Tuatara: Volume 9, Issue 2, November 1961
New Zealand Butterflies
New Zealand Butterflies
Although poorly represented in New Zealand, butterflies are familiar to any person with an interest in the outdoors, mainly on account of their bright colours and diurnal habits. Most people are aware that the order Lepidoptera contains the butterflies (Rhopalocera) and moths (Heterocera), but they do not realise that these two divisions are not of equal systematic value. There is no scientific justification for ranking the butterflies any higher than superfamilies and in recent classifications of Lepidoptera (Imms. 1957) three suborders are recognised, based primarily on the female genital system. The butterflies comprise two of the thirteen super-families belonging to the largest suborder, the Ditrysia. Of these two superfamilies, namely the Papilionoidea and the Hesperioidea, only the former is represented in New Zealand.
Both superfamilies of butterflies may be distinguished from all other Lepidoptera, firstly by the antennae, which are slender and dilated distally to form a club-like ending, and secondly by the absence of any wing-coupling bristles (frenulum) which occur in all moths, the wings being held together by means of an enlarged humeral lobe at the base of the hindwing. Clubbed antennae are very rare in other Lepidoptera, and when they do occur the frenulum is always present, so these two features considered together are completely diagnostic of butterflies and moths. Most butterflies are brilliantly coloured on their upper surface and protectively coloured beneath and rest with their wings held vertically.
The vast majority of butterflies are diurnal and usually fly only in sunshine. They occur in all habitats in New Zealand from coastal dunes and lowland forests or scrubland, to high alpine slopes, but are seldom very abundant. The flight pattern of different species varies considerably, that of the smaller ones generally being rather weak, erratic and close to the ground, while the larger ones tend to have a soaring flight, often rising to considerable heights.
The mouthparts of butterflies, in common with most moths, are highly modified from the fundamental biting type in many insects. The mandibles are lost and the maxillae form a long, hollow, suctorial proboscis which is normally coiled up under the head like a watchspring. When feeding it is uncoiled and inserted into flowers to probe for honey. The maxillary palpi are degenerate but the labial palpi are moderately long with a pointed terminal segment and page 66 are referred to simply as ‘the palpi’. They function as sensory organs and may be held close together as in Argyrophenga antipodum and other Satyrinae, or divergent as in the Nymphalinae.
The legs, when fully developed, consist of nine segments jointed to one another, but a peculiarity of two families of butterflies is that the forelegs may be considerably reduced so as to be quite useless for walking, a feature which is used in classification.
The wings, as in all winged insects, are supported by a number of thickened veins or nervures. The distribution of these is reasonably constant within the different groups and may be used for classification. Basically the neuration of each wing consists of a basal ‘cell’ from which a number of nervures are given off radially. The cell may be ‘open’ distally as in the Nymphalinae, due to the complete or partial break-down of a short cross-nervure. The wings and body of butterflies and moths are clothed with flat scales arranged in overlapping rows. These scales are not necessary for flight. They have apparently evolved primarily for colouration. Some male butterflies possess specialised scent-scales or androconia in patches on their wings as on the hindwing of the ‘Monarch’ Danais plexippus.
Butterfly eggs are of various form, the general shape and pattern of ridges on the shell usually being characteristic of each family or subfamily. The shell may be consumed by the young larva immediately after hatching.
The caterpillar, or larva, is divided into thirteen segments and a well-defined head. The first three segments, or thoracic segments, are each furnished with a pair of three-jointed legs, terminating in a single claw. The remaining ten segments form the abdomen and the third to sixth of these each bear a pair of broad unjointed prolegs equipped with many minute hooklets. A pair of anal claspers, similar to the prolegs, occurs on the thirteenth segment. There is much diversity, both in shape and hairy covering, between the different groups of butterfly larvae. The larval phase varies in length from about four weeks to two or three months in some cases.
Growth is by a series of moults (ecdyses), the final ecdysis producing a chrysalis (pupa), which possesses all the structures of the adult butterfly is a resting stage. Three types of pupa are seen in our butterflies. (1) The most advanced type are those suspended upside down by a short hooked stem (cremaster) on the terminal segment as in the Danainae, most Satyrinae, and Nymphalinae. (2) Some are attached by the cremaster but are supported head-upwards by a silken girth as Pieris rapae. (3) Others are free on the ground, amongst dead leaves or beneath stones as in the New Zealand Lycaenidae and a few Satyrinae.
