粪食性金龟的行为及其适应演化

粪食性金龟的行为简单分为3类:粪居型(endocoprid或dwelling behaviour)、直接掘洞型(paracoprid或tunnelling behaviour)和滚粪球型(telocoprid或rolling behaviour)。文章详细阐述各类型的特点,探讨粪食性金龟行为的进化趋势和过程,并进一步阐述粪食性金龟的适应演化。     

New species of scarabaeoid beetles from the family Glaresidae (Coleoptera: Scarabaeoidea) from the Cretaceous of Transbaikalia

A new species from the family Glaresidae, Cretoglaresis ovalis, sp. nov., is described from the Lower Cretaceous site Baisa in Transbaikalia. Improved diagnosis of the genus Cretoglaresis Nikolajev, 2007 is given.     

The fossil record and macroevolutionary history of the beetles

Coleoptera (beetles) is the most species-rich metazoan order, with approximately 380 000 species. To understand how they came to be such a diverse group, we compile a database of global fossil beetle occurrences to study their macroevolutionary history. Our database includes 5553 beetle occurrences from 221 fossil localities. Amber and lacustrine deposits preserve most of the beetle diversity and abundance. All four extant suborders are found in the fossil record, with 69% of all beetle families and 63% of extant beetle families preserved. Considerable focus has been placed on beetle diversification overall, however, for much of their evolutionary history it is the clade Polyphaga that is most responsible for their taxonomic richness. Polyphaga had an increase in diversification rate in the Early Cretaceous, but instead of being due to the radiation of the angiosperms, this was probably due to the first occurrences of beetle-bearing amber deposits in the record. Perhaps, most significant is that polyphagan beetles had a family-level extinction rate of zero for most of their evolutionary history, including across the Cretaceous–Palaeogene boundary. Therefore, focusing on the factors that have inhibited beetle extinction, as opposed to solely studying mechanisms that may promote speciation, should be examined as important determinants of their great diversity today.     

Diversity of litter-dwelling beetles in the Ouachita Highlands of Arkansas, USA (Insecta: Coleoptera)

A survey of forest litter-inhabiting Coleoptera was conducted in deciduous forests of the Ouachita Mountains in western Arkansas during 1991–1992. A total of 102 Berlese samples were collected, weighed, and processed during the 12-month study. From 741kg of sifted forest litter, we counted and sorted 10663 adult beetles representing 46 families and 400 species. The family Staphylinidae was taxonomically and numerically dominant, comprising 46% of species and 63% of individuals. Problems in assessing species richness of forest litter Coleoptera faunas result from a lack of taxonomic revisions, occurrence of sex-limited diagnostic characters, and inadequate information about larval-adult species associations and life histories. A randomized species accumulation curve indicated that species addition ranged from 14 species per sample during the first ten samples to 1.5 species per sample during the final ten. Richness estimates generated from the empirical data ranged from 434 species (Michaelis–Menten and Coleman richness estimators) to 590 species (second order jacknife). The area sampled is biogeographically significant because it harbors numerous habitat- restricted species that are endemic to the Ouachita Mountains or the Interior Highland region, as well as disjunct populations of species that are also found in the southern Appalachian Mountains. Deciduous forest habitats of the Ouachita Mountains, particularly beech-maple riparian forest, should be given special consideration in forest conservation planning because of their significance as refugia for these and other endemic and disjunct arthropods.     

Discovery of a novel Bacillus thuringiensis Cry8D protein and the unique toxicity of the Cry8D-class proteins against scarab beetles

