Mating behavior of a flower-visiting longhorn beetle Zorion guttigerum (Westwood) (Coleoptera: Cerambycidae: Cerambycinae)

Long-range sex pheromones have been demonstrated for several cerambycid beetle species. Our field study on the mating behavior of Zorion guttigerum, on the basis of its temporal and spatial distributions on mating and feeding sites (flowers), and longevity, however, suggests that such pheromones are not used by this species. Plant characteristics rather than long-range sex pheromones may play an important role in bringing both sexes together. Adult activities on flowers occur exclusively during the day with two peaks, one around midday and the other in the late afternoon. Overall operational sex ratio is male-biased (1 :1.5 ) but it becomes very highly male-biased (1 :9 ) when mating and feeding activities decrease to the minimum in mid-afternoon, suggesting that females leave flowers to oviposit during that period of time. For cerambycid species whose females oviposit alone, and in which mating and oviposition occur on different plants or different plant parts, the operational sex ratio appears to vary significantly over time on the mating sites. The number and duration of pair-bondings also vary over time for Z. guttigerum. Fewer and shorter pair-bondings in the morning may suggest a strong sexual selection process. After 2 h of selection, both sexes tend to engage in longer pair-bondings and mate more times before females leave the mating sites in mid-afternoon. Details of the mating behavior are described here.     

Discovery of mycangia and the associated xylose-fermenting yeasts in stag beetles (Coleoptera: Lucanidae)

Most wood-feeding insects need an association with microbes to utilize wood as food, and some have special organs to store and convey the microbes. We report here the discovery of the microbe-storage organ (mycangium) in stag beetles (Coleoptera: Lucanidae), which develop in decayed wood. The mycangium, which was discovered in the abdomen, is present in all adult females of 22 lucanid species examined in this study, but absent in adult males. By contrast, adult insects of both sexes of selected Passalidae, Geotrupidae, and Scarabaeidae, which are related to Lucanidae, lacked mycangia similar to those of the lucanid species. Yeast-like microbes were isolated from the mycangium of five lucanid species. DNA sequence analyses indicate that the microbes are closely related to the xylose-fermenting yeasts Pichia stipitis, Pichia segobiensis, or Pichia sp. known from the gut of a passalid species.     

High individual variation in pheromone production by tree-killing bark beetles (Coleoptera: Curculionidae: Scolytinae)

Aggregation via pheromone signalling is essential for tree-killing bark beetles to overcome tree defenses and reproduce within hosts. Pheromone production is a trait that is linked to fitness, so high individual variation is paradoxical. One explanation is that the technique of measuring static pheromone pools overestimates true variation among individuals. An alternative hypothesis is that aggregation behaviour dilutes the contribution of individuals to the trait under selection and reduces the efficacy of natural selection on pheromone production by individuals. We compared pheromone measurements from traditional hindgut extractions of female southern pine beetles with those obtained by aerating individuals till they died. Aerations showed greater total pheromone production than hindgut extractions, but coefficients of variation (CV) remained high (60-182%) regardless of collection technique. This leaves the puzzle of high variation unresolved. A novel but simple explanation emerges from considering bark beetle aggregation behaviour. The phenotype visible to natural selection is the collective pheromone plume from hundreds of colonisers. The influence of a single beetle on this plume is enhanced by high variation among individuals but constrained by large group sizes. We estimated the average contribution of an individual to the pheromone plume across a range of aggregation sizes and showed that large aggregation sizes typical in mass attacks limit the potential of natural selection because each individual has so little effect on the overall plume. Genetic variation in pheromone production could accumulate via mutation and recombination, despite strong effects of the pheromone plume on the fitness of individuals within the aggregation. Thus, aggregation behaviour, by limiting the efficacy of natural selection, can allow the persistence of extreme phenotypes in nature.     

The influence of grassland management on ground beetles (Carabidae, Coleoptera) in Swiss montane meadows

Effects of grassland management type and intensity on carabid species richness, number of individuals and species composition were studied in the Swiss Prealps. Carabids were censused in 2001 and 2002 in 21 mown and 20 grazed meadows by means of pitfall traps.Mean species richness was significantly higher in mown plots than in grazed plots and species composition was significantly different between these two management types. Additionally, different species characteristic for mown and grazed plots were found. These results suggest that mown meadows and grazed meadows represent two habitat types for carabid beetles.Within both habitats, management intensity was quantified by fertilizing intensity, the number of cuts, cattle density and/or grazing intensity. The relationship between management intensity and the number of individuals and species was positive. Higher fertilizing intensity was the most important factor for higher species richness and had a significant influence on species composition in both habitats. Other variables positively related to the number of individuals, were the number of cuts in mown meadows and grazing intensity and altitude in grazed meadows. Additionally to fertilizing intensity, cattle density was positively related to the number of species in grazed meadows. These results illustrate that in the extensive management systems found in the Swiss Alps and Prealps, even intensively managed meadows can sustain high carabid diversity and abundance.     

