Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters

A phylogenetic parsimony analysis of fifty-four larval characters of Myxophaga (excluding Lepiceridae) resulted in two minimal length cladograms. The monophyly of Torridincolidae, Hydroscaphidae and Microsporidae is supported by several autapomorphies: miniaturization, flattened body with laterally extended tergites, broadened head, scale-like surface structures, broad tentorial bridge, disc-shaped labral sensilla, spiracular gills and pupation in the last larval exuviae. Hydroscaphidae are the sister group of Microsporidae. Larvae of both families are characterized by semi-entognathous mouthparts, tergites with posterior rows of lancet-shaped setae, claws with flattened basal spines and balloon-shaped spiracular gills. The monophyly of all families is supported by autapomorphies. Torridincolidae excluding Delevea is defined as a monophylum by four derived character states: body ovoid, thorax semicircular and as long as abdomen, labral sensilla fused and abdominal sternite IX distinctly reduced and triangular. The monophyly of Torridincolinae (sensu Endrödy-Younga 1997b) is supported by two autapomorphies. The proposed branching pattern suggests that the early representatives of Myxophaga (excluding Lepiceridae) were living in aquatic conditions with a preference for hygropetric habitats. The tendency to live on rocks in running water and miniaturization have played an important role in myxophagan evolution.     

Larval head morphology of Hydroscapha natans (Coleoptera, Myxophaga) with reference to miniaturization and the systematic position of Hydroscaphidae

 The head of third instar larvae of Hydroscapha natans was reconstructed three dimensionally on a computer. This technique allowed a detailed examination and presentation of internal features of a representative of the ’suborder’ Myxophaga, which is characterized by the very small size of the immature stages and adults. Larval character states of H. natans were compared with features found in other representatives of the Coleoptera. The monophyly of the Myxophaga (excluding Lepiceridae) is supported by several autapomorphies of the larval head: a broadened, transverse head, scale-like cuticular surface structures, round and flattened labral sensilla, short antennae with only two antennomeres, a ligula with papillae, and a broadened tentorial bridge. A monophylum comprising the Hydroscaphidae and Microsporidae is characterized by a very unusual semientognathous condition of the mouthparts and an unusual shape and large relative size of the brain. The last common ancestor of the Hydroscaphidae, Torridincolidae, and Microsporidae was probably living in hygropetric habitats. Several apomorphies have evolved in correlation with this peculiar life style. The very dense arrangement of muscles and other internal structures, and the unusual shape and size of the cerebrum have resulted from miniaturization. The overall complexity of the head is not reduced in comparison to larvae of other representatives of Coleoptera. A negative allometric relationship between body size and the size of the brain, and a correlation between brain size and the size of neurons was found in several species of Coleoptera examined. Accepted: 16 December 1997     

Phylogeny and systematics of Sphaeriusidae (Coleoptera: Myxophaga): minute living fossils with underestimated past and present-day diversity

Sphaeriusidae (Coleoptera: Myxophaga) is a group of shiny, blackish and hemispherical riparian beetles, known for their miniaturized bodies. They are worldwide in distribution, but very limited information is available about taxonomic and morphological diversity, and natural and evolutionary history. The aim of this study is to help fill in these gaps. We examined the external morphology of modern representatives using scanning electron microscopy (SEM), and reconstructed the phylogeny of the family using five DNA markers (cytochrome oxidase I, 18S rRNA, 28S rRNA, CAD and wingless). Our results suggest a larger morphological diversity than previously expected, corresponding to the deep genetic divergences of principal lineages. We also examined two inclusions in 99-million-year-old Burmese amber. The integration of all evidence allows us to recognize three genera: the extinct genus †Burmasporum Kirejtshuk, the newly defined genus Bezesporum gen.nov. preserved in Burmese amber (B. burmiticum sp.nov. ) and present in the modern fauna of Southeast Asia, and the genus Sphaerius Waltl with a world-wide distribution. Sphaerius species are morphologically highly uniform, with the exception of species from Australia and South Africa, which share some characteristics with Bezesporum gen.nov. despite being resolved as deeply nested lineages of Sphaerius by DNA data. The presence of Bezesporum gen.nov. in Burmese amber and in recent fauna indicates that Sphaeriusidae largely maintained their specific morphology and specialized riparian lifestyle for at least 100 million years. Therefore, they can be considered an exceptionally conserved group, with a minimum of evolutionary changes over a long period. Our study also demonstrates that the species numbers and fine-scale morphological diversity of Sphaeriusidae are larger than expected in both the past and present-day faunas. Both were apparently underestimated due to the minute body size and cryptic habits of these beetles.     