A novel cry gene, cry8Db, highly toxic to scarab beetles such as the Japanese beetle, Popillia japonica Newman, was cloned from an isolate of Bacillus thuringiensis(Bt), BBT2-5. The cry8Db gene has 3525 bp nucleotides and codes for a protein of 1174 amino acid residues. The protein, Cry8Db, has typical Bt characteristics such as the 8-block, conserved sequences and the three-domain 3 D toxin structure as defined with Cry3Aa. When the amino acid sequence of Cry8Db was compared with that of Cry8Da whose gene was cloned and characterized in our laboratory earlier, substantial sequence diversities were found in their Domain III. The cry8Db gene was expressed in an acrystalliferous B. thuringiensis strain, BT51. BT51 expressing cry8Db formed a spherical crystal like the natural crystal of BBT2-5. The Cry8Db protein was assayed along with the other scarab active Cry8Da and Cry8Ca against the Japanese beetle. While Cry8Da and Cry8Db had toxicity against both adults and larvae of the Japanese beetle, Cry8Ca was toxic to only larvae. Cry8Ca showed no toxicity against the adult beetle up to 30 μg per 1 cm² of leaf discs on which the protein was applied. The activation process of Cry8Db by adult and larval gut juice was compared in vitro with the processes of Cry8Da and Cry8Ca. All three proteins, Cry8Db, Cry8Da and Cry8Ca, produced a toxic core of approximately 70 kDa equally indicating that the activation process does not inactivate the adult activity of Cry8Ca. We concluded that the adult activity of Cry8D proteins is encoded in Domain II. Further tests against other beetle species showed a significant difference between Cry8D’s and Cry8Ca but no difference between Cry8Da and Cry8Db. Comparison of 3D structural models of Cry8Ca, Cry8Da and Cry8Db, which were constructed by using Cry3Bb as the structural template, indicated significant structural differences, especially between Cry8Ca and Cry8D proteins, in three major surface-exposed loops of Domain II that may be involved in determining the adult beetle activity.     

Absence of mammals and the evolution of New Zealand grasses

Anthropogenic alteration of biotic distributions and disturbance regimes has dramatically changed the evolutionary context for the differentiation of species traits. Some of the most striking examples in recent centuries have been on islands where flightless birds, which evolved in the absence of mammalian carnivores, have been decimated following the widespread introduction of exotic predators. Until now, no equivalent case has been reported for plants. Here, we make use of robust analytical tools and an exceptionally well-sampled molecular phylogeny to show that a majority of New Zealand danthonioid grasses (Poaceae) may have adapted to the relaxed vertebrate herbivore pressure during the late Cenozoic through the development of a distinctive and unusual habit: abscission of old leaves. This feature occurs in only about 3 per cent of the world''s roughly 11 000 grass species and has been empirically shown to increase plant productivity but to reduce protection against mammal grazing. This result suggests that release from a selective pressure can lead to species radiations. This seemingly anachronistic adaptation may represent an overlooked factor contributing to the severe decline in the geographical extent and species diversity of New Zealand''s indigenous grasslands following the introduction of herbivorous terrestrial mammals in the 19th century.     

New species of Late Eocene dermestid beetles (Coleoptera, Dermestidae) from the Rovno and Baltic ambers

Fossil beetles of the family Dermestidae are reviewed. Three new species are described: Dermestes progenitor and Megatoma electra from the Baltic amber and Dermestes vetustus from the Rovno amber (Late Eocene).     

Evidence for the monophyletic evolution of benzylisoquinoline alkaloid biosynthesis in angiosperms

Benzylisoquinoline alkaloids (BIAs) consist of more than 2500 diverse structures largely restricted to the order Ranunculales and the eumagnoliids. However, BIAs also occur in the Rutaceae, Lauraceae, Cornaceae and Nelumbonaceae, and sporadically throughout the order Piperales. Several of these alkaloids function in the defense of plants against herbivores and pathogens - thus, the capacity for BIA biosynthesis is expected to play an important role in the reproductive fitness of certain plants. Biochemical and molecular phylogenetic approaches were used to investigate the evolution of BIA biosynthesis in basal angiosperms. The occurrence of (S)-norcoclaurine synthase (NCS; EC 4.2.1.78) activity in 90 diverse plant species was compared to the distribution of BIAs superimposed onto a molecular phylogeny. These results support the monophyletic origin of BIA biosynthesis prior to the emergence of the eudicots. Phylogenetic analyses of NCS, berberine bridge enzyme and several O-methyltransferases suggest a latent molecular fingerprint for BIA biosynthesis in angiosperms not known to accumulate such alkaloids. The limited occurrence of BIAs outside the Ranunculales and eumagnoliids suggests the requirement for a highly specialized, yet evolutionarily unstable cellular platform to accommodate or reactivate the pathway in divergent taxa. The molecular cloning and functional characterization of NCS from opium poppy (Papaver somniferum L.) is also reported. Pathogenesis-related (PR)10 and Bet v 1 major allergen proteins share homology with NCS, but recombinant polypeptides were devoid of NCS activity.     