Pupation in hanging pupae is an interesting process. A small silk pad is first spun by the larva which then hangs head-downwards from the pad by its anal claspers for two to three days. The larval skin page 67 bursts behind the head and is pushed to the tail end where it is discarded and the cremaster attached by the following rather dangerous manoeuvre. The pupa grips the larval skin between the last two segments on the underside and then the tip of the body pierces the skin above the point where it is held and entangles its cremaster in the silken pad. The grip on the skin is then relaxed so that the skin shrivels and falls.
The pupal state lasts for about three weeks. Towards the end of this period the colours of the adult butterfly are usually visible through the thin pupal walls. At the emergence of the adult (imago) the pupal case splits behind the head and the butterfly draws itself out with its fully-developed legs. The wings are very small and soft and are allowed to hang down while blood is forced in to expand them. The process takes about two hours. During expansion of the wings a large drop of thick reddish liquid, the meconium, is exuded from the anus. This is the stored up excretory products from the pupa, which has no functional mouth or anus.
Butterflies are well equipped with sense organs. The large pair of compound eyes, although short-sighted and said to be only capable of recognising their own species at distances of about three feet, are very effective for detecting small movements. Eltringham (1923) has shown that butterflies possess colour vision, but that the range of colours perceived varies in different species. They cannot fly or control their movements if the compound eyes are coated with black dye. Taste-organs are present on the feet of the posterior legs in some butterflies, particularly the Nymphalinae, where they are extremely sensitive to sugar solutions. The sense of smell is located in the antennae. It has been shown that the male relies on sight for detecting the female but that the sexual act is stimulated by scent.
Butterflies exhibit perhaps the most striking range of colours in the animal kingdom. These colours provide a means by which the males recognise the females and also serve as their chief means of protection. The colours may be structural, or due to pigments in the scales. Structural colours, such as the metallic blue in the male of Hypolimnas bolina, are produced either by interference, caused by many very fine layers in the scales, or by diffraction if the surface of the scale is covered with microscopic ridges. Pigment colours may be of two types, those manufactured by the animal, and those derived from its food. Pigments manufactured by the butterfly include the yellow and white colours of the Pieridae which are uric acid derivatives built up from the excretory products, and the brown and black menanin pigments which occur in almost all butterflies. Flavones, ivory or yellow pigments, are colours of the second type, obtained directly from the larval foodplants and it has been said that the red pigments in Vanessa butterflies are built up from chlorophyll absorbed during larval life, although this is still uncertain.page 68
A number of insect parasites attack butterfly larvae and pupae. Of the New Zealand species, Dodonidia helmsi is probably the most unfortunate, as it is very susceptible to heavy attacks from a small Tachinid (Diptera) larval parasite. The larvae are killed at maturity and the oval brown puparia of the fly can be seen surrounding the dead larva. The Vanessa butterflies may be parasitised by an Ichneumon (Hymenoptera), Echthromorpha intricatoria, which destroys the pupae. Larvae and pupae of Chrysophanus boldenarum have been found closely associated with ant nests but suffer no harm from them. Many foreign species of Lycaenidae exhibit strange relationships with ants. In some species the larvae possess a gland on the seventh abdominal segment which secretes droplets of a sweet fluid, very attractive to ants. The ants caress them and crawl over them, offering a powerful deterrent to normal insect parasites. Some species of Lycaenidae have grown completely dependent on the ants, and the larva of the British Large Blue Maculinea arion is actually carried into the ant nest and devours young ant grubs. The dependence of our Lycaenid larvae on ants has not been fully investigated.
Butterflies may pass the winter either as small larvae or as adult insects. The species which hibernate in the imago state, namely Vanessa gonerilla, V. itea and Chrysophanus salustius, may occasionally be met with on warm days in the middle of winter. However, the majority of butterflies pass the winter in the larval stage and are thus never met with during this time.
Only seventeen species of butterflies have been recorded from New Zealand, four of which are very rare migrants, one, Danais melissa hamata, being represented by only a single specimen. This is a very small number when one considers the area and climate of New Zealand and is in contrast to the large moth fauna. Eight species of butterflies are endemic, three of which are confined to the South Island. Of the remaining nine species known to occur elsewhere, eight are from Australia and the other, Pieris rapae, was accidentally introduced by man as late as 1930. The widespread Danais plexippus and Vanessa cardui, and the Australian species V. itea and Lycaena labradus are firmly established in New Zealand, while Danais chrysippus, D. melissa hamata, Hypolimnas bolina and Precis villida are occasional migrants from Australia which have never been observed breeding in New Zealand. Our most interesting butterflies are probably the Satyrinae; the three South Island species, Erebia merula, E. butleri, and Argyrophenga antipodum have no affinities with Australia or the Malay Peninsula but apparently are related to species in South America. Tillyard (1926) considers that these species have arrived from the south, hence their South Island distribution. Our other Satyrinae, Dodonidia helmsi, he considers to be closest to the Australian genus Oreixenica. The New Zealand page 69 species of ‘Coppers’, genus Chrysophanus, are evidently closest to Holarctic species of the same genus, one which is absent from Australia.
