scholarly journals The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes

2020 ◽  
Author(s):  
Sara Arganda ◽  
Andrew P. Hoadley ◽  
Evan S. Razdan ◽  
Isabella B. Muratore ◽  
James F. A. Traniello
Keyword(s):  
Division Of Labor ◽  
Compound Eye ◽  
Optic Lobe ◽  
Light Availability ◽  
Visual Sensitivity ◽  
Atta Cephalotes ◽  
Brain Organization ◽  
Functional Neuroplasticity ◽  
Parameter Values ◽  
Peripheral Sensory

AbstractOur understanding of how the design of peripheral sensory structures is coupled with neural processing capacity to adaptively support division of labor is limited. Workers of the remarkably polymorphic fungus-growing ant Atta cephalotes are behaviorally specialized by size: the smallest workers (minims) tend fungi in dark subterranean chambers while larger workers perform tasks mainly outside the nest. These strong differences in worksite light conditions are predicted to influence sensory and processing requirements for vision. We found that eye structure and visual neuropils have been be selected to maximize task performance according to light availability. Minim eyes had few ommatidia, large interommatidial angles and eye parameter values, suggesting selection for visual sensitivity over acuity. Large workers had larger eyes with disproportionally more and larger ommatidia, and smaller interommatidial angles and eye parameter values, reflecting peripheral sensory adaptation to ambient rainforest light. Additionally, optic lobe and mushroom body collar volumes were disproportionately small in minims, and within the optic lobe, lamina and lobula relative volumes increased with worker size whereas the medulla decreased. Visual system phenotypes thus correspond to task specializations in dark or light environments and reflect a functional neuroplasticity underpinning division of labor in this socially complex agricultural ant.

scholarly journals The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes

2020 ◽  
Vol 206 (4) ◽  
pp. 651-662 ◽  
Author(s):  
Sara Arganda ◽  
Andrew P. Hoadley ◽  
Evan S. Razdan ◽  
Isabella B. Muratore ◽  
James F. A. Traniello
Keyword(s):  
Division Of Labor ◽  
Compound Eye ◽  
Atta Cephalotes ◽  
Brain Organization

scholarly journals Peripheral sensory organs vary among ant workers but variation does not predict division of labor

2019 ◽  
Vol 158 ◽  
pp. 137-143 ◽  
Author(s):  
Nicole Leitner ◽  
Daniel Charbonneau ◽  
Wulfila Gronenberg ◽  
Anna Dornhaus
Keyword(s):  
Division Of Labor ◽  
Sensory Organs ◽  
Peripheral Sensory

scholarly journals Characterization of a reduced-eye mutant of the grasshopper, Melanoplus sanguinipes

Development ◽  
1984 ◽  
Vol 83 (1) ◽  
pp. 189-211
Author(s):  
D. J. Emery ◽  
K. A. Bell ◽  
W. Chapco ◽  
J. D. Steeves
Keyword(s):  
Compound Eye ◽  
Optic Lobe ◽  
Compound Eyes ◽  
Movement Detector ◽  
Melanoplus Sanguinipes ◽  
Optic Chiasma ◽  
Morphological Alterations ◽  
Tactile Stimuli ◽  
Normal Manner ◽  
Contralateral Movement

A reduced-eye (re) mutant grasshopper of Melanoplus sanguinipes has been characterized by small flat compound eyes lacking facets, no lateral ocelli and only a remnant of the median ocellus. The re grasshoppers walk, jump, fly and feed in a normal manner, but do not respond to visual and auditory stimuli, suggesting they may be blind and deaf. Extracellular recordings from the ventral nerve cord of re mutants verified the lack of neural activity in response to visual and auditory inputs, yet the mutants detected mechanical and tactile stimuli. Electroretinograms implied that a visual deficit may be within the photoreceptors of the compound eye. Histological examination of the compound eyes and ocelli indicated that the cells of the mutant compound eye incompletely differentiate. The optic lamina underlying the retina is missing, as is the outer optic chiasma. The medulla and lobula of the mutant optic lobe are present, however, the neuropil of the medulla lacks the characteristic axonal projection patterns of wild-type grasshoppers. The re grasshopper also lacks all ocellar nerves. Ocellar nerves are normally formed from processes of second order ocellar neurons (SONs), suggesting that if the mutant SONs are present within the protocerebrum, their morphology is drastically altered. Comparison of embryos and juvenile nymphs supports the suggestion that the alterations in the re visual system are the result of abnormal differentiation during development. Even though there is clear evidence of morphological alterations in second and third order optic lobe interneurons, one higher order visual interneuron of the midbrain, the descending contralateral movement detector (DCMD), has the same morphology as the DCMD in a wildtype brain. In this instance, the complete deprivation of the primary sensory input does not appear to alter cellular development.

