Chrysomelidae Research Articles

Gut bacteria facilitate leaf beetles in adapting to dietary specialization by enhancing larval fitness

Dietary specialization between insect stages can reduce intraspecific food competition. The involvement of gut bacteria and the mechanisms underlying this phenomenon received limited attention. Plagiodera versicolora is a pest harming Salicaceae trees. Here, we confirmed dietary specialization in P. versicolora, wherein adults prefer new leaves, while larvae predominantly consume mature leaves when both types are available. We demonstrated the larval preference for mature leaves confers ecological advantages by promoting growth, development and immunity and this advantage is contingent upon the presence of gut bacteria. Gut microbiota in larvae revealed a significant enrichment of Pantoea when feeding new leaves, with P. anthophila exhibiting the most pronounced inhibitory effect on larval development. Further exploration identified specific metabolites, such as Tyrosyl-valine, with higher content in new leaves, which serve as substrates for the entomopathogenic gut bacterium to facilitate its proliferation. This study provides a fresh perspective on the ecological role of gut bacteria.

The genome sequence of the willow leaf beetle, Lochmaea capreae Linnaeus, 1758.

We present a genome assembly from an individual female Lochmaea capreae (the willow leaf beetle; Arthropoda; Insecta; Coleoptera; Chrysomelidae). The genome sequence is 534.7 megabases in span. Most of the assembly is scaffolded into 17 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 18.85 kilobases in length. Gene annotation of this assembly on Ensembl identified 12,254 protein coding genes.

Evaluating locally sourced inert dusts as insecticides against the cereal leaf beetle ( Oulema melanopus [L.]; Coleoptera: Chrysomelidae): a combined laboratory and field study

Evaluating locally sourced inert dusts as insecticides against the cereal leaf beetle ( <i>Oulema melanopus</i> [L.]; Coleoptera: Chrysomelidae): a combined laboratory and field study

Trap cropping for insect pests in the Canadian Prairies: a review and a case study

AbstractThe Canadian Prairies are one of the major agricultural regions of the world in terms of cereal, oilseed and pulse crop production. With few exceptions, major insect pests like grasshoppers, flea beetles, Lygus bugs, wireworms and pea leaf weevils are controlled with insecticides. Wheat stem sawfly is managed through host plant resistance and endemic natural enemies, whereas cereal leaf beetle is managed through classical biological control. Large farms and short growing seasons in the region present logistical challenges to adopt time intensive pest management systems such as trap crops. Therefore, there is no adoption of trap crops even though some research has demonstrated their potential. In this article we present a brief overview of the pest status and management, and we summarize research on trap crops in the Prairies Ecozone and adjacent ecoregions. We conclude the review with some innovative research ideas to make trap cropping a more appealing pest management system in our quest to reduce dependency on chemical insecticides and increase the environmental resilience of Canadian agroecosystems.

The genome sequence of a leaf beetle, Galeruca laticollis Sahlberg, C.R., 1838

We present a genome assembly from an individual leaf beetle, Galeruca laticollis (Arthropoda; Insecta; Coleoptera; Chrysomelidae). The genome sequence has a total length of 2,154.60 megabases. Most of the assembly (99.92%) is scaffolded into 12 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 19.98 kilobases in length. Gene annotation of this assembly on Ensembl identified 32,229 protein-coding genes.

A new record of Platyphora flavozonata (Blanchard, 1843) (Chrysomelidae: Chrysomelinae) in the Parque Estadual Altamiro de Moura Pacheco, a Cerrado remnant

The Cerrado biome is a vast ecoregion of tropical savanna in eastern Brazil. The leaf beetle species Platyphora flavozonata (Blanchard, 1843) is a new record for Parque Estadual Altamiro de Moura Pacheco in the Cerrado biome. Distribution of record of the species, the high-resolution photos and notes on external morphology are provided.

