Host plant volatiles play a key role in mediating plant–herbivore interactions. How an array of host plant volatiles guides host preference and attraction in the invasive polyphagous Lycorma delicatula (White), the spotted lanternfly (SLF), is largely unknown. A pernicious phloem feeder, SLF feeds on over 70 species of plants, some with high economic impact. To aid the development of detection and monitoring tools for SLF, we used a two-choice olfactometer to compare 14 host plant species for attraction, first to a blank control, and then to their preferred host Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), tree-of-heaven. SLF were significantly attracted to seven host plants compared to a blank control, but no host plant was more attractive than tree-of-heaven. We then used electroantennographic detection (EAD) to screen select host plants for EAD active compounds, hypothesizing that EAD-active plant volatiles act as kairomones and mediate SLF attraction to host plants. Out of 43 unique antennal responses, 18 compounds were identified and tested individually for attraction in a two-choice olfactometer against a blank control and then against methyl salicylate, the current best attractant. Eleven compounds were significantly attractive, and one, sulcatone, was more attractive than methyl salicylate. Blends of kairomones were then tested for attraction, revealing five blends that were significantly more attractive than methyl salicylate, and could be developed into lures for field testing.The presence of these kairomones in volatile profiles of 17 plant species is described.These findings support the hypothesis that the identified volatiles act as kairomones and function in attraction to host plants.

The leaf beetle Diorhabda carinulata Desbrochers (Coleoptera: Chrysomelidae) was introduced into the United States in 1999 for classical biological control of the exotic woody invader saltcedar (Tamarix spp. L. [Caryophyllales: Tamaricaceae]). The recent southern expansion of the range of D. carinulata in the United States has precipitated conflict between proponents of biological control of Tamarix and those with concerns over habitat conservation for avian species. Several semiochemicals that mediate aggregations by this species have been reported, but no repellent compounds have been recorded thus far. We now report a repellent compound, 4-oxo-(E)-2-hexenal, induced by adult D. carinulata feeding on saltcedar foliage. Collection of headspace volatiles, gas chromatography mass spectrometry, and electroantennographic analyses identified 4-oxo-(E)-2-hexenal as an insect-induced compound that is antennally active. Behavioral and exposure assays were conducted to test for repellency and toxicity in adults and larvae. Headspace volatiles were also collected from adult males exposed to 4-oxo-(E)-2-hexenal to determine the impact exposure might have on the emission of the aggregation pheromone. 4-Oxo-(E)-2-hexenal elicited electrophysiological responses in adults of both sexes. Behavioral responses indicated repellency across multiple doses for reproductive D. carinulata adults but not in nonreproductive adults. Exposure assays indicated altered behaviors in first instar larvae and adults, but not in third instar larvae. Collection of headspace volatiles indicated that exposure to 4-oxo-(E)-2-hexenal did not alter emission of the D. carinulata aggregation pheromone by adult males. The continued development and field deployment of this repellent compound may provide a new tool for the management of D. carinulata.

The invasive weed Rumex confertus Willd. (mossy sorrel) is eaten and severely defoliated by oligophagous Gastrophysa viridula Deg. (dock leaf beetle) and Gastrophysa polygoni L. (knotweed leaf beetle). The most popular methods of plant protection involve the application of chemicals, but such methods often require repeated chemical treatments. Aromatic plants may constitute an eco-friendly alternative strategy owing to their repellent properties. To date, single compounds have been tested rather than blends; however, there is a need to investigate mixtures of compounds, because insects are subjected to blends of odors derived from their surrounding environments. The aim of the current study was to investigate behavioral responses of the dock leaf beetle and knotweed leaf beetle to a blend of synthetic plant volatile organic compounds. Plants were treated with standard repellents (a blend of volatile organic compounds) at two different concentrations (10 ng min^–1 and 1,000 ng min^–1). For further experiments, four rates (1 ng min^–1, 10 ng min^–1, 100 ng min^–1, and 1,000 ng min^–1 in 50 µl) were evaluated using a 4-way olfactometer. Leaf beetles of both sexes were repelled by the highest three concentrations tested. Female dock leaf beetles were also repelled by the lowest concentration tested, where individual components could have occasionally attracted insects. These results indicate a difference in responses to individual compounds and mixtures of compounds.