Morphological integration and pleiotropy in the adaptive body shape of the snail‐feeding carabid beetle Damaster blaptoides

The snail‐feeding carabid beetle Damaster blaptoides exhibits diverse head and thorax morphologies, and these morphotypes are linked with two alternative feeding behaviours. Stout‐shaped beetles feed on snails by crushing the shells, whereas slender‐shaped beetles consume snails by inserting their heads into the shells. A trade‐off exists between these feeding strategies. Because intermediate‐shaped beetles are less proficient in these two behaviours, stout–slender morphological divergence occurs between related species feeding on land snails. To examine the genetic basis of these morphotypes, we conducted morphological analyses and quantitative trait locus (QTL) mapping using backcross offspring between the stout and slender subspecies. The morphological analyses showed that the width and length of the beetle body parts were correlated with each other; in particular, the head width (HW) and thorax length (TL) were strongly negatively correlated. QTL mapping showed that QTLs for HW and TL are located in close proximity to one another on the longest linkage group and that they have positive and negative additive genetic effects. Our results suggest that the adaptive phenotypic sets of a wide head and short thorax and a narrow head and long thorax are based on the closeness of these QTLs. Morphological integration between the head and thorax may play an important role in the adaptive divergence of these beetles.     

Antennal heart morphology supports relationship of Zoraptera with polyneopteran insects

The antennal hearts of the zorapteran Zorotypus hubbardi and of two psocopteran species (Caecilius sp., Embidopsocus sp.) are described in detail and compared to those of other insects. In Zorotypus, the ampullae of this organ are located dorsally of the antennal base. They are attached to the frontal cuticle of the head capsule and laterally suspended by two delicate bands of connective tissue. The associated muscles comprise a well‐developed M. interampullaris and a M. ampulloaortica, which together act as dilators of the ampullae. The connected antennal vessel has a very thin wall and is uniform along its entire length. In the two studied psocopterans the ampullae are likewise connected to the head capsule and have two additional elastic bands. In Caecilius sp. the anterior band is muscular, while in Embidopsocus sp. it is the posterior one. The psocopteran antennal hearts have no additional musculature. Antennal hearts with a musculature configuration resembling that of Zoraptera are known only from Dictyoptera, Phasmatodea and some orthopterans. This condition thus might be a synapomorphy of a polyneopteran subgroup including Zoraptera.     

Effects of habitat complexity on forest beetle diversity: do functional groups respond consistently?

We examined the responses of a beetle assemblage to habitat complexity differences within a single habitat type, Sydney sandstone ridgetop woodland, using pitfall and flight‐intercept trapping. Six habitat characters (tree canopy cover, shrub canopy cover, ground herb cover, soil moisture, amount of leaf litter, and amount of logs, rocks and debris) were scored between 0 and 3 using ordinal scales to reflect habitat complexity at survey sites. Pitfall trapped beetles were more species rich and of different composition in high complexity sites, compared with low complexity sites. Species from the Staphylinidae (Aleocharinae sp. 1 and sp. 2), Carabidae (Pamborus alternans Latreille), Corticariidae (Cartodere Thomson sp. 1) and Anobiidae (Mysticephala Ford sp. 1) were most clearly responsible for the compositional differences, preferring high complexity habitat. Affinities between general functional groupings of pitfall‐trapped beetles and habitat variables were not clear at a low taxonomic resolution (family level). The composition and species richness of flight‐intercept‐trapped beetles were similar in high and low complexity sites. Our study demonstrates that discrete responses of the various functional groups of beetles are strongly associated with their feeding habits, indicated by differing habitat components from within overall composite habitat complexity measures. Although habitat preferences by beetle species may often reflect their foraging habits, clarification of the causal mechanisms underpinning the relationships between habitat complexity and beetles are critical for the development of general principles linking habitat, functional roles and diversity.     