Morphology and taxonomic significance of the labrum in the flea beetle genus Chaetocnema Stephens, 1831 (Coleoptera, Chrysomelidae, Galerucinae, Alticini)

The structure of labrum or upper lip in adult Coleoptera is only minimally investigated and used in classification and phylogeny. This study investigates the morphology of the labrum in the flea beetle genus Chaetocnema Stephens, 1831 (Chrysomelidae, Galerucinae, Alticini) to assess and develop a terminology and identify potential morphological characters useful to delimitation of species and species groups as well as phylogeny reconstruction in leaf beetles.

Functional characterization of prenyltransferases involved in de novo synthesis of isoprenoids in the leaf beetle Monolepta hieroglyphica

Prenyltransferases play a pivotal role in the isoprenoid biosynthesis and transfer in insects. In the current study, two classes of prenyltransferases (MhieFPPS1 and MhieFPPS2, MhiePFT-β and MhiePF/GGT-α) were identified in the leaf beetle, Monolepta hieroglyphica. Phylogenetic analysis revealed that MhieFPPS1, MhieFPPS2, MhiePFT-β and MhiePF/GGT-α were clustered in one clade with homologous in insects. Moreover, MhieFPPS2 lacked one aspartate-rich motif SARM. Molecular docking and kinetic analysis indicated that the (E)-GPP displayed higher affinity with MhieFPPS1 compared to DMAPP within the binding pocket containing metal binding sites (MG). The other class of prenyltransferases (MhiePFT-β and MhiePF/GGT-α) lack the aspartate-rich motif. Docking results indicated that binding site of MhiePFT-β involved divalent metal ions (Zn) and bound farnesyl or geranylgeranyl. In vitro, only recombiant MhieFPPS1 could catalyze the formation of (E)-farnesol against different combination of substrates, including IPP/DMAPP and IPP/(E)-GPP, highlighting the importance of SARM for enzyme activities. Kinetic analysis further indicated that MhiePFT-β operated via Zn2+-dependent substrate binding, while MhiePF/GGT-α stabilized the β-subunit during catalytic reaction. These findings contribute to a valuable insight in to understanding of the mechanisms involved in the biosynthesis and delivery of isoprenoid products in beetles.

Enrichment of novel entomopathogenic Pseudomonas species enhances willow resistance to leaf beetles

BackgroundPlants have evolved various defense mechanisms against insect herbivores, including the formation of physical barriers, the synthesis of toxic metabolites, and the activation of phytohormone responses. Although plant-associated microbiota influence plant growth and health, whether they play a role in plant defense against insect pests in natural ecosystems is unknown.ResultsHere, we show that leaves of beetle-damaged weeping willow (Salix babylonica) trees are more resistant to the leaf beetle Plagiodera versicolora (Coleoptera) than those of undamaged leaves. Bacterial community transplantation experiments demonstrated that plant-associated microbiota from the beetle-damaged willow contribute to the resistance of the beetle-damaged willow to P. versicolora. Analysis of the composition and abundance of the microbiome revealed that Pseudomonas spp. is significantly enriched in the phyllosphere, roots, and rhizosphere soil of beetle-damaged willows relative to undamaged willows. From a total of 49 Pseudomonas strains isolated from willows and rhizosphere soil, we identified seven novel Pseudomonas strains that are toxic to P. versicolora. Moreover, re-inoculation of a synthetic microbial community (SynCom) with these Pseudomonas strains enhances willow resistance to P. versicolora.ConclusionsCollectively, our data reveal that willows can exploit specific entomopathogenic bacteria to enhance defense against P. versicolora, suggesting that there is a complex interplay among plants, insects, and plant-associated microbiota in natural ecosystems.Graphical 5putw3esi-W9k4EYdexs12Video

Dynamic trends in maize diseases and pests across six regions in China over two decades

