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In October 2018, catastrophic Hurricane Michael caused $1.7 billion in damage to standing timber in Florida, USA. To inform recovery efforts, varying levels of damaged (low, moderate, and high) slash pine (Pinus elliottii Engelm) stands were sampled for woodboring beetles (Coleoptera: Buprestidae; Cerambycidae). These beetles generally colonize stressed and damaged trees, and their larval tunneling activities reduce the value of timber salvaged post disturbance. From 2019 to 2020, 3,810 adults of 32 species were trapped. Acanthocinus obsoletus Olivier and Monochamus sp. complex (M. titillator Fabricius; M. carolinensis Olivier) comprised 86% of all catches. Approximately 50% and 60% more woodborers, especially Monochamus sp., were trapped in moderate-damage stands in 2019 than in high- and low-damage stands, respectively. This trend was not present in 2020. From 2019 to 2020, total catches increased by ~29%, reflected by increases in Monochamus sp. and Xylotrechus sagittatus Germar. In 2019, high-damage stands had the greatest species richness, followed by low- and moderate-damage stands. Species composition in 2019 did not differ among variously damaged stands, but was more heterogeneous in low-damage than high-damage stands in 2020. Results indicate that timely salvage harvesting of moderate- and high-damage stands after catastrophic wind disturbances may lower the economic impacts by subcortical woodboring beetles.

Pleiotropic roles are proposed for brain extracellular vesicles (EVs) in the development of Alzheimer's disease (AD). Our previous studies have suggested a beneficial role for EVs in AD, where the endosomal system in vulnerable neurons is compromised, contributing to the removal of accumulated material from neurons. However, the involvement of EVs in propagating AD amyloidosis throughout the brain has been considered because the amyloid‐β precursor protein (APP), APP metabolites, and key APP cleaving enzymes were identified in association with EVs. Here, we undertook to determine whether the secretase machinery is actively processing APP in EVs isolated from the brains of wild‐type and APP overexpressing Tg2576 mice. We found that full‐length APP is cleaved in EVs incubated in the absence of cells. The resulting metabolites, both α‐ and β‐APP carboxyl‐terminal fragments and APP intracellular domain accumulate in EVs over time and amyloid‐β dimerizes. Thus, EVs contribute to the removal from neurons and transport of APP‐derived neurotoxic peptides. While this is potentially a venue for propagation of the pathology throughout the brain, it may contribute to efficient removal of neurotoxic peptides from the brain.

Bark beetle (Coleoptera: Curculionidae: Scolytinae) outbreaks can be spectacular, killing trees across hundreds to thousands of hectares or more of forest land. As bark beetles are a natural disturbance agent, it is hypothesized that ecosystems are adapted to such periodic disturbances. Under climate change, however, these beetle outbreaks have become more severe, persistent, and chronic on many landscapes, bringing into question the long-term resilience of these forests and the biota that depend on them. Our chapter objective is to review and generalize the effects of bark beetle outbreaks on flora, fauna, and soil microbiota across diverse landscapes worldwide. Through loss of canopy trees, there is an increase in forest gaps and dead organic material that alters resource availability for many organisms. As organisms respond to altered resources, they may create feedback loops to themselves and their environment. Tree regeneration dynamics may set the stage for dominance by the same or different canopy species, retriggering, advancing, or otherwise altering successional trajectories. Herbs and shrubs often become more abundant and diverse under postbark beetle outbreaks due to increased light, water, and nutrient availability. Faunal species that rely on open habitat conditions and greater availability of newly available resources (e.g., coarse woody debris, bark beetles as prey items, and understory plant release) tend to benefit from bark beetle outbreaks; vice versa for other species; and variable responses are indicated for other species. Both positive and negative impacts on red-listed or endangered species have been reported. Ectomycorrhizal and saprophytic fungi, respectively, tend to decrease and increase after bark beetle outbreaks. There may be an increase in soil bacteria with different bacterial species dominant in beetle-killed trees. Responses of biota are therefore species-specific, and there are winners and losers in systems based on habitat alterations and life-history requirements. Longer-term and comprehensive studies of cascading, interacting, and simultaneous ecological impacts for multitaxa are recommended for maintaining the resilience of these disturbed landscapes under climate change.

