Drought increases Norway spruce susceptibility to the Eurasian spruce bark beetle and its associated fungi.

Drought affects the complex interactions between Norway spruce, the bark beetle Ips typographus and associated microorganisms. We investigated the interplay of tree water status, defense and carbohydrate reserves with the incidence of bark beetle attack and infection of associated fungi in mature spruce trees. We installed roofs to induce a 2-yr moderate drought in a managed spruce stand to examine a maximum of 10 roof and 10 control trees for resin flow (RF), predawn twig water potentials, terpene, phenolic and carbohydrate bark concentrations, and bark beetle borings in field bioassays before and after inoculation with Endoconidiophora polonica and Grosmannia penicillata. Drought-stressed trees showed more attacks and significantly longer fungal lesions than controls, but maintained terpene resin defenses at predrought levels. Reduced RF and lower mono- and diterpene, but not phenolic concentrations were linked with increased host selection. Bark beetle attack and fungi stimulated chemical defenses, yet G. penicillata reduced phenolic and carbohydrate contents. Chemical defenses did not decrease under mild, prolonged drought in our simulated small-scale biotic infestations. However, during natural mass attacks, reductions in carbon fixation under drought, in combination with fungal consumption of carbohydrates, may deplete tree defenses and facilitate colonization by I. typographus.

Grand challenges in entomology: Priorities for action in the coming decades.

Entomology is key to understanding terrestrial and freshwater ecosystems at a time of unprecedented anthropogenic environmental change and offers substantial untapped potential to benefit humanity in a variety of ways, from improving agricultural practices to managing vector-borne diseases and inspiring technological advances.We identified high priority challenges for entomology using an inclusive, open, and democratic four-stage prioritisation approach, conducted among the membership and affiliates (hereafter 'members') of the UK-based Royal Entomological Society (RES).A list of 710 challenges was gathered from 189 RES members. Thematic analysis was used to group suggestions, followed by an online vote to determine initial priorities, which were subsequently ranked during an online workshop involving 37 participants.The outcome was a set of 61 priority challenges within four groupings of related themes: (i) 'Fundamental Research' (themes: Taxonomy, 'Blue Skies' [defined as research ideas without immediate practical application], Methods and Techniques); (ii) 'Anthropogenic Impacts and Conservation' (themes: Anthropogenic Impacts, Conservation Options); (iii) 'Uses, Ecosystem Services and Disservices' (themes: Ecosystem Benefits, Technology and Resources [use of insects as a resource, or as inspiration], Pests); (iv) 'Collaboration, Engagement and Training' (themes: Knowledge Access, Training and Collaboration, Societal Engagement).Priority challenges encompass research questions, funding objectives, new technologies, and priorities for outreach and engagement. Examples include training taxonomists, establishing a global network of insect monitoring sites, understanding the extent of insect declines, exploring roles of cultivated insects in food supply chains, and connecting professional with amateur entomologists. Responses to different challenges could be led by amateur and professional entomologists, at all career stages.Overall, the challenges provide a diverse array of options to inspire and initiate entomological activities and reveal the potential of entomology to contribute to addressing global challenges related to human health and well-being, and environmental change.

Unveiling Chemical Cues of Insect-Tree and Insect-Insect Interactions for the Eucalyptus Weevil and Its Egg Parasitoid by Multidimensional Gas Chromatographic Methods.

Multidimensional gas chromatography is, presently, an established and powerful analytical tool, due to higher resolving power than the classical 1D chromatographic approaches. Applied to multiple areas, it allows to isolate, detect and identify a larger number of compounds present in complex matrices, even in trace amounts. Research was conducted to determine which compounds, emitted by host plants of the eucalyptus weevil, Gonipterus platensis, might mediate host selection behavior. The identification of a pheromone blend of G. platensis is presented, revealing to be more attractive to weevils of both sexes, than the individual compounds. The volatile organic compounds (VOCs) were collected by headspace solid phase microextraction (HS-SPME), MonoTrapTM disks, and simultaneous distillation-extraction (SDE). Combining one dimensional (1D) and two-dimensional (2D) chromatographic systems-comprehensive and heart-cut two-dimensional gas chromatography (GC×GC and H/C-MD-GC, respectively) with mass spectrometry (MS) and electroantennographic (EAD) detection, enabled the selection and identification of pertinent semiochemicals which were detected by the insect antennal olfactory system. The behavioral effect of a selected blend of compounds was assessed in a two-arm olfactometer with ten parallel walking chambers, coupled to video tracking and data analysis software. An active blend, composed by cis and trans-verbenol, verbenene, myrtenol and trans-pinocarveol was achieved.

Experimental evidence for heritable reproductive time in 2 allochronic populations of pine processionary moth.