A review of myrmecophily in ant nest beetles (Coleoptera: Carabidae: Paussinae): linking early observations with recent findings

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.

Localization and density of phoretic deutonymphs of the mite Uropoda orbicularis (Parasitiformes: Mesostigmata) on Aphodius beetles (Aphodiidae) affect pedicel length

The phoretic stage of Uropodina mites is a deutonymph with developed morphological adaptations for dispersal by insects. Phoretic deutonymphs are able to produce a pedicel, a stalk-like temporary attachment structure that connects the mite with the carrier. The aim of our study was to determine whether localization and density of phoretic deutonymphs on the carrier affect pedicel length. The study was conducted on a common phoretic mite—Uropoda orbicularis (Uropodina) and two aphodiid beetles—Aphodius prodromus and Aphodius distinctus. Our results show that pedicel length is influenced by the localization of deutonymphs on the body of the carrier. The longest pedicels are produced by deutonymphs attached to the upper part of elytra, whereas deutonymphs attached to femora and trochanters of the third pair of legs and the apex of elytra construct the shortest pedicels. In general, deutonymphs attached to more exposed parts of the carrier produce longer pedicels, whereas shorter pedicels are produced when deutonymphs are fixed to non-exposed parts of the carrier. A second factor influencing pedicel length is the density of attached deutonymphs. Mean pedicel length and deutonymph densities were highly correlated: higher deutonymph density leads to the formation of longer pedicels. The cause for this correlation is discussed, and we conclude that pedicel length variability can increase successful dispersal.     

Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera)

Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.     

Delayed colonisation of arable fields by spring breeding ground beetles (Coleoptera: Carabidae) in landscapes with a high availability of hibernation sites

The colonisation of winter barley fields by spring breeding carabids and its temporal modulation by the amount of potential hibernation sites was studied. Species richness of carabids was lower in landscapes with high length of boundaries and a high amount of non-cropped open habitats during early stages of the beetles’ colonisation of arable fields. Species number of beetles with high dispersal potential responded to this landscape features at coarse spatial scales whereas beetles with low dispersal potential responded to intermediate scales. However, the negative impact of potential hibernation sites on colonisation diminished in later sampling phases. The patterns observed may be explained by both overwintering in arable soils in less complex landscapes and delayed colonisation in more complex landscapes. The seasonal patterns of landscape control suggest a need to account for temporal dynamics in interactions between species or functional groups and landscape properties. A high temporal resolution is needed in studies that focus on ecosystem function and services in agricultural landscapes, as direction of effect (positive/negative) of management on animal communities may change across spatial scales and within short time periods.     

Grassy field margins and arthropod diversity: a case study on ground beetles and spiders in eastern Austria (Coleoptera: Carabidae; Arachnida: Aranei, Opiliones)

In 1983, the species composition and diversity of carabids, spiders and harvestmen was investigated by pitfall traps in a grassy field margin and in an adjacent, biologically farmed wheat field at Obere Lobau, Vienna, Austria.The carabid fauna of both habitats was diverse; it showed a high degree of similarity, the abundant species in both habitats being represented by typical field species. Only Metophonus spp. predominantly lived in the margin. Numerous species of different habitat origin occurred in the margin at low abundances indicating transitional stay rather than permanent populations.In contrast, the spider fauna showed a low degree of similarity, with few agrobiotic species strongly dominating field fauna. In the field margin, a rich spider fauna containing rare elements indicates the general importance of grassy margins for nature conservation. The apparently low faunal exchange of spiders between the two habitat types is discussed. Harvestmen occurred mainly in the field margin; only two thermophilic species invaded the field.Seasonal fluctuations in the trapping numbers of Bembidion lampros, Platynus dorsalis and Brachinus explodens are interpreted as indicating migrations between field margin and field. Poecilus cupreus and certain other field species, however, apparently spend their entire life cycle in the field. The possible function of field margins for restoration of carabid losses due to impacts of intensive cultivation is discussed.It is concluded that both grassy field margins and sustainable farming methods, in particular biological farming, are necessary to maintain a diverse predatory arthropod fauna in agroecosystems.     

