Endemism patterns in the Italian leaf beetle fauna (Coleoptera,Chrysomelidae)

In this contribution the results of a zoogeographical analysis, carried out on the 123 endemic leaf beetle species (Coleoptera: Chrysomelidae) occurring in Italy and its immediately adjacent regions, are reported. To assess the level of faunistic similarity among the different geographic regions studied, a cluster analysis was performed, based on the endemic component. This was done by calculating the Baroni Urbani & Buser’s similarity index (BUB). Finally, a parsimony analysis of endemicity (PAE) was used to identify the most important areas of endemism in Italy.     

广聚萤叶甲成虫取食经历对后续 产卵寄主选择的影响

【背景】取食经历对植食性昆虫的寄主选择行为具有较大影响,影响天敌昆虫寄主专一性测定的设计和结果解释。【方法】采用选择性试验,观察了入侵豚草的重要天敌——广聚萤叶甲成虫羽化后取食不同植物对其后续产卵寄主选择的影响。【结果】与取食豚草的试虫相比,有取食三裂叶豚草、苍耳或菊芋经历的成虫选择苍耳产卵的频次增加,不再对豚草表现出明显的选择偏好性。对产卵识别期的Cox模型分析结果表明,成虫早期取食不同植物,对后续产卵选择有显著影响,成虫羽化后如果先取食豚草或三裂叶豚草,则选择苍耳产卵的倾向显著低于豚草;但如果先取食苍耳、菊芋和农家向日葵,则选择苍耳产卵的倾向与豚草无显著差异。【结论与意义】由此推测,广聚萤叶甲初羽化成虫取食的植物对其后续产卵选择具有较大影响,因而在寄主专一性测定中应关注测试前饲喂的植物种类。     

Characterization and chromosome location of satellite DNA in the leaf beetle Chrysolina americana (Coleoptera, Chrysomelidae)

This paper is the first record of the satellite DNA of the specialized phytophagous genus Chrysolina. The satellite DNA of Chrysolina americana is organized in a tandem repeat of monomers 189 bp long, has a A + T content of 59.6 % and presents direct and inverted internal repeats. Restriction analysis of the total DNA with methylation sensitive enzymes suggests that this repetitive DNA is undermethylated. In situ hybridization with a biotinylated probe of the satellite DNA showed the pericentromeric localization of these sequences in all meiotic bivalents. The presence of this repetitive DNA in other species of the genus was also tested by Southern analysis. The results showed that this satellite DNA sequence is specific to the C. americana genome and has not been found in three other species of Chrysolina with a different choice of host plants than in the former. This revised version was published online in July 2006 with corrections to the Cover Date.     

Adaptation to a new host plant, Centrosema pubescens (Fabales: Leguminosae), by the phytophagous ladybird beetle, Epilachna vigintioctopunctata (Coleoptera: Coccinellidae), in tropical Asia

The host suitability of Centrosema pubescens (Leguminosae) was evaluated within two sympatric populations feeding on Solanum plants (Solanaceae) and C. pubescens in Epilachna vigintioctopunctata in Malaysia (Kuala Lumpur) and Indonesia (Bogor and Padang). In the Bogor and Padang populations, Centrosema strains had a significantly higher emergence rate than sympatric Solanum strains. In Kuala Lumpur, there was no significant difference in emergence rates between the two strains. When Centrosema strains from Kuala Lumpur and Padang were reared and maintained solely on Solanum plants, the emergence rate on C. pubescens gradually decreased with successive rearing generation and resulted in 0% in the 7th or 20th generations. These findings suggest that the current host suitability of C. pubescens depends on the previous experience of each population with the use of this plant as a host. However, we were not able to demonstrate from laboratory selection that Solanum strains increase the host adaptation to C. pubescens because every Solanum strain became extinct in the third generation when reared solely on C. pubescens. Received: August 16, 1999 / Accepted: June 5, 2000     

Spatial distribution of the cereal leaf beetle (Coleoptera: Chrysomelidae) in wheat

