Hemiptera Research Articles

The resistance of the jujube (Ziziphus jujuba) to the devastating insect pest Apolygus lucorum (Hemiptera, Insecta) involves the jasmonic acid signaling pathway

Apolygus lucorum (Hemiptera, Insecta), cosmopolitan true bug, is a major pest of the Chinese jujube (Ziziphus jujuba). To propose control measures of A. lucorum, we investigated the molecular mechanisms of resistance in two varieties of jujube (wild jujube and winter jujube) with different sensitivities to this pest. We monitored changes of two species of jujube in the transcriptome, jasmonic acid (JA) and salicylic acid (SA) content, and the expression of genes involved in signaling pathways. The preference of A. lucorum for jujube with exogenous SA and methyl jasmonate (MeJA) were also examined. The results showed that wild jujube leaves infested by A. lucorum showed stronger resistance and non-selectivity to A. lucorum than winter jujube. By comparing data from the A. lucorum infested plants with the control, A total of 438 and 796 differentially expressed genes (DEGs) were found in winter and wild jujube leaves, respectively. GO analysis revealed that biological process termed “plant–pathogen interactions”, “plant hormone transduction” and “phenylpropanoid biosynthesis”. Most of DEGs enriched in JA pathways were upregulated, while most DEGs of SA pathways were downregulated. A. lucorum increased the JA content but decreased the SA content in jujube. Consistently, the JA and SA contents in winter jujube were lower than those in wild jujube leaves. The key genes ZjFAD3, ZjLOX, ZjAOS, ZjAOC3 and ZjAOC4 involved in JA synthesis of jujube leaves were significantly up-regulated after A. lucorum infestation, especially the expression and up-regulation ratio of ZjFAD3, ZjLOX and ZjAOS in wild jujube were significantly higher than those in winter jujube. MeJA-treated jujube showed an obvious repellent effect on A. lucorum. Based on these findings, we conclude that A. lucorum infestation of jujube induced the JA pathway and suppressed the SA pathway. In jujube leaves the ZjFAD3, ZjLOX and ZjAOS played important roles in increasing of JA content in jujube leaves. Thus, JA played an important role in repelling and resisting against A. lucorum in jujube.

New Information about Bio-ecology, Life Cycle, Habitat, Geographic Distribution and Taxonomy of the Platygastridae Family (Insecta: Hymenoptera)

The Platygastridae are egg parasitoids of several insect orders and also of spiders. The family has hosts differentiated by subfamily: They are egg parasitoids of the orders Coleoptera and Hemiptera. The subfamily Scelioninae behave as parasitoids of eggs of Aranae and of several orders of insects such as Orthoptera and Grylloptera. Scelioninae. parasitoids of Aranae eggs and several insect orders: Orthoptera, Grylloptera, Hemiptera, and Coleoptera eggs. The purpose of this paper is to report new information about bio-ecology, life cycle, habitat, geographic distribution and taxonomy of the Platygastridae Family. For this review, the bibliographic search used the following databases: Scopus (https://www.scopus.com), Science Direct (https://www.sciencedirect.com), Scielo (https://scielo.org/es/), Web of Science (https://www.webofscience.com/wos/woscc/basic-search), ORCID (https://orcid.org) and Google scholar (https://scholar.google.com) between June 2022 and October 2022. The articles were published from 1972 to 2022 in indexed scientific research, book scientific chapters, theses banks, university dissertations, national and international scientific articles, scientific journals, documents and even in general journals when considered of interest. The main terms used were: Parasitic Hymenoptera, parasitoid, hosts, Platygastridae, and egg parasitoids.

Big-eyed bugs of the Malagasy Region (Hemiptera: Heteroptera: Lygaeoidea: Geocoridae)

A synopsis of the geocorine true bugs distributed in the Malagasy biogeographic region is presented, including the description Geocoris (Piocoris) petofii sp. n. and proposal of the new synonymy Geocoris (Geocoris) insularis China, 1955 = Geocoris (Geocoris) pallidipennis mauritii Stål, 1854. Keys, diagnoses, taxonomic notes, and distribution data for discussed species are provided.