Evidence for contact sex recognition pheromone of the Asian longhorned beetle,<Emphasis Type="Italic"> Anoplophora glabripennis</Emphasis> (Coleoptera: Cerambycidae)

Field observations of the Asian longhorned beetle (Anoplophora glabripennis) mating behavior in China suggested that a female-produced contact pheromone was almost certainly involved in sex recognition. Gas chromatography–mass spectrometry (GC-MS) analysis of A. glabripennis adults' whole body cuticular extracts indicates that a series of long-chain hydrocarbons comprise the cuticular waxes of both sexes. Although for the most part the GC profiles are similar for the two sexes, five monounsaturated compounds were consistently more abundant in samples from females than in those from males. These compounds were identified as (Z)-9-tricosene, (Z)-9-pentacosene, (Z)-7-pentacosene, (Z)-9-heptacosene, and (Z)-7-heptacosene in the approximate ratio of 1:2:2:8:1, respectively. Antennal and palpi contact to a polypropylene micro-centrifuge tube coated with a synthetic mixture of the five compounds stimulated copulatory behavior in males.Electronic Supplementary Material  Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.     

Queue up, please! Spermathecal filling in the rove beetle Drusilla canaliculata (Coleoptera, Staphylinidae)

Most studies on insect sperm motility have been conducted in vitro using artificial environments outside the animal’s body. Only little is known about the function of motile insect sperm at different sites within the male or female genital tracts. We dissected genital tracts of female rove beetles (Drusilla canaliculata) to show that spermatozoa use their own motility to migrate from the spermatophore into the spermatheca. Our dissection method allowed direct observation and filming of the spermathecal filling process inside the female’s genital tract. Spermatozoa were found to enter the spermatheca individually, sometimes in groups of two or three. Although exhibiting only weak motility and no progressive motion in buffer solution, the spermatozoa inside the female show vigorous lashing and reach an average velocity of 47.5 μm s⁻¹. To gain mobility and speed, the spermatozoa likely utilize the relatively small diameter of the spermathecal duct to push themselves off the duct walls, rather than swimming freely in seminal fluid. The spermatozoa (approximately 1,250 μm) are considerably longer than the distance they have to travel along the spermathecal duct (approximately 800 μm). Our study provides the first direct observation of active sperm migration within the female of an insect stressing the importance of the genital tract as a prerequisite for functional sperm motility.     

Sexual contact influences orientation to plant attractant in Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae)

Chemical signals emitted by insects and their hosts are important for sexual communication and host selection. Plant volatiles facilitate the location of suitable hosts for feeding and oviposition, and may moderate responses to sex and aggregation pheromones. While mating has been shown to moderate behavioral responses to pheromones in a number of insects, little is known about the effects of mating on behavioral responses of insects to plant attractants, and even less is known about the mechanisms involved. In this study, mating was shown to decrease behavioral responses of the Colorado potato beetle to a host kairomone within 24 h, and attraction to the kairomone recovers only after 72 h. This decrease in responsiveness also occurs when only contact with the opposite sex is allowed; the effect is not observed with contact among individuals of the same sex. Peripheral olfactory responses to a component of the kairomone correlate with the observed behavioral responses and suggest involvement of antennal receptors in the behavioral change.     

Evidence for a male-produced pheromone in <Emphasis Type="Italic">Tetropium fuscum</Emphasis> (F.) and <Emphasis Type="Italic">Tetropium cinnamopterum</Emphasis> (Kirby) (Coleoptera: Cerambycidae)

(E)-6,10-dimethyl-5,9-undecadien-2-ol (geranyl acetol), termed here fuscol, was identified as a male-produced pheromone emitted by Tetropium fuscum (F.) and Tetropium cinnamopterum Kirby. In field experiments, traps baited with synthetic fuscol alone were not significantly attractive, but the combination of fuscol plus host volatiles (a synthetic blend of monoterpenes plus ethanol) attracted significantly more male and female T. fuscum and female T. cinnamopterum than did host volatiles alone. This is the first homoterpenoid alcohol to be described in the Cerambycidae, and the first pheromone reported from the sub-family Spondylidinae.     

