Some Hawaiian Ecological Notes1

By IRA LA RIVERS Unive,·sity ot Califomict, Be,·"keley

The following obsel'vations were p 1·omptcd by the trap failures which the author encountered while collecti11g 011 Oahu, 'l'enitory of Hawaii, during 194,1 and 1945. The area eoncerned, a small point or peninsula jutting into the northeast corner of P earl Harbor, proved increasingly intc1·csting and prcliminat·y ecologic surveys showed it to b e well-fitted for the stndy of relationships "·ithin a restL·ictcd region. Aqua tic, am­ phibious, and terrestrial , while n ot specifically abundant, were indi,·idually quite common in some groups, aud the popula­ tion was sufficient to proYide a cross-section of theit· ecologies. The limited extent of the area involved was more or 1<-ss com­ pensated for by the rxistence of a \·ariety of habitats anti a ni­ mals characteristic of each. The choice of the area \n.ts accidental but nevertheless as fortunate as p o sible in view or lhe well­ known limitation o.f the H awaiian l slands' natural rannnc as well as the extensive addition of fo t:cign species, which fa<•lors together bring disappointment to the travelling coll ector· of most biological groups. As implied, mo t of the animals involved in this stud.v were immigrants. The author was not awa re of any indigenou!\ ·peeic · other than eerta in birds, fishes, and crustaceans. There was some 1·easonable doubt that the three sp ecies of r eptiles involved were indigenous in the sen se that their· occupancy of t he Ilawaiian I slands preceded lhaL of man who has been a resident of t he region for some ccnturie . It cannot be known how the lizards arTivcd, but in contrast to modern artificial dispersion, their accidental carr·iage in the canoes of the Islands' aborigines could be cousidel'ed more like natural transportation on floating debris. As is usual in most terrestrial habitats, insects were the com­ mon er;!. animal~ considering the nnmhcrs of both species and

1 This study was aided by a rescorch grant from the Oahu )Jicroscopical Society, 1944·45. G 'l'UE \V AS)IA l'\ :>; ( 'nLLI·:CTIIR [Vol. 7. ~o. 3 indiddu als. Bit·ds. crust a~eans . fis he>-, t't'ptilt•s. amphibia ns, and a solitary mammal fol lo"·ed in ordct· or abnnda rH·t'. 'l'etT<'strial animals fonnf.'d the g-reat bulk of thr spec irs: aquat i<' animals were a small minorit~' , and the amphibious group (t><:ologically) included onlr thl'cc spN:ies, a f rog, n toall, and a Rhm·e crah. Because of the li m it ed extent of thr arrn undl'l' C'cding h abits of snch or t li o mHjor species t hat could he obser ved in detail.

T he relativPl ~ - small num ber of anirmd~ in,·oh·ed in the study are listed below:

AVES Ricllmo11cle11a r ardillalis. Cardinal STIJRXIO.\E (Starlings) Paroorio c ucullala. B•·azil ian :1 C1'idollle1·e.~ Iris tis. l\Iynah cardinal

C()l.l-,tmn.\E \RHEIOAF. (Herons and Bitterns) (Pigeons and Doves) :-.·yclirora:r 11yctir'ora:r lloactli. Black-cr·owned Night heron FI /1'€'/Jiopelirt rlliueu .~i .,, Chinese lu rlle-do,·e

l'I.OC'P.IIl.\E (StlRITOWS) GeoJJ eliu st1·iola trrmq1Lilla, Peace· rut dove i'(ls.vrl· cl<>uP<>.~tit'IIN. Tl ouse spanow H('OI.(li',\ V W .\ 1·: (Saudpipers and fo'HI N(I II . I. IIli\t-: (l•'in(• hes) SnipeR) Cm·porl aru.v wrtrira1111S fnm talis. * lfel t•rostrl us i nr·11 uus. Wa nde•·­ Linnet ing ta ttler (winter v l sil;~nt) ' lndiRenous species or nnlllral \'isitants. August, 19-!8] LA Rl\'ERS-HAWAIJA.K E coLOGICAL NoTES 7

n .\LLIDAE (Ralls and Coots) CClJIDNJD.\ E (Moray Eels) •GallimLla chlo7·o1ms sandvichen· • Lycodon tis sp., Moray eel sis. Hawaiian gallinule CRUSTACEA llt.:Cl' R\' IIIOSTICIO,\E (Stilts and Avocets) J'ORTl' NID.\F; (Swimming Crabs )

• Tfimant0[>11 .~ llimantopus k11ttd· :Scylla scn·ata, "Samoan" crab .~cni, H awaiian s tilt • P oclo71htll ahn1ts vigil, Hawaiian crab MAMMALIA ,.N erJ tu1111.~ .~anuttinolcntns, Holly \'IV~: I tltiiiA I' (Civets and Mon­ crab gooses) un.\PRIIJ''" (Shore Ct·abs) lferprst es m1L1100. Common mon· goose • M et07JOU1'UI>Su s messo1·, S hore crab t' F.J.IIl.\1:; (Cats) Felis clomcst icus. House cat XA~Tn IU.\t; •Epixa1Jtlltts sp., 1\fud crab REPTI LIA ocYroom.\E (Sand Crabs) GEC J' O~ IUAF. (Qeckos) • ocypodc ccrot o7>llt11alma. Ghost •Hcmida c tylu.~ gornotii. Fox gecko crab • L C7Jidodactvlus Zugub1·is, Mourn· lng geck o P.\ L_\EliO~IOAE (Shrimps) *Palaenwn cl e/Jilis, Common SC I NCID~E (Sklnks) s hrimp • Emoia cyanunr, Azure-tailed sklnk LI GYOlD.\E (Fleelbugs) .. Li{JYCla sp., F.leetbug AMPHIBIA o:-.

llUYO~ J OAE (Toads) INSECTA JJufo nwrinus. Tropical American load Cou;OPTErt.\ CURCULIONIO.\E PISCES Rhabdocnemis obsc~t1·a, Sugarcane borer ta.t:OTJIIO.\ t.: (Sleepers) Oxydcma tusi/onnc • Elcol7·is tusca . Oopu Akupa • Tt:l\EBRIONJOAE ••ot;cJLliiAf' (Top Minnows) A 1n111 opl10ra i11s1tla ri.~ Gambusia a1Ji 11is, Mosquito fish GonOCC]JitalttS SC I'ialttm J1J oil'ienisia l atipinna, Molly Blapst

