Life history notes on the Striated Pearl-white, Elodina parthia (Hewitson, 1853) Lepidoptera: Pieridae - Wesley Jenkinson

This butterfly species, also known as the Chalky Pearl-white (and previously the Chalk White) is frequently encountered along much of eastern Queensland and into New South Wales. It is located in a varied range of habitats, having a preference for the drier forests and woodlands where it often flies with the closely related Southern Pearl-white (Elodina angulipennis), the Glistening Pearl-white (E. queenslandica) and the Narrow-winged Pearl-white (E. padusa). It is generally absent from the wetter rainforests and also penetrates inland west of the Great Dividing Range into the drier regions where the host plants are growing.

The adults have a more defined ‘chalky’ white appearance compared with the other ‘Queensland’ Pearl-whites and can be identified by the duller ‘striated’ pattern on the underside of the hindwing. The species is slightly smaller than, and is not related to, the well-known exotic Cabbage White butterfly (Pieris rapae), which has different wing markings and a different flight pattern.

Within Queensland, individual specimens show slight variation in the extent and shape of the black marking on the forewings. The species has both summer and winter forms with the striated markings on the hindwing underside being darker in intensity in the winter form. Some individuals have underside markings intermediate between the summer and winter forms.

Adult flight is fairly weak. Males can be observed patrolling forest margins while the females frequent the areas where the host plants are growing. They fly in sunny weather and often in warm cloudy conditions. During extremely hot temperatures the adults rest on leaves in the forest understorey, often close to the ground. The males often display ‘weak’ hilltopping behaviour and patrol glades just below ridge summits. Both sexes are readily attracted to a wide range of small native and introduced flowers.

Wingspans for the pictured adult specimens are: males 37mm and females 38mm.

An unusually marked female from near Musgrave, Cape York Peninsula North Queensland.

Ovipositing females flutter slowly around the host plants and settle, laying the eggs singly, chiefly on the upperside of fresh young leaves and shoots. The wings remain closed while ovipositing occurs. The small-leafed, low-growing Scrambling Caper (Capparis sarmentosa) is commonly used as a host plant in Southeast Queensland. C. arborea, C. canescens and C. velutina are also recorded as host plants for this species (Moss, 2010). Females will oviposit within centimetres of ground level if suitable fresh leaves are available.

In December 2006, an egg was collected and raised through to an adult on C. sarmentosa. This egg was barrel shaped, approximately 0.6 mm wide x 1.0 mm high, with 13 vertical ribs and very fine horizontal lines between them. It was pale white when laid then later developed irregular pink markings.

The larva consumed the eggshell soon after hatching. It rested along the fine stems of the host plant and fed from the edges of soft, fresh leaves during daylight hours. The final instar larva was also observed feeding during the night. Similar to other species in the Elodina genus, the beautifully coloured larvae are very cryptic and can be difficult to

locate on the host plant. This larva attained a length of 22mm and I could only identify four instars as pictured (similar to E. angulipennis, see W. Jenkinson, 2010).

Elodina parthia (Striated Pearl-white) Images left to right: male, female, male underside, female underside

Several day old egg

In captivity the pupa, measuring 14mm in length, was located below a stem of the host plant. It was attached with silk by the cremaster and a central girdle (similarly described by W. Rainbow, 1907).

Larval duration was 15 days while pupal duration was 9 days.

Within the new boundary of the Scenic Rim Regional Shire south of Brisbane, I have records of adults from July through to March. The adults appear to be more numerous during spring, late summer and early autumn. However, this may relate to the timing of local rainfall triggering fresh growth of the host plants. Photos Wesley Jenkinson References Braby, M.F. 2000. Butterflies of Australia – Their Identification, Biology and Distribution. vol 1. CSIRO Publishing, Melbourne. Jenkinson, W. 2010. Life history notes on the Southern Pearl-white, Elodina angulipennis (P.H. Lucas, 1852) Lepidoptera: Pieridae. Metamorphosis Australia: Magazine of the Butterfly & Other Invertebrates Club 59: 13-16. Moss, J.T. 2010. Butterfly Host Plants of south-east Queensland and northern New South Wales. 3rd edition, BOIC. This article appeared in Issue Number 62 of “Metamorphosis Australia” in September 2011.

1st instar larva 2nd instar larva

3rd instar larva 4th instar larva

Pre pupa Pupa