Orchid pollinators discovered in insect collections
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Vladimir Nazarov1, Ulf Buchsbaum2 and Axel Hausmann2
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1 - Isarweg 37, D - 84028 Landshut, Germany; e-mail:
2 - Zoologische Staatssammlung München Münchhausenstr. 21, D - 81247 München, Germany; e-mail:
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Abstract
Orchid pollinaria can be detected easily on insect pollen-vectors in the field as well as in collections.
On the poster, the results from the analysis of pollinaria charge on various families of Lepidoptera
(Zygaenidae, Noctuidae) are presented. Out of the material of the ZSM and the Museum Witt about 63,000
specimens have been examined from 15 countries. 421 vectors could be found for Anacamptis pyramidalis,
63 for Platanthera chlorantha and 17 for Gymnadenia spp. The identification of pollinaria of these orchid
species was not complicate because its unique morphology. Additionally each orchid species shows a
characteristic pattern of localization of the pollinarium on different head parts of the insects.
Proceedings of the 18th WOC, March 11-14, 2005, Dijon - France. 340-342
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Introduction
It is well-known that pollination in most orchid species can rarely be observed. But pollen aggregates of
orchid pollinia are easy to detect on the pollinators. Morphology of pollinia or pollinaria is unique in
some species, facilitating rapid assessment of orchid pollen vectors by examination and analysis of insects
in collections.
Materials and Methods
The Lepidoptera material of the Zoologische Staatssammlung München and the Museum Witt has been examined
for orchid pollinaria.
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Results
We exanimated of about 63,000 specimens of Lepidoptera and found 480 insects with orchid pollinaria.
Most pollinaria belong to 3 orchids: Anacamptis pyramidalis (L.) L.C.M. Richard, Platanthera chlorantha
(Custer) Reichenb. and Gymnadenia conopsea (L.) R. Br. Species of the genus Zygaena Fabricius, 1775
(Lepidoptera, Zygaenidae) have been identified as pollinaria vector of A. pyramidalis. 421 specimens of
15 species are carried by 826 pollinaria on its proboscises. We found 132 specimens with 296 pollinaria
(132 / 296) for Z. lavandulae (Esper, 1783), 100 / 231 for Z. purpuralis (Brünnich, 1763), 78 / 110 for
Z. loti (Denis & Schiffermüller, 1775), 46 / 74 for Z. filipendulae (Linnaeus, 1758).
Zygaena specimens with pollinaria of A. pyramidalis have been captured in more than 90 localities from 12 European countries,
Caucasus and Morocco (Fig. 1).
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Fig. 1. The distribution of orchids pollen vectors:
 - Zygaena specimens with load of Anacamptis pyramidalis pollinaria;
 - Noctuid moths with load of Platanthera chlorantha and Gymnadenia spp.
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Different species of Autographa Hübner, 1821, Macdunnoughia confusa (Stephens, 1850) and
Plusia putnami gracilis
Lempke, 1966 (Noctuidae, Lepidoptera) were detected with hemipollinaria of Platanthera chlorantha and
Gymnadenia spp. On the eyes of 63 specimens of 4 species were found hemipollinaria P. chlorantha. The
hemipollinaria G. conopsea were detected on proboscises of 17 specimens, which belong to 5 species (Table 1.).
All hemipollinaria vectors were collected in the 9 localities of Bavaria (Germany) between 1895 and 1981
(Fig. 1). P. chlorantha hemipollinaria have been found on collection specimens of on Geometrid moths by
Hausmann (2004), this moth family needs more extensive studio to investigate their importance as orchid
pollinators.
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Discussion
All orchid pollinaria in this research were identified on the base of their unique morphology. Identification
of the polli- naria of A. pyramidalis was easy. Both caudicles of pollinaria of this orchid are joined in one
viscidium. This morphological particularity is very rarely observed in European Orchids. Additionally the
viscidium of A. pyramidalis has a unique "saddle-shaped" form (Fig. 2), which was successfully used by
Charles Darwin (1862) to assign the pollinaria of this orchid on 23 species of Lepidoptera.
Pollinaria of Platanthera as well as those of most European orchid species are subdivided into two parts (Fig. 3).
