Axiagastus cambelli Distant, 1911

Kment, Petr, Lemaître, Valérie A., Webb, Michael D. & Roca-Cusachs, Marcos, 2025, Revision of the Austro-Oriental shield-bug genus Axiagastus (Hemiptera: Heteroptera: Pentatomidae), with the description of five new species, and taxonomic notes on related genera, Zootaxa 5603 (1), pp. 1-82 : 23-35

Axiagastus cambelli Distant, 1911 and A. marmoratus ( Montrouzier, 1855)

( Figs 44–82)

Pentatoma Marmoratum Montrouzier, 1855: 97 (original description, distribution). Syntypes: Papua New Guinea: Woodlark Island (lectotype in NHMW, see Remarks). New senior subjective synonym.

Axiagastus marmoratus : Stål (1864): 52 –53 (diagnosis, new combination, distribution); Walker (1867): 269 (list, distribution); Stål (1876): 94 (catalogue, distribution); Lethierry & Severin (1893): 170 (catalogue, distribution); Kirkaldy (1909): 126 (catalogue, distribution); Arnold (2011): 42 –43, Fig. 9 (habitus photograph, distribution).

Axiagastus cambelli Distant, 1911a: 345 (original description, plant association, distribution). Syntypes: “ Solomon Islands (W. H. Cambell); Duke of York Island ; Aignan Island (Brit. Mus.)” (BMNH). New junior subjective synonym.

Axiagastus cambelli : Distant (1911b): 384 (list); Wester (1918): 53 (listed as pest); Simmonds (1924): 7, 12 (biology, plant association, distribution); Simmonds (1925): 23, 31 (plant association, distribution); Ferrière (1933): 90, 108 (parasitoids, distribution); Dwyer (1937): 62, 64 (plant association, pest status, distribution); Phillips (1940): 295 –296, 302, 306, 310, 313–315 (biology, plant injury, pest status, distribution); Phillips (1941): 141 (parasitoids); Nixon (1943): 142 (parasitoid); Lepesme (1947): 162 –163 (habitus of adult and larva, biology, plant association, parasitoids, distribution); O’Connor (1950): 68 –69 (parasitoid); Thompson (1950): 21 (parasitoids); Evans (1952): 43, 107 (plant association, pest status, parasitoid, predator); Thompson (1954): 313 (parasitoids, distribution); Phillips (1956): 575 –576 (parasitoid); Cochereau (1964): 1 –23 (egg, larva, biology, plant association, parasitoids, predators, distribution); Tercinier et al. (1964): 9, 11–18, 21–23 (biology, pest status, control, plant association, distribution); Cochereau (1965): 1 –43 (biology, plant association, distribution); Smee (1965): 51, 62: pl. XIII, 64 (habitus drawing of mature larva and adult, biology, plant associations, distribution); Lever (1969): 43 –44, fig. 37 (biology, plant association, pest control, parasitoids, distribution); Cochereau (1972): 91, 97 (plant association, distribution); Baloch (1973): 41 –45 (biology, plant associations, parasitoids, predators, distribution); O’Sullivan (1973): 78 –86 (biology, plant associations, parasitoids, predators, distribution); Stapley (1973): 127 (pest status, associated plant); Stapley (1979): 4 (biological control, predators); Stapley (1980): 5 (biological control, predators); Gagné (1982): 239 (plant associations, pest status, parasitoids, predators); Young (1982): 108 (plant associations, pest status, parasitoids, predators, distribution); Way & Khoo (1992): 484 (predators); Waterhouse (1997): 12, 19, 29 (list of pest species, distribution); Mariau (1998): 270, 274 (biology, plant association, predation); Ikin & Batugal (2004): 40 –41, 47, 100–102 (listed as quarantine pest); Grissell & Smith (2006): 924 (parasitoid); Kakul et al. (2006): 146 (plant association); Grazia & Schwertner (2017): 14 (list of pest species); Rider et al. (2018): 75 (listed as pest), 197, fig. 2.28.I (habitus photograph); Sabbatini Peverieri et al. (2019): 126 (parasitoids); Beattie & Holford (2022): 4 (predators); Exélis et al. (2023): 8 (predators).

Axigastus cambelli (incorrect subsequent spellings): Johns (1941): 4 (parasitoid).

Axiagastus campbelli (incorrect subsequent spelling): Tothill (1929): 9 –15 (descriptions of egg, larva and adult, biology, pest status, control, associated plant, parasitoids, predators, distribution); Lever (1933a): 4 –6 (pest status, plant associations, parasitoids, distribution); Lever (1933b): 3 –4, 6 (descriptions and figures of eggs and larval instars I–V, habitus drawing of adult, biology, plant associations, parasitoids, distribution); Lever (1934b): 139 –141 (parasitoids, distribution); Nixon (1938): 135 (parasitoid, distribution); Lever (1941): 46 (parasitoid); Dumbleton (1957): 22, 27, 35, 39 (plant association, parasitoids); Tercinier et al. (1964): 1, 3, 4, 7 (biology, pest status, control, plant association, distribution); Herting (1971): 82 (parasitoids, predators); Papp (1974): 443, 445 (parasitoid, distribution); Gross (1975): 415 (distribution); Gross (1976): 427 (pest status); Johnson (1991): 232 (parasitoid); Waterhouse (1998): 226, 483, 486, 534 (parasitoid).

Axiasgastus campbelli (incorrect subsequent spellings): Lever (1934a): 2 –3 (parasitoid, distribution).

Axiagastus [no species]: Lever (1933c): 13 (predators).

Coconut Flower-bug: Froggatt (1912): 35: pl. VII, figs 4, 5, 36 (habitus of adult and larva, plant association, distribution).

