In support of a comprehensive update to the checklist of the moths of North America, we attempt to determine the status of 151 species of Tortricidae present in North America that may be Holarctic, introduced, or sibling species of their European counterparts. Discovering the natural distributions of these taxa is often difficult, if not impossible, but several criteria can be applied to determine if a species that is present in both Europe and North America is natively Holarctic, introduced, or represented by different but closely related species on each continent. We use DNA barcodes (when available), morphology, host plants, and historical records (literature and museum specimens) to make these assessments and propose several taxonomic changes, as well as future areas of research. The following taxa are raised from synonymy to species status: Acleris ferrumixtana (Benander, 1934), stat. rev.; Acleris viburnana (Clemens, 1860), stat. rev.; Acleris pulverosana (Walker, 1863), stat. rev.; Acleris placidana (Robinson, 1869), stat. rev.; Lobesia spiraeae (McDunnough, 1938), stat. rev.; and Epiblema arctica Miller, 1985, stat. rev. Cydia saltitans (Westwood, 1858), stat. rev., is determined to be the valid name for the “jumping bean moth,” and Phiaris glaciana (Möschler, 1860), comb. n., is placed in a new genus. We determine that the number of Holarctic species has been overestimated by at least 20% in the past, and that the overall number of introduced species in North America is unexpectedly high, with Tortricidae accounting for approximately 23–30% of the total number of Lepidoptera species introduced to North America.

Until recently, the Old World bollworm (OWB) Helicoverpa armigera (Hübner) and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) were geographically isolated. Both species are major pests of agricultural commodities that are known to develop insecticide resistance, and they now coexist in areas where H. armigera invaded the Americas. This is the first study to compare the susceptibility of the two species to conventional insecticides. The susceptibility of third instar H. armigera and H. zea larvae to indoxacarb, methomyl, spinetoram, and spinosad was determined using a diet-overlay bioassay in a quarantine laboratory in Puerto Rico. Mortality was assessed at 48 h after exposure for up to eight concentrations per insecticide. Spinetoram exhibited the highest acute toxicity against H. armigera, with a median lethal concentration (LC₅₀) of 0.11 µg a.i./cm², followed by indoxacarb and spinosad (0.17 µg a.i./cm² for both) and methomyl (0.32 µg a.i./cm²). Spinetoram was also the most toxic to H. zea (LC₅₀ of 0.08 µg a.i./cm²), followed by spinosad (0.17 µg a.i./cm²) and methomyl (0.18 µg a.i./cm²). Indoxacarb was the least toxic to H. zea, with an LC₅₀ of 0.21 µg a.i./cm². These findings could serve as a comparative reference for monitoring the susceptibility of H. armigera and H. zea to indoxacarb, methomyl, spinetoram, and spinosad in Puerto Rico, and may facilitate the detection of field-selected resistance for these two species and their potential hybrids in areas recently invaded by H. armigera.

Invasive insects can cause catastrophic damage to ecosystems and cost billions of dollars each year due to management expenses and lost revenue. Rapid detection is an important step to prevent invasive insects from spreading, but improvements in detection capabilities are needed for bulk collections like those from sticky traps. Here we present a bulk DNA extraction method designed for the detection of Phthorimaea absoluta Meyrick (Lepidoptera: Gelechiidae), an invasive moth that can decimate tomato crops. We test the extraction method for insect specimens on sticky traps, subjected to different temperature and humidity conditions, and among mock insect communities left in the field for up to 21 d. We find that the extraction method yielded high success (>92%) in recovering target DNA across field and lab trials, without a decline in recovery after three weeks, across all treatments. These results may have a large impact on tomato growing regions where P. absoluta is in the early stages of invasion or not yet present. The extraction method can also be used to improve detection capabilities for other bulk insect collections, especially those using sticky traps, to the benefit of pest surveys and biodiversity studies.

Insect crop pests threaten global food security. This threat is amplified through the spread of nonnative species and through adaptation of native pests to control measures. Adaptations such as pesticide resistance can result from selection on variation within a population, or through gene flow from another population. We investigate these processes in an economically important noctuid crop pest, Helicoverpa zea, which has evolved resistance to a wide range of pesticides. Its sister species Helicoverpa armigera, first detected as an invasive species in Brazil in 2013, introduced the pyrethroid-resistance gene CYP337B3 to South American H. zea via adaptive introgression. To understand whether this could contribute to pesticide resistance in North America, we sequenced 237 H. zea genomes across 10 sample sites. We report H. armigera introgression into the North American H. zea population. Two individuals sampled in Texas in 2019 carry H. armigera haplotypes in a 4 Mbp region containing CYP337B3. Next, we identify signatures of selection in the panmictic population of nonadmixed H. zea, identifying a selective sweep at a second cytochrome P450 gene: CYP333B3. We estimate that its derived allele conferred a ∼5% fitness advantage and show that this estimate explains independently observed rare nonsynonymous CYP333B3 mutations approaching fixation over a ∼20-year period. We also detect putative signatures of selection at a kinesin gene associated with Bt resistance. Overall, we document two mechanisms of rapid adaptation: the introduction of fitness-enhancing alleles through interspecific introgression, and selection on intraspecific variation.

The tomato leafminer, Tuta absoluta (Meyrick), is a highly destructive pest of tomatoes, causing damage to leaves, stalks, buds, and fruits. Native to South America, T. absoluta is now found throughout Europe, South Asia, Africa, parts of Central America, and the Caribbean. Adults are small, with a wingspan of approximately one cm and lack distinctive markings, making morphological identification difficult. Larvae are also difficult to identify and resemble those of many other gelechiids. Due to the extensive time spent and expertise required for morphological identification, and the imminent threat to the North American tomato crop, we have developed a rapid molecular test for discriminating individual specimens of T. absoluta using a probe-based real-time polymerase chain reaction (PCR) assay. The assay is able to quickly distinguish T. absoluta from similar-sized moth specimens that are attracted to T. absoluta pheromone lures in the United States and is also able to identify larvae of T. absoluta. Decreased identification time for this critical pest will lead to more rapid identification at ports of entry and allow for more efficient trap screening for domestic monitoring programs.

Bark beetles in the family Curculionidae present a growing hazard to forests worldwide. Like native bark beetles, introduced exotic species can pose a serious threat to North American forests. Ips typographus (Boerner) and Ips sexdentatus (Linnaeus), both native to Europe, are two such pests that have caused widespread forest loss in their native ranges. International trade has led to increased interceptions of Scolytine beetles at ports of entry to the United States. Most intercepted individuals are not identified to species due to lack of expert identifiers, poor specimen quality, or incomplete taxonomy. These same problems affect identification for domestic surveys. Therefore, development of molecular methods for identification of potentially invasive Ips species is essential. Because of the need to scrutinize large numbers of beetles in an efficient manner, we describe a duplex droplet digital PCR (ddPCR) assay to identify I. typographus and I. sexdentatus simultaneously in bulk trap samples containing 500 Scolytinae specimens using a scalable, two-step DNA extraction. This ddPCR method is highly effective for processing the entire contents of beetle traps and identifying these potentially invasive species in a timely and definitive manner. We also describe a nondestructive DNA extraction technique that preserves specimens for morphological identification.