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.

     

MusselMytilus edulis (Mytilacea) dynamics in relation to environmental gradients and intraspecific interactions

The spatial variations in the densities of adult (>1 year old) musselsMytilus edulis L. in the Exe estuary, South-west England, are investigated in relation to six potentially significant environmental gradients; distance up-estuary and up-shore, substrate softness, mussel bed topography, bed area and proportion covered by algae. The most important correlate of mussel density was the up-shore gradient, as measured by exposure time; mussels were densest just below mid-tide level. The level of recruitment of spat mussels (O yr) to each bed depended on the densities of adults already present; more spat were recruited where adults were denser. Their subsequent mortality was strongly density dependent, with the numbers surviving the winter also being related to the density of adults. Hence the population as a whole was self-sustaining and densities on the individual beds were related to the up-shore gradient of exposure time. The question of how adult densities became established in the first place is therefore discussed. In former times, fishermen laid many mussel beds over the estuary and it is concluded that, once abandoned, only those placed at or below the mid-tide level survived.     

Niche breadth and resource partitioning by four sympatric species of bark beetles (Coleoptera: Scolytidae)

Summary In a North Carolina population of Diamorpha smallii, densities were artificially manipulated by thinning stands to predetermined densities. Individuals in areas of high density produce fewer seeds than individuals at low density in the same habitat. Three components of fecundity, the number of flowers per plant, the number of fruits per plant, and the number of seeds per fruit, were negatively correlated with density. The relationship of components of fecundity to density were used to develop a model of population regulation for this species. These results and predictions from the model are discussed in relation to other density studies.     

Spatial and temporal segregation in dung beetles (Coleoptera: Scarabaeinae) in the Cerrado of Central Brazil

Biodiversity and Conservation - In dung beetles, spatial and temporal segregation is determined by the niche and evolutionary history of the species and is mediated by competition. Different...     

New mesozoic Ithyceridae beetles (Coleoptera)

A new subfamily, Mongolocarinae subfam. nov. of the family Ithyceridae, from the Middle-Upper Jurassic and Lower Cretaceous of Asia is described. It includes five genera with five species: Palaeocar gen. nov. (with P. princeps sp. nov.), Mongolocar gen. nov. (M. orcinus sp. nov.), Praecar gen. nov. (P. stolidus sp. nov.), Karacar gen. nov. (M. contractus sp. nov.), and Baissacar gen. nov. (B. passarius sp. nov.).     

Environmental gradients and succession patterns of carabid beetles (Coleoptera: Carabidae) in an Alpine glacier retreat zone

Accelerated by global warming, retreating glaciers leave behind spatially ordered moraines with underlying primary succession and disturbance. Current knowledge of primary succession comes mainly from studies of vegetation dynamics. Information about above-ground macroinvertebrates is still scarce. We used carabid beetles (Coleoptera; Carabidae) as indicator taxon to assess the effects of (1) terrain age (species turnover along the proglacial chronosequence) and (2) small-scale habitat architecture (vegetation cover, surface texture) on the carabid assembly. For this purpose, 33 sampling sites with pitfall traps were installed throughout the glacier foreland Morteratsch (Engadine, Switzerland), adjacent sparse forests serving as reference sites. With a total of 33 carabid species on the foreland and another 2 on the reference sites, the study area yielded a very high carabid species diversity compared to other glacier forelands. In general, the age of deglaciation proved to be a highly significant predictor for the carabid distribution, especially for particularly discriminant species. Observed species richness and activity densities showed bimodal patterns with a steep increase within the first ca. 40?years, a decline between around 40–90?years, and a further increase towards the terminal moraine. There was no evidence of dispersal-stochasticity: distinct clusters of sites with similar species composition were found. Microhabitat suitability proved to be a secondary effect, embedded in a temporal framework of primary succession. Surface cover with litter, herbs and dwarf-shrubs turned out to be the crucial habitat factors. Habitat loss as a result of climate warming will primarily affect cold-stenotopic carabids, but may potentially be absorbed by active selection for cooler microhabitats.     