scholarly journals The Spectral Sensitivity of Crayfish and Lobster Vision

1961 ◽  
Vol 44 (6) ◽  
pp. 1089-1102 ◽  
Author(s):  
Donald Kennedy ◽  
Merle S. Bruno
Keyword(s):  
Fresh Water ◽  
Spectral Sensitivity ◽  
Light Adaptation ◽  
Compound Eye ◽  
Monochromatic Light ◽  
Sensitivity Function ◽  
Visual Sensitivity ◽  
Long Wavelength ◽  
Cone Pigments ◽  
Sensitivity Data

(1) The spectral sensitivity function for the compound eye of the crayfish has been determined by recording the retinal action potentials elicited by monochromatic stimuli. Its peak lies at approximately 570 mµ. (2) Similar measurements made on lobster eyes yield functions with maxima in the region of 520 to 525 mµ, which agree well with the absorption spectrum of lobster rhodopsin if minor allowances are made for distortion by known screening pigments. (3) The crayfish sensitivity function, since it is unaffected by selective monochromatic light adaptation, must be determined by a single photosensitive pigment. The absorption maximum of this pigment may be inferred with reasonable accuracy from the sensitivity data. (4) The visual pigment of the crayfish thus has its maximum absorption displaced by 50 to 60 mµ towards the red end of the spectrum from that of the lobster and other marine crustacea. This shift parallels that found in both rod and cone pigments between fresh water and marine vertebrates. In the crayfish, however, an altered protein is responsible for the shift and not a new carotenoid chromophore as in the vertebrates. (5) The existence of this situation in a new group of animals (with photoreceptors which have been evolved independently from those of vertebrates) strengthens the view that there may be strong selection for long wavelength visual sensitivity in fresh water.

Postembryonic development of the visual system of Periplaneta americana

Development ◽  
1981 ◽  
Vol 66 (1) ◽  
pp. 235-255
Author(s):  
Robert J. Stark ◽  
Michael I. Mote
Keyword(s):  
Developmental Stage ◽  
Periplaneta Americana ◽  
Compound Eye ◽  
Optic Lobe ◽  
Postembryonic Development ◽  
Structural Differentiation ◽  
Eye Growth ◽  
Body Tissues ◽  
Optic Fibre ◽  
Cell Growth And Proliferation

The compound eyes of Periplaneta americana are connected by optic fibre tracts to an optic lobe composed of three sequential ganglia, the lamina, the medulla and the lobula respectively. The eyes and optic ganglia are organized into repeating sub-units arranged in a regular pattern. During postembryonic development, the number of subunits in the eye (ommatidia) increases from between 50 and 60 to over 2000, with a concomitant increase in the size of the optic lobe ganglia. The patterns of cell growth and proliferation were examined in serial section autoradiagraphs prepared following long and short exposures to [3H]thymidine during each developmental stage. Aspects of structural differentiation were examined in reduced silver-stained sections of nymphs at each developmental stage. Growth of the eye and optic ganglia resulted from the continuous proliferation of new cells throughout postembryonic development. Unlike other body tissues, growth of this system was independent of the moulting cycle. The pattern of growth observed in the optic ganglia directly reflected the growth of the eye. Growth of the compound eye occurs from a special zone of proliferation and differentiation located along all but its posterior margin. The lamina and medulla both grow by cell proliferation from a single neuroblast region located at the apex of the angle subtended by them. Cells which proliferate distally from this region differentiate into lamina neurons, while those that proliferate proximally differentiate into medulla neurons. Axons growing from these two adjacent regions meet at and add new new fibres to the distal end of the medulla neuropil. Specificity of the interneuronal connexions appears to result from a precise temporospatial sequencing of growth with the formation of the optic ganglia dependent on retinal development.

Formation of the retina—lamina projection of the cockroach: no evidence for neuronal specificity

Development ◽  
1981 ◽  
Vol 62 (1) ◽  
pp. 241-258
Author(s):  
Mark S. Nowel
Keyword(s):  
Compound Eye ◽  
Optic Lobe ◽  
Retinotopic Mapping ◽  
Neuronal Specificity ◽  
Position And Orientation ◽  
Topographical Mapping ◽  
Transplantation Experiments

There is a topographical mapping of neural elements onto the lamina neuropile of the optic lobe of the cockroach, such that adjacent ommatidia project to adjacent points (optic cartridges) in the lamina neuropile. Postembryonic growth of the compound eye occurs by addition of new ommatidia to its growing margin. Retinula axons grow from the newly formed ommatidia to the lamina. By transplantation experiments in which the position or the orientation of retinal material is altered, it is shown that retinula axons do not make connections in the lamina with respect to their old position and orientation, but rather, in keeping with their new situations, apparently maintaining a retinotopic mapping upon the optic lobe.

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