Type localities. Pentatoma Marmoratum : Papua New Guinea , Woodlark Island , [9°7′S 152°48′E]. Axiagastus cambelli : Solomon Islands .

Type material examined. Pentatoma Marmoratum : Lectotype (here designated) ( Figs 67–70): ♂, “ P. marmoratum (m.) [for “mihi”, meaning “mine”] / Woodlark [hw] // marmorat. [hw] / det. Signoret. [p] // Woodlark. [hw] / Coll. Signoret. [p] // ♂ [p] // LECTOTYPUS / PENTATOMA / MARMORATUM / Montrouzier, 1855 / des. SALINI et al. 2024 [p, red rectangular label] ( NHMW).” The specimen is pinned through the scutellum; left antennomeres III–IV, right antennomere IV, and left metatarsomeres II–III are missing; the detached genital capsule is glued on a separate piece of card attached to the same pin.

Axiagastus cambelli : Lectotype (here designated) ( Figs 37–39): ♂, “Solomon Is. / W. H. Cambell / 1908 [hw] // Axiagastus / cambelli / type Dist. [hw] // Destructive / on Cocoa nuts [sic, hw] // Type [p, red-margined disc] // ♂ [p] / [QR code] / NHMUK010582893 [p] // LECTOTYPUS / AXIAGASTUS / CAMBELLI / Distant, 1911 / des. SALINI et al. 2024 [p, red rectangular label]” ( BMNH). The specimen is pinned through the scutellum; left mesotarsomeres II–III and complete metatarsus, right protarsus, mesotarsomeres II–III and complete hind leg are missing .— Paralectotypes (3♀): 1♀, “Solomon Is. / (W.H. Cambell) / 1908 // destructive to cocoa [sic] nuts // 65 // Distant Coll. / 1911– 383 // syntype [p, blue-margined disc]” ( BMNH) ; 1♀, “Duke York / Isld // Distant Coll. 1911– 383 // syntype [p, blue-margined disc]” ( BMNH) ; 1♀, “ axiagastus cambelli Dist. // 89/89 // syntype [p, blue-margined disc]” ( BMNH) . All the paralectotypes are pinned through the scutellum, and bear the following label: “ PARALECTOTYPUS / AXIAGASTUS / CAMBELLI / Distant, 1911 / des. SALINI et al. 2024 [p, red rectangular label]”.