Habitat selection and grouping of beetles (Coleoptera)

Beetles were collected by pitfall trapping for a two-year period in seven adjacent habitats in an upland site in North Wales. Positive correlations were demonstrated between number of beetle species and number and diversity of plant species. Similar correlations were shown between beetle numbers and plant species. However, only 15% of the beetle species were herbivores requiring host plants. The degree of habitat selection by individual beetle species was demonstrated, ranging from habitat specialist, being found in one habitat, lo habitat generalist, being found in most habitats. Herbivores were significantly more habitat specialist than predators or scavengers. The grouping of beetles, demonstrated by ordination analysis, was similar to, but less precise than, the grouping of plant species. The beetle groups reflect habitat selection preferences by individual species rather than a functional relationship between beetle species. They provide an example of the centrifugal structure of habitat selection theory.     

Monophyly of terrestrial adephagan beetles as indicated by three nuclear genes (Coleoptera: Carabidae and Trachypachidae)

The beetle suborder Adephaga is traditionally divided into two sections on the basis of habitat, terrestrial Geadephaga and aquatic Hydradephaga. Monophyly of both groups is uncertain, and the relationship of the two groups has implications for inferring habitat transitions within Adephaga. Here we examine phylogenetic relationships of these groups using evidence provided by DNA sequences from all four suborders of beetles, including 60 species of Adephaga, 4 Archostemata, 3 Myxophaga, and 10 Polyphaga. We studied 18S ribosomal DNA and 28S ribosomal DNA, aligned with consideration of secondary structure, as well as the nuclear protein-coding gene wingless . Independent and combined Bayesian, likelihood, and parsimony analyses of all three genes supported placement of Trachypachidae in a monophyletic Geadephaga, although for analyses of 28S rDNA and some parsimony analyses only if Coleoptera is constrained to be monophyletic. Most analyses showed limited support for the monophyly of Hydradephaga. Outside of Adephaga, there is support from the ribosomal genes for a sister group relationship between Adephaga and Polyphaga. Within the small number of sampled Polyphaga, analyses of 18S rDNA, wingless , and the combined matrix supports monophyly of Polyphaga exclusive of Scirtoidea. Unconstrained analyses of the evolution of habitat suggest that Adephaga was ancestrally aquatic with one transition to terrestrial. However, in analyses constrained to disallow changes from aquatic to terrestrial habitat, the phylogenies imply two origins of aquatic habit within Adephaga.     

Righting kinematics in beetles (Insecta: Coleoptera)

Twenty modes of stereotyped righting motions were observed in 116 representative species of coleoptera. Methods included cine and stereocine recording with further frame by frame analysis, stereogrammetry, inverse kinematic reconstruction of joint angles, stroboscopic photography, recording of electromyograms, 3D measurements of the articulations, etc. The basic mode consists of a search phase, ending up with grasping the substrate, and a righting, overturning phase. Leg coordination within the search cycle differs from the walking cycle with respect to phasing of certain muscle groups. Search movements of all legs appear chaotic, but the tendency to move in antiphase is still present in adjacent ipsilateral and contralateral leg pairs. The system of leg coordination might be split: legs of one side might search, while contralateral legs walk, or fore and middle legs walk while hind legs search. Elaborated types of righting include somersaults with the aid of contralateral or diagonal legs, pitch on elytra, jumps with previous energy storage with the aid of unbending between thoracic segments (well-known for Elateridae), or quick folding of elytra (originally described in Histeridae). Righting in beetles is compared with righting modes known in locusts and cockroaches. Search in a righting beetle is directed dorsad, while a walking insect searches for the ground downwards. Main righting modes were schematized for possible application to robotics.     

