[Read before the Otago Institute, 8th December, 1925; received by Editor. 31st December, 1925; issued separately, 15th November, 1926.]
In a paper on “The Fertilization of New Zealand Flowering Plants” read before the Otago Institute in May, 1880, I stated that very little was known as to the relation of birds and insects to flowers in this country. Up to that time only a few scattered references to the subject were available. My own contribution (34) added a little to the sum of knowledge, and since then a few more data have been obtained. But even to-day the amount of information is very fragmentary. Botanists, as a rule, do not trouble themselves with the insects that visit the flowers which they collect; and entomologists are seeking the insects themselves, and seldom notice the flowers they are found on. Yet the subject is one of great interest to the naturalist, as it displays in a marked degree the principle of adaptation in nature. I do not propose to go into the general question in this paper, my object is only to summarize what has been done in New Zealand in the hope that further observations may be made and published.
Pollination of flowers by birds is practically unknown in Britain, and, as far as I know, in Europe. It is found to occur only among certain families of birds, and of these three occur in this country.
Meliphagidae or Honey-eaters.
1. White-eye; wax-eye; blight-bird; twinkie;—Zosterops coerulescens.
These little birds probably visit many kinds of flowers, but have only been definitely recorded by Kirk (21) as seen taking nectar from Fuchsia excorticata. Petrie (26) thinks that Vitex lucens is visited by small birds, probably of this species.
2. Tui — Prosthemadera novae-zealandiae.
3. Bell-bird — Anthornis melanura.
Both these species regularly visit the flowers of New Zealand Flax (Phormium tenax), Rewa-rewa or Native Honeysuckle (Knightia excelsa), Kowhai (Sophora tetraptera), Clianthus puniceus, various species of Ratas (Metrosideros), and Fuchsia excorticata. Scarlet Mistletoe (Elytranthe Colensoi), Rhabdothamnus Solandri and Dracophyllum longifolium are occasionally visited by birds, and most probably by these two species.
4. Stitch-bird — Pogonornis cincta.
This species is now apparently extinct on the main islands of New Zealand, but survives on the Little Barrier, and perhaps on one or two of the smaller outlying islands of the north. Reischek (19) who observed it on the Little Barrier, says “it feeds on small insects and sucks the honey from the native wild flowers and trees.”
5. Kaka — Nestor meridionalis.
This bird visits Phormium when in flower, and no doubt many other plants. Hutton (19) states that “the Kaka sips the honey from the flowers, and this, as well as insects, constitutes part of its diet. In September it has been seen in Canterbury poised on the slender bough of a tall Panax, luxuriating on the viscid nectar of its blossoms.” Cheeseman (8) reports it on flowers of Clianthus puniceus.
6. Red-fronted Parakeet — Cyanorhamphus novae-zealandiae.
7. Yellow-fronted Parakeet—C. auriceps.
These birds have only been recorded on the flowers of Phormium. But in early and especially pre-settlement days, when they were extraordinarily abundant, they must have visited and pollinated many species of nectar-producing flowers.
Of insects practically only four orders in New Zealand are flower-visitants, viz. Hymenoptera, Lepidoptera, Coleoptera and Diptera. A very few hemipterous insects are occasionally found on flowers.
The Hymenoptera are poorly represented in New Zealand, and only a few have been observed on native flowers. I have noted a small black bee on Veronica Traversii and V. glaucocoerulea, and others on other species, but none of these have been identified. Lamprocolletes fulvescens a very common native bee, which burrows in dry banks, and lays its eggs in small balls of bee-bread made from pollen, is very common, and may be seen on many introduced garden flowers, but I have never observed it on native flowers, though it must formerly have obtained the pollen which it seeks from them alone.
Great numbers of Lepidoptera are flower visitants, and many flowers appear to be specially adapted for pollination by moths, e.g. species of Leucopogon, Cyathodes, and similar flowers with hair-lined tubes. Only insects with relatively long and slender proboscides could reach the nectar in such flowers, but I have not a single record of moths being taken on such blossoms. The following species of Lepidoptera have been observed or captured on the flowers named:—
Nyctemera annulata on Veronica Traversii.
Orthosia comma Walk. on Metrosideros scandens, and sp. of Veronica.
Orthosia immunis Walk. on Metrosideros scandens, and sp. of Veronica.
Leucania griseipennis Feld. on Veronica sp.
L. purdii Fered. on Gaya Lyallii.
L. atristriga Walk. on Metrosideros scandens.
L. alopa Meyr. on Veronica sp.
Melanchra maya Huds. on Veronica sp.
M. mutans Walk. on Gaya Lyallii.
M. pelistis Meyr. on Metrosideros scandens and Veronica sp.
M. diatmeta Meyr. on Parsonsia sp.
M. rubescens Butl. on Gaya Lyallii.
Erana graminosa Walk. on Metrosideros scandens.
Tatosoma agrionata Walk. on Rubus australis.
T. timora Meyr. on Rubus australis.
Xanthorhoe perfectata Walk. on Veronica sp.
X. beata Butl. on Metrosideros scandens.
X. umbrosa Philp. on Dracophyllum longifolium.
Epirrhanthis alectoraria Walk. on Metrosideros scandens.
