Spectral correspondence between visual spectral sensitivity and bioluminescence emission spectra in the click beetle Pyrophorus punctatissimus (Coleoptera: Elateridae)

The presence of two spectral mechanisms, near-ultraviolet and green (lambda(max)=545nm), is strongly suggested by electroretinographic visual spectral sensitivity curves obtained under dark and red chromatic adaptation conditions in the compound eyes of the click beetle Pyrophorus punctatissimus. The bioluminescence emission of the dorsal prothoracic lanterns is deep green (lambda(max)=543nm) and that of the ventral abdominal lantern is lime green (lambda(max)=556nm) in colour in P. punctatissimus. A broad green visual receptor would detect both deep green and lime green bioluminescent optical signals.     

Phylogenetic relationships of click beetles (Coleoptera: Elateridae) inferred from 28S ribosomal DNA: insights into the evolution of bioluminescence in Elateridae

Although the taxonomy of click beetles (family Elateridae) has been studied extensively, inconsistencies remain. We examine here the relationships between species of Elateridae based on partial sequences of nuclear 28S ribosomal DNA. Specimens were collected primarily from Japan, while luminous click beetles were also sampled from Central and South America to investigate the origins of bioluminescence in Elateridae. Neighbor-joining, maximum-parsimony, and maximum-likelihood analyses produced a consistent basal topology with high statistical support that is partially congruent with the results of previous investigations based on the morphological characteristics of larvae and adults. The most parsimonious reconstruction of the "luminous" and "nonluminous" states, based on the present molecular phylogeny, indicates that the ancestral state of Elateridae was nonluminous. This suggests that the bioluminescence in click beetle evolved independent of that of other luminous beetles, such as Lampyridae, despite their common mechanisms of bioluminescence.     

New click beetles (Coleoptera: Elateridae) from the cretaceous of Russia and Kazakhstan

A new tribe, two new genera, and seven new species of click beetles are described: Pollostelaterini, trib. nov., Pollostelater baissensis, gen. et sp. nov. from the Lower Cretaceous of Transbaikalia (Baisa locality), five new species in the genus Cryptocoelus Dolin et Nel C. sinitshenkovae, sp. nov. (Romanovka locality), C. shcherbakovi, sp. nov., C. baissensis, sp. nov., C. lukashevichae, sp. nov., C. dolini, sp. nov. (all from Baisa locality), and Turonelater giganteus, gen. et sp. nov. from the Turonian of Southern Kazakhstan (Kzyl-Dzhar locality).     

Electroretinogram and the spectral sensitivity of the compound eyes in the firefly Photuris versicolor (Coleoptera-Lampyridae): A correspondence between green sensitivity and species bioluminescence emission

ERGs were recorded from the dorsal sector of dark- and chromatic-adapted compound eyes in the dark-active firefly Photuris versicolor ♀ and ♂ at different wavelengths across the spectrum ranging from 320 nm to 700 nm over 4.5 log units of change in the stimulus intensity. ERG elicited by white light stimulus was an on-negative monophasic wave typical of scotopic eyes. ERGs elicited by chromatic stimuli differed in their waveform characteristics in the short (near-u.v. and violet) and long (green-yellow) wavelengths. The slope of the intensity-response curves at different stimulus wavelengths were similar for phasic response and differed for the plateau component of the ERG. The spectral sensitivity curves obtained under dark- and chromatic-adapted conditions revealed peaks in the near-u.v. (λ_max, 380 nm) and in the green (λ_max 550 nm), suggesting the presence of at least two receptor types in the dorsal sector of the compound eyes of P. versicolor. The green (550 nm) peak corresponds with the species bioluminescence emission peak (552 nm).     

Notes on the fauna and taxonomy of the click beetles (Coleoptera,Elateridae) of Russia and neighboring countries

New data on the distribution and taxonomy of some species of click-beetles in Russia and adjacent countries are given. Several species are recorded for the first time for the following territories: Brachygonus bouyoni (Chass.), B. dubius (Plat. et Cate) and Zorochros lewisi (Schw.), for Russia; Sericus sulcipennis (Baudi), for Ukraine; Berninelsonius hyperboreus (Gyll.), Cidnopus parallelus (Motsch.), and Limonius poneli Les. et Mertl., for Kazakhstan. New interesting findings of Sericus sulcipennis and Selatosomus songoricus (Kr.) are reported. Comments on some erroneous faunistic records of several elaterids, including some species from Middle Asia, are made. The following new synonymy is established: Haterumelater fulvago (Marseul, {dy1868}) = Elater tauricola Gurjeva, 1957, syn. n. Notes on the variability of Selatosomus latus (F.) are given, and its conspecificity with S. corpulentus (Cand.) is confirmed. The external morphology and genitalia of the little known Selatosomus nanus Gur. are studied, and the systematic position of this species is discussed.     