~ II ' J I LWA I~ (Mullets ) • llJ·:Rl [ EWI'J llAE •.H ujil CCJJhahts, Common mullet D cnncstes mannorcttus 88 THE W .\ S:\IAKX CoLLECTOR [Vol. 7, No.3

JJJSTt:RIU.\t; Lt:PJUOPTJ::R.\

Sctprimts lugen .~ 11 .\X.\ 111,\1:; Pal'Olltalus la utus Uarwi.~ tJICJ'iJifJUs. l\lonarch but· tertly SUMt.\IUEII>AF. A 1J itodius liviclis ,I taelf'i, u.~ CO OliO I us Picris 1'CLJW e, Cabbage butterfly

IIOS TRIC IIJO.\t; S l' llf ll'(lJU,\t:

A m/)11 i OC 1'11,8 COI"IIILillS Jl ersc d1t(f'ltlala XylotllritJs 1·eligiosa

Cl·: lt,UI UH' III.\1•: OnTIItJl''l't·: nA

Cy/lene cTi?t icorni.~ J.O Cl ' ST!IIM: Sybra altentmls OJ:ya ch'ilrell .~ i s

II \'llROl'llll.lU.\1:: Tt.'1'TIOOI\UDAE Dal'fylosternton abflominalis Elfmaea tJU11 Ctifem, Lesser katy­ did UOCCJ:S EJ,LJDAE i lt,·actam onJiw ambig1w Olla abdomi11alis Conocephalus saltator Omimts coentleus Platyomus lividigastet· l l .\XTID.U: Ooelo71hora it~aequalis 1'e11oclem augusti1Jemtis i l Z y(l lttlei]JCS IIL.\TTID.\E ~:L.\ 'I ' ERIDAE l 'e1'i1JI,anelc~ ame1·icnna. American M clcmoxcwthns melct!tocep halus cocJ(ronch OllctlcolofJeclius e1·ytl11'0loma Blattella y er111o11ica, Crotonbug Pyt" II Oscelilts .~ttr!1!amensis :S ITIOL'1,1DAE IJiJJIOf)lera clytiscoicles 0C£1'/>0Jlhil1ts h1onemlis N lttJelln s ll}Jerllecl il'ilon Oal'JIOflhillts ltemipterrts Cut ilia .vo1·or· Carpopllihts di11t i diai11S Haptoncus orula1·is Dt:Rli APTt:R.\ !;T.\PIIYLTli'ID.\t: Cll t: I.ISOCII 111.\ E Oreot>hilu.y ma xillo .~ tt s Oll elisocll e.v mo1·io. Black earwig

1.. \BID I)RlliAf: 1.1 OF: I,Lt: LilJA!:: IAibic/111'0 1' ltla1·ia Trapezostigma lccrcrata. Common Mas ter Pcmtala /lat;esccns. Globe skimmer

.\ESl lNTDAE HEDUV IIIIi\ 1·:

A 11/tX jttnitts. Common zilia /:elus 1'e11ardi Angn;;t, 1!)-! ] LA Rt\'ERs-llA.IY.\11.\ X EcoLOGICAL ~o·ms 9

DII.>TF.JI.\ X\"J.OCOI'ID.\E SYICI'll Jll.\ E Xyloc-opa l'CI1' i/IIOI(·/a. Valley car· Tubi/em an:onnn. Drone fly penter bee Volucella obeHa, Cactus fly .\PIUAt: AiJIS mellifera. Honey hee HY ~~ ~: xoPT~: n .\

N nania a Jl1H!11il 'i{lrt.~ l er. Cockroach wu sp

'l'lw most perlim•nt obscn·alions arc tabulat<'d ;;pr<:iflcnlly.

TIERPES'L'ES )1 U XGO 'rhe mongoose is omni ,·orons, eating- food in all stages oE pt·e;;ernttion a nd decay. The hitter fact 1\'l.IS or some Slli'Jl l'ise to me, since the animal, in general habits all(} appearan<'c, is a finely-constructed predatory machine well eapable or living on a diet of its contemporary fauna. The principal concern here iS' the setting down of a fe1r illustrs' beha1·ior in obtaining foods of. often, qnite different categories. l n tcrcst in a cnrsory field examination of the mon•7 oose 's fvod habit was aroused after encountering it m; a nuisance fac~0r while trapping for insects with " high" meat bait. Baits o£ putrid meats were so consistently taken b.r the mongoose, and the species was so cunning in its effol'ls that all attempts to obtain in eels by ncb methods had to be abandoned. The first inslanc·e of the failure of one of the traps was noted when several decaying Scylla serrata of mP