Selidosema productata Walk. on Metrosideros scandens.
S. aristarcha Meyr. on Metrosideros scandens.
S. panagrata Walk. on Metrosideros scandens.
Chalastra pelurgata Walk. on Metrosideros scandens.
Gonophylla nelsonaria Feld. on Metrosideros scandens.
Azelina gallaria Walk. on Metrosideros scandens.
A. ophiopa Meyr. on Metrosideros scandens.
Ipana leptomera Walk. on Metrosideros scandens.
Declana floccosa Walk. on Gaya Lyallii.
Vanessa gonerilla Fabr. on Metrosideros scandens.
V. itea Fabr. on Veronica salicifolia.
Dodonidia helmsi Fereday on Veronica sp.
Chrysophanus boldenarum White on Donatia novae-zealandiae.
I believe the Diptera are the most numerous flower-visitants among New Zealand insects. I expressed the opinion in 1880 (34) that the insects of this order “depend chiefly on scent in their search for food, and certainly this would explain the fact of their being the sole fertilizers of many inconspicuous or green flowers, as Tupeia antarctica and various species of Pterostylis.” Subsequent observation has only strengthened that opinion. Yet very few species of Diptera have been identified as flower-visitants. Only the following have been recorded:—
Arocera longirostris on Metrosideros scandens.
Helophilus cingulatus on Metrosideros scandens.
H. hochstetteri on Veronica sp.
Syrphus novae-zealandiae on Veronica sp. and Rubus australis.
Exechia Thomsoni. Miller (Fam. Mycetophylidae) on Corysanthes oblonga.
But the following flowers are probably more or less dependent on Diptera for their pollination:—
Cordyline sp., Astelia sp., Caleana minor, all species of Pterostylis, Acianthus Sinclairii, Cyrtostylis oblonga, all species of Corysanthes, Loranthus micranthus, Tupeia antarctica (midge-like Diptera), Dactylanthus Taylori, Claytonia australasica, Clematis sp., Melicope simplex, Metrosideros scandens, M. hypericifolia and other species, Nothopanax Colensoi, Schefflera digitata, most of the fragrant flat-flowered hermaphrodite and dioecious Umbelliferae, Mentha Cunninghamii,
Glossostigma sp., Utricularia sp., most species of Veronica, Selliera radicans, and numerous Composites. I believe that many other species are visited by native flies, but have no direct evidence on the subject.
Of Coleoptera the following species have been recorded:—
Pyronota festiva Fabr. on Leptospermum sp.
Rygmodus modestus White, on Brachyglottis repanda.
Dasytes cinereohirtus Broun, on Rubus australis and Aristotelia racemosa.
D. Cheesemani Broun, on Myoporum laetum and Wahlenbergia gracilis.
Cryptophagus castaneus—?—on Rubus australis and Aristotelia racemosa.
Selenopalpus cyaneus Fabr. on Cordyline australis.
Mordella antarctica White, on Leptospermum sp.
Zorion minutum Fabr. on Rubus australis.
Navomorpha sulcatus Fabr. on Rubus australis.
Arnomus Brouni Sharp, on Leptospermum sp.
Tigones caudata Broun, on Pittosporum tenuifolium.
Erirhinus limbatus Pascoe, on Pittosporum tenuifolium.
Eugnomus, all species. (The Index Faunae Novae-Zealandiae gives 22 species) on Rubus australis.
Hoplocneme Hookeri White, on Rubus australis.
Apion metrosideros Broun, on Metrosideros tomentosa.
Oropterus coniger White, on Fuchsia excorticata.
Colaspis—11 species, on many shrubs.
Empaeotes censorius—?—on Rubus australis.
One species (undetermined) belonging to the Staphylinidae on Selliera radicans.
Various undertermined species on Aciphylla squarrosa and A. Colensoi.
Two undetermined species on Muehlenbeckia adpressa.
These only represent a small proportion of the flower-visiting beetles.
Since settlement commenced in New Zealand, the destruction of forest by felling and burning, the clearing off of the surface growth of vast areas of native grass, fern and flax land must have destroyed
an enormous amount of insect life. Added to this, the introduction of numbers of foreign birds and insects, as well as of foreign plants, has profoundly modified the original conditions. Many of the indigenous flowering plants are now visited and pollinated by introduced insects, especially bees and flies of various species, and this complicates the task of finding out the native insects which formerly pollinated the native flowers. This has to be borne in mind when studying this question. The number of insects which have been recorded is seen to be very few, though there is no doubt that great numbers of native flowers are dependent on insects for pollination.
Looking at the question now from the botanical point of view the following flowering plants have been recorded either as being visited by insects, or as having flowers attractive to insects by fragrance or nectar, or both.
1. Cordyline Banksii Hook. f. visited by the beetle Rygmodus modestus (32).
2. Cordyline australis Hook. f.
The flowers are very sweet scented, and attract numerous Diptera. I have also collected on it numerous beetles of one species—Selenopalpus cyaneus.