Maize production faces persistent threats from maize diseases and pests (MDPs) throughout its growth cycle, posing substantial risks to food security. However, understanding the spatio-temporal dynamics of MDPs occurrences on a regional scale has remained elusive due to a lack of continuous observation data. This study curated a comprehensive dataset spanning two decades, from 1999 to 2018, across six key maize planting regions in China [Spring sown area in Northern China (1-NC), Summer sown region in Huang-Huai-Hai Plain (2-HHP), Southwest Mountain Maize Region (3-SM), Southern Hilly Maize Region (4-SH), Northwest Irrigated Maize Region (5-NI), and Maize Region in Qinghai-Tibet Plateau (6-QTP)]. The average extent of MDP occurrence in 1-NC and 2-HHP exceeded that in other regions over the two-decade period. Furthermore, the occurrence of MDPs exhibited a substantial increase in 1-NC, 2-HHP, 3-SM, 4-SH, and 5-NI over the same period. Meanwhile, the average occurrence intensity of MDPs in 2-HHP surpassed that in other regions. Notably, maize leaf blight and the Asian maize borer emerged as predominant diseases and pests in 1-NC, 2-HHP, 3-SM, 4-SH, and 5-NI. A bivariate trend analyses highlighted a notable increase in the species count for both the extent and intensity of MDP occurrences, including double-spotted leaf beetle in 1-NC, and cotton bollworm in 2-HHP. This extensive, long-term analysis offers a foundation for devising comprehensive strategies for MDP control on a national scale, enabling the formulation of tailored forecasting and control measures across six planting regions.

Genetic Characterization of Two Novel Insect-Infecting Negative-Sense RNA Viruses Identified in a Leaf Beetle, Aulacophora indica.

Herbivorous insects harbor a variety of insect-specific viruses (ISVs) some of which are considered to be valuable biological agents for potential applications in biological defense and control strategies. Leaf beetles with chewing mouthparts are particularly known for their capacity to disrupt plant tissue while feeding, often creating openings that can act as entry points for plant pathogens. In this study, we have identified two new negative-sense RNA viruses infecting the leaf beetle Aulacophora indica, an important member of the Chrysomelidae family. These recently discovered viruses belong to the viral families Nyamiviridae and Chuviridae and have been preliminarily named Aulacophora indica nyami-like virus 1 (AINlV1) and Aulacophora indica chu-like virus 1 (AIClV1), respectively. The complete genomic sequences of these viruses were obtained using rapid amplification of cDNA ends (RACE) techniques. Detailed analysis of their genomic structures has confirmed their similarity to other members within their respective families. Furthermore, analysis of virus-derived small interfering RNA (vsiRNA) demonstrated a high abundance and typical vsiRNA pattern of AINlV1 and AIClV1, offering substantial evidence to support their classification as ISVs. This research enhances our understanding of viral diversity within insects.

Cereal leaf beetle (Oulema spp.) damage reduces yield and is more severe when natural enemy action is prevented

Insect pests pose a global threat to crop yield. Biological control by natural enemies aims to reduce pest damage in a sustainable way. Cereal leaf beetles (CLB; Oulema spp.) are major pests in small-grain cereals. We studied the effect of natural enemies on CLB damage and its consequences on yield within its native distribution area in Europe. In exclusion cage experiments and by documenting a naturally occurring CLB damage gradient, we found that CLB damage reduced yield, but natural enemy action reduced the damage by CLB. Comparing exclusion and open treatments on artificially CLB-infested plants, plants accessible to natural enemies had 30% less leaf damage. CLB damage significantly affected yield parameters. Thousand grain weight was 22–29% less in maximum leaf damage scenarios. In the damage gradient field, maximal infestation reduced grain yield by 52%. However, maximal damage occurred only on a few plants and over small areas. In natural infestation cases, the number of CLB larvae per plant had a median of zero; nevertheless, there were more than 35 larvae on 10% of the plants. Patchiness explained 40% of CLB damage variance. Damage was unevenly distributed; as a result, thousand grain weight decreased only by 1.6% for 75% of the plants but by 18% for 10% of the plants. In the natural damage gradient, the estimated yield loss for the entire field was 16% due to CLB. Skewed CLB distribution may lead to perceptible yield losses locally, but natural enemies may limit overall damage to the crop.