Histamine excretion in common indoor and hematophagous arthropods.

Histamine is a biogenic amine that regulates multiple physiological functions in diverse organisms, specifically playing a central role in the mammalian immune response. The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), excretes histamine in large amounts in its feces as a component of its aggregation pheromone, which contaminates homes. The potential health risks associated with the presence of indoor histamine are unclear, but to predict future exposure risks, it is critical that we understand if other arthropods excrete histamine in any discernible phylogenetic pattern. In the present study, we evaluated histamine excretion by various arthropods; specifically those commonly found in large numbers indoors, other hematophagous species, and other species in the order Hemiptera. To evaluate arthropods for histamine excretion, rearing containers for each arthropod were swabbed and/or the harborage substrates were collected. Samples were then analyzed for the presence of histamine using gas chromatography-mass spectrometry. For those arthropods where histamine was present above the method detection limit, total histamine excretion was quantified over a period of 2 wk. Our results indicate that histamine excretion is limited to hematophagous hemipterans (bed bugs, bat bugs, tropical bed bugs, and kissing bugs), suggesting that indoor histamine contamination in the United States can be primarily linked to bed bugs.

A test of the Geographic Mosaic Theory of Coevolution: investigating widespread species of Amazonian Protium (Burseraceae) trees, their chemical defenses, and their associated herbivore faunas

IntroductionPlants and their insect herbivores represent a large fraction of the species in Amazonian forests and are often directly implicated in the origin and maintenance of biodiversity at local and regional scales. How these interactions may change over geographic distance is unknown because very few studies have investigated the herbivore fauna and defense chemicals of any host plant species at multiple sites in tropical forests. One hypothesis, the Geographic Mosaic Theory of Coevolution, predicts that if herbivore assemblages turn over in different parts of a plant’s range, then plant defense chemicals should also change, reflecting local selection pressures.MethodsWe tested this theory by studying 12 species of Protium (Burseraceae) trees that occur in both Iquitos, Peru, and Manaus, Brazil, in rainforests separated by 1500 km. We surveyed all insects observed directly feeding on the plants in both locations for 48 weeks in Manaus and 64 weeks in Iquitos. We analyzed the secondary metabolites in the leaves of all species in both locations using GC/MS and HPLC.Results and DiscussionAlthough in both locations we found that Protium herbivores were dominated by insects from the orders Hemiptera, Coleoptera and Lepidoptera, we found almost complete turnover in the herbivore species composition in the two sites, and each host plant species had a different assemblage of herbivores in each location. Comparing the phylogenetic beta-diversity, we found low similarity in herbivore phylogenetic relatedness between host plant species in the two locations. However, the secondary metabolites found within a Protium species were similar across the two locations. We found no strong evidence that individuals from a host plant species in Iquitos or Manaus expressed locally-adapted defense chemicals, as individuals from geographic locations did not form clusters when looking at patterns of chemical similarity. These results are not consistent with the Geographic Mosaic Theory of Coevolution. The most intriguing pattern we found was a strong correlation between the diversity of herbivores per host plant species in both locations. We also found that plants with high chemical richness had lower numbers of herbivore species and numbers of total herbivores in both locations. We conclude that high chemical diversity is the most effective strategy for Protium trees to reduce insect herbivore attacks. We speculate that each secondary metabolite is effective at repelling only a few insect herbivores, and that different chemicals are likely effective in different parts of a plants’ geographic range. Future studies should investigate additional locations and additional natural enemies (i.e., fungal pathogens) to test the hypothesis that chemical diversity reduces attack from natural enemies and may explain the ecological and evolutionary success of rainforest trees over time and space.

