Comparative Morphology of Central Neuropils in the Brain of Arthropods and Its Evolutionary and Functional Implications


Most insects and decapod crustaceans possess an assemblage of midline neuropils, the central complex. Recent phylogenetic studies show a sister-group relationship between hexapods and decapods, suggesting that central complexes in both groups are homologous structures derived from a basal ancestral neuropil [22]. This ancestral archetype of the central complex (lacking the protocerebral bridge) might be represented in the chilopods. Until recently, diplopods were regarded as closely related to chilopods and united within the taxon Myriapoda. The entire lack of a midline neuropil in diplopods, however, renders the monophyletic origin of the class Myriapoda unlikely [15]. In this study we used a palette of immunocytochemical and neuroanatomical methods to investigate mid-line neuropils in hitherto poorly examined arthropod groups. Of special interest for resolving arthropod phylogeny are onychophorans, who are believed to be an evolutionary ancient group that resembles the ancestors of modern arthropods. Striking similarities in central brain neuroarchitecture of the onychophoran Euperipatoides rowellii and of a chelicerate species, however, suggest a close phylogenetic relationship between these two groups. Our findings imply that onychophorans either represent the oldest form of the chelicerates or that extant onychophorans have developed from chelicerate-like ancestors by neoteny.


  1. 1.

    Bausenwein, B., M ller, N. R., Heisenberg, M. (1994) Behavior-dependent activity labeling in the central complex of Drosophila during controlled visual stimulation. J. Comp. Neurol. 340, 255–268.

    CAS  Article  Google Scholar 

  2. 2.

    Bodian, D. (1936) Anew method for staining nerve fibers and nerve endings in mounted paraffin sections. Anat. Rec. 65, 89–97.

    Article  Google Scholar 

  3. 3.

    Bordeaux, H. B. (1979) Arthropod Phylogeny with Special Reference to Insects. Wiley, New York.

    Google Scholar 

  4. 4.

    Brusca, R. C., Brusca, G. J. (1990) Invertebrates. Sinauer, Sunderland.

    Google Scholar 

  5. 5.

    Damen, W. G. M. (2002) Parasegmental organization of the spider embryo implies that the parasegment is an evolutionary conserved entity in arthropod embryogenesis. Development 129, 1239–1250.

    CAS  PubMed  Google Scholar 

  6. 6.

    Dearden, P. K., Donly, C., Grbic, M. (2002) Expression of pair-rule gene homologues in a chelicerate: early patterning of the two-spotted spider mite Tetranychus urticae. Development 129, 5461–5472.

    CAS  Article  Google Scholar 

  7. 7.

    Farley, R. D. (2001) Development of segments and appendages in embryos of the desert scorpion Paruroctomus mesaensis (Scorpiones: Vaejovidae). J. Morphol. 250, 70–88.

    CAS  Article  Google Scholar 

  8. 8.

    Fl gel, J. H. L. (1878) ber den einheitlichen Bau des Gehirns in den verschiedenen Insektenordnungen. Z. Wiss. Zool. 30 (supplement), 556–592.

    Google Scholar 

  9. 9.

    Grenier, J. K., Garber, T. L., Warren, R., Whitington, P. M., Carroll, S. (1997) Evolution of the entire arthropod Hox gene set predated the origin and radiation of the onychophoran/arthropod clade. Curr. Biol. 7, 547–553.

    CAS  Article  Google Scholar 

  10. 10.

    Hanesch, U., Fischbach, K. F., Heisenberg, M. (1989) Neuronal architecture of the central complex in Drosophila melanogaster. Cell Tissue Res. 257, 343–366.

    Article  Google Scholar 

  11. 11.

    Holmgren, N. (1916) Zur vergleichenden Anatomie des Gehirns von Polychaeten, Onychophoren, Xiphosuren, Arachniden, Crustaceen, Myriapoden und Insekten. K. Svenska Vetensk. Akad. Handl. 56, 1–303.

    Google Scholar 

  12. 12.

    Homberg, U. (1985) Interneurons in the central complex in the bee brain (Apis mellifera, L.). J. Insect Physiol. 31, 251–264.

    Article  Google Scholar 

  13. 13.

    Homberg, U. (1991) Neuroarchitecture of the central complex in the brain of the locust Schistocerca gregaria and S. americana as revealed by serotonin immunocytochemistry. J. Comp. Neurol. 303, 245–254.

    CAS  Article  Google Scholar 

  14. 14.

    Ioffe, I. D. (1963) Structure of the brain of Dermacentor pictus Herm. (Chelicerata, Acarina). Zool. Zh. 42, 1472–1484.

    Google Scholar 

  15. 15.

    Loesel, R., N ssel, D. R., Strausfeld, N. J. (2002) Common design in a unique midline neuropil in the brains of arthropods. Arthropod Structure & Development 31, 77–91.

    Article  Google Scholar 

  16. 16.

    Milde, J. J. (1988) Visual responses of interneurons in the posterior median protocerebrum and the central complex of the honeybee Apis mellifera. J. Insect Physiol. 34, 427–436.

    Article  Google Scholar 

  17. 17.