Each caudicle has got a separate viscidium, which can be separately removed by pollinators. So we have
designated this structure as hemipollinarium according to Dressler (1981) to stress its difference from the
pollinarium. We have identified hemipollinaria of Platanthera species on the base of their characteristic
pattern of localization on the head parts of the moth and the morphology of viscidia and caudicle. The
eye-attached hemipollinaria of P. chlorantha (Cust.) Reichb. have circle-shaped viscidia and its caudicle is
longer than the pollinium (Fig. 3 A). In contrast to that there are the tongue-attached hemipollinaria of
P. bifolia (L.) L. C. Rich. with elliptical viscidia and a caudicle shorter than the pollinium (Fig. 3 B)
(Nilsson 1983; Maad and Nilsson 2004). It is well-known that in localities with sympatric occurrence of
P. chlorantha and P. bifolia, there my hybrids with an intermediate form of hemipollinaria (Nilsson 1983, 1985).
However, all hemipollinaria we have discovered were typical for P. chlorantha. They were localized on the eyes
of the moths. In hemipollinaria vectors the distance between the distal margins of both eyes varied from 2.75
to 3.40. This corresponds to the distance between both viscidia of P. chlorantha (Nilsson 1978).
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Fig. 2. Pollinaria of Anacamptis pyramidalis: A - 3 pollinaria on proboscis of Zygaeana purpuralis.
B - The pollinarium after removing of one caudicle for better view of viscidium (SEM). c- caudicle;
m - massulae of pollinia; v - viscidium.
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Fig. 3. Morphology of hemipollinaria (SEM): A - Platanthera chlorantha, B - P. bifolia, C - Gymnadenia
conopsea, D - G. odoratissima; L - length of caudicle, W -width of caudicle.
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Another sympatric species pair, Gymnadenia conopsea (L.) R. Br. and G. odoratissima (L.) Rich., differs
from each other in morphology of hemipollinarium, but less apparently than Platanthera spp. (Fig. 3).
However, to a very certain extent we can state that hemipollinaria of G. conopsea differed from those of
G. odoratissima in length/width ratio of caudicle (Nazarov and Buchsbaum 2004). On this base we have identified
hemipollinaria G. conopsea on 9 Noctuidae speciments. Other moths with hemipollinaria Gymnadenia need
destruction of proboscises for sure identification of orchids.
We are sure, that a successful identification of pollinaria/hemipollinaria on the collected insect is possible
also for the polymorphic genera of European orchids. Accurate morphometrical information with measurements
of their caudicle, viscidia and pollinia are needed. To facilitate a large-scale data collecting we have
already implemented a Pollinium Database.
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Acknowledgements
The authors thank Thomas Witt (Munich) for his contributions to this project and Tanja Kothe (Munich) for
her help with SEM.
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References
Darwin, C. 1862. On the various contrivances by which British and foreign orchids are fertilized by insects. Jon Murray, London. 300 p.
Dressler, R. L. 1981. The orchids: natural history and classification. Cambridge, 332 p.
Hausmann, A. 2004. The Geometrid Moths of Europe 2. Sterrhinae. Apollo Books, Stenstrup, 600 p.
Maad, J., and L. A. Nilsson. 2004. On the mechanism of floral shifts in speciation: gained pollination efficiency from tongue- to eye-attachment of pollinia in Platanthera (Orchidaceae). Biol. J. Linn. Soc. 83: 481-495.
Nazarov, V., and U. Buchsbaum. 2004. Widderchen als Bestäuber von Orchideen in Thüringen (Insecta: Lepidoptera, Zygaenidae). Entomofauna. 25: 365-372.
Nilsson L. A. 1978. Pollination ecology and adaptation in Platanthera chlorantha (Orchidaceae). Bot. Notiser. 131:35-51.
Nilsson, L. A. 1983. Processes of isolation and introgressive interplay between Platanthera bifolia (L.) Rich.
and P. chlorantha (Custer) Reichb. (Orchidaceae). Bot. J. Linn. Soc. 87: 325-350.
Nilsson, L. A. 1985. Characteristics and distribution of intermediates between Platanthera bifolia and P. chlorantha (Orchidaceae). Nord. J. Bot. 5: 407-419.
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Citation rule: Nazarov V. et al. 2005. Orchid pollinators discovered in insect collections. Proceedings of the 18th WOC, March 11-14, 2005, Dijon - France. 340-342
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© 2005 Dr. Vladimir Nazarov
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