Potentiality assessment of solar based LED light trap as pest management tool in tea (Camellia sinensis L.)

Insect pest is a very common problem in tea garden where they caused a huge loss in each year. The study was conducted to measure the potentiality of a solar based LED light trap as an eco-friendly pest management technology in the tea garden of Bangladesh. The results showed that the highest number of insects from Coleoptera (3526) and Hemiptera (557) orders were captured under the solar based LED light trap while it was lowest in Hymenoptera (47) and Orthoptera (3). The study results also indicated that in an average of 9 days, total captured insects (number) were 725, 244, 146, 112, and 85 at 6-7, 7-8, 8-9, 9-10, and 10-11 pm, respectively while it was 656, 1004, 566, 3970, 602, 489, 680, 620 and 3222 at 1st to 9th days, respectively. Hence, the average decreasing rate with time (hourly) was computed at 66.34, 40.16, 23.29, and 24.11% compared to the 1st hour (6-7 pm). The average captured pattern of the insects compared to the 1st days was decreased or vice-versa. From 6.00 pm to 11.00 am, the initial light intensity was measured at 28 lux which raised up to 245 lux at 8.00 pm after that it down drastically. Light intensity has a positive relation with insect capture. Most of the Coleopteran and Hemipteran insects were captured under low light intensity in the early evening (6.00 pm). Therefore, the study suggested that the solar based LED light trap might have the potential to reduce a great number of tea pests in the tea garden.

Plant invasion and fragmentation indirectly and contrastingly affect native plants and grassland arthropods

Plant invasion and habitat fragmentation have a detrimental effect on biodiversity in nearly all types of ecosystems. We compared the direct and indirect effects of the invasion of the common milkweed (Asclepias syriaca) on biodiversity patterns in different-sized Hungarian forest-steppe fragments. We assessed vegetation structure, measured temperature and soil moisture, and studied organisms with different ecological roles in invaded and non-invaded sites of fragments: plants, bees, butterflies, flower-visiting wasps, flies, true bugs, and spiders. Temperature and soil moisture were lower in invaded than in non-invaded area. Milkweed had a positive effect on plant species richness and flower abundance. In contrast, we mainly found indirect effects of invasion on arthropods through alteration of physical habitat characteristics and food resources. Pollinators were positively affected by native flowers, thus, milkweed indirectly supported pollinators. Similarly, we found higher species richness of herbivores in invaded sites than control sites, as species richness of true bugs also increased with increasing plant species richness. Predators were positively affected by complex vegetation structure, higher soil moisture and lower temperature. Furthermore, increasing fragment size had a strong negative effect on spider species richness of non-invaded sites, but no effect in invaded sites. Especially, grassland specialist spiders were more sensitive to fragment size than generalists, whereas generalist spider species rather profited from invasion. Although milkweed invades natural areas, we did not identify strong negative effects of its presence on the diversity of the grassland biota. However, the supportive effect of milkweed on a few generalist species homogenises the communities. The rate of invasion might increase with increasing fragmentation, therefore we recommend eliminating invasive plants from small habitat fragments to preserve the native biota. Focusing also on generalist species and revealing the indirect effects of invasions are essential for understanding the invasion mechanisms and would support restoration efforts.

DNA metabarcoding reveals seasonal changes in diet composition across four arthropod-eating lizard species (Phrynosomatidae: Sceloporus).

