Anatomy of the stridulation apparatus of the beech leaf‐mining weevil and characterization of,and behavioral responses to,stridulation sounds

We investigated auditory signals and morphology of the stridulatory apparatus of the European beech leaf‐mining weevil, Orchestes fagi L. (Coleoptera: Curculionidae), an invasive herbivore now established in Nova Scotia, Canada, to determine their potential for enhancing survey tools to monitor the spread of the species in Canada. We recorded and described sounds produced by adult O. fagi, analyzed the morphology of the stridulatory mechanism for intersexual differences and asymmetry, and examined behavioral responses elicited in conspecifics by playback of stridulation recordings. Adult O. fagi produced sounds under three conditions: male in distress, female in distress, and male in the presence of female. Female distress chirps lasted significantly longer than male distress chirps and male chirps in the presence of females, but peak frequencies and mean number of chirps per s did not differ significantly among the three groups. Morphology of the stridulation structures in male and female O. fagi was compared using scanning electron microscopy. Orchestes fagi have an elytro‐tergal file‐ and scraper‐type sound production apparatus, through which sound is produced upon anterior motion of the abdomen. Female O. fagi have a ‘pars stridens’ that is longer and has more ridges than males. Width and number of ridges per length of pars stridens did not differ between the sexes. Evidence of asymmetry was found in male pars stridens, with the right side being longer than the left. Playback of recorded sounds to adult weevils suggests female O. fagi were repelled by sounds produced by distressed males.     

Stridulatory apparatus in the Italian species of the genus Laccobius erichson (Coleoptera : Hydrophilidae)

The stridulatory apparatus in males of the Italian species of the genus Laccobius Erichson (Coleoptera : Hydrophilidae) was examined by means of scanning electron microscope. In Laccobius, there is an elytron-uropleural type stridulatory apparatus. The “pars stridens” is situated on the 3rd abdominal pleurite and has an eulamellated structure. The “plectrum” is located on the inner elytron face. Significant subgeneric differences were found mainly in the extent of the areas, which make up the pars stridens and in the type of pleural denticulations. Differences in the plectrum cusps are also indicated.     

Susceptibility of sunflower inbred lines and putative resistance sources to Smicronyx fulvus LeConte (Coleoptera: Curculionidae)

The red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), is a primary seed-feeding pest of cultivated sunflowers, Helianthus annuus L., in North America. Host plant resistance is one tool available to complement insecticide-based management of S. fulvus. Artificial infestations of 30 adult weevils per head were used to determine whether variation for susceptibility to S. fulvus exists in previously released inbred lines, and how a new weevil-resistant line, HA 488, compares with other putative sources of resistance. Correcting for the number of seeds per head, 13 older inbred lines showed variation in per cent seed damage from 20% to 38%, with two lines (HA 412 HO, HA 821) being more damaged than most of the tested lines. Among four putative resistance sources, HA 488 was significantly less damaged (5%) than two previously identified open-pollinated varieties (PI 170424, PI 253417, with 13%–14% seed damage), while the source of the resistance in HA 488, PI 431542, was statistically intermediate (12%). The resistance available in HA 488 is a marked improvement, potentially reducing damage per weevil by two thirds or more, but additional work on genetic markers for resistance, economic thresholds and basic weevil biology (e.g. degree-day models for adult emergence) is needed to support implementation of integrated pest management for this key sunflower pest.     

Fourier and electrophysiological analyses of acoustic communication in Acheta domesticus

Waveform and spectral analysis were made on the call song of the cricket, Acheta domesticus. Sounds produced by unrestrained male crickets were led directly to a computer where discrete Fourier transforms were performed on selected segments of the call song. The findings revealed essentially pure tone carrier frequencies which result from the rate at which the individual teeth of the pars stridens are struck by the plectrum. An electrophysiologically determined audiogram showed good agreement with the dominant frequency of the call song, but was less sensitive and more broadly tuned than hearing curves of most fiels crickets.     

