A critical role for Copestylum larvae (Diptera, Syrphidae) in the decomposition of cactus forests

作者：Martinez Falcon A P^*; Marcos Garcia M A; Moreno C E; Rotheray G E

来源：Journal of Arid Environments, 2012, 78: 41-48.

DOI：10.1016/j.jaridenv.2011.10.010

• Barranca de Metztitlan biosphere reserve
• Cactaceae
• Decay rate
• Ecosystem process
• Isolatocereus dumortieri
• Mexico
• Saprophagous hoverflies

We carried out a field experiment during the rainy seasons of 2008 and 2009 to determine the role of insects in the decomposition of Isolatocereus dumortieri (Scheidweiler) Backeberg (Cactaceae), an endemic columnar cactus from semi-arid scrublands of central Mexico. In both years, after 120 and 95 days respectively, uncovered cactus sections were all colonized by insects. Apart from a few beetles (Coleoptera), the most abundant insects found were larvae of up to six species of Copestylum (Diptera, Syrphidae). We recorded 1859 larvae in 2008 and 1626 in 2009. The cactus decomposition rate was significantly faster when insects were present, and the C/N proportion varied over the decomposition process. We also found a pattern of turnover in the relative abundance of Copestylum species over time. Our results provide evidence that syrphids play an important role in the decomposition of cacti.

• 出版日期2012-3