Colorado Potato Beetle Leptinotarsa Decemlineata Research Articles

SPREADING OF COLORADO POTATO BEETLE RESISTANCE TO CHEMICAL INSECTICIDES IN SIBERIA AND HISTORY OF ITS SETTLING IN THE SECONDARY AREA

Data obtained from toxicological analysis of sensitivity to insecticides in Colorado potato beetle Leptinotarsa decemlineata Say (Coleoptera, Chrysomelidae) in Novosibirsk region evidenced presence of multiresistance to organophosphorus compounds (OPC), neonicotinoids and nereistoxins. High level of sensibility to pyrethroids and phenylpyrazoles is a peculiarity of Novosibirsk population of Colorado beetle. These data as well as high phenotypical similarity of adults from Novosibirsk region and Kazakhstan suggest that population complex of Colorado beetle in Kazakhstan had formed from part of the “settling wave” which did not fall under wide-scale pyrethroids application in the middle zone of Russia in 1980th. Probably,further spreading of this part of Kazakhstan population northwards led to formationof new zones of species naturalization in Siberia.

A Day in the Life: Identification of Developmentally Regulated MicroRNAs in the Colorado Potato Beetle (Leptinotarsa decemlineata; Coleoptera: Chrysomelidae).

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an important pest of the cultivated potato (Solanum tuberosum (L.) [Solanales: Solanaceae]). With its broad resistance toward commonly used insecticides, it is clear that more sophisticated control strategies are needed. Due to their importance in insect development, microRNAs (miRNAs) represent a potential tool to employ in insect control strategies. However, most studies conducted in this area have focused on model species with well-annotated genomes. In this study, next-generation sequencing was used to catalogue the miRNAs produced by L. decemlineata across all eight stages of its development, from eggs to adults. For most stages, the length of miRNAs peaked between 21 and 22 nt, though it was considerably longer for the egg stage (26 nt). Global profiling of miRNAs revealed three distinct developmental clusters: 1) egg stage; 2) early stage (first, second, and third instar); and 3) late stage (fourth instar, prepupae, pupae, and adult). We identified 86 conserved miRNAs and 33 bonafide novel miRNAs, including stage-specific miRNAs and those not previously identified in L. decemlineata. Most of the conserved miRNAs were found in multiple developmental stages, whereas the novel miRNAs were often stage specific with the bulk identified in the egg stage. The identified miRNAs have a myriad of putative functions, including growth, reproduction, and insecticide resistance. We discuss the putative roles of some of the most notable miRNAs in the regulation of L. decemlineata development, as well as the potential applications of this research in Colorado potato beetle management.

Glyphosate-based herbicide affects the composition of microbes associated with Colorado potato beetle (Leptinotarsa decemlineata).

Here, we examined whether glyphosate affects the microbiota of herbivores feeding on non-target plants. Colorado potato beetles (Leptinotarsa decemlineata) were reared on potato plants grown in pots containing untreated soil or soil treated with glyphosate-based herbicide (GBH). As per the manufacturer's safety recommendations, the GBH soil treatments were done 2 weeks prior to planting the potatoes. Later, 2-day-old larvae were introduced to the potato plants and then collected in two phases: fourth instar larvae and adults. The larvae's internal microbiota and the adults' intestinal microbiota were examined by 16S rRNA gene sequencing. The beetles' microbial composition was affected by the GBH treatment and the differences in microbial composition between the control and insects exposed to GBH were more pronounced in the adults. The GBH treatment increased the relative abundance of Agrobacterium in the larvae and the adults. This effect may be related to the tolerance of some Agrobacterium species to glyphosate or to glyphosate-mediated changes in potato plants. On the other hand, the relative abundances of Enterobacteriaceae, Rhodobacter, Rhizobium and Acidovorax in the adult beetles and Ochrobactrum in the larvae were reduced in GBH treatment. These results demonstrate that glyphosate can impact microbial communities associated with herbivores feeding on non-target crop plants.

