treehoppers.insectmuseum.orgTreehoppers: Aetalionidae, Melizoderidae, and Membracidae (Hemiptera)

Treehoppers Aetalionidae, Melizoderidae, and Membracidae (Hemiptera) Introduction Search Taxa Higher Taxa Genera Keys Top Pics Sounds Distribution References Links News Search Taxa: help for all Taxa ( Enter a taxon, select among the results, click "Go" ) • Explore taxonomic diversity among HIGHER TAXA • Identify treehoppers via KEYS • Discover generic and species richness through GENERA • Find LITERATURE • List genera by place via DISTRIBUTION (in preparation) • Visit LINKS • Tour CYBERMUSEUM (in preparation) • Hear treehopper SOUNDS • View gallery of TOP PICS • Submit photos, comments, corrections, or questions • Check NEWS • Learn more about treehoppers – see OVERVIEW, below Introduction TREEHOPPERS provides online access to unique bibliographic and taxonomic resources for retrieving information on the insect families Aetalionidae, Melizoderidae, and Membracidae, collectively known as treehoppers. The dazzling array of treehopper body shapes and behaviors invite us to imagine, explore, question, and discover. The mission of the TREEHOPPERS website and database is to support these lofty pursuits among students, teachers, researchers, and the general public. Overview of Treehoppers Treehoppers make up a group of more than 3500 described species of plant-feeding insects in the order Hemiptera. Of the three treehopper families, Membracidae is by far the most diverse (428 genera and more than 3450 species), followed by Aetalionidae (6 genera, 42 species), and Melizoderidae (2 genera, 8 species). Recent phylogenetic analyses suggest treehoppers form a monophyletic lineage, as yet unnamed, related to leafhoppers, within the superfamily Membracoidea. Treehoppers are found in all major zoogeographic regions of the world. Europe has relatively few species, and Madagascar and New Zealand have no known indigenous species. Aetalionidae The family Aetalionidae is primarily Neotropical, but the subfamily Aetalioninae includes the New World genus Aetalion recorded from the Nearctic (Arizona and Florida) and Neotropical regions, and the Old World genus Darthula of the Indomalayan region. All members of the second aetalionid subfamily, Biturritiinae, occur only in the Neotropical region. Illustrated here are the genera Aetalion (left: Aetalionidae: Aetalioninae: Aetalionini) and Lophyraspis (right: Aetalionidae: Biturritiinae: Biturritiini) (both images Copyright © 2006, by Christopher H. Dietrich). Melizoderidae The smallest family of treehoppers is Melizoderidae, known only from Chile and Argentina. This group includes only two genera Melizoderes (left; Copyright © 2003, by Matthew S. Wallace & Lewis L. Deitz) and Llanquihuea (right; Copyright © 1985, by Lewis L. Deitz)both belonging to the subfamily Melizoderinae and tribe Melizoderini. Membracidae Membracidae, the largest and most widespread treehopper family, has 9 subfamilies: Centronodinae, Centrotinae, Darninae, Endoiastinae, Heternotinae, Membracinae, Nicomiinae, Smiliinae, and Stegaspidinae. Although eight of the subfamilies are restricted to the New World, one Nearctic species of Stictocephala ( S. bisonia ) is introduced and widespread in the Palearctic. The largest subfamily, Centrotinae, has 6 New World tribes and 17 Old World tribes. Shown here are an Afrotropical species, Monocentrus fuscoflavus Boulard (left; Membracidae: Centrotinae: Centrotini; Copyright © 2003, by Michel Boulard), and a Nearctic species, Telamona maculata Van Duzee (right: Membracidae: Smiliinae: Smiliini; Copyright © 2003, by Matthew S. Wallace & Lewis L. Deitz). Morphological, Behavioral, and Ecological Diversity For many, but not all treehoppers, the most prominent feature is an oddly-shaped pronotum. Although once placed in a single genus, the three bizarre species illustrated here actually represent three unrelated membracid subfamilies (1, Stegaspidinae; 2, Heteronotinae; and 3, Membracinae; plate 25, Duncan 1843a, Homoptera, in Introduction to Entomology). Less obvious is the presence of three or fewer longitudinal rows of enlarged setae (cucullate) on the tibia of the hind leg. In nearly all adults of the family Membracidae (2-24 mm in length) the pronotum is noticeably enlarged and extends posteriorly over the scutellum. Also, in membracid males, distinct lateral plates are differentiated from abdominal tergum IX, and, in nymphs (many of which have dorsal spines), abdominal segment IX forms an unbroken sheath around segment X. Melizoderid adults (4-6 mm in length) have an anterior pronotal horn, but the posterior pronotal process (characteristic of most membracids) is absent, so the melizoderid scutellum is fully visible. In melizoderid nymphs abdominal tergum IX completely conceals the anal orifice dorsally. Aetalionids (3-30 mm) may have various modifications of the head (simple or with a pair of dorsal horns), pronotum (simple or with a middorsal process), or scutellum (fully visible and either simple or with an elevated keel). Also, in aetalionids the prothoracic trochanter and femur are fused, and females have abdominal tergum IX produced posteroventrally. Treehoppers are recorded from many herbaceous and woody host plants representing more than 100 plant families. Polyphagy is widespread among tropical treehoppers, but many Nearctic species are found on a single host genus or family. Among insects, treehoppers have an unusual array of behaviors and ecological interactions. Using vibrational songs transmitted through their host plants, they are able to communicate alarm, discovery, and courtship signals. As a by-product of ingesting large quantities of plant sap (phloem), treehoppers secrete a sugary substance called "honeydew", which serves as food for a variety of opportunistic ants, bees, and wasps. Thus, treehoppers frequently benefit from interactions with ants that provide "house cleaning" services and sometimes protect the hoppers from predators in exchange for the honeydew secretions. While some species are solitary, many treehoppers are gregarious or subsocial, and may even guard their eggs and immatures. Both parental care and ant mutualism are common among aetalionids as well as membracids. Aetalionids and some membracids deposit egg masses on the surface of plants. Most membracids, however, insert the eggs into plant tissue; in so doing, a few species injure their hosts so seriously that they are considered pests. Treehoppers as Models for Research and Discovery The diverse morphological, behavioral, ecological, and distributional patterns among treehoppers make them an ideal group for exploring evolutionary relationships and the connections among form, function, genetics, the environment, and biogeography. The use of treehoppers as model organisms in evolutionary biology is ever increasing as evidenced by research in such areas as sympatric evolution, acoustic communication, host plant associations, biogeography, behavior, and evo-devo biology. Recent phylogenetic studies are helping to unravel patterns in behavior and biogeography. For example, morphology-based analyses suggest that all Old World membracids (17 tribes) arose from two separate colonizations from the New World. These accidental colonizations set the stage for tantalizing natural” experiments in evolution, running over millions of years, wherein treehopper lineages on opposite sides of the planet would radiate into parallel niches. This grand experiment, both spatially and temporally, brings to mind countless questions about key morphological and life history traits that may be addressed by comparing various attributes among Old and New World treehopper faunas. Treehoppers are significant components of many ecosystems around the world. Distributional patterns among living treehoppers reveal hot spots of diversity that merit diligent study by those concerned with preserving global biodiversity. Within the Nearctic region, Arizona stands out as a treehopper hot spot, and on a global scale, Mexico, Brazil, the Caribbean, Australia,...