3. Astelia nervosa Banks and Solander.
Visited by numerous Diptera (32). Kirk (16) says—“All the large kinds (of Astelia) are sought after when in flower by bees.” Presumably he means introduced honey bees.
4. Phormium tenax Forst.
In my note-book I record in 1879 that “the flowers contain immense quantities of honey and are fertilised by honey-birds, tuis, etc.” Later on (34) I record them as visited by birds.
5. Libertia ixioides Spreng.
The flowers secrete abundance of nectar. On opening, the anthers and the style-branches diverge in different directions, and only the extremities of the latter are stigmatiferous.
6. Dendrobium Cunninghamii Lindl.
The flowers secrete a considerable quantity of nectar and appear quite incapable of self-pollination.
In 1878, out of 22 flowers examined by me, 5 had their pollinia removed. In January 1880 I found the plant flowering in gorgeous profusion in Stewart Island, and examined 80 flowers, but only found 10 with the pollinia removed. I saw no insects actually at work.
7. Earina mucronata Lindl.
Flowers very fragrant and producing a considerable quantity of nectar.
8. Earina autumnalis Hook. f.
The flowers are fragrant and secrete nectar. They appear to be quite incapable of self-pollination, but I have never seen nor taken insects on them. Out of 91 flowers examined, 41 had the pollinia removed. In 1878 I pollinated six flowers with their own pollinia, and
also cross-pollinated sixteen with pollinia taken from other flowers on the same bunch, but in neither case were they fertilized.
9. Sarcochilus adversus Hook. f.
This little species produces minute inconspicuous flowers, which are slightly fragrant and produce a relatively large amount of nectar. They appear (34) to me quite incapable of self-pollination, owing to a mechanical depression and separation of the pollinia when removed from the anther.
10. Thelymitra longifolia Forst.
This is a very variable species, some forms bearing conspicuous blue or even white flowers, while others which are nearly always white or pinkish scarcely open their blossoms at all. In my paper on the fertilization of Orchids (33) I stated that the species was probably self-fertilized. Cheeseman (3 and 7) considers them nearly always self-fertilized, and Fitzgerald says the same of the Australian forms of the species. When, however; I was in Stewart Island in January 1880, I found many lilac- and pink-flowered specimens, which were very conspicuous, and in many of them the pollinia had been removed, showing that insects had visited them.
11. Microtis unifolia Reichenbach.
The flowers are green and inconspicuous. I could detect neither nectar nor fragrance, yet in one fine spike examined by me (33) I found that 31 flowers out of 32 had the pollinia removed, the top flower being just opened. In the majority of cases, however, and I have examined hundreds of flowers, the pollinia were glued to the upper edge of the stigma, and in many cases the pollen tubes could be detected, showing that self-pollination had taken place.
12. Prasophyllum Colensoi Hook. f.
Though the flowers are sweet-scented, and are occasionally visited by insects, they are mostly self-pollinated, as in a majority of those examined the pollen grains were found to be adhering to the stigma. Of 75 flowers examined only 4 had the pollinia removed.
13. Caleana minor R. Br.
Cheeseman (9) states “that it seems probable that small Diptera or other minute insects alight on the labellum, which then capsizes, imprisoning the insects in the concavity of the column; that they then disturb the pollinia, and either fertilize the flower with its own pollen, or when escaping convey the pollinia to other flowers. The latter supposition appears to me the most likely; but Mr. Fitzgerald, who had good opportunities of studying the fertilization of the plant in Australia, considers that it is almost invariably self-fertilized.”
Kirk (20) describes the same species, and quotes from Fitzgerald's “Australian Orchids” as to its method of fertilization. He tried to produce pollination by experimenting with blowflies, houseflies and ladybirds, but was unsuccessful in every case. I think his chosen insects were too large. In most small orchids upon which I have seen flies, they were small species of Culicidae.
14. Pterostylis Banksii R. Br.
The flowers of all the species of Pterostylis examined by me (33) appear to be incapable of self-pollination, but out of 39 flowers of this
species looked into, only one had the pollinia removed. Cheeseman (3) considered that “the insect which fertilizes this species is nearly twice the size of that which performs the same office for P. trullifolia.”
I pollinated a number of flowers of this species with their own pollinia, but the results were inconclusive, as the plants were in the open, and I was not able to follow the experiment satisfactorily.
15. Pterostylis australis Hook. f.
I examined 22 specimens of this species, and found that all had their pollinia intact. The flowers may be self-fertilized, though I think it very improbable. The impression in my mind is that the insects which formerly pollinated it are become very rare.
16. Pterostylis graminea Hook. f.
The same remarks apply to this species as to P. Banksii. Of those examined, the number of which I have unfortunately lost, none had the pollinia removed.
17. Pterostylis trullifolia Hook. f.
In this species the flowers are fragrant. The labellum is extremely sensitive, springing up at once when touched; only very small insects could enter the flowers, which are only about ¼-inch long. Of 14 flowers examined by me, 5 had their pollinia removed, while the other 9 were newly opened and probably had not had time to be visited by insects.
18. Acianthus Sinclairii Hook. f.
Cheeseman (4) states that numerous Diptera were seen on a bed of Acianthus flitting from flower to flower. Out of 134 flowers examined by him 115 matured their capsules.
