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BackgroundInvasive species threaten the productivity and stability of natural and managed ecosystems. Predicting the spread of invaders, which can aid in early mitigation efforts, is a major challenge, especially in the face of climate change. While ecological niche models are effective tools to assess habitat suitability for invaders, such models have rarely been created for invasive pest species with rapidly expanding ranges. Here, we leveraged a national monitoring effort from 543 sites over 3 years to assess factors mediating the occurrence and abundance of brown marmorated stink bug (BMSB, Halyomorpha halys), an invasive insect pest that has readily established throughout much of the United States.ResultsWe used maximum entropy models to estimate the suitable habitat of BMSB under several climate scenarios, and generalized boosted models to assess environmental factors that regulated BMSB abundance. Our models captured BMSB distribution and abundance with high accuracy, and predicted a 70% increase in suitable habitat under future climate scenarios. However, environmental factors that mediated the geographical distribution of BMSB were different from those driving abundance. While BMSB occurrence was most affected by winter precipitation and proximity to populated areas, BMSB abundance was influenced most strongly by evapotranspiration and solar photoperiod.ConclusionOur results suggest that linking models of establishment (occurrence) and population dynamics (abundance) offers a more effective way to forecast the spread and impact of BMSB and other invasive species than simply occurrence-based models, allowing for targeted mitigation efforts. Implications of distribution shifts under climate change are discussed. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Target and non-target Rhagoletis Loew, 1862 (Diptera: Tephritidae) flies trapped in surveys can provide new information on fly abundances, ecologies, and distributions. Here, data from surveys for native R. indifferens Curran, 1932 in non-commercial sweet cherry trees and non-native R. pomonella (Walsh, 1867) in non-commercial apple, crabapple, and hawthorn trees in central Washington State, U.S.A. were used to determine relative abundances of target and non-target Rhagoletis on traps and to test the hypotheses that fly abundances are site, tree type, and seasonal period dependent. Rhagoletis indifferens was the most abundant Rhagoletis in cherry trees. Non-native R. completa Cresson, 1929 was the most abundant Rhagoletis caught in R. pomonella host trees, with overall results suggesting it is the most numerous and/or dispersive Rhagoletis in central Washington. With support from the literature, we infer that: R. pomonella is less tolerant of arid central Washington summers than R. completa, native R. zephyria Snow, 1894, R. indifferens, and native R. basiola (Osten Sacken, 1877); Rhagoletis species diversity is lower in suburban than rural habitats due to the predominant host plants present; all fly species disperse annually at similar relative abundances, resulting in geographic range expansions over a few generations; and peak seasonal dispersal of flies to non-natal tree species coincides with natal host fruit development, resulting in colonization of new fruiting host patches. Differential fly tolerances of arid summer climates due to adaptation or preadaptation, habitat type, and annual and seasonal dispersal patterns could explain abundances and distributions of native and non-native Rhagoletis species in central Washington. [ABSTRACT FROM AUTHOR]

The Japanese beetle, Popillia japonica (Newman, 1841) (Coleoptera: Scarabaeidae), was first detected in southern Washington State in 2020. Widespread trapping efforts ensued, and over 23,000 individuals were collected in both 2021 and 2022 in this region known for specialty crop production. The invasion of Japanese beetle is of major concern as it feeds on over 300 plant species and has shown an ability to spread across landscapes. Here, we created a habitat suitability model for Japanese beetle in Washington and used dispersal models to forecast invasion scenarios. Our models predict that the area of current establishment occurs in a region with highly suitable habitat. Moreover, vast areas of habitat that are likely highly suitable for Japanese beetle occur in coastal areas of western Washington, with medium to highly suitable habitat in central and eastern Washington. Dispersal models suggested that the beetle could spread throughout Washington within 20 years without management, which justifies quarantine and eradication measures. Timely map-based predictions can be useful tools to guide management of invasive species while also increasing citizen engagement to invaders. [ABSTRACT FROM AUTHOR]