Colonization and Abandonment of Host Trees in a Natural Setting on Key Largo, Florida by the Treehopper, Umbonia crassicornis (Amyot and Serville) (Hemiptera: Membracidae)

Abstract

Abstract. This study examined the use of individual host trees by the membracid, Umbonia crassicornis (Amyot and Serville). To do this we monitored the number of U. crassicornis in six classes: solitary female, solitary male, female on an egg mass, female with small nymphs (first to third instar), female with large nymphs (fourth to fifth instar) and female with teneral adults on 45 Lysiloma latisiliquum Benth. trees in a total population of several hundred L. latisiquum trees on Key Largo, Florida, USA. The site had been colonized by U. crassicornis for at least five years prior to this study. The U. crassicornis moved extensively among the monitored trees with over 90% of trees experiencing a change of status from colonized to abandoned or the reverse. The average length of a colonized period and an abandonment period were the same at about three months or approximately one U. crassicornis life cycle. On average the treehopper population colonized a tree for a generation and then abandoned it for a generation before colonizing it again. The number of male treehoppers on a tree was significantly correlated with both the number of aggregations of teneral adults (= unmated females), and the number of solitary females on the tree. The treehopper population functioned like a metapopulation moving among individual trees. This movement allows the insect to maintain a population at a site with acceptable host plants without negatively affecting future generations, while also providing dispersing individuals to seek and colonize new host resources and provide new genetic material to other colonized populations of host plants.