Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.
Behavioural ecology and prey attraction of the New Zealand Glowworm Arachnocampa luminosa (Skuse)(Diptera: Mycetophilidae) in bush and cave habitats.
A thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University
Richard Adam Broadley 1998 To my father Ill
Abstract
Larvae of the mycetophilid Amch11 ocu111pa /11111i11osa (Skuse), known commonly as "glov.rworms", inhabit
damp, she lt ered and shaded places in bush, and caves. The glO\nvorm is predaceous, and it li ves wi thin a
mucus tube or gallery from 11.foch hang 1·enical .. fishing lines .. made from si lk and sticky mu cus.
lmenebrates are captured 011 the fishing lines and hauled up by th e larva and eaten .
Glo11·11orllls USC biolulllinescence to attract inn::nebrates I tested the effecti1·eness or bioluminescence by comparing the numbers of i1ll'enebrates caught on trnn sparent adhesi ve traps placed over glowworms with simi la r traps set over ar<.'!a s that glowworm s had been removed from . Prey attrac ti on was in ves ti ga ted in
ReserYc Ca1·e. \\'aitomo. and in its bush-clad entrance 01·er 200 davs durin~ "11·inter'', ··spring·· and
summ e1 Traps placed O\·er glo w1,orms caught signi licant ly mo1·e i1ll'ertebra1es overa ll per trap per cla y than control traps Glo11worms in bush attracted both greater numbers and types of in vertebrates than gl01H1orms in the can'. There 11ere also signifi cant seasonal differences in the numbers caught and types of im ertebrates Fl) ing Di pt era predominated in both bush ( 8)%, of the total catch) and cave (89%) habitat s.
Minor components consisted mainly of spiders (Araneae), Coleoptera. Hymenoptera, Orthoptera.
Trichoptera, Gastropoda. Acariformes and Neuroptera Confi rm at ion that th e attracted invertebrates were eaten by glowworms was demonstrated by collecting and examini ng glowworm faeces and ident ify ing discarded material from th ei r snares. Thi s was done by plac in g blotting paper sheets under glowworms in cave and bush habitats during spring and summer. Mo st faeca l material consisted of insect sensi ll ae and spines. cuticle and compound eye cuticle, but discarded legs, antennae and wi ngs were sometimes present either as parts or entire. Entire or fragmented millipedes were sometimes present, especiall y in the cave.
Occasionally in sect head capsul es, thoraxes and abdomens were also discarded. Several sma ll snail shell s
(Gastropoda) were found under bush glowworms and three entire insects were found under glowworms in the cave in summer. No adult A. /11mi11osa were caught on adhesive traps, or identified in the material discarded from glowworm snares. Glowworms under adhesive traps appeared to be able to survive for long periods without food, especially those in the cave, which all survived with little or no food for 78 days
At Waitomo, variation in light output by different glowwom1s affected the number of invertebrates that were attracted to the light and increased the variance in prey numbers between different glowworms. This was overcome at Waitomo by running the experiment for long periods of time in order to demonstrate attraction.
Using live glowworms in such experiments was also labour intensive and time consuming. A light-emitting diode (LED) with a similar maximum wavelength to glowworms was used, to explore the possibility that it IV
could be used to sample the potential food of glowworms in areas where glowworms do not occur, such as
some passages rn caves. The suit ab ility oft hese LEDs were tested by comparin g catches in ad hesive traps
containing them with traps containing glow\\orms and traps \1·ithout (co ntrols). These were run in bush for
2 I days and then a Ji.in her 2 I da\ s in a caw passage at Pi ripi ri Road Caves, Pohangin a Traps wit h LEDs
caught a significant!\' greater total number of ill\ enebrates overall than traps either wi th or v-i thout
glow•vo rm s. l lowe\·er, there \vere no signifi cant differences in th e numbers of Mycetophilid ae, other Dipt era
familie s and other in\'ertebrates caught on the three trap t\ves in bush or in the cave.
