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Insects communicating with pheromones, be it sex- or aggregation pheromones, are confronted with an olfactory environment rich in a diversity of volatile organic compounds of which plants are the main releaser. Certain of these volatiles can represent behaviorally relevant information, such as indications about host- or non-host plants; others will provide essentially a rich odor background out of which the behaviorally relevant information needs to be extracted. In an attempt to disentangle mechanisms of pheromone communication in a rich olfactory environment, which might underlie interactions between intraspecific signals and a background, we will summarize recent literature on pheromone/plant volatile interactions. Starting from molecular mechanisms, describing the peripheral detection and central nervous integration of pheromone-plant volatile mixtures, we will end with behavioral output in response to such mixtures and its plasticity. [ABSTRACT FROM AUTHOR]

Simple Summary: Ecological interactions among organisms underpin the stability of ecological networks, which are responsible for species biodiversity in ecosystems. These interactions are currently threatened by environmental risks, mainly due to human activities, such as air pollution. Among air pollutants, tropospheric ozone (O3) is known to disrupt chemical communication between plants and their pollinators. Alarmingly, its concentration is likely to increase by two–four-fold in the next two decades. However, the direct effects of O3 on the behavior of pollinators themselves have not been investigated so far, even though insect behavior is key to their ecological interactions. In this study, we evaluated the potential effects of O3 at different field-realistic concentrations on the behavior of the fig wasp Blastophaga psenes, the exclusive pollinator of the Mediterranean fig species Ficus carica. We found that O3, even at low concentrations, induced abnormal motility in fig wasps, and that exposed individuals might only have a reduced chance of recovery. Overall, our findings indicate that O3 can affect pollinator behavior, which may have detrimental implications for pollination systems. Among anthropogenic environmental risks, air pollution has the potential to impact animal and plant physiology, as well as their interactions and the long-term survival of populations, which could threaten the functioning of ecosystems. What is especially alarming is that the concentration of tropospheric ozone (O3) has dramatically increased since pre-industrial times. However, the direct effects of O3 on the behavior of pollinators themselves have not been investigated so far even though insect behavior is key to their ecological interactions, which underpin the stability of ecological networks responsible for species biodiversity in ecosystems. In this study, we aim to determine the potential effects of O3 episodes at different field-realistic concentrations (0, 40, 80, 120, and 200 ppb for 60 min) on the behavior of the fig wasp Blastophaga psenes by monitoring exposed individuals hourly for 5 h after exposure. We found that ozone episodes induced major changes in insect behavior, which were already significant at 80 ppb with individuals displaying abnormal motility. The tracking over time clearly showed that exposed individuals might only have a reduced chance of recovery, with a decreasing proportion of active fig wasps despite the cessation of an O3 episode. These findings illustrate that O3 episodes can affect pollinator behavior, which may have detrimental implications for pollination systems. It is, therefore, of importance to assess the effects of O3 on insect behavior in order to predict how it could modify ecological interactions and species biodiversity in ecosystems. [ABSTRACT FROM AUTHOR]

The horned passalus (Odontotaenius disjunctus) is one of the most extensively studied saproxylic beetles in the eastern United States. For several decades this species has been the subject of investigations into the behaviors associated with subsociality as well as physiological responses to stress, and, most recently, the composition of its gut microbiome has been closely examined. However, no published study to date has characterized this beetle's broad-scale population genetic structure. Here, we conducted intensive geographic sampling throughout the southern Appalachian Mountains and surrounding areas and then assessed mitochondrial DNA (mtDNA) sequence variation among individuals. Unexpectedly, we discovered two divergent, yet broadly sympatric, mtDNA clades. Indeed, the magnitude of divergence between- vs. within-clades ranged from 5.9 to 7.5×, depending on the dataset under consideration, and members of the two lineages were often syntopic (i.e., found in the same rotting log). Given the potential implications for past and future studies on behavior, physiology, and the gut microbiome, we developed a simple cost-efficient molecular assay (i.e., polymerase chain reaction restriction fragment length polymorphism; PCR-RFLP) to rapidly determine mtDNA clade membership of O. disjunctus individuals. We suggest that the evolutionary processes that gave rise to the emergence and persistence of divergent sympatric lineages reported here warrant investigation, as this type of spatial-genetic pattern appears to be rare among southern Appalachian forest invertebrates. [ABSTRACT FROM AUTHOR]