Plant-derived or botanical insecticides are biopesticides experiencing substantial ongoing increase in interest. The 74 years of our literature survey tracked over 2500 papers on botanical insecticides published between 1945 and 2019 (Web of Science database). Such a survey allowed meta-analyses to recognize current status and biases of the studies providing important insights into the research topic. They include the recognition of the exponential growth of such studies since the 1990s, the prevalent interest on the Meliaceae plant species and a dozen additional families, although some 190 families have been investigated. The arthropods targeted by such studies were pest species (ca. 95%) with rather little attention devoted to non-target species (p < 0.001). This bias is followed by another one—mortality assessments are prevalent among target and non-target arthropod species when contrasted with sublethal assessments (p < 0.01). These omissions are pivotal, as they fail to recognize that sublethal effects may be as important or even more important than mortality, and that initial insecticide deposits quickly degrade over time leading to prevailing sublethal exposure. Furthermore, although the target of control is limited to few species, non-target species will be exposed and as such need to be factored into consideration. Thus, these biases in studies of botanical insecticides incur in knowledge gaps with potential consequences for the practical use of these compounds as pest management tools.

Insecticide use remains controversial, and subjected to increasing environmental and health concerns, even when recent insecticide groups are considered. Neonicotinoids and even bioinsecticides are in the forefront of discussions regarding their nontarget safety. The ubiquitous focus on the lethal effects of insecticides on nontarget species has been expanding to sublethal effects, as sublethal exposure extends for a longer time and affects a broader range of (nontarget) species. Here we explored the lethal and sublethal effects of a lambda-cyhalothrin + thiamethoxan mixture, the neonicotinoid imidacloprid, and the bioinsecticide azadirachtin on the egg parasitoid Telenomus podisi Ashmead, an important parasitoid of stink bug Euschistus heros (F.), a key soybean pest in neotropical America. Contact with dry insecticide residue on glass surface and (parasitized and healthy) host egg immersion exposure bioassays were performed, assessing their acute lethal effects, and their potential sublethal impairment of parasitism, adult emergence, and fertility of the egg parasitoid. Both imidacloprid and the insecticide mixture exhibited high acute lethal activity toward the parasitoid under contact with dry insecticide residue. These insecticides compromised parasitism and wasp emergence when exposure took place before parasitism. In contrast, azadirachtin did not affect adult survival. However, this bioinsecticide compromised parasitism and progeny production, impairing the female parasitoid reproductive potential. Our results indicate strong negative effects of imidacloprid, and specially of the mixture lambda-cyhalthrin + thiamethoxan. However, even azadirachtin, which exhibited low acute lethality, exhibited significant negative sublethal effects on parasitism and population growth of egg parasitoid, cautioning against their use and the need of semifield and field assessments to confirm such an impact.

For over a century, the role of acoustic communication in the sensory ecology of bark beetles (Scolytinae) has been recognized. However, their ‘world of sound’ remains largely unexplored. Here, we review 153 years of bark beetle bioacoustics publications to summarize current knowledge, identify gaps and suggest future research directions. Our survey identified 117 publications covering 170 species. Morphological reports revealed five stridulatory organs across 125 species, with elytro‐tergal, gular‐prosternal and vertex‐pronotum mechanisms being the most prevalent for sound production. However, confirmed sound recordings exist for only 40 species. Acoustic signalling in adults is proposed to function in avoiding enemies, pair formation, sexual selection and spacing, while in juveniles, vibratory communication is proposed for gallery spacing. However, experimental evidence supporting these functions is lacking. Acoustic sensory organs remain unidentified, and comprehension of signal transmission—whether through airborne sounds or solid‐borne vibrations (or both)—is limited. Bioacoustic technologies have emerged as tools for potential management practices and are also discussed. Based on these findings, we recommend three directions for future research: (1) characterize acoustic morphology and behaviours in more species, particularly unrepresented taxa, with recordings in various contexts, preferably under natural conditions; (2) test hypotheses to explain the functions of acoustic communication through experimental and comparative phylogenetic methods and (3) investigate how sounds or vibrations are transmitted and received through behavioural and neurophysiological experiments. Advancements in bark beetle acoustic sensing and communication research will enhance our understanding of their sensory ecology and facilitate potential control measures of these fascinating insects.