A 2-yr study was conducted in wheat fields in South Carolina involving weekly sampling of cereal leaf beetle, Oulema melanopus (L.). In each of the six fields of this study, temporal patterns showed two distinct peaks in March and in May of adult O. melanopus. Populations decreased as wheat plants matured. In 2009, larval populations had one peak in April in between the two adult peaks. The χ(2) statistics for observed and Poisson predicted distributions of O. melanopus indicated nonrandom distribution for adults and larvae. In addition, the values of I(D) were >1 for adults and larvae in both years across sampling dates. These results indicate that the sampling distributions of both adult and larval populations of O. melanopus were aggregated. Slopes of Taylor power's law (b) and patchiness regressions (β) were significantly (P < 0.05) different than one in all cases, except for b in 2008 for adults. Across sampling dates, the distance from field border had a significant effect on adult O. melanopus in both years, but not on larval O. melanopus. Densities of adult O. melanopus were greatest at 0 m (the field edge), and decreased at 5-25 m from the field edge. The inverted distance weighted interpolation method showed considerable levels of spatial variability in densities within fields. High densities along the edge of wheat fields suggests that localized control methods in wheat may be effective in reducing migration of O. melanopus and damage in corn, Zea mays L.     

Host location in Oomyzus gallerucae (Hymenoptera: Eulophidae), an egg parasitoid of the elm leaf beetle Xanthogaleruca luteola (Coleoptera: Chrysomelidae)

Eggs of the elm leaf beetle Xanthogaleruca luteola are often heavily attacked by the chalcidoid wasp Oomyzus gallerucae. We studied the chemical signals mediating interactions between the egg parasitoid, its host, and the plant Ulmus campestris. Olfactometer bioassays with O. gallerucae showed that volatiles of the host-plant complex attract the parasitoid. In order to determine the source of attractive volatiles within this host-plant-complex, we tested separately the effect of odours of eggs, gravid elm leaf beetle females, faeces of the beetles and elm twigs (with undamaged leaves and leaves damaged either mechanically or by feeding of the beetles). Odours of faeces of the elm leaf beetle were attractive, whereas neither volatiles from eggs nor from gravid females acted as attractants. Volatiles from undamaged or damaged plants did not elicit a positive reaction in O. gallerucae, whereas volatiles from feeding-damaged plants onto which host eggs had been deposited were attractive. This latter result suggests that it is not feeding but deposition of host eggs onto elm leaves that induces the production of plant volatiles attractive to the egg parasitoid. Investigations of the search patterns of O. gallerucae within the habitat by laboratory bioassays revealed that the egg parasitoid encounters host eggs by chance. Contact kairomones from faeces were demonstrated to be important in microhabitat acceptance, while contact kairomones isolated from the host eggs are relevant for host recognition. Received: 12 February 1997 / Accepted: 29 April 1997     

Mating behavior and genital damage during copulation in the leaf beetle Lema coronata (Chrysomelidae: Criocerinae)

The criocerine leaf beetle Lema coronata Baly has extremely long genitalia that reach more than twice the body length in both sexes. We observed mating behavior of this species in the laboratory and inspected the male genital morphology using a scanning electron microscope. The males did not perform pre-copulatory courtship and post-copulatory guarding of the mates, and copulation lasted only for about 30 min. The surface of male genitalia is smooth without any special structures at the tip. A fragment of broken male genitalia was detected in the spermathecal duct of one female. We discuss the adaptive significance of male genital damage and the selective factor of elongated genitalia.     

野外条件下广聚萤叶甲对豚草的产卵选择

为探究影响广聚萤叶甲Ophraella communa LeSage选择豚草产卵的环境因素, 在南京城郊于2009年6月23日至9月1日豚草生长季节, 跟踪调查了60个豚草斑块上落卵数量动态, 运用跨栏模型分析了影响叶甲产卵以及产卵数量的因素。结果表明： （1）产卵发生随季节延长、 豚草被取食程度增大、 株高增长、 暴露环境中斑块增大而增加, 但随遮蔽环境中豚草斑块增大、 开花、 开花后季节延长、 季节延长情况下被取食程度增大、 开花后被取食程度增大等因素而降低; （2）落卵数量随季节延长、 豚草被取食程度增大、 暴露环境、 开花期被取食程度增大、 开花期株高增长等因素而增加, 但随豚草开花、 季节延长情况下被取食程度增大而减小; （3）落卵量随季节延长而增大的幅度在豚草营养生长期明显大于开花期, 在暴露环境中随季节延长而呈明显直线增大, 但在遮阴环境中先直线增加, 于10周后趋缓。研究结果说明, 影响产卵发生与落卵数量的因素不完全一致, 产卵发生与落卵数量主要受因子之间互作的影响, 而较少受到单因素的独立影响。     