The prev recogni tion hcha\·ioi 1r of' .-1. /111111110.'u Ian ae i1l\'Ol\'C s taste and/or smell Th is \1as demonstrated by
co mparing th e numbers or Jin~ ;rnd dead l>roso11hilu 111 1.'!u11ogw1a, and bl o11ing paper that \\'as both dry and
soaked in crushed /J. 1111.'lu11ogw1crjuicc. that \1ere "hauled-u p". "discardecf', "left hanging" or .. llli ss ing .. the da\' after th e\· \1erc placed on the 1·enica l fi sh in g lines of larYal snares. There were signifi ca nt differences
bet\vce n responses or glow11 onns to dr1; paper. \1 et paper. and dry paper placed abo\·e I>. 111.:lu11 ogmNr on fishing lin es \ ·lost (72° o) or th e pieces or paper \\ ith cru shed /) 111 elu11og11.1'/er juice were hauled up in to glo11worlll snares. and none \1 ere discarded. \\ hereas dry pieces or paper were found haul ed up 16% of the tillle but -W 0 oof them had been discarded.
Remote recording of A . /11111i11osa in both bu sh and ca\·e habitats at Wai to mo was done between 18/ I/ 95 and
19/ I I /95 Observations were made using infra-red light and a TV camera which was sensitive to thi s light
A total of 934 individual ''larva-ho urs" of ac tivi ty were record ed, in clu din g 308 "larva-hours" of 4 glowworms in bush ~ 345 "larva-hours .. from 4 glowworms in Demonstration Chamber of Glowworm Cave;
233 '"larva-hours" from one glowworm in Reser\'e Ca,·e; and -!8 hours of several glowworms in Waitomo
Waterfall Cave. Observations were also made of three adults emerging from their pupal exuviae. A male adult was observed al ighting upon a female whi ch had not glowed for abo ut 53 minutes, and the pair copulated. This provides evidence to support the suggesti on that adults may use olfac tory organ s in mate attraction. After copulating they were both eaten by a large predatory harvest men (Mega!opsa/is tumida
Forster). As a resu lt of vid eo-tapi ng A. /11111 i11osa many observati ons were made and many types of behaviour were id entified. The most obvious ones were production of bioluminescence, "fishing line construction", "defecati on", " fi ghting" between pairs of larvae, "prey capture", and attempted capture of in vertebrates by larvae. Behaviours recorded rarely were the eclosion of both male and female adult A. luminosa from pupae, mate attraction, and copulation. Glowworm larvae in bush glowed only at night.
They usually became active late in the afternoon when they began to make fishing lines, repair snares, and void defecatory droplets. They started to glow up to an hour and a half after becoming active, and they v
turned on their biolumi nescence relati vely quickly, from less than I 5 seconds to about I minute for a bright
li g ht to be ,·isible. At da v, n. glowworms in bu sh took several minutes to fa de out their lights, but on cold
night s (- < 6 ° ( ) the,· glo11·ed onlv int erm itt ent h" or not at all . Larvae in the Demonstra ti on Chamber
appeared to be disturbed b' ca\t' ligJ11s and win d currents apparentl y generated by the acti,·ities of humans in
the re \\'he n ca,·e lights ''ere s11 itc hed on for more than about 30% of the time (- 20 minutes per hour).
larvae did not glo11 bright I\ and spent littl e time making ti sh in g lin es ( < 5° 0 of tim e per hour) I lowe,·er.
