AProceedings platypodine of new the toHawaiian Oahu aEndntomological Hawaii isla ndsSociety (2017) 49:51–57 51

New Records and Accounts

A Second Adventive Species of Pinhole-borer on the Islands of Oahu and Hawaii (Coleoptera: Curculionidae: Platypodinae)

Conrad P.D.T. Gillett and Daniel Rubinoff Entomology Section, Department of Plant and Environmental Protection Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, 3050 Maile Way, Honolulu, HI 96822, U.S.A. [email protected]; [email protected]

Key words: New record, Euplatypus parallelus, Platypodini, ambrosia beetle, Hawaiian Islands

The Platypodinae is presently classi- podines are not host-specific, and are able fied as a subfamily of the weevil family to inoculate and farm ambrosia fungus in Curculionidae (Alonso-Zarazaga and Lyal the wood of many different tree families 1999, Bouchard et al. 2011), and contains (Jordal 2014). Some species of Platypo- more than 1400 species described in 34 dinae can be important pests of forests genera and four tribes, occurring primar- and plantations. Although healthy trees ily in tropical and subtropical regions are not generally attacked, stressed plants (Wood 1993). It was traditionally treated and recently felled timber can be infested as a close relative of the Scolytinae, which by the beetles (and their associated fungi); are the most diverse subfamily of special- the resulting discoloured galleries reduce ized wood-boring beetles. However, the the value of the lumber (Beaver 2013). phylogenetic position of Platypodinae Hitherto, only a single, exotic species of within the weevils remains unclear, and Platypodinae has been widely recorded in recent molecular phylogenies (e.g., Gillett the literature from the Hawaiian Islands: et al. 2014) now indicate only a distant Crossotarsus externedentatus (Fairmaire relationship with Scolytinae, and likely 1849) (Nishida 2002), a species that is independent origins of the wood-boring widespread in tropical forests around the specialization. Because of their habit of globe (Wood and Bright 1992). A second boring circular entrance holes in dead species, Euplatypus parallelus (Fabricius wood, and on account of their elongate 1801), was first recorded for the state (as form, platypodines have been known by Platypus parallelus) in an unpublished the common name of “pinhole borers.” report from the island of Maui (Howarth The vast majority of platypodine spe- and Preston 2002), then subsequently in cies are xylomycetophagous, cultivating an updated, published report, where it was symbiotic ‘ambrosia’ fungi within their listed as uncommon (Howarth, Preston, galleries, as an obligate food source for and Pyle 2012), but has not been widely their larvae (Jordal 2015, Kirkendall et reported nor included in the current Ha- al. 2015), and therefore are also termed waiian Terrestrial Arthropod Checklist “ambrosia beetles.” A consequence of the (Bishop Museum 2017). We can now ambrosia-farming habit is that most platy- formally record E. parallelus from the 52 Gillett and Rubinoff island of Oahu, through recent fieldwork Hawaii, Hawaii, Captain Cook, there during the second half of 2017, and 02.xi.2014, leg. Noel Dickinson – 1 female from the island of Hawaii, through iden- specimen (UHH). tification of preserved specimens. A total Hawaii, Hawaii, Panaewa, 06.ix – of 22 Hawaiian specimens were studied, 04.x.2013, leg. J. Zarders: Ethanol trap – 2 as follows. male and 1 female specimens (UHH). In addition to the studied specimens, Material Examined we cite here the records published in