Diet composition and its ecological drivers are rarely investigated in coexisting closely related species. We used a molecular approach to characterize the seasonal variation in diet composition in four spiny lizard species inhabiting a mountainous ecosystem. DNA metabarcoding revealed that the lizards Sceloporus aeneus, S. bicanthalis, S. grammicus, and S. spinosus mostly consumed arthropods of the orders Hemiptera, Araneae, Hymenoptera, and Coleoptera. The terrestrial lizards S. aeneus and S. bicanthalis mostly predated ants and spiders, whereas the arboreal-saxicolous S. grammicus and saxicolous S. spinosus largely consumed grasshoppers and leafhoppers. The taxonomic and phylogenetic diversity of the prey was higher during the dry season than the rainy season, likely because reduced prey availability in the dry season forced lizards to diversify their diets to meet their nutritional demands. Dietary and phylogenetic composition varied seasonally depending on the species, but only dietary composition varied with altitude. Seasonal dietary turnover was greater in S. spinosus than in S. bicanthalis, suggesting site-specific seasonal variability in prey availability; no other differences among species were observed. S. bicanthalis, which lives at the highest altitude in our study site, displayed interseasonal variation in diet breadth. Dietary differences were correlated with the species' feeding strategies and elevational distribution, which likely contributed to the coexistence of these lizard species in the studied geographic area and beyond.

DNA barcode-based survey documents underestimated diversity and intricate phylogeographic patterns of aquatic Heteroptera in an endangered Balkan biodiversity hotspot: ancient Lake Skadar basin

Lake Skadar with its surrounding springs, wetlands and larger affluents is among the most diverse freshwater ecosystems in the Mediterranean region and a key biodiversity/endemism hotspot in Europe. It is also highly endangered due to climate change and rapid tourism development in the area. Being abundant, diverse and mostly predatory, true aquatic bugs play an important role in the functioning of freshwater ecosystems and are used as indicators of aquatic habitat quality. Nevertheless, this taxonomic group has been scarcely studied in the area. Our survey provides the first comprehensive DNA barcode library for 24 out of 25 species of aquatic Heteroptera collected in the Skadar Lake basin and adjacent regions. By this, we extend the list of species known from the area by 60%. In the case of three species, Notonecta maculata, Hydrometra stagnorum and Nepa cinerea, we detected multiple highly divergent, and also new BINs indicating possible taxonomic inconsistencies, the potential for (pseudo)cryptic diversity and intricate phylogeographic patterns. We show that presumably well-known hotspots, such as Lake Skadar region, are heavily understudied regarding even the prominent insect taxa and, thus, particularly vulnerable to undocumented biodiversity loss. Finally, we underline the value of simple DNA-barcoding-based surveys for providing reference barcode libraries for effective biomonitoring and signalling taxonomic and biogeographic issues.

Small grassland fragments and connectivity support high arthropod functional diversity in highly modified landscapes

Abstract Grassland ecosystems undergo dramatic habitat loss and fragmentation worldwide due to agricultural expansion and intensification. Among different taxonomic groups, grassland arthropods are particularly sensitive to this process and, therefore, are exposed to considerable risk. Although many studies focus on land use impacts on arthropod diversity, these mostly consider taxonomic diversity and neglect trait‐mediated functional responses. However, studying functional diversity often provides more accurate insights into ecosystem processes. Here, we assessed the effect of fragment size and connectivity on the functional composition (community‐weighted mean trait values) and diversity (Rao's quadratic entropy) of two diverse and abundant arthropod groups: spiders and true bugs. We assigned functional traits for more than 300 species collected from 30 sandy steppe (forest‐steppes) and 30 loess steppe fragments (kurgans) in the southern part of the Hungarian Great Plain. Functional responses to fragmentation were observed for spiders in forest‐steppes and for true bugs in kurgans. We found higher functional diversity in better‐connected fragments for spiders and in small fragments for both groups. We collected small, humidity‐preferring and web‐building spiders in small fragments, and there were more ballooning spiders with moist habitat preferences in well‐connected fragments. Furthermore, increasing grassland connectivity resulted in a significantly higher proportion of polyphagous and humidity‐preferring individuals in the true bug communities. Our results highlight the importance of small grassland fragments in maintaining high arthropod functional diversity. Even small fragments in a well‐connected grassland network can promote ecosystem functioning and associated services within human‐dominated landscapes.

Autorecoding A-to-I RNA editing sites in the Adar gene underwent compensatory gains and losses in major insect clades.

