Andrea Di Giulio

Behavior of Paussus favieri (Coleoptera, Carabidae, Paussini): A Myrmecophilous Beetle Associated with Pheidole pallidula (Hymenoptera, Formicidae)

Several specimens of the myrmecophilous beetle Paussus favieri were reared in ant nests of Pheidole pallidula. Their interactions were recorded and all behaviors observed are described. Duration and frequency of five behaviors of P. favieri were analyzed with ANOVA and post hoc Tukey tests; these comprised rewarding, antennal shaking, antennation, escape, and “no contact”. Significant differences both in duration and in frequency among behaviors were detected. The main result is that the rewarding behavior, during which the beetle provides attractive substances to the host, is performed significantly more frequently than all others. This result strongly supports the hypothesis that the chemicals provided by the beetles and licked by the ants are of great importance for the acceptance and the full integration of P. favieri in the ant society. This result also suggests that, contrary to previous findings and interpretations, the myrmecophilous strategy of P. favieri is very similar to the symphilous strategy described for P. turcicus. The occasional interactions of some beetle specimens with the P. pallidula queen were recorded, illustrated, and discussed, indicating the possibility of a more complex strategy of P. favieri involving a chemical mimicry with the queen. In addition, the courtship performed by the beetle is described for the first time, together with a peculiar “cleaning” behavior, which we hypothesize functions to spread antennal chemicals over the body surfaces.

Systematics and biogeography of the genus Actenodia (Coleoptera: Meloidae: Mylabrini)

Abstract The genus Actenodia Laporte de Castelnau (Meloidae: Mylabrini) is revised. It includes 18 species distributed in the Mediterranean and Saharo‐Arabian regions, and in eastern and southern Africa; A. carpanetoi sp.n. from Mozambique is described. The bionomics of the genus is summarized, according to a collection of records on phenology, elevation, habitat preference and host plants. A classification of the genus is proposed after a morphological cladistic analysis: one Afrotropical lineage clearly emerged with three distinct groups of species, whereas other taxa, all Palaearctic except A. mirabilis, remained unresolved. The analysis of the nuclear internal transcribed spacer 2 rDNA sequences of some Palaearctic and Afrotropical species supports the distinction of the Afrotropical lineage. The first instar larvae of two species, A. chrysomelina from southern Africa and A. denticulata from Arabia, are described for the first time and compared with two other Palaearctic species described previously; inferences from larval morphology are discussed. The adult morphology of all species is described briefly and illustrated, and a key to the species is provided, as well as locality data. Three new synonymies are proposed: A. extera Dvořák, 1993syn.n. =A. septempunctata Baudi di Selve, 1878; A. sexpunctata Pic, 1948syn.n. =A. curtula Fähraeus, 1870 ; A. unimaculata lanzai Kaszab, 1973syn.n. =A. unimaculata Pic, 1908. The biogeography of the genus is discussed within the framework of a more general analysis of the disjunct distribution models.

Review of the southern African genus Prolytta Kaszab, with a description of the first-instar larva, and bionomic and taxonomic remarks (Coleoptera : Meloidae)

The taxonomy and bionomics of the southern African meloid genus Prolytta are reviewed. First-instar larvae of four species (P. coriacea, P. pallidipennis, P. lucida and P. semilineata) are described and keyed. The morphology of the specialised setae found in the larvae of this genus is discussed and compared with that of other blister beetles. Based on adult and larval morphology, two assemblages of species, the pallidipennis-group and the lucida-group, are recognised. Included are a key and catalogue of species, taxonomic remarks and several new faunistic records. Two new synonymies, Prolytta lucidicollis Kaszab, 1967 = Prolytta coriacea Kaszab, 1967 and Prolytta sumptuosa (Laporte de Castelnau, 1840) = Prolytta nitidula (Fabricius, 1775), are proposed.

Larval morphology of the Meloe subgenus Mesomeloe: Inferences on its phylogenetic position and a first instar larval key to the Meloe subgenera (Coleoptera, Meloidae)

Abstract The triungulin of Meloe (Mesomeloe) coelatus, is described; the first instar larva of this subgenus was previously unknown. In cluded is a comparative analysis of morphological characters of Mesomeloe, phylogenetic inferences on the position of this Palaearctic desertic taxon, and a key to the first instar larvae of Meloe subgenera.

Taxonomic remarks on Bela atlantidea (Mollusca: Gastropoda: Mangeliidae) and updated distribution in the Mediterranean basin

Brachycythara atlantidea (Knudsen, 1952) and B. beatriceae Mariottini, 2007, both species belonging to the family Mangeliidae, are here moved to the genus Bela Gray, 1847, based on morphological shell features. The new epithets are: Bela atlantidea (Knudsen, 1952) comb. nov. and Bela beatriceae (Mariottini, 2007) comb. nov. The recently described Bela clarae Peňas & Rolan, 2008 is here considered a junior synonym of B. atlantidea according to a comparative scanning electron microscopy analysis of the shells. The distribution of B. atlantidea in the Mediterranean basin is therefore reconsidered including all known records of B. clarae .