The genome sequence of a leaf beetle, Chrysolina haemoptera (Linnaeus, 1758)

We present a genome assembly from a female leaf beetle, Chrysolina haemoptera (Arthropoda; Insecta; Coleoptera; Chrysomelidae). The total length of the genome sequence is 718.30 megabases. Most of the assembly is scaffolded into 20 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 17.87 kilobases long. Gene annotation of this assembly on Ensembl identified 12,298 protein-coding genes.

Harmfulness and biological characters of a leaf beetle Gastrolina depressa (Coleoptera: Chrysomelidae) to its host plant Pterocarya stenoptera (Fagales: Juglandaceae)

Gastrolina depressa (Coleoptera: Chrysomelidae) has been found to damage many walnut plants in China. It prefers to feed on the annual leaves of an important economic plant, Pterocarya stenoptera (Fagales: Juglandaceae), and causes extensive cosmetic destruction, even plant death. Nevertheless, its biological characteristics are mostly unknown. In this study, we investigate the harmful and biological characteristics of G. depressa with different developmental stages. The results showed that G. depressa had four developmental stages: egg, larva (1st -3rd instar), pupa, and adult, the life history lasted nine days, with obvious overlapping generations. The food intake of the larvae increased with the increase of the instar, and the maximum food intake of the 3rd instar larvae was 448.19 mm2. The abdomen of the females was enlarged before oviposition, and the average number of eggs laid was 47.63 ± 13.53. Bioassay showed that there was no difference in the search time for the young (2.03, 1.25, 1.15, and 0.91 min) and old leaves (1.68, 1.15, 0.90, and 1.93 min) of P. stenoptera between 1st -3rd instar larvae and adults; the feeding preference of 1st -3rd instar larvae and adults for young leaves was higher than that to old leaves (23.33%, 26.67%, 33.33%, and 21.67%, respectively). The successful selection rates of 1st -3rd instar larvae and adults to young leaves (81.67%, 80%, 85.00%, and 70.00%, respectively) was higher than to old leaves (8.35%, 11.67%, 3.34%, and 11.67%, respectively).

Leaf beetle Phyllotreta striolata (Coleoptera: Chrysomelidae): Biology and infestation on Chinese flowering cabbage Brassica rapa var. parachinensis in Bogor, West Java, Indonesia

Abstract. Laia DAS, Maryana N, Winasa IW. 2024. Leaf beetle Phyllotreta striolata (Coleoptera: Chrysomelidae): Biology and infestation on Chinese flowering cabbage Brassica rapa var. parachinensis in Bogor, West Java, Indonesia. Biodiversitas 25: 3099-3105. Chinese flowering cabbage (Brassica rapa var. parachinensis L.) holds significant economic value and provides essential nutrition. Bogor District, a primary region for vegetable production in Indonesia, faces a severe issue due to the leaf beetle Phyllotreta striolata Fabricius 1803 infestation on Chinese flowering cabbage plants. However, research on this pest in Indonesia is still limited. Observations on the biological aspects of P. striolata involved collecting and identifying adult P. striolata from Chinese flowering cabbage fields, along with biological observations focusing on the beetle's morphology and developmental stages. Population calculations of adult beetles and evaluation of P. striolata infestation intensity on Chinese flowering cabbage plants were conducted in four sub-districts in Bogor District. The average life cycle of this beetle was 27.15 days. The study revealed that the adult stage lasted an average of 119.10 days, with an average preoviposition period of 3.08 days. Adult populations tended to decrease with the age of Chinese flowering cabbage plants due to environmental factors and food source availability. Infestation intensity varied across locations, with Leuwimalang showing the lowest intensity (23.56%) and Laladon the highest (48.76%). These differences suggest that the environment in Leuwimalang may support the resistance of Chinese flowering cabbage plants to leaf pest attacks.