The cephalic morphology of the troglobiontic cholevine species Troglocharinus ferreri (Coleoptera,Leiodidae)

Leiodidae are the second largest subterranean radiation of beetles at family rank. To explore morphological trends linked with troglobiontic habits and characters with potential phylogenetic significance, the head of the cave-dwelling species Troglocharinus ferreri (Cholevinae, Leptodirini) was examined in detail. Overall, the general pattern is similar to what is found in Catops ventricosus (Cholevini). Shared apomorphic features include a fully exposed anterolateral concavity containing the antennal socket, a distinct bead above this depression, a bilobed lip-like structure anterad the labrum, a flat elevated portion of the ventral mandibular surface, and a ventral process at the proximomesal edge of this mandibular area. The tentorial structures are well-developed as in C. ventricosus, with a large laminatentorium and somewhat shortened dorsal arms. The mouthparts are largely unmodified, with the exception of unusually well-developed extrinsic maxillary muscles. Features of T. ferreri obviously linked with subterranean habits are the complete lack of compound eyes, circumocular ridges, and optic lobes. A series of characters is similar to conditions found in other genera of Leptodirini: the head capsule completely lacks a protruding ocular region, a distinct neck is missing, the transverse occipital crest is indistinct, and the antennae are elongate and lack a distinct club. Two different trends of cephalic transformations occur in troglobiontic Leptodirini, with some genera like Troglocharinus and Leptodirus having elongated head capsules and antennae, and others having broadened, more transverse heads. In contrast, the modifications are more uniform in the closely related Ptomaphagini, with a pattern distinctly differing from Leptodirini: the head is transverse, with a distinctly protruding ocular region, a distinct transverse occipital crest, and a very narrow neck region.     

Hoverflies (Diptera: Syrphidae) benefit from a cultivation of the bioenergy crop Silphium perfoliatum L. (Asteraceae) depending on larval feeding type,landscape composition and crop management

相似文献   

Antennal sugar sensitivity in the click beetle Agriotes obscurus

The occurrence of salt‐, sugar‐sensitive neurones and a mechanoreceptor neurone in the antennal hair‐like gustatory sensilla of the click beetle Agriotes obscurus L. (Coleoptera, Elateridae) is demonstrated using the electrophysiological sensillum tip‐recording technique. The stimulating effect of 13 water soluble sugars at 100 mm is tested on the neurones of these sensilla. Sucrose and fructose are the two most stimulating sugars for the sugar‐sensitive neurone, evoking almost 30 spikes s^?1 at 100 mm . The stimulating effect of arabinose, glucose, mannose, maltose and raffinose is three‐ to five‐fold lower, in the range 5.9–9.6 spikes s^?1. The remaining six sugars, xylose, galactose, rhamnose, cellobiose, trehalose and lactose, have very low (<1 spikes s^?1) or no ability to stimulate the sugar‐sensitive neurone. Concentration/response curves of the sugar‐sensitive neurone to sucrose, fructose and glucose at 0.01–100 mm overlap to a large extent in hibernating, cold reactivated and reproductively‐active beetles. A remarkable 9–50% decrease in the number of spikes evoked by 100 mm fructose and 10–100 mm sucrose occurs, however, in reproductively‐active beetles in June compared with beetles at the beginning of hibernation in October. These findings show that A. obscurus is capable of sensing a wide range sugars via their antennal gustatory sensilla.     

On the head morphology of Grylloblattodea (Insecta) and the systematic position of the order,with a new nomenclature for the head muscles of Dicondylia