    Popadic, A., Panganiban, G., Rusch, D., Shear, W. A., Kaufman, T. C. (1998) Molecular evidence for the gnathobasic derivation of arthropod mandibles and for the appendicular origin of the labrum and other structures. Dev. Genes. Evol. 208, 142–150.

    CAS  Article  Google Scholar 

  18. 18.

    Renn, S. C., Armstrong, J. D., Yang, M., Wang, Z., An, K., Kaiser, K., Taghert, P. H. (1999) Genetic analysis of the Drosophila ellipsoid body neuropil: Organization and development of the central complex. J. Neurobiol. 41, 189–207.

    CAS  Article  Google Scholar 

  19. 19.

    Sandeman, D., Scholz, G. (1995) Ground plans, evolutionary changes and homologies in decapod crustacean brains. In: Breidbach, O., Kutsch, W. (eds) The Nervous System of Invertebrates: An Evolutionary and Comparative Approach. Birkh user, Basel, pp. 329–347.

    Google Scholar 

  20. 20.

    Stay, B., Chan, K. K., Woodhead, A. P. (1992) Allatostatin-immunoreactive neurons projecting to the corpora allata of adult Diploptera punctata. Cell Tissue Res. 270, 15–23.

    CAS  Article  Google Scholar 

  21. 21.

    Strausfeld, N. J. (1976) Atlas of an insect brain. Springer, Heidelberg.

    Book  Google Scholar 

  22. 22.

    Strausfeld, N. J. (1998) Crustacean-insect relationships: the use of brain characters to derive phylogeny amongst segmented invertebrates. Brain Behav. Evol. 52, 186–206.

    CAS  Article  Google Scholar 

  23. 23.

    Strausfeld, N. J. (1999) A brain region in insects that supervises walking. Progr. Brain Res. 123, 273 284.

    Google Scholar 

  24. 24.

    Strausfeld, N. J., Barth, F. G. (1993) Two visual systems in one brain: Neuropils serving the secondary eyes of the spider Cupiennius salei. J. Comp. Neurol. 328, 43–62.

    CAS  Article  Google Scholar 

  25. 25.

    Strausfeld, N. J., Weltzien, P., Barth, F. G. (1993) Two visual systems in one brain: Neuropils serving the principal eyes of the spider Cupiennius salei. J. Comp. Neurol. 328, 63–75.

    CAS  Article  Google Scholar 

  26. 26.

    Strauss, R., Heisenberg, M. (1990) Coordination of legs during straight walking and turning in Drosophila melanogaster. J. Comp. Physiol. A 167, 403–412.

    CAS  Article  Google Scholar 

  27. 27.

    Strauss, R., Trinath, T. (1996) Is walking in a straight line controlled by the central complex? Evidence from a new Drosophila mutant. In: Elsner, N., Schnitzler, U. (eds), Proceedings of the 24th G ttingen Neurobiology Conference. Vol II. Thieme, Stuttgart, p. 135.

  28. 28.

    Strauss, R., Hanesch, U., Kinkelin, M., Wolf, R., Heisenberg, M. (1992) No-bridge of Drosophila melanogaster portrait of a structural mutant of the central complex. J. Neurogen. 8, 125–155.

    CAS  Article  Google Scholar 

  29. 29.

    Utting, M., Agricola, H. J., Sandeman, R., Sandeman, D. (2000) Central complex in the brain of crayfish and its possible homology with that of insects. J. Comp. Neurol. 416, 245–261.

    CAS  Article  Google Scholar 

  30. 30.

    Vitzthum, H., Mueller, M., Homberg, U. (2002) Neurons of the central complex of the locust Schistocerca gregaria are sensitive to polarized light. J. Neurosci. 22, 1114–1125.

    CAS  Article  Google Scholar 

  31. 31.

    Wedeen, C. J., Kostriken, R. G., Leach, D., Whitington, P. (1997) Segmentally iterated expression of an engrailed-class gene in the embryo of an Australian onychophoran. Dev. Genes Evol. 270, 282–286.

    Article  Google Scholar 

  32. 32.

    Weltzien, P., Barth, F. G. (1991) Volumetric measurements do not demonstrate that the spider brain central body has a special role in web building. J. Morphol. 207, 1–8.

    Article  Google Scholar 

  33. 33.

    Williams, J. L. D. (1975) Anatomical studies of the insect central nervous system: A ground-plan of the midbrain and an introduction to the central complex in the locust Schistocerca gregaria (Orthoptera). J. Zool. 176, 67–86.

    Google Scholar 

  34. 34.

    Winther, Å. M. E., N ssel, D. R. (2001) Intestinal peptides as circulating hormones: release of tachykinin-related peptide from the midgut of locust and cockroach. J. Exp. Biol. 204, 1269–1280.

    CAS  PubMed  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to R. Loesel.

Additional information

Presented at the 10th ISIN Symposium on Invertebrate Neurobiology, July 5–9, 2003, Tihany, Hungary.

Rights and permissions

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Reprints and Permissions

About this article

Cite this article

Loesel, R. Comparative Morphology of Central Neuropils in the Brain of Arthropods and Its Evolutionary and Functional Implications. BIOLOGIA FUTURA 55, 39–51 (2004).

Download citation


  • Central complex
  • immunocytochemistry
  • neuroanatomy
  • Onychophora
  • locomotor control