TABLE II Analysis of lizard stomachs

li emidactylus Lt pidoductylus Emoia Gun~o t ii ( 2 7 )a Lugubris (38)h Cyanuru (9)c A HTIIIWI'Uil>i EA'I'I•::-> by 1''' Il''' III* !V* I" I I" III* IV' I * II* Ill* rv• Ammophora insularis...... 61 111 13j 2.2 131 271 2.8 1 1 2 0.19 Conocephalus seriatum ...... f> j 101 101 1.9 9 1 1014 i 191 1.9 0 Blapstinus dila tatus ...... 81 141 2.8 8 1 13 17j 2.6 3 3 6 0.59 Aphodius lividis ...... 2 j 2 j 1~1 0.39 31 0 . 5~ 1 1 2 0.1 9 Alaenius cognatus ...... lj 2 1 21 0.39 ~ I 0.79 0 Sybra altern!J-US...... 0 1 I I !I 2 0.1S 0 Dermestes ma n uor atus ...... 21 5 1 41 0.99 2 0.39 0 !I 21 Sap1·inus lugens ...... 1 1 11 21 0.19 11 il 2 0.19 1 3 0.59 Paromalus lautus ...... 11 0.19 I 0 11 Mela noxanthus melanocephal us .. 0 1 1j 2 0.19 0 Amphice1·us COI'IIUt US ...... 31 :t0.59 !I 8 0.79 0 Xylothrips religiosa...... ~I 6 1.2 1 1 2 0.19 Rha.bdocriem is obscura...... ~I 11 131 2.2 ~ I 151 19 2.9 2 3 4 0.59 Oxydema fusifonne ...... 9 1 12 191 2.4 9 1 141 19 2.8 1 2 2 0.39 Creophilus maxillosus · · ······· ········· 21 8 41 l.G 6 1 0.'19 0 Azya lute ipes ...... 2 j 5 0.99 ~ I 2 0.39 1 1 2 0.19 Platyomus lividigaste r ...... 11 1 ~I 0.19 !I' 1 1 2 0.1 9 1 1 2 0.19 Olla abdominalis ...... 2 4 0.39 0 Coelopbo1·a inaequalis...... ~I 2 0.39 il 1 2 0.1£ 0 I Curinus coeruleus ...... ·········· 11 2 ~ I 0.39 41 5 0.9S 0 1 I Haptoncus ocularis ...... 01 2 0.39 01 2 1 ~I I Carpophilus humeralis ...... 5 j 11 101 2.2 15 311 3.8 3 4 61 0.79 Ca1·pophilus hemipterus...... 41 0.79 61 1911 1 13 2.2 0 I Dactylosternum abdominalis ...... 11 il 0.19 Ol 0 I Oxya chinensis...... 21 61 !I1. 2 6 8 1 13 1.6 0 I At racta morpha a mbigua ...... 3 1 3 6 0.59 7 121 15 2.4 0 I Conocephalus saltator...... 3 1 5 6 0.99 6 61 131 1.2 0 I Pycnoscelius surinamensis ...... 111 17 23 3.4 12 23 3.6 3 6 1.2 181 Blattella germanica ...... ····- 151 16 31 3.2 19 21 401 4.2 4 9 ~I 1.9 Diploptera dytiscoides ...... ---·· 91 13 19 2.6 13 17 271 3.4 5 101 0.99 Periplaneta ame l'icana ...... 9 16 19 3.2 10 2.9 2 0.59 21 1 41 Cutilia, soro r ...... ········· 1 1 21 0.19 3 1 ~, 6 0.59 0 ~I Supella supellectilium ...... 0 I 0 I 1 0.19 La bidura riparia ...... 3 3 6 0.59 2 21 4 1 0.3f 0 11 21 Chelisoches morio. ... ····················· 4 5 8 0.99 0 I I 0 Zelus renardi ...... 2 2 4 0.3!! 2 3 1 4 1 0.59 0 I Tub'Hera a rvorum ...... ·········· 1 1 2 0.19 0 I I 0 Apis mellife ra ...... 11 0.19 0 Miridae, sp...... ········ O.H Porcellio sp ...... 1 7 2.2 ~ I L!J ~ I 2 4 o.3n ·- ~ I ul ~ I Jl TOTALS (502) ...... 12051 I 1251 1 I I 461 I a stomachs were empty or contain ed unrccogni1.able material. h15 s tomachs were empty or contained unrecognizable material. c:2 stomachs were empty or contained unrecognizable material. 1* / N umber of stomachs containing the species. II* / Total number of specimens. IIl*/Per cent of all lizard stomachs in which ' \\'Crc found (48). IV"~~ / Per 'cent of total specimens found in all stomacl1s. 92 THE W.\SYA:-\ ~ COJ.I.F.CTOR [Vol. 7, No.3

.A week later, an excess of waste oil tloating into the shallow tidepools along the shore of P earl Harbor killed :evcral Scyllc£ SCITata, and after sufficient water rotting, these were lt·ieu again as bait. This time, everal jars of various si%es \\'Cl'e !-U lll\ in the ground to rim-Je,·el a nd closed \\'ith appl·opriatcly-sit~l'U tin fun­ nels with apertui·cs only la1~'ge enough to admit small to medium­ sized insects. 'l'hc foll owing day ull traps WCI'O round LhO I'Ollghly despoiled. Small er jars had bt•cll llu ~ up and some J· oll ed com­ pletely hom their beds; funnels had been compl etely rcmovc

Jn nddition to its llUisancc artivitic•s, ll <'l'peslrs 111W11go was ocrasiona ll y I'Ol llltl in t he role or <1 din'rt c·ompc1i1 0l', Durin g August, 19-b '] LA Rn·Ens-HAWATI.\N EcoLOOICAL KO'l'F. 93 erah coll ecting in Pearl TTarbor and the ponds borclel'ing it, sev­ e•·al crah-hnnl ing mongooses we•·e seen adroitly fh;]Jing for crabs in shallow water along the shore. \Vhile sitting- motionlrss on H rHi~ed •·ailrond embankment laid arross a swampy area at the edge of the harhor, I noticed two of these animals roopcrating in c·ntehing smnll specimens of the abundant g•·apsid .lf rfo1WrJ1'aznnts messor. ;\ ser ies of small, porous and ligh t volcanir ston es lay in a t.hin sh<'<'1 oF wat er beside the r mba nkment , the wate1· no­ where clNl(W L' th 11 11 1m inch, and roveri 11 p; some ninr square yards. A ll stonrs wrt·c Pasi l ~, turned over a nd, if nnrnolrst eel for any length of time, were ePr tain t o he host to one Ol' mor e crabs. Xfte1· I he customary period of precautionary delay-" getting the look of things"-the hYo mongooses set about turning- over stonNt Xot a sing-It' crab, once flnshecl. manag(.'(l to rscap<.'. one partner ponnc·ing upon them as the othrr flipped stones ovrr. As each crab was raught. it was carried to a ch· ~· spot and eatrn, both animals sharing in the food. Apparently they lmrw there was plenty fot· both. The total ratch was small, ho\\·cve1·, only fiw crabs; T had clone e:s:actl;> the same thing- t\YO l1ont·s before and taken <.'i~hl specimens. From the abundanct• or both the c1·abs and the mong-ooses. this tahlean must be a common ocrur­ renee, for rcrta inl:v t11e two T watched were experic>nrrcl M it.