Additional material examined: AUSTRALIA: Queensland: Queensland , 1♀, no collector, D. Leston det., as Axiagastus cambelli, Salini revid. ( BMNH) . PAPUA NEW GUINEA: Bougainville: Bougainville, H. W. Simmonds , 1♂, 1♀, Pres. By Imp. Bur. Ent. Brit. Mus. 1926-279, B. Uvarov det., as Axiagastus cambelli, Salini revid. ( BMNH) ; Bougainville, Numa Numa , 5223, 1.vi.1956, 1♀, E. S. Brown lgt. ( BMNH) ; Bougainville , 15.vi.1967, 1♀, R.E & R.M. Blackith lgt., B.M.1967-623, Salini det. ( BMNH) ; Buin , 1930, 2♂, 2♀, H. Hediger lgt., P. Kment det. ( NHMB) ; Hill, Soroken, Terr. , Kiety Dist. [= Kieta env.], coconut flower spathe, 1931, 3♂, J.L. E., Pres. by Imp. Inst. Ent. Brit. Mus. 1931-579, Salini det. ( BMNH) ; Kito-Orowa-Plant, 22.vii.1969, 1♂, P. Jolivet lgt., P. Kment det. ( MNHN) ; Numa Numa , 1.vi.1956, 1♂, 4♀, E.S. Brown lgt., Salini det. ( BMNH) . SAMOA: West Samoa, Upolu, Apia (SAMO 1a), 30.vii.–7.viii.2017, 1♂, Wewalka lgt., P. Kment det. ( NHMW) . SOLOMON ISLANDS: Solomo. Ins. , 1♂, ex coll. Holler, P. Kment det. ( NHMW) . Central Province: Savo: Isle of Savo , 27.iv.1922., 1♂, E.A. Armytage lgt., B.M. 1947-284, Salini det. ( BMNH) . Tulagi: Tulagi , 20.iv.1922, 1 ♀ 1 spec. (abdomen missing), E.A. Armytage lgt., B.M. 1947-284, Salini det. ( BMNH) ; Tulagi , male flowers coconut, 25.viii.1933, 6♀, no collector, Salini det. ( BMNH) ; Tulagi , on Hibiscus , not feeding, 2.vii.1933, 1♀, H.T. Pagden, Pres. by P.J.M Greenslade, B.M. 1966-477, Salini det. ( BMNH) . Guadalcanal Province: Guadalcanal: 11 km NW of Honiara, Bonegi beach, 9°22.8′S 159°52.2′E, 0 m a.s.l., 12.xii.2013, 1♂, 3♀, J. Hájek lgt., P. Kment det. ( NMPC) ; ca. 3.5 km SE of Barana vill., 9°29.8′S, 159°59.5′E, 190 m a.s.l., clearing in secondary forest, at light, 24.xi.–14.xii.2013, 4♂, 2♀, J. Horák lgt., P. Kment det. (2♂, 1♀ NMPC; 1♂ MMBC; 1♂, 1♀ NIM); same locality, 24.xi.–14.xii.2013, 1♂, 2♀, J. Hájek lgt., P. Kment det. ( NMPC) ; Guadalcanar [sic]. Aola , 5.x.1928, 2♂, 1♀, E. Paravicini lgt., P. Kment det. ( NHMB) ; Guadalcanar [sic], Aloa [sic], ix.1928, 1♀, no collector, P. Kment det. ( NHMB) ; Honiara , at light, 17.ix.1965, 1♀, Roy. Soc. Exped., Salini det., B.M. 1966-1 ( BMNH) ; Honiara (gardens), 19.xi.–13.xii.2013, 2♂, 2♀, J. Hájek lgt., P. Kment det. ( NMPC) ; Honiara District, Kukum , 20.vii.1954, 4♂, 2♀, E.S. Brown lgt., Salini det., Brit. Mus, 1957-201 ( BMNH) ; Kukum , at light, xii.1965, 1♀, Ezikel lgt., Salini det., B.M. 1966-1 ( BMNH) ; Luvnga , 18.viii.1954, 1♂, no collector, Salini det. ( BMNH) ; Popomanasiu, Nuhu , low vegetation around village, 23.x.1965, 1♀, Roy. Soc. Exped., Salini det., B.M. 1966-1 ( BMNH) ; Rere , 23.v.1922, 1♀, E.A. Armytage lgt., B.M. 1947-284, Salini det. ( BMNH) ; Rere , 1928, 1♀, R.W. Paine lgt., Pres. by Imp. Inst. Ent. Brit. Mus. 1931-588, Salini det. ( BMNH) ; Rere , feeding on coconut spathe, 19.viii.1928, 1♀, R.W. Paine lgt., Uvarov 1929 det. as Axiagastus cambelli, Salini revid. ( BMNH) ; Rere , 19.viii.1928, feeding on coconut spathe, 4♂, R.W. Paine lgt., Pres. by Imp. Inst. Ent. Brit. Mus. 1931-588, Salini det. ( BMNH) ; Ruavalu , 20.xi.1954, 1♂, E.S. Brown lgt., Salini det. ( BMNH) ; West Guadalcanal, Ciri env., 400–600 m a.s.l., xi.–xii.2018, 2♂, 2♀, St. Jakl lgt., P. Kment det. ( BMNH) ; Ru Avatu [= Ruavatu], x.1928, 2♂, no collector, P. Kment det. ( NHMB) ;. Isabel Province: Santa Isabel: Nagolau , 29.iv.1963, 1♀, M. Mcquillan lgt., Pres. by P.J.M. Greenslade lgt., B.M. 1966-477, Salini det. ( BMNH) ; Tatamba , 3.i.1963, 1♀, 24.ii.1963, 1♀, M. Mcquillan lgt., Pres. by P.J.M. Greenslade, B.M. 1966-477, Salini det. ( BMNH) . Makira-Ulawa Province: Makira: San Cristobal , 14.x.1955, 4♀, E.S. Brown, by P.J.M. Greenslade lgt., B.M. 1966-477, Salini det. ( BMNH) ; San Cristoval, camp 2, Tilley lamp, during heavy rain, 25.vii.1965, 1♂, Roy. Soc. Exped., B.M. 1966-1, Salini det. ( BMNH) ; San Cristoval, Wainoni Mission , black light, coconut plantation, 20.– 21.vii.1965, 1♂, Roy. Soc. Exped., B.M. 1966-1, Salini det. ( BMNH) ; San Cristoval, Wainoni Mission , black light, coconut plantation, 20.–21.vii.1965, 3♂ 3♀, Roy. Soc. Exped., B.M. 1966-1, G.M. Black 1969 det., Salini revid. ( BMNH) ; R.J.A.W. Lever, 26.ii.1934, 1♀, Pres. by P.J.M. Greenslade lgt., B. M. 1966-477, Salini det. ( BMNH) . Malaita Province: Malaita: Auki , 4.x.1964, 1♂, P. Greenslade lgt., Pres. by P.J.M. Greenslade lgt., B.M. 1966-477, Salini det. ( BMNH) ; Auki harbour, at wharf lights, 24.xi.1965, 2♂, 1♀, Roy. Soc. Exped., B.M. 1966-1, Salini det. ( BMNH) ; Baunani , 10.ix.1954, 1♂, no collector, Salini det. ( BMNH) . Rennell and Bellona Province: Bellona: Angailio , 20.xi.1955, 1♂ 5♀ 1 spec. (abdomen missing), E.S. Brown lgt., Brit. Mus. 1956-419, Salini det. ( BMNH) ; Henagotu , 28.v.1965, 1♂, no collector, Salini det. ( BMNH) ; Ngotokaanava , 30.x.1963, 1♀, P.J.M. Greenslade lgt., B.M. 1966-20, Salini det. ( BMNH) . Rennell: Hutinpal , 28.xi.1955, 1♂, E.S. Brown lgt., Salini det. ( BMNH) ; Hutuna , 17.x.1953, 1♀, 13.xi.1953, 3♀, 2.xi.1953, 3♀, 20.xi.1953, 1♀, J.D. Bradley lgt., Rennel I. expedition, B.M. 1954-222, Salini det. ( BMNH) ; Lavanggu , 23.xi.1955, 2♂, 4♀, E.S. Brown lgt., Brit. Mus. 1956-419, Salini det. ( BMNH) ; Marange , 30.xi.1955, 1♀, E.S. Brown lgt., Brit. Mus. 1956-419, Salini det. ( BMNH) ; Niupani , 22.xi.1953, 1♀, J.D. Bradley lgt., Salini det. ( BMNH) ; Tigoa , 9.–11.xi.1953, 2♀, J.D. Bradley lgt., Salini det. ( BMNH) ; Rennell I., July–Aug. 1909, 1♂, W.W. Froggatt lgt., Salini det. ( BMNH) ; Rennell Is. , 4.xi.1964, 1♀, P.J.M. Greenslade lgt., B.M. 1966-20, Salini det. ( BMNH) ; Rennell Is., 4.x.1964, 1♂, Pres. by P.J.M. Greenslade lgt., B.M. 1966-477, P. Greenslade lgt., Salini det. ( BMNH) . Temotu Province: Santa Cruz: Nimetuo viii GR 980226, iii.–viii.1983, 3♂ 1♀, M.J. Gaywood lgt., B. M. 1984-112, Salini det. ( BMNH) . Western Province: Gizo: Gizo , 25.viii.1955, 3♀, 1♂, E.S. Brown lgt., Salini det. ( BMNH) ; Gizo , 21.viii.1963, 1♂, 1♀, M. Mcquillan lgt., Pres. by P.J.M Greenslade, B.M. 1966-477, Salini det. ( BMNH) . Kolombangara: Kulambangra , 14.vi.1922, 2♂, 9♀, E.A. Armytage lgt., B.M. 1947-284, Salini det. ( BMNH) ; Kulombongara Is., Karikana Estate , 2.x.1933, 1♀, H.T. Pagden, presented by Com. Inst. Ent. B.M. 1948-536, Salini det. ( BMNH) ; Karikana Estate , 2.x.1933, 1♂, H.T. Pagden, presented by Com. Inst. Ent. B.M. 1948-536, Salini det. ( BMNH) ; Salomonen, Vila , 1932, 3♀, C. Malcher lgt., P. Kment det. ( NHMB) . New Georgia: Munda , sweeping coastal vegetation near mission, 29.viii.1965, 2♀, Roy. Soc. Exped., B.M, 1966- 1, Salini det. ( BMNH) . Rendova: Mgeli , 17.x.1954, 1♀, E.S. Brown lgt., Salini det. ( BMNH) ; Ugali , 17.x.1954, 1♂, E.S. Brown lgt., Salini det. ( BMNH) . VANUATU: Espiritu Santo, Luganville , IHRO, coconut inflorescence, 30.xi.1983, 1♂, M.J.W. Cock lgt., 83-424, C.I.E Coll., A15654 , M.S.K. Ghauri 1984 det., as Axiagastus cambelli, Pres. by Comm. Inst. Ent., B.M. 1984-1, Salini det. ( BMNH) ; New Hebrides: Malekula , i.1930, 1♂, L.E. Cheesman lgt., Salini det. ( BMNH) ; Santo Isl. , New Hebrides, I.A.H.O., iv.1974, 2♂, 1♀, P. Cochereau lgt., P. Kment det. ( MNHN) . FIJI: Vanua Levu Isl., Salt lake Env., 16°47′55.15″S 179°31′1.29 ″ E, 7.–8.viii.2014, 1♂, A. Zubov lgt., ex Roca-Cusachs Personal Collection, M. Roca-Cusachs det. 2021 ( NIM) .

