Ophiostoma babimostense and Sporothrix europaea (Ascomycota, Ophiostomatales), two new ophiostomatalean species, associated with ambrosia and bark beetles in Norway and Poland.

A Festschrift for Stephen L. Wood

Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.

Bark beetles (sensu lato) colonize woody tissues like phloem or xylem and are associated with a broad range of micro-organisms. Specific fungi in the ascomycete orders Hypocreales, Microascales and Ophistomatales as well as the basidiomycete Russulales have been found to be of high importance for successful tree colonization and reproduction in many species. While fungal mutualisms are facultative for most phloem-colonizing bark beetles (sensu stricto), xylem-colonizing ambrosia beetles are long known to obligatorily depend on mutualistic fungi for nutrition of adults and larvae. Recently, a defensive role of fungal mutualists for their ambrosia beetle hosts was revealed: Few tested mutualists outcompeted other beetle-antagonistic fungi by their ability to produce, detoxify and metabolize ethanol, which is naturally occurring in stressed and/or dying trees that many ambrosia beetle species preferentially colonize. Here, we aim to test (i) how widespread beneficial effects of ethanol are among the independently evolved lineages of ambrosia beetle fungal mutualists and (ii) whether it is also present in common fungal symbionts of two bark beetle species (Ips typographus, Dendroctonus ponderosae) and some general fungal antagonists of bark and ambrosia beetle species. The majority of mutualistic ambrosia beetle fungi tested benefited (or at least were not harmed) by the presence of ethanol in terms of growth parameters (e.g., biomass), whereas fungal antagonists were inhibited. This confirms the competitive advantage of nutritional mutualists in the beetle’s preferred, ethanol-containing host material. Even though most bark beetle fungi are found in the same phylogenetic lineages and ancestral to the ambrosia beetle (sensu stricto) fungi, most of them were highly negatively affected by ethanol and only a nutritional mutualist of Dendroctonus ponderosae benefited, however. This suggests that ethanol tolerance is a derived trait in nutritional fungal mutualists, particularly in ambrosia beetles that show cooperative farming of their fungi.

Non-native bark and ambrosia beetles represent a threat to forests worldwide. Their invasion patterns are, however, still unclear. Here we investigated first, if the spread of non-native bark and ambrosia beetles is a gradual or a discontinuous process; second, which are the main correlates of their community structure; third, whether those correlates correspond to those of native species. We used data on species distribution of non-native and native scolytines in the continental 48 USA states. These data were analyzed through a beta-diversity index, partitioned into species richness differences and species replacement, using Mantel correlograms and non-metric multidimensional scaling (NMDS) ordination for identifying spatial patterns, and regression on distance matrices to test the association of climate (temperature, rainfall), forest (cover area, composition), geographical (distance), and human-related (import) variables with β-diversity components. For both non-native bark and ambrosia beetles, β-diversity was mainly composed of species richness difference than species replacement. For non-native bark beetles, a discontinuous invasion process composed of long distance jumps or multiple introduction events was apparent. Species richness differences were primarily correlated with differences in import values while temperature was the main correlate of species replacement. For non-native ambrosia beetles, a more continuous invasion process was apparent, with the pool of non-native species arriving in the coastal areas that tended to be filtered as they spread to interior portions of the continental USA. Species richness differences were mainly correlated with differences in rainfall among states, while rainfall and temperature were the main correlates of species replacement. Our study suggests that the different ecology of bark and ambrosia beetles influences their invasion process in new environments. The lower dependency that bark beetles have on climate allowed them to potentially colonize more areas within the USA, while non-native ambrosia beetles, being dependent on rainfall, are typically filtered by the environment.

1. Bark and ambrosia beetles are crucial for woody biomass decomposition in tropical forests worldwide. Despite that, quantitative data on their host specificity are scarce. 2. Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species of tropical trees representing 11 families from all major lineages of dicotyledonous plants. Standardised samples of beetle‐infested twigs, branches, trunks, and roots were taken from three individuals of each tree species growing in a lowland tropical rainforest in Papua New Guinea. 3. A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local species richness of bark and ambrosia beetles was estimated at 80–92 species. 4. Ambrosia beetles were broad generalists as 95% of species did not show any preference for a particular host species or clade. Similarity of ambrosia beetle communities from different tree species was not correlated with phylogenetic distances between tree species. Similarity of ambrosia beetle communities from individual conspecific trees was not higher than that from heterospecific trees and different parts of the trees hosted similar ambrosia beetle communities, as only a few species preferred particular tree parts. 5. In contrast, phloeophagous bark beetles showed strict specificity to host plant genus or family. However, this guild was poor in species (12 species) and restricted to only three plant families (Moraceae, Myristicaceae, Sapindaceae). 6. Local diversity of both bark and ambrosia beetles is not driven by the local diversity of trees in tropical forests, since ambrosia beetles display no host specificity and bark beetles are species poor and restricted to a few plant families.