19. Cyrtostylis oblonga Hook. f.
Cheeseman (4) records that “notwithstanding the minuteness of the flowers they are frequently visited by insects, chiefly minute species of Diptera.”
20. Caladenia bifolia Hook. f.
My own record of this species (33) states that “the arrangement of the parts (of the flower) is so simple that an insect alighting on the labellum and advancing its head into the base of the flower could hardly fail to remove the pollinia; nor could one entering fail to leave these on the stigma, for in withdrawing pollinia from a flower they are always slightly depressed by the cap of the anther. The pollen is very incoherent, and the lower surface of the stigma projects a little, so that I am inclined to think self-fertilization takes place in flowers which have not been visited by insects. The majority of the flowers appear to set good capsules, and flowers which I fertilized artificially, produced good full seed-vessels.” Of 22 flowers growing in the open, 3 had both pollinia removed, in one the pollinia were removed from one anther lobe, in 5 others the pollen masses appeared more or less disturbed, while in the remaining 13 the anthers were untouched.
21. Corysanthes oblonga Hook f. D. Miller (in N.Z. Journ. of Science and Techn. 1 (1918) 4) describes Exechia Thomsoni, a fungus-gnat, which fertilizes this orchid.
21a. Corysanthes rivularis Hook f.
All the species of Corysanthes appear to be incapable of self-pollination, and from the evidence already acquired, the work is done by small Diptera, probably all of the Culicidae, and perhaps each species has its own particular fly. None of the flowers secrete nectar, but when the surface of the labellum is slightly punctured, a considerable amount of sweetish purple juice exudes, which is probably grateful to insects.
22. Corysanthes macrantha Hook. f.
I closely examined 143 flowers (33) and found that in 47 the pollinia were still in the anthers, from 90 they had been removed, while in 6, dead or living flies were found glued to the stigma. Of the whole number examined only a small proportion ultimately produced capsules. In addition to the insects which were caught by the viscid stigmas and which were unable to get away again, many flowers were found to contain only wings and legs of flies. This was due to the presence of small spiders which seemed to lie in wait for the flies which were entering the flowers, and in many cases captured them while inside. Indeed I think that all the insects which were found glued to the stigmas got caught there in their endeavours to escape from the spiders. In every case in which an insect was found by me withdrawing from a flower, the pollinia were removed also, securely attached to the front of the head. I regret that I did not preserve these flies, as I could not get them identified at the time.
23. Knightia excelsa R. Br.
Cheeseman (2) described the pollination of this species in 1882. He says “It is natural to assume that the transference of the pollen is done through the agency of insects, especially as the great abundance of honey induces many to visit the flowers. But in many cases they simply crawl about between the styles and never touch either the pollen or stigma elevated far above them. It appears to me that large insects only could aid in the work of fertilization; and even among these the nocturnal or crepuscular moths could be of little service, as the styles are far enough apart to allow of their proboscides being inserted without touching. Possibly some of the larger Diptera or Coleoptera, as well as the honey-bee (which is a regular visitant), may be of use; but the conclusion I have arrived at is that the flowers are principally adapted for a fertilization by honey-feeding birds such as the Tui (Prosthemadera) and Korimako (Anthornis). That the former bird regularly frequents the flowers I have repeatedly noticed, and old and observant residents, who were well acquainted with the Korimako before its disappearance from the northern forests, all agree in stating that it was equally ready to take advantage of the luscious supply of honey offered by the plant. The exact mode of fertilization hardly needs describing; it is obvious that the bird, in thrusting its head between the styles (stamens?) of a recently
expanded raceme, must dust the feathers of the forehead and throat with pollen, and that when it visited flowers in a more advanced stage, the pollen would be rubbed off on the style, and probably smeared over the stigma.”
24. Elytranthe Colensoi Engl.
The flowers of this handsome species have no scent and apparently no nectar. It is probable, however, that this is developed at some period of their being open, and that it attracts tuis and bell birds, but I have never actually seen the birds visiting the flowers.
25. Loranthus micranthus Hook. f.
The flowers are minute and green, but are sweet-scented, and are probably visited by small Diptera.
26. Tupeia antarctica Cham. and Schl.
The flowers are strictly dioecious. Both male and female flowers are very fragrant, and secrete a relatively large amount of nectar. They are much frequented by numerous midge-like Diptera, which in sucking the nectar from the flat discs bring the lower parts of their bodies into contact with the stamens or stigmas.
27. Dactylanthus Taylori Hook. f.
Townson, reported by Cheeseman (10) states that the scent of the monoecious flowers was so attractive to flies that all day long it was surrounded by a little crowd of them. Kirk (20) quotes Mr. Hill as saying that “he was enabled to discover the plant solely through the daphne-like fragrance which it emitted.” Mr. Hill, twenty-five years later (Trans. N.Z. Inst. 56 (1926) 89), says, “The perfume was overpowering.”
