Bijdragen tot de Dierkunde, 63 (4) 193-220 (1993) SPB Academie Publishing bv, The Hague To make a meadow it takes a clover and a bee: the entomophilous flora of N.W. Europe and its insects .** Willem N. Ellisi* & Albertine C. Ellis-Adam *Institute of Taxonomie Zoology (Zoological Museum), University of Amsterdam, Entomology Department, Plantage Middenlaan 64, 1018 DH Amsterdam, The Netherlands; **Hugo de Vries Laboratory, University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands Keywords: flower-visiting insects; insect conservation; anthophilous fauna; cornucopian species; flower types; integrated pest management Abstract Résumé An of the fauna of N.W. is Est de la faune du analysis anthophilous Europe pre- présentée une analyse anthophile d’Europe sented, stressing the role plants play for insects. The study is nord-ouest, soulignant le rôle joué par les plantes pour les in- 29.000 based onsome 29,000 relations between about 2,600 insect spe- sectes. L’étude est basée sur environ relations entre envi- cies and The data derived 1,300 plant species (569 genera). are ron 2.600 espèces d’insectes et 1.300 espèces de plantes appar- from database of biotic relations our (“CrypTra”) between tenant à 569 genres. Les données sont dérivées du database éla- Cryptobiota and Tracheophyta, that is based on published boré les des relations par auteurs (“CrypTra”) biotiques entre sources. Cryptobiontes et Tracheophytes, database s’appuyant sur des It is suggested that a ratio of 2 to 5 insect species anthophilous sources publiés. per entomophilous plant species is the rule in N.W. Europe, On suggère quele rapport 2 à 5 insectes anthophilespar espèce where other types of zoophily are virtually absent. végétale entomophile est de règle en Europe du nord-ouest (où A small minority of the plant species/generaplay a dispropor- d’autres types de zoophilie sont pratiquement absents). tionallyimportantrole as hosts to flower visitors; many ofthese Une faible minorité d’espèceset genres deplantes joueun rôle so-called cornucopian taxa belong to the commonest ento- démesurément important en tant que hôtes des visiteurs des mophilousplants in the region, and occur also in moderatelydis- fleurs; beaucoup de ces “taxons cornucopiens” sont parmi les turbed habitats. plantes entomophilesles plus communes de la région,présentes There is a significant positive correlation between the com- aussi dans des habitats modérément modifiés. monness of a plant species and the fraction this plant represents Il y a une corrélation positive significative entre l’ubiquité of the trophic resources exploited by an insect species. There is, d’une espèce végétale et la fraction représentée par cette plante on the otherhand, a significant negative correlation between the dans l’ensemble des ressources trophiquesexploitées par une es- number of insect species visiting a given plant species, and the pèce d’insectes. Il y a, d’autre part, une corrélation négative sig- number of plant species visited by a given insect species. These nificative entre nombre d’espèces d’insectes fréquentant unecer- two elements together demonstrate that the anthophilous fauna taine espèce végétale,et nombre d’espèces de plantesfréquentées and the entomophilous flora of N.W. Europe as a whole form par une certaine espèce d’insectes. L’ensemble de ces deux élé- a loose system, not predominantly characterised by speciali- ments démontre que la faune anthophileet la flore entomophile sation. du nord-ouest forment lâche d’Europe un système qui n’est pas In accordance with this, factor analysis suggests that there is caractérisé en premier lieu par la spécialisation. no ground to recognise more than three visitor types, viz., the En concordance avec ceci, l’analyse factorielle suggère qu’il allotropous, hemitropous, and eutropous visitors as defined by - n’y a pas lieu de reconnaître plus de trois types de visiteurs, à Loew. A minorityofthe plant taxa essentially the cornucopian savoir les visiteurs et - tels - allotropes, hemitropes eutropes ones can with some difficulty be associated with these three qu’ilsont été définis par Loew. Une minorité de taxons végétaux types of visitors, and a very few narrowly specialised plant taxa (essentiellementespèces cornucopiennes) être associeé, avec can be associated with more specific visitor groups. However, peut une certaine à ces trois de visiteurs, tandis que the large majority of plants cannot be fitted in any typology. difficulté, types très de taxons étroitement spécialisés These results have practical implications for the nature peu végétaux peuvent être associés à des de visiteurs. management of the anthophilous fauna, in that the important groupes plus spécifiques Cependant, role of the cornucopian floral element is underlined. The fact il est impossible de ranger la grande majorité des plantes dans certaine that the majority of the cornucopian species are perennial, or une typologie. evenwoody, places constraints to agriculturalpractices intended Ces résultats ont des implications pratiques pour la gestion to foster beneficial anthophilous insects. naturelle de la faune