Fire-mediated interactions between a tree-killing bark beetle and its competitors

BackgroundMangrove forests are of fundamental significance that support a diverse array of species, but despite their importance and the benefits they provide, the health of these trees is under constant threat. This is due to a variety of environmental and human factors, which lead to their weakening and susceptibility to colonization by insect pests. Although the diversity of bark and ambrosia beetles has been well documented worldwide, there is limited information available regarding their relationships with mangroves. To investigate the diversity and distribution of ambrosia and bark beetles associated with mangrove habitats in South Africa, extensive field surveys and species sampling across various mangrove sites were carried out, as well as Lindgren and Panel traps were installed along five estuaries in KwaZulu–Natal and one in the Eastern Cape Province, from October to December 2013 and January to February 2014.ResultsA total of 8677 individuals comprising 11 genera and 16 species of ambrosia and bark beetles were captured. Of these, the most abundant was Hypothenemus eruditus (n = 2178; 25.10%), followed by Ambrosiodmus natalensis (n = 863; 10.36%), Xyleborus affinis (n = 844; 9,73%) and Premnobius cavipennis (n = 833; 9,60%), respectively. The remaining species registered an incidence lower than 7%. From the analysis of representativeness by rarefaction curves, there was no trend toward an increase in species as the number of trajectories increased.ConclusionsThis research contributes to understanding the biodiversity of ambrosia and bark beetle assemblages within South African mangrove ecosystems and underscores the importance of conserving these habitats in the face of environmental and anthropogenic pressures. The findings provide a valuable baseline for future studies and management strategies aimed at preserving mangrove health and monitoring beetle community dynamics in these critical coastal environments.

Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of 763 beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi (host and air moisture), resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas.

Diseases associated with ambrosia and bark beetles comprise some of the most significant problems that have emerged on trees in the last century. They are caused by fungi in the Ophiostomatales, Microascales, and Hypocreales, and have vectors in the Scolytinae (ambrosia and bark beetles) and Platypodinae (ambrosia beetles) subfamilies of the Curculionidae (Coleoptera). Some of these problems, such as Dutch elm disease, have a long history, have been extensively researched, and are fairly well understood. In contrast, other similar diseases developed recently and are poorly or partially understood. The emergence and unexpected importance of these tree diseases are discussed in this article. An underlying factor in most of these interactions is the absence of a coevolved history between the so-called "naïve" or "new encounter" host trees and the pathogens and/or beetles. For the ambrosia beetles, these interactions are associated with susceptibility to what are typically benign fungi and atypical relationships with healthy trees (ambrosia beetles favor trees that are dead or stressed). Interestingly, the pathogens for both the ambrosia and bark beetle-associated diseases often have symbiotic relationships with the insects that are not based on phytopathogenicity. Some of the most alarming and damaging of these diseases are considered "black swan events". Black swan developed as a metaphor for a supposed impossibility that is contradicted with new information. Today, Black Swan Theory focuses on unexpected events of large magnitude and consequence.

1. INTRODUCTION Bark beetles in a wide sense include the true bark beetles (many Scolytidae), which breed in and feed on the phloem (phloeophagous species), and the ambrosia beetles (many Scolytidae, and all Platypodidae), which bore into the wood and feed primarily on symbiotic ambrosia fungi living in the tunnels (xylomycetophagousspecies). Some Scolytidae also develop in hard seeds and fruits (spermophagousspecies), in the central pith of twigs and other small stems, or in the petioles of fallenleaves (myelophagous species). We use the term 'bark beetles' to cover all thesecategories, unless otherwise specified. Bark beetles usually live in scattered habitat units, which are suitable for breeding for only a single generation of beetles. Thismeans that the new generation of adults must disperse to find new breeding sites.These two features mean that bark and ambrosia beetle populations are very variable both in space and time, depending on the spatial and temporal availability of suitablebreeding material. The study of their temporal and spatial dynamics is very important both because of their economic immportance in forests, and the ease withwhich these small beetles can be transported to, and become established in, newareas. The majority of species breed in dead or dying tissues, and are not normallyof economic importance. However, such species can become economicallyimportant if their galleries create holes in timber used for furniture or veneer, or if they transport pathogenic fungi to living trees during a period of feeding by young adults to mature the gonads. The relatively small number of species that attack livingtrees, saplings or seedlings, or the seeds off commercial crops (e.g. coffee, palms) aresometimes of major economic importance, causing damage estimated in millions of

In 2002-2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (-)-alpha-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25-28 degrees C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (-)-alpha-pinene lures (release rate, 2-6 g/day at 25-28 degrees C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (-)-alpha-pinene in some locations. (-)-alpha-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70-97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (-)-alpha-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.

