Organization of the mitochondrial genomes of whiteflies,aphids, and psyllids (Hemiptera,Sternorrhyncha)

Background  

With some exceptions, mitochondria within the class Insecta have the same gene content, and generally, a similar gene order allowing the proposal of an ancestral gene order. The principal exceptions are several orders within the Hemipteroid assemblage including the order Thysanoptera, a sister group of the order Hemiptera. Within the Hemiptera, there are available a number of completely sequenced mitochondrial genomes that have a gene order similar to that of the proposed ancestor. None, however, are available from the suborder Sternorryncha that includes whiteflies, psyllids and aphids.     

Diversity of some insect fauna in industrial and non-industrial areas of West Bengal, India

The present work is designed to study diversity of five insect orders (viz., Hemiptera, Orthoptera, aculeate Hymenoptera, Lepidoptera and Coleoptera) in the industrial region of Haldia (India) and in non-industrial area of the same district and to evaluate the impact of industrialization on the biodiversity of those insect orders. The objective also extended to find out the possibility of existence of bioindicator, if any. Eight study sites were selected from the East part of Midnapur district covering 40 km aerial distance. Out of eight different study sites, five were distributed in and around Haldia industrial complex and three in industry-free area. During this study, a total of 120 species under 98 genera in 37 families of insects were collected. Binary data of 5 orders revealed that the species richness of Hemiptera, Orthoptera and Lepidoptera is higher in non-industrial zone in comparison to that of industrial zone. Aculeate Hymenoptera shows no particular trend whereas Coleoptera shows higher species richness in industrial areas. Results of multivariate analyses are compared with the species richness data for all the eight study sites. It is concluded that even in an apparently homogeneous ecological condition species richness may drastically change with the influence of industries. Total insect fauna decline by at least 23.33% is noticed in industrial areas. It is found that some species of lepidopteran, hemipteran and orthopteran insects are susceptible to industrial pollution and some of the members of these orders may be considered as a bioindicator group.     

Testing the suitability of insect orders as indicators for olive farming systems

• 1 A previous study suggested the use of certain insects groups as indicators for detecting organic olive farming in Southern Spain. To validate the use of these groups, insects were collected from olive orchards in Cordoba and Granada, comprising two Andalusian provinces with different surrounding landscapes.
• 2 Canopies were sampled using the branch‐beating technique during pre‐blooming and post‐blooming periods over 3 years in Granada (1999, 2000 and 2003) and 1 year in Cordoba (2003).
• 3 Using a nonparametric linear discriminant analysis method, based on the k‐nearest neighbour algorithm, two discriminant functions were constructed. A first discriminant model took into account interannual variability in Granada Province and the second model focused on environmental heterogeneity between the two provinces. Cross‐validation techniques, such as leave‐one‐out and split‐sample, were applied to the associated discriminant functions for each model to check their performance.
• 4 Even though differences existed with respect to the insect composition of the regions, the second model correctly classified 78.1% of the sampled blocks under the non‐organic and organic farming systems at the same time as taking into account two orders: Coleoptera and Hemiptera [excluding Euphyllura olivina olivina (Psyllidae) and the Heteroptera suborder]. The results suggest that the relative abundance of these groups in the post‐blooming period could constitute a potential bio‐indicator of organic olive farming system.

     