th ere is no 11a\· to be cenain ii' thi s distu rbance \1a s det ri men tal to their o,·eril ll 11ell -bein g The lanil in
Resen e C;iw glo11 ed on a\ cragc onh" bet 11 een 1.1 t1CI and o:: 00 on onh- fo ur out of eleven da\'S, and did no t appear to glm1 brighth· cnmparl'd 11 it h glo1111o nm eit her in bush or in Gl o,1·1, orrn Ca,·e . Ho'' e"er. it ''as
not possible to determine 11hethcr t hi ~ be ha,·iour ll ilS t\·pical or other glo1111onns li \ ing in th e Ca\·c Onk one obsel\a1inn or pre,· capture \1as made. 11 as at tacked bY a glo 11 11 orm 11 hen it touched it s snare. but it wa s strong enough to brea k free Fi ghting bell\ een lan ·ae usuall y occurred when a lal'\·a 111 01·ed pa rt-11 a~ · out o f its gallery to search the sub strate fo r new point s of att ac hment fo r it s snare and fi shing lines, and then accid entally touch ed the snare of it s neighbour Thi s ind icates tha t larvae fi ght to in crease th e size of th eir territ orv or to pro tect their mrn territory. Fighting larvae glowed brilliantly and 11 ould snap at each others heads with their jaws, and occasionall y tried to pull each oth er out of their snares These fightin g episodes usually concluded when one of the larvae retreated, but often the fi ght s would resume so me time lat er. Larval canni ba li sm wa s not observed, although on one occasion a Jarva was bitten on its body by an intruder wh ich had mo ved completely out of its snare. Defecation was obsef\·ed on ten occasions In bush, larvae either voided excretory droplets out of the snare or produced them so they hung on fi shing li nes . In the latter case the larvae then lengthened the fishing lines until the droplet s made contact wi th the substrate. In caves the glov.'Worms cut and dropped entire fi shing lines wi th droplets on them, or they left them hanging within the snare. Starch-gel electrophoresis of allozymes showed that populations of glowworms tend to be genetically di screte but with no particular geographic or ecological structuring between them. This was demonstrated by collecting A. luminosa larvae from many cave and bush sites in the North Island. Average Standard Genetic Distances between populations were determined (Nei, 1975) and the results were subjected to V I cluster analysis using average pai1 group clustering with the package M .V .S.P. This shov.ed that geographically adjacent glo\\ \\ orm populat ions did not tend to be more similar genetically than distant populat inns and tlrnt gln\1\101111 populntion::. did not ciuqer into bu ~ h and ca,·c popul11t ions I IO\\ C\·er. the gene lkm occuh regular!~ bet\\ cen glo\\ \\ orm population~ . and doe~ not ~uppon the notilrn that cn1 e and bu'h 1{11111 s should be 1ega 1dcd il'i di:,tinct ~pccie<; or 'ub~pecie~ Vil Acknowledgements Fi na ncial support for thi s research was prO\'ided b\' the (fo rmerl y) T.H C. Wait o 111 0 Caves Hotel, Waitomo Ca\·cs Management Comlllittee. Ruapuha uekaha Hapu Tn1 st. Department of Ecology at Massey Uni versit y. and a graduate rcsea1·ch a\1;ml fro m the \ fasse\· L:ni\ersit\· Graduate Research Fund . Without the h:ind help or all or the fo llowing people thi s \\ ork would 110( ha\'e been possible - to all of yo u. thanks a lot Bn son ,\nderson fm sho\\ing nit' the gl mn1 o r111s up at \Vaituna \\'est ; Ian Andrew and Jay rv1cC111ne\· ;i; ;\Ja~sey k1r ic!enti1~ ' ing ill\ertebrates John A~ h a11d l'ete Chand ler and gu ides or 131 ac h: wa tcr Rafting for lo \idc'u tape~ . ,\ Ian Cnrpenter and (';i5e \'iln [pcnhauscn for prO\idi ng me \1 ·ith a buc h: et rull of insect ad hesive ;it short notice; Kate I3 anburv for informa ti on rega rding lighting in Gloll'worm Cave; Stuart Burgess at th e Nat ional Insti tute of W;iter and Atmospheric Research Ltd (\.; IWAJ in \\'ell ington fo r Wait omo rain fa ll darn. Nicc i Coffc\ ror helpi ng to lu g equipment into ReSCl\C Cl\c; Peter Dimond fo r hi s hospit alit y and for pro\ iding Ille \1ith space fo r all my gear in the \!useum of Cm es and use of th e workshop there: Allan Goss for allowing me to conduct resea rch on hi s land at Piri piri Road Caves: Sac ha Hall at th e Carter Observatory in \Vellington fo r vari ous atmospheri c da ta: Sh ane Hatcher for providing limitless supplies of Umsophi/u at a momen ts not ice; Ian Henderson for much-needed help \1 ith stati stical analyses; Dave Hurst for help co ll ecting sampl es in th e fi eld and caving adw ntures; Jens Jorgensen fo r co nst ru cting variou s ingenious pi eces of equ ipment from scrap materi al; Bruce Rapl ey, Dex ter Muir, and Wya tt Page fo r their kind help with const ru cting the ca mera casing, infra-red light sources. li ght tra ps and vari ous other pi eces of equipment , and fo r teaching me some useful skill s i e. how to use a lathe and a soldering iron; Oliver Paskins for helping collect inverts off adhesive traps and insect collecting expeditions; Steve Pilkington for providing transport to get most of the gear up to Waitorno; Chris Pugsley for some brain-picking and use of his cave map; Ray Scrimgeour of DoC Te Kuiti for giving the all clear to conduct research at Reserve Cave; Ashley Shaw of the New Zealand Speleological Society for permission to use cave maps; Allan Singleton at NIWA for providing me with atmospheric data for Glowworm Cave; Dave Smith for a guided tour around several caves at Waitomo; Cam Speedy of Department of Conservation Taupo/Tongariro Conservancy for granting me permission to collect glowworm samples from Okupata; Robert Tahi and guides of Glowworm Cave for advice and assistance; Tamsin Ward-Smith for her help and assistance; Dave Williams, former manager of the Waitomo Caves Hotel for allowing me to stay at the cottage for free throughout the field work and for much Vlll needed local kn owledge; and to the many travellers I met at the hostel and everybody else who took an int erest in 11 hat I 11 as doing. and lent a hand Thanks cspecialll" to rnv fiunil\' for their suppon . and to rn1 superviso rs Dr Ian Stringer and Dr Alastair Robenson. 11 iw illlrnducc:d mew a bri lliant thesis iopic. Contents Page Acknowlrdgrm r111 ~ \'II GENER·\L l\TRODl.CTIOi\ 2 PREY .-\TTR.-\CTIO.\ BY GLO\\\\OR\IS I\ .-\ C.-\ \ T :\1\0 I:'\ TllE IWSl-f 4 CL.-\D C \ \T E:\TRA'.\'CE Int roduct il)ll ;\latcrial,; & \lc1h ,1 d,; Result s Di scu,,;il)n 3 ATTR.\CTIO\ OF l\\TRTEBR:\TES TO GLO\\\\ OR.\JS :\"'O ARTIFICIAL 27 LIGHT SOt'RCES :\T PIRIPIRI ROAD CA YES, POH.\ J\GL\'.-\ Introduction 27 l\1a1criab 8:. \ lct!H.