1190 © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. Ecology and Behavior Vertical Distribution and Daily Flight Periodicity of Ambrosia Beetles (Coleoptera: Curculionidae) in Florida Avocado Orchards Affected by Laurel Wilt Octavio Menocal, 1,3 Paul E. Kendra, 2 Wayne S. Montgomery, 2 Jonathan H. Crane, 1 and Daniel Carrillo 1 1 Tropical Research & Education Center, University of Florida, 18905 SW 280th Street, Homestead, FL 33031-3314, 2 USDA-ARS, Subtropical Horticulture Research Station, 13601 Old Cutler Road, Miami, FL 33158-1857, and 3 Corresponding author, e-mail: omenocal18@ufl.edu Subject Editor: Brian Sullivan Received 14 November 2017; Editorial decision 2 February 2018 Abstract Ambrosia beetles have emerged as signifcant pests of avocado ((Persea americana Mill. [Laurales: Lauraceae])) due to their association with pathogenic fungal symbionts, most notably Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), the causal agent of the laurel wilt (LW) disease. We evaluated the interaction of ambrosia beetles with host avocado trees by documenting their fight height and daily fight periodicity in Florida orchards with LW. Flight height was assessed passively in three avocado orchards by using ladder-like arrays of unbaited sticky traps arranged at three levels (low: 0–2 m; middle: 2–4 m; high: 4–6 m). In total, 1,306 individuals of 12 Scolytinae species were intercepted, but six accounted for ~95% of the captures: Xyleborus volvulus (Fabricius) (Coleoptera: Curculionidae), Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae), Euplatypus parallelus (Fabricius) (Coleoptera: Curculionidae), Xyleborus bispinatus Eichhoff (Coleoptera: Curculionidae), Xyleborus af fnis Eichhoff (Coleoptera: Curculionidae), and Hypothenemus sp. (Coleoptera: Curculionidae). The primary vector of R. lauricola, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae), was not detected. Females of X. volvulus showed a preference for fight at low levels and X. bispinatus for the low and middle levels; however, captures of all other species were comparable at all heights. At a fourth orchard, a baiting method was used to document fight periodicity. Females of X. saxesenii and Hypothenemus sp. were observed in fight 2–2.5 h prior to sunset; X. bispinatus, X. volvulus, and X. af fnis initiated fight at ~1 h before sunset and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae) at 30 min prior to sunset. Results suggest that ambrosia beetles in South Florida fy near sunset (when light intensity and wind speed decrease) at much greater heights than previously assumed and have species-specifc patterns in host-seeking fight. Key words: abiotic factor, flight height, insect dispersal, Scolytinae, wind speed Flight is critical to the biology and ecological success of many insect species. Flight assists insects in various ways, including location of mates, evasion of predators, utilization of food resources, and colo- nization of new habitats (Sane 2003). In the case of ambrosia beetles (Coleoptera: Curculionidae: Scolytinae and Platypodinae) dispersal fight is used by females to locate new host trees suitable for coloni- zation and cultivation of their symbiotic fungi, the only nutritional source required to sustain new beetle colonies (Farrell et al. 2001). Most ambrosia beetles are not considered pests; they typically target stressed or dying trees and their symbiotic fungi are not phy- topathogens. However, the recent incursion of exotic beetles and their pathogenic fungal symbionts into the United States has raised the status of some ambrosia beetles to that of economically important forest and agricultural pests (Hulcr and Dunn 2011). Over the past 5 yr, avocado (Persea americana Mill.) trees in southern Florida have been affected by Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), a fungal symbiont of ambrosia beetles and the causal agent of laurel wilt (LW) disease, recently reviewed by Ploetz et al. (2017a). The redbay ambrosia bee- tle (X. glabratus) is the primary vector of R. lauricola in natural ecosystems in the southeastern United States (Fraedrich et al. 2008, Hughes et al. 2015). This beetle brought R. lauricola to Florida avo- cado groves, most likely due to the attractive kairomones emitted by this host tree species (Kendra et al. 2011, 2014). However, avocado appears to be a poor reproductive host for X. glabratus (Brar et al. 2013). Consequently, X. glabratus is rare in commercial avocado Journal of Economic Entomology, 111(3), 2018, 1190–1196 doi: 10.1093/jee/toy044 Advance Access Publication Date: 8 March 2018 Research Article Downloaded from https://academic.oup.com/jee/article/111/3/1190/4924705 by guest on 26 July 2022