Antennal sensilla of the click beetle,Melanotus villosus (Geoffroy) (Coleoptera: Elateridae)

The typology, number and placement of antennal sensilla of the click beetle Melanotus villosus (Geoffroy) (Coleoptera: Elateridae) were studied using scanning electron microscopy. On both the males and females the antennae are made up of the scape, pedicel and nine flagellomeres. Two types of basiconic sensilla, three types of trichoid sensilla, one type of styloconic sensilla, one type of chetoid sensilla, dome-shaped sensilla, grooved pegs, and Böhm sensilla all appear on the antennae of the beetles of both sexes, with the exception of trichoid sensilla type II, whose large number (average of 1635 hairs per antenna) was found only in male beetles. Sensilla trichodea type II evidently respond to the sex pheromone produced by the female beetle. Unlike the other two click beetles, studied up till now, Agriotes obscurus and Limonius aeruginosus, the trichoid and basiconic sensilla of M. villosus, whose proven or assumed function is olfactory, are located predominantly on the flagellomeres ventral extensions. It is assumed that the placement of the olfactory sensilla, mainly on the ventral side of M. villosuss antennae, and their more or less even distribution on the flagellomeres, can be seen as morphological adaptation of this species of insect, whose specific behavioural reaction of olfactory searching is flying, both before and after contact with an odour plume.     

Microbial population of the digestive tract of click beetle larvae (Elateridae,Coleoptera)

The composition and functional structure of the intestinal microflora of three wireworm species (Agriotes obscurus (L.), Selatosomus aeneus (L.), and Ampedus pomorum (Herbst)) with different dietary regimes were studied. The total abundance of the microorganisms was evaluated by fluorescent microscopy, the group composition was assessed by inoculation on a solid glucose-peptone-yeast medium, and the functional diversity was estimated by multisubstrate testing. It was noted that, in the intestine of the larvae, the total number of microorganisms was lower by 1–2 orders of magnitude than in the soil and decaying wood. It was found that the composition of the intestinal microbial communities of wireworms was radically different from that of the substrate: the Bray-Curtis coefficient did not exceed 0.25. It was found that native forms accounted for more than half of the total number of saprotrophic bacteria: in the larvae, Gram-positive cocci, enterobacteria, Vibrionaceae, Acinetobacter, and some genera of coryneform bacteria, which were absent in the soil and wood, prevailed. The micromycetes were either absent (Agriotes) or were found in insignificant quantities (Selatosomus, Ampedus). In Selatosomus, apart from the intestinal forms, representatives of Mezorhizobium, Nocardioides, and Erwinia, occurring on plant substrates, were observed.     

The jump of the click beetle (Coleoptera, Elateridae)—a preliminary study

A preliminary account is given of the jump of the click beetle, Athous haemorrhoidalis (F.). The jump is normally made from an inverted position. It involves a jack-knifing movement whereby a prosternal peg is slid very rapidly down a smooth track into a mesosternal pit. The muscles which produce this movement are allowed to build up tension by a friction hold on the dorsal side of the peg. The anatomy of this jumping mechanism is briefly described. Ciné recording showed that the jump was usually nearly vertical and could exceed 0.3m in height; the beetle normally rotated several times head over tail during a jump. The jump was produced by a very rapid upwards movement of the beetle's centre of gravity during the jack-knifing action. In a typical jump, a 4 × 10⁻⁵ kg beetle could be subjected to an upwards acceleration of 3800 m/s⁻² (380 g). The minimum work done and the power output of the muscles causing jumping have been calculated. A simple mechanical model has been constructed to simulate a jump, and several possible ways in which the jumping mechanism could operate have been discussed.     

Isolation and characterization of novel dinucleotide repeat microsatellites in the Jamaican click beetle Pyrophorus plagiophthalamus (Coleoptera: Elateridae)

We report 10 polymorphic microsatellite loci for the Jamaican click beetle, Pyrophorus plagiophthalamus. A survey of 36 individuals from three populations in Jamaica showed that these are highly variable, with three to 17 alleles per locus. Observed heterozygosity ranged from 0.250 to 0.917, and mean heterozygosity from 0.601 to 0.747. Most loci were in Hardy–Weinberg equilibrium, although excess of homozygotes was observed in four tests (out of 20), suggesting the possibility of null alleles. Significant linkage disequilibrium was observed for only one pair. These newly developed markers will be useful in understanding the population structure of click beetles in Jamaica, and in identifying possible selective factors responsible for bioluminescent colour variation.     