Tn ::1

Tn on<.' othrr in. tancl' a large old male mon~oose succes.«fnll;\­ ranaht a mrdinm-sizrd hlue or Hawaiian c•·ab, Podophthfllm1tS t:i(Jil . !!S the latlt'J' strayed into sl1allow \rater at the edge of the pond nN1rly hori- 7.ontal instrnd of more normal 45• angle, since it was in water just row r in~ the c·arapare. A la1·gc ~L'C<.'ll darn<'l', 1h<> rommon zilia ( A.1w.r .i•win.~). with h~r attrmpts to oviposit on water lily 1-' lalks, l11Hl brPn my crntcr of attrartiQn. ThP mongoose appeared sn

t1uring the Jl l'l't<'d ing fe,,- minllt(;!s. T hud nolirrd the crab ns a possible ~p<•<· inwn myself. .As the mongoose pa usrd nt I he water, the crab sidled q11idd~· neare1·, rlnll·ning- pond deh1·is l'i~ot·o u sl~­ with his c· hch~t•, t•ntiJ·eJ~- una"·arc of th<' JH'e~r,we or an enemy. At that moment wlwn the crah rame nen1· l ~ · to the <'dg-e of the water, ancl ~<'<'nwd ha lf in alld lullf ont, the mongoo~e rlarted in quickly, J'oJ·l'l't•et in an inch of watt•r, hincll'<•et pl nnlt'tl finnly on the mutl dy lmuk, and swept t he luckless Ct'ltb high and ch·~ ­ int·o laltg" lt•d l' t~ ge tnt ion on t'lw biltdc With an cqna ll .v qui c- k

lllOI'Cll1 Cilt, ht' I lll'll e(l, l)OUI1CC'(l 0 11 his Jll'l',\'1 illld l'lll'l'ied it off into th<' hr ush. l'odophlhalm?ts riail wns not a slug-g-ish c·rab, hut this Oil<' had no c·hanre. It w11s not probRble. howcl'et·, that the mongoosl' !WI many oppo1·tnnitics to rat('h this pnrticular species, exrcpt hy such J'at·c chance l'ncounters as the ahovc.

NeitlH' l' or the other two ('()Jllll)()n swimming dcrnpods, the large "Samoau" r rab (8cylla scrrala). and the white OJ' h o JI~ ­ crab (Ncpltt1111S smtguinolenfus) , sN'mC'cl to han• been victimized by- the mongoose, since neithel' was C\ '('1' uote

One of th<' most interesting- predations or the mong-oose ron­ c·c l'lled the numcrou~ ghost cmhs (Ocypodc ce/'lllopl!l7wlmn) which freq11rnll'd sand~- heachrs in all situations about the i.land. 'l'hcse elusi,·c ct·abs \\'<'l'e most <'Ommo nly seen dm ·in~ low tides, s<·amperin!{ about 1 h<' wet sands feeding- on YegC'tablc matter left hy tile recedi ng- \\'Dte t•s_ The e:vt•s we1·c bo1'11e on shot·t stalks, a!Jowing maxi mum Yisibility. lt "·as ~<'ldom possible to Nlptnre a u older s pPc imrn mn1y from its hmTow. bnt ~· ou n A'et · indi­ viduals. pc!'lwp" lwcause the~- lucked a permanent homP. t'an abont th<' saucls in ~!l·eat numhi' J'S dnring low tides. Th<'~- wPt'C l'Xtem;iq> l~· dug- 1'1'0111 their bnrt·ows and used for food by the local populut ion, and such despoil('(] hunow. were common. It 1\'i:ls not until l spndNI a l1all-grown mongoosP ft·om a J'C<·cntl:v <' nla l'gNI llllllH'I, ll'hile ro ll ed i n~ the (' l'llbs myselC, th11 t other agpnciC's than hunt an hcin gs brrn mt· snspc<' L Fl'agment s of IH'wly-clcll tlNl Otypodf' ;:h(']ls nnd dnws nccompHnircl the small .Uugust, Hl4 ] LA RI\'ERs-H AWAHA:-: EcoLOGICAL ).;oTES 95 mongoose. . 'nch bits of crab skeleton, some ft·csh enough to haYc been n sourct• of food for some animal a few hotll·s 1n·evious, hnd been tnrncd np seYeral times during my own search for hott It'll hie mat<'l'illl, hut without any realization of t hrit· possible significance. No mongoo ·es wet·e a<'lnally seen dig-gin~ into bur­ rows, but their tt·acks, plns fresh g-host rrab fragments in de­ s poiled I unncls, pi us an occasion al mongoose dug ont of such bunows, pl 11s the preclator 's kno wn pt·cdilcct ion for ct·fl h meat whm·evc1· obtainable, f nl'llish ecl ttca rl y in cl is puLahl c d t·c nmstan­ tinl nnd inct·i minating cvit.lcncc, especiall y when surh evidence w11s found on a lone, l ittle-fre()uen ted hcach whic·h bore no :igns of' t't>ccnt human occupancy.

In addition to rrabs. mongooses \'('1·~- often obtaitwcl fi-..h by much the !'iamc methods. F ish we1·c newt· sren takrn from watrr in which the~· had [reedom to swim, but were caught only when sit·andcd in small mud- and ticlc-pool!'i. I n the most stt·iking instance, three mongooses were di!irovcred ratrhin!! and eating se>cral half-grown mullet (iJlujil ccpltalus) stranclecl i•1 a tid£>­ \\·ater pool at the edge of P earl H arbor. PJ·ec·edi•Jg- t hi~. mvl ~evc J ·a l times a fter\\'ards, freshly-scattered honl's ancl rh£>wed fishhcads were mute testimony t o simila r acti,·ity of th i!; pt·cdator . l\'Iuch more rommon in bordering pools and estuarirs than the ntllllct, t wo ::-pcc i c~ of top mimw ws (Gumb usin alf'nis nml Jll ol­ lif'nisia lctti7Jinnn ) and a sleeper (.A Icot ris f llSNt) were often !rapped in some numbers when the tide went out. Ucrpc.~tes mrmgo <:leaned up mo t of the>'e. lca,·ing fl'w sc1·aps fo1· s<:an•ng-<'r­ ing" JLc t opogra psu s and E pi:canth 11s. On one o<'<·asion, a fa<;\ icl ions mongoose was seen meticulous! ~- cleaning its teeth after a meal of several Eleotris. sitting on its hanneh<'s and picking its teeth rather daintily with its foreclawl'r-lln impr<'sl