Patch colonization by Trirhabda canadensis (Coleoptera: Chrysomelidae): effects of plant species composition and wind

Summary The goldenrod leaf beetle, Trirhabda canadensis, is known to respond to odors of host and non-host species in the laboratory. Here we report movements of T. canadensis in the field in response to volatile odors from monocultures and polycultures of host plants. Overall, beetles preferentially colonized plots with a higher density of host plants and lower diversity of allelochemicals, but under some wind conditions there were marked exceptions. At high windspeeds, they colonized whichever plot(s) was upwind. At low windspeeds, beetles colonized preferred plots even when they were not upwind. The data suggest that odor dispersion varies in a complex way with windspeed: at low windspeeds beetles received information from a wide are of vegetation and made choices while at high windspeeds information was available only from upwind plot(s).     

Ovipositional biology of Viburnum leaf beetle, Pyrrhalta viburni (Coleoptera: Chrysomelidae)

Pyrrhalta viburni Paykull, a new landscape pest in the United States, feeds in both the larval and adult stages on foliage of plants in the genus Viburnum. We measured lifetime oviposition capacity of mated and unmated females reared in the laboratory versus field-collected females, as well as ovipositional response to physical characteristics of the host plant. Both mated and unmated females produced eggs, but at different rates. Field-collected females and mated females reared in the laboratory laid similar numbers of egg masses containing similar numbers of eggs, but unmated females laid approximately one half as many eggs, the result primarily of smaller clutch size. Mated females reared in the laboratory had a preovipositional period of 11.4 +/- 1.7 versus 29 + 11.7 d for unmated females, and unmated females lived significantly longer than mated females. The angle and diameter of stems of V. trilobum, a very susceptible host, both greatly influenced oviposition; females laid most eggs on vertically oriented stems, and those of smallest diameter; when these factors were combined, stem diameter predominated. Females also had a very strong geotactic response, preferring to lay eggs on portions of stems toward gravity, even when stems were at fairly shallow angles.     

Preliminary life table of the spotted tortoise beetle,Aspidomorpha miliaris (Coleoptera: Chrysomelidae) in Sumatra

From December, 1981 to February, 1982, a population study of the spotted tortoise beetle, Aspidomorpha miliaris, feeding on a shrub-like morning glory, Ipomea carnea, was conducted in Padang, Sumatra with the construction of a life table.

1. Dissection of oothecae collected from the field after hatching clarified that the average egg mass size was 43.4 and hatching rate was 25.0%. Causes for egg mortality included: parasitism by a wasp, Tetrastichus sp. A(Europhidae) (49.8% of eggs laid), predation (12.8%), disappearance of egg masses (5.3%) and hatching failure (7.1%). An ant, Dolichoderus bituberculatus, visiting the extrafloral nectaries of the host plnts was responsible for predation and disappearance of the egg masses. The ants again attacked the larvae and pupae.
2. Larvae showed a gregarious habit for almost the entire larval period. Survival rates between two successive instars were low and constant, ranging from 70 to 90%, but only 1.3% of final (5th) instars become pupae (six individuals). Since the growth of host plants was extremely rapid, shortage of food was rare in larval stages. The sudden drop in numbers after 5th instar may be due to predation and/or dispersal of matured larvae from the host plants for pupation.
3. Pupae were attacked by three species of parasitic wasps:Tetrastichus sp. C, Pediobius elasmi (Eulophidae) and Cassidocida aspidomorphae (Tetracampidae). Among the six pupae, two were parasitized, one died of disease and two disappeared. Out of 4078 eggs laid, only one emerged to adult.