Redescription. Colour, integument and vestiture ( Figs 45–51). Body above black with the following well-expressed yellowish to orange-yellow markings:longitudinal stripes on disc of head, anterior margin of pronotum, one sublateral transverse stripe on anterior margin of pronotum, 1+1 obliquely straight stripes sublateral to anterolateral margins of pronotum, few irregular transverselly arranged patches on anterior disc of pronotum (sometimes absent), thick or sometimes thin, transverse stripe along basal margin of scutellum; thin or moderately thick, irregular lateral patch at middle of lateral margins of scutellum, moderately broad, crescent-shaped spot on scutellar apex; anterolateral margins of coria and lateral margins of abdomen, and a few small, scattered spots on coria. Antennae ochraceous or smoky brown, devoid of punctures; membrane smoky brown; antero- and posterolateral angles of connexival segments black; punctures black, distributed uniformly over entire dorsum, including head; lateral yellowish spots on connexival segments devoid of punctures, remaining areas of connexival segments with fine, concolourous punctures. Ventral surface, pale yellow with black transverse stripes as follows: head with one longitudinal stripe on either side of bucculae, diverging from posterior end of bucculae towards compound eye, one broken stripe above base of each antenna, alternate transverse stripes on thoracic pleura, thick transverse stripe on intersegmental sutures of ventrites joining another thick longitudinal stripe on middle of abdominal ventrites and to thick longitudinal stripe submedial to abdominal ventrites; thick submedial stripe to abdominal ventrites laterally joining to black transverse muscle scars; apices of buccular denticles, a moderately large spot coalescing with spiracle anteriorly, apex of labium, apex of each ostiolar peritreme, and tarsal claws, anterior and posterolateral angles of abdominal ventrites III–VII, black; black punctures concentrated along longitudinal, black stripe on either side of bucculae and remaining region of ventral surface of head impunctate; thorax and abdomen on ventral surface with brown, coarse punctures, more concentrated towards lateral region. Legs concolourous with ventral body colour, with coarse, round punctures, densely distributed on femora and tibiae.

Structure. Labium surpassing posterior margin of ventrite IV. Other characters as in generic redescription.

