The role of native flower visitors in pollinating Opuntia ficus-indica (L.) Mill.,naturalized in Sicily

The role of insects in pollination and consequently in fruit set and quality was assessed in twocommercial orchards of the cactus pear, Opuntia ficus-indica (L.) Mill., in Agrigento Province, Sicily. In1997, insects visiting flowers were sampled during MayeJune (the first bloom) and July (the secondbloom, induced by the “scozzolatura” practise). More than 50 insect species belonging to 10 orders werecollected in MayeJune, while only five species of Hymenoptera Apoidea were collected in July. Thequality of fruits arising from the second bloom showed that Hymenoptera alone were able to guaranteeeffective pollination. To verify the role of insects in pollination in 1996 (during only the second bloom),and in 1997 and 2009 (during both blooms), 60 single flowers were marked during each bloom; 30 ofthem covered with paper sleeves (which prevented natural pollination), while the others were notcovered. After withering, fruits produced by marked flowers were analyzed in laboratory: in all years andblooms, the total number of seeds, the number of developed seeds, and the weight and the percentage ofpulp were significantly lower for covered flowers than for non-covered flowers. The results are consistentwith the hypothesis that native insects effectively carry out the pollination of cactus pear flowers.