Sexual and Cleaning Behavior and Related Morphology in the Genus Cerocoma (Coleoptera: Meloidae)

The study of sexual behavior has been largely utilized in phylogenetic analyses of Meloidae beetles. Sexual behavior of the tribe Cerocomini is almost unknown, even though the genus Cerocoma shows the most striking sexual dimorphism in the family. In this paper, the sexual behavior of five species, C. (Cerocoma) adamovichiana, C. (C.) graeca, C. (C.) schaefferi, C. (Metacerocoma) schreberi, and C. (M.) prevezaensis, is described. The cleaning behavior of this genus, previously unknown, is also discussed. A morphological analysis by scanning electron microscopy of sexually dimorphic anatomical features of antennae, maxillary palpi, and forelegs, involved in cleaning and sexual activities, is carried out.

Functional anatomy of the explosive defensive system of bombardier beetles (Coleoptera, Carabidae, Brachininae)

This paper provides the first comparative anatomical study of the explosive pygidial defensive system of bombardier beetles in species classified in three brachinine subtribes: Brachinus (Brachinina), Pheropsophus (Pheropsophina) and Aptinus (Aptinina). We investigated the morphology and ultrastructure of this system using optical, fluorescence, and focused ion beam (FIB/SEM) microscopy. In doing so, we characterized and comparatively discussed: (1) the ultrastructure of the gland tissues producing hydroquinones and hydrogen peroxide (secretory lobes), and those producing catalases and peroxidases (accessory glands); (2) the complex anatomy of the collecting duct; (3) the arrangement of the muscular bundles and the folding of the cuticle of the reservoir, suggesting a functional division of this chamber (dynamic part and storage part); (4) the great structural diversity of sculpticles inside the reaction chamber, where we could recognize six main types of microsculpture located in specific districts of the chamber. Additionally, using fluorescence microscopy, we highlighted the presence of resilin in two structures strongly subjected to mechanical stress during the discharge, the valve and the turrets of the reaction chamber. The results of this paper give a solid anatomic overview of the most popular beetle defensive system, contributing to the debate on its evolution within the Carabidae.

Environmental tuning of an insect ensemble: the tenebrionid beetles inhabiting a Mediterranean coastal dune zonation.

Few studies have investigated insect ensembles, i.e. phylogenetically bounded groups of species that use a similar set of resources within a community. The zonation of dune vegetation makes these ecosystems ideal for the study of insect ensembles in a short space. In this study, we investigated if the tenebrionid beetles forming an ensemble on a dune zonation showed variations in community organization (relative abundances and species diversity) in different but spatially associated biotopes defined by different plant communities. Three biotopes (corresponding to European Commission habitat 2110, 2120 and 2230) of a well-preserved Mediterranean dune were sampled using square plots of 2×2 m at three places. To investigate if there was some association between species and habitat we applied a χ(2) test. Variations in community structure parameters were investigated using Shannon index. The three biotopes host tenebrionid communities with similar species composition and overall abundances, confirming that they form a single ensemble. However, tenebrionid species are differently associated with different biotopes along the zonation, with some species occurring with different proportions among the biotopes. A local selection process can be postulated as a mechanism responsible for these differences.

The larva of Eustra (Coleoptera, Paussinae, Ozaenini): a facultative associate of ants

Abstract Larvae of the ground beetle genus Eustra Schmidt-Goebel are described and illustrated for the first time and some biological notes are reported. One specimen of an unknown Eustra species was collected while excavating a nest of the ant Pachycondyla javana Mayr, in Taiwan, which is the first report of a paussine associated with a member of the ant subfamily Ponerinae. Several larvae and adults of a second species, Eustra chinensis Bänninger, were collected in Shanghai under bark with no association with ants. First instar larvae of the latter species were also reared in the lab. The occurrence of larvae of the genus Eustra both inside and outside ant nests, together with a report of adults collected inside a nest in Taiwan, suggests that members of this genus may be facultative predators or facultative symbionts of ants, an attribute that has never been reported for this genus. The larvae of Eustra show several unique features, including a peculiar bidentate mandibular apex, an extremely long galea, one of two tarsal claws greatly reduced, abdominal setae (including those of terminal disk) elongate and clavate at apex, urogomphi wide and flattened, and inflated sensilla S-I. Larvae were studied by both optical and scanning electron microscopy, their morphological features are compared with those of other described Paussinae larvae, and their potential phylogenetic and functional significance are discussed.

The Pied Piper: A Parasitic Beetle's Melodies Modulate Ant Behaviours.

Ants use various communication channels to regulate their social organisation. The main channel that drives almost all the ants’ activities and behaviours is the chemical one, but it is long acknowledged that the acoustic channel also plays an important role. However, very little is known regarding exploitation of the acoustical channel by myrmecophile parasites to infiltrate the ant society. Among social parasites, the ant nest beetles (Paussus) are obligate myrmecophiles able to move throughout the colony at will and prey on the ants, surprisingly never eliciting aggression from the colonies. It has been recently postulated that stridulatory organs in Paussus might be evolved as an acoustic mechanism to interact with ants. Here, we survey the role of acoustic signals employed in the Paussus beetle-Pheidole ant system. Ants parasitised by Paussus beetles produce caste-specific stridulations. We found that Paussus can “speak” three different “languages”, each similar to sounds produced by different ant castes (workers, soldiers, queen). Playback experiments were used to test how host ants respond to the sounds emitted by Paussus. Our data suggest that, by mimicking the stridulations of the queen, Paussus is able to dupe the workers of its host and to be treated as royalty. This is the first report of acoustic mimicry in a beetle parasite of ants.