Genetic structure of the invasive Colorado potato beetle Leptinotarsa decemlineata populations in China

The Colorado potato beetle (CPB), Leptinotarsa decemlineata Say, is an infamous invasive species worldwide. It was first found in Xinjiang Uygur Autonomous Region of China in 1993 and spread to Northeast China in 2013. To better understand the genetic structure and the diffusion path of their populations in China, we used nine polymorphic microsatellite loci to elucidate the genetic diversity, genetic structure and gene flow among nine CPB populations across Xinjiang and Northeast China. The results show that: (1) Two genetically separated clusters were identified by phylogenetic tree, principal coordinate analysis (PCoA) and Bayesian cluster method. Cluster one contained populations from Xinjiang, China. Cluster two contained populations from Northeast China. A genetic differentiation existed between the two clusters. (2) Three populations in Northeast China hold an obvious genetic differentiation according to the phylogenetic tree and PCoA, indicating that multiple introductions may occur in Northeast China. (3) The Altay population in Xinjiang showed a closer genetic relationship with the populations in Northeast China which may be due to the fact that they collectively originated in neighboring Russia. (4) Among all populations, Mulei and Wusu had obvious gene migrations from Tacheng, indicating that the inland populations are most likely to originate from Tacheng, Xinjiang.

Insect predator odors protect herbivore from fungal infection

Lethal predators and pathogens can reduce the size of pest populations and help regulate crop-damaging herbivores. Additionally, predators like the spined soldier bug (Podisus maculiventris) can elicit non-consumptive effects in herbivores such as the Colorado potato beetle (Leptinotarsa decemlineata), causing changes in prey behavior, physiology and life history. While it is known that lethal predators and pathogens interact, there is little known about the interaction of predator-induced non-consumptive effects and pathogens on their shared hosts. Using the spined soldier bug, which is known to elicit non-consumptive effects on potato beetles (e.g. reduced feeding), we studied the interaction of predator-induced non-consumptive effects and the fungal pathogen Beauveria bassiana on the survival of Colorado potato beetle larvae. In laboratory microcosms we found a 16–50% increase in survival of fungus-treated beetles held with non-lethal male stink bugs. We also studied the predator-fungus interaction on jasmonic acid-treated plants to assess whether elevated levels of host plant defenses made larvae more susceptible to fungal infection. Beetles’ susceptibility to fungal infection did not change when provided jasmonic-acid treated foliage as food. Finally, we determined that two volatile compounds (E-2-hexenal and alpha-terpineol), produced as part of the bugs’ aggregation pheromone, reduced conidial germination, resulting in higher levels of beetle survival. Our findings suggest that stink bug odors protect prey against fungal pathogens.

Effect of two neem-derived pesticides on Colorado potato beetle (Leptinotarsa decemlineata Say) (Coleoptera: Chrysomelidae) under laboratory conditions

Mortality and antifeedant activity of two different neem-derived pesticides were investigated on larvae of Colorado potato beetle (Leptinotarsa decemlineata Say). In no-choice tests, mortality of larvae in- creased with increase in time period, meanwhile the feeding damage decreased with the increase of neem leaf extract concentration in contrast to NeemAzal T/S (1% azadirachtin) in which neither there was any signifi- cant difference in mortality nor on feeding damage. In the choice test, none of the treatments were lethal to the larvae tested. The larvae fed on the leaves irrespective of the treatment.

Potential of Colorado Potato Beetle (Coleoptera: Chrysomelidae) to Adapt to Alternative Host Plants.

Twelve selected cultivated or wild solanaceae (Solanum dulcamara, Solanum nigrum, Solanum villosum, Solanum lycopersicum, Solanum muricatum, Solanum melongena, Datura innoxia, Datura metel, Physalis spp., Capsicum annuum, Nicotiana alata, and Petunia spp.) (all species Solanales: Solanaceae) were tested as potential alternative host plants against Solanum tuberosum for a local population of the Colorado potato beetle Leptinotarsa decemlineata Say (CPB) in Estonia. Some CPB populations in America and southern Europe accept most of these plants. However, geographically isolated populations of beetles can differ in their acceptance of new host plants. Migrants from the southern Europe supplement Estonian beetle population regularly, so individuals may differ in their host plant preferences. S. melongena and S. dulcamara were well accepted by the beetles, Lycopersicum spp. (Solanales: Solanaceae) and N. alata were intermediate, and S. villosum and S. nigrum were least accepted. The beetles rejected S. muricatum, Physalis spp., C. annuum, Petunia spp., and D. metel. First-instar larvae completed a full life cycle only on S. dulcamara, N. alata, S. lycopesicum, S. melongena, although their development rate was slower, mortality was higher and emerging adults were underweight relative to those that fed on S. tuberosum. The fourth-instar larvae were less sensitive in relation to food. We found that S. dulcamara as a native plant could provide resources for CPB during early and late season. At the same time, the cultivated S. melongena would be suitable plant species for further testing as dead-end crop for integrated pest management.