Breeding bird diversity in relation to environmental gradients in China

Geographic variation in species richness has been explained by different theories such as energy, productivity, energy–water balance, habitat heterogeneity, and freezing tolerance. This study determines which of these theories best account for gradients of breeding bird richness in China. In addition, we develop a best-fit model to account for the relationship between breeding bird richness and environment in China. Breeding bird species richness in 207 localities (3271 km² per locality on average) from across China was related to thirteen environmental variables after accounting for sampling area. The Akaike's information criterion (AIC) was used to evaluate model performance. We used Moran's I to determine the magnitude of spatial autocorrelation in model residuals, and used simultaneous autoregressive model to determine coefficients of determination and AIC of explanatory variables after accounting for residual spatial autocorrelation. Of all environmental variables examined, normalized difference vegetation index, a measure of plant productivity, is the best variable to explain the variance in breeding bird richness. We found that species richness of breeding birds at the scale examined is best predicted by a combination of plant productivity, elevation range, seasonal variation in potential evapotranspiration, and mean annual temperature. These variables explained 47.3% of the variance in breeding bird richness after accounting for sampling area; most of the explained variance in richness is attributable to the first two of the four variables.     

Global diversity of water beetles (Coleoptera) in freshwater

The global diversity of True Water Beetles, False Water Beetles and Phytophilous Water Beetles (sensu Jäch, 1998a. In Jäch &; Ji (eds), Water Beetles of China, Vol. II. Zoologisch-Botanische Gesellschaft in Österreich and Wiener Coleopterologenverein, Wien: 25–42.) is assessed. Facultative Water Beetles, Parasitic Water Beetles and Shore Beetles (sensu Jäch, 1998a. In Jäch &; Ji (eds), Water Beetles of China, Vol. II. Zoologisch-Botanische Gesellschaft in Österreich and Wiener Coleopterologenverein, Wien: 25–42.) are here classified as “paraquatic” and are thus not included in the assessment. It is estimated that about 18,000 species of aquatic Coleoptera are roaming the earth at present. About 12,600 (70%) of these are already described (deadline: October 2005). About 30 beetle families have aquatic representatives, and in 25 of these families at least 50% of the species are to be considered as aquatic. Six families are supposed to include 1,000 or more aquatic species: Dytiscidae (3,908 described species/5,000 estimated), Hydraenidae (1,380/2,500), Hydrophilidae (1,800/2,320), Elmidae (1,330/1,850), Scirtidae (900/1,700) and Gyrinidae (750/1,000). Scirtidae and Hydraenidae are regarded as the least explored families, the number of described species in each of these two families probably will be almost doubled in the future. The Palearctic (ca. 3,350 described species/ca. 3,900 estimated), the Neotropical (2,510/3,900) and the Afrotropical Region (2,700/3,750) harbour almost the same number of water beetle species, followed by the Oriental (2,200/3,580) and the Australian/Pacific Realm (1,340/2,100). The Nearctic (1,420/1,550) is by far the poorest region in terms of water beetle diversity.     

Phenetic and cladistic relationships among tenebrionid beetles (Coleoptera)

Abstract. The higher classification of Tenebrionidae is analysed using numerical phenetic, numerical cladistic and traditional Hennigian methods. In all, eighty characters are examined for about 335 taxa; definitive analyses are made on combinations of eighteen to seventy characters for thirty-three OTUs. At lower levels of relationship (genera and closely related tribes) phenetic and cladistic classifications are shown to be congruent, but at higher levels (tribes and subfamilies) there is marked discordance with phenetic results being more stable. A consensus classification is more similar to the Hennigian cladogram than is any single computer generated cladogram. Two main tribal groups – the Lagrioid and Tenebrionoid groups – are suggested which differ in defensive glands, female anatomy, wing and mouthpart morphology, larval characters and other features. The Tenebrionoid group consists of three main subdivisions – the tenebrionine, coelometopine and diaperine lineages. Changes in classificatory position are recommended for eighty-seven genera and tribes (listed in Appendix E) and implied for numerous others.     