Phenology allows organisms to overcome seasonally variable conditions through life-cycle adjustment. Changes in phenology can drastically modify the evolutionary trajectory of a population, while a shift in the reproductive time may cause allochronic differentiation. The hypothesis of heritable reproductive time was experimentally tested, by studying a unique population of the pine processionary moth Thaumetopoea pityocampa (Den. & Schiff.) which has a shifted phenology, and however co-occurs with the typical population following the classical life cycle. When populations of both types were reared under controlled conditions, the reproductive time was maintained asynchronous, as observed in the field. The shifted population was manipulated in the laboratory to reproduce later than usual, yet the offspring emerged in the next year at the expected dates thus "coming back" to the usual cycle. Hybrids from crosses performed between the 2 populations showed an intermediate phenology. From the emergence times of parents and offspring, a high heritability of the reproductive time (h = 0.76) was observed. The offspring obtained from each type of cross was genetically characterized using microsatellite markers. Bayesian clustering analysis confirmed that hybrids can be successfully identified and separated from the parental genetic classes by genotyping. Findings support the hypothesis that, for this particular population, incipient allochronic speciation is due to a heritable shift in the reproductive time that further causes assortative mating and might eventually cause ecological adaptation/maladaptation in response to environmental changes.

A review of invasive alien species impacts on eucalypt stands and citrus orchards ecosystem services: towards an integrated management approach.

Multidisciplinary knowledge on the impact caused by invasive alien species (IAS) on ecosystems is crucial for guiding policy makers in the adoption of sustainable management measures. This research was focused on insect IAS impacts on two managed ecosystems: eucalypt plantations and citrus orchards. It begins with an identification of the wide range of ecosystem services (ES) and disservices provided by each of these managed ecosystems, according to the methodology proposed by the Millennium Ecosystem Assessment. Subsequently, a comprehensive review of studies that promoted the identification and valuation of direct and indirect impacts IAS impacts on these ecosystems was performed. From the synthesis of previous findings, an integrative management framework is advanced. This links the identification of ES, drivers of change and development of IAS management strategies by means of assessment processes that account for multiple dimensions of ES values. The article concludes with a discussion on the challenges underpinning assessment and valuation approaches that inform the design of inclusive strategies and interventions to tackle IAS impacts.

Phenotypic divergence in reproductive traits of a moth population experiencing a phenological shift.

Allochrony that is reproductive isolation by time may further lead to divergence of reproductive adaptive traits in response to different environmental pressures over time. A unique "summer" population of the pine processionary moth Thaumetopoea pityocampa, reproductively isolated from the typical winter populations by allochronic differentiation, is here analyzed. This allochronically shifted population reproduces in the spring and develops in the summer, whereas "winter" populations reproduce in the late summer and have winter larval development. Both summer and winter populations coexist in the same pine stands, yet they face different climatic pressures as their active stages are present in different seasons. The occurrence of significant differences between the reproductive traits of the summer population and the typical winter populations (either sympatric or allopatric) is thus hypothesized. Female fecundity, egg size, egg covering, and egg parasitism were analyzed showing that the egg load was lower and that egg size was higher in the summer population than in all the studied winter populations. The scales that cover the egg batches of T. pityocampa differed significantly between populations in shape and color, resulting in a looser and darker covering in the summer population. The single specialist egg parasitoid species of this moth was almost missing in the summer population, and the overall parasitism rates were lower than in the winter population. Results suggest the occurrence of phenotypic differentiation between the summer population and the typical T. pityocampa winter populations for the life-history traits studied. This work provides an insight into how ecological divergence may follow the process of allochronic reproductive isolation.

Economic assessment of managing processionary moth in pine forests: a case-study in Portugal.

This paper assesses the private and social profitability of current strategies for managing processionary moth (Thaumetopoea pityocampa) in Portuguese pine forests, looking at economic and environmental costs and benefits. Costs include the expenses for forest treatment and the social costs of threats to human health (dermatitis amongst others); benefits are assessed in terms of both revenue and social benefits such as carbon fixation and recreation. The evaluation was done using Cost Benefit Analysis (CBA) as an analytical framework. While this tool is currently applied to forest and environmental assessment and specific applications to pest management strategies are to be found in agricultural economics, rather few attempts have been made in the field of forest pest management. In order to assess and compare with--without options, a case-study was analysed for the Setúbal Peninsula, south of Lisbon, an area where extensive stands of maritime pine (Pinus pinaster) grow. The exercise has shown that CBA can be a valuable tool for assessing the economic and social profitability of pest management. The results demonstrate that the loss of revenues in the no-management option is not sufficient to make pest management profitable for private forest owners in the short-term. Conversely, a social profit is gained as pest management minimizes health risks for humans and avoids possible recreational losses.

Genetic isolation through time: allochronic differentiation of a phenologically atypical population of the pine processionary moth.

Allochronic speciation refers to a mode of sympatric speciation in which the differentiation of populations is primarily due to a phenological shift without habitat or host change. However, it has been so far rarely documented. The present paper reports on a plausible case of allochronic differentiation between sympatric populations of the pine processionary moth (PPM), Thaumetopoea pityocampa. The PPM is a Mediterranean insect with winter larval development. A phenologically atypical population with early adult activity and summer larval development was detected 10 years ago in Portugal. Mitochondrial and nuclear sequences strongly suggest that the 'summer' individuals are closely related to the sympatric winter population, while microsatellite data show a reduction in allelic richness, a distortion of allelic frequencies and significant genetic differentiation. Moreover, monitoring of adult flights suggests that reproductive activity does not overlap between the summer and winter populations. We postulate that the summer population appeared after a sudden phenological shift of some individuals of the sympatric winter population, leading to a founder effect and complete reproductive isolation. Given that the individuals showing this new phenology are subject to different selection pressures, the observed allochronic differentiation may rapidly lead to deeper divergence.