Honeydew producers in eucalypts and associated native fauna

• Author(s): Nunes, Pedro Mourato Catela
• Date: 2017
• Persistent ID: http://hdl.handle.net/10400.5/13884
• Origin: Repositório da UTL
• Subject(s): eucalypts; psyllids; honeydew; biological invasions; native fauna
• Document Type: Master thesis
• Language: English
• Contributor(s): Repositório da Universidade de Lisboa

Description

Mestrado em Gestão e Conservação de Recursos Naturais - Instituto Superior de Agronomia - UL / Universidade de Évora

In recent years there has been an increase in the number of introduced eucalypt-feeding invasive species in worldwide plantations outside Australia. A large portion of these are honeydew producing sap-suckers, mostly psyllids (Hemiptera: Psylloidea). Besides the negative impact on eucalypt production, these non-native honeydew producers may have ecological effects on local native fauna by establishing new interactions. In this work, we intended to study these new interactions in eucalypt plantations in Portugal. We surveyed during a year three invasive psyllid species, Glycaspis brimblecombei, Ctenarytaina spatulata and Ctenarytaina eucalypti, in two sites with eucalyptus trees in Lisbon. The two sites differed on species composition and tree age. For each psyllid species, we estimated the population abundance and identified the associated fauna present in each survey date, covering the activity period of the psyllids. We also analyzed the sugar composition of honeydew and lerp produced by G. brimblecombei. With these results, we intended to further understand how sugar composition of these products may influence the associated fauna. The three psyllid species differed on their seasonal activity. The two Ctenarytaina species were observed from January to June, whereas G. brimblecombei concentrated its activity between May and September. Several commensal and predatory native species were found associated with the psyllids, as well as two exotic Australian parasitoid species. The number of specimens and species richness of both native commensals and predators was significantly higher for G. brimblecombei in comparison with the two other psyllid species. The main sugar present on G. brimblecombei honeydew and lerps was fructose. This work offers contributions for the eucalypt plantation management towards the psyllid species, for the study of the how invasive honeydew producing species affect the native fauna and finally serving as a guideline for future studies in the honeydew sugar compositions and its effect on the fauna attractiveness of the honeydew