• ds 31 Results 36 Di scussion 41 4 PREY RECOG\ITION BY GLO\\\\ORMS 4-t In troduction 44 Materials 8:. l\kthods 45 Result 49 Di scussion 52 5 OBSERVA TIO:'\S DERIVED FROM REMOTE RECORDING OF 55 ARACH/\'OCAMPA LUMINOSA l N BUSH AND CAVES AT WAITOMO Introducti on 55 Materials & Method 57 Results 64 Discussion 92 Appendix 96 6 AREARACHNOCAJHPA LUMJNOSA JN BUSH GENETICALLY ISOLATED 97 FROM THOSE FOUND lN CAVES? - AN lNVESTIGA TION USING ALLOZYME ELECTROPHORESfS TECHNIQUES Introduction 97 Materials & Methods 99 Results 106 Discussion 111 Appendix 113 References l18 List of Figures Page I. I Gl owworm s and their snares. 2 I " An adu lt A. /1 1111i110 , a ma le clings to a female pu pa . Loca ti on of Resen·e Cim.> and the bush sites in Ru ak uri Sce nic Reserw. \\'a it omo 7 ') ') t\ ' ie'' from inside R c~c 1 Ye Ca ,·c \\'aiwmo, of th e bu sh-c lad ca ,·e cntnrnce 8 ') ' C location or blotting paper shceh used to co ll ect glo " \\ orm faeces and cliscarckcl material I 0 Log lllll11 bers or in w rtebrat es co ll ccred per da y fr om adh csi\'C tra ps in Rcserl'C Ca,·e 12 and in the bush-clad entrance to Resen ·e Ca\·c, \\·ai tumo, m·cr 11·int er, ~pring and summer 2.6 Relati \·e num bers of im·en ebrates caught per da y on tra ps co nt aining gJo,1worm s and 16 cont rol traps in the bu sh-cl ad ent ra nce to Reserve Cave. Waitomo, during \vinter. spring and summer. 2.7 Relative numbers of in vertebrates caught per day on tra ps co nt aining glov.worms and 18 control traps in Reserve Cave, Wait omo, du ring wint er, spring and summer. 3.1 The li ght sensit ive phot oswitch setup used to swit ch LE Ds on at dusk and off at dawn 29 at Piripiri Road Caves, Pohangina 3.2 Circuit di agram of the li ght-sen sitive photoswitch used in Figure 3. 1. 30 .,., 3.3 Locati on of both bush and cave sit es at Piripiri Road Caves, Pohangina, where ·'-' invertebrates were collected from adhesive traps containing 4 70 nm LEDs, glowwom1s and from areas where glowworms had been removed from . 3.4 Diagram of watertight LED tube used to attract invertebrates at Piripiri Road Caves, 34 Pohangina. 3.S Bush location at Piripiri Road Caves, Pohangina, showing all 18 transparent adhesive 35 traps wired onto the rock face. List of Figures cont'd Page :> .6 Tim e c.xposure of the bush location at ni ght. shO\\ing the loca ti on of both LEDs and :;5 some or the glO\\\\ orn1s \·I it bin adhesi1·e traps 4. 1 Map ofGlo\1\1'onn Ca1·e, \\'a it omo. sho\1ing the locat ion orthc tu nnel ceil ing sire -1 6 \I here glo\n1 or ms \1 ere rc11101 ·ed for pre\' recognition experiments Diagram of an obsc1Yat ion chamber. cons1ruc1ecl frrnn an i1ll'c n cd I "litre transparent -17 pl as ti c sot1-drin1' bottle with it s top cut off used 10 hou .,e a glo11 \I orn1 i conduc1i ng pre1· recogni tion experime111, Equipment u~cd to record A. /11111111u'u at brnh J> u,h and cm·e sites a: \raitomn Location oft he site in Demonstra ti on Chamber. Glo\1 \10rm Ca\·c. \\·aiw1110 . where remote recording or A. 1!11111110"1 tnoJ..: place 5.3 Local ion of bo th bush and ca1·e sit es at Re sen e C a1 e, \ \'ai tomo, where remote 60 recording of.i. !t1111i11osu pupae, adul ts. and a single Ian a tooJ..: place 54 Location of t he site in Wait omo \\'aterfa ll Cai e. \1 here remote recording oL-1. 