Male genitalia ( Figs 52, 54–70, 79–82). Genital capsule ( Figs 54–57, 61–64, 79‒82) subquadrate, dorsal rim more deeply incised than ventral rim; lateral wall of dorsal rim concave, more or less smooth, sclerotized black, ending in a well-developed denticle contiguous with deep, transverse emargination (te) at middle of dorsal rim; dorsal sinus of posterior aperture broadly U-shaped (ds), ventral margin of posterior aperture semiovate; ventral rim including posterolateral angles bordered with a row of moderately elongate, dark brown setae; ventral rim broadly, shallowly concave (vr) at middle; posterolateral lobes rounded in lateral view ( Figs 57, 64, 82); infoldings of ventral rim deeply impressed on either side of moderately developed distension at middle, distension sunken, emarginate short U-shaped at middle, visible on dorsal view of genital capsule; infoldings of ventral rim laterally (inner to posterolateral lobes) with a prominent, apically rounded or blunt, sclerotized, black denticle (dt). Paramere simple, crown finger-like (flp), apex slightly deflected towards dorsal margin of genital capsule ( Figs 59, 66), dorsal margin (dm) uniformly convex in lateral view, numerous fine, short hairs on lateral margins of finger-like crown, elongate setae along periphery of laminate disc (ld); crown abruptly narrowed towards apex, ending in acuminate apex in lateral view; stem (st) elongate, apodeme (am) disc-like. Phallus ( Figs 68–70). Articulatory apparatus as in Figs 68‒70; phallotheca less sclerotized, distal part transparent with ventral convex projection in close proximity with inner margin of processes of aedeagus; two pairs of dorsal conjunctival processes ( Fig. 70: dp1 and dp2); lower one (dp2) sclerotized, ribbon-like, apically rounded, upper one (dp1) much shorter than dp2, completely membranous; aedeagus short, deflected dorsad, apex swollen, drop-like, transparent, with embedded phallotreme, processes of aedeagus elongate, as shown in Figs 68‒70.

Female genitalia ( Figs 53, 71‒73). Terminalia ( Figs 71, 72). Valvifers VIII almost as in A. rosmarus with inner posterolateral angles obtusangulate, posterior margins convex; valvifers IX, laterotergites IX, and laterotergites VIII as in A. rosmarus . Gynatrium. Orifice of spermathecal duct surrounded by narrow, inverted, U-shaped sclerite; ring sclerites indistinct. Spermatheca ( Fig. 73). Spermathecal dilation as in A. rosmarus , proximal spermathecal duct tubular, distal spermathecal duct (dsd) gradually widened towards proximal flange, wider than intermediate part of spermatheca; apical receptacle orbicular with three ductules, with longest one surpassing proximal flange, apically not twisted, hook-like.

Differential diagnosis. This species is usually shining black with well-expressed bright yellowish or ochraceous spots and pale antennae as explained above in the colouration section. This species is distinct in having a slightly deflected apex of the parameral crown ( Figs 59, 66), a uniformly convex dorsal margin (dm) of the parameral crown in lateral view, and also in the shape of the processes of the aedeagus (pa).

Etymology. The species name Axiagastus cambelli was presumably dedicated to William Howard Campbell (1859–1910), an Irish Presbyterian missionary who worked with the London Missionary Society in southern India, a naturalist and collector of the type series ( Anonymus 2024d). Although the collector’s surname was Campbell, it was spelled without a “p” in the original description, as was the species name derived from it. Therefore, it is unclear whether this was a typographical error or not; it is possible that Distant himself believed this to be the correct spelling, as it also appears on the locality data label. Consequently, the name of this species, cambelli , is not an incorrect original spelling that needs to be corrected ( ICZN 1999: Arts: 32.5.1 and 32.3). The specific epithet marmoratus (- a, - um) is a Latin adjective meaning “marbled”, referring to the colouration pattern of the species.

Biology and plant association. This species, also known as the coconut spathe bug or coconut flower bug, is often found in abundance on the newly opened spadices of Cocos nucifera ( Arecaceae ), feeding on both male and female flowers (e.g., Phillips 1940, Lever 1969). It was regarded as an important pest of the coconuts in some parts of its distribution area, causing immature nutfall (e.g., Tothill 1929, Simmonds 1925, Dwyer 1937). However, Phillips (1940) provided evidence that the serious immature nutfall was instead caused by Amblypelta cocophaga China, 1934 ( Heteroptera : Coreidae ). It can cause some fall of immature nuts, but its economic status is difficult to assess, since the damage done by it appears to be much less than the number of insects present would suggest. The nutfall is probably due to the loss of sap rather than to the injection of toxic saliva, as found in the Coreidae ( Phillips 1940, Lever 1969). However, O’Sullivan (1973) observed that under sustained, heavy attack by A. cambelli the young inflorescences showed premature necrosis, most of the nuts failed to develop and eventually dropped. Feeding also occurred on older inflorescences, but usually with lesser intensity. Nuts over four months appeared to be little affected by A. cambelli feeding ( O’Sullivan 1973). Cochereau (1965) and Stapley (1973) also confirmed that the species was harmful only in very high abundances. Axiagastus cambelli was also recorded from Areca ( Arecaceae ) in the Solomon Islands ( Lever 1933a, b, 1969; Cochereau 1964), but intensive search in the Bismarck Archipelago has not revealed any A. cambelli on Areca spp. , nor would it feed on it under laboratory conditions ( O’Sullivan 1973). In the laboratory, adult A. cambelli fed on fruits of the cluster palm Ptychosperma sp. ( Baloch 1973). Finally, Lever (1933b) reported egg masses of A. cambelli being found also on the leaves of Casuarina sp. ( Casuarinaceae ) in the Solomon Islands, but he considered that the eggs were a chance occurrence (cf. O’Sullivan 1973). The mention of “cocoa nuts” on the labels of type specimens is clearly a mistake for coconuts (see Distant 1911a).