Newly identified mitovesicles are a type of extracellular vesicles whose levels and cargo are altered in Down syndrome., Mitochondrial dysfunction is an established hallmark of aging and neurodegenerative disorders such as Down syndrome (DS) and Alzheimer’s disease (AD). Using a high-resolution density gradient separation of extracellular vesicles (EVs) isolated from murine and human DS and diploid control brains, we identify and characterize a previously unknown population of double-membraned EVs containing multiple mitochondrial proteins distinct from previously described EV subtypes, including microvesicles and exosomes. We term these newly identified mitochondria-derived EVs “mitovesicles.” We demonstrate that brain-derived mitovesicles contain a specific subset of mitochondrial constituents and that their levels and cargo are altered during pathophysiological processes where mitochondrial dysfunction occurs, including in DS. The development of a method for the selective isolation of mitovesicles paves the way for the characterization in vivo of biological processes connecting EV biology and mitochondria dynamics and for innovative therapeutic and diagnostic strategies.

The University of Tennessee Herbarium (TENN) presents a case study for modernizing an historic seed collection. TENN staff recently rediscovered the J. K. Underwood Seed Collection (ca. 1931–1964), containing over 700 unique specimens, hidden away in storage. We employed a series of curation actions to modernize the collection and render it useful to researchers. This included physically organizing and digitally indexing the collection, updating scientific names to current taxonomy, storing the specimens in modern archival-quality containers, housing the collection in environmentally-controlled conditions, and increasing accessibility of the collection by photographing specimens and integrating these images into our existing website (tenn.bio.utk.edu). Our efforts also included developing a protocol for adding new accessions to the collection and advertising the utility of the collection as a source of morphological data on seeds for identification, research, and teaching. We also review modern strategies for curating seed collections. Specifically, we emphasize the importance of increasing visibility of collections through visual, digital representations. This expands the utility of collections and fosters global information sharing across disciplines. We present our curation project as a case study that can serve as a model for curating historic seed collections.

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Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaiosome phytochemical profiles explain the differential attractiveness of five species in the genus Trillium to eastern North American forest ants. Species were ranked from least to most attractive based on empirically‐derived seed dispersal probabilities in our study system, and we compared diaspore traits to test our hypotheses that more attractive species will have larger diaspores, greater concentrations of elaiosome fatty acids, and distinct elaiosome phytochemistry compared to the less attractive species. Diaspore length, width, mass, and elaiosome length were significantly greater in the more attractive species. Using gas chromatography–mass spectrometry, we found significantly higher concentrations of oleic, linoleic, hexadecenoic, stearic, palmitoleic, and total fatty acids in elaiosomes of the more attractive species. Multivariate assessments revealed that elaiosome phytochemical profiles, identified through liquid chromatography–mass spectrometry, were more homogeneous for the more attractive species. Random forest classification models (RFCM) identified several elaiosome phytochemicals that differed significantly among species. Random forest regression models revealed that some of the compounds identified by RFCM, including methylhistidine (α‐amino acid) and d‐glucarate (carbohydrate), were positively related to seed dispersal probabilities, while others, including salicylate (salicylic acid) and citrulline (L‐α‐amino acid), were negatively related. These results supported our hypotheses that the more attractive species of Trillium—which are geographically widespread compared to their less attractive, endemic congeners—are characterized by larger diaspores, greater concentrations of fatty acids, and distinct elaiosome phytochemistry. Further advances in our understanding of seed dispersal effectiveness in myrmecochorous systems will benefit from a portrayal of dispersal unit chemical and physical traits, and their combined responses to selection pressures., To investigate seed attributes that might impact attractiveness to ant dispersers, diaspore morphology, elaiosome phytochemistry, and elaiosome fatty acid profiles of five eastern North American species of Trillium that vary in their level of attractiveness to ant dispersers were assessed and compared. Seed attractiveness, measured as dispersal probability, was found to be related to broad interspecific differences in composition of elaiosome phytochemistry, to high concentrations of elaiosome fatty acids, and to larger diaspore width, length, mass, and elaiosome length. Further advances in our understanding of seed dispersal in myrmecochorous systems will require a portrayal of dispersal‐unit chemical and physical traits, and their combined responses to selection pressures.

