Collection and preservation of leafhoppers
More than 3,000 bulk samples of sap-feeding hemipteran insects were
obtained between 1998-2018 through field work by the last author, his
students and colleagues during surveys that aimed to document poorly
studied insect faunas in various parts of the world and to obtain
representatives of all major lineages of Cicadellidae for use in
phylogenetic and systematic studies. This material was supplemented by
the first author’s collections in Europe between 2001-2018. Specimens
were collected using various methods including sweeping and vacuuming of
vegetation, night collecting at lights, and in Malaise (flight
intercept) traps. Specimens were collected directly into 95% ethanol in
the field, returned to the laboratory and stored in -20ºC freezers at
the INHS. Voucher specimens were also pinned for species identification
and reference. Some samples included undescribed species from
under-investigated areas, and they are waiting to be described in the
context of other projects. In 2018, screening was carried out on a
subset of 227 samples from independent sampling events in 28 countries
(six continents) worldwide (Argentina, Australia, Bolivia, Brazil,
Cameroon, Chile, China, Czech Republic, Ecuador, French Guiana, Ghana,
Kyrgyzstan, India, Italy, Madagascar, Mongolia, Nicaragua, Papua New
Guinea, Peru, Republic of Congo, Serbia, South Africa, Swaziland,
Switzerland, Taiwan, Thailand, United States, Zambia). The land cover of
the sampling events was analyzed using thematic maps within a geographic
information system (QGIS 3.8, 2019) (Figure 1). Although 98% of the
collections were intentionally obtained from natural areas or patches of
native vegetation within more anthropogenic landscapes, we evaluated the
land cover of a larger area including each sampling site using the
raster layer Cropland and Pasture area (resolution 10 x 10 Km)
(Ramankutty et al., 2008).
In total, the 227 samples encompassed about 1,000 specimens, with each
species (or morphospecies) represented by 1 to 20 specimens belonging to
the phloem-feeding leafhopper subfamily Deltocephalinae (except 1 sample
belonging to the related hemipteran family Membracidae), which includes
most of the previously documented vectors of phytoplasmas (Table S1). At
least one specimen from each sample was selected randomly (with
preference for males when present because species identification usually
requires examination of male genitalia) for the molecular analyses.