INTRODUCTION OBSERVATIONS

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NATURE IN SINGAPORE 2011 4: 369 375 Dte of Puliction: 28 Novemer 2011 Ntionl University of Singpore OBSERVATIONS OF PUPAL ECLOSION AND PHEROMONE RELEASE IN THE OLEANDER HAWKMOTH, DAPHNIS NERII

1 NATURE IN SINGAPORE : Dte of Puliction: 28 Novemer 2011 Ntionl University of Singpore OBSERVATIONS OF PUPAL ECLOSION AND PHEROMONE RELEASE IN THE OLEANDER HAWKMOTH, DAPHNIS NERII (LINNAEUS, 1758) (LEPIDOPTERA: SPHINGIDAE: MACROGLOSSINAE) Tzi Ming Leong Deprtment of Biologicl Sciences, Ntionl University of Singpore 14 Science Drive 4, Singpore , Repulic of Singpore (E-mil: INTRODUCTION The cterpillrs of the olender hwkmoth, Dphnis nerii (Linneus, 1758) were previously rered to metmorphosis nd riefly descried y Leong & D Rozrio (2009) sed on encounters in Singpore. A recent rering of the sme species provided the opportunity to document the precise moment of eclosion from the pup, s well s to oserve susequent ehviour of pheromone relese y the femle hwkmoths. OBSERVATIONS On 26 Sep.2011, n ggregtion of olender hwkmoth cterpillrs (out individuls) ws encountered on n olender ush (Nerium olender, fmily Apocyncee) growing long Est Cost Terrce. The cterpillrs were mostly in their finl instr nd feeding on the leves, s well s the flowers of its hostplnt (Figs. 1, 2). When distured, the cterpillrs would disply their chrcteristic defensive posture, tucking in their heds nd exposing the prominent ocelli on the third thorcic segment (Fig. 3). Four cterpillrs were collected to e rered in cptivity. The cterpillrs demonstrted helthy ppetite for the olender leves nd y 29 Sep.2011, pre-pupl colourtion nd ehviour were noticed. By 1 Oct.2011, the cterpillrs hd lredy completed puption. Fig. 1. Finl instr cterpillr of the olender hwkmoth, Dphnis nerii, perched on its nmeske hostplnt, Nerium olender (Apocyncee) growing long Est Cost Terrce on 26 Sep Its ody length ws c. 75 mm, with til horn 4 mm long. 369

T3 Fig. 3. Typicl defensive posture of the finl instr cterpillr (ody length 80 mm).

2 Leong: Pupl Eclosion nd Pheromone Relese in Dphnis nerii Fig. 2. Anterior close-up of finl instr cterpillr (s in Fig. 1) feeding on flower uds of Nerium olender. T3 Fig. 3. Typicl defensive posture of the finl instr cterpillr (ody length 80 mm). With its hed tucked ventrlly, the prominent pir of ocelli (ut only one ocellus shown here) on its third thorcic segment (T3) is clerly displyed. 370

NATURE IN SINGAPORE 2011 On the evening of 11 Oct.2011, the pupe displyed signs of imminent eclosion, s the pupl cuticle hd turned trnslucent nd ws delicte to the touch.