Down syndrome (DS) is characterized by cognitive deficits throughout the lifespan and with the development of aging-dependent Alzheimer’s type neuropathology, which is related to the triplication of the amyloid β precursor protein (APP) gene. A dysfunctional endosomal system in neurons is an early characteristic of DS and APP-metabolites accumulate in endosomes in DS neurons. We have previously shown enhanced release of exosomes in the brain of DS patients and the mouse model of DS Ts[Rb(12.17(16))]2Cje (Ts2), and by DS fibroblasts, as compared to diploid controls. Here, we demonstrate that exosome-enriched extracellular vesicles (hereafter called EVs) isolated from the brain of DS patients, Ts2 mice and from the culture media of human DS fibroblasts are enriched in APP carboxyl-terminal fragments (APP-CTFs) as compared with diploid controls. Moreover, APP-CTFs levels increase in an age-dependent manner in EVs isolated from the brain of Ts2 mice. The release of APP-CTFs-enriched exosomes may have a pathogenic role by transporting APP-CTFs into naïve neurons and propagating these neurotoxic metabolites, which are also a source of amyloid β, throughout the brain, but also provides a benefit to DS neurons by shedding APP-CTFs accumulated intracellularly.

Fruit ripeness can be indicated through changes in chromaticity, luminance, odor, hardness, and size to attract seed dispersing animals. We quantified these attributes for both ripe and unripe fruits of 31 lemur-dispersed plant species in Ankarafantsika National Park, a tropical dry forest in northwestern Madagascar. We used spectroscopy, gas-chromatography mass-spectrometry, and a modified force gauge to quantify chromaticity, luminance, odor, and hardness. We compared these traits between unripe and ripe fruits of each species to determine which traits reliably indicate fruit ripeness across species. Overall, ripe fruits were significantly heavier and softer than unripe fruits. Ripe fruits were not more chromatically-conspicuous or odiferous relative to unripe fruits, nor were ripe fruits more conspicuous in the luminance channel. Contrary to expectation, our findings indicate that, in this particular system, plant-lemur interactions may be strongly mediated by haptic traits, such as fruit hardness, which are consistent and reliable indicators of fruit ripeness. Despite the potential importance of haptic indicators of fruit ripeness, they are underrepresented in the literature on sensory ecology.

Premise of the study Comparing ecological attributes of endemic species with related, widespread species can reveal differences accounting for rarity. Forests of the southeastern United States are home to many range-restricted endemic and widespread species of Trillium, a genus of ant-dispersed herbs. Evidence suggests that aspects of seed-related life history stages are often correlated with plant rarity, but few studies have tested whether the process of seed dispersal differs for endemic and widespread species. To address this question, we compared aspects of seed dispersal effectiveness (SDE) for three sympatric, widespread endemic Trillium species pairs. Methods We observed seed dispersal for Trillium species pairs by ants at eight sites, recorded numbers of seeds dispersed and dispersal distances, and described disperser interactions. To test disperser preference, we presented seeds of each pair to captive colonies of Aphaenogaster picea, a keystone disperser. Seeds were assigned scores based on worker behavior, and we recorded proportions of seeds dispersed after 1 h and 24 h. Key results Field observations yielded some significant within-pair differences. Ants dispersed more seeds of widespread species for all pairs, although dispersal distances did not differ. In laboratory experiments, after 24 h, ants dispersed more seeds of widespread species into nests. Conclusions Endemic Trillium species had lower overall SDE than did their widespread congeners. These findings add to the list of ecological and demographic challenges that face endemic plants when compared to common congeners. Lower SDE may negatively impact reproductive rates and the colonization of new habitats, which may contribute to patterns of endemism.