Drought stress enhances plastid-mediated RNA interference for efficient the willow leaf beetle management

Plastid-mediated RNA interference has emerged as a promising and effective approach for pest management. By expressing high levels of double-stranded RNAs (dsRNAs) in plastid that target essential pest genes, it has been demonstrated to effectively control certain herbivorous beetles and spider mites. However, as plants are sessile organisms, they frequently experience a combination of biotic and abiotic stresses. It remains unclear whether abiotic stress, such as drought stress, influences the accumulation of dsRNAs produced in plastids and its effectiveness in controlling pests. In this study, we aimed to investigate the effects of drought stress on dsACT expression in transplastomic poplar plants and its control efficiency against the willow leaf beetle (Plagiodera versicolora). Our findings revealed that drought stress did not significantly affect the dsRNA contents in transplastomic poplar plants, but it did lead to higher mortality of insect larvae. This increased mortality may be attributed to increased levels of jasmonic acid and cysteine proteinase inhibitor induced by water deficit. These results contribute to understanding of the mechanisms linking water deficit in plants to insect performance and provide valuable insights for implementing appropriate pest control strategies under drought stress conditions.

The genome sequence of the Cow Parsley Leaf Beetle, Chrysolina oricalcia (O.F. Müller, 1776).

We present a genome assembly from an individual Cow Parsley Leaf Beetle Chrysolina oricalcia (the Cow Parsley Leaf Beetle; Arthropoda; Insecta; Coleoptera; Chrysomelidae). The genome sequence is 1,423.4 megabases in span. Most of the assembly is scaffolded into 22 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 16.93 kilobases in length. Gene annotation of this assembly on Ensembl identified 35,990 protein coding genes.

Insecticidal Triterpenes in Meliaceae III: Plant Species, Molecules, and Activities in Munronia-Xylocarpus.

Plants of the Meliaceae family have long attracted researchers' interest due to their various insecticidal activities, with triterpenes being the main active ingredients. In this paper, we discuss 93 triterpenoids with insecticidal activity from 37 insecticidal plant species of 15 genera (Munronia, Neobeguea, Pseudocedrela, Nymania, Quivisia, Ruagea, Dysoxylum, Soymida, Lansium, Sandoricum, Walsura, Trichilia, Swietenia, Turraea, and Xylocarpus) in the family Meliaceae. Among these genera, Trichilia deserves further research, with twelve species possessing insecticidal activity. The 93 insecticidal molecules included 27 ring-seco limonoids (comprising 1 ring A-seco group chemical, 1 ring B-seco group chemical, 5 ring D-seco group chemicals, 14 rings A,B-seco group chemicals, 5 rings B,D-seco group chemicals, and 1 rings A,B,D-seco group chemical), 22 ring-intact limonoids (comprising 5 cedrelone-class chemicals, 6 trichilin-class chemicals, 7 havanensin-class chemicals, 2 azadirone-class chemicals, 1 vilasinin-class chemical, and 1 other chemical), 33 2,30-linkage chemicals (comprising 25 mexicanolide-class chemicals and 8 phragmalin-class chemicals), 3 1,n-linkage-group chemicals, 3 onoceranoid-type triterpenoids, 2 apotirucallane-type terpenoids, 2 kokosanolide-type tetranortriterpenoids, and 1 cycloartane triterpene. In particular, 59 molecules showed antifeedant activity, 30 molecules exhibited poisonous effects, and 9 molecules possessed growth regulatory activity. Particularly, khayasin, beddomei lactone, 3β,24,25-trihydroxycycloartane, humilinolides A-E and methyl-2-hydroxy-3β-isobutyroxy-1-oxomeliac-8(30)-enate showed excellent insecticidal activities, which were comparable to that of azadirachtin and thus deserved more attention. Moreover, it was noteworthy that various chemicals (such as 12α-diacetoxywalsuranolide, 11β,12α-diacetoxycedrelone, 1α,7α,12α-triacetoxy-4α-carbomethoxy-11β-hydroxy-14β,15β-epoxyhavanensin, and 11-epi-21-hydroxytoonacilide, etc.) from Turraea showed excellent insecticidal activity. Specially, the insecticidal activity of khayasin from Neobeguea against the coconut leaf beetle were similar to that of rotenone. Therefore, it was a promising candidate insecticide for the control of the coconut leaf beetle.