Seasonal pattern of insect abundance in the Brazilian cerrado

Abstract In Brazil, a severe dry season lasting for approximately 5 months and frequent fires make life difficult for cerrado insects. In certain aspects, the cerrado can be considered to be an understudied ecosystem; even basic information such as knowledge about the annual peak in abundance of different insect orders is unknown. Insect abundance patterns have only been investigated for a few groups in the cerrado region. Thus, our study concerns the temporal distribution of insect abundance in the savanna‐like vegetation of the central Brazilian cerrado (sensu stricto) in Distrito Federal. The region has a well‐defined, long dry season between May and September. The insects were sampled by window, malaise tent and pitfall traps within 1 year. We used a multiple linear regression to analyse the relationship between abundance of insects of each order and climate variables. A total of 50 127 individuals from 15 orders was collected. The orders were Coleoptera (26%), Hymenoptera (23%), Diptera (20.5%), Isoptera (20%), Homoptera (4%), Lepidoptera (4%), Orthoptera (1.5%) and Hemiptera (1%). The abundance of Diptera, Homoptera, Lepidoptera and Orthoptera was randomly distributed over time, Isoptera peaked in the first half of the wet season, Coleoptera and Hemiptera in the second half of the wet season and Hymenoptera in each season. A significant correlation was found only between Coleoptera and delayed climatic variables. There were no obvious trends that might help explain the abundance patterns observed. The study provides baseline information about phenological patterns of insect abundance and permits evaluation of this group as a resource for various food chains and different trophic levels.     

Insect drift over the northern Arabian sea in early summer

Air borne insects, mostly carried by wind currents, were trapped over the northern Arabian sea (16‡ to 20‡ N; 68‡ to 72‡ E), in the course of cruise No. 111, ORVSAGAR KANYA (March 14 to April 7, 1996). A total of 2,301 insects belonging to 8 different orders, 47 families and 173 species were trapped. Of these, Hymenoptera was represented by the largest number (1082), which was followed by Hemiptera (586), Diptera (552), Coleoptera (51), Neuroptera (10), Trichoptera (03), Lepidoptera (03) and Orthoptera (01). The trapped insects were mostly between 0.6 mm to over 11 mm long. The data was examined for α-diversity as well as for possible correlations between various parameters like the diversity index, size and number of insects trapped on one hand and the distance of the nearest land mass in wind direction, on the other. Deceased.     

Fine structure of the pyloric region and Malpighian papillae of protura (Insecta Apterygota)

The pyloric region of Eosentomon and Acerentomon (Insecta, Protura) is described. In both species the posterior cells of the midgut carry short microvilli. Beneath the epithelial cells there is a muscular pyloric sphincter for closing the intestinal lumen. Behind the sphincter is a wide pyloric chamber lined by cells with very long microvilli which point anteriorly toward the midgut. These cells regulate the passage of the intestinal contents into the hindgut. Secretions from the Malpighian papillae are emitted into the gut at this level. In Eosentomon three regions (R₁, R₂ and R₃) are visible in the Malpighian papillae, whereas in Acerentomon region R₁ is lacking. The R₁ region contains secretory cells with elaborate glycoprotein-containing granules. The R₂ region is composed of cells somewhat resembling the secretory cells of Malpighian tubules of insects. Presumably R₁ and R₂ cells emit secretions into the central cavity of each papilla. Cells of R₃ form a duct for the secretion. It is suggested that the R₂ region represents a basic excretory region, common to Protura, whereas the R₁ region, in Eosentomon, may be a specialized area performing supplementary excretory functions.     

Occurrence of proctolin in six orders of insects

Nine representatives of six orders of insects (Orthoptera, Diptera, Coleoptera, Hemiptera, Hymenoptera, Lepidoptera) were extracted and partially processed by means used in the recent isolation of proctolin, a pentapeptide transmitter candidate in insects. Each insect yielded a substance with pharmacological activity on cockroach proctodeal muscle similar to that of proctolin. Like the responses evoked by proctolin and nerve stimulation, responses to the purified extracts were inhibited by tyramine. All of the active substances behaved as proctolin when subjected to paper chromatography or high voltage paper electrophoresis at pH 6.4 and 3.5. Proctolin appears to be widely and perhaps universally present in the Insecta occurring in most at levels of 2 to 9 μg/kg body weight.     