the Newly collected specimens are depos- Bishop Museum Technical Report 58, on ited in the University of Hawaii Insect a survey of arthropods from the environs Museum (UHIM). Specimens were also of Kahului airport, Maui (Howarth and located in the collection of the State of Ha- Preston 2002) and subsequently published waii Department of Agriculture (HDOA), in a report (Howarth, Preston, and Pyle Honolulu, and in the collection of the Uni- 2012) containing a photograph of a male versity of Hawaii, Hilo (UHH) (examined specimen of E. parallelus. by photographs). Digital photographs of Hawaii, Maui, Kahului airport envi- a pair of representative specimens of E. rons, Kanaha Pond Wildlife Sanctuary, parallelus from Oahu (Figure 1A and B) 20° 53' 57" N, 156° 27' 14" W, 03.iii.2000, were taken with a Nikon D-7100 DSLR F.G. Howarth, D.J. Preston, K. Martz, F. camera mounted on an Olympus stereomi- Starr, and J.E. Dockall: Mercury vapor croscope. The images were subsequently light, keawe (Prosopis pallida), Sesuvium, focus-stacked using Helicon Focus run- native shrubs. ning on an iMac computer. Hawaii, Maui, Kahului airport envi- Hawaii, Oahu, Waianae Mountains, rons, Aalele dump area, 20° 53' 35" N, Palikea Ridge trail, 21° 23' 60" N, 158° 156° 26' 38"W, 15 masl, 28.iii.2000, F.G. 5' 60" E, 860 masl, 24.vii.2017, leg. and Howarth, D.J. Preston, G.A. Samuelson, F. det. C.P.D.T. Gillett: Lindgren-funnel trap Starr, K. Martz, and J.E. Dockall: Mercury baited with ethanol lure – 1 female speci- vapor light, keawe woodland (Prosopis men (UHIM). Same data as above, except pallida, Leucaena, Cenchrus, etc.). 13.viii.2017 – 1 male specimen (UHIM). Hawaii, Maui, Kahului airport en- Hawaii, Oahu, Honolulu, Manoa, virons, near Kanaha Pond, near South University of Hawaii campus, roof of gate, 20° 53' 36" N,156° 27' 05.2" W, Gilmore Hall, 21° 18' 0" N, 157° 48' 36" 31.v.2000, D.J. Preston, J.E. Dockall, K. E, 30 masl, 07.ix.2017, leg. M. Logan and Martz and F. Starr: Mercury vapor light, C. Doorenweerd, det. C.P.D.T. Gillett: keawe woodland (Prosopis pallida). Mercury vapor light trap – 1 male and 2 Hawaii, Maui, Kahului airport envi- female specimens (UHIM). rons, between Kanaha drainage canal and Hawaii, Hawaii, Kealakekua, T-shirt factory building, 20° 53' 51" N,156° 11.ix.2003, leg. M. Ohta, det. G.A. Samu- 26' 54" W, 04.vi.2000, F.G. Howarth, D.J. elson: “Boring into dying trunk of pink Preston, J.E. Dockall, R. Takumi and G.A. shower,” Cassia javanica (Fabaceae) – 9 Samuelson: Mercury vapor and blacklight, male, and 2 female specimens (HDOA). Leucaena-keawe scrub, mixed weeds. Hawaii, Hawaii, Honomalino, The dominant trees in the immediate viii.1988, leg. C. Robb, det. G.A. Samuel- vicinity of where the specimens were son: “ex Macnut tree trunk,” Macadamia collected at Palikea (Oahu) consisted sp. (Proteaceae) – 2 male specimens of the exotic Casuarina equisetifolia (HDOA). (ironwood), and Araucaria heterophylla A platypodine new to Oahu and Hawaii islands 53

Figure 1. Species of Platypodinae recorded from Hawaii. (A) Male and (B) female of Euplatypus parallelus collected on Oahu in September 2017. (C) Male and (D) female of Crossotarsus externedentatus collected on Hawaii. Specimens deposited in UHIM. Photographs by C.P.D.T. Gillett. 54 Gillett and Rubinoff (Cook pine), with some scattered native Metrosideros polymorpha (ohia lehua). The vegetation in the vicinity of the University of Hawaii campus consists of a broad mix of pantropical invasive and ornamental species (http://manoa.hawaii. edu/landscaping/plantmap.php).