     

To the knowledge of the leaf beetle genus Cystocnemis (Coleoptera, Chrysomelidae)

Four subspecies of Cystocnemis discoidea are distinguished; two subspecies are described as new to science based on investigation of intraspecific variation in different parts of the species range, and ssp. gebleri was resurrected from synonymy. The ways of speciation in highland-hollow landscapes are discussed. The alpine subspecies C. discoidea oreas ssp. n. has an altibiome disjunction with the nominotypical subspecies. Similarity of the alpine subspecies of C. discoidea to the species from the subgenus Entomomela was found to be the reason of permanent confusion of representatives of these taxa. The subgenus Entomomela is transferred from the genus Oreomela to the genus Cystocnemis. A key to species and subspecies of the genus Cystocnemis is given.     

Host-plant effects on larval survival of a salicin-using leaf beetle Chrysomela aeneicollis Schaeffer (Coleoptera: Chrysomelidae)

Several species of willow leaf beetles use hostplant salicin to produce a defensive secretion that consists of salicylaldehyde. Generalist arthropod predators such as ants, ladybird beetles, and spiders are repelled by this secretion. The beetle larvae produce very little secretion when they feed on willows that lack salicylates, and salicin-using beetles prefer salicylate-rich willows over salicylate-poor ones. This preference may exist because the larvae are better defended against natural enemies on salicylate-rich willows. If this is true, the larvae should survive longer on those willows in nature. However, this prediction has not been tested. I determined the larval growth and survival of Chrysomela aeneicollis (Coleoptera: Chrysomelidae) on five willow species (Salix boothi, S. drummondiana, S. geyeriana, S. lutea, and S. orestera). These species differed in their salicylate chemistries and in leaf toughness but not in water content. The water content varied among the individual plants. Larval growth of C. aeneicollis did not differ among the five species in the laboratory, but it varied among the individual plants and it was related to the water content. In the field, C. aeneicollis larvae developed equally rapidly on the salicylate-poor S. lutea and on the salicylate-rich S. orestera. Larval survival was greater on S. orestera than on S. lutea in one year (1986), but there was no difference between them during three succeeding years. In another survivorship experiment, larval survival was low on the medium-salicylate S. geyeriana, but high on the salicylate-poor S. boothi and on S. orestera. Larval survival in the field was related to the larval growth and water content that had been previously measured in the laboratory. These results showed that the predicted relationship between the host plant chemistry and larval survival did not usually exist for C. aeneicollis. One possible reason for this was that the most important natural enemies were specialist predators that were unaffected by the host-derived defensive secretion. One specialist predator, Symmorphus cristatus (Hymenoptera: Eumenidae), probably caused much of the mortality observed in this study. I discuss the importance of other specialist predators to salicin-using leaf beetles.     

Reproductive and subsocial behaviour in the ovoviviparous leaf beetle Gonioctena sibirica (Coleoptera: Chrysomelidae)

Abstract.

• 1 In the spring, females of the leaf beetle Gonioctena sibirica deposited larvae on the ventral surface of growing young leaves situated on the apical position of shoots of the willow Salix bakko.
• 2 The parent females remained with the larvae usually on the underside of the basal part of leaves, facing toward the base of shoots. When other arthropods approached, the females temporarily moved towards these intruders, showing aggressive behaviour such as swinging the body or stamping the legs. Many females remained with their larvae until the larvae grew into the final (fourth) instar. No female produced an additional brood in the field.
• 3 Broods from which parent females were experimentally removed suffered higher mortality than those in which females were left intact. Arthropods such as spiders and ants were observed preying on the larvae. In contrast, the survivorship of broods from which females were removed and intruders were excluded with a sticky substance applied to the base of twigs was not different from that of control broods. These results demonstrate that the main mortality factor of offspring is pedestrian arthropod predators and females physically repel the predators.
• 4 Potentially alternative reproductive strategies, such as producing a large number of offspring by iteroparity and/or larger brood(s) with less or no care, seem to be inhibited in G.sibirica by larval dependence on growing young leaves which are temporally limited and by ovoviviparity which may have limited brood size.

     

Larva of the leaf beetle Labidostomis longimana (Coleoptera, Chrysomelidae, Clytrinae)

The first- and the last-instar larvae of the leaf-beetle Labidostomis longimana are described in detail for the first time. The last instar larva is morphologically close to L. sibirica larva and differs from it in the absence of a projection in the medial emargination of the labrum, in the presence of 7 spiniform setae on the tibiotarsus ventrally, 11–13 narrow simple setae on the tibiotarsus dorsally, and fine rugae on the larval case.     