External and internal head structures of adults of Galloisiana yuasai (Grylloblattodea) are described. The results are compared with conditions found in representatives of other lower neopteran lineages, notably in Austrophasma and Karoophasma (both Mantophasmatodea). Sutures and ridges of the head capsule are discussed. A new nomenclature for head muscles is presented for the entire Dicondylia (= Zygentoma + Pterygota). Galloisiana (like its sister taxon Grylloblatta) is mostly characterized by plesiomorphic features, such as the largely unspecialized orthopteroid mouthparts, the multisegmented filiform antennae, the presence of trabeculae tentorii, the absence of muscles associated with the antennal ampullae, the presence of musculus stipitalis transversalis (0mx11) and the presence of musculus tentoriofrontalis anterior (0te2). Autapomorphies of Grylloblattodea are: (i) compound eyes composed of only 60 ommatidia or less; (ii) a lacinia with a proximal tooth; (iii) a rounded submentum; (iv) loss of musculus craniohypopharyngealis (0hy3); and (v) loss of musculus labroepipharyngealis (0lb5). The phylogenetic evaluation of 104 characters of the head yields a branching pattern with Grylloblattodea as a sister group of Mantophasmatodea in clade Xenonomia. Putative synapomorphies of both taxa are: (i) a distinct angle (more than 60°) between the submentum and the mentum; (ii) posteriorly oriented labial palpi; (iii) a flat and lobe‐like hypopharynx with a suspensorium far ventrad of the anatomical mouth opening; (iv) loss of musculus tentorioparaglossalis (0la6); and (v) a connection between the antennal ampulla and the supraoesophageal ganglion containing nuclei. Xenonomia is placed in a clade with the two dictyopteran terminals. Another monophyletic group is Embioptera + Phasmatodea. Most branches of the single tree obtained in our analysis are weakly supported. The results clearly show that more data and a much broader taxon sampling are required to clarify the phylogenetic interrelationships of the lower neopteran orders. However, our results narrow down the spectrum of possible solutions, and represent a starting point for future phylogenetic analyses, with an extensive concatenated dataset.     

Prefeeding Behavior of the Crucifer Flea Beetle, Phyllotreta cruciferae, on Host and Nonhost Crucifers

The prefeeding behaviours of adult crucifer flea beetles, Phyllotreta cruciferae (Coleoptera: Chrysomelidae: Alticinae), were determined on seedlings of the host plant, Brassica napus, and compared to behaviors on seedlings of the nonhost crucifers, Crambe abyssinica, Sinapis alba, and Camelina sativa. Three stages of prefeeding behaviour, i.e., acclimation, stimulation, and initial feeding, were distinguished through observation of filmed beetles. Both antennal and tarsal chemoreceptors are important in determination of host plant quality by the crucifer flea beetle. The results of this study suggest that the sequence of prefeeding behaviors plays a crucial role in the onset of feeding. Differences in time spent on plant tissue and the frequency and duration of prefeeding behaviors provide insight into possible mechanisms of resistance to flea beetles in the non-Brassica crucifers. The nonpreferred hosts C. abyssinica and S. alba contain deterrent phytochemicals that partially inhibit feeding. These deterrent compounds appear to be volatile in nature in S. alba but nonvolatile in C. abyssinica. CFB resistance in the nonhost C. sativa may result from either the presence of repellent or the absence of stimulatory volatile phytochemicals.     

The larval head morphology of Xyela sp. (Xyelidae, Hymenoptera) and its phylogenetic implications

Larval head structures of Xyela sp. are described in detail. The characters are compared to conditions found in larvae of other groups of Hymenoptera and Endopterygota. Like other symphytan larvae the immature stages of Xyelidae are mainly characterized by presumably plesiomorphic features of the head. The head sutures are well developed and all parts of the tentorium are present. The labrum is free and a complete set of labral muscles is present. The maxillae are in a retracted position. In contrast to other hymenopteran larvae Xyela possesses a clypeofrontal suture, a comparatively long antenna and three well‐developed antennal muscles. Apomorphic features of Xyela are the absence of muscles associated with the salivarium and the complete absence of Musculus craniocardinalis. A clade comprising Orussidae and Apocrita is supported by the unsegmented maxillary and labial palps and the absence of the lacinia. Six potential autapomorphies for the Hymenoptera were revealed: (1) the caudal tentorial apodeme, (2) the bifurcated tendon of Musculus craniomandibularus internus, (3) the lateral lobe of the cardo, (4) the origin of M. tentoriohypopharyngalis from the posterior head capsule, (5) the exceptionally strong prepharyngo‐pharyngeal longitudinal muscle and (6) the longitudinal muscle of the silk press. The maxillolabial complex, the vestigial M. craniocardinalis and a distinctly developed labio‐hypopharyngeal lobe bearing the opening of the salivary duct are potential synapomorphies of Hymenoptera and Mecopterida. The globular, orthognathous head capsule, the modified compound eyes, the occipital furrow and the X‐shaped tentorium are features with unclear polarity shared by Hymenoptera and Mecoptera.     