Bark and ambrosia beetles (Coleoptera: Curculionidae:Scolytinae) include many important pest species of forest and fruit trees.  They usually prefer the physiologically stressed trees for colonization but also it is known that they attack healthy trees. Bark and ambrosia beetles are consisted of two main ecological groups, bark beetles grow in bark and ambrosia beetles in sapwood. Especially ambrosia beetles are very detrimental in Turkish hazelnut orchards. This study was carried out between 2005 and 2007 to monitor populations ofXyleborus dispar and Xyleborinus saxesenii (Col.: Scolytidae), causing considerable damages in hazelnut (Corylus avellana L.) orchards in Ordu and Samsun Provinces. The populations of the bark beetles were monitored using sticky traps with red wings that are registered and used to capture these pests. Ethyl alcohol (96%) was used as the attractant in the traps. The results of the three-year study indicated that both pest species emerged in different times in Ordu and Samsun. X. dispar emerged in large numbers in springs (March - May) as overwintered adults; however, X. saxesenii emerged in large numbers in summers (June - August). Population density is usually the X. dispar was found to be more.  X. dispar on 05.15.2007 (398 adult/trap), X. saxesenii on.09.01.2005 (383 adult/trap) the highest catch was recorded in Samsun province.   Key words: Hazelnut, monitoring population, Xyleborus dispar, Xyleborinus saxesenii, red winged sticky traps.

Abstract1 Sudden oak death is caused by the apparently introduced oomycete, Phytophthora ramorum. We investigated the role of bark and ambrosia beetles in disease progression in coast live oaks Quercus agrifolia.2 In two Marin County, California sites, 80 trees were inoculated in July 2002 with P. ramorum and 40 were wounded without inoculation. Half of the trees in each group were sprayed with the insecticide permethrin [cyclopropanecarboxylic acid, 3‐(2,2‐dichloroethenyl)‐2,2‐dimethyl‐(3‐phenoxyphenyl) methyl ester] to prevent ambrosia and bark beetle attacks, and then were sprayed twice per year thereafter. After each treatment, sticky traps were placed on only the permethrin‐treated trees. Beetles were collected periodically in 2003.3 Inoculated trees accounted for 95% of all beetles trapped. The ambrosia beetles Monarthrum scutellare and Xyleborinus saxeseni and the western oak bark beetle Pseudopityophthorus pubipennis were the most abundant of the seven species trapped.4 Permethrin treatment delayed initiation of beetle attacks and significantly reduced the mean number of attacks per tree. Beetles did not attack any wounded or noncankered inoculated trees.5 Trees with larger cankers trapped more beetles early in the disease. Once permethrin lost effectiveness, the number of beetle entrance tunnels was a more reliable predictor of subsequent trap catch than was canker size.6 Beetles were initially attracted to P. ramorum cankers in response to kairomones generated in the host‐pathogen interaction. After beetles attacked the permethrin‐treated trees, aggregation pheromones most probably were the principal factor in beetle colonization behaviour.

Bark and ambrosia beetles pose significant threats to the stability of forest stands worldwide, making their control crucial. Among these pests, Gnathotrichus materiarius, a polyphagous invasive ambrosia beetle living on conifers, has successfully established itself in Europe. Early identification of these pests plays a fundamental role in designing effective pest control strategies. The work aimed to assess the efficacy of different lures in Ecotrap® for capturing of invasive ambrosia bark beetles. The lures tested included Wood Stainers Lure (containing the potential pheromone sulcatol for capturing Gnathotrichus materiarius adults), α-pinene, ethanol UHR, and Cembräwit. The objective was to determine the most suitable lure for use in traps. In four locations in western Bohemia, a total of 7,410 individuals from 46 species of ambrosia and bark beetleswere captured. The abundance of invasive ambrosia beetles (Gnathotrichus materiarius, Cyclorhipidion bodoanum, Xyleborinus attenuatus, and Xylosandrus germanus) primarily depended on the day of the season and secondarily on the lure used. Although their population density was low, more beetles were caught using ethanol as the lure. Notably, these invasive ambrosia beetles accounted for less than 3 % of the total number of ambrosia and bark beetles detected (187 individuals). Ethanol was found to be a universal lure for attracting ambrosia beetles, with the majority of Scolytinae species being captured in traps baited with ethanol.