In the key to adult butterflies which follows, the divisions are arranged in what is generally accepted as their natural order, beginning with the most specialised. Diagnoses of subfamilies and higher categories are based on structural characters, all of which may be detected with the aid of a hand lens only, while specific determination relies on colour pattern. Actually in most cases identification should be possible from an inspection of the figures and later checked against the key. Total wingspan with wings outspread is given as W. Structural figures are all magnified, but those of the wing patterns are approximately natural size and all to scale. To use the key, follow the numbered paragraphs consecutively as long as the specimen agrees; if a character differs go directly to the number in brackets. It is extremely unlikely that any further species of indigenous butterflies will be discovered but it is quite possible that other Australian species may appear in this country.
It had been hoped to include the eggs, larvae and pupae of our butterflies in this article but published descriptions of these are insufficient to enable a complete key to be compiled so this will follow in the near future as a second part to the present article.
The following is a brief diagnosis of the two superfamilies of butterflies:
The neuration of the forewing shows at least two nervures stalked (i.e. fused together to give a branched appearance as in Fig. 3), and the antennae are close together at their bases. All the New Zealand species belong to this group.
In the forewings all the nervures arise separately from the cell, the antennae are wide apart at their bases and are usually hooked at their tip. These are known as ‘Skipper’ butterflies, so named because of their rapid darting flight. Ninety-two species are found in Australia but none have been recorded from New Zealand.
Key to the Papilionoidea
|1 (26)||Anterior pair of legs imperfect, or functionally perfect but distinctly shorter than the remaining two pairs.|
|2 (25)||Anterior pair of legs imperfect in both sexes, less than half the length of the other pairs, so that insect stands on only two pairs as in Fig. 10.||Fam. Nymphalidae|
|(The dominant family of butterflies.)||page 70|
|3 (16)||Discal cell of hindwing closed by a complete nervure (Fig. 3).|
|4 (9)||Antennal club elongate and very gradually thickened (Fig. 1).||Subfam. Danainae genus Danais|
|5 (6)||Wing nervures inconspicuous; uppersurface pale brown with dark brown margins to both wings; several white patches across apex of forewing and a row of small white spots against the outer margin of both wings; W. 2 ⅓-3 (Fig. 5).||D. chrysippus L.|
|(A rare migrant to New Zealand which occurs naturally in Australia, Africa, Western Asia, the East Indies and Greece.)|
|6 (5)||Wing nervures conspicuous: narrowly or broadly marked in black.|
|7 (8)||Large rich orange areas on uppersurface between nervures; nervures narrowly marked in black and with broad black margins to both wings; the margins containing a double row of whitish spots; W. 3 3/4-4 ½ inches (Fig. 6).||D. plexippus L.|
|(Formerly a migrant to New Zealand, this species, the ‘Monarch’ butterfly, now breeds here and is quite common in the north of the North Island extending south to the Nelson Province. It appears from January until May.)|
|8 (7)||Small pale blue streaks and spots on the uppersurface between nervures; nervures broadly marked in black so that black is the dominant colour; W. 3 inches.||D. melissa hamata W.S.M.|
|(A single specimen of this Australian species was taken on Kapiti Island in 1940)|
|9 (4)||Antennal club broad and distinct from the remainder of the antenna as in Fig. 2.||Subfam. Satyrinae|
|(Easily distinguished by the nervures of the forewings being swollen or bladder-like at the base of the wing as in Fig. 3. The four New Zealand species are endemic, three of which are confined to the South Island.)|
Fig. 1: Elongate antennal club of Danais plexippus. Fig. 2: Broad antennal club of Erebia merula. Fig. 3: Neuration of fore and hind wings of Argyrophenga antipodum, showing ‘closed’ cell. Fig. 4: Neuration of hindwing of Vanessa itea, showing ‘open’ cell partially closed by an imperfect nervure. Fig. 5: Danais chrysippus. Fig. 6: Danais plexippus. Fig. 7: Argyrophenga antipodum. Fig. 8: Erebia merula. Fig. 9: Erebia butleri. Fig. 10: Erebia butleri, underside. Fig. 11: Dodonidia helmsi
|10 (13)||Uppersurface of both wings almost entirely one colour. apart from some small black rings with white centres.||genus Erebia|
