? Asymmetric spectral input along the dorsal-ventral axis influences postural responses in an amphibious annelid. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:923-38. [PMID: 25152938 DOI: 10.1007/s00359-014-0935-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/14/2014] [Indexed: 11/24/2022]
Abstract
Medicinal leeches are predatory annelids that exhibit countershading and reside in aquatic environments where light levels might be variable. They also leave the water and must contend with terrestrial environments. Yet, leeches generally maintain a dorsal upward position despite lacking statocysts. Leeches respond visually to both green and near-ultraviolet (UV) light. I used LEDs to test the hypothesis that ventral, but not dorsal UV would evoke compensatory movements to orient the body. Untethered leeches were tested using LEDs emitting at red (632 nm), green (513 nm), blue (455 nm) and UV (372 nm). UV light evoked responses in 100 % of trials and the leeches often rotated the ventral surface away from it. Visible light evoked no or modest responses (12-15 % of trials) and no body rotation. Electrophysiological recordings showed that ventral sensilla responded best to UV, dorsal sensilla to green. Additionally, a higher order interneuron that is engaged in a variety of parallel networks responded vigorously to UV presented ventrally, and both the visible and UV responses exhibited pronounced light adaptation. These results strongly support the suggestion that a dorsal light reflex in the leech uses spectral comparisons across the dorsal-ventral axis rather than, or in addition to, luminance.
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Affiliation(s)
- John Jellies
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, 49008, USA,
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14
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Jellies J. Detection and selective avoidance of near ultraviolet radiation by an aquatic annelid: the medicinal leech. J Exp Biol 2014; 217:974-85. [PMID: 24265432 PMCID: PMC3951364 DOI: 10.1242/jeb.094243] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/12/2013] [Indexed: 01/12/2023]
Abstract
Medicinal leeches are aquatic predators that inhabit surface waters during daylight and also leave the water where they might be exposed to less screened light. Whereas the leech visual system has been shown to respond to visible light, leeches in the genus Hirudo do not appear to be as negatively phototactic as one might expect in order to avoid potential ultraviolet radiation (UVR)-induced damage. I used high intensity light emitting diodes to test the hypothesis that leeches could detect and specifically avoid near UVR (395-405 nm). Groups of unfed juvenile leeches exhibited a robust negative phototaxis to UVR, but had no behavioral response to blue or red and only a slight negative phototaxis to green and white light. Individual leeches also exhibited a vigorous negative phototaxis to UVR; responding in 100% of trials compared with modest negative responses to visible light (responding in ~8% of the trials). The responses in fed and unfed leeches were comparable for UVR stimuli. The responses depended upon the stimulus site: leeches shortened away from UV light to the head, and extended away from UV light to the tail. Electrophysiological nerve recordings showed that the cephalic eyes responded vigorously to UVR. Additionally, individual leech photoreceptors also showed strong responses to UVR, and a higher-order neuron associated with shortening and rapid behavioral responses, the S-cell, was activated by UVR, on both the head and tail. These results demonstrate that the leech can detect UVR and is able to discriminate behaviorally between UVR and visible light.
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Affiliation(s)
- John Jellies
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008, USA
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15
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Abstract
While moving through their environment, medicinal leeches stop periodically and wave their head or body back and forth. This activity has been previously described as two separate behaviors: one called ‘head movement’ and another called ‘body waving’. Here, we report that these behaviors exist on a continuum, and provide a detailed description of what we now call ‘scanning’. Scanning-related behavior has been thought to be involved in orientation; its function has never before been assessed. While previous studies suggested an involvement of scanning in social behavior, or sucker placement, our behavioral studies indicate that scanning is involved in orienting the leech towards prey stimuli. When such stimuli are present, scanning behavior is used to re-orient the leech in the direction of a prey-like stimulus. Scanning, however, occurs whether or not prey is present, but in the presence of prey-like stimuli scanning becomes localized to the stimulus origin. Most likely, this behavior helps the leech to gain a more detailed picture of its prey target. The display of scanning, regardless of the presence or absence of prey stimuli, is suggestive of a behavior that is part of an internally driven motor program, which is not released by the presence of sensory stimuli. The data herein include first steps to understanding the neural mechanisms underlying this important behavior.
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Stead N. SLOW AND STEADY WINS THE PREY FOR LEECHES. J Exp Biol 2013. [DOI: 10.1242/jeb.087460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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