Despite its broad host range, the spotted lanternfly Lycorma delicatula (White), is known to have a marked preference for Ailanthus altissima. However, whether this polyphagous phloem feeder can complete its life cycle in the absence of A. altissima is unknown. We examined the performance of L. delicatula with and without access to A. altissima by tracking development, survival, host tree species association, and oviposition in large enclosures planted with Salix babylonica and Acer saccharinum along with either A. altissima or Betula nigra. We monitored enclosures from late May 2019 through June 2020. Lycorma delicatula survival was slightly higher in enclosures with A. altissima and 50% of individuals in A. altissima enclosures reached the adult stage ∼6.5 d earlier than in enclosures without A. altissima. In the presence of A. altissima, nymphs were most frequently observed on this host while adults were found at similar frequencies on A. altissima and A. saccharinum. In the absence of A. altissima, nymphs were most frequently associated with S. babylonica and A. saccharinum, while adults were most often found on A. saccharinum. Females laid a total of 46 and 6 egg masses in enclosures with and without A. altissima, respectively, before freezing temperatures killed the remaining adults. The proportion of eggs that hatched per egg mass did not differ between treatments. Although L. delicatula can complete development and reproduce on other host species without access to A. altissima, fitness was reduced. These findings have implications for management that relies exclusively on treatment of A. altissima.

Bees (Family Apidae) hold a key role as pollinators in a wide range of angiosperm communities. South America suffered strong modifications during the last decade due to increasing anthropic activities and the expansion of agricultural areas, particularly the boom of soybean. The goal of this research was to know the current diversity of bees in South and Low Littoral regions in Uruguay. Specimens were collected in the seasons 2015–2016 and 2016–2017 on natural meadows, cultivated grasslands, soybean fields, among others flowering communities. Collected specimens were classified following taxonomic keys. Forty-five bee species or taxa were distinguished belonging to the subfamilies Megachilinae (11), Apinae (22), Halictinae (7), Colletinae (2), and Andreninae (3). Most taxa were classified up to genus and 14 to species level. Bee diversity was higher for the South region, with traditional agriculture and rangelands, than that of the Low Littoral region where an increasing agricultural land use took place during the last decade, particularly soybean. In addition, this research aimed to study the presence of native bees and the introduced Apis mellifera (Apinae) in a soybean field at four transects located at 0, 50, 100, and 200 m from the crop border in both seasons. Native bee species were only present at 0 and 50 m, pointing to the relevance of natural edge plant communities for their preservation.This is the first survey on native bee diversity in Uruguay to be regarded as a baseline and the setup of conservation strategies.

Embioptera display the unique ability to spin silk with their front feet to create protective domiciles. Their body form is remarkably uniform throughout the order, perhaps because they all live within the tight confines of silken tubes. This study contributes to an understanding of the ecology of Embioptera, an order that is rarely studied in the field. We conducted a census to quantify the habitats of two species with overlapping distributions on the tropical island of Trinidad in a search for characteristics that might explain their distinct ecologies. One species, Antipaluria urichi (Saussure) (Embioptera: Clothodidae), lives in larger colonies with more expansive silk in habitats throughout the island, especially in the rainforest of the Northern Range Mountains. The other, Pararhagadochir trinitatis (Saussure) (Embioptera: Scelembiidae), was found only in lowland locations. We quantified silk-spinning behavior and productivity of the two species and found that A. urichi spins thicker silk sheets per individual and emphasizes spin-steps that function to create a domicile that is more expansive than that produced by P. trinitatis. Their silks also interact differently when exposed to water: the smaller-diameter silk fibers of P. trinitatis form more continuous films on the surface of the domicile after being wetted and dried than that seen in A. urichi silk. This tendency gives P. trinitatis silk a shiny appearance in the field compared to the more cloth-like silk of A. urichi. How these silks function in the field and if the differences are partially responsible for the distinct distributions of the two species remain to be determined.

Declines among species of insect pollinators, especially butterflies, has garnered attention from scientists and managers. Often these declines have spurred governments to declare some species as threatened or endangered. We used existing presence–absence data from surveys for the threatened Dakota skipper Hesperia dacotae (Skinner) to build statistical maps of species presence that could be used to inform future monitoring designs. We developed a hierarchical Bayesian modeling approach to estimate the spatial distribution and temporal trend in Dakota skipper probability of presence. Our model included a spatial random effect and fixed effects for the proportion of two grassland habitat types: those on well-drained soils and those on poorly drained soils; as well as the topographic slope. The results from this model were then used to assess sampling strategies with two different monitoring objectives: locating new Dakota skipper colonies or monitoring the proportion of historically (pre-2000) extant colonies. Our modeling results suggested that the distribution of Dakota skippers followed the distribution of remnant grasslands and that probabilities of presence tended to be higher in topographically diverse grasslands with well-drained soils. Our analysis also showed that the probability of presence declined throughout the northern Great Plains range. Our simulations of the different sampling designs suggested that new detections were expected when sampling where Dakota skippers likely occurred historically, but this may lead to a tradeoff with monitoring existing sites. Prior information about the extant sites may help to ameliorate this tradeoff.