Various aspects of the biology of A. cambelli have been studied (e.g., Tothill 1929, Lever 1933b, Baloch 1973 and O’Sullivan 1973), including mating, oviposition, egg hatching, larval development, the longevity of adult bugs, and feeding and damage caused to the injured plants. Considerable attention was paid to parasitoids as potential control agents of this species. Eggs are parasitised by Trissolcus painei ( Ferrière, 1933) ( Ferrière 1933; Lever 1934b; Nixon 1938, 1943; Cochereau 1964, all as Microphanurus painei ; Baloch 1973, O’Sullivan 1973, Johnson 1991) and Trissolcus basalis (Wollaston, 1858) ( Johns 1941, Lever 1941, Cochereau 1964, as Microphanurus basalis ) ( Hymenoptera : Scelionidae ), Anastatus axiagasti Ferrière, 1933 ( Ferrière 1933; Lever 1934a, b; Phillips 1956; Cochereau 1964), Anastatus ? dasyni Ferrière, 1935 and Anastatus sp. ( Baloch 1973, O’Sullivan 1973) ( Hymenoptera : Eupelmidae ), Ooencyrtus papilionis Ashmead, 1905 ( Phillips 1941, as Ooencyrtus malayensis Ferrière, 1931 ) ( Hymenoptera : Encyrtidae ), and Acroclisoides megacephalus Girault & Dodd, 1915 ( Baloch 1973, O’Sullivan 1973, Sabbatini Peverieri et al. 2019) ( Hymenoptera : Pteromalidae ). The adults of Aridelus niger ( Papp, 1974) ( Hymenoptera : Braconidae : Euphorinae) were reared from larvae of this species ( Baloch 1973, O’Sullivan 1973, both as Aridelus sp. ; Papp 1974, as Arideloides niger ). Two species of tachinid flies Pentatomophaga bicincta Meijere, 1917 (introduced from Australia), Trichopoda pennipes (Fabricius, 1781) (introduced from Florida) and an unidentified species ( Diptera : Tachinidae ) were observed to oviposit on A. cambelli ( Phillips 1956 and O’Connor 1950, respectively). According to Phillips (1956), larvae of P. bicincta failed to develop in it ( Phillips 1956). Later, Baloch (1973) reported successful development of P. bicincta in A. cambelli . O’Sullivan (1973) succeeded to breed T. pennipes from both adults and larvae collected in Bougainville and another tachinid (gen. et sp. indet.) from A. cambelli on New Ireland.An unidentified strepsipteran was found on adult A. cambelli in the Bismarck Archipelago by O’Sullivan (1973).

The ants Oecophylla smaragdina (Fabricius, 1775) ( Hymenoptera : Formicidae ) ( Tothill 1929, Lever 1933c, Baloch 1973, O’Sullivan 1973, Stapley 1980; Mariau 1998, as O. longinoda ) are very active predators of the larvae and adults of A. cambelli , and due to this the coconut spathe bug only rarely occurs on the palms inhabited by the weaver ants.

Distribution. Australia: Queensland (this paper); Papua New Guinea ( Lever 1969, Papua New Guinea and Bismarck Archipelago, no exact records): East New Britain Province: Duke of York Island ( Distant 1911a), New Britain: Napapar ( Papp 1974), Gazelle Peninsula ( Baloch 1973, O’Sullivan 1973, Arnold 2011); West New Britain Province: Lolobau Island ( O’Sullivan 1973); Milne Bay Province: Misima Island ( Distant 1911a, as Aignan I.), Woodlark Island ( Montrouzier 1855, Stål 1864); New Ireland Province: Feni Islands ( O’Sullivan 1973, as Anir Island), Lihir group: Lihir Island ( Baloch 1973, O’Sullivan 1973) and Masahet Island ( O’Sullivan 1973), New Hanover Island ( Dwyer 1937, O’Sullivan 1973), New Ireland ( O’Sullivan 1973), Tanga Islands ( O’Sullivan 1973, as Tangar Island); Autonomous Region of Bougainville: Bougainville ( O’Sullivan 1973), Buka Island ( O’Sullivan 1973); Fiji (new record), Samoa (new record); Solomon Islands ( Distant 1911a, b; Froggatt 1912; Ferrière 1933; Lever 1934b; Phillips 1940; Arnold 2011), Vanuatu ( Cochereau 1964, 1965; Tercinier et al. 1964; Gross 1975).

The species appears to be common on the islands east of the New Guinea mainland, Solomon Islands and Vanuatu (see references above). However, we have not encountered any collection specimens or exact published records from the Indonesian part of New Guinea, the Papua New Guinea mainland, or New Caledonia. Despite past searches for this species, it has not previously been found in Fiji (e.g., Simmonds 1925). During the current study, we examined a single specimen each from Queensland (exact location not specified), Fiji, and West Samoa; however, the presence of the species in these remote areas requires further confirmation. We cannot exclude the possibility of A. cambelli becoming an invasive species in some regions outside of its native distribution area.

Remarks. Montrouzier (1855) provided only a brief description of his Pentatoma Marmoratum [translated from the French]: “Length 7 lig. [= 15.79 mm]. Dark yellow, dotted with black. A dark band at the posterior edge of the pronotum. Two brown spots on the sides of the scutellum, and a third of the same colour preceding the apex, which is a beautiful yellow. Elytra brown, mottled with yellow. Underside of the abdomen and legs dark yellow, finely dotted with black. Antennae brown. There are individuals in whom the spots on the scutellum are coalescent, and the general colour of the body is darkened. Found in Woodlark.” As the original description indicates the variability in colouration, it is evident that the species was described based on an unspecified number of specimens (syntypic). However, prior to the current study, no syntypes have been recognized. Therefore, we searched the whereabouts of Montrouzier’s collection, yielding the following results.