Contribution to the knowledge of the click beetle genus Zorochros (Coleoptera: Elateridae) from Saudi Arabia

Examination of specimens of Elateridae revealed new generic and species records for Saudi Arabia. Zorochros amalec (Peyerimhoff) is recorded from Al Majardah, and Zorochros yosrae sp. n. is described as a new species from Thalouth Almanazar.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:E4B9EB99-BE55-4884-B220-BF9928926312     

Cold resistance in two species of cave-dwelling beetles (Coleoptera: Cholevidae)

Supercooling points (SCPs), lower lethal temperatures (LLTs), and the effect of short-term exposures (1 min) to low temperatures were examined in the adults of two stenothermal leptodirin species, Neobathyscia mancinii and Neobathyscia pasai (Coleoptera, Cholevidae). Specimens were collected from two caves in the Venetian Prealps (NE-Italy). Inter-species comparison highlighted lower values of SCP in N. mancinii (−7.1±0.9 °C) than in N. pasai (−6.4±0.3 °C), with no significant intersexual differences in both species. N. pasai (LLT₅₀±SE=−16.96±2.30 °C; LLT₁₀₀=−25.41 °C) tolerated short exposures to subzero temperatures better than N. mancinii (LLT₅₀±SE=−4.89±1.08 °C; LLT₁₀₀=−11.72 °C). According to the mortality and cumulative proportion of individual freezing curves (CPIF), SCPs and LLT₁₀₀, N. pasai may be defined as “strongly freeze tolerant”, N. mancinii as “moderately freezing tolerant”. Overall, these results may justify the different in-cave habitat selection showed by the two species (N. pasai was abundant close to the entrance where the temperature is variable whereas N. mancinii was confined to the internal part of the cave where the temperature is constant throughout the year), and suggest hypotheses on the effects of such habitat selection on freeze tolerance strategy adopted. Finally, they give new insights into possible responses to climate changes in cave dwelling species.     

Tuning of photoreceptor spectral sensitivity in fireflies (Coleoptera: Lampyridae)

Sexual communication between male and female fireflies involves the visual detection of species-specific bioluminescent signals. Firefly species vary spectrally in both their emitted light and in the sensitivity of the eye, depending on the time when each is active. Tuning of spectral sensitivity in three firefly species that occupy different photic niches was investigated using light and electron microscopy, microspectrophotometry, and intracellular recording to characterize the location and spectral absorption of the screening pigments that filter incoming light, the visual pigments that receive this filtered light, and the visual spectral sensitivity. Twilight-active species had similar pink screening pigments, but the visual pigment of Photinus pyralis peaked near 545 nm, while that of P. scintillans had a λ_max near 557 nm. The night-active Photuris versicolor had a yellow screening pigment that was uniquely localized, while its visual pigment was similar to that of P. pyralis. These results show that both screening and visual pigments vary among species. Modeling of spectral tuning indicates that the combination of screening and visual pigments found in the retina of each species provides the best possible match of sensitivity to bioluminescent emission. This combination also produced model sensitivity spectra that closely resemble sensitivities measured either with electroretinographic or intracellular techniques. Vision in both species of Photinus appears to be evolutionarily tuned for maximum discrimination of conspecific signals from spectrally broader backgrounds. Ph. versicolor, on the other hand, appears to have a visual system that offers a compromise between maximum sensitivity to, and maximum discrimination of, their signals. Accepted: 29 September 1999     

Peculiarities of the biotope distribution of click beetle larvae (Coleoptera, Elateridae) in the Irtysh River valley

The spatial distribution of Elateridae larvae in the Lower Irtysh valley has been analyzed. The larvae analyzed belonged to 19 Elateridae species inhabiting soils of the floodplain and the river terrace. It has been pointed out that the larvae of Paraphotistus nigricornis, Agriotes lineatus, Limonius parallelus, and Aplotarsus incanus are most tolerant to the regular spring flooding. It has been found that the species compositions of floodplains and terrace meadows are significantly different. As a rule, species with a wide tropical spectrum inhabit floodplain soils, including bush and forest habitats. At the same time, the terrace was dominated by species characteristic of open habitats, including the steppe zone. It has been revealed that the values of species diversity vary significantly in the floodplain and terrace plots, but the higher species richness (Menhinick index) was registered in the floodplain.     

