Fredrik Schlyter

Swedish University of Agricultural Sciences /Sveriges Lantbruksuniversitet (SLU) · Plant Protection Biology / Växtskyddsbiologi

Developing better practices for rodent pest control is of high importance to reduce damage during forest restoration and in crop production. For example, during direct seeding with large and highly attractive seeds such as acorns, most seeds will disappear due to consumption or dispersal if not protected. An unexplored concept in reducing rodent da...

In many species, polymorphic inversions underlie complex phenotypic polymorphisms and appear to facilitate local adaptation in the face of gene flow. Multiple polymorphic inversions can co-occur in a genome, but the prevalence, evolutionary significance, and limits to complexity of genomic inversion landscapes remain poorly understood. Here, we exa...

Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the...

One of the most promising techniques for rapid detection of bark beetle-infested trees is the use of specially trained dogs. Due to the novelty of using dogs in detecting bark beetle-infested trees, evaluation of success or comparison with the traditional approaches is lacking. Spruces were pre-treated with a synthetic pheromone at several tree pos...

Protection of Norway spruce stands using anti-attractants was tested during an outbreak of bark beetles (Ips typographus) in their spring flight. The aims of this study were as follows: (1) to test the proposed experimental design for tree protection; (2) to evaluate height-specific alternatives for dispenser installation on trees; and (3) to evalu...

The Eurasian spruce bark beetle, Ips typographus, is a major pest, capable of killing spruce forests during large population outbreaks. Recorded dispersal distances of individual beetles are typically within hundreds of meters or a few kilometers. However, the connectivity between populations at larger distances and longer time spans and how this i...

Plant traits are an expression of strategic tradeoffs in plant performance that determine variation in allocation of finite resources to alternate physiological functions. Climate factors interact with plant traits to mediate tree survival. This study investigated survival dynamics in Norway spruce (Picea abies) in relation to tree-level morphologi...

Background: Eurasian spruce bark beetles use both attractant and anti-attractant semiochemicals to find suitable mature host trees. trans-4-thujanol is abundant in young, unsuitable spruce trees. The electrophysiological studies have demonstrated its high activity levels, but field data are lacking. Results: Enantioselective GC-MS analysis showe...

Background Arvicolinae rodents are known pests causing damage to both agricultural and forest crops. Today, rodenticides for rodent control are widely discouraged due to their negative effects on the environment. Rodents are the main prey for several predators, and their complex olfactory system allows them to identify risks of predation. Therefore...

Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems. These species complete their life cycle in nutritionally poor substrates and some can kill enormous numbers of trees during population outbreaks. The Eurasian spruce bark beetle (Ips typographus) can destroy >100 million m3 of spruce in a single year. We rep...

Resilience and functionality of European Norway spruce forests are increasingly threatened by mass outbreaks of the bark beetle Ips typographus promoted by heat, wind throw and drought. Here, we review current knowledge on Norway spruce and I. typographus interactions from the perspective of drought-stressed trees, host selection, colonisation beha...

The present study was conducted to determine the role of guava fruit volatiles in attraction, oviposition and associated fitness parameters of the peach fruit fly, Bactrocera zonata Saunders, which is a key pest of guava and many other fruits. B. zonata female flies’ attraction was observed in a Y-tube olfactometer using fruits of three locally gro...

Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems. These species have evolved specializations to complete their life cycle in nutritionally poor wooden substrates and some can overwhelm tree defences and kill enormous numbers of trees during population outbreaks. The Eurasian spruce bark beetle ( Ips typogra...

Plant volatiles are the invisible players in the plant-insect co-evolutionary arms race. They are involved in various plant-mediated tri-trophic interactions within the ecosystem. Volatiles, emitted from different parts of the plant, serves as a cue for the host-seeking herbivores. Interestingly, insects perceive and process such complex environmen...