Ability of stress‐related volatiles to attract and induce attacks by Xylosandrus germanus and other ambrosia beetles

• 1 Xylosandrus germanus typically colonizes physiologically‐stressed deciduous hosts but it is increasingly being recognized as a key pest of ornamental nursery stock. We tested the attractiveness of common plant stress‐related volatiles to ambrosia beetles occupying the nursery agroecosystem, as well as their ability to induce attacks on selected trees. Experiments were conducted in Ohio, U.S.A.
• 2 Stress volatile attractiveness was first assessed by positioning traps baited with acetaldehyde, acetone, ethanol and methanol in ornamental nurseries. Cumulative trap counts confirmed that ethanol was the most attractive stress‐related volatile to X. germanus. Methanol‐baited traps were slightly attractive to X. germanus, whereas traps baited with acetaldehyde and acetone were not attractive to any ambrosia beetle.
• 3 A series of tree injection experiments were also conducted to determine the ability of these volatiles to induce attacks by ambrosia beetles under field conditions. Injection of ethanol into Magnolia virginiana induced the largest number of attacks, whereas injection of acetaldehyde induced more attacks than methanol or acetone. Xylosandrus germanus was the most predominant species emerging from M. virginiana injected with each of the stress‐related volatiles. No attacks by wood‐boring beetles were observed on water injected or uninjected control trees.
• 4 Solid‐phase microextraction–gas chromatography–mass spectrometry confirmed the emission of acetaldehyde, acetone, ethanol and methanol after their injection into M. virginiana.
• 5 Xylosandrus germanus has an efficient olfactory‐based mechanism for differentiating among host volatile cues. Injecting select trees with stress‐related volatiles, particularly ethanol, shows promise as a trap tree strategy for X. germanus and other ambrosia beetles.

     

Latitude,elevation and the tempo of molecular evolution in mammals

Faster rates of microevolution have been recorded for plants and marine foraminifera occupying warmer low latitude environments relative to those occurring at higher latitudes. By contrast, because this rate heterogeneity has been attributed to a relationship between thermal habit and mutagenesis via a body temperature linkage, it has been assumed that microevolution in mammals should not also vary systematically with environmental temperature. However, this assumption has not previously been empirically examined. In this study, we tested for a thermally mediated influence on the tempo of microevolution among mammals using a comprehensive global dataset that included 260 mammal species, from 10 orders and 29 families. In contrast to theoretical predictions, we found that substitution rates in the cytochrome b gene have been substantially faster for species living in warmer latitudes and elevations relative to sister species living in cooler habitats. These results could not be attributed to factors otherwise thought to influence rates of microevolution, such as body mass differentials or genetic drift. Instead, the results indicate that the tempo of microevolution among mammals is either responding directly to the thermal environment or indirectly via an ecological mechanism such as the ‘Red Queen’ effect.     

Primate origins and the evolution of angiosperms

Traditionally, the morphological traits of primates were assumed to be adaptations to an arboreal way of life. However, Cartmill [1972] pointed out that a number of morphological traits characteristic of primates are not found in many other arboreal mammals. He contends that orbital convergence and grasping extremities indicate that the initial divergence of primates involved visual predation on insects in the lower canopy and undergrowth of the tropical forest. However, recent research on nocturnal primates does not support the visually-oriented predation theory. Although insects were most likely important components of the diets of the earliest euprimates, it is argued here that visual predation was not the major impetus for the evolution of the adaptive traits of primates. Recent paleobotanical research has yielded evidence that a major evolutionary event occurred during the Eocene, involving the angiosperms and their dispersal agents. As a result of long-term diffuse coevolutionary interactions with flowering plants, modern primates, bats, and plant-feeding birds all first arose around the Paleocene-Eocene boundary and became the major seed dispersers of modern tropical flora during the Eocene. Thus, it is suggested here that the multitude of resources available on the terminal branches of the newly evolved angiosperm, rain forest trees led to the morphological adaptations of primates of modern aspect.     

四川南充市郊瓢虫物种多样性的初步研究

20 0 3年3月～2 0 0 4年5月,分别在南充市郊的人工林、农田、河漫滩草丛、灌木丛4种生境进行瓢虫种群结构及多样性的抽样调查研究,共采集瓢虫标本1 2 1 6只,经鉴定隶属7亚科,2 2属,3 6种。个体数量以瓢虫亚科最多,食植瓢虫亚科次之。物种数以瓢虫亚科最多,食植亚科次之,小艳瓢虫亚科最少。各生境的多样性指数和物种丰富度排序为灌木丛>河漫滩草丛>人工林>农田。     

Parallel habitat-driven differences in the phylogeographical structure of two independent lineages of Mediterranean saline water beetles