Two new species of the genus Rhynchitobius Sharp, 1889 (Coleoptera: Rhynchitidae) in Dominican amber

New species of rhynchitid weevils, Rhynchitobius tanyrhinus n. sp. and R. xuthocolus n. sp. (Coleoptera: Rhynchitidae) in the tribe Auletini are described from Dominican amber. The former species is characterized by a long rostrum, narrow pronotum and elytra, rugose elytral intervals and distinct elytral striae. The latter species has a short rostrum, wide antennal club, yellow legs, non-rugose elytral intervals and weak elytral striae. The present study describes the first representatives of the family Rhynchitidae from Dominican amber.     

Description of the stridulatory apparatus of the Far Eastern bark beetles <Emphasis Type="Italic">Polygraphus proximus</Emphasis> Blandford, 1894 and <Emphasis Type="Italic">P. jezoensis</Emphasis> Niisima, 1909 (Coleoptera,Curculionidae: Scolytinae)

The stridulatory organ structure in two Far Eastern bark beetles, Polygraphus proximus and P. jezoensis, is described. The elytro-tergal type of the stridulatory apparatus is found in P. jezoensis. The structure involved in acoustic communication of P. jezoensis is present only in males. The plectrum of P. proximus males is re-described. Similarly to that in P. jezoensis, it is formed by two tubercles at the distal margin of tergite VII. An additional type of stridulatory organ used for the producing of precopulatory courtship signals is described for males of P. proximus. In this type of stridulatory organ, transverse ridges on the costal margin of the elytron act as pars stridens, and the hind tibia, as the plectrum.     

Phylogenetic analysis of Geotrupidae (Coleoptera, Scarabaeoidea) based on larvae

Abstract. Thirty‐eight characters derived from the larvae of Geotrupidae (Scarabaeoidea, Coleoptera) were analysed using parsimony and Bayesian inference. Trees were rooted with two Trogidae species and one species of Pleocomidae as outgroups. The monophyly of Geotrupidae (including Bolboceratinae) is supported by four autapomorphies: abdominal segments 3–7 with two dorsal annulets, chaetoparia and acanthoparia of the epipharynx not prominent, glossa and hypopharynx fused and without sclerome, trochanter and femur without fossorial setae. Bolboceratinae showed notable differences with Pleocomidae, being more related to Geotrupinae than to other groups. Odonteus species (Bolboceratinae s.str.) appear to constitute the closest sister group to Geotrupinae. Polyphyly of Bolboceratinae is implied by the following apomorphic characters observed in the ‘Odonteus lineage’: anterior and posterior epitormae of epipharynx developed, tormae of epipharynx fused, oncyli of hypopharynx developed, tarsal claws reduced or absent, plectrum and pars stridens of legs well developed and apex of antennal segment 2 with a unique sensorium. A ‘Bolbelasmus lineage’ is supported by the autapomorphic presence of various sensoria on the apex of the antennal segment, and the subtriangular labrum (except Eucanthus). This group constituted by Bolbelasmus, Bolbocerosoma and Eucanthus is the first evidence for a close relationship among genera, but more characters should be analysed to test the support for the clade. A preliminary classification at tribe level of Geotrupinae is suggested as follows: Chromogeotrupini (type genus Chromogeotrupes), Lethrini (type genus Lethrus), Taurocerastini (type genus Taurocerastes) and Geotrupini (type genus Geotrupes). Some ecological facts of Geotrupidae evolution could also be explained by the present results, such as those related to diet and nesting behaviour. Both coprophagy and male–female co‐operation in nesting appear as derived traits.     