Restoration of mixed oak forest in northern temperate regions is important for biodiversity and for adaptation of forest management to climate change. Direct seeding has been considered as a cost-effective method for the assisted regeneration of oaks. However, removal of acorns by granivorous rodents hinders its application. Patterns of acorn remov...

The Eurasian spruce bark beetle ( Ips typographus [L.]), is a major killer of spruce forests across the Palearctic. During epidemics, it can destroy over 100 million cubic meters of spruce trees in a single year. Here we report a 236 Mb, highly contiguous I. typographus genome assembly using PacBio long-read sequencing. The final phased assembly ha...

Bark beetles often serve as forest damaging agents, causing landscape-level mortality. Understanding the biology and ecology of beetles are important for both, gathering knowledge about important forest insects and forest protection. Knowledge about the bark beetle gut-associated bacteria is one of the crucial yet surprisingly neglected areas of re...

Bark beetles are destructive forest pests considering their remarkable contribution to forest depletion. Their association with fungi is useful against the challenges of survival on the noxious and nutritionally limited substrate, i.e., conifer tissues. Fungal symbionts help the beetles in nutrient acquisition and detoxification of toxic tree secon...

Seed consumption by rodents causes substantial economic losses in agriculture and forest restoration. Rodents rely on their sensitive sense of smell to gather information about their environment. However, comparably little is known about how rodents use olfaction to locate food. We used bank voles to measure attraction to acorn odors in a Y-maze. P...

Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark su...

Key message The dog detection allows timely removal by sanitation logging of first beetle-attacked trees before offspring emergence, preventing local beetle increases. Detection dogs rapidly learned responding to synthetic bark beetle pheromone components, with known chemical titres, allowing search training during winter in laboratory and field. D...

Background: Deciphering the molecular mechanisms mediating the chemical senses, taste, and smell has been of vital importance for understanding the nature of how insects interact with their chemical environment. Several gene families are implicated in the uptake, recognition, and termination of chemical signaling, including binding proteins, chemo...

Background: This first task aim to generate a high-quality genome sequencing database as the best possible foundation for both currently ongoing EXTEMIT-K projects, but also to facilitate future efforts at the CULS, as well as provide a valuable resource to the bark beetle scientific community in general. Focusing on the context of EXTEMIT-K, this...

This is preprint on method to train bark beetle dog to find infested trees. It is under final revision after acceptance in Ann For Sci.

The onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a polyphagous pest that causes serious damage to agricultural crops, vegetables, and ornamental plants worldwide. Farmers rely on the extensive usage of synthetic chemical insecticides to control T. tabaci. There is a dire need to develop alternative control strategies to overco...

Seed consumption by granivorous rodents such as Myodes glareolus and Apodemus sylvaticus are one major drawback for the implementation of low-cost direct seeding in forest restoration programs around Europe. As a main prey for several mammal predators, rodents have evolved a complex olfactory system triggering anti-predation behaviors. Although fea...

Insects detect their hosts or mates primarily through olfaction, and olfactory receptors (ORs) are at the core of odorant detection. Each species has evolved a unique repertoire of ORs whose functional properties are expected to meet its ecological needs, though little is known about the molecular basis of olfaction outside Diptera. Here we report...

Supplementary Figures, Supplementary Tables and Supplementary References

Examination of closely related species pairs is suggested for evolutionary comparisons of different degrees of polyphagy, which we did here with three taxa of lepidopteran herbivores, Spodoptera spp (S. littoralis, S. frugiperda maize (C) and rice (R) strains) for a RNAseq analysis of the midguts from the 3rd instar insect larvae for differential m...

Bark beetles face challenges and trade-offs during host selection, imposed by lethal tree defences, lower nutrition and higher competition in less well-defended trees, scarcity and ephemeral distribution of susceptible hosts, limitation of suitable hosts to one beetle generation, and relatively short lifespan and vulnerability of adults during host...