As one of the most prevalent RNA modifications in animals, adenosine-to-inosine (A-to-I) RNA editing facilitates the environmental adaptation of organisms by diversifying the proteome in a temporal-spatial manner. In flies and bees, the editing enzyme Adar has independently gained two different autorecoding sites that form an autofeedback loop, stabilizing the overall editing efficiency. This ensures cellular homeostasis by keeping the normal function of target genes. However, in a broader range of insects, the evolutionary dynamics and significance of this Adar autoregulatory mechanism are unclear. We retrieved the genomes of 377 arthropod species covering the five major insect orders (Hemiptera, Hymenoptera, Coleoptera, Diptera, and Lepidoptera) and aligned the Adar autorecoding sites across all genomes. We found that the two autorecoding sites underwent compensatory gains and losses during the evolution of two orders with the most sequenced species (Diptera and Hymenoptera), and that the two editing sites were mutually exclusive among them: One editable site is significantly linked to another uneditable site. This autorecoding mechanism of Adar could flexibly diversify the proteome and stabilize global editing activity. Many insects independently selected different autorecoding sites to achieve a feedback loop and regulate the global RNA editome, revealing an interesting phenomenon during evolution. Our study reveals the evolutionary force acting on accurate regulation of RNA editing activity in insects and thus deepens our understanding of the functional importance of RNA editing in environmental adaptation and evolution.

The ootheca of Libyaspis flavosparsa (Montandon) (Heteroptera: Plataspidae), with a review of ootheca-production in Heteroptera and other Insecta

Parental care behaviours including the defence of oviposited eggs are common strategies to increase the fitness of offspring in animals. Among insects, Hemiptera, the true bugs (Heteroptera) and allies, show a wide range of such strategies. Females of some heteropteran species in the family Plataspidae, in addition to standard maternal care of eggs and early instar nymphs, provide protection of eggs by forming an ootheca, a complex structure coating the egg batch. Although not homologous across the insect taxa in which oothecae occur, structures referred to as oothecae are relatively common in insects, but the literature has so far not been summarized comprehensively. The goals of the present study are twofold. First, we provide a detailed description of the egg and ootheca of the tropical plataspid species Libyaspis flavosparsa (Montandon). The oothecal material of Plataspidae originates from a modified epithelium of the midgut thus represents a unique situation within all insects. Second, the known occurrences of oothecae in Insecta are summarized and discussed. This study provides a basis for future investigations both into the ootheca in Heteroptera and in other insects.

Relationships between Land Use Changes and Benthic Macroinvertebrates’ Community Structure in an East African Riverine Environment

Anthropogenic land use activities affects the health status of river ecosystems in supporting aquatic biodiversity. Undisturbed wetlands ensure water bodies are ecologically healthy for community livelihoods. Recent years have witnessed degradation of aquatic ecosystems and this has devastating effects on the environment and community livelihoods. One of such wetlands is river Isiukhu of western Kenya. This study analysed water physico-chemical parameters and benthic macroinvertebrates’ assemblages of River Isiukhu between August to November, 2022. Four sampling stations were selected along the longitudinal river gradient based on anthropogenic impact and dominance of land use activities. Sampling stations were classified as ‘very high’, ‘high’, ‘moderate’ and ‘low’ and rated 4,3,2 and 1 respectively, depending on the anthropogenic impact. Macroinvertebrates were sampled using D-frame net and classified using appropriate keys. Anthropogenic activities and habitat characteristics were noted and recorded. Water quality parameters were determined in situ. Macroinvertebrates’ population indices were calculated to determine community structure. Sorenson’s Coefficient quantified similarities of species in different stations. Pearson correlation and ANOVA tested the study hypothesis. About 1,391 invertebrates were collected belonging to 12 orders, 32 families and 30 genera. Orders Ephemeroptera, Hemiptera, Diptera and Coleoptera recorded highest percentage taxonomical composition. Upper pristine stations (F and G) supported more species richness and diversity than lower stations (L and T). Macroinvertebrates’ communities in terms of diversity, abundance, richness, evenness, and functional feeding groups responded differently to impacts of anthropogenic activities, due to their varied adaptation traits. Water quality varied significantly between sampling stations (ρ <0.05). Close relationship existed between land use activities and species diversity (r=0.8; ρ < 0.05); richness (r=0.8779; ρ < 0.05); evenness (r=0.1067; ρ < 0.05); and abundance (r=0.962; ρ < 0.05). The study recommends the need to conserve riparian vegetation as a way of mitigating and adapting to the impact climate change on stream ecosystem.