Larval competition in weevils Revena rubiginosa (Coleoptera: Curculionidae) preying on seeds of the palm Syagrus romanzoffiana (Arecaceae)

Inter- and intraspecific local resource competition may lead to the selection of specific adaptive individual characteristics to overcome interference competition. A highly selective scenario is predictable for interference competition among seed preying weevil larvae that live in and feed upon a single host seed. This scenario is found in Syagrus romanzoffiana palm seeds which are predated by Revena rubiginosa (Curculionidae) larvae. Although multiple infestation of one seed by weevil larvae can occur, invariably only one individual survives and develops in each host seed. A strong competition between the first instar larvae in a restricted window of host fruit development stages leads to physical interactions of conspecifics by ovicide or direct fighting using falcate mandibles. The occurrence of this type of mandible is synchronized with fruit development and restricted to instars with probable competition, as infestation occurs only while the endocarp is soft. Only after lignification of the endocarp the larva changes into the next instar. Mandibles of subsequent instars differ markedly from those of the first instar. The new mandibles can scrape the solid endosperm but are unable to perforate and kill conspecifics. These findings give strong evidence for the selective pressure of intraspecific competition, where special behaviour, mandible morphology and synchronization of its changes with the seed development contribute to individual benefit that involves the killing of conspecifics, since one host seed can only maintain a single larva throughout its complete development.     

Issues associated with possible implementation of Non-Invasive Prenatal Testing (NIPT) in first-tier screening: A rapid scoping review

In recent years, as the implementation and use of Non-Invasive Prenatal Testing (NIPT) have increased, the cost of the test has been decreasing. The cost of NIPT is expected to fall further in the upcoming years. As a result of the decreasing cost of NIPT, many jurisdictions may change their prenatal screening policies toward abandoning serum-based screening and instead, implement and support NIPT as the first-tier screening for all women. There are several concerns in replacing first-trimester screening with NIPT. In this scoping review, we aimed to map the existing knowledge about possible issues in the systematic implementation of NIPT as the primary method of first-tier screening and to assess if any jurisdiction has altered its policy and discontinued serum-based prenatal screening in exchange for NIPT. The Medline database (Ovid) and Google Scholar was searched and all the studies discussing, investigating, or reporting on the systematic implementation of NIPT as the primary method of first-tier screening were included. All the studies went through a two-stage screening process and included full-text articles were reviewed. We did not find any articles indicating a country or region that replaced traditional prenatal screening by NIPT. The included articles were charted, and the data about the possible issues in the systematic implementation of NIPT as the primary method of first-tier screening are summarized narratively and presented in tables in four categories. The findings of this scoping review may be informative for stakeholders and policymakers regarding recent changes in NIPT implementation policies around the world and may aid with developing policy for NIPT implementation with a broader perspective.     

Effects of maternal diet and host quality on oviposition patterns and offspring performance in a seed beetle (Coleoptera: Bruchidae)

In seed beetles, oviposition decisions may influence the offspring phenotype because eggs constitute the initial resources available for larval development. We tested the effects of host quality variations (small vs. large seeds of the host plant Calystegia sepium, Convolvulaceae) on oviposition patterns and offspring performance of the seed beetle Megacerus eulophus. We also manipulated the maternal diet: high diet quality vs. low diet quality to evaluate possible interactive effects of the maternal nutritional environment and host quality on oviposition patterns. We further assessed the consequences of egg size variation in offspring size. Female M. eulophus fed with high-quality diet (H-diet) laid more eggs and lived longer than females fed with low-quality diet (P-diet). Fecundity decreased under a low-quality host for both maternal diets. The occurrence of maternal environmental effects on egg size plasticity was detected. Under conditions of low-quality host, mothers fed with the high-quality diet produced bigger eggs in comparison with a high-quality host, whereas females fed with the low-quality diet produced smaller ones. Regardless of these differences observed in egg size depending on the maternal diet, progeny emerging from small seeds (low-quality host) showed a similar performance at emergence. Offspring traits were only significantly affected by host quality. Beetles emerging from large seeds had greater body weight and length than those reared on small seeds. Variations in oviposition patterns in response to host quality are discussed.     

The value of chromosome analysis in cases of neural tube defects: A case of anencephaly associated with fetal DUP(2) (p24→pter)

A family is described in which two anencephalic fetuses were identified in two pregnancies. Autopsy revealed kidney anomalies in both fetuses. Chromosome analysis was performed only on the second fetus, which had a 46,XY,lOq+ karyotype. Parental chromosome analysis showed the maternal karyotype to be 46,XX,t(2;10) (p24;q26) thus demonstrating that the fetus was carrying a duplication 2(p24→pter). Recurrence risks for anencephaly based on the cytogenetic abnormality were much higher than those which would be quoted for isolated anencephaly. This points out the necessity for complete diagnostic studies when a fetus with a neural tube defect is identified. The literature in regard to the 2p duplication phenotype is reviewed. It is possible that the duplication of the distal segment of 2p results in a neural tube defect/kidney anomaly phenotype.