Patterns in the distribution, abundance and body size of carabid beetles (Coleoptera: Caraboidea) in relation to dispersal ability

The effects of dispersal ability, measured as two wing size categories (brachypterous vs. macropterous), on the distribution, abundance and body size, and on the relationships between these variables were examined in eighty-four species of carabid beetles over twenty-two sites in the northern Iberian peninsula. Geographic ranges of species (restricted to the northern Iberian peninsula vs. widespread—European or wider range) were also taken into account in the analyses because macropterous species significantly tended to exhibit wider geographic ranges than did brachypterous species. Regional distributions were wider in brachypterous-restricted and brachypterous-widespread species than in macropterous-widespread species. The three groups did not differ in abundance. Differences in regional distributions between groups may be explained by referring to a trade-off between dispersal ability and establishment ability indicated in the literature. Macropterous species would occupy relatively few sites due to a high frequency of unsuccessful colonizations. The relationships between regional distribution and abundance were positive for all the three groups, brachypterous-restricted, brachypterous-widespread and macropterous-widespread species. The regression line for the last group showed a lower elevation than those for brachypterous-restricted and brachypterous-widespread species. This fact was probably due to differences in regional distributions between groups. No relationship between abundance and body size was significant. Regressions of regional distribution on body size were positive in brachypterous-restricted and brachypterous-widespread carabids, but the relationship was not significant in macropterous-widespread carabids. These results were interpreted in terms of differences in body size–dependency of travelling velocities between flying and running carabids.     

Susceptibility of lady beetles (Coleoptera: Coccinellidae) to entomopathogenic nematodes

We investigated differential susceptibility of lady beetles to entomopathogenic nematodes, for two reasons: (1) to estimate potential nontarget effects on natural lady beetle populations, (2) to compare the susceptibility of exotic versus native lady beetle species. We hypothesize that successful establishment of some exotically introduced arthropods may be due, in part, to a lower susceptibility relative to competing native species. In laboratory studies, we compared the pathogenicity, virulence, and reproductive capacity of Heterorhabditis bacteriophora and Steinernema carpocapsae among two native (Coleomegilla maculata and Olla v-nigrum) and two successfully established exotic (Harmonia axyridis and Coccinella septempunctata) lady beetles, and a known susceptible lepidopteran host, Agrotis ipsilon. After 1 and 2 days of exposure to either nematode species, mortality of A. ipsilon was higher than in all lady beetles. Thus, we predict that nematode field applications would have significantly less impact on lady beetle populations than on a susceptible target pest. Additionally, the impact of soil-applied nematodes may be lower on lady beetles than on soil-dwelling hosts because the former spends relatively less time on the soil. Exotic lady beetles were less susceptible to nematode infection than native species. Reproductive capacity data also indicated lower host suitability in H. axyridis, but not in C. septempunctata. Overall, the hypothesis that low susceptibility to pathogens in certain exotic lady beetles may have contributed to competitive establishment was supported (especially for H. axyridis). Additional studies incorporating different hosts and pathogens from various geographic locations will be required to further address the hypothesis.     

Anthophagy in the leaf beetles (Coleoptera,Chrysomelidae)

Laboratory experiments were performed on leaf beetles collected on flowers. Flower consumption (anthophagy) was demonstrated for adults of Donacia bicolora, D. brevitarsis, D. obscura, D. thalassina, Plateumaris discolor, Cryptocephalus laetus, C. sericeus, C. solivagus, Labidostomis longimana, Hydrothassa marginella, Phaedon concinnus, Galerucella nymphaeae, Neocrepidodera femorata, Altica oleracea, Aphthona lutescens, Longitarsus pellucidus, and larvae of Entomoscelis adonidis, H. marginella, and G. nymphaeae for the first time for all the species except for P. discolor, L. longimana, and C. sericeus. The feeding behavior was described, and the mouthparts of adults were studied. The mandibles and maxillae of the Donacia, Plateumaris, and Orsodacne species mentioned are adapted to consuming pollen. Some questions of ecology and evolution of anthophagy are discussed. An overview of literature on anthophagy in the leaf beetles is presented.     

First records of hindwings of Permian beetles (Coleoptera)

Three isolated hindwings of beetles are described from the locality of Isady, late Middle Permian of northern European Russia. The wings share all main features characteristic of beetles and combine plesiomorphic and apomorphic states of characters found in different suborders. The wings most probably belonged to beetles of the families Asiocoleidae and/or Taldycupedidae.     