Althongh r·eptiles as a group were SNH'ce in t he jslands, most of the species J'cpt·cscnted were common enough. The most pop­ ulow; was the small mourning gt>cko. Lcpidod.ortyllt.~ 1rt{Jttln·is, fonncl cverywherr hnt par ticnlarly about old bni lclings, tr r<'s, a 11 d pih•s of dohl'is. Ct·epuscular hotll'S constituted the periocl oE most ndivit ,v, 11l which t.imc th <' li ;.-: a ,. cl~ o t'l cn swa r·mecl over· t he sides o l' <1 bnnclonNl huildings. 01w of t heit· p l'inci pHI RO UI'ecs of 96 THE IVA s~rA NN CoLLECTOR [Vol. 7, No.3 food was the very abundant German roach or Crotonbug, Blat­ tella gennanica, which flew freely at this time of: day. In stalking these geckos about old buildings, where they were most easily taken, it was soon apparent tl1at the mongoose was more elementally interested than I was, and several instances of capture were seen. On one particular occasion, the mongoose's efforts were confined to the lower two-feet of the wall, since it could not r each or jump successfully above that limH. In 1he failing light, ·1he first intimation of the presence of a mongoo~e was a light brown streak which dashed from the corner opposite me and pounced upon something about six inches f rom 1he ground. Almost immediately the crunching of bones became audible. Some fifteen minntes previously, nearly a dozen of the lizards had been bottled from the same wall, and they were now Leg·inning to come out again. Other specimens in the immediate vicinity of the victim could be heard scurrying away over the dry boards, but in four minutes the mongoose made another cap­ ture. In the subsequent opening of mongoose stomachs, lizard remains were usually found, indicating they comprised an im­ portant part of the predator's diet. Two other common Uzards, the fox gecko ( H ernidactylus gar­ notii) and tl1e blue-tailed skink (Emoin cyan·unt) were also iden­ tified from stomach contents. As evidence, however, of the vicissitudes of life. can be cited the case of the distinctive old male gecko who lived for over three months in the same pile of lumber in which a ft>male mongoose reared a set of young, without coming to harm. Dur­ ing an initial visit to the spot, bordering the only wooded plot in the area, an attempt to collect the lizard resulted in the animal losing its tail, but not its liberty. .After that it was distinctive and r eadily recognized, but no longer worth collecting. At the end of three months, when conditions were such that he could no longer be kept under observation, this individual was still occupying the pile of lumber and still managed to elude the mongoose; undoubtedly the latter had good hunting in the im­ mediate vicinity, but there was little doubt she wonld have added him to the menu had an opportunity presented itself. Othe;r sources of mongoose food wet·e the n nmcrous bullfrogs (Rctna ca.tesbciarw) and tropical toads (Btifo 11W1·inus) living in Angu.t, 1!).! ] L A RI\' ERS- JlAWAll.\1\ E coLOGICAL, :\on :s fl7 a sc•ries of bJ·a<' kish lily ponds, ad jac,•nt, but without any direc·t eonne<'t ions, lo the P earl Harbor fring-e of t idepools. 'l'lw pond fauna was small to the point of barrenness. <·ontaining onl~· the mcntionNl amphibians, Gambusia. an unidentified fn•sh-water snail, and some minutae, principall:v c·iliatl'S, eopt> po<>Scs. :'\o i11 stances ot <:apt n1·c Wl'rc notNl, but remains o.f both speci<•!i Wl't·e round in mcH J::,Wo!ie stomachs, and on one occa­ sion, the f l'l'Shly-killed remains of a bullfJ·og- we1·e fo und on a bank beside one or tht• pool .

Local birds, of l>e,·cml spec i e~, we1·e I i ke w ise a sou,·c·c of mon­ g-Oo!ic food. Comm onest residents wei'C the m~· n a h ( .l cridotheres tristis), honse sparrow ( Passer dow csticw;). peaceful uO\·e ( Ocopelia striata trm zquil1a), Chinese turtlcdo,·c ( l rcptopclia c lt in c n .~ is), linnet (Cnrpodacus m e.ricmws fron talis}, black­ (·J·owJ•ed n ight heron ( .Y ycticora.r nycticora.r ll onclli), and wan­ dering tattler (lleteroscelns i?z conlls). The cardinal ( Nichmon­ clena ca1·dinalis) and Knudsen stilt ( fli m ri ~cd while tug­ gi n~ at the ca rcass of a night heron one br·ighL aft ernoon on a small, thi ckl y-,·cgetated peninsula near tlw Point. Inspec-tion .·howed the bi 1·d to have been dead at least a co uplc of dnys, and the mongoose Willi patently p ursui ng that p o J i c~· Of' CXpcdi CllC')' whieh n('(·cpts any rood at hand . .As in the c·ase of the amphi­ bialls, no s pecific instances of binJ-cupture were noted, but bird remains in lliOllgOO<;C s to m ach ~ J1l'O\' icl<'<1 J•eJiahJe !'\'itlt•n<·e O[ the ~ro up as n sout·ce of food. The eo mmonest iuentifia ble remains belonged to the ti n ~' do,·e Gco prlia. an ahundant, quiC' t, and rathc1· tm1w ~ pe< ·it> s n s ua ll ~· ronnel ft• Pdin ~ in !imall c• lt>:lJ·inp;s well StliTOUntlcd b~' pt·ofnse ,-egetntion whirh ]H'O\'itlecl adcqnatc (' 0\'<' L' fc)J· h nn l·. ing· mongooses. A f t· l~!i hl y - ki lled mynn h \\'li S f'onnd lm­ d\'r cit·<· mnslanC'es ruling ou t t he only other ptedator in the 98 THF. WASMANN CoLT, ECTOR [Vol. 7, No.3 vicinity, the domestic cat ( F cl1:s domesticus). 'l'be lJody was found on a narrow, semi-muddy spit of marsh ground bet,recn two small streams where the ground was very impressionable and showed only mongoose footprints. 'l' he bird had been killed but a few minutes before, and my advent undoubtedly frightened away the predator.

Most bird remains found in stomach boli were indeterminable as to species, but there were smaller bones of uudonbted passerin<' origin, indicating eithel' of the common species Passer clomesticus or Carpodac1ts mexicanns frontalis, ot both, as occasional prey. Some of the specifically unidentifiable material belonged to small rats which wer e undoubtedly caught in adjacent canefields, and served as a very important source of food.

Fe'w insect r.emains were found in mongoo;;e stomachs, but determinable species included the large bla ttiJ Periplaneta ame·riwna, and the medilm1-sized species Pycnoscelius sn1·ina­ mensis and Diploptem dytiscoicles. Occasional indetermi.nable fragments of other Orthoptera were found amid two recog·nizable species, T enoclem augustipennis and Elimaea punctifem. An isopod, .D£gyda sp., very common, was also identified from exam­ ined boli.