Reverendus Pater Jean Xavier Hyacinthe Montrouzier (1820–1897) was a Marist priest and a Sorbonne-trained naturalist, born in Montpellier ( France), who spent most of his life as a missionary in Oceania and died there. Prior to Secondy (2012) ’s detailed biography (see below), what little was known of Montrouzier was the information that could be gathered from administrative documents, the prefaces to his major works (The fauna of Woodlark Island and The fauna of New Caledonia), brief obituaries ( Grouvelle 1897, Trimen 1898), and studies or volumes mentioning him ( O’Reilly 1931; Laracy 1976, 2010; Gouillard 2004). Laracy (1976, 2010) had used some letters of the Marist fathers, including some by Father Montrouzier, to document their mission in Melanesia, as Duffy would do later ( Duffy 2013 –2015), but their purpose was not to dive into Xavier Montrouzier’s life, as was the focus of Secondy’s (2012) publication. Through 453 letters written to members of his family and of his congregation by Xavier Montrouzier over a 50 year period (1845–1895), Secondy (2012) unveiled details of Montrouzier’s life in Oceania, as well as his inner thoughts. The book tells, among many other things, of the risks taken by the missionaries in those uncharted territories (Bishop Epalle’s murder, Montrouzier’s injury which took months to heal, the loss of his conchological collection in a revolt in 1862, etc.), of Montrouzier’s needs for supplies (insect boxes and pins, sheets for his herbarium, some alcohol to preserve his fishes, molluscs and reptiles, etc.), of his desire to publish his work quickly (not out of vanity but for it to be a credit to his religious congregation and to the French scientific community), and of the fate of his collections sent to Paris, Bordeaux, Lyon, and Montpellier, including those which were lost on the way (either the ship sank or they were thrown overboard, as Montrouzier seemed to believe), but very little was written about his entomological collections.

We thus turned to the works of our German colleagues ( Horn & Kahle 1935 –1937, Horn et al. 1990, Groll 2017) which explained that some of Montrouzier’s collection was lost, some of it was destroyed by Anthrenus , and some of it was auctioned by Deyrolle (although that part may have included only Coleoptera ), while his Hemiptera specimens reached Henri Schouteden (1881–1972) via the son of the coleopterist Benoît-Philibert Perroud (1796–1878). The main collection of H. Schouteden is now deposited in the Musée Royal de l’Afrique Centrale, Tervuren, Belgium (MRAC), but this includes only his African material (Stéphane Hanot, pers. comm.). The small non-African part of Schouteden’s collection is now deposited in the Institut Royal des Sciences Naturelles de Belgique, Belgium (ISNB), as confirmed by Jérome Constant who works on the taxonomy and phylogeny of the Hemiptera there. Schouteden (1907) listed 36 of Montrouzier’s species, including types, as being in his hands, but Axiagastus marmoratus was not included. However, other depositories are mentioned (such as the Staatliches Museum für Tierkund in Dresden, Germany (SMTD) and the Hungarian Natural History Museum in Budapest, Hungary (HNHM)).

In his entry on Montrouzier, Rider (2022) mentions most of the above but he also adds an important piece of information: “Occasionally, Stål indicated examining type specimens for various Montrouzier species, and indicated that the specimens were deposited in the Naturhistoriska Riksmuseet, Sweden (NHRS) or the Signoret collection which is now in the Naturhistorisches Museum Wien, Austria (NHMW)”. Indeed, Carl Stål (1833–1878) made use, in various works ( Stål 1864, 1866, 1870, for instance), of such expressions as “Sec. ex. typ.” or, in full, “Secundum exemplum typicum” (“According to -the/a- type specimen”) or simply “exemplum typicum” and often acknowledged Victor Signoret (1816–1889) for sending type specimens (of Montrouzier’s species, or of those of Guérin-Méneville, Amyot & Serville…). This certainly agrees with the quotations by Strickland (1845) reported in Webb et al. (2013), that expressed the need to fix a type for a group to which other specimens could be compared. As Latin does not use definite articles, it is arguable whether the specimens Stål referred to as “exemplum typicum” have been designated as lectotypes or not (according to ICZN 1999: Arts 74.5 and 74.6), their mention nevertheless gives us a clue as to their whereabouts, either NHMW or NHRS (depending on whether these were returned to Signoret or not and, in the latter case, Signoret might have donated them to Stål).

Stål (1864) transferred Pentatoma marmoratum to Axiagastus , yet according to Gustafsson (2006), there is no type or even material of this species in NHRS. In this 1864 paper, Stål makes no mention of knowing the whereabouts of the/an “exemplum typicum” of this species (as he does for Ploeogaster mammosus ) or that one was sent to him by Signoret (as he does for Passaleutes geniculatus). He mentions, however, the presence of some material of P. marmoratum in Signoret’s collection (now mostly in NHMW). One of us (Petr Kment) found and imaged a historical specimen in NHMW. The specimen bears three labels (two by Signoret) and an original determination label in Montrouzier’s handwriting. The latter could be verified thanks to a page of one of Montrouzier’s letter, given as a sample of his handwriting by Secondy (2012), the label of Pentatoma Reyana (currently Anaxarchus reyi, Pentatominae ) provided by Horn & Kahle (1937), a label of the type of Tingis australis ( Fig. 78), given by Schouteden to Drake ( Drake 1954) and currently in the National Museum of Natural History, Washington D.C., USA (USNM) ( Drake & Ruhoff 1965; Tom Henry, pers. comm.), as well as through direct comparison with the determination label of Hyparete boitardii (Pentatominae) , currently on loan from ISNB to NMPC (P. Kment, pers. observ.).