Ontogenetic change in effectiveness of chemical defence against different predators in Oxycarenus true bugs.

Many prey species change their antipredator defence during ontogeny, which may be connected to different potential predators over the life cycle of the prey. To test this hypothesis, we compared reactions of two predator taxa - spiders and birds - to larvae and adults of two invasive true bug species, Oxycarenus hyalinipennis and Oxycarenus lavaterae (Heteroptera: Oxycarenidae) with life-stage-specific chemical defence mechanisms. The reactions to larvae and adults of both true bug species strikingly differed between the two predator taxa. The spiders were deterred by the defences of adult bugs, but the larval defences were ineffective against them. By contrast, birds attacked the larvae considerably less often than the adult bugs. The results indicate a predator-specific ontogenetic change in defence effectiveness of both Oxycarenus species. The change in defence is likely linked to the life-stage-specific composition of secretions in both species: whereas secretions of larvae are dominated by unsaturated aldehydes, secretions of adults are rich in terpenoids, which probably serve dual function of defensive chemicals and pheromones. Our results highlight the variation in defence between different life stages and the importance of testing responses of different types of predators.

Soil macrofauna diversity and weed dynamics in response to different methods of weed control in smallholder rubber farming

Abstract. Chaniago I, Yulistriani, Umami IM, Bukhari ZZ. 2023. Soil macrofauna diversity and weed dynamics in response to different methods of weed control in smallholder rubber farming. Biodiversitas 24: 3106-3113. Weeds interference in rubber farmland may reduce latex yield. Farmers apply herbicides to control weeds. However, the herbicide not only controls weed but also affects the presence of soil macrofauna. A study has been conducted to determine the effect of different method of weed control on soil macrofauna and weeds at smallholder rubber farming at Pulau Punjung, Dharmasraya District, West Sumatra, Indonesia. The experiment was conducted in a completely randomized block design with 6 treatments and 4 pseudo-replications. Treatment was mechanical control, without weed control, and 4 doses of herbicide glyphosate+metsulfuron-methyl (1.5 L ha-1 + 15 g ha-1, 2 L ha-1 + 15 g ha-1, 2.5 L ha-1 + 15 g ha-1, 3 L ha-1 + 15 g ha-1) with 400 L ha-1 of volume. Pitfall traps were used to collect the soil macrofauna. Data were analysis with ANOVA for weed and soil macrofauna in response to different methods of weed control. Results demonstrated that the application of glyphosate+metsulfuron-methyl herbicide significantly suppressed weeds higher than that of other methods of weed control (p<0.05). Para grass (Brachiaria mutica (Forssk.) Stapf) was the most dominant weed but has been affected most by 3 L ha-1 + 15 g ha-1 herbicide mixture. Soil macrofauna of the order Hemiptera was affected most by the application of herbicide with a total reduction of 71.58% of number of individuals at 12 weeks after application of herbicide. In general, different weed control methods resulted in varied numbers of orders and individuals of the soil macrofauna.

