@article {5, title = {Functional structure of antennal sensilla in the myrmecophilous beetle Paussus favieri (Coleoptera, Carabidae, Paussini).}, journal = {Micron}, volume = {43}, year = {2012}, month = {2012 Jun}, pages = {705-19}, abstract = {

The evolution of a myrmecophilous lifestyle in beetles is often associated with morphological alterations. In particular, the antennae of all members of the myrmecophilous ground beetle tribe Paussini are greatly modified, with flagellomeres flattened or crassate, frequently reduced in number from 9 to 5 or even 1 single "antennal club". The enhanced glandular function of the antennal club has been recently described by scanning (SEM) and transmission (TEM) electron microscopy in Paussus favieri Fairmaire, 1851, where the antenna has become a complex glandular organ, supplying rewarding substances to the ants. In the present work, the antennal sensilla of P. favieri are investigated by SEM, TEM and focused ion beam (FIB/SEM) technology. Most sensilla of scape and antennal club are highly modified mechanoreceptors (i.e. multipointed, fringed, branched, brush-like, sickle-shaped), singly or grouped in tufts ("antennal symphilous organs"). These "trichomes", here assigned to 8 different morphotypes of sensilla chaetica (Ch.1-Ch.8), show a variable number of basal pores (present also at the base of the taste sensilla Ch.9), which spread dense substances of unknown chemical composition on the seta. Although hygro-, thermo- and chemoreceptors are reduced in number as compared with non-myrmecophilous relatives, and mainly relegated to the apex of the antennal club, their diversity is comparable to that of other carabid beetles: two types of sensilla trichodea (Tr.1-Tr.2); three types of basiconica (Ba.1-Ba.3); one type of campaniformia (Ca); one type of coeloconica (Co) and one type of B{\"o}hm sensilla (Bo). Contrary to the hypothesis that Paussus species lack a Johston{\textquoteright}s organ, a non-connective chordotonal organ composed of 9 groups of scolopidia has been found inside the pedicel. A comparison between sensilla of P. favieri and those of other non-myrmecophilous and myrmecophilous ground beetle species is provided.

}, keywords = {Animals, Arthropod Antennae, Beetles, Female, Male, Sensilla}, issn = {1878-4291}, doi = {10.1016/j.micron.2011.10.013}, author = {Di Giulio, Andrea and Maurizi, Emanuela and Stacconi, Marco Valerio Rossi and Romani, Roberto} } @article {6, title = {Fine structure of the antennal glands of the ant nest beetle Paussus favieri (Coleoptera, Carabidae, Paussini).}, journal = {Arthropod Struct Dev}, volume = {38}, year = {2009}, month = {2009 Jul}, pages = {293-302}, abstract = {

The antennae of the ant nest beetle Paussus favieri are studied by using both SEM and TEM. In the myrmecophilous genus Paussus, these structures are composed of three joints: scape, pedicel and a wide third joint, the "antennal club", resulting from the fusion of antennomeres A3-A11 (flagellum). The antennal club shows an exceptional glandular activity, with the presence of pores mostly crowded in special hairless cuticular areas, surrounding the base of single setae, grouped at the base of tufts of setae, or positioned inside deep pockets that store the secretions, with filiform material arising from them. The surface of A1 and A3 are covered by mechanoreceptors, modified to spread the glandular exudates, while the chemoreceptors are restricted to the apex of the club. The fine structural analysis shows a great number of antennal glands, that can be referred to three main typologies: type A (GhA) bi-cellular, composed of a large secretory cell and a small duct cell, positioned close to the antennal surface; type B (GhB), tri-cellular, composed of two secretory cells and one duct cell, less frequent and positioned deep inside the antennal club; type C (GhC), rare, located deeply within the antennal lumen, in the vicinity of the trophocytes. This complexity indicates that more than one substance could be released from the antennae. Possible functional aspects of the secretions dealing with symbiotic interaction with the host ants are discussed.

}, keywords = {Animals, Ants, Beetles, Endocrine Glands, Female, Male, Mechanoreceptors, Microscopy, Electron, Scanning, Morocco, Symbiosis}, issn = {1873-5495}, doi = {10.1016/j.asd.2009.01.001}, author = {Di Giulio, Andrea and Rossi Stacconi, Marco Valerio and Romani, Roberto} } @article {2, title = {A review of myrmecophily in ant nest beetles (Coleoptera: Carabidae: Paussinae): linking early observations with recent findings.}, journal = {Naturwissenschaften}, volume = {94}, year = {2007}, month = {2007 Nov}, pages = {871-94}, abstract = {

Myrmecophily provides various examples of how social structures can be overcome to exploit vast and well-protected resources. Ant nest beetles (Paussinae) are particularly well suited for ecological and evolutionary considerations in the context of association with ants because life habits within the subfamily range from free-living and predatory in basal taxa to obligatory myrmecophily in derived Paussini. Adult Paussini are accepted in the ant society, although parasitising the colony by preying on ant brood. Host species mainly belong to the ant families Myrmicinae and Formicinae, but at least several paussine genera are not host-specific. Morphological adaptations, such as special glands and associated tufts of hair (trichomes), characterise Paussini as typical myrmecophiles and lead to two different strategical types of body shape: while certain Paussini rely on the protective type with less exposed extremities, other genera access ant colonies using glandular secretions and trichomes (symphile type). We compare these adaptations with other taxonomic groups of insects by joining contemporary research and early sources and discuss the possibility of an attracting or appeasing effect of the secretion. Species that are ignored by their host ants might use chemical mimicry instead. Furthermore, vibrational signals may contribute to ant-beetle communication, and chemical signals have proven to play a role in host finding. The powerful defense chemistry of paussines as "bombardier beetles" is not used in contact with host ants. We attempt to trace the evolution of myrmecophily in paussines by reviewing important aspects of the association between paussine beetles and ants, i.e. morphological and potential chemical adaptations, life cycle, host specificity, alimentation, parasitism and sound production.

}, keywords = {Animals, Arthropods, Beetles, Motor Activity, Nesting Behavior, Phylogeny, Social Behavior}, issn = {0028-1042}, doi = {10.1007/s00114-007-0271-x}, author = {Geiselhardt, Stefanie F and Peschke, Klaus and Nagel, Peter} }