28. Muehlenbeckia australis Meissn.
In my paper (34) published in 1880) I stated that the species of this genus were dioecious or polygamous, destitute of scent and nectar, and that I had not noticed any insects visiting them. More recently, however, I have found two species of beetles (unidentified) visiting them, probably for the pollen.
29. Claytonia australasica Hook. f.
The flowers are very fragrant, have a little nectar at the base, and are visited by large numbers both of flies and moths, belonging to several distinct species.
30. Clematis indivisa Willd.
31. C. hexasepala DC.
I have never detected either nectar or fragrance in the flowers, and have assumed that they were visited for their pollen only. But in a note made on 30th October, 1898, I wrote that “I have been watching a hive bee and several species of flies on the flowers of C. indivisa. There must be some attraction beyond the pollen, for these insects were thrusting their trunks down to the bases of the filaments, and finding something grateful there.”
32. Clematis foetida Raoul.
The flowers are very strongly scented, at times almost over-poweringly so, but I have not seen insects on them.
33. Clematis marata J. B. Armstr.
34. C. quadribracteolata Col.
Cheeseman states (10) that both these species are sweet-scented.
35. Ranunculus Matthewsii Cheesem.
Cheeseman states (13) that this species is sweet-scented. It is probable also, that its nearest ally R. Buchanani Hook. f. is also fragrant. I have not detected either fragrance or nectar in the flowers of R. Lyallii Hook. f., or in R. nivicola Hook. f., nor in any of the smaller buttercups. Yet all seem fitted for insect pollination, and have one or more scale-like nectaries at the base of each petal. I have no record of insects visiting any species of Ranunculus.
36. Caltha novae-zealandiae Hook. f.
The flowers are sweet-scented, and are almost certainly entomophilous.
37. Carpodetus serratus Forst.
The flowers are conspicuous in their broad panicles. They are very fragrant and produce a large amount of nectar. They are also strongly proterandrous, but I have not detected any insects on them.
38. Pittosporum tenuifolium Banks and Sol.
The flowers have no perceptible fragrance, but have small beads of nectar at the base of the filaments. I have found two species of beetles visiting them, viz. Erirhinus limbatus, and Tigones caudata.
39. Pittosporum eugenioides A. Cunn.
The flowers are very fragrant and contain a considerable quantity of nectar between the bases of the filaments and the ovary. I have not seen insects on the corymbs, except introduced flies.
40. Pittosporum Dallii Cheesem.
According to Cheeseman (13) the fragrance of the flowers is an attractive characteristic.
41. Weinmannia racemosa Linn. F.
The flowers, which are in very conspicuous racemes, are sweet-scented, and contain a considerable quantity of nectar.
42. Rubus australis Forst.
The flowers are always dioecious; they are very sweet-scented and contain a considerable quantity of nectar. They are visited by many species of insects, some of which come for nectar, and some (the beetles principally) for pollen. I have found on them (34) numerous hairy Diptera of the size of a large house-fly, and also specimens of Syrphus novae-zealandiae. The following beetles are also common on the flower panicles:—
Empaeotes censorius, Pascoe; Hoplocneme Hookeri White; Cryptophagus castaneus Broun; (very abundant); Dasytes cinereohirtus Broun (common); Zorion minutum (common); Navomorpha sulcatus, and all the New Zealand species of Eugnomus. Phillpott states (30) that the moths Tatosoma agrionata, T. tipulata and T. timora are much attracted by the blossoms of Rubus.
43. Potentilla anserina Linn.
The flowers are faintly sweet-scented and contain a small quantity of nectar. In Europe this species is visited by numerous Coleoptera and Diptera, and by a few bees, but there is no record in New Zealand.
44. Carmichaelia grandiflora Hook. f.
Cheeseman states (11) that “the odour of the flowers is decidedly pleasant.”
45. Carmichaelia odorata Col.
Cheeseman quotes (11) Colenso, the first discoverer of this species as being “much impressed by the odour of the flowers which filled the air with their fragrance.”
46. Carmichaelia flagelliformis Col.
The flowers are very fragrant and contain a considerable amount of nectar, but no insects have been recorded as visiting them.
47. Clianthus puniceus Banks and Sol.
I stated (34) in 1880 that this species was visited by birds. The flowers have no scent, but the cup-like calyx contains a large drop of nectar. It is this which attracts the honey-birds (Anthornis), which search the blossoms with great diligence. Cheeseman (9) mentions that the Clianthus “was visited by a stray Kaka which spent the greater part of the day sucking the honey from the flowers.”
48. Sophora microphylla Ait.
The flowers are not fragrant, but they contain a quantity of nectar in the base of the calyx-cup. They are particularly attractive to tuis and bell-birds, but, according to Cheeseman (9) are not exclusively fertilized by birds.
49. Oxalis lactea Hook.
The flowers are without fragrance or nectar, and their stigmas get covered with pollen as the corollas wither, yet they appear to be incapable
of self-fertilization. I have kept numbers under glass and flowered them freely, but they never set a seed. They are probably pollinated by the numerous small Diptera which occur so abundantly in the bush.
50. Linum monogynum Forst.
The flowers are scentless and do not contain nectar, but from imperfect observations made by me, I gather that they do not produce seed when self-pollinated. I have only observed one species of fly on them, but this was not identified.