Feeding behavior of leaf beetles (Coleoptera,Chrysomelidae)

The feeding behavior of adult leaf beetles (41 species from 18 genera and 8 subfamilies) was studied for the first time. Beetles of the genera Chrysolina, Chrysomela, Cryptocephalus, Galeruca, Gastrophysa, Labidostomis, Leptinotarsa, Timarcha, and Cassida stigmatica gnaw a leaf from the edge, whereas the representatives of Donacia, Galerucella, Lema, Lilioceris, Oulema, Phyllobrotica, Plagiodera, Zeugophora, Hypocassida, and most species of Cassida gnaw the leaf plane. In addition, adults of Lilioceris merdigera and Donacia clavipes feed on young leaves rolled into a tube. New host plants are reported for the first time: Hyoscyamus niger for the larvae of the Colorado potato beetle and Naumburgia thyrsiflora for Galerucella grisescens.     

Biogeography of the phoracanthine beetles (Coleoptera: Cerambycidae)

Six biogeographic subregions of the phoracanthine beetles are proposed on the basis of 136 valid species in all eleven genera of this Australasian group of insects: the Kosciuskan, Western, Eyrean, Torresian, Timorian and New Guinean. Both phenetic and cladistic approaches are employed in the biogeographic study of these beetles. Phenetically, the Kosciuskan and Torresian fauna are the most similar and the least faunal similarity occurs between the New Guinean subregion and all others. Cladistically, two distinct peripheral faunas are divided: the southern Western+Kosciuskan and the northern New Guinean+Torresian+Timorian. The Eyrean fauna in the central Australian continent is more distantly related to the remainder than the latter are to each other. Biogeographic history of the phoracanthine beetles is discussed extensively.     

Ground beetles of the Ukraine (Coleoptera, Carabidae)

A review of the ground beetles of the Ukrainian fauna is given. Almost 750 species from 117 genera of Carabidae are known to occur in the Ukraine. Approximately 450 species of ground beetles are registered in the Carpathian region. No less than 300 species of ground beetles are found in the forest zone. Approximately 400 species of Carabidae present in the forest-steppe zone are relatively similar in species composition to those in the forest territories. Some 450 species of Carabidae are inhabitants of the steppe zone. Representatives of many other regions of heterogeneous biotopes such as forest, semi desert, intrazonal, etc. can be found in the steppe areas. The fauna of Carabidae (ca. 100 species) of the lowlands of southern Ukraine (sandy biotopes), situated mostly in the Kherson region, is very peculiar. The fauna of the Crimean mountains contains about 300 species. Conservation measures for the Carabidae are discussed.     

Susceptibility of last instar red flour beetles and confused flour beetles (Coleoptera: Tenebrionidae) to hydroprene.

Last instar larvae of the red flour beetle, Tribolium castaneum (Herbst), and the confused flour beetle, Tribolium confusum Jacquelin du Val, were either exposed for 8-144 h on concrete treated with 1.9 x 10(-3) mg(AI)/per cm2 hydroprene, or continually exposed on concrete treated with 9.8 x 10(-4) to 1.9 x 10(-3) mg[AI]/per cm2 hydroprene. In both tests, larvae were exposed and held at 27 or 32 degrees C and 40, 57, or 75% RH. When larvae were exposed with no food to hydroprene for different time intervals, then transferred to untreated concrete containing flour, consistent effects were produced only at 144 h. At this exposure interval, the percentage of beetles arrested in the larval stage after 3-4 wk was generally greater at 75% RH compared with 40 and 57% RH, but there were no differences between species or temperature. The percentages of dead adult red flour beetles and live adults with morphological deformities were also greatest at 75% RH, and defects were more prevalent in red flour beetles than in confused flour beetles. When larvae were continually exposed to different concentrations of hydroprene on concrete that contained flour, the percentage of arrested larvae, dead adults, and live adults of both species generally increased with concentration. There were more deleterious effects at 75% RH compared with either 40 or 57% RH, and effects were more pronounced in the red flour beetle compared with the confused flour beetle. In both experiments, temperature effects were variable and inconclusive. Results indicate that continual exposure of last instar red flour beetle and confused flour beetle to hydroprene can limit population development, but exposure intervals of >6 d may be required for maximum effectiveness.