The role of the loquat in maintaining entomological diversity in the Conca d'Oro orchards of Sicily

Abstract

The loquat [Eriobotryo japonica (Thumb.) Lindl.] is an allochthonous species long cultivated in Sicily. In some parts of Sicily such as the Siracusa province, the loquat is cultivated in mono-specific orchards. In other sites, like Conca d'Oro and other places near the town of Palermo, loquat is intercropped with other tree species such as citrus, apricot, peach, mulberry, walnut, Mediterranean hackberry. The loquat plays an important role in order to increase biodiversity within these orchards. The old or dead loquat trees host a variety of xylophagous insects and more in particular Coleoptera: Cerambycidae beetles Dynastidae, and Cetoniidae. Longhorn beetles, rhinoceros beetles and flower beetles are usually considered excellent indicators for woodland biodiversity and, particularly, for the wood decomposer community. However, they have never been associated to fruit orchards. Instead, in old or abandoned orchards, it is common to find live trees with dead parts or dead trees which host a rich community of decomposer insects. Today, farming changes or collapses in the urban surroundings have partly contributed to erasing this diversity. Research carried out in the past years has pinpointed that the loquat plays an important role in the preservation of different species, particularly Cerambycidae, such as: Aegosoma scabricorne, Cerambyx scopolii, Penichroa fasciata and Niphona picticornis. These species have been recorded as stable populations in many loquat orchards of the agricultural surroundings of the town of Palermo, where the presence of suitable natural environments for these beetles is rare. Some of these species are included in the red list of the sapro-xylophagous insects.