Distribution of olfactory and some other antennal sensilla in the male click beetle Agriotes obscurus L. (Coleoptera : Elateridae)

The distribution of 5 types of sensilla was statistically analysed on the 4–10th antennal segments of the male click beetle Agriotes obscurus (Coleoptera : Elateridae). The distribution pattern of the trichoid pheromone receptors (T₂ sensilla) and the olfactory basiconic B₁B₂ sensilla on the antennae of male A. obscurus differs significantly from the distribution pattern of the contact chemoreceptors (T₁ sensilla) and probably the non-olfactory B₇ and D sensilla. A significant peculiarity of the distribution of olfactory sensilla is their location on the antennal segments as 2 separate (dorsal and ventral) fields of sensilla. The numbers of T₂ and B₁B₂ sensilla on dorsal fields of sensilla of the 4–10th segments increase towards the apex of the antenna nearly linearly. On ventral fields of sensilla of the 4–10th antennal segments, the number of B₁B₂ sensilla is nearly uniform; the number of T₂ sensilla in the proximal part of the antenna increases towards the apex, but on distal segments of the antenna their number stabilizes. It is characteristic of both the T₂ and to B₁B₂ sensilla that their numbers are slightly greater on anterior than posterior sides of dorsal sensillar fields, and also greater on posterior than anterior sides of ventral sensillar fields of all antennal segments investigated. We assume that the number of olfactory sensilla on the antennae of male beetles coincides with the distribution of strength of olfactory signal on the antennae of beetles orientating in an odour plume. The distribution patterns of T₂ and B₁B₂ sensilla of the male A. obscurus can be related to some behavioural peculiarities of olfactory orientation (walking or flying and vibrating of the antennae).     

Comparative karyology of seven species of staphylinoid beetles (Polyphaga: Coleoptera)

The morphology of chromosomes of two species of Silphidae and five species of Staphylinidae and the behaviour of chromosomes in mitosis and meiosis were studied. These staphylinoid beetles did not exhibit a modal karyotype. However, Xy_p was found to be the most common male sex-chromosome mechanism althoughPhilonthus varius andQuedius fuliginosus possessed XO. Dicentric chromosomes were found inPhilonthus fuscipennis. Dicentrics were also found in both European and one East Siberian populations ofPhosphuga atrata.In the seven species, the diploid chromosome number ranged from 2n=24 to 2n=56. The evolution of karyotype and the interrelationships between species are dicussed.     

Geranyl hexanoate attracting male click beetles Agriotes rufipalpis Brullé and Agriotes sordidus Illiger (Col., Elateridae)

Abstract: In field screening tests in Hungary, traps baited with geranyl hexanoate captured males of the click beetle Agriotes rufipalpis Brullé, whereas in Italy males of Agriotes sordidus Illiger (Col., Elateridae) were captured. Geranyl hexanoate‐baited traps could be very useful in rationalizing the control of these pests. Such traps can give useful information without making expensive and time‐consuming samplings of the soil layers in search of larvae. Traps can be effective also in describing swarming patterns and identifying the peak of male activity, thus yielding an estimate of the level of adult populations, making it possible to forecast future outbreaks and to concentrate agronomic and chemical control strategies against the pests most effectively.     

C-value estimates for 31 species of ladybird beetles (Coleoptera: Coccinellidae)

This study provides C-value (haploid nuclear DNA content) estimates for 31 species of ladybird beetles (representing 6 subfamilies and 8 tribes), the first such data for the family Coccinellidae. Despite their unparalleled diversity, the Coleoptera have been very poorly studied in terms of genome size variation, such that even this relatively modest sample of species makes the Coccinellidae the third best studied family of beetles, behind the Tenebrionidae and Chrysomelidae. The present study provides a comparison of patterns of genome size variation with these two relatively well-studied families. No correlation was found between genome size and body size in the ladybirds, in contrast to some other invertebrate groups but in keeping with findings for other beetle families. However, there is some indication that developmental time and/or feeding ecology is related to genome size in this group. Some phylogenetic patterns and possible associations with subgenomic features are also discussed.     

Habitat segregation in four species of adult tiger beetles (Coleoptera: Cicindelidae)

ABSTRACT.

• 1 Habitat segregation in four species of tiger beetles, Cicindela cancellata Dejean, C.cardoni Fleutians, C.minuta Olivier and C.sumatrensis Herbst in a river bank ecosystem was studied in dry and wet seasons.
• 2 The four species segregated distinctly along the river beds into separate habitats, with occasional overlapping in both the seasons.
• 3 Among the habitat characteristics considered, vegetation, soil moisture and available prey-size were found to be important in species segregation.
• 4 D ²-analysis showed that the habitat preferences of C.cardoni and C.cancellata were closer to that of C.sumatrensis. The habitat of C.minuta was distinctly separated.
• 5 There was a positive correlation between the mandible length of each tiger beetle species and the length of prey captured.
• 6 Variance in mandible length within species was related to prey-length distribution pattern and to variance in habitats.