Diversity, domain duplication, birth‐and‐death and adaptive evolution of fatty acyl‐CoA reductase genes in Hemiptera

AbstractFatty acyl‐CoA reductases (FARs) play an important role in the synthesis of fatty alcohols in various organisms. Based on the important function of FAR genes, they can be used as a potential molecular target for controlling agricultural pests. Although the FAR genes have been studied in a number of insects, the gain, loss, and molecular evolution of FAR genes between different Hemipteran species still require comprehensive and systematic study. This study systematically identified and analysed 352 FAR genes from 12 Hemipteran species, including six typical true bug species, Cimex lectularius, Apolygus lucorum, Halyomorpha halys, Oncopeltus fasciatus, Rhodnius prolixus and Gerris buenoi. The number of FAR genes per species ranged from 17 to 43, and a phylogenetic analysis showed that the identified FAR genes of Hemiptera can be classified into 11 clades. The gain and loss of FAR genes have occurred in some Hemipteran species. These FAR genes conform to the birth‐and‐death model in the evolutionary process. Through selection pressure analysis, we determined that G. buenoi in clade 11 evolved under the pressure of positive selection, with the evolutionary sites of A at position 214 and T at position 451, thus clarifying the differences in amino acids among species and providing a better understanding of the molecular evolutionary mechanism of Hemipteran FAR. In addition, structural analysis of the FAR genes revealed duplication of the two conservative domains, the Rossmann‐fold domain and the sterile domain, of the FAR in four species, namely Bemisia tabaci, Diaphorina citri, R. prolixus and Trialeurodes vaporariorum. This study lays a foundation for further studies on the molecular functions of Hemiptera FAR, and provides a possible new target for the control of Hemiptera, especially the stink bugs.

Diversity of anamorphic Cordyceps (formerly Isaria) isolated from Brazilian agricultural sites

A total of 53 anamorphic strains of Brazilian Cordyceps species currently maintained in a government-owned culture collection, were reassessed for diversity and species identity using multi-loci-based phylogenetic methods. The strains used in this study were originally obtained from soil samples or were isolated from insects of the orders Hemiptera, Lepidoptera, Coleoptera and Diptera, mostly from agricultural sites. A Bayesian phylogenetic tree was constructed based on a concatenation of five loci (ITS, LSU, RPB1, RPB2 and TEF). In a few cases of ambiguity, morphological traits were also considered for species delimitations. Considerable variability within the set of strains was detected and six Cordyceps species were identified: C. amoenerosea, C. fumosorosea, C. javanica, C. tenuipes and, for the first time, C. brevistroma and C. spegazzinii are reported in Brazil. Four other taxonomically equivocal groups, closely related to other known taxa (C. amoenerosea, C. cateniannulata, C. polyarthra and C. spegazzinii), were also recognized, although further studies will be required to confirm their identifications or their descriptions as new species. Cordyceps javanica was the most common species in our dataset, originally isolated from soil and several different insect orders, and includes 17 strains from the whitefly, Bemisia tabaci. Interestingly, strains previously identified as C. fumosorosea based on morphology and growth characteristics, were shown to be C. javanica, including the active ingredients of some commercial mycoinsecticides. Cordyceps farinosa, usually mentioned in the literature as occurring in Brazil, was not found in our study. Since most strains were from insect crop pests, further studies with hosts from non-agricultural settings or from environmental samples would be advisable for a deeper understanding of the occurrence of anamorphic Cordyceps in Brazil.

Diversity and Abundance of Aquatic Insect Fauna in an Urban Freshwater Lake, Hatirjheel, Dhaka, Bangladesh