After the end of his mission on Woodlark Island, from August 1851 to January 1853, Montrouzier stayed in Sydney ( Australia) where a “Mr MacLeay” let him use his vast library and 77,000 specimen-rich collection and encouraged him to publish his Fauna of Woodlark Island ( Secondy 2012). “Mr MacLeay” can only refer to William Sharp Macleay (1792–1865) as, in 1851–1853, he was the only member of his family settled there. Upon his death, his cousin, William John Macleay (1820–1891), inherited his entomological collection, enriched it, turned into a natural history collection and donated it to the nation in 1888 ( Holland 1988; Holland & Stanbury 1988). The Macleay collection is now part of the Chau Chak Wing Museum, University of Sydney ( Anonymus 2025). In 1962, Elizabeth Hahn finalized a preliminary list of the insect types in the collection ( Hahn 1962, Hahn 1988). “In 1969 an agreement was reached which enabled recognized type-specimens of insects lodged in the Macleay Museum, University of Sydney, to be transferred to the Australian National Insect Collection (A.N.I.C.), Canberra, on a ‘permanent loan’ basis” ( Stevens & Carver 1986). Overall, more than 9000 Australian and exotic insect types had been identified ( Horning 1988). Ensued several publications listing the types that had been discovered and were now preserved at the ANIC; all stressed the possibility of there being still unrecognized types ( Whitley & Stanbury 1976, Britton & Stanbury 1981, Stevens & Carver 1986, Naumann et al. 1994). While the Hemiptera type specimens transferred to the ANIC were all of Australian provenance ( Stevens & Carver 1986), among the Coleoptera type specimens was listed a syntype of Onthobium macleayi Montrouzier, 1860 ( Scarabeidae ), from New Caledonia, although Montrouzier was not mentioned in the list of authors ( Britton & Stanbury 1981). Hence the Chau Chak Wing Museum could yet be housing unrecognized types, including some of Montrouzier’s species, especially if Montrouzier had dedicated them to Macleay.

Despite the fact that Montrouzier had been able to benefit from the Macleay collection while in Sydney, both A. Doué (in the preface to Montrouzier 1860) and E.D. [= Eugène Desmarest?] (in a note to Montrouzier 1861) expressed how, away from all scientific centres, from the literature and means of comparison, it was difficult for Montrouzier to identify species and to give them correct generic placements. Therefore, the greatest expert of their groups was enlisted to examine Montrouzier’s specimens and to revise his descriptions. Signoret kindly accepted these tasks for the Hemiptera part of Montrouzier’s work and, probably, obtained some types as a reward.

Owing to the aforementioned facts, accepting that Stål might not have been aware that what could only have been material recently acquired by Signoret was part of Montrouzier’s type series and according to ICZN (1999: Art. 72.4.1.1), the aforementioned historical specimen located in NHMW is recognized as a syntype and, in order to fix the identity of the species, is hereby designated as its lectotype ICZN 1999: Art. 74).

Axiagastus cambelli was described by Distant (1911) from an unspecified number of specimens (syntypic) with the following data: “ Solomon Islands (W.H. Cambell); Duke of York Island; Aignan Island (Brit. Mus.). On Solomon Islands “destructive to coconuts” (W.H. Cambell).”.

One male from the original type series of Axiagastus cambelli (see Type material examined above) is here designated as lectotype ( Figs 67–70) to fix the identity of the species in the present sense (viz ICZN 1999: Article 74.7). This specimen is clearly conspecific with the lectotype of A. marmoratus in NHMW and the two species are therefore considered synonyms. The arguments for retaining the junior species name, as the valid name for the species, are as follows:

Pentatoma marmoratum has been known for a long time only from its original description by Montrouzier (1855) and the subsequent paper by Stål (1864) transferring the species to the genus Axiagastus . Later it has been cited only in lists and catalogues referring to the preceding two papers (see Walker 1867, Stål 1876, Lethierry & Severin 1893, Kirkaldy 1909). In the last hundred years, the species was mentioned in a regular paper only once by Arnold (2011), who provided photograph of its habitus along with records of two females, one from Papua New Guinea (New Britain: Gazelle Peninsula) and one from the Solomon Islands (Rennell Island). On the other hand, Axiagastus cambelli (partly under its incorrect subsequent spelling A. campbelli ) has been recognized as a pest of coconuts, since Froggatt (1912), and has been the subject of numerous papers on its life cycle, the damage caused to the coconuts, as well as the associated fauna of parasitoids and predators as the possible means of its biological control. We have collected a sample of 55 papers published by 39 different first authors, and distributed more or less regularly within the period delimited by Distant (1911a,b) and Exélis et al. (2023) (for complete list see catalogue part above). The Article 23.9.1 of the ICZN (1999), dealing with the reversal of precedence, says: “prevailing usage must be maintained when the following conditions are both met: 23.9.1.1. the senior synonym or homonym has not been used as a valid name after 1899, and 23.9.1.2. the junior synonym or homonym has been used for a particular taxon, as its presumed valid name, in at least 25 works, published by at least 10 authors in the immediately preceding 50 years and encompassing a span of not less than 10 years.” While the condition 23.9.1.2 is met for the name Axiagastus cambelli , the condition 23.9.1.1. does not apply due to the use of A. marmoratus as valid species in the paper by Arnold (2011). However, as the name A. cambelli is in the prevailing usage and it is the only name of the taxon occurring in the papers dealing with it as a pest, we propose to continue using A. cambelli as the valid name (viz ICZN 1999: Article 82.1). The Case will be submitted to the Commission for a ruling under the plenary power to fix the prevailing usage of A. cambelli Distant and conditionally suppress Pentatoma marmoratum Montrouzier (viz ICZN 1999: Article 81.2.3).