数学形态学在昆虫分类学上的应用研究.Ⅰ.在目级阶元上的应用研究

根据昆虫图像,对半翅目（Hemiptera）、鳞翅目（Lepidoptera）、鞘翅目（Coleoptera）的34种昆虫提取形状参数、叶状性、球状性等7项数学形态特征进行了统计分析,从而论证了各项数学形态特征在目级昆虫分类阶元上作为分类特征的可行性和可靠性,并从数学形态学角度对所涉及到的同阶元昆虫类群的亲缘关系做了描述。结果表明,在作为目级阶元分类特征时,各项特征的可靠性依次为：(似圆度、偏心率、亮斑数)＞(叶状性、球状性、圆形性)＞形状参数。由这些特征的差异显著性可知,从数学形态特征角度讲,3个目的亲缘关系远近大小依次为：半翅目与鞘翅目＞半翅目与鳞翅目＞鳞翅目与鞘翅目。     

Morphological dissection of behavior: thoracic musculature clarifies independent development of jumping mechanisms between sister groups,planthoppers and leafhoppers (Insecta: Hemiptera: Auchenorrhyncha)

Morphological and behavioral characters are frequently examined for comparative studies. Unlike morphology, a single behavioral trait is difficult to subdivide as multiple characters, even when achieved by many evolutionary changes. Therefore, when similar behavioral traits evolved independently among closely related taxa, their distinction is difficult. Almost all members of the suborder Auchenorrhyncha (Insecta: Hemiptera) possess a jumping ability that uses metathoracic muscles, and this behavioral trait has been regarded as a synapomorphy. In this study, the anatomical observations of metathoracic muscles revealed that highly elaborated jumping ability was gained independently within the suborder, although the evolution of jumping ability might have been initiated at their common ancestor. Our results provide an example of identifying a true evolutionary pathway by dissecting a behavioral character into mechanical elements.     

Abundance–body mass relationships among insects along a latitudinal gradient

Abstract We investigated the relationship between abundance and body size (body mass) of 162 insect herbivore species on the host plant Acacia falcata along its entire coastal latitudinal distribution (eastern Australia), spanning a gradient in mean annual temperature of 4.3°C. We extend previous research by assessing these relationships at different spatial scales (latitudes pooled, among latitudes and within latitudes) and at different taxonomic levels (insect phytophages pooled, phytophagous Coleoptera and Hemiptera, and five component suborders/superfamilies). Insect species were collected from two orders (Hemiptera and Coleoptera) and five component suborders/superfamilies. There were no consistent trends in the relationships (linear or polygonal/hump‐shaped) between abundance and body mass when latitudes were pooled, among latitudes, or when phytophagous insect species were separated into their component suborder/superfamily groups. The reason for the lack of consistent trends might be due to the insect herbivores not fully exploiting their host plant and the relative absence of competition among herbivore species for food resources. This is further assessed in relation to the lack of a consistent pattern in species richness of Coleoptera and Hemiptera herbivores from the same dataset and rates of chewing and sap‐sucking herbivory along the same latitudinal gradient. Future studies of abundance–body size relationships are discussed in relation to sampling across environmental gradients and accounting for the influence of host plant identity and insect phylogeny.     

中国半翅目等29目昆虫2020年新分类单元

以中国半翅目等29目昆虫类群(除鞘翅目、双翅目、鳞翅目、膜翅目之外的其他目)为研究对象, 基于2020年度发表的新分类单元与文献资料, 编制了物种名录, 分析了新分类单元的地理分布与模式标本存放情况等。2020年, 中国半翅目等29目昆虫共描述349个新分类单元, 包括新属35个, 新种311个, 新亚种3个; 新种发表的热点地区在我国的西南山地及其邻近地区。模式标本存放单位多达69家, 其中正模标本主要存放在国内保藏机构, 而境外机构保藏的标本较少且以副模标本为主。本年度描述的349个新分类单元由356位作者所贡献, 共发表文献182篇; Zootaxa和ZooKeys是发表的主要期刊。本次调查为进一步深入研究物种演化的时空格局及生物多样性保护提供了基础数据。同时, 由于人类面临生物多样性急剧下降的威胁, 应加快大数据平台的建设及其多样化信息的挖掘, 支撑生物多样性的研究和保护。     