|(Two species of this large genus occur in the South Island mountains, but there are no species of Erebia in Australia.)|
|11 (12)||Underside of hindwings black or greyish, sometimes with some paler shading; uppersurface bronzy-black with 3-5 jet-black rings with white centres situated near the apex of the forewing; some specimens show an indistinct brownish area across the apex of the forewing: W. 1 3/4-2 inches (Fig. 5).||E. merula Hew. (= pluto Fered.)|
|(Frequents shingle slopes at elevations of 4-6,000 feet on mountains from Nelson southwards and may often be quite common. It appears from September until March. Preliminary studies on this species indicate that it is incorrectly placed in the genus Erebia but further research is necessary to clarify its position.)|
|12 (11)||Underside of hindwings brown with several very prominent white streaks: uppersurface rich brown with a reddish brown apical patch on the forewing containing a black spot with 1-2 white centres; W. H inches (Figs. 9 and 10).||E. butleri Fered.|
|(Occurs in numbers in a few restricted areas of the South Island mountains at elevations of about 4,000 feet in tussock country. It has been taken from January until March.)|
|13 (10)||Uppersurface of both wings dark brown with broad orange or yellowish markings and several white-centred black rings.|
|14 (15)||Hindwings rounded, their underside dull yellow with seven long silver streaks between the nervures; W. 1 ½-1 7/8 inches (Fig. 7 wing pattern and Fig. 3 neuration).||genus Argyrophenga, A. antipodum Dbld.|
|(The colour varies considerably according to locality but the female is always paler than the male and much scarcer. Very common on tussock lands in the South Island, appearing from November to March. Flight rather weak.)|
|15 (14)||Hindwings produced posteriorly into a short thick tail, their underside silvery-white with five reddish-brown stripes; W. 2-2 ⅜ inches (Fig. 11).||genus Dodonidia, D. helmsi, Fered.|
|(Occurs in clearings in beech forest of both islands, often at considerable altitudes. Flight is reasonably strong, often alighting high on trees. Appears in January and February but is never very common.)||page 73|
|16 (3)||Discal cell of hindwing open, or partially closed by an imperfect nervure as in Fig. 4.||Subfam. Nymphalinae|
|(Only one of the five species occurring in New Zealand is endemic, the others being shared with Australia.)|
|17 (18)||Very large species, total wingspan over 3 ½ inches; upper- surface of wings black, forewings of male with a large white blotch in the middle surrounded by a patch of iridescent blue, female with an orange patch near the posterior margin of the forewings and some smaller white spots; W. male 3 ½ inches, female 4 inches (Fig. 12).||genus Hypolimnas, H. bolina Fabr.|
|(Known as the ‘Blue Moon’ butterfly, this species is an occasional immigrant from Australia, appearing from January to May. It is a widespread species occurring throughout Australia, Polynesia and the Oriental region.)|
|18 (17)||Moderate sized species, total wingspan less than 3 inches.|
|19 (24)||Forewings with a broad dark grey or black apex, the black area containing several small white patches, hindwings with four black rings with blue centres.||genus Vanessa|
|20 (21)||Upperside orange-red with some irregular dark coloured markings; W. 2-2 3/4 inches (Fig. 15).||V. cardui L.|
|(Occurs throughout New Zealand but is never common. It appears from December to April, but hibernating specimens may be seen during winter and spring. Flight rapid and owing to its extreme timidity it is difficult to capture. Known as the ‘Painted Lady’ this species is probably the widest distributed of all the Lepidoptera. occurring throughout the world. In those specimens from the Northern Hemisphere, the four black spots on the hindwings have no blue centres.)|
|21 (20)||Upperside of forewing with a broad oblique red or yellow band across the middle.|
|22 (23)||Forewings with an oblique yellow band across the middle. reddish-brown towards the base; W. 2 ¼-2 ½ inches (Fig. 16).||V. itea Fabr.|
|(Occurs throughout the North Island and as far south as Christchurch. Appears from November to April with hibernating specimens appearing in early spring. Flight rapid, often rising to considerable heights above the ground. Beyond New Zealand this species, known as the ‘Yellow Admiral’, occurs in Australia, Tasmania and the Loyalty Islands.)|
|23 (22)||Forewings with an oblique, slightly wavy, red band across the middle, very dark brown towards the base; W. 2 ⅜-2 3/4 inches (Fig. 14).||V. gonerilla Fabr.page 74|