'l'he only direct competitors of nmn.qo were eight distinctively­ colored domestic cats, pets on the Base. 'l'hey did considerable successful hunting i11 the small canepatch and through the grown-over areas populated by rats, birds, and lizards. The only dead mongoose seen dnring the time the area. was under observa­ tion was a half-grown individual taken by one of these cats. The captor, a large black-and-white tom, met me one day as I was going down to the waterside, dropped the mongoose rather indifferently on the ground, pjcli:ed it up as indifferently after I passed, and carried it to its box. It refused to eat the kill, however, and the mongoose was burned in the ineiueeator. It was not probable that a full-grown mongoose would have need to fear even a large eat, for the superior agility ot the former would be ample compensation for Hs smallel' size. The strong musk glands would he a factor in the c<:~ts' g·enel'al a voidance o E H e·1·pestes, and was probably t l1e reason tl1e small victim above was 1·efusecl as food, for its oL1or was quite IH'onom1ccL1. August, 194 ] LA Rl\·~::ns~fuwAIL\:" EcoLOGICAl. :\O'l'F:S 99

:\Iy own lmpping fm· indiYiduals of the sp(.'(:it•s was done with . imple dt•adfalls, which they entered without fl'ar or caution if suitable baits were used; in this manner, mau~· mo1·e c·oulcl ha,·e h<'Pil c·aught in addition to 23 w!Jo!:e stomuchs were annlp~ed .

. \CHIDO'l'Lilo:H IO:S 'I' HIS'I'IS

'l'he m,,·nnll , one ol' ti H~ commonest birds. li r ld 1ll11c·h tlw silnll' posit io n in thP nvian community as does I hr S tnlt•s idc' stnJ·Iing ; ll lJc.lli kc lhc stnrli ng, it was an inquisitivr. aggo 1·c•ssivc•, ontni vo r·ous ;lttillllll. rt s (•Oil tl'iiSting- plumage made it (Ill' III OSt (•l)llspit·II OllS hin l in the fil• ld, with exc·eption of tlw h1·illin11 1. hut mul'h t'ill't'L', Rich111011dr1111 flll'cliualis : when unst>l'll . its g-ut·t·ulousue:--s was sut·c to attrac·t ;tttcntion. Lntclligent and wat·~· , it \\'11!-i impossible to tntp b~· ct·ude m<'thods at m~· disposctl, l'H\in• l~· rel'u>.iug dc'ad­ l'nlls with nn~ · bait. e,·en those constnwted of screen. Twenty­ ninr -;pcc·imens ohtai1wd o\·er a thl'ee-mouth pt' t·iod W('I'C all takrn with an a it• aun; ITerp cstes lllll1lgo. tl<>sl l'o,,·ing- or fording all t y p e~ o[ t1·a ps Ia id fo r whatenor spt•cies of unima I. and ellting :-:ur h bai ts ns wc t·e :et out, was perhaps the bi g-g-t•sl si ug-lc fa<:tor wh y it wa~ impossible to tr ap an:\'thing h ut mong·ooses. Omni\'orousncss or the mynah was attested b.r tho l'll<'t that insects, seeds, bread rt·mnbs, an pl·rc·t•tl i ng species, were the bulk of its animal food : e.g., Pe ri plaHclu americmw, D iploplcl'fl clyliscoides, l'ycnostrl i1ts surinflllll'11sis. mttl Blultcllu germ(mica. 'l' hc less-rommou or nate rna<:h, Supdlu supcllr r - 1i lium. was iul•nt ifietl in one instance from :-;tomac·h t·ot:tl'HL. J,igydct sp. was pre. en t in a nmnher of r·a-;es. On one oec·asion, a m_\n ah was seen flyi ng- off with a small li7A~n l caught on a boardwalk thrown ac·t·o~s a small marsh. 'I'hr only li~at•d ft'l'Cj\lenting tlus J)il l'ticllhtl' ~pot was tJH' ('()Jnll1011 /,czn'dodaclyiHs lii{Jitbri.~, basking gt·egal·iously nl a ll times of t he tlny. An occnsional small lizard hotH' \\'liS [ound in 111 .\'ltah stomu r hs, llll(l one ~: l ml l r eferable to tltc sk ink Emoiu r·yrmnra. Appm·ently A cridOIIIIJI'(!S reel \\'ith l '(' i, (·OmJnon rcu1i peuc ScolnJJ M'lclro wbsJ,ill i JJ f's. l'ot· l'ru g'lll Cn ts of' th e laitm· Wt' l'<' par t of the boli examin ed. 100 1'nE \VAsi\IANN CoLLECTOR [Vol. 7, 1\o. 3

'l'he stinger of a small, slender, rare and undetermil1ed species of scorpion was 1·ecovercd from one stomaeh. Numerons seeds and vegetable matter forming the bulk of the boli were not identified. A solitary instance of fish-eatill g was chanced upon late one afternoon when a mynah was noted feeding- on a small, wriggling Eleotris fi/Sca. stranded by the tide. The outgoing water had tran1:>formed a shallow tidevool to a muclfiat which at various times during a three-month period Rimilarly trapped four common fish: E leotris f u:;ca, ilfnjil ce]Jhalus, Gambnsia ajfinis, and Mollienisia laiipinna and left them l'or whatcve1· predator chanced along. Scavengering propensities of the mynah we1·c brought out by the quarreling of two vociferous individuals over an abandoned fishhead 01~ the beach, while another bird was discovered peck­ ing assiduously at an unpalatable (I thought) mass of stranded jellyfish ncar the sa me spot seYeral days later.

NYC'l'lCOHA..'C NYC'l'ICOI{AX HOACTLI 'l'he black-cl'owncd night heron was a welcome sight among an ar ray of birds largely composed of foreign species, since it was a familiar sig·ht on the mainland. It enjoyed the distinction of being the largest bird of: the area tmdcr observation, and was C!tlite common for there was an abundance of marshy tracts suited to its needs. Few instances of f eeding were noted, but since the species possessed the same habit-char acteristics as elsewhere, its diet certainly consisted of elements associated with it in the States. The stomach contents of two specimens cor­ roborated this, co ntaining larg·ely fi sh remains and one small Rana catesbeiann. 'l'he common mullet (Jllujil cephal1ts), living in large schools in Peal'l Harbor, anu invauing estuaries and connected fringing pools in numbers, was t he only recognizable item among the fish remains. 'l'he thied stomach held a solitary aambnsia. ajfini;; and a quantity of crustacean fragments r ep­ resenting Jlfetopoyrap.ms mcssor, Neptnnns .~a ngninolenhts, and T'ulaemon deuilis.