Incidence of Wolbachia in aquatic insects

Wolbachia is a genus of intracellular bacteria typically found within the reproductive systems of insects that manipulates those systems of their hosts. While current estimates of Wolbachia incidence suggest that it infects approximately half of all arthropod species, these estimates are based almost entirely on terrestrial insects. No systematic survey of Wolbachia in aquatic insects has been performed. To estimate Wolbachia incidence among aquatic insect species, we combined field‐collected samples from the Missouri River (251 samples from 58 species) with a global database from previously published surveys. The final database contained 5,598 samples of 2,687 total species (228 aquatic and 2,459 terrestrial). We estimate that 52% (95% CrIs: 44%–60%) of aquatic insect species carry Wolbachia, compared to 60% (58%–63%) of terrestrial insects. Among aquatic insects, infected orders included Odonata, Coleoptera, Trichoptera, Ephemeroptera, Diptera, Hemiptera, and Plecoptera. Incidence was highest within aquatic Diptera and Hemiptera (69%), Odonata (50%), and Coleoptera (53%), and was lowest within Ephemeroptera (13%). These results indicate that Wolbachia is common among aquatic insects, but incidence varies widely across orders and is especially uncertain in those orders with low sample sizes such as Ephemeroptera, Plecoptera, and Trichoptera.     

数学形态学在昆虫分类学上的应用研究.Ⅰ.在目级阶元上的应用研究

根据昆虫图像,对半翅目（Hemiptera）、鳞翅目（Lepidoptera）、鞘翅目（Coleoptera）的34种昆虫提取形状参数、叶状性、球状性等7项数学形态特征进行了统计分析,从而论证了各项数学形态特征在目级昆虫分类阶元上作为分类特征的可行性和可靠性,并从数学形态学角度对所涉及到的同阶元昆虫类群的亲缘关系做了描述。结果表明,在作为目级阶元分类特征时,各项特征的可靠性依次为：(似圆度、偏心率、亮斑数)＞(叶状性、球状性、圆形性)＞形状参数。由这些特征的差异显著性可知,从数学形态特征角度讲,3个目的亲缘关系远近大小依次为：半翅目与鞘翅目＞半翅目与鳞翅目＞鳞翅目与鞘翅目。     

Geographic pattern of host‐associated differentiation in the cotton fleahopper,Pseudatomoscelis seriatus

Host‐associated differentiation (HAD) is the occurrence of genetically distinct, host‐associated lineages. Most of the cases of HAD in phytophagous insects have been documented in specialist insects inhabiting feral ecosystems or in generalist parthenogens in agroecosystems. Herein we report HAD in the cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), a native, generalist, non‐parthenogenetic insect feeding on native wild hosts [horsemint, Monarda punctata L. (Lamiaceae) and woolly croton, Croton capitatus Michx. (Euphorbiaceae)] and on cotton [Gossypium hirsutum L. (Malvaceae)] in the USA. Examination of genome‐wide genetic variation with AFLP markers and Bayesian analyses of P. seriatus associated with three different host plant species at five locations in Texas revealed a geographic pattern of HAD. The geographic pattern of HAD corresponded with differences in precipitation among the locations studied. In three locations, two distinct lineages of P. seriatus were found in association with horsemint and cotton/woolly croton, whereas in two other locations, populations associated with the different host plants studied were panmictic. We suggest that precipitation differences among locations translate into heterogeneity in vegetation distribution, composition, and phenology, which altogether may contribute to the observed geographic pattern of HAD.     