51. Phebalium nudum Hook.
Cheeseman (10) notes the fragrant character of the flowers.
52. Melicope simplex A. Cunn.
The flowers are usually unisexual, and are faintly sweet-scented. I have elsewhere stated (34) that “I think them entirely dependent for fertilization upon the small Diptera which so commonly frequent the edges of the bush.”
53. Pennantia corymbosa Forst.
The flowers are dioecious and very fragrant, and are evidently entirely dependent on insects for pollination.
54. Discaria Toumatou Raoul.
The flowers are almost oppressively fragrant and secrete a large quantity of nectar.
55. Elaeocarpus Hookerianus Raoul.
The flowers, though always hermaphrodite, are proterandrous. I have not observed any fragrance, but they produce a considerable amount of nectar at the base of the filaments.
56. Aristotelia racemosa Hook. f.
Usually dioecious, but ranging from “male flowers having no trace of a pistil to female flowers quite destitute of even the rudiments of stamens, and to hermaphrodite flowers having the full complement of both stamens and carpels.” They have neither fragrance nor nectar, but are visited — apparently for their pollen, — by several species of beetles, e.g. Cryptophagus castaneus, Dasytes cinereohirtus, and Erirhinus thomsoni.
57. Plagianthus divaricatus Forst.
Flowers dioecious, producing little or no nectar, but very fragrant.
58. Plagianthus betulinus A. Cunn.
Also dioecious, but very fragrant.
59. Gaya Lyallii J. E. Baker.
Hamilton (16) collected the following moths from flowers of this plant,— Declana floccosa, Melanchra rubescens, M. mutans and Leucania purdei.
60. Melicytus ramiflorus Forst.
The flowers are dioecious, very fragrant and contain much nectar. I have never detected any insects on them, but Oliver (22) when in the Kermadec Islands, found that lace-wing flies (Neuroptera) were visiting them.
61. M. lanceolatus Hook. f.
Also fragrant and nectariferous.
62. Pimelea longifolia Banks and Sol.
Flowers polygamous, dioecious and sweet-scented.
63. Pimelea prostrata Willd.
Flowers quite or nearly dioecious, fragrant, and with a considerable quantity of nectar in the perianth tube.
64. Leptospermum scopariuni Forst.
65. L. ericoides A. Rich.
Both species of Manuka have fragrant flowers which secrete a quantity of nectar. They seem to be chiefly pollinated by various beetles, of which I have taken three species, viz. Mordella antarctica, Pyronota festiva, and Arnomus brouni. Philpott (29) has also captured on them the moth Trachypepla euryleucota.
66. Leptospermum Sinclairii T. Kirk.
Cheeseman (11) quotes Kirk as saying that “the flowers are fragrant and are produced in immense profusion.”
67. Metrosideros lucida A. Rich.
The flowers of the Southern Rata are chiefly visited by tuis and bell-birds.
68. Metrosideros hypericifolia A. Cunn.
I reported this formerly (34) as sometimes visited by birds, but more probably by large Diptera, but I have not received further confirmation of this.
69. Metrosideros robusta A. Cunn.
Colenso states (11) that he thinks the moth Hepialus visits the flowers, which abound in honey.
70. Metrosideros villosa Sm.
According to Oliver (24) this Kermadee Island species is visited by tuis.
71. Metrosideros tomentosa A. Rich.
Visited by a beetle—Apion metrosideros—which, according to Broun, confines itself exclusively to this species.
72. Metrosideros scandens Sol.
The flowers of the White Rata have been a favourite collecting ground for many entomologists, and Hudson especially (17 and 18) has recorded the following species of Lepidoptera as frequenting them:—Orthosia comma Walk., O. communis Walk., Leucania atristriga Walk., Melanchra pelistis Walk., Erana graminosa Walk., Xanthorhoe beata Butl., Epirranthis alectoraria Walk., Selidosema productata Walk., S. aristarcha Meyr., S. panagrata Walk., Chalastra pelurgata Walk., Gonophylla nelsonaria Feld., Azelina gallaria Walk., A. ophiopa Meyr., Ipana leptomera Walk., and Vanessa gonerilla Fabr.
Also the following Diptera,—Arocera longirostris, and Eristalis cingulatus.
73. Myrtus obcordata Hook. f.
74. M. pedunculata Hook. f.
Both species have very fragrant flowers, which are distinctly proterandrous.
75. Fuchsia excorticata Linn. f.
The flowers of this species are largely pollinated by birds, a fact which has been recorded by several observers, the principal visitants being the tui and the bell-bird. Kirk (21) has the following note on the subject:—“The chief agents in effecting fertilization are the Tui (Prosthemadera novae-zealandiae), the Bell-bird (Anthornis melanura), and in the extreme north, the Stitch-bird (Pogonornis cincta). I suspect that the Parakeets (Platycercus novae-zealandiae and P. auriceps) assist in the process; the White-eye (Zosterops caerulescens) and, in some cases, the naturalised sparrow, although not honey feeders, certainly render assistance, as the blue pollen grains are frequently found on their feathers. They doubtless frequent the trees in search of insects, while the tui, the bell-bird and the stitch-bird are attracted by the honey.”