Survival, longevity and fecundity of overwintering Mesoplatys ochroptera Stål (Coleoptera: Chrysomelidae) defoliating Sesbania sesban (Leguminosae) and implications for its management in southern Africa

1 The defoliator beetle, Mesoplatys ochroptera Stål, is a serious pest of the legume tree sesbania (Sesbania sesban (L.) Merrill) in agroforestry systems in southern Africa. The survival of the overwintering stage of M. ochroptera and post‐ emergence longevity and fecundity of adults in sesbania fallows in eastern Zambia were quantified. 2 Only adult M. ochroptera survived during the winter (May–August) and the dry season (September–October) hidden under weeds, plant litter, in soil cracks and under rocks. During these periods, some beetles were occasionally found feeding on S. sesban, particularly in natural stands in humid areas. The adults were parasitized by the braconid Perilitus larvicida van Achterberg at a rate of 8.5–16.4%. The beetles stayed in the winter refuges for up to 210 days and emerged with the first heavy rains in October–November. The effective survival of beetles overwintering in an insectary was 18.1% in 1998 and 37.7% in 1999, and that of beetles overwintering in the field was estimated at 0.4 and 2.8% in 1998 and 1999, respectively. 3 The post‐emergence longevity and oviposition period of females in the insectary was 14–31 days and 5–29 days, respectively. The post‐emergence fecundity varied from 87 to 783. 4 It is concluded that the serious M. ochroptera infestation observed every year following the rains is due to synchronous emergence of overwintered resident adult populations and their high capacity for reproduction on many species of Sesbania. Recommendations for pest management in sesbania planted‐fallows are given.     

Evolutionary radiation of an inbreeding haplodiploid beetle lineage (Curculionidae, Scolytinae)

Haplodiploidy is a highly unusual genetic system that has arisen at least 17 times in animals of varying lifestyles, but most of these haplodiploid lineages remain relatively poorly known. In particular, the ecological and genetic circumstances under which haplodiploidy originates have been difficult to resolve. A recent molecular‐phylogenetic study has resolved the phylogenetic position of the haplodiploid clade of scolytine beetles as the sister group of the genus Dryocoetes. Haplodiploid bark beetles are remarkable in that the entire clade of over 1300 species are apparently extreme (sib‐mating) inbreeders, most of which cultivate fungi for food while some attack phloem, twigs or seeds. Here we present a much more detailed molecular‐phylogenetic study of this clade. Using partial sequences of elongation factor 1‐alpha and the mitochondrial small ribosomal subunit (12S), we reconstructed the phylogeny for 48 taxa within the haplodiploid clade, as well as two species of the diplodiploid sister genus Dryocoetes. Results indicate that the genus Ozopemon is the basal lineage of die haplodiploid clade. Since Ozopemon, Dryocoetes, and other outgroups are phloem‐feeding, this strongly suggest that haplodiploidy and inbreeding evolved in a phloem feeding ancestor. Following the divergence of Ozopemon there is a series of extremely short internodes near the base of the clade, suggesting a very rapid rate of diversification in early Miocene (based on fossil evidence and sequence divergence). Among the many substrates for breeding and food resources utilized within this species‐rich clade, the cultivation of yeast‐like ambrosia fungi in tunnels deep into the wood predominates (nearly 90% of the species). The number of transitions to feeding on such fungi was few, possibly only one, and is perhaps an irreversible transition. The habit of feeding on fungi cultured in xylem makes it possible for the beetles to use a great variety of plant taxa. This extreme resource generalism, in conjunction with the colonization advantage conferred by haplodiploidy and inbreeding, may have promoted the rapid diversification of this clade.     