It has been hypothesized that species living in small lentic water bodies, because of the short-term geological persistence of their habitat, should show higher dispersal ability, with increased gene flow among populations and a less pronounced phylogeographical structure. Conversely, lotic species, living in more geologically stable habitats, should show reduced dispersal and an increased phylogeographical structure at the same geographical scales. In this work we tested the influence of habitat type in two groups of aquatic Coleoptera ( Nebrioporus ceresyi and Ochthebius notabilis groups, families Dytiscidae and Hydraenidae respectively), each of them with closely related species typical of lotic and lentic saline Western Mediterranean water bodies. We used mitochondrial cox1 sequence data of 453 specimens of 77 populations through the range of nine species to compare a lotic vs. a lentic lineage in each of the two groups. Despite the differences in biology (predators vs. detritivorous) and evolutionary history, in both lotic lineages there was a higher proportion of nucleotide diversity among than within groups of populations, and a faster rate of accumulation of haplotype diversity (as measured by rarefaction curves) than in the lentic lineages. Similarly, lotic lineages had a higher absolute phylogenetic diversity, more remarkable considering their smaller absolute geographical ranges. By comparing closely related species, we were able to show the effect of contrasting habitat preferences in two different groups, in agreement with predictions derived from habitat stability.     

Checklist of beetles (Coleoptera) of Canada and Alaska. Second edition

All 8237 species-group taxa of Coleoptera known to occur in Canada and Alaska are recorded by province/territory or state, along with their author(s) and year of publication, in a classification framework. Only presence of taxa in each Canadian province or territory and Alaska is noted. Labrador is considered a distinct geographical entity. Adventive and Holarctic species-group taxa are indicated. References to pertinent identification keys are given under the corresponding supraspecific taxa in the data archive.     

Desiccation resistance and water balance in southern African keratin beetles (Coleoptera, Trogidae): the influence of body size and habitat

Desiccation resistance and water balance were examined in the adults of seven trogid species, which differed both in body size and in the habitats from which they were collected. Body water contents (51–58% fresh mass) and desiccation rates at 27 °C (0.00026–0.00093 g h⁻¹) in these species were very similar to those of unrelated, similar-sized beetles from arid habitats. The keratin beetles differed markedly from many other adult Coleoptera by virtue of their very high haemolymph osmolality and inability to regulate haemolymph osmolality, and to catabolise lipids for water production, during desiccation. Like most other insects, the xeric trogid species had lower rates of water loss and longer survival times than trogids from mesic areas. This was due both to lower rates of water loss and to the larger body size of species from the more arid areas. Because absolute body water content was higher in large beetles than in small ones, larger body size conferred higher desiccation resistance on the very large Kalahari desert species. This suggests that there may be strong selection for large body size in such insects from arid areas. Most ecological and ecophysiological investigations of geographical variation in body size, and the species-body size distribution, have focused on temperature and metabolic rate as explanatory variables. This study suggests that attention should also be given to desiccation resistance. Accepted: 29 September 1997     

The gut of Guatemalan passalid beetles: a habitat colonized by cellobiose- and xylose-fermenting yeasts

The gut of insects is a productive environment for discovering undescribed species of yeasts, and the gut of wood-feeding insects of several families is especially rich in yeasts that carry out the fermentation of cellobiose and xylose. Passalid beetles (Passalidae, Coleoptera) live in dead wood that they ingest as their primary food source. We report the isolation, molecular identification and physiological characterization of 771 yeast cultures isolated from the gut of 16 species of passalids collected in nine localities in Guatemala. Ascomycete yeasts were present in the gut of every passalid studied, and the xylose-fermenting (X-F) yeasts Scheffersomyces shehatae and Scheffersomyces stipitis were the most abundant taxa isolated. The gut of the beetles also contained undescribed cellobiose-fermenting and X-F species in the Lodderomyces, Scheffersomyces and Spathaspora, and undescribed species in Sugiyamaella clades as well as rare yeast species in the Phaffomyces and Spencermartinsiella clades. Basidiomycete yeasts in the genera Cryptococcus and Trichosporon were also common. The yeast species richness was influenced by the host species and the substrate, and gut-inhabiting yeasts have the ability to survive the differing physiological conditions of several gut compartments.     

