Papilio demodocus (Citrus swallowtail)

Life > Eukaryotes > Opisthokonta > Metazoa (animals) > Bilateria > Ecdysozoa > Panarthropoda > Tritocerebra > Phylum: Arthopoda > Mandibulata > Atelocerata > Panhexapoda > Hexapoda > Insecta (insects) > Dicondyla > Pterygota > Metapterygota > Neoptera > Eumetabola > Holometabola > Panorpida > Amphiesmenoptera > Lepidoptera (moths and butterflies) > Glossata > Coelolepida > Myoglossata > Neolepidoptera > Heteroneura > Ditrysia > Apoditrysia > Obtectomera > Macrolepidoptera > Rhopalocera (butterflies) > Superfamily: Papilionoidea > Family: Papilionidae > Subfamily: Papilioninae > Genus: Papilio

Papilio demodocus (Citrus swallowtail)  

Papilio demodocus (Citrus swallowtail) female, Manguzi. [photo Steve Woodhall ]

 

 

 

 

Adult. The female is larger than the male and the anterior blue spots of her hindwings (obscured here) have orange on the outer side as opposed to yellow in the male.

Mature larva. Larvae take about a month to develop, passing through 4-5 instars and reaching a maximum size of about 45 mm.

Pupa. The caterpillar spins a mat of silk on a twig or leaf of the host plant to which it attaches the tip of its abdomen. It pupates within 2 days, first spinning a girdle of silk to hold itself in a slanting position. The pupal period lasts 2-3 weeks.

Eggs. The female settles on the leaf of the host plant and, while still flapping her wings, bends her abdomen downwards on to the leaf surface and lays an egg. Egg development takes about 6 days under warm conditions. The larva eats it way out of the egg and then consumes the remains of the egg shell.

This is the common, large black and pale yellow butterfly seen regularly in gardens in South Africa and also occurring in natural vegetation. It occurs in open, often disturbed, habitats throughout Africa south of the Sahara, as well as on the Cape Verde Islands, Madagascar and Mauritius (Ackery et al. 1995).  It can be a pest of citrus saplings in nurseries and, although found on mature citrus trees, does not cause sufficient damage to warrant instituting control measures. On young plants, if larvae and pupae do reach high levels, the best control procedure is evidently to simply pick them off by hand.

The Citrus swallowtail passes through about three generations during spring, summer and autumn, and the winter period is usually spent hibernating as a pupa. One can, however, see the occasional adult during winter.

Natural enemies

  • Eggs are parasitised by a small wasp Ooencyrtus.
  • Pupae are parasitised by the wasp Pteromalus puparum (Hymenoptera: Pteromalidae).

When the mature larva is disturbed by, for instance, a bird, it rears up and uses blood pressure to squeeze out a forked, finger-like orange-coloured organ called an osmetrium from just behind its head. Besides the visual impact of the organ, it also has a strong smell which acts as a further discentive to the predator. The smell is evidently caused by accumulation of substances from the oil glands in the leaves of the host plant. t is thought that it is this osmetrium that gave rise to the term Orange dog for the caterpillar.

The young caterpillars are protected by camouflage, their black, yellow and white colouration making them look like bird droppings.

Host plants (information mainly from Kroon, 1999)

  • Anacardiaceae: Pseudospondias sp. 
  • Apiaceae: Archangelica officinalis; Deverra burchelli, Fennel Foeniculum vulgare, Blister bush Peucedanum galbanum, Peucedanum gummiferum, Pituranthos burchellii.
  • Ptaeroxyylaceae: Ptaeroxylon obliquum (=P. utile)
  • Rutaceae: Cape chestnut Calodendron capense, orange and lemon trees Citrus spp., Clausena anisata (=C. inaequalis), Fagara capensis, Oricia bachmannii, O. swynnertoni, Teclea natalensis, Teclea swynnertonii, Toddalia aculeata, Toddalia asiatica, Vepris lanceolata, Zanthoxylum capense, Z. delagoense
  • Sapindaceae: Hippobromus pauciflorus (=H. alata)

References

  • Ackery, P.R., Smith, C.R. and Vane-Wright, R.I. 1995. Carcasson's African Butterflies. An Annotated Catalogue of the Papilionoidea and Hesperioidea of the Afrotropical Region. CSIRO, Australia.

  • Annecke & Moran (1982)

  • Claassens, A.J.M. & Dickson, C.G.C. 1980. The Butterflies of the Table Mountain Range. C. Struik Publishers, Cape Town.

  • Clarke, C.A., Dickson, C.G.C. & Sheppard, P.M. 1963. Larval colour pattern in Papilio demodocus. Evolution 17: 130-137. [not consulted].

  • Kroon, D.M. 1999. Lepidoptera of Southern Africa. Host-plants and other Associations. A Catalogue. Lepidopterists' Society of Africa, South Africa.

Photographs by H.L. O'Heffernan; text by Hamish Robertson


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