Mate finding in the forest cockchafer, Melolontha hippocastani, mediated by volatiles from plants and females

The response of the forest cockchafer, Melolontha hippocastani F. (Coleoptera, Scarabaeidae), towards volatiles emitted by different host plants and conspecifics was tested in field experiments during the flight period at dusk. Funnel traps containing artificially damaged leaves from the host plants Carpinus betulus L. and Quercus rubra L., as well as from the non‐host plant Prunus serotina Ehrh. caught significantly more beetles than empty control traps. On the other hand, traps baited with undamaged leaves from Q. rubra did not catch significantly more beetles than empty controls. Leaves from C. betulus damaged by beetle feeding did not attract more beetles than artificially damaged leaves. By use of gas chromatography coupled with electroantennographic detection (GC‐EAD) electrophysiological responses of males and females were shown for 18 typical plant volatiles. A synthetic mixture of selected typical green plant volatiles was also highly attractive in the field. A total of 9982 beetles was caught during the field experiments, among them only 33 females. This suggests that attraction to damaged foliage during flight period at dusk is male‐specific. Field experiments testing the attractiveness of female M. hippocastani towards conspecific males by employing caged beetles and beetle extracts indicated that males of M. hippocastani use a female‐derived sex pheromone for mate location. On wired cages containing either unmated feeding females, or unmated females without access to foliage, or feeding males in combination with extracts from unmated females, significantly more males landed during the flight period than on comparable control cages containing feeding males or male extracts. A possible scenario of mate location in M. hippocastani involving feeding‐induced plant volatiles and a female‐derived sex pheromone is discussed.     

Phylogeny and life history evolution of Prodoxus yucca moths (Lepidoptera: Prodoxidae)

Abstract. Yucca moths (Lep., Prodoxidae) are well‐known for their obligate pollination mutualism with yuccas. In addition to the pollinators, yuccas also host many non‐pollinating yucca moths. Here the genus Prodoxus, the non‐pollinating sister group of the pollinators, is revised using morphological and molecular data, their phylogenetic relationships are analysed, and the evolution of host tissue specialization explored. Twenty‐two species are recognized, including nine new species: Prodoxus gypsicolor sp.n. , P. sonorensis sp.n. , P. carnerosanellus sp.n. , P. tamaulipellus sp.n. , P. weethumpi sp.n. , P. tehuacanensis sp.n. , P. californicus sp.n. , P. mapimiensis sp.n. and P. atascosanellus sp.n. Prodoxus y‐inversus Riley, P. coloradensis Riley and P. sordidus Riley are redescribed. The genus Agavenema is synonymized with Prodoxus. Phylogenetic analyses indicated that stalk‐feeding is basal within the group, that there are three separate origins of fruit‐feeding, and one origin of leaf‐mining from a stalk‐feeding ancestor. Although species with different feeding habits often coexist within hosts, the analyses suggest that ecological specialization and diversification within a host only may have occurred within one or possibly two hosts.     

Does dimethyl sulfoxide increase protein immunomarking efficiency for dispersal and predation studies?

Marking biological control agents facilitates studies of dispersal and predation. This study examines the effect of a biological solvent, dimethyl sulfoxide (DMSO), on retention of immunoglobulin G (IgG) protein solutions applied to Diorhabda carinulata (Desbrochers) (Coleoptera: Chrysomelidae), an important biological control agent of saltcedar, either internally by feeding them protein‐labeled foliage or externally by immersing them in a protein solution. In addition, we determined whether internally or externally marked DMSO‐IgG labels could be transferred via feeding from marked D. carinulata to its predator, Perillus bioculatus (Fabricius) (Heteroptera: Pentatomidae). The presence of rabbit and chicken IgG proteins was detected by IgG‐specific enzyme‐linked immunosorbent assays (ELISA). DMSO‐IgG treatments showed greater label retention than IgG treatments alone, and this effect was stronger for rabbit IgG than for chicken IgG. Fourteen days after marking, beetles immersed in rabbit IgG showed 100% internal retention of label, whereas beetles immersed in chicken IgG showed 65% internal retention. Immersion led to greater initial (time 0) label values, and longer label retention, than feeding beetles labeled foliage. The DMSO‐IgG label was readily transferred to P. bioculatus after feeding on a single marked prey insect. This investigation shows that addition of DMSO enhances retention of IgG labels, and demonstrates that protein marking technology has potential for use in dispersal and predator–prey studies with D. carinulata. Moreover, our observation of P. bioculatus feeding on D. carinulata is, to our knowledge, a new predator–prey association for the stink bug.