Eastern Palearctic conifers are subject to frequent bark beetle outbreaks. However, neither the species responsible nor the semiochemicals guiding these attacks are well understood. Two high-mountain Ips species on Qinghai spruce, Picea crassifolia, I. shangrila and I. nitidus, are typical in this regard. Six synthetic candidate pheromone component...

Thesis manuscript. Behavioural field and laboratory studies on Ips typographus testing identified semio chemicals

Thesis manuscript. GC-EAD and SSR study on natural head space samples from host logs

Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we here show for olfactory responses. In cotton leafworm moths Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles is modulated after mating, producing a behavioural response that matches the physiological c...

Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological...

The pine processionary moth is, by far, the most important insect defoliator of pine forests in Southern Europe and North Africa, both in terms of its temporal occurrence, geographic range and socioeconomic impact. Monitoring and pest management actions are therefore required on a regular basis, to ensure the detection, evaluation and mitigation of...

The pine processionary moth is, by far, the most important insect defoliator of pine forests in Southern Europe and North Africa, both in terms of its temporal occurrence, geographic range and socioeconomic impact. Monitoring and pest management actions are therefore required on a regular basis, to ensure the detection, evaluation and mitigation of...

This is a title of a conference paper only; for a fuller story see the summary of the thesis which provides the published part of this work: http://pub.epsilon.slu.se/9440/11/binyamen_m_130215.pdf

The sense of smell is crucial for fitness of most animals, enabling them to find mates, food and egg laying sites and to stay away from danger. Hence, odour molecules are detected by sensitive and specific olfactory sensory neurons ( OSN s). In insects, the OSN s are stereotypically grouped into olfactory sensilla located mainly on the antennae. Th...

Phytophagous insects use blends of volatiles released from plants to select hosts for feeding and oviposition. To behaviorally analyze complex blends, we need efficient and selective methods for elucidating neuron types, their ligands, and specificity. Gas chromatography-combined single sensillum recordings (GC-SSRs) from antennal olfactory sensill...

The effects of the oviposition regime on egg maturation rate in the synovigenic parasitoid, Microplitis rufiventris Kokujev were investigated. In non-ovipositing wasps, females normally reach a peak of egg maturation rate on 1 d posteclosion. Egg maturation slowed down once the maximum oviduct egg load was reached on 2 d posteclosion. In wasps mani...

The leopard moth Zeuzera pyrina L. ( ZP ) is an invasive pest from Europe of increasing significance in North Africa, in particular for olive cultivation. We followed the temporal dynamics by combined light/pheromone trapping over a 10‐year period (2002–2011) in a 240‐ha olive farm in Northern Egypt. The ZP had an annual cycle with one or two peak...

Conifer feeding bark beetles (Coleoptera, Curculionidae, Scolytinae) pose a serious economic threat to forest production. Volatiles released by non-host angiosperm plants (so called non-host volatiles, NHV) have been shown to reduce the risk of attack by many bark beetle species, including the European spruce bark beetle, Ips typographus. However,...

In order to locate mates, food, and oviposition sites, insects mainly rely on volatile cues released by their sexual partners, food sources, and host and non-host plants. Calling, mating, and oviposition behaviors, as well as fecundity and longevity, of newly emerged Spodoptera littoralis (Bois.) moths were recorded in the presence of volatiles fro...

In order to locate mates, food, and oviposition sites, insects mainly rely on volatile cues released by their sexual partners, food sources, and host and non-host plants. Calling, mating, and oviposition behaviors, as well as fecundity and longevity, of newly emerged Spodoptera littoralis (Bois.) moths were recorded in the presence of volatiles fro...

The number of mature eggs carried by a female parasitoid at any given moment (egg load) is a fitness-related parameter affecting reproductive potential and impacting upon host population dynamics. Microplitis rufiventris Kokujev (Hymenoptera: Braconidae) is a solitary koinobiont endoparasitoid wasp of several noctuid pests, including Spodoptera lit...