3 NATURE IN SINGAPORE 2011 On the evening of 11 Oct.2011, the pupe displyed signs of imminent eclosion, s the pupl cuticle hd turned trnslucent nd ws delicte to the touch. At this stge, the symmetricl rrngement of its first two pirs of lims nd wings could e redily seen inside (Fig. 4). The intersegmentl memrne of its domen lso ppered slightly swollen nd distended. The first two hwkmoths emerged t c nd 2100 hours, ut the moments of eclosion were not witnessed. Close ttention ws then ptiently focused on the third hwkmoth, which eventully eclosed t precisely 2252 hours (Figs. 5, 6). The first splitting of the pupl cuticle ws preceded y noticele movements of its fore- nd midlegs. In prticulr, the midlegs pper to ply pivotl role in lifting wy the nterior thorcic shield piece. Within 10 seconds, the ody of the hwkmoth hd dvnced forwrd, with its hed entirely removed from the cephlic helmet, nd its ntenne, eyes nd prooscis were clerly visile (Fig. 5d). Twelve seconds fter the strt of eclosion, its wings hd ecome fully lierted from the pupl cse (Fig. 6). Shortly fter, the hwkmoth quickly extricted itself nd dopted n upright posture to scrmle wy in serch of the nerest possile perch (Fig. 6). In totl, the entire eclosion process ws completed in c. 18 seconds. Therefter, the hwkmoth ws provided rnch on which to extend nd stiffen its wings (Fig. 7). All four of the hwkmoths successfully eclosed eventully nd were found to e femles. Two specimens were preserved soon fter eclosion, while two others were kept live for susequent oservtion. After two dys, the hwkmoths were oserved to rch their domens while perched. Distlly, golden rown glnd ws extruded, nd upon close exmintion, slow nd delierte pulstions of the dorsl memrne could e detected (Figs. 8, 9). The rhythmic contrctions of this pheromone glnd rnged etween pulses min 1. A video clip of this process of pheromone dissemintion ws recorded nd uploded online ( The extrusion of the pheromone glnd, ccompnied y regulr pulstions occurring two dys post-eclosion my e n indiction of necessry period for ov mturtion prior to femle receptiveness (I. J. Kitching, pers. comm., Oct.2011). The femles continued to exhiit such pheromone-relese ehviour for t lest three consecutive dys, etween c hours. They were susequently preserved s voucher specimens nd deposited t the Zoologicl Reference Collection (ZRC) of the Rffles Museum of Biodiversity Reserch (RMBR), Ntionl University of Singpore, where they re collectively ctlogued s ZRC.LEP.358 (ody lengths: mm, forewing lengths: mm). W L1 Fig. 4. Ventrl close-up of the nterior segments of the pre-eclosion pup. The pupl cuticle hs ecome trnslucent, enling cler views of the underlying wings (W) nd nterior two pirs of lims (L1, ). Photogrphed on the night of 11 Oct.2011 (2230 hours). 371

4 Leong: Pupl Eclosion nd Pheromone Relese in Dphnis nerii L3 c d Fig. 5. Pupl eclosion sequence witnessed on the night of 11 Oct.2011, t 2252 hours: c, t 4-second intervls; nd d, fter 2 seconds. nd L3 refer to the second nd third pirs of legs respectively. 372

hwkmoth righted itself nd crwled wy hurriedly in serch

5 NATURE IN SINGAPORE 2011 Fig. 6. Continution of pupl eclosion sequence (from Fig. 5) on 11 Oct.2011, t 2252 hours fter 6-second intervl, when the hwkmoth righted itself nd crwled wy hurriedly in serch of the nerest perch. Fig. 7. Freshly eclosed hwkmoth (s in Figs. 4 6) extending its wings:, t 2255 hours; nd, t 2300 hours. 373

6 Leong: Pupl Eclosion nd Pheromone Relese in Dphnis nerii Fig. 8. Dorsl () nd lterl () close-ups of the extruded pheromone glnd of femle hwkmoth (ZRC.LEP.358, ody length: 44 mm, forewing: 42 mm), first oserved on the morning of 14 Oct Slow nd delierte pulstions of its dorsl memrne were oserved (15 17 pulses min 1 ). 374

7 NATURE IN SINGAPORE 2011 Fig. 9. Ventrl close-up of the extruded pheromone glnd of femle hwkmoth (s in Fig. 8). ACKNOWLEDGEMENTS I m grteful to In J. Kitching (The Nturl History Museum, London) for vlule insights into the structure nd function of the pheromone glnd of the hwkmoth. The efficient review nd helpful suggestions from n enthusistic lepidopterist were much pprecited. LITERATURE CITED Leong, T. M. & V. D Rozrio, Finl instr lrve nd metmorphosis of the olender hwkmoth, Dphnis nerii (Linneus) in Singpore (Lepidopter: Sphingide: Mcroglossine). Nture in Singpore, 2:

FINAL INSTAR CATERPILLAR AND METAMORPHOSIS OF LEBEDA COGNATA GRÜNBERG, 1913 IN SINGAPORE (LEPIDOPTERA: LASIOCAMPIDAE)

NATURE IN SINGAPORE 2012 5: 129 140 Dte of Puliction: 4 My 2012 Ntionl University of Singpore FINAL INSTAR CATERPILLAR AND METAMORPHOSIS OF LEBEDA COGNATA GRÜNBERG, 1913 IN SINGAPORE (LEPIDOPTERA: LASIOCAMPIDAE)