Deltocephalinae, and Typhlocybinae. Most species of
the subfamily Agallinae, which in Costa Rica consists
of six genera and more than 60 species (Nielson and
Godoy 1995), occur in the lowlands. In the largest
genus, Agalliopsis, 14 of the 35 species (40%) are
known from intermediate altitudes, 14 species (40%)
are restricted to the lowlands, and 7 (20%) to higher
altitudes. Two small subfamilies of leafhoppers
(Nioninae and Tinterominae) have never been col-
lected in the lowlands.
Species in most subfamilies feed primarily on
phloem, but Cicadellinae feed on xylem sap and
Typhlocybinae feed on cell contents of the meso-
phyll. Nymphal leafhoppers are usually more host-
specific than adults, and the host plant on which a
species reproduces can be determined only by rearing
nymphs to the adult stage. Species identification re-
lies principally on characters in the genitalia of the
adult male, so nymphs cannot be readily identified.
Unlike many treehoppers, adult leafhoppers rarely
show parental care and are not normally found to-
gether with nymphs, excluding this as a shortcut to host
plant identification. Little is known about the host
plants of tropical leafhoppers.4.3.4. Sex and Social Life
of Umbonia Treehoppers
Karen Masters
Best known for their bewildering body shapes, treehop-
pers (Membracidae) are intriguing for ecologists inter-
ested in variable sociality and mating strategies. Dispar-
ate behaviors can be found even among closely related
species, such as Umbonia ataliba and U. crassicornis,
whose biologies reveal how ecological pressures and
population genetic histories influence patterns of mater-
nal investment, sex allocation, and mating behavior.
Adults of Umbonia ataliba and U. crassicornis have
thornlike bodies and are noteworthy for their pre-
social tendencies (Fig. 4.5). In both species, siblingsFigure 4.5. Umbonia treehoppers on stem.
Photograph by Dan Perlman.103 Insects and Spiders