Diagnosis and Identification 1 Both species of platypodine presently occurring on Hawaii are sexually dimor- phic. The males are easily identified by their projecting elytral apices, which have very distinctive species-specific morphology, allowing them to be easily distinguished from each other. The api- cal quarter of the elytra of E. parallelus males is rather abruptly narrowed, with the external elytral apices projected into comparatively blunt, and slightly2 divergent teeth (Figure 1A). In contrast, the apical quarter of the elytra of male C. externe- dentatus is only gradually, and com- paratively less narrowed, with the external elytral apices projected into longer and sharper, slightly convergent teeth (Figure 1C). Both sexes can be distinguished by the following characters, modified from the dichotomous key in Wood (1993): Euplatypus parallelus (Figure 1A and B): Metasternum and metepisternum near metacoxa usually weakly or not3 impressed for reception of femur; anterior4 marginFigure 2. of Figure 2. Map showing localities where impressed area not carinate or armed by Euplatypus parallelus has been recorded row of small spines; surface of impressed on the islands of (A) Oahu, (B) Maui, and area with some setae present. (C) Hawaii. Collection localities indicated Crossotarsus externedentatus (Figure by black stars. 1C and D): Metasternum and metepister- num near metacoxal impressed for recep- tion of femur; anterior margin of impressed dissimilar localities (Figures 2 and 3) area either carinate or armed by series on Oahu, namely, a forested mountain- of small spines (sometimes absent in fe- ous area containing both native and males); surface of impressed area glabrous. introduced plants, and a distinctly urban environment (surrounded by forested Discussion hills) harbouring almost uniquely exotic Because E. parallelus was recently plants, it is reasonable to conclude that found at two widely separated, and highly the species is already well established on A platypodine new to Oahu and Hawaii islands 55

1 Figure 3. Locations where Euplatypus parallelus has been collected on the island of Oahu. (A) The forested hillside on Palikea Trail, in the Waianae mountains. (B) Lindgren-funnel trap in place at the collecting locality. (C) View of the forested Manoa valley hillsides surrounding the university campus. (D) Gilmore Hall at the University of Hawaii at Manoa campus, Honolulu. Photographs by C.P.D.T. Gillett.

