1
|
Bleckmann H. The incomparable fascination of comparative physiology: 40 years with animals in the field and laboratory. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:211-226. [PMID: 37987801 PMCID: PMC10995018 DOI: 10.1007/s00359-023-01681-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/17/2023] [Accepted: 11/06/2023] [Indexed: 11/22/2023]
Abstract
This paper is not meant to be a review article. Instead, it gives an overview of the major research projects that the author, together with his students, colleagues and collaborators, has worked on. Although the main focus of the author's work has always been the fish lateral line, this paper is mainly about all the other research projects he did or that were done in his laboratory. These include studies on fishing spiders, weakly electric fish, seals, water rats, bottom dwelling sharks, freshwater rays, venomous snakes, birds of prey, fire loving beetles and backswimmers. The reasons for this diversity of research projects? Simple. The authors's lifelong enthusiasm for animals, and nature's ingenuity in inventing new biological solutions. Indeed, this most certainly was a principal reason why Karl von Frisch and Alfred Kühn founded the Zeitschrift für vergleichende Physiologie (now Journal of Comparative Physiology A) 100 years ago.
Collapse
Affiliation(s)
- Horst Bleckmann
- Institute of Zoology, University of Bonn, Poppelsdorfer Schloss, Bonn, Germany.
| |
Collapse
|
2
|
Clark RW, Bakken GS, Reed EJ, Soni A. Pit viper thermography: the pit organ used by crotaline snakes to detect thermal contrast has poor spatial resolution. J Exp Biol 2022; 225:285597. [PMID: 36453156 DOI: 10.1242/jeb.244478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
Pit vipers detect infrared radiation by means of temperature contrasts created on their pit organ membranes. Signals from pit organs integrate with visual signals in the optic tectum, leading to the conjecture that the facial pits operate as an extension of the visual system. Because similar mechanisms underlie thermal imaging technology, imagery from thermal cameras is often used to infer how pit vipers perceive their environment. However, pit organs lack a focusing mechanism, and biophysical models predict that pit organs should have poor spatial resolution compared with thermal imaging cameras. Nevertheless, behavioral studies occasionally suggest pits may have better resolution than predicted by biophysical models, indicating that processing in the central nervous system may improve imaging. To estimate the spatial resolution of the neural image informing behavior, we recorded snake responses evoked by targets moving across backgrounds composed of two contrasting temperatures with an average temperature equal to the target temperature. An unresolved background would appear uniform; thus, the target would be detectable only if the background pattern were resolved. Western rattlesnakes (Crotalus oreganus) displayed no statistically significant responses to targets presented in front of patterned backgrounds, regardless of the temperature contrasts or spatial frequencies within the background, but responded strongly to targets presented in front of homogeneous backgrounds. We found no evidence that the pit organ system can resolve spatial details subtending an angle of 9 deg or less. We discuss the implications of these results for understanding pit organ function in ecologically relevant habitats with thermal heterogeneity.
Collapse
Affiliation(s)
- Rulon W Clark
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - George S Bakken
- Department of Biology, San Diego State University, San Diego, CA 92182, USA.,4431 East Park Avenue, Terre Haute, IN 47805, USA
| | - Evan J Reed
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Ashana Soni
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| |
Collapse
|
3
|
Bakken GS, Schraft HA, Cattell RW, Tiu DB, Clark RW. Cooler snakes respond more strongly to infrared stimuli, but we have no idea why. J Exp Biol 2018; 221:jeb.182121. [DOI: 10.1242/jeb.182121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/02/2018] [Indexed: 11/20/2022]
Abstract
The pit organ defining pit vipers (Crotalinae) contains a membrane covered with temperature receptors that detect thermal radiation from environmental surfaces. Temperature is both the environmental parameter being sensed and the mechanism by which the pit membrane detects the signal. As snakes are ectotherms, temperature also has a strong influence on neurological and locomotor responses to the signal. This study of Pacific Rattlesnakes (Crotalus oreganus) systematically examined the effect of body, target, and background temperatures on response to a moving target. We presented each snake with a moving pendulum bob regulated at a series of 6 temperatures against a uniform background regulated at one of 3 temperatures. Snake body temperatures varied from 18° to 36°C. As expected, we found stronger responses to positive contrasts (target warmer than background) than to negative contrasts, and stronger responses to greater contrasts. However, the effect of body temperature was contrary to expectations based on studies of the TRPA1 ion channel (believed to be the molecular basis for pit membrane temperature receptors) and typical thermal reaction norms for neural and motor performance. These predict (1) no response below the threshold where the TRPA1 channel opens, (2) response increasing as temperature increases, peaking near preferred body temperature, and (3) declining thereafter. Remarkably, this behavioral response decreased as body temperature increased from 18°C to 36°C, with no threshold or peak in this range. We review various possible physiological mechanisms related to body temperature proposed in the literature, but find none that can satisfactorily explain this result.