Phylogeny and host-plant association in the leaf beetle genus Trirhabda LeConte (Coleoptera: Chrysomelidae)

The leaf beetle genus Trirhabda contains 26 described species from the United States and Canada, feeding on host plants from the families Asteraceae and Hydrophyllaceae. In this study, we present a phylogeny for the genus that was reconstructed from mitochondrial COI and 12S rRNA fragments, nuclear ITS2 rRNA, and morphological characters. Both parsimony and mixed-model Bayesian likelihood analyses were performed. Under both methods, the mitochondrial and nuclear partitions support the same backbone phylogeny, as do the combined data. The utility of the molecular data is contrasted with the low phylogenetic signal among morphological characters. The phylogeny was used to trace the evolution of the host-plant association in Trirhabda. The recovered phylogeny shows that although the host-plant association is phylogenetically conservative, Trirhabda experienced one shift to a distantly related host-plant family, 6 shifts between host-plant tribes, and 6 between genera within tribes. The phylogeny reveals that Trirhabda were plesiomorphically adapted to tolerate complex secondary compounds of its host plants and this adaptation is retained in Trirhabda species, as evidenced by multiple shifts from chemically simpler host plants back to the more complex host plants.     

广聚萤叶甲实验种群生命表

通过在(26±1)℃恒温条件下的饲养观察,组建了广聚萤叶甲实验种群的特定年龄生命表和生殖力表。结果表明:广聚萤叶甲卵、幼虫、蛹和产卵前期的历期分别为7.51、12.14、7.67和4.75d;各虫态的存活率变幅在77%～94%,其中以卵期存活率最高,3龄幼虫存活率最低,且种群存活曲线呈DeeveyⅡ型分布;单雌平均产卵量为193.8粒;种群趋势指数为36.95,世代平均历期为31.37d,内禀增长能力为0.095,周限增长率为1.10。     

Efficacy of imidacloprid for control of cereal leaf beetle (Coleoptera: Chrysomelidae) in barley

The toxicity of imidacloprid to the cereal leaf beetle, Oulema melanopus (L.), was measured under laboratory and field conditions. Insect mortality and plant damage were determined from artificial and natural infestations of O. melanopus applied to various growth stages of barley. All rates of imidacloprid formulated and applied as a seed treatment caused >90% mortality to cereal leaf beetle larvae when barley was infested with eggs at the 4-leaf stage, but were ineffective when barley was infested with eggs at the early tillering or flag-leaf stages of barley. This window of susceptibility influenced results obtained in field trials where peak larval emergence did not occur until the early tillering stage of barley. The resulting mortality in plants from treated seeds never exceeded 40% in the field. Foliar imidacloprid, however, caused >90% mortality in the field, and may be another option in the management of the cereal leaf beetle.     

Comparison of leaf beetle assemblages of deciduous trees canopies in Hungary (Coleoptera: Chrysomelidae)

The species richness and species composition of Coleoptera assemblages were investigated in deciduous tree canopies in Hungary. Apple and pear orchards were investigated in Nagykovácsi, Kecskemét and Sárospatak in 1990-94, and limes and maples in Keszthely in 1999-2002. Faunistic results and conclusions of these investigations were published elsewhere. Examination of the fauna of parks, avenues and other planted urban plant stocks has only begun to occupy researchers in the last decade in Hungary. The proportion of leaf-beetle species in the material gathered on maples and limes ranged between 17.0 and 21.3 per cent. The commonest leaf-beetle specimens collected in the lime canopy were Aphthona euphorbiae, Chaetocnema tibialis, Longitarsus lycopi, L. pellucidus, L. pratensis and L. succineus. The commonest on maple were Aphthona euphorbiae, Chaetocnema concinna, C. tibialis, Longitarsus lycopi, L. pellucidus, L. succineus, Phyllotreta cruciferae and P. vittula. This study presents the details on the composition of the chrysomelid communities that was compared by metric ordination using the Syntax 5.1 program.