Silencing downstream of receptor kinase gene (drk) impairs larval-pupal ecdysis in Leptinotarsa decemlineata (Say)

Abstract In insects, an insulin-like peptide (ILP) triggers the formation of the insulin receptor (InR)/the insulin receptor substrate Chico complex. The complex then recruits downstream of receptor kinase (Drk) and phosphatidylinositol-3-kinase (PI3K) to initiate two signaling branches, i.e., Drk-mitogen-activated protein kinase (MAPK) and Pi3K-protein kinase B subdivisions. Previous findings reveal that RNA interference (RNAi) of LdILP2 or Ldchico, rather than Ldpi3k92E, impairs larval-pupal and pupal-adult molting in the Colorado potato beetle Leptinotarsa decemlineata. It is accordingly hypothesized that the Drk-MAPK branch regulates larval metamorphosis. In the present paper, we first found that silencing LdILP2, Ldchico or Ldpi3k92E did not decrease the expression level of Lddrk, indicating other receptor tyrosine kinases’ signaling except insulin pathway is not affected in the RNAi larvae. Moreover, two InRs and Torso were highly expressed in the final larval instars. Furthermore, RNAi of either Lddrk or Ldchico, or both of them equally affected larval-pupal and pupal-adult molts, and similarly repressed the expression of representative MAPK (Ldras and Ldraf), ecdysteroidogenesis (Ldphm and Ldsad), and 20E signaling (LdEcR, LdUSP, LdHR3 and LdE75) genes. 20E feeding by Lddrk RNAi larvae completely restored the reduced mRNA levels of LdEcR, LdHR3 and LdE75, but did not rescued the decreased Lddrk and LdUSP levels and the lowered pupation and emergence rates. Therefore, our findings suggest that the Drk-MAPK branch is involved in metamorphosis regulation in L. decemlineata.

Pathways to defense metabolites and evading fruit bitterness in genus Solanum evolved through 2-oxoglutarate-dependent dioxygenases

The genus Solanum comprises three food crops (potato, tomato, and eggplant), which are consumed on daily basis worldwide and also producers of notorious anti-nutritional steroidal glycoalkaloids (SGAs). Hydroxylated SGAs (i.e. leptinines) serve as precursors for leptines that act as defenses against Colorado Potato Beetle (Leptinotarsa decemlineata Say), an important pest of potato worldwide. However, SGA hydroxylating enzymes remain unknown. Here, we discover that 2-OXOGLUTARATE-DEPENDENT-DIOXYGENASE (2-ODD) enzymes catalyze SGA-hydroxylation across various Solanum species. In contrast to cultivated potato, Solanum chacoense, a widespread wild potato species, has evolved a 2-ODD enzyme leading to the formation of leptinines. Furthermore, we find a related 2-ODD in tomato that catalyzes the hydroxylation of the bitter α-tomatine to hydroxytomatine, the first committed step in the chemical shift towards downstream ripening-associated non-bitter SGAs (e.g. esculeoside A). This 2-ODD enzyme prevents bitterness in ripe tomato fruit consumed today which otherwise would remain unpleasant in taste and more toxic.

Colorado potato beetle microsymbiont Enterobacter BC-8 inhibits defense mechanisms of potato plants using crosstalk between jasmonate- and salicylate-mediated signaling pathways

One of the main insect potato pests is the Colorado potato beetle (Leptinotarsa decemlineata Say). It contains some microbial associates which can affect diverse interactions between host plant and the herbivorous insect. Previously, the most common L. decemlineata microsymbiont isolated from anterior and posterior parts of beetle gut was defined as Enterobacter BC-8. The role of Enterobacter BC-8 in manipulating plant defenses was investigated using antibiotics-treated beetles and model system simulating beetles attacks (wounding plants treated with Enterobacter BC-8 suspension). We demonstrated that the symbiotic bacteria suppressed plant defenses such as hydrogen peroxide and phenolic compounds accumulation and activity of peroxidases and trypsin inhibitors. It is worth noting that the influence of the insect symbionts on potato plants stimulated salicylate-sensitive genes and the marker of salicylate signaling pathway. Transcription activities of jasmonate-sensitive genes which encode some defense proteins against herbivores, were suppressed. So, Enterobacter BC-8 plays the role in salicylate/jasmonate crosstalks manipulating to suppress plant defense mechanisms.