Collapse
Affiliation(s)
- George S. Bakken
- 4431 East Park Ave, Terre Haute, IN, USA
- Biology Department, San Diego State University, San Diego, CA, USA
| | - Hannes A. Schraft
- Biology Department, San Diego State University, San Diego, CA, USA
- Graduate Group in Ecology, University of California, Davis, CA, USA
| | | | - Donna B. Tiu
- Biology Department, San Diego State University, San Diego, CA, USA
| | - Rulon W. Clark
- Biology Department, San Diego State University, San Diego, CA, USA
| |
Collapse
|
4
|
Kaldenbach F, Bleckmann H, Kohl T. Responses of infrared-sensitive tectal units of the pit viper Crotalus atrox to moving objects. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:389-98. [DOI: 10.1007/s00359-016-1076-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 12/22/2015] [Accepted: 02/04/2016] [Indexed: 12/22/2022]
|
5
|
Kang K. Exceptionally high thermal sensitivity of rattlesnake TRPA1 correlates with peak current amplitude. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:318-25. [DOI: 10.1016/j.bbamem.2015.12.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/24/2015] [Accepted: 12/04/2015] [Indexed: 01/06/2023]
|
6
|
Liu Y, Chen Q, Papenfuss TJ, Lu F, Tang Y. Eye and pit size are inversely correlated in crotalinae: Implications for selection pressure relaxation. J Morphol 2015; 277:107-17. [PMID: 26442780 DOI: 10.1002/jmor.20483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 08/14/2015] [Accepted: 09/02/2015] [Indexed: 02/05/2023]
Abstract
Mate, prey, and predator recognition often depend on the integration of information from multiple sensory modalities including visual, auditory, and/or olfactory inputs. In Crotalinae, the eyes sense visible light while the pit organs detect infrared (IR) radiation. Previous studies indicate that there is significant overlap between the eye and pit sensory fields and that both senses are involved in recognition processes. This study investigated the relationships between eye and pit sizes in this taxonomic group as a function of phylogeny and habitat. In view of the fact that pit orientation depends largely on snout shape, pit vipers were grouped as follows: 1) arboreal, 2) terrestrial with rounded snout, and 3) terrestrial with pointed snout. The pit orientations and habitant patterns were fully independent of the Crotalinae phylogenetic tree. The phylogenetic generalized least squares model showed that both eye and pit areas were not of significantly phylogenetic relatedness, implying alternatively a strong effect of adaptation on eye and pit sizes. Negative correlations between relative eye and pit areas in terrestrial (both pointed and rounded snouts) and arboreal species were statistically significant. Our results suggest that the eyes and pits function in a complementary fashion such that selection for IR-perception relaxes selection pressures on the visual system and selection for visual discrimination relaxes selection pressures acting on the IR-system.
Collapse
Affiliation(s)
- Yang Liu
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Qin Chen
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Theodore J Papenfuss
- Department of Amphibians and Reptiles, Museum of Vertebrate Zoology, University of California, Berkeley, California
| | - Fang Lu
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yezhong Tang
- Department of Herpetology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| |
Collapse
|
7
|
Zhang Z, Zhang Y, Zhang Q, Cheng T, Wu X. Bionic research of pit vipers on infrared imaging. OPTICS EXPRESS 2015; 23:19299-19317. [PMID: 26367591 DOI: 10.1364/oe.23.019299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The members of viperidae crotalinae (pit viper) family have special pit organs to detect infrared radiation in normal room conditions, whereas most artificial uncooled infrared focal plane arrays (FPAs) operate only in a vacuum chamber. Dissection shows that the pit membrane is a unique substrate-free structure. The temperature rise advantage of this pit organ was verified in comparison with an assumed substrate pit organ (as an artificial FPA structure). Inspired by the pit viper, we introduced this structure to infrared FPA, replacing the conventional substrate FPA. The substrate-free FPA was fabricated by micro-elctromechanical systems (MEMS) process and placed into an infrared imaging system to obtain thermal images of the human body in atmosphere and vacuum working conditions. We show that the infrared capability of the substrate-free pit organ was achieved.
Collapse
|
8
|
Kohl T, Bothe MS, Luksch H, Straka H, Westhoff G. Organotopic organization of the primary Infrared Sensitive Nucleus (LTTD) in the western diamondback rattlesnake (Crotalus atrox). J Comp Neurol 2014; 522:3943-59. [PMID: 24989331 DOI: 10.1002/cne.23644] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/25/2014] [Accepted: 06/30/2014] [Indexed: 11/08/2022]
Abstract
Pit vipers (Crotalinae) have a specific sensory system that detects infrared radiation with bilateral pit organs in the upper jaw. Each pit organ consists of a thin membrane, innervated by three trigeminal nerve branches that project to a specific nucleus in the dorsal hindbrain. The known topographic organization of infrared signals in the optic tectum prompted us to test the implementation of spatiotopically aligned sensory maps through hierarchical neuronal levels from the peripheral epithelium to the first central site in the hindbrain, the nucleus of the lateral descending trigeminal tract (LTTD). The spatial organization of the anatomical connections was revealed in a novel in vitro whole-brain preparation of the western diamondback rattlesnake (Crotalus atrox) that allowed specific application of multiple neuronal tracers to identified pit-organ-supplying trigeminal nerve branches. After adequate survival times, the entire peripheral and central projections of fibers within the pit membrane and the LTTD became visible. This approach revealed a morphological partition of the pit membrane into three well-defined sensory areas with largely separated innervations by the three main branches. The peripheral segregation of infrared afferents in the sensory epithelium was matched by a differential termination of the afferents within different areas of the LTTD, with little overlap. This result demonstrates a topographic organizational principle of the snake infrared system that is implemented by maintaining spatially aligned representations of environmental infrared cues on the sensory epithelium through specific neuronal projections at the level of the first central processing stage, comparable to the visual system.
Collapse
Affiliation(s)
- Tobias Kohl
- Chair of Zoology, Technische Universität München, Freising-Weihenstephan, Germany
| | | | | | | | | |
Collapse
|