Freshwater lakes are a crucial component of the urban ecology and offer several direct and indirect advantages to its people. Habitat degradation of native insects has happened because of development activities and unscientific natural resource management. As a consequence, many insects of freshwater lakes are now rare and endangered. A research was conducted to find out the abundance, variety and distribution of aquatic insect fauna in an urban freshwater lake, Hatirjheel, Dhaka during November 2015 to February 2016. A total of 3255 individuals of water insects comprising of 11 species and 31 genera under 20 families belonging 5 orders were recorded. The order Hemiptera contained the highest abundance (38.71%) including 7 families and 12 genera containing 5 species, while Trichoptera had the lowest (6.45%) including 2 families and 2 genera. The dominating species in the lake was Micronecta haliploides. The maximum 19 aquatic insect species were reported in the lake's vegetation-rich section near the Mouchak-Moghbazar flyover (Spot 1), whereas a minimum of 5 species were found near the Modhubagh bridge road (Spot 2). Species diversity index (H′ = 2.74), species richness (SR = 8.54), aquatic insect distribution evenness (J′ = 0.80), community dominance (CD = 46.94%), and Simpson’s index (λ = 0.17) were analyzed in this study to determine the diversity, abundance, distribution and dominance of aquatic insect fauna in this lake. Bangladesh J. Zool. 50(3): 363-372, 2022

Wing Dimorphism/polymorphism in True Bugs (Heteroptera) From a Functional Viewpoint: A review

In this review article the available information on the wing dimorphism/polymorphism occurring at non-phytophagous Heteroptera is reviewed from a functional viewpoint. This meant practically the information about the wing dimorphism/polymorphism of the superfamily Gerroidea, as hardly anything has been published on this theme of other non-phytophagous Heteroptera. Seasonal and concurrent wing dimorphism/polymorphism are treated and discussed separately. Heritability and phenotypical plasticity of the wing form, and the effects of different modifying environmental factors are briefly reviewed and discussed. The superior reproductive ability of the non-macropterous form is well documented at female gerroid bugs; there are less available data on the males. The seasonal wing polymorphism directed by photoperiod and affected by temperature is usually well adapted to the current environmental conditions. The effects of the population density and that of the food quantity and quality on wing form of the gerroid bugs have not been well understood yet; and it is arguable, whether the macropterous/non macropterous ratio of the natural gerroid populations corresponds to the temporal stability of their actual habitats in an adaptive way. Wing dimorphism/polymorphism has to be evaluated within the wider concept of dispersal polymorphism, which includes other related phenomena like wing muscle polymorphism and behavioural differences.

Diversity of True Bugs (Hemiptera: Heteroptera) on Common Ragweed (Ambrosia artemisiifolia) in Southern Slovakia

The common ragweed (Ambrosia artemisiifolia Linnaeus 1800) is an exceptionally invasive species. The information on true bugs occurring on ragweed plants is limited in the invasion region. The objective of this study was to determine the species composition of Heteroptera associated with A. artemisiifolia, to assess their vectoring potential based on a literature review, and to compare species similarity in the surveyed fields. Field surveys were conducted in 2020–2021 at 10 sites in southern Slovakia. Sweeping and visual observations were conducted in field margins, weedy agricultural fields, and mowed meadows infested with A. artemisiifolia. In the study, food specialization, the abundance of individual species, and their assignment to families were precisely determined. The Jaccard similarity index was used to evaluate similarities in species composition among the sites studied. A total of 2496 true bugs were recorded, representing 47 species of Heteroptera from 12 families. The most common phytophagous species were Nysius ericae ericae (Schilling, 1829) (Pentatomomorpha, Lygaeidae), Adelphocoris lineolatus (Goeze, 1778), Lygus rugulipennis (Poppius, 1911), Lygus pratensis (Linnaeus, 1758) (Cimicomorpha, Miridae), and a zoophagous species Nabis (Dolichonabis) limbatus (Dahlbom, 1851) (Cimicomorpha, Nabidae). The species similarities in pair-wise combined localities were low, with a dominance of highly migratory and polyphagous species able to traverse the field from the adjacent landscape. A. artemisiifolia is a known host for plant viruses and phytoplasmas, and several Heteroptera species are carriers of these plant pathogens. Halyomorpha halys was the only detected vector of phytoplasmas, and its abundance on A. artemisiifolia was extremely low.