S. Mahunka szerk.: Folia Entomologica Hungarica 28/2. (Budapest, 1975)
ted nectar only. In case of species gathering pollen regularly the ratio of pure loads was much less than expected, namely 65 per cent of the analyzed loads was contaminated and 31 per cent of them contained more than 2 per cent foreign pollen (Table 2). 40 per cent of the loads contained at least traces of Compositae, 26 per cent of Papilionaceae and 16 per cent of Umbelliferae pollens. This observation can be explained by the fact that most of the recorded bee species show preference mainly to these plant families (Table 3) and none to Liliaceae or specially to onion. Wasps captured in seed onion fields seem also to be related to families other than Liliaceae, bacause their preferred foodflowers belong, first of all, to Umbellifera and Compositae (Table 3). All the above facts seem to indicate that specialized flower visitort of onion are absent in our hymenopterous fauna, since its inflorescences fail to be primary food sources of wild bees and wasps visiting blooming seed onion fields. Their appearance, therefore, seems to be accidental only in onion. This conclusion can explain the variability of both the structure and the density of their populations in the crop and, simultaneously, points the necessity of moving honeybee colonies to blooming onion fields for obtaining sufficient seed set and yield. Irodalom - References 1. AGATI, G. (1952): Indagini e osservazioni sulla biológia florale délia cippola.Ortoflorofruttic. ital., 36: 67-77. 2. BENEDEK, P. (1968): A hazai kaparódarazsak (Hym., Sphecoidea) élőhelyi viszonyai és viráglátogatása - Fol. Ent. Hung., 21:.63-88. 3. BENEDEK, P. (1969): Flower visiting habits of lucerne.pollinating wild bees and the increasing of wild bee populations by providing unbroken feeding possibilities. - Z. ang. Entomol., 63: 186-199. 4. BENEDEK, P. (1971): Flower visiting habits of colletid and melittid bees (Hymenoptera, Apoidea) based on data originating from Hungary. -Mushi, 45: 65-79. 5. BENEDEK, P. (1974): Vöröshagyma. - In: Benedek P., Manninger S. és Virányi S.: Megporzás mézelő méhekkel.-Mezőgazd. Kiadó, Budapest, p. 154-164. 6. BENEDEK, P. és GAÁL E. (1972): The effect of insect pollination on seed onion, with observations on the behaviour of honeybees on the vrop. - J. apicult. Res., 11. p. 175-180. 7. BENEDEK, P., MARTINOVICH V. és GAÁL E. (1975): Magtermő vöröshagyma táblák megporzó rovarnépességeinek összetétele és sűrűsége. - Zöldségtermesztés, nyomás alatt. 8. BOHART, G.E., NYE, W.P. és HAWTHORN, L.P. (1970): Onion pollination as effected by different levels of pollinator activity. - Utah. Arg. Expt. Sta. Bull., No. 482. 9. DYLEWSKA, M. (1974): Podrodzina Andreninae. - In: Klucze do oznaczania owadow Polski, Panstwowe Wydawn .— Nauk ., Warsawa, No. 84. 10. KORDAKOVA, Z. M. (1956): Medonosznü pcselü x opülenie szemennikov reposatovo luke. - In: Kriscsunasz. I.V. i Gubin, A . F .: Opülenie szelszkohozjajsztvennüh rasztenij pcselami.—Izd. Szol. Lit., Moszkva, p. 163-171).