Oahu. That E. parallelus has not appar- rapidly spread in the Oriental Region, ently been recorded again on Maui since probably due to the intensification of the 2000 is somewhat intriguing, especially international trade in timber following the given the renewed interest and efforts in Second World War (Beaver 2013), and is sampling and monitoring bark beetles now very widely distributed there. There- since the arrival of the coffee berry borer fore, the present discovery of E. parallelus (Hypothenenus hampei Ferrari 1867) as in the Hawaiian Islands is not surprising, an invasive pest of coffee on Hawaii in and is possibly evidence of a continua- 2010 (Burbano et al. 2011) and the advent tion of its rapid advance through Asia; of the fungal disease rapid ohia death, it should be expected in due course on which may be at least partially vectored other Hawaiian Islands. In the continental by bark beetles. United States, E. parallelus was recently Although E. parallelus is native to recorded from Texas (Atkinson and Riley the Neotropical Region, it is now one of 2013), and has otherwise been previously the most widespread platypodines, with reported from Florida (Atkinson and Peck, a pantropical distribution that includes 1994) and California (Atkinson 2017). introductions to Africa, Madagascar, Aus- Euplatypus parallelus is highly polyph- tralia and tropical Asia (Wood and Bright agous, having been recorded from more 1992; Beaver 1999, 2013). It has recently than 60 host species, in 21 plant families in 56 Gillett and Rubinoff Africa alone, including both broad-leaved lection and reports, and Curtis Ewing and coniferous trees (Schedl 1965). These (UH) who supplied additional records have included species of considerable and specimen photographs. We are also commercial value such as Eucalyptus, grateful to the Hawaiian coffee industry rubber, pines, and tropical fruit trees (Bea- and the HDOA for their support, and ver 2013). Whilst the majority of attacks for two anonymous reviewers’ critical are secondary, upon living trees that have comments. Funding was provided by been previously stressed by fire, drought, the College of Tropical Agriculture and pathogens, or other causes (Beaver 2013), Human Resources (CTAHR), University primary attacks on apparently healthy of Hawaii at Manoa, USDA Cooperative trees are not unknown (e.g., Bumrungsri State Research, Education and Extension et al. 2008). In some cases, an association project HAW00942-H, administered by has been made between attacks by beetles, CTAHR, University of Hawaii. the presence of pathogenic fungi, and the subsequent death of trees, although the Literature Cited precise role of E. parallelus as a vector Atkinson, T.H., and S.B. Peck. 1994. An- of pathogenic fungi in such cases remains notated checklist of the bark and ambrosia unclear (Beaver 2013). beetles (Coleoptera: Platypodidae and Sco- As yet, little is known of the preferred lytidae) of tropical southern Florida. Atkinson, T.H., and E.G. Riley. 2013. Atlas plant host(s) for E. parallelus in the and checklist of the bark and ambrosia Hawaiian Islands beyond the label data beetles of Texas and Oklahoma (Curculioni- on specimens collected in Hawaii Island dae: Scolytinae and Platypodinae). Insecta from Macadamia sp. (Proteaceae) and Mundi 0292: 1-46. Cassia javanica (Fabaceae). Because Atkinson, T.H. 2017, October 5. Bark and of the highly polyphagous nature of the ambrosia beetles. Retrieved from http:// species elsewhere in its range, there ex- www.barkbeetles.info. ists a possibility that E. parallelus may Alonso-Zarazaga, M.A., and C.H.C. Lyal. 2009. A catalogue of family and genus group potentially develop into a pest of either the names in Scolytinae and Platypodinae with already fragile indigenous and endemic nomenclatural remarks (Coleoptera: Curcu- Hawaiian flora, or a pest of commercially lionidae). Zootaxa 2258: 1–134. or ornamentally important introduced Beaver, R.A. 1999. New records of ambrosia trees, or both. Therefore, an awareness of beetles from Thailand (Coleoptera: Platy- the presence of this potential pest on the podidae). Serangga 4: 29–34. Hawaiian Islands, together with vigilant Beaver, R.A. 2013. The invasive neotropical monitoring is recommended, to both ambrosia beetle Euplatypus parallelus establish its present area of occupancy, (Fabricius, 1801) in the Oriental region and its pest status (Coleoptera: Curculionidae: and in order to keep track of any future Platypodinae). Entomologist’s Monthly expansion in distribution. Magazine 149: 143–154. Bishop Museum. 2017. Hawaiian Ter- Acknowledgments restrial Arthropod Checklist; http:// We thank Mitchel Bradley, Camiel hbs.bishopmuseum.org/checklist/query. Doorenweerd, and Christine Elliott (all asp?grp=Arthropod; (Accessed October UHIM) for assistance in the field and 24, 2017). for collecting specimens. We are also Bouchard, P., Y. Bousquet, A.E. Davies, M.A. Alonso-Zarazaga, J.F. Lawrence, indebted to Thomas Anuhealii for ac- C.H.C. Lyal, A.F. Newton, C.A.M. Reid, cess to the Palikea trail, Janis Matsunaga M. Schmitt, S.A. Ślipiński, and A.B.T. (HDOA) for access to the HDOA col- Smith. 2011. Family-group names in Cole- A platypodine new to Oahu and Hawaii islands 57 optera (Insecta). Zookeys 88: 1–972. Jordal, B.H. 2014. Platypodinae, pp. 358–364. Bumrungsri, S., R. Beaver, S. Phongpaichit, In R. Leschen and R. Beutel (eds.), Hand- and W. Sittichaya. 2008. The infestation book of Zoology. 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