6 1 /11111i11 osa too J..: place. ) 5 Location of Glowworm Cave, Reserve Cave. and the bush sit es in Ru al-:uri Scenic 62 Reserve, Waitomo, where remote recording or glowworms took place 5.6 Mean hourly percentage of time two larvae spent glowing in bush at Ru akuri Sceni c 65 Reserve, Waitorno, between 23 and 25/2/95 5.7 Mean hourly percentage of time two larvae spent glowing in bush at Ru akuri Scenic 66 Reserve, Waitomo, between 9 and 15/5/95 . 5 8 The possible effect of temperature on the percentage of time per hour A. luminosa 67 larvae were observed to spend glowing in bush at Ruakuri Scenic Reserve, Waitomo. Temperature measurements were taken each hour in bush outside the entrance to Glowworm Cave approximately 2.5 kilometres away. List of Figures cont'd Page 5 9 Mean percentage oft ime per hour that fo ur A. /11111111 0.'ll larvae spent glowing brightly 68 in De 111 onstrati on Chambe r of Gl 01111or 111 Ca1 ·e, Waito 111 0 Obsen·ati ons were taken bet1veen 2 - 5/4/95 and 19 - 2:0 6 9~ 5 10 Rel ati onship between th e mea n perce nt age of time per hou r spent by four A. /11111i11osll 69 lan·ae gll1\\ing bright II' in De111 0 11 s1rat io 11 Cha mber o( Glo1111 or111 Cilvc, Waitomo, and th e mea n hourl y percen iage 0!'1i 111e tha t the ca1e lights 11erL' '\\itch1::d 0 11 Ohscn ati ons 1v ere mack bet1Vee n 2 - ' i-1 /9) a 11 d i ') - 23 ' rJ' " 11 l\ 'lea n pcrceniage of time 011e .-L /;1111111wu la1 n1 spem gl o 11 ing per hou r in Rcsen e 70 Ca1t>, \\'i! it omo Obscr1a tio 11 s 11ere mad e hl-111een 7 - I lJ 11 0' 5 12 l\'l ean hourl v percentilge of time spent b1· t\\ l) .·J. /11m 11111 1u lar1 ae constru cting fi shing lines in bu sh at Ru akuri Scenic Reser1e. \\'aitomo. bet11 ecn 23 - 2'\ 2/95 5. I J l\1ean hourl y percentage of tim e spe nt b1· t11 0 .-1 . /11111 i111N1 Ian ae constructing fishing 7-1 lines in bu sh at Ruakuri Sceni c Resene. \\'ai10111 0. bern ee11 9 and I S/ )!9S. 5. 14 J\1ean percenti!ge of time per hour spent by four A. /1111111111su laiYae construct in g 75 fishin g lines in the Demonstrati on Chamber ofGlo\\11 o r111 Cave. \\'aitomo, between 2 - 5/4/95 and 19 - 23 /5/95. The mean percentage oftime "hen th e cave lights were switched on is also sho1rn. 5. 15 A. /11111i11 osa larva constructing a fi shing lin e in Dem onstrati on Chamber of Glowworm 76 Cave, Waitomo. 5. 16 Relationship between the mean percentage of time per hour spent by four A. /11111i11 osa 77 larvae constructing fishing lines and the mean hourl y percentage of time cave li ght s in Demonstration Chamber of Glowworm Cave, Wait omo, were switched on, between 2 - 5/4/95 and 19 -23/5/95 . 5.17 Mean hourly percentage of time spent by one A. /11111i11osa larva constructing fishing 78 lines in Reserve Cave, Waitomo, between 7/ 11 /95 and 19/11/95. 5.18 In bush at night a small fl yi ng insect is caught in glowworm fishing lines. 82 5.19 In bush at night a spider is attacked by a glowworm. 83 List of Figures cont'd Page 5 20 A pair of A. l11111 i11osa laP;ae fig hting in Demon st ra t ion Chamber or Glowworm Cave. 85 " .21 Glm\'\rnrm \ oiding an e'\cretory droplet onto the sub strat e bei 6 1 Loc;i ti on of sites in GIOW\\ Or111 Ca\'C, \Vait omo. \1 here glo\1worms \\'ere remo\'ed 100 from for all ozymc electrophoresis e:xperiment s 6 2 Locati on of t he site in Ru al\uri Scenic Resen·e. \\'aitrnno. 