Background The European spruce bark beetle, Ips typographus, and the North American mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae: Scolytinae), are severe pests of coniferous forests. Both bark beetle species utilize aggregation pheromones to coordinate mass-attacks on host trees, while odorants from host and non-host tre...

Accession numbers for genes encoding olfactory proteins that were submitted to GenBank and the Transcriptome Shotgun Assembly sequence database (TSA) at NCBI.

Gene ontology results. Gene ontology analyses as in Figure 1, but here represented as bar diagrams that have a higher resolution. A) Molecular function level 3 in Ips typographus, B) molecular function level 3 in Dendroctonus ponderosae, C) biological process level 2 in I. typographus, and D) biological process level 2 in D. ponderosae.

Presence of chemosensory proteins in various tissues of Dendroctonus ponderosae. Analyses of Sanger-specific data and normalized as well as non-normalized transcriptome assemblies from various body parts of D. ponderosae indicate that 4 of the 11 identified chemosensory proteins were found exclusively in non-antennal tissues. The numbers in the tab...

Shared chemosphere of I. typographusandD. ponderosae. List of 54 semiochemicals that are produced by the two bark beetle species, or present in their host or non-host plants and whether the compounds are active at a physiological and/or behavioral level in each species.

Presence of odorant binding proteins in various tissues of Dendroctonus ponderosae. Analyses of Sanger-specific data and normalized as well as non-normalized transcriptome assemblies from various body parts of D. ponderosae indicate that large sets of odorant binding proteins were found exclusively in non-antennal tissues. The numbers in the tables...

The olfactory sense determines vital steps in insect behaviour, including mate and food search, oviposition site selection and predator/parasitoid avoidance. As part of an international collaboration, we have established the noctuid moth, Spodoptera littoralis (the Egyptian Cotton Leafworm) as a model for investigation of noctuid olfaction and chem...

Chemical ecology has already provided tools for monitoring, mass-trapping, and relocation of forest insects, especially in conifer bark beetles. Here we demonstrate the use of detector dog to be effective for finding and locating spruces that has been recently infested by the European spruce bark beetle (Ips typographus L.), one of the most aggre...

Jasmine moth (JM), Palpita unionalis (Hübner) (Lepidoptera: Pyralidae) is a very important pest in the commercial, densely planted olive orchards in Egypt. In years of its highest population density, it can destroy a significant part of the crop. The objectives of this study were to determine the male flight trend and egg laying trend of the JM in...

Reduction of tree mortality caused by bark beetle attacks is not only important for forestry, but also essential for the preservation of biodiversity and forest carbon sinks in the face of climate change. While bark beetle mass trapping (a “pull” approach) is implemented in practice, few studies exist to estimate its effect. The more complex “push-...

Volatiles from bark of aspen, Populus tremula L. and two species of birch: silver birch (Betula pendula Roth.) and common birch (B. pubescens Ehrh.), were collected by direct solvent extraction and aeration of both newly cut bark chips and undamaged stems in June 1998 and subjected to GC-MS analysis. The results showed the presence of 2-methyl-3-bu...

Single-cell recordings from olfactory sensory neurons (OSNs), housed in sensilla located at the base and at the tip of the antenna, showed selective responses to plant odors and female sex pheromone in this polyphagous moth. A spatial variation existed in sensitivity: OSNs present on the more proximal segment (P) were more sensitive than those on t...

Secondary attraction to aggregation pheromones plays a central role in the host colonization behavior of the European spruce bark beetle Ips typographus. However, it is largely unknown how the beetles pioneering an attack locate suitable host trees, and eventually accept or reject them. To find possible biomarkers for host choice by I. typographus,...

Physiological studies on olfaction frequently ignore the airborne quantities of stimuli reaching the sensory organ. We used a gas chromatography–calibrated photoionization detector to estimate quantities released from standard Pasteur pipette stimulus cartridges during repeated puffing of 27 compounds and verified how lack of quantification could o...