Influence of tree hollow characteristics on the diversity of saproxylic insect guilds in Iberian Mediterranean woodlands

Saproxylic diversity assessment is a major goal for conservation strategies in woodlands and it should consider woodland composition and configuration at site and tree level as key modelling factors. However, in Mediterranean woodlands little is known about the relation with the environmental factors that structure their assemblages, especially those linked to tree hollow microhabitats. We assessed the diversity of Syrphidae (Diptera) and Coleoptera saproxylic guilds that co-occurred in tree hollows located in three different Iberian Mediterranean woodlands in the Cabañeros National Park (Spain). Furthermore, we evaluated how differences in tree hollow microenvironmental variables (understood as the physical and biotic characteristics of a hollow and tree individual) influenced saproxylic guild diversity both within and among woodland sites. We found that woodland sites that provided greater heterogeneity of trees and hollow microhabitats determined higher saproxylic guild diversity. Nevertheless, certain species or even complete guilds can be favoured in woodlands where some hollow microhabitats predominate as a consequence of historical tree management. In general, hollow volume was the main determining factor for saproxylic guild richness and abundance in woodland sites, and large hollow volume was usually related to higher diversity, which highlighted the importance of multi-habitat hollow trees. Moreover, saproxylic guilds also responded to other different microenvironmental variables, which indicated different ecological preferences among guilds. The conservation of saproxylic insects in Iberian Mediterranean areas must be addressed to protect woodland sites that provide high diversity and large numbers of tree hollow microhabitats, and practices to enhance microhabitat heterogeneity should even be encouraged.

Where Is My Food? Brazilian Flower Fly Steals Prey from Carnivorous Sundews in a Newly Discovered Plant-Animal Interaction

A new interaction between insects and carnivorous plants is reported from Brazil. Larvae of the predatory flower fly Toxomerus basalis (Diptera: Syrphidae: Syrphinae) have been found scavenging on the sticky leaves of several carnivorous sundew species (Drosera, Droseraceae) in Minas Gerais and São Paulo states, SE Brazil. This syrphid apparently spends its whole larval stage feeding on prey trapped by Drosera leaves. The nature of this plant-animal relationship is discussed, as well as the Drosera species involved, and locations where T. basalis was observed. 180 years after the discovery of this flower fly species, its biology now has been revealed. This is (1) the first record of kleptoparasitism in the Syrphidae, (2) a new larval feeding mode for this family, and (3) the first report of a dipteran that shows a kleptoparasitic relationship with a carnivorous plant with adhesive flypaper traps. The first descriptions of the third instar larva and puparium of T. basalis based on Scanning Electron Microscope analysis are provided.

Insecta Saundersiana : or, Charcters of undescribed insects in the collection of William Wilson Saunders.

v.4 (1858) [Homoptera]

Katalog der Paläarktischen dipteren / bearbeitet von Th. Becker ... [et al.].

Bd. 2

Catalogus dipterorum hucusque descriptorum /

v. 3 (1908)

Katalog der Paläarktischen dipteren / bearbeitet von Th. Becker ... [et al.].

Bd. 4

Katalog der Paläarktischen dipteren / bearbeitet von Th. Becker ... [et al.].

Bd. 3

Catalogus dipterorum hucusque descriptorum /

v. 6 (1909)

Catalogus dipterorum hucusque descriptorum /

v. 7 (1910)

Katalog der Paläarktischen dipteren / bearbeitet von Th. Becker ... [et al.].

Bd. 1

Catalogus dipterorum hucusque descriptorum /

v. 4 (1909)

Catalogus dipterorum hucusque descriptorum /

v. 5 (1909)

List of the specimens of British animals in the collection of the British Museum.

pt.15 (1853) [Nomenclature of Diptera.I]