Differential expression of transcripts with potential relevance to chlorantraniliprole response in the Colorado potato beetle, Leptinotarsa decemlineata.

The Colorado potato beetle (Leptinotarsa decemlineata [Say]) is an insect pest that can significantly harm potato plants worldwide. Control of this insect relies heavily on chemical insecticides such as chlorantraniliprole. Nevertheless, the complete molecular signature associated with response to this compound is lacking in L. decemlineata. In this study, amplification and quantification by qRT-PCR (quantitative reverse transcription-polymerase chain reaction) of targets relevant to chlorantraniliprole were undertaken in insects exposed to this chemical. This approach showed modulation of numerous cytochrome P450s, such as CYP350D1 and CYP4Q3, as well as upregulation of microRNAs (miRNAs), including miR-1-3p and miR-305-5p, in chlorantraniliprole-exposed insects. Functional assessment of transcript targets predicted to be regulated by these miRNAs was performed and revealed their likely impact on transcriptional regulation. RNAi-based targeting of CYP350D1 notably provided preliminary evidence of its underlying implication for chlorantraniliprole response in L. decemlineata. Overall, this study strengthens the current knowledge of the molecular changes linked to chlorantraniliprole response in L. decemlineata and provides novel targets with potential relevance to chlorantraniliprole susceptibility in this insect pest of global relevance.

Changes in emergence phenology, fatty acid composition, and xenobiotic-metabolizing enzyme expression is associated with increased insecticide resistance in the Colorado potato beetle.

The Colorado potato beetle (Leptinotarsa decemlineata) is a major agricultural pest of solanaceous crops. An effective management strategy employed by agricultural producers to control this pest species is the use of systemic insecticides. Recent emphasis has been placed on the use of neonicotinoid insecticides. Despite efforts to curb resistance development through integrated pest management approaches, resistance to neonicotinoids in L. decemlineata populations continues to increase. One contributing factor may be alterations in insect fatty acids, which have multiple metabolic functions and are associated with the synthesis of xenobiotic‐metabolizing enzymes to mitigate the effects of insecticide exposure. In this study, we analyzed the fatty acid composition of L. decemlineata populations collected from an organic production field and from a commercially managed field to determine if fatty acid composition varied between the two populations. We demonstrate that a population of L. decemlineata that has a history of systemic neonicotinoid exposure (commercially managed) has a different lipid composition and differential expression of known metabolic detoxification mechanisms relative to a population that has not been exposed to neonicotinoids (organically managed). The fatty acid data indicated an upregulation of Δ6 desaturase in the commercially managed L. decemlineata population and suggest a role for eicosanoids and associated metabolic enzymes as potential modulators of insecticide resistance. We further observed a pattern of delayed emergence within the commercially managed population compared with the organically managed population. Variations in emergence timing together with specific fatty acid regulation may significantly influence the capacity of L. decemlineata to develop insecticide resistance.

Sublethal Pyrethroid Insecticide Exposure Carries Positive Fitness Effects Over Generations in a Pest Insect

Stress tolerance and adaptation to stress are known to facilitate species invasions. Many invasive species are also pests and insecticides are used to control them, which could shape their overall tolerance to stress. It is well-known that heavy insecticide usage leads to selection of resistant genotypes but less is known about potential effects of mild sublethal insecticide usage. We studied whether stressful, sublethal pyrethroid insecticide exposure has within-generational and/or maternal transgenerational effects on fitness-related traits in the Colorado potato beetle (Leptinotarsa decemlineata) and whether maternal insecticide exposure affects insecticide tolerance of offspring. Sublethal insecticide stress exposure had positive within-and transgenerational effects. Insecticide-stressed larvae had higher adult survival and higher adult body mass than those not exposed to stress. Furthermore, offspring whose mothers were exposed to insecticide stress had higher larval and pupal survival and were heavier as adults (only females) than those descending from control mothers. Maternal insecticide stress did not explain differences in lipid content of the offspring. To conclude, stressful insecticide exposure has positive transgenerational fitness effects in the offspring. Therefore, unsuccessful insecticide control of invasive pest species may lead to undesired side effects since survival and higher body mass are known to facilitate population growth and invasion success.

Can Indirect Herbicide Exposure Modify the Response of the Colorado Potato Beetle to an Organophosphate Insecticide?