Immunohistochemical and radioautographic evidence of monoamine-containing cells in bioluminescent elytra of the scale-worm Harmothoe imbricata (Polychaeta)

Summary Elytra of the scale-worm Harmothoe imbricata were examined for the presence of monoamine-like immunoreactivities and radioautographic reactions. Serotonin (5-HT)-like immunoreactivity was widely distributed among the cellular constituents of the elytra, being present in epithelial cells including photocytes, in elytral nerves, clear cells and the loose neuronal plexus of the middle compartment. The distribution of [³H]5-HT labelling coincided with that of the immunoreactivity except for an additional reactive band extending through the upper cuticle layer. Tyrosine hydroxylase (TH)-like immunoreactivity was detected in epithelial cells, sensory papillae and elytral ganglion and nerves, with little or no staining in clear cells and plexus neurons of the middle compartment. Radioautographic labelling with [³H]noradrenaline and [³H]adrenaline overlaid many epithelial cells, elytral nerves and sensory papillae, but not the loose neuronal plexus or, apparently, clear cells. It is concluded that monoaminergic systems are widely distributed and that they must play important roles as neuroactive and/or paracrine substances in the elytral neuroectoderm. The distribution of [³H]5-HT label in photocytes also suggests the involvement of serotonergic mechanisms in luminescence control, luminescence being the only known effector activity of elytra.     

Three species of the genus Laboulbenia (Laboulbeniales) parasitic on Chydaeus bedeli (Coleoptera, Carabidae) from Asia

Three species of the genus Laboulbenia were recorded on Chydaeus bedeli (Coleoptera, Carabidae, Harpalini) from high-altitude localities in Asia. Laboulbenia obtusa was obtained from tarsi of the midlegs of the male hosts; Laboulbenia acrogeniodontis was on the margins of the elytra of the male and female hosts; and Laboulbenia polyphaga was on the elytra (near the apex) and the pronotum (at the base) of the male and female hosts. Each of the three species is distinct in the shape of the perithecia and the structure of the appendages.     

Comparative morphological study on the genus Leptura Linnaeus of China(Coleoptera: Cerambycidae: Lepturinae)

A comparative morphological research was done based on the morphological characters of 21 species from Leptura in this paper. The results indicated that 18 morphological characters, such as the ratio of the lower eye lobe to genae, the relative length of antennae segments, the shape of maxillary palpi apex, prothorax, elytra apex and elytral maculae can be used to identify species in the genus. Meanwhile, the color of elytra and the size of elytral maculae could not be used to identify species from Leptura. In addition, the shape of 7th abdominally sternal apex, the length of antennae and the ratio of the first hind tarsal segment to the second can be used to distinguish the male and the female.     

Sexual Dichromatism and Female Preference in Eulemur fulvus Subspecies

We experimentally tested the hypothesis that sexual dichromatism in the subspecies of Eulemur fulvus is the evolutionary result of female preference for brightly colored males. Ten female lemurs representing 6 different subspecies of Eulemur fulvus were subjects in the experiment; controls were 4 females of non-sexually dichromatic lemurid taxa. For each taxon we presented photographs of the face of a male of that taxon whose colors had been digitally altered to make him less and more colourful. Median viewing times of the pooled female Eulemur fulvus are significantly correlated with colorfulness. Viewing times in the control females are not correlated with color or brightness of the stimulus photographs. We concluded that the females of the Eulemur fulvus sspp. preferred to view photographs of more colorful males, which is consistent with the predictions of sexual selection theory.     

Identification and laboratory behavioral test of the alarm pheromone of Acanthocoris sordidus Thunberg (Hemiptera: Coreidae)

The winter cherry bug, Acanthocoris sordidus Thunberg (Hemiptera: Coreidae), widely spread in South Korea, Japan and Taiwan, is becoming an economic pest in these regions. Its elevated pest status in pepper plant, Capsicum annuum, is a trigger for eco‐friendly management tactics. In order to use its pheromone for pest management, the cuticular components of adult A. sordidus were identified and a behavioral bioassay on the functions of the components was conducted. From the whole‐body extracts of male and female A. sordidus, 13 compounds (hexanal, 1‐hexanol, 2‐hexanol, 3‐hexanol, hexanoic acid, hexyl acetate, heptyl acetate, octyl acetate, tetradecane, 2‐butyl‐2‐octenal, hexyl hexanoate and (2α,4α,6β)‐2,4,6‐tripentyl‐1,3,5‐trioxane (hexanal trimer, cis‐ and trans‐forms) were identified. In addition to these, two unidentified compounds, a male‐specific and a male‐rich compound, were also found. Hexanal provoked clear escaping behavior. 1‐Hexanol, hexyl acetate and hexanoic acid evoked weaker behavior than hexanal. We concluded that hexanal worked as an alarm pheromone and could be used as a pushing signal for a control program for A. sordidus.     