The only beetle recorded by Broun (34) as visiting the native Fuchsia is Oropterus coniger, but how far it assists in pollinating the flowers I do not know.
76. Nothopanax simplex Seem.
77. N. Edgerleyi Harms.
Both species are fragrant and contain a considerable quantity of nectar.
78. N. Colensoi Seem.
This species, which is also sweet-scented and nectar-producing, is visited by large hairy brown Diptera.
Hutton (19) refers to a kaka visiting a tall Panax for the nectar, but does not specify which.
79. Schefflera digitata Forst.
The flowers are fragrant and secrete much nectar. They are visited by very many flies, especially blowflies, but whether native or introduced, I cannot say.
I stated in 1880 (34) that “I believe that most of our flat-flowered hermaphrodite Umbelliferae are fertilized by Diptera (and perhaps minute Coleoptera).”
80. Aciphylla Colensoi Hook. f.
81. A. squarrosa Forst.
Both species are dioecious; their flowers produce abundance of nectar, and are very fragrant. They are visited by great numbers of Coleoptera and Diptera of several species.
82. Corokia Cotoneaster Raoul.
The flowers are sweet-scented, brilliantly coloured, and the base of each petal is furnished with a tuft or scale of glandular hairs which secrete a little nectar.
83. Gaultheria antipoda Forst.
This species is polygamous and in many cases dioecious. The flowers always contain a little nectar, but I have not detected any fragrance.
84. Gaultheria rupestris R. Br.
The flowers of this species also contain a little nectar, and are sometimes quite fragrant.
85. Pentachondra pumila R. Br.
The corolla tube is bearded within, and the flower is most probably pollinated by small long-trunked moths.
86. Leucopogon Fraseri A. Cunn.
The flowers are very fragrant. The corolla tube is thickly lined with hairs, and at its base contains a considerable quantity of nectar, which could only be reached by insects with relatively long slender trunks. Nearly always where Leucopogon is flowering numbers of small moths are abundant among the herbage.
87. Dracophyllum longifolium R. Br.
The flowers are in very conspicuous clusters, contain a great deal of nectar, and are very fragrant. They are occasionally visited by birds (34), and Philpott (30) has recorded a moth—Xanthorhoe umbrosa Philp.—as being common on flowers of plants growing at an elevation of 3,250 feet on the Hunter Mountains. He has also taken Aletia gourlayi on a Dracophyllum, probably this species.
None of the flowers of species of Gentiana examined by me have either nectar or scent, but they are so markedly proterandrous, that self-pollination seems to be impossible.
88. Parsonsia heterophylla A. Cunn.
The flowers are fragrant and contain a large quantity of nectar at the bottom of the tube, which can only be reached by an insect with a relatively long trunk. The pollen is contained inside a cap, and at first sight appears to be placed directly on the stigma. But the flowers are visited by numbers of moths, which probably cross-pollinate the flowers. Philpott (28, 29, and 30) has collected the following species of these flowers:—Leucania semivittata, Melanchra plena, M. diatmeta, Tatosoma timora, T. topea, Asaphodes megaspilata, and Xanthorhoe beata.
89. Myosotis Cheesemanii Petrie.
90. M. Traversii Hook. f.
91. M. concinna Cheesem.
92. M. macrantha Hook. f.
All these forget-me-nots are sweet-scented, the latter deliciously so, and are probably very attractive to insects, but I have no record of the fact.
93. Vitex lucens T. Kirk.
Petrie (26) states that “though the secretion of nectar is both abundant and long-continued, flying insects do not frequent the flowers. There is no doubt that pollination is effected exclusively by small birds. These constantly visit the flowers, hang on the rigid leafstalks or flower-stalks, and insert their bills into the corolla-tube to suck the nectar. In sucking the sweet juice the tui may be seen grasping a flower in one foot and turning it round into a more convenient position.”
94. Mentha Cunninghamii Benth.
The flowers are very fragrant and full of nectar; they are visited by numbers of small moths (unidentified) and probably by small Diptera.
95. Glossostigma elatinoides Benth.
Cheeseman (6) states—“I have not been able to systematically watch the flowers so as to ascertain what species are instrumental in transferring the pollen, but I have twice observed small Diptera engaged in sucking the flowers. Several of these I caught, and found grains of pollen on the foreheads of some of them.
The genus Veronica contains a very large number of species, and probably many hybrids, which are difficult of determination, and consequently both collectors of plants and insects have in most cases not attempted to identify the species. I have only direct observations on three of them.
96. Veronica salicifolia Forst.
The flowers are visited by great numbers of insects, chiefly Diptera and moths, besides one or two butterflies, including Vanessa gonerilla and V. itea.
97. Veronica elliptica Forst. visited chiefly by Diptera.
98. V. Traversii Hook. f.
Visited by great numbers of insects, chiefly Hymenoptera and Diptera; also some moths, including Nyctemera annulata.
99. Veronica pimeleoides Hook. f.
I have only observed a small blackish native bee (unidentified) on the blossoms.