Organisms live in complex multivariate environments. In agroecosystems, this complexity is often human-induced as pest individuals can be exposed to many xenobiotics simultaneously. Predicting the effects of multiple stressors can be problematic, as two or more stressors can have interactive effects. Our objective was to investigate whether indirect glyphosate-based herbicide (GBH) exposure of the host plant has interactive effects in combination with an insecticide (azinphos-methyl) on an invasive pest Colorado potato beetle (Leptinotarsa decemlineata Say). We tested the effects of GBH and insecticide on the survival, insecticide target genes expression (acetylcholinesterase genes) and oxidative status biomarkers (glutathione S-transferase [GST], glucose-6-phosphate dehydrogenase [G6PDH], glutathione reductase homolog [GR], glutathione peroxidase homolog [GPx], total glutathione [totGSH], glutathione reduced-oxidized [GSH: GSSG], catalase [CAT], superoxide dismutase [SOD], lipid hydroperoxides). We found that exposure to indirect GBH has no single or interactive effects in combination with the insecticide on larval survival. However, prior exposure to GBH inhibits Ldace1 gene expression by 0.55-fold, which is the target site for the organophosphate and carbamate insecticides. This difference disappears when individuals are exposed to both GBH and insecticide, suggesting an antagonistic effect. On the other hand, oxidative status biomarker scores (PCAs of GPx, GR, and CAT) were decreased when exposed to both stressors, indicating a synergistic effect. Overall, we found that indirect GBH exposure can have both antagonistic and synergistic effects in combination with an insecticide, which should be considered when aiming for an ecologically relevant risk assessment of multiple human-induced stressors.

Transcriptome and proteome analyses to investigate the molecular underpinnings of cold response in the Colorado potato beetle, Leptinotarsa decemlineata

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an insect that can cope with prolonged periods of low temperatures exposure. The molecular changes required to adapt to such conditions have not been thoroughly investigated in this insect. The current work aims at characterizing deregulated transcripts and proteins in adult L. decemlineata exposed to 15 °C and −5 °C using RNA-sequencing-based transcriptomics and liquid chromatography tandem mass spectrometry (LC-MS/MS)-based proteomics approaches, respectively. RNA-sequencing highlighted the differential expression of several transcripts, including ubiquilin-1 and ubiquitin carboxyl-terminal hydrolase 5, in insects submitted to low temperatures when compared with control insects. In addition, proteomics approach detected 2840 proteins in cold-exposed beetles including elevated levels for 409 proteins and reduced levels for 200 proteins. Cuticular proteins CP1, CP4, CP5 and CP7 as well as eukaryotic translation initiation factor 4B were notable proteins with elevated levels in cold insects. Functional analysis of targets modulated at low temperatures using DAVID indicated processes likely affected under cold conditions including select metabolic cascades and RNA-associated processes. Overall, this work presents molecular candidates impacted by low temperatures exposure in L. decemlineata and builds on the current knowledge associated with response to these conditions in this insect.

Expression status of heat shock proteins in response to cold, heat, or insecticide exposure in the Colorado potato beetle Leptinotarsa decemlineata.

The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is an agricultural pest that threatens the potato industry worldwide. This insect is widely regarded as one of the most difficult-to-control pests, as it can thrive in a wide range of temperature conditions and routinely develops resistance towards various insecticides. The molecular changes associated with response to these challenges have not been fully investigated in L. decemlineata. While differential expression and characterization of heat shock proteins (HSPs) in response to stress have been conducted in several insects, data regarding HSPs in L. decemlineata are limited. The overarching objective of this study consisted of evaluating the expression of various HSPs in L. decemlineata exposed to different temperatures or treated with the insecticides imidacloprid and chlorantraniliprole. Expression levels of HSP60, HSP70, HSP90, and HSP Beta-1 were evaluated by qRT-PCR and insect mortality was assessed using dsRNAs aimed at select HSP targets. Elevated HSP70 and HSP90 transcript levels were observed in heat-exposed L. decemlineata while downregulation of HSP70 transcript levels was measured in insects submitted to cold conditions. Chlorantraniliprole exposure was associated with reduced HSP Beta-1 transcript levels while no change in expression was monitored in insects exposed to imidacloprid. RNAi-based knockdown of HSP60 levels correlated with significant insect mortality 14days after dsRNA injection. These results highlight the modulation of HSPs that occur in L. decemlineata exposed to fluctuating temperatures and position HSPs as interesting candidates in the identification of novel molecular leads that could be targeted to control this insect.

An effective pest management approach in potato to combat insect pests and herbicide.