A new weevil genus of the tribe Metrioxenini (Coleoptera: Belidae) in Eocene Baltic amber

A new genus, Succinometrioxena n. gen., and a new species, S. poinari n. sp. (Metrioxenini: Oxycoryninae), are described from Baltic amber. This new genus resembles the recent genus Wallacexena Legalov, 2009 but differs from it by the frons with horn-like tubercles on either side, the absence of a middle pronotal carina, teeth on the side of the pronotum, the anterior margin of the pronotum lacking teeth and two long carinae on the elytra. From the fossil genus Paltorhynchus Scudder, 1893 the present fossil differs by possessing a frons with horn-like tubercles on either side, the absence of a middle pronotal carina, teeth on the sides of the pronotum, two long carinae on the elytra and short temples. From the fossil genus Archimetrioxena Voss, 1953, the new genus differs by the frons with horn-like tubercles on either side, the absence of the two truncated elytral carinae, the sides of the pronotum with teeth, short temples and a larger body size.     

Indirect closing of elytra by the prothorax in beetles (Coleoptera): general observations and exceptions

Voluntary movements of the prothorax and the elytra in tethered flying beetles and manually induced movements of these parts in fresh dead beetles were recorded in 30 species representing 14 families. Participation of prothoracic elevation in the closing of the elytra was demonstrated in three ways. (i) The elevation was always simultaneous with elytral closing, in contrast to depression and elytral opening; a rare exception occurred in Lucanus cervus, whose elytra sometimes started to close before the cessation of wing strokes and the elevation of the prothorax. (ii) The manipulated elevation always induced closing of the spread elytra; the mechanical interaction between the hind edge of the pronotum and the roots of the elytra is a universal mechanism of closing the elytra in beetles. (iii) The prevention of pronoto-elytral contact in live beetles by the excision of the hind edge of the pronotum in front of the root prevented elytral closing after normal flight. Exceptions to this rule included some beetles that were able to close their elytra after such an excision: tiger beetles and diving beetles (seldomly) and rose chafers (always). This ability in Adephaga may be explained by attachments of the muscle actuating the 4th axillary plate, which differ from the attachments in Polyphaga. Cetoniinae open their elytra only by a small amount. It is proposed that their small direct adductors in combination with the elasticity of the sclerites are enough to achieve elytral closing without additional help from the prothorax.     

Stridulation variability and morphology: an examination in dung beetles of the genus<Emphasis Type="Italic"> Trypocopris</Emphasis> (Coleoptera,Geotrupidae)

Distress signals produced by dung beetles of the genus Trypocopris (Coleoptera, Geotrupidae) were analysed to test whether interspecific and intraspecific acoustic variability are species- and subspecies-specific and to ascertain to what extent bioacoustic parameters depend upon the morphology of the stridulatory organs (pars stridens). Bioacoustic analyses showed that the three species were clearly differentiated, despite the fact that disturbance stridulations presented the same stereotyped spectrographic pattern. Within each species, most of the subspecies and populations considered were also bioacoustically distinguishable. Subspecies and populations within each species were differentiated with regard to body size and stridulatory organ, and the length of the pars stridens was positively correlated with the width of the coxa, in turn positively correlated with body size. A few spectrographic measures were significantly constrained by the morphology of the stridulatory apparatus; in particular the duration of sound emission was positively correlated with the length of the apparatus and the sub-pulse rate was negatively related to the distance between two consecutive crests. For T. pyrenaeus, with the largest number of populations sampled, there was no significant correlation between morphological and spectrographic distances, but there were significant positive correlations between morphological and geographical distances and between morphological and genetic distances. It is hypothesized that genetic differentiation might directly affect variability of the stridulatory apparata which would also be indirectly influenced and constrained by external morphological traits (like the width of the coxa and body size). Stridulatory organs, in turn, would affect the ways a few stridulatory traits (especially the temporal ones) change in time and space.     