The extraordinary array of mating systems in the Scolytidae and Platypodidae has been largely overlooked by researchers interested in the evolution of sexual behaviour. This paper provides the first overview of reproductive behaviour in this important and widespread group, known to most biologists only by the reputations of tree-killing taxa. Referred to generally as ‘bark beetles’, these insects chew egg tunnels inside a variety of (usually dead) plant tissues, though most species are either phloeophagous (breeding in the inner bark of woody plants) or xylomycetophagous (all stages feeding on mutualistic fungi growing on sapwood or heartwood). In most species, permanent records of many aspects of reproductive behaviour are etched in the host; in many, engravings reveal female fecundity, eggs sired per male, hatching success, and offspring survivorship. Each gallery arm represents a good portion of a given female's lifetime reproduction, but in many species females commonly re-emerge to reproduce in one or two additional sites. In most species of bark beetles, each female initiates her own gallery, to be joined later by a male. These monogynous gallery systems are associated with mating systems defined by how long males stay with females: in a few species, males seldom if ever join females under the bark; in the vast majority of species, males stay for part or all of the oviposition period then leave to seek other mates; and a few groups exhibit permanent monogamy, in that both sexes die in their only gallery system. While these patterns emerge from an overview of the world scolytid fauna, the length of male residency has seldom been quantified, and the costs and benefits associated with male mating strategies have not been measured for any bark beetle. Male-initiated monogyny is uncommon in Scolytidae, though the rule in Platypodidae; all instances of which I am aware are summarized from a phylogenetic perspective. Inbreeding polygyny with highly biased sex ratios has arisen at least seven times in Scolytidae. These taxa are usually characterized by males being dwarfed, flightless, and uncommon. Sex determination is known for only a few examples, but both haplodiploidy and diplodiploidy have been reported. Multiple origins of harem polygyny (otherwise rare in invertebrates) add an exciting dimension to the comparative and experimental study of scolytid mating systems. In harem polygynous taxa, males initiate gallery construction. I summarize what little can be learned from the literature about the fine structure of harem polygynous mating systems in bark beetles, and the problem of measuring reproductive success. Data on the nature of harem polygyny in Pityophthorus lautus are presented, illustrating (a) the fluidity of harems; (b) that average eggs laid per gallery arm is relatively unaffected by harem size, but strongly influenced by resource quality; (c) that male egg-gain is strongly correlated with territory quality (a consequence of (b) above); and (d) the temporal patterning of immigration and emigration and its effects on gallery system sex ratios. The second half of this paper is a discussion of the evolution of bark and ambrosia beetle mating Mating systems, emphasizing sexual selection and the role of resources. Male, residence is interpreted as postcopulalory guarding—preventing sexual liaisons with wandering males. Operational sex ratio, encounter rate, synchrony of breeding, ejaculate competition, and spatiotemporal distribution of resources are discussed as evolutionary forces moulding scolytid and platypodid male postmating behaviour. The nature of male male competition is reviewed. The paucity of information on male behaviour in gallery systems is mentioned; whether or not males significantly aid females is not known. Three hypotheses are presented for why females re-emerge, a feature which strongly affects operational sex ratios. Finally, I summarize features of bark beetle existence predisposing them to the evolution of post-inseminative guarding. Male-initiated monogyny presents a puzzle. I propose that most uncontested examples can be explained by monogyny re-evolving from (male-initiated) harem polygyny, and I present an argument for the evolution of harem polygyny leading to the development of male gallery initiation. The evolution of harem polygyny in birds and mammals has attracted considerable attention. The Verner Willson Orians polygyny threshold model is discussed with respect to bark beetles in general and P. lautus in particular. Resource quality is a major factor in P. lautus harem dynamics: the cost to females of joining harems is apparently slight compared to benefits accrued from moving into sites with higher quality inner bark. Female-biased adult sex ratios have been suggested to lead to harem polygyny, and literature and original data pertinent to this hypothesis are examined. The geometric constraints model, based on the polygyny threshold concept but tailored to bark beetles, is proposed to account for the failure of most species to evolve harem polygyny, and testable predictions are derived that interrelate breeding systems, habitat quality, and progeny size. The evolution of Inbreeding is briefly covered, and two routes to inbreeding polygyny are suggested.