Insect pests and weeds incur significant yield losses to potato crop worldwide. The increasing crop losses provide impetus for the development of pest management strategy that is equally effective against insect pests and weeds. In the present study, a molecular approach was used to develop transgenicpotato lines(cv. Marabel) effective against Colorado potato beetle (Leptinotarsa decemlineata Say), potato tuber moth (Phthorimaea operculella Z.) and Basta® application. Agrobacterium tumefaciens strain EHA105 harboring binary vector pTF101.1 containing cry1Ac gene under the control of 35S and AoPR1 promoters was used to infect leaf discs and internodal explants. Phosphinothrincin was used at optimal concentration (2mg/l) for the screening of primary transformants. The standard molecular assays exhibited gene integration and expression in putative transgenics. Real-time data revealed up to ninefold high cry1Ac transcript levels, whereas cry protein amount was estimated to 0.4ppm in primary transformants. The analysis of first tuber progeny showed proper integration cry1Ac and bar genes in subsequent progeny. The transgenic plants also showed tolerance to the application of Basta®. The efficacy of cry1Ac was evaluated by allowing larvae of Colorado potato beetle (CPB) and potato tuber moth (PTM) to feed on transgenic plants. Results revealed appreciable mortality levels of different larval instars of CPB (20-100%) and PTM (50-100%). Overall, our results exhibit the potential of these transgenic lines to be used in a potato breeding program with the purpose to control insect pests and weeds.

Alien leaf beetles (Coleoptera, Chrysomelidae) of European Russia and some general tendencies of leaf beetle invasions.

Invasions of leaf beetles can cause tremendous economic consequences because some of these insects become major pests in invaded territories. We present the first inventory of alien Chrysomelidae of European Russia that appeared in the region in the 20th and 21st centuries (9 species) with analysis of the history of their invasions and detailed maps of distribution. This case study revealed some general tendencies of invasions of leaf beetles: (1) Recently, a dramatic increase in the rate of Chrysomelidae invasions is observed, which reflects the increase in international trade of living plants; (2) Alien leaf beetles can spread quickly, occupying almost all of Europe within several decades; (3) When the range of some leaf beetle species is quickly expanding, or when the species has been recorded established somewhere outside the native range, this species should be regarded as a potential invader worldwide. and (4) Alien leaf beetles usually occur on alien or cultivated plants, but some become naturalized in native communities. The specific information was the following. Two species native to the Mediterranean region, Chrysolina americana (feeds on Rosmarinus and Lavandula) and Leptomona erythrocephala (feeds on Lotus corniculatus) were recorded in European Russia for the first time. A polyphagous pest of floriculture Luperomorpha xanthodera native to China and Korea and a pest of soybeans Medythia nigrobilineata native to east Asia have been in the region since 2016. A pest of tobacco Epitrix hirtipennis native to North America has occurred since 2011. A pest of corn Diabrotica virgifera was intercepted at the border of Russia in 2011 but has not established. Three alien species have been in the region since the 20th century: Zygogramma suturalis introduced from North America for control of Ambrosia, Phyllotreta reitteri native to Afghanistan and Tajikistan and feeding on Lepidium latifolium, and the Colorado potato beetle Leptinotarsa decemlineata.

Variability in metabolic rate and gas exchange patterns of the Colorado potato beetle of winter and prolonged diapauses

AbstractWe compare standard metabolic rate (VCO2) and gas exchange patterns in the Colorado potato beetle (Leptinotarsa decemlineata Say) in winter diapause (i.e. lasting only one overwintering period) with those of beetles in prolonged diapause (i.e. diapause lasting 2 or 3 years). The length of diapause is estimated by the behaviour of the beetles: burrowing into soil as a sign of the beginning of diapause and emergence from the soil as the ending of diapause. Measurement with a flow‐through carbon dioxide (CO2) infrared gas analyzer reveals that most beetles in winter or prolonged diapause display distinct discontinuous gas exchange cycles at 23 °C. Beetles with cyclic gas exchange and continuous breathing do not survive the winter. Beetles in prolonged diapause are characterized by a three‐ to five‐fold lower standard metabolic rates, longer discontinuous gas exchange periods and shorter CO2 releases (open phase) than those in winter diapause.

Oxidative stress and cytogenetic effects in root tip cells of Allium cepa L. induced by alcoholic extracts of Leptinotarsa decemlineata (Say)

The harmful potential of the Colorado potato beetle (Leptinotarsa decemlineata (Say)), and its resistance to many insecticides in current use have drawn the attention of specialists across the worl...