|(Known as the ‘Red Admiral’, this endemic species is very common throughout New Zealand and the Chatham Islands. Its flight and times of appearance are similar to V. itea and it is often seen in forest clearings and on mountain tops.)|
|24 (19)||Forewings without dark coloured apex; both wings dull brown with bronzy reflections; markings orange; hindwings with one large and one small blue-centred, black rings; W. 2 inches (Fig. 13).||genus Precis, P. villida Fabr.|
|(An occasional migrant to New Zealand from Australia. some years occurring quite commonly. Flight and general appearance rather similar to V. cardui. It has appeared in New Zealand from December to February, and is abundant throughout Australia.)|
|25 (2)||Anterior pair of legs imperfect and brush-like in the male, functionally perfect but distinctly smaller than the remaining pairs in the female.||Fam. Riodinidae|
|(An extensive family of small butterflies characteristic of the Neotropical region but absent from Australia and New Zealand.)|
|26 (1)||Anterior pair of legs fully developed so that the insect stands on all three pairs as in Fig. 19.|
|27 (34)||Anterior feet of male with claws reduced, either one or both claws being absent (Fig. 23).||Fam. Lycaenidae|
|(Small butterflies, the New Zealand species with wing-spans of less than 1 ½ inches. We have four species, three of which are endemic.)|
|28 (29)||Uppersurface of both wings without distinct dark coloured or black markings; wings dull pale blue, bordered with brown; W. 1 inch (Fig. 18).||genus Lycaena, L. labradus Godt.|
|(The common blue butterfly, abundant in hot, dry, open country, but rare in Southland. Occurs from October to April, and is widely distributed throughout Australia and the South Pacific.)|
|29 (28)||Uppersurface of both wings with distinct black or very dark coloured markings.||genus Chrysophanus|
|30 (33)||Uppersurface of wings shining coppery with several dark transverse bands and spots.|
Fig. 12: Hypolimnas bolina. Fig. 13: Precis villida. Fig. 14: Vanessa gonerilla. Fig. 15: Vanessa cardui. Fig. 16: Vanessa itea. Fig. 17: Chrysophanus salustius. Fig. 18: Lycaena labradus. Fig. 19: Chrysophanus enysii. Fig. 20: Chrysophanus enysii, underside. Fig. 21: Pieris rapae. Fig. 22: Claws of Pieris rapae. Fig. 23: Anterior claw of male Chrysophanus boldenarum. Fig. 24: Chrysophanus boldenarum, male.
|31 (32)||Underside of hindwings pale yellow with very pale spots; W. 1 1/8-1 ½ inches (Fig. 17).||C. salustius Fabr.|
|(In some specimens the underside of the hindwings is a uniform pale brown. The extent of the black markings on the upperside varies greatly, some forms approaching close to the following species. A series of blue subterminal spots often occurs on both wings in coastal and mountain forms. Common throughout New Zealand in open sunny places. Appears from November to April.)|
|32 (31)||Underside of hindwings yellow with a large patch of purplish-brown around the margin and across the middle; upperside pale coppery with very broad black bands; W. 1 1/8-1 ⅜ inches (Figs. 19 and 20).||C. enysii Butl.|
|(Not nearly as common as C. salustius but has occurred at restricted places throughout New Zealand. Usually found in clearings amongst scrubby forest where it appears from December to February.)|
|33 (30)||Uppersurface of wings yellowish-brown (female) or iridescent purple (male) with dark coloured or black spots and bands; underside of hindwings slatey-grey; W. 7/8 inch (Fig. 24).||C. boldenarum White|
|(Very common on stony places throughout the South Island and has occurred in some restricted localities in the North Island. It appears from November to March.)|
|34 (27)||Anterior feet of male with claws fully developed (i.e. two distinct curved claws on each foot).|
|35 (36)||Inner margin of hindwing (i.e. that nearest the abdomen) modified and upturned.||Fam. Papilionidae|
|(Mainly tropical butterflies, large and brilliantly coloured with wings of variable shape, the majority of species having long tail-like projections (‘Swallowtails’). Seventeen species occur in Australia but none have been recorded from New Zealand.)|
|36 (35)||Inner margin of hindwing not modified or upturned.||Fam. Pieridae|
|(A world-wide family including the ‘White Butterflies’, characterised by the feet having bifid claws (Fig. 22). One species was accidentally introduced into New Zealand in 1930 and is now one of our commonest butterflies.)|
|Wings entirely creamy-white with a black apex to the forewings and several black spots; W. 1 ½-2 ¼ inches (Fig. 21).||genus Pieris, P. rapae L.|
|(Known as the ‘Small White’, this species appears from August until May and its range extends throughout Asia. Europe and North America.)|