Changes in the mechanical properties of the extensible cuticle of Rhodnius through the fifth larval instar

The ultimate tensile strength (σ_UT) and the modulus of elasticity (E) of Rhodnius extensible cuticle are σ_UT = 2.20 × 10⁷ Nm^?2, E = 2.43 × 10⁸ Nm^?2 (unplasticised); σ_UT = 1.43 × 10⁷ Nm^?2, E = 9.45 × 10⁶ Nm^?2 (plasticised with 5HT) and σ_UT = 9.05 × 10⁶ Nm, E = 2.46 × 10⁶ Nm^?2 (plasticised in pH 5 buffer).The mechanical properties of cuticle from insects which have deposited additional layers of cuticle after they have been fed differ from those of cuticle from unfed insects. This is possibly due to the different composition of the additional cuticle: it is suggested that the post-feeding cuticle is providing protection and a template for the next instars cuticle.The maximum strain of extensible cuticle from starved insects is related to the amount of matrix protein present.     

Three-way interaction among plants,bacteria, and coleopteran insects

Main conclusion

Coleoptera, the largest and the most diverse Insecta order, is characterized by multiple adaptations to plant feeding. Insect-associated microorganisms can be important mediators and modulators of interactions between insects and plants. Interactions between plants and insects are highly complex and involve multiple factors. There are various defense mechanisms initiated by plants upon attack by herbivorous insects, including the development of morphological structures and the synthesis of toxic secondary metabolites and volatiles. In turn, herbivores have adapted to feeding on plants and further sophisticated adaptations to overcome plant responses may continue to evolve. Herbivorous insects may detoxify toxic phytocompounds, sequester poisonous plant factors, and alter their own overall gene expression pattern. Moreover, insects are associated with microbes, which not only considerably affect insects, but can also modify plant defense responses to the benefit of their host. Plants are also frequently associated with endophytes, which may act as bioinsecticides. Therefore, it is very important to consider the factors influencing the interaction between plants and insects. Herbivorous insects cause considerable damage to global crop production. Coleoptera is the largest and the most diverse order in the class Insecta. In this review, various aspects of the interactions among insects, microbes, and plants are described with a focus on coleopteran species, their bacterial symbionts, and their plant hosts to demonstrate that many factors contribute to the success of coleopteran herbivory.

     

What genes and chromosomes say about the origin and evolution of insects and other arthropods

At the turn of the 21st century, the use of molecular and molecular cytogenetic methods led to revolutionary advances in systematics of insects and other arthropods. Analysis of nuclear and mitochondrial genes, as well as investigation of structural rearrangements in the mitochondrial chromosome convincingly supported the Pancrustacea hypothesis, according to which insects originated directly from crustaceans, whereas myriapods are not closely related to them. The presence of the specific telomeric motif TTAGG confirmed the monophyletic origin of arthropods (Arthropoda) and the assignment of tongue worms (Pentastomida) to this type. Several different types of telomeric sequences have been found within the class of insects. Investigation of the molecular organization of these sequences may shed light on the relationships between the orders Diptera, Siphonaptera, and Mecoptera and on the origin of such enigmatic groups as the orders Strepsiptera, Zoraptera and suborder Coleorrhyncha.     

What gene and chromosomes say about the origin and evolution of insects and other arthropods

At the turn of the 21st century, the use of molecular and molecular cytogenetic methods led to revolutionary advances in systematics of insects and other arthropods. Analysis of nuclear and mitochondrial genes, as well as investigation of structural rearrangements in the mitochondrial chromosome convincingly supported the Pancrustacea hypothesis, according to which insects originated directly from crustaceans, whereas myriapods are not closely related to them. The presence of the specific telomeric motif TTAGG confirmed the monophyletic origin of arthropods (Arthropoda) and the assignment of tongue worms (Pentastomida) to this type. Several different types of telomeric sequences have been found within the class of insects. Investigation of the molecular organization of these sequences may shed light on the relationships between the orders Diptera, Siphonaptera, and Mecoptera and on the origin of such enigmatic groups as the orders Strepsiptera, Zoraptera and suborder Coleorrhyncha.