The following insects have been collected on the flowers of various unidentified species of Veronica:—
Lepidoptera. Dodonidia helmsi, Leucania alopa, L. griseipennis, Melanchra pelistis, M. maya, Orthosia comma, and Xanthorhoe perfectata.
Diptera. Helophilus hochstetteri and Syrphus novae-zealandiae.
100. Rhabdothamnus Solandri A. Cunn.
Petrie (25 and 27) has found that the flowers are pollinated by tuis, and probably by bell-birds.
101. Utricularia monanthos Hook. f.
I examined this species carefully (34) and concluded that it is incapable of self-pollination, but that it was visited by small Dipterous insects.
102. Myoporum laetum Forst. f.
The flowers have little or no scent (34) but secrete a little nectar, which, however, is guarded from certain small insects by a lining of hairs in the corolla. The only insects I have observed on the flowers are small black beetles, —Dasytes Cheesemani.
103. Alseuosmia macrophylla A. Cunn.
The flowers are remarkably sweet-scented. Cheeseman states (11) that when Cunningham discovered the species, the plant was in full bloom, and the delicious fragrance of the flowers made such an impression upon him that he gave it its generic name Alseuosmia, from two Greek words meaning a grove and a sweet smell.
104. Pratia angulata Hook. f.
The flowers are faintly sweet-scented and have a considerable quantity of nectar. They are proterandrous and quite incapable of self-pollination.
105. Wahlenbergia gracilis Schrad.
106. W. albo-marginata Hook.
Both species are evidently quite dependent on insect aid for their pollination (34). The flowers are markedly proterandrous and secrete a small amount of nectar. I have taken a beetle—Dasytes Cheesemani on W. gracilis.
107. Selliera radicans Cav.
Cheeseman (5) states that the flowers are visited by numerous insects of various orders, but considers that fertilization is chiefly effected by Diptera. Of these “some 12 or 13 species have been observed, some of which, however, are of small size and but poorly fitted for the work of transporting pollen. Two or three Hymenoptera have been noticed, including the hive-bee. I believe that several nocturnal Lepidoptera are constant visitors. A butterfly — Leptosoma annulatum — has often been seen similarly engaged. One species of the Staphylinidae is not uncommon about the flowers.”
118. Scaevola gracilis Hook. f.
Cheeseman (10) states that the flowers are sweet-scented.
109. Donatia novae-zealandiae Hook. f.
I have not detected fragrance or nectar in the flowers, but they are produced in such conspicuous masses, and their pollen is so adhesive, that they suggest pollination by insects. Hudson (17) has captured Chrysophanus boldenarum on the flowers.
A great many species of this order are evidently entomophilous, but very few insects have been identified as associated with the pollination of their flowers. I have only recorded a few observations on the order. Olearia macrodonta Baker, O. ilicifolia Hook. f., O. arborescens Cockayne and Laing, O. fragrantissima Petrie, O. Hectori Hook. f., O. odorata Petrie and O. virgata Hook. f., are all more or less powerfully fragrant. Of the genus Celmisia I have observed slight fragrance and a little nectar in C. gracilenta Hook. f., but can hardly doubt but that many other species are similarly endowed with attractions for insects. Other fragrant species are Helichrysum bellidioides Willd., Cassinia fulvida Hook. f., Brachyglottis Rangiora Buch., (which is visited especially by a beetle Rygmodus modestus) Senecio rotundifolius Hook. f., and S. Bidwillii Hook. f. Several species of Senecio, though scentless, produce a little nectar, such as S.
lagopus Raoul, S. bellidioidea Hook. f., S. Lyallii Hook f., and S. lautus Forst.
To summarize the position, it is quite evident that only a small proportion of the flower-visiting insects have been actually dealt with, but I have no means of knowing what that proportion is.
Similarly only some 120 plants have been specifically referred to, which is less than 8 per cent. of the total number of known species. Of course whole orders such as the Cyperaceae, Gramineae, and all their allies, are either anemophilous or are wind-pollinated; as are whole genera of other orders, e.g. Coprosma. On the other hand, though there is no direct evidence on the subject, the vast majority of the New Zealand representatives of such orders as the Orchidaceae, Scrophulariaceae, Onagraceae, Leguminosae, etc., and of such genera as Celmisia, Olearia, Myosotis, Gentiana, Dracophyllum and many others, are certainly entomophilous.
My main object, therefore, in drawing up this paper, is to urge on both entomologists and botanists a closer examination of their collected material from this standpoint of the inter-relation of the two groups. Experimental work also on a great number of hermaphrodite flowers will show that they are quite infertile with their own pollen. I have already shown this for a few species, and it is a matter which could easily be tested by cultivators of native flowers.
The subject is one which members of field clubs could do much to elucidate. Many such embryo naturalists are content to collect a few plants or insects, or even only to watch (not necessarily to observe) while others collect, under the erroneous impression that they are not competent to add to the sum of scientific knowledge. Every one who will take the trouble to record the simplest observation made, may bring to light some fact of scientific importance, and it is by the accumulation of such little recorded facts that much of our knowledge of natural history is built up.