UEllllDACTYJ.US GARNO'l'll The fox gecko ·was the largest Islm1d lizard, and in number, second only to Le7Jidodactyl1t.s luunbris in the co mmonalty. Here, August, l!J!8] LA RI\'ERS-HAWAIIAX EcoLOGJCAr" ~ O'I'ES 101

it was associated with the secreti ,.e skink Emoia cym1 11ra in the more densely vegetated portions o( the tract, while J,. luyubris predominated over open areas. Although t he two geckos were of a nocturnal "Toup. hunting­ cxtensh·ely during twilight hours, hoth wcrc fond of sunning them!->elvc. at all hom·s of the day on suitable hoards, .fences, building walls, open places, and similar situation . The old male II. ywmoti?: with whic!t I became more or Jes!'> acquainted (see lle1·pestcs mungo), eustomarily utili~ed a pile or old railroad t i<'s for home and basking site, and could be found there reg-n­ lady at most a ny ti me of day dur·ing the three months he was obser·vrd. H e stalked flies about tl1e woodpile, and caug- ht ants, t·oaehes. and isopoch; whenever andlablc. Observable twilight activities seemed largely directed against the ,·e r·y common blat­ tid Blattclla genmmica, flying in great numbers between d usk and darknes ·. Tts principal crepuscular adaptation, el liptical pupil., was no apparent detcn ent to efficient daylight hunting. Prey was swallowed in characteristic reptilian fashion, ]ar~e in­ sects I aborionsl~· , often r equiring several minntes. I nc,·cr saw the anima] discard a t·oach because of size, although some ncady adult Pcriplrmcta americana seemed wider than its head. The oddest capture was the killing of a half-grown fox ~ccko by a six-inch gian t centipede, Scolopendra snbspinipcs, 11 capt nrc which I faci litated. Abundance and contiguity of both spt't'ies militated against its being a rare occurrence. In this instance l dro,·c the li7.ard nncler a rock trying to effect a capture ; moving tbe rock. lizard and centipede 'wre found . trugg-ling together, and the tOI'mer was struck se>eral time. by t he rhilopod 's fang-s. At I his point, the centipede released its grip 11nd dar-ted awny, hut the gecko was already part i a U~· paral~· zcd; turning on its back, death came in a few minutes, accompanit>d by convulsions which became spasmodic l\Yitching, then ceased. 'l' wo months pl·e­ ,·iously, J had bt'en "bitten" by a four-inch spcrimen of S. s u bspinipe.~ with symptoms no more scyere t.han those of a Bom­ blts stin~. to which I am less susceptible than the average per­ son. Cons ider·ing- the natnre of its prey, it is natmal that the c•en t i prdc possesf'cs mol'c toxici t~· for c·olcl-bloodcd anima Is. I Tc midactyltiS was pt·ovender fo t· hn·ger· prcda tot·s sur.h as TT er})fl sf os 1JIII?I(JO, Ji' clis dorne sliws, 11 11d Acridolfuwes t?·islis; and thc>se were individnally abnnntble 102 TuE \V.\S~I.\ 1\ x 'ut.J.ECTUR l Yol. 7, i'\o. 3

toll. . 'olitnl',\' fox ge<'kos ,,-erP oc·casionall~· l'ouud insiut> occupied building!; pt·cying Ul)OII the thri,·ing t·oac:h popnlat ion inYariably prc.scnl.

t.t-:PIDODAC'I' YLL'S t.! 'Gl'IIHI~ '!'he mmtt'll i ng- g-ecko was til(' c•ommonc•st Isla ml I iza t·d , but sli g- htl,v !-itnalkr tiHtn the· l'ox g-t·<·ko. l'nlike tlw othct· two laccr­ t ilt•s, iL \\'liS c· h il a pl'imc d iet. August, 1948] LA Rt\'BRS-HAWAIIAN E coLOG I CAL Xo·.rEs 103

E:UOIA CYANUHA

'l'he blue-tailed skink was an associate of the fox gecko in this area and while uot uneommon, was .·eldom seen berausc of its ~crrc ti,·e habits. 'L'he mallest of the three species, its enemies were uudonbtedly much the same as those or the geekos, and stomach contents showed its diet lo be id('ntienl.

ItANA CA~' .I ~SD I~ l ANA T he hnllfrog, native to eastem (Tnit cd StaiCll, has been success­ tull y int roduccd to the Islands and is now well-established. In !h is arNt, it Ji,·ed in a seric· of intel'l ocking lil~· ponds whose brackish waters were partially upland dt·ainag-c, partially harbor seepage. From ld bceu arri ved at-but the fact remains that the spec·ies lived, and li ved well. Circumstances were unfavorabl e for successfnl trapping, a nt' contained a disinll'grating- Lcpidodoclylus. the serond a small member of its own species, and the third fragment· of a Ia rg-c Periplaneta. .-\.. first thought would he that the spec·ies bct·c is hunting afield, toad-[nshion, bccanse of the sterile ponds, but no C\' id<'nce of this wa round. Enemies were (•onfined to a few species, but the abundance of cc r t11i n of these made them formidable. The mongoose was the most important, and !'eYet·al stomachs <'Ontained bullfrog remains. Thrc•C' heron stomachs were examined, and one held a small RanfT. The nhundanre of the black-crowned night heron and t he .fact lhnt its diet wa!-i more restricted tha n that or the mongoose, placrcl it ns one of t.h c l'm·cmost encm i<>s of the ft·og. On e flne a<.lult hull l'rog wa!-i brought in and eat en by a large t omrat. 104 TuF. \VAsMANN CoJ_, LEC'l'OR lVol. 7, No.3