The elytra-to-body binding mechanism of the flightless rainforest species Tabarus montanus Kaszab (Coleoptera: Tenebrionidea)

The elytra-to-body binding mechanism of the flightless rainforest species Tabarus montanus Kaszab (Coleoptera: Tenebrionidea) is described. Previously, studies on this complex character system in tenebrionids have focused mostly on either fully-winged or flightless, desert-dwelling species with a hermetically sealed subelytral cavity. Data presented here show that the rainforest species Ta. montanus has permanently joined interlocking macrostructures between the two elytra along the midline and between the elytral epipleuron and the sides of the body. These are very similar adaptations to ones found in flightless desert tenebrionids. Frictional patches of microtrichia, previously reported in all wing-folding beetle suborders including flightless taxa, are completely absent in Ta. montanus. This constitutes the first report of the complete loss of frictional microtrichia patches in a beetle with fully-developed elytra. Sensory organs (hair sensilla), usually involved in the correct positioning of the elytra over the beetles’ body at rest are also absent in Ta. montanus. The significance of these results relating to the evolution of the tenebrionid subelytral cavity is discussed.     

Fine Structure of Elytral Punctures and Diffraction Gratings in Korean Sericinae (Coleoptera, Melolonthidae)

ABSTRACT The surface structures of the elytra in twenty two species belonging to the subfamily Sericinae (Coleoptera, Melolonthidae) were observed by scanning electron microscopy. For viewing specific characters, elytral punctures and diffraction gratings on interstitial surface were focused on. The elytral punctures of observed Sericid beetles have three representative forms: horseshoe, ocellus, and crease types. The diffraction gratings of the elytra show three distinctive patterns: regular and parallel, discontinued, and interconnected and curved. These patterns of elytral punctures and diffraction gratings considered to be useful for identification.     

Interspecific variation in spawning time and male mating tactics of the parrotfishes on a fringing coral reef at Iriomote Island,Okinawa

Spawning time and male mating tactics of parrotfishes (family Scaridae) were investigated on a fringing coral reef at Iriomote Island, Okinawa. Spawning was observed in 14 species, and more frequently in more abundant species such as Chlorurus sordidus, Scarus rivulatus and Chlorurus bowersi. At the reef-edge spawning site, C. bowersi spawned at high tide, C. sordidus spawned both at high tide and in the early morning, whereas Calotomus carolinus and most of the Scarus species such as S. rivulatus spawned only in the early morning, mostly 0630–0830 h. Spawning only in the early morning irrespective of tide phase and moon age has seldom been reported from the scarid species of other localities. It is suggested that spawning in the early morning would be adaptive in species such as S. rivulatus, which migrated considerable distances (ca. 500 m) to the inshore feeding sites, in order to minimize feeding losses due to migration. For male mating tactics, pair spawning by territorial TP (terminal phase) males occurred in all 14 species, and streaking and group spawning by nonterritorial small IP (initial phase) males were seen more frequently in more abundant species. Moreover, group spawning by nonterritorial TP males, which were larger than the IP males but smaller than the territorial TP males, frequently occurred in S. rivulatus. Such mating tactics of TP males have not been reported from Scaridae.     

The oldest genus of the subfamily Sagrinae (Coleoptera: Chrysomelidae) from the Paleocene of Menat (France)

The new oldest representative of the subfamily Sagrinae, Gallopsis perita gen. et sp. n. from the Paleocene of Menat (France), is described and illustrated. It is distinguished from the genus Neodiaphanops Blackburn, 1899 by the metafemora without teeth, wider pronotum, weakly widened tibiae, bilobed tarsomere 2, subparallel elytra, and narrower metanepisterna. It differs from the Australian genus Carpophagus Macleay, 1826 in the head without rostrum, weakly widened metafemora without teeth, and gently sculptured pronotum and elytra. The new genus differs from the Eocene genus Eosagra Haupt, 1950 in the longer antennomere 2, wider pronotum and elytra, dense and diffuse elytral puncturation, and weakly inflated metafemora.