11 here glm111or111 s 11ere 10 1 1-e111 0\'ed fro111 fo r all ozyme el ectrophoresis e\pcri111 cnt s 6 3 Locati on ofthe site in Frn zers BluffCa,,e_ 01\upata. Tonga ri ro , 11hcr1? g lm111orms 102 6 -1 Location of the site in a tunnel passage at Piripi ri Road Ca,·cs. J> olrnng 1n a. 11hcre 103 g10111nmns 11ere re111ovcd from fo r all ozv111e clcctroph o r es i~ e\peri111 cnt s 6 5 Local ion of the bu sh site near Totara ReserYe. Pohangina, whL're glow11·or111s were 104 removed from fo r allozy me electrophoresis e\periments 66 Cluster analysis of Average Standard Genetic Di stances (D) between seven bush and 11 0 cave glowworm populations. List of Tables Page 2. 1 Analysis of Va ri ance of the numbers of inve rt ebrates caught per trap in bus h and cave 13 habitats, using traps occupied by glowworms or no glowv, orms (controls) during wi nter. spring & su mm er. 2.2 Invertebrates captured on traps pl aced over A. /11mi 11osu larvae and over ilreas 11 here 14 la1Yae ha1·e been remo ved fr oni. 2 3 Mean,. ranges and standa rd errors or nu mbers of inl'C·nebrates caught per day in 19 g!mn1 orm-occup ied trnps. 2.-l \kans. ranges and standard errors of numbers of droplets col lected per da1· per 20 glo11 worm from beneath glowworms. 2 5 Material iden tifi ed from blotting paper sheets placed under bu sh and cave glowworms. 2 1 3. Invertebrates captured on adhesive traps placed 01·er .no nm LEDs, glo11·1v orms and 36 01·er areas where glowworms have been rem01·ed . 4. 1 The statu s of prey items the day aft er they had been placed upo n glowworm fi shing 49 lines. 4.2 The statu s of li ve Drosophila mela11ogaster, dead IJ. 111 e/m1ogas1er and live n. 50 me/a 11ogaster hanging below pieces of paper the day after they had been placed on glowworm fi shing lines. 4 3 The status of pieces of dry paper, paper crushed in D. 111 e/a11ogaster juice and dry 51 paper hanging above live D. me/a11ogaster the day aft er they had been placed on glowworm fi shing lines. 5.1 Time (minutes) spent making fishing lines by glowworms in bush, Glowworm Cave 72 and a g!O\.vworm in Reserve Cave, Waitomo. 5.2 Means, ranges and standard errors of the lengths of time (h:mm :ss) that pairs of 84 glowworms were observed fighting for. 5.3 Means, ranges and standard errors of the lengths of time (h:mm :ss) glowworms 87 recorded at each location took to dispose of excretory droplets. List of Tables cont'd Page 6. 1 T he I 0 enzymes and their standard abb reviations, w hich glowworm samples were run 105 success full y in 6 .2 Frequency of all eles deri ved from running glowworm extrac t from severa l bush and 107 cave populatio ns in starch-gel electrophoresis, for I 0 enzymes . 6.3 Percent age of po lymo rphic loci ( P) and avera ge heterozygosity ( 11 ) for eac h 108 glO\\w orm po pu lati on 64 The a\·erage standard geneti c distance (D) be tween eac h g low\\'orm population, based I 00 o n all ele freq uencies from the I 0 loci (enz,rnes) Overleaf A boat-load of visitors gaze up at hundreds of pinpoints of bio/11minescence produced by Arachnocampa lurilinosa larvae in the famous grotto of Glowworm Cave, Waitomo (Printed by permission Waitomo Museum of Caves). XV I I wish I was a glowworm For they are never glum How can you be unhappy hen the sun shines out your bum? - Ricardo Palmer, Entomologist, Museum of New Zealand