IN SEC'!' A More than fifty species of insects were coll ected in the area, and the total present was probably nearer a hundred. Not one of those collected was positively known to be indigenous, and there is reasonable doubt that any native speeies still existed in the low­ lands in this vicinity. The eollec1·or of Hawaiian insects now :6nds the uplands and especially the original foreBted areas on the two mountain ranges, ·waianae and Koolau, the best sources of native material. The three commonest beetles, Gonocephal1ts se1·iatnm, .tlmmo­ p7101'Cl insula-ris, and Blapslinus dilatatus, were the sole represen­ tatives of the world-wide Tenebrionidae; small and ,nondescript, after the fashion of so mllny o.£ the family, they were character­ istic of open, dusty situations and were often found traveling about such clearings in large numbers, especially the latter spe­ cies. They were common provender for all insectivores, and seemed to be of little economic importance. Several families common to decaying animal matter \\·ere rep­ resented by one or two species: Sap1·imts lt~gens and 11aromalns lautus (Histeridae) ; Aphodius lividis and Ataenius cognat11s (Scarabaeidae) ; Dennestes sp. (Dermestidae) ; Dactyloster/l'lt.m abdominalis (ITydrophilidae); and Creophiltts max£llosns (Sta­ phylinidae) and could be found wherever such food was present. On occasion, they. were a staple in the diet of lizards and birds. Organic material did not remain intact long in the warm, bumicl atmosphere of the Islands, but was of fairly common occurrenc(' about outlying buildings and fllrms where numbers of animals were kept. The largest economic gt'OUp of beetles wa s the Coccinellidae, Ollu abdominal1·s, Azya lnteipes, Coeloph ora inaequal£s, Ou1·imts coendeus, and Platyomns livicligaster, all imported to control in .. sect pests, all well-established and abundant. The fruit beetles Ca·rpophilus lwmemlis, C. hemipterus, C. dimid,iattt.s, and Jlaptonc7.t S owlaris (Nitidulidae) flew b? thou­ sands when the str ong, pungent odo1· of ripe and decaying pin<~ ­ apple was on the fields. Ripe pineapples picked where they fell on the railroad right-of-way and carried t o the middle of a cane­ field or swampy tract invariably were covered by one or all four .August, 194 ] LA Rtn:ns--HAWAIL\X EcoLOGICAL .:\oTES 105

:-, pedes the next day. They '"l"erc a limited ~onn· c of food in tlw area, for thci 1· l->ma ll size and unc-el'lain otclllT<'I1<'l' made them

CRUSTACEA 'l' his group was l'epresented hr a few prominent . peC'ie» tli,·ided into ~e ve n families, on ( ~- two or which wet'(' tet'l'CStl'i al. .-\11 \\'Cl'C ab11n dHnt and terr<'slrial species were an important sou1·ce of rood fot· other animals. 'rln:ee of the five reptantian:s were portunids : Scylln .sormta, 1\'epttmns sml,l}ninole?lhts, and Podophi7wlwu.~ t·igil. Sl'ylla, the so-ca ll ed "Samoan" crab, strong, massiYe, s w ee tl~' - flavor cd , greatly exceeded the others in size. It was supposed tlwt the first inJi,·iuuals were introduced from Samoa. li enee the local name; its ineptnes · was r eadily apparent '"hen it was reulized t he spe­ cies occurs f rom the R ed Sea through most intet·,·ening a reas to the ITawaiian I la nds and that its eastward cxtr nsion to many points in the Pacific Ocean was solely to utilize it as a food staple. It i:s a par ticularly important food item in pa11 s o( India. It was readily taken in harbor wa ters bordering the ecologic area and in connecting ponds and estuarie. with simple rircular crab n f:' ts baited with meat. Unlike the other portunicls, which wer e often seen in shallow water n ear shore, • . sCI'I'ala seemed to prt>fcr deeper water . Individuals taken in stl'eams flowing in'to the hnl'­ bor wcl'c invariably small. The only specimen srcn to voluntarily leave 1he water was the old adult mentioned in the discussion of 1/ erpestes mungo anu his was a ease or l1C(•cssity. :Han W

only enemy of the species in this nrea, for even small Snrnoan crnbs were well-equipped to defend themselves against other spe­ cies of crabs. The hardiness of the animal was attested by the fnct that it often survived "·it hont wetting for twenty-fum hours anu longer, while both l!oclo phthulm.ns 1:igil and Nepttmns san­ yuinolentns rapidly died when taken out of water. Like the otber species, S. se?Tato. was a scavcngcl' and despite its massive anna­ mont which made large individnal s dan ge~:ous unless handled properly, it \\'t. The color was reddish without diversification ; a distinctive fea­ ture 11·as the extremely long-stalked eyes which originated ncar. the fronto-mcclian line of the carapace and, \l·hen retracted, lay in grooves extending nearly the entire length of the carapace front. Wl1 en foraging, the anima] carried its eyes elevated at vTl·:s 109 c· l aw~. In auolht•t· iustanre, an etfltally m1w11r.'· ~pecimrn was ranght by a momwose (. ee llcrpl sics 11/llllfJO) while feeding too <'lose I o shore.

'l'IH' ,·olumiuons shol'e r rah famil~· Ur·npsidat• hau one species in th e Yi(·inity, the wide-S}1J'eacl .llclopogmp.ms m es.~or, an lw bi Inc 0 I' llllldd~ · shores. :.\l ost indiY idnaJs seC'Illl'd to spellll as mtwh time out of' water as iu, ;mel bul'l'owcd profnsrly in sort muddy banks ll tHl under roeks. A ty pi ('ll I sea vcnge r. t lw spe<' ies was

The mcnt ioncd ~h rimp I>alncmon del1ilis ( Palacmoni tl:ll') oc­ t·urrrd in \'<1St numbers in the har·bor, pond. . 11 1111 streams anti was probably thr mo. t important food I'or st•Yera l Joe a I Yat'it>t i<'s o[ fishes. Groups of t he sleeper Eleoll'is fu .~c a ( Elcot r·ida(' ) ortc•n pm·sued these <·r·nstat-ea ns, ca-using- them to 1Jl'E'HI{ wal<'l' in large numht•rs in t'r·a ntic elfot·ts to escape. Two mosquito fi sh. Oam­ lnu;ia a flini.~ and ,lfollil'nisia lafipimw ( Pot•cilitlac) '''(' J'<' seen to feed 011 imnHI(lll'C shrimps; the Pl'CS(' IJ (•(' or 1hons:IIH1s of P. d

The 1sopotla, tt•rrcstrial 'rustrt<'<'ll. W<'l'<' r·t•pr·rs<>nft•d b;\- I wo famili1•s, Oniscidae and Li l? ~-dida e, indi,·iduals or whi<·h w<'J'<' ex­ t r·emcl~- nnmCJ'Oll>.. JAgyda rJ'rnll,,· swi rt wlwn tl i. ­ lnrbNl, and a problem to ratrh .•\11 wet'<' impOI'tant foocls ror m a n~· other· animals.