Development of parasite complexes in the ecosystem of the rose garden of the main Botanical Garden of the Russian Academy of Sciences

The article reports on studies (2011-2022) monitoring harmful organisms in the ecosystem of the rose garden of the Main Botanical Garden of the Russian Academy of Sciences. The studies yielded data on the detection of pathogens and pests, as well as the phenotypic manifestation of pathologies and lesions. A total of 21 species of pathogens and 16 species of phytophages were identified. The species composition of harmful organisms in the ecosystem of the rose garden was defined. It is shown that at the initial stage (2011- 2013) of ecosystem establishment, no external signs of viral diseases were observed, and a low level of fungal infections was noted. The development of such harmful pathogens as Peronospora sparsa Jacz., Sphaerotheca pannosa Lev., Phragmidium disciflorum James, and Ph. tuberculatum Mull. was controlled by culling plants of susceptible varieties. The predominant pathogens included Marssonina rosae (Lib.) Died., Phyllosticta rosae Desm., and Septoria rosae Desm., and the susceptibility of specific varieties to these pathogens was established. The populations of pathogens causing spot anthracnose (Sphaceloma rosarum Pass.), ascochyta leaf spot (Ascochyta rosicola Sacc.), and cercospora leaf spot (Cercospora rosicola Pass.) were slightly less common. A wide range of signs of viral infections was identified. Nine viruses belonging to five genera were detected. The frequency of their occurrence was analyzed, and the most common viruses were identified: Prunus necrotic ring spot ilarvirus, Apple mosaic ilarvirus, Tobacco ring spot nepovirus, and Arabis mosaic nepovirus. The species diversity of phytophages was noted: leaf beetles, snout beetles, leafroller moths, sawflies, blossom weevils, earwigs, moths, leafhoppers, aphids, and true bugs. It was found that damage to plants by a range of pests reached only an average level, except for individual varieties (Red Blanket and Prosperity). In general, the phytosanitary assessment of the rose gene pool of the garden according to the phytosanitary monitoring and integrated detection revealed a wide range of parasite complexes: fourteen types of pathogenic complexes, four types of entomological complexes, and five types of entomopathogenic complexes. The tactical and basic directions for control of harmful organisms in the ecosystem of the rose garden are discussed.

Feeding Preferences of the Bean Leaf Beetle (Ootheca spp.) (Coleoptera: Chrysomelidae): Insights for Targeted Pest Control Strategies in Uganda.

The bean leaf beetle (BLB) (Ootheca spp.) is a polyphagous pest causing significant yield losses in Uganda, particularly in the Northern and Eastern regions on various hosts plants. Despite its polyphagous behaviour, the BLB exhibits preferential feeding, offering an opportunity for targeted pest management. This study explored its feeding preferences across seven crops: common bean, cowpea, greengram, okra, roselle (malakwang), groundnuts, and soybean. This study was conducted in Arua and Lira districts using a randomized complete block design for two rainy seasons (2018A and 2018B). The results showed significant differences in BLB abundance and foliar damage among host crops, locations, days after planting and seasons. Cowpea was the most preferred crop while groundnuts was the least preferred. Therefore, cowpea can be recommended for use as a trap for managing Ootheca spp. in gardens where it is not the main crop. There was a higher pest abundance in Arua than in Lira. There was also a higher pest abundance in 2018A than in 2018B. These findings highlight the importance of understanding BLB's feeding preferences for implementing effective IPM strategies, emphasizing the potential role of trap cropping, especially with cowpea, to minimize BLB damage in resource-constrained agricultural settings.