anthophile,le rôle important des éléments - 194 W.N. Ellis & A.C. Ellis-Adam To make a meadow it takes a clover and a bee Le floristiques cornucopiens dans ce domaine étant souligné. formulated qualitatively. The studies of Müller fait majorité cornucopiennes vivaces ou que la des espèces sont (1873-1881), De Vries (1875), Heinsius (1892), même ligneuses, certaines contraintes aux procédés agri- pose Knuth (1892-1905), Willis& Burkill (1895-1908), coles ayant pour but la protection des insectes anthophiles utiles. to mention the most important ones, brought to- information awaited gether a wealth of factual that analysis for another century. Motto One more researcher is worthy of mention, viz. Julius Mac Leod. Of his studies on the anthecology Die Schirmblumen of the Kempen region in Belgium, the first part Leod diese ist appeared precisely one century Mac .... Denn Saftdrüse zugleich die Saftbehalter. Da ago. nun der auf derselben befindliche Saft an der freyen Luft (1893-1894) wrote this masterpiece of observation liegt, und durch nichts gedeckt wird, so scheint derselbe von and analysis because he was convinced that only a dem Regen keineswegs geschützt zu seyn. Allein erstens ist detailed, regional, study of, on the one hand, the derselbe nicht eigentlich für Bienen und Hummeln be- visitors, their morphology and ethology, and on the stimmt, welche in Ansehung des Safts sehr ekel sind, und the flowers with their and einen mit Regenwasser vermischten Saft verschmähen, da other, morphology phys- sie sich aus andern Blumen einen solchen Saft zu ver- iology would enable a definite explanation of the schaffen wissen, der schlechterdings nicht vom Regen ver- functionality of flowers and their diversity. Essen- dorben werden kann. Sondern derselbe ist hauptsächlich these two tially, papers form the documentationof für Fliegen und andere unedlere Insekten bestimmt. Weil an earlier one (Mac Leod, 1889) in which he intro- diese zu dumm sind, um den in andern Blumen tiefversteck- duced an innovative method in ten und vor dem Regen völlig gesichertenSaft ausfindig zu (Van Paemel, 1992) machen; so haben sie keinen so feinen Geschmack, als die botany, which in retrospect can best be described as der Bienen und Hummeln, sind in Wahl desselben nicht so a graphical anova, to analyse the Belgian antho- ekel, sondern nehmen auch mit einem durch den Regen ver- philous fauna. Mac Leod's "graphical method" dorbenen Saft vorlieb. ... was later applied by Loew (1890) and Heinsius C.K. Sprengel, 1793:154. (1892). We present Mac Leod's (1893, 1894) data, to- gether with the often less detailed observations of Introduction other authors, to study the quantitative relationbe- tween the floral assemblage of N.W. Europe and The study of the relation between flowers and their the diversity of its anthophilous fauna. Such a visitors has tradition. a long Precisely 200 years broad-based approach was chosen, because pres- ago, Christian Konrad Sprengel (1793) published ent-day anthecology is mainly directed to individual his famous book "Das entdeckte Geheimniss now plant species that are particularly suited to unravel- der Natur im Bau und in der der Blu- Befruchtung ling specific problems. As aresult, the large majori- men", in which he single-handedly laid down the ty of plants which are unspecialised has received foundations of pollination biology. This major little attention. This leaves an ecologist or conser- contribution has been amply celebrated in 1893 vationist with no other option to support a predic- (references in Knuth, 1893, 1898-1905) and in 1993 tive statement, than to resort to traditionaltypolo- too there will be held at least two commemorative gies to register a plant as a "fly flower", "bee flow- symposia. Sprengel's main discovery was the mu- er", or, vaguest of all, "beetle flower" (Kugler, tual adaptation of flowers and their pollinators 1970; Van der Pijl, 1961). This is exacerbated by (Faegri & Van der Pijl, 1979; Meeuse & Morris, the fact that supposedly inefficient pollinators, like 1984). Coleoptera and Acalyptrata, have received com- A century after Sprengel a number of workers paratively little attention from modern anthecolo- with admirable tried, perseverance but with the gy (but see e.g. Brncic, 1966; Gottsberger, 1977; limited computational tools of their time, to estab- Kugler, 1951, 1984; Sabrosky, 1987). lish the thesis that had concen- quantitatively Sprengel Pollination biology by its very nature Bijdragen tot de Dierkunde, 63 (4) - 1993 195 trates on the role insects and other vectors play in manifest mostly in rare organisms. the pollination of plants. Thatalternatively flowers The first pair of alternatives tests whether the an- often role in the exis- fauna play an important, crucial, thophilous as a whole can be regarded as of insects has been studied less often in such It be reasoned that tence specialised. may common plant detail (and then mostly for bees: cf. Magers, 1970; species receive more visitors, both by numbers of Pellet, 1976; Probst, 1983; Westrich, 1989; but see species and individuals of anthophiles, than rare et Weiss e.g.