The arthropod mushroom body: Its functional roles, evolutionary enigmas and mistaken identities

Abstract

Insects share the same physical environment as terrestrial vertebrates. However, insects are vastly more successful in terms of their adaptive radiation and colonization. The biomass of insects alone is said to outweigh all other organisms and it can be speculated that their evolutionary success is a consequence, not only of their environmental colonization, but also of their behavioral versatility which sets them apart from other terrestrial arthopods. If this hypothesis is correct, it might be expected that there exist neural organizations that are peculiar to, or greatly elaborated in, the Insecta alone. This chapter describes the occurrence among selected arthropods of a brain region that, in eusocial insects, reaches great complexity and is implicated in learning and memory. Its identification in various taxa is assessed against the background of current theories of arthropod evolution and brain segmentation.

Behavioral development in the honey bee: toward the study of learning under natural conditions.

“…This is consistent with the suggestive (but by no means definitive) findings of Vowles (1964) and Bernstein and Bernstein (1969) for the wood ant Formica rufa Possible functional roles of the mushroom bodies in arthropods have been reviewed recently by Erber et al (1987) and Strausfeld et al (1995).…”

“…Implicit acceptance of this hypothesis actually lies at the root of the long-standing fascination with the mushroom bodies of insects. Biologists beginning with Dujardin in 1850 noted that bees, and other social insects thought to be the most behaviorally complex and socially advanced, had larger mushroom bodies, especially the calyces (Howse 1975;Strausfeld et al 1995).…”

Phylogenetisches Symposium Göttingen

“…5A, D; Strausfeld 1976). The brain therefore provides a wealth of morphological features that can be analysed on a different level than the architecture of single individually identifiable neurons as described above, and the information obtained from analysing brain design is an important supplement for the phylogenetic data obtained from the ventral nerve cord (reviews Strausfeld et al 1995, Strausfeld 1998, Harzsch 2004a, Fanenbruck and Harzsch 2005, Harzsch 2006. Recent examples for neuroanatomical studies with a phylogenetic motivation have focused on the brain layout in Onychophora (Eriksson and Budd 2000, Eriksson et al 2003, Strausfeld et al 2006a, Tardigrada (Dewel and Dewel 1996, Dewel et al 1999), Chelicerata (Breidbach and Wegerhoff 1993, Mittmann and Scholtz 2003, Harzsch et al 2005b, and remipede crustaceans ( Fig.…”

“…"Die molekularen Methoden haben sich durchgesetzt, weil sie innerhalb weniger Jahre überzeugend bewiesen haben, dass sie bei der Rekonstruktion phylogenetischer Verwandtschaften den klassischen morphologischen Merkmalen überlegen sind" (Bachmann 1999: 20 Paul (1989Paul ( ,1990, a neurobiologist from the University of Victoria/Canada who brought together the topics "nervous system" and "phylogeny" to coin the term "neural phylogeny" which was analysed by a "neurophylogenist". Structure and development of the nervous system more than before contribute important arguments to the revived debate on arthropod relationships (reviews e. g. Arbas et al 1991, Breidbach 1995, Kutsch and Breidbach 1995, Strausfeld et al 1995, Whitington 1996, Nilsson and Osorio 1997, Whitington and Bacon 1997, Strausfeld 1998, Strausfeld and Hildebrand 1999, Paulus 2000, Dohle 2001, Harzsch 2001a, Richter 2002a, Harzsch 2003a − The number and course of the neurites with respect to the ganglionic framework.− The size of the neuronal somata.− The target organs that certain neurons innervate.− Physiological criteria: such as the characterization of a neuron as inhibitory or excitatory, or as spiking versus − Developmental criteria: the common ontogenetic origin of neurons from precursor cells through equivalent developmental programmes of gene expression and cell to cell interactions. A general aspect of nerve cells is the expression of certain neurotransmitters, receptors, and other specific molecular and biochemical markers.…”

“…To my knowledge it was Dorothy Paul (1989Paul ( ,1990, a neurobiologist from the University of Victoria/Canada who brought together the topics "nervous system" and "phylogeny" to coin the term "neural phylogeny" which was analysed by a "neurophylogenist". Structure and development of the nervous system more than before contribute important arguments to the revived debate on arthropod relationships (reviews e. g. Arbas et al 1991, Breidbach 1995, Kutsch and Breidbach 1995, Strausfeld et al 1995, Whitington 1996, Nilsson and Osorio 1997, Whitington and Bacon 1997, Strausfeld 1998, Strausfeld and Hildebrand 1999, Paulus 2000, Dohle 2001, Harzsch 2001a, Richter 2002a, Harzsch 2003a) so that arthropod "neurophylogeny" is now a well-established and active discipline (e.g. : Harzsch 2002a, 2003b, Fahrbach 2004, Loesel 2005, Harzsch et al 2005a, Strausfeld 2005, Harzsch 2006).…”