Traits,trees and taxa: global dimensions of biodiversity in mammals

Measures of biodiversity encompass variation along several dimensions such as species richness (SR), phylogenetic diversity (PD) and functional/trait diversity (TD). At the global scale, it is widely recognized that SR and PD are strongly correlated, but the extent to which either tends to capture variation in TD is unclear. Here, we assess relationships among PD, SR and TD for a number of traits both across clades and regional assemblages of mammals. We also contrast results using two different measures of TD, trait variance and a new measure we refer to as trait bin filling (the number of orders of magnitude of variation that contain at least one species). When TD is defined as trait variance, PD is a much stronger correlate of TD than SR across clades, consistent with hypotheses about the conservation value of PD. However, when TD is defined as bin filling, PD and SR show similar correlations with TD across clades and space. We also investigate potential losses of SR, PD and TD if species that are currently threatened were to go extinct, and find that threatened PD is often a similar predictor of threatened TD as SR.     

Chromosome evolution in ground beetles: localization of the rDNA loci in the tribe Harpalini (Coleoptera,Carabidae)

The pattern of localization of the ribosomal genes was studied by means of fluorescence in situ hybridization in 39 species of the tribe Harpalini. Most of them show one pair of autosomes carrying the ribosomal genes in a distal position of a single chromosome arm. This pattern is hypothesized to be ancestral for the whole tribe. Both, chromosome number and the number and localization of rDNA loci, show little variation and are therefore of little phylogenetic value. Only in the subtribe Ditomina is there enough variation to characterize phyletic relationships. The stability of rDNA loci is even higher than the constancy of chromosome number, as most species of Ditomina (genera Dixus, Eocarterus, Carterus, Odontocarus and Ditomus) have the usual pair of autosomes with rDNA loci, in spite of remarkable differences in the diploid number. Only Dixus sphaerocephalus and Dixus clypeatus have two autosomal pairs with a fluorescent signal. These results do not support the hypothesis that the high chromosome numbers found within Ditomina are the result of polyploid change from the ancestral 2n = 37 karyotype of the tribe Harpalini. Chromosomal translocations or the presence of mobile genetic elements are plausible sources of the few cases of intraspecific polymorphism in the rDNA loci found in species of Harpalus.     

Data on molecular taxonomy and genetic diversification of the European Hermit beetles, a species complex of endangered insects (Coleoptera: Scarabaeidae, Cetoniinae, Osmoderma)

A molecular analysis was carried out on the European hermit beetles (the Osmoderma eremita species complex) to explore their genetic diversification and the robustness of previous morphologically based taxonomic arrangements. Complete sequences of mtDNA cytochrome C oxidase I gene were obtained from 26 individuals. Mean levels of interspecific sequence divergence ranged from 0.044 to 0.186. The results indicate a clear-cut distinction between two clades. The first one includes the W-European O. eremita Scopoli 1763 ; and the two Italian endemic taxa Osmoderma italicum Sparacio, 2000 and Osmoderma cristinae Sparacio, 1994 ; from southern peninsular Italy and Sicily, respectively. The second one includes the widespread E-European Osmoderma barnabita ; and the southern Balcanic Osmoderma lassallei Baraud and Tauzin, 1991 from Greece and European Turkey. Within the two clades, molecular and morphological data well support a specific rank for O. lassallei and O. barnabita on one side, and for O. eremita and O. cristinae on the other side, while the taxonomic position of O. italicum , more closely related to O. eremita , is still uncertain. Current geographical distribution, interspecific genetic diversification, and very low levels of intraspecific genetic divergence in western European populations of O. eremita sensu stricto are hypothesized to be the result of multiple speciation events (mainly occurred in refugial forest areas of the Italian and Balkan peninsulas and Sicily before and during the Pleistocene glacial peaks), followed by fast post-glacial northward and westward expansion of some species.     

Species status and population genetic structure of the flightless chafer beetles Prodontria modesta and P. bicolorata (Coleoptera; Scarabaeidae) from South Island, New Zealand

This study uses isozyme electrophoresis to investigate the systematic status of two rare flightless chafer beetle species, Prodontria modesta and P. bicolorata , currently distinguished solely on the basis of colour. Seven polymorphic loci were analysed for the species in sympatry and allopatry. In sympatry, gene frequencies imply no genetic barrier between the two colour forms. Wright's hierarchical F-statistics were calculated to determine how the genetic variation is partitioned across the geographic range of the two species. Strong geographic structuring occurs at the population level but there is little genetic differentiation attributable to species. Comparisons of morphological measurements are in support of the electrophoretic results. The systematic significance of the two distinct colour forms is thus questionable. Under the biological, recognition or phylogenetic species concepts, the genetic data suggest that there is only one species, polytypic for a colour pattern. Most of the genetic diversity of this group of beetles lies within and among populations, which differ quite markedly over their geographic range, rather than between the two named species.