Jumping plant lice (Hemiptera, Psylloidea) in rest stops of Hungarian highways

In the framework of a survey of arthropods in rest stops of Hungarian highways, 19 species of jumping plant lice were collected. Three species belong to the family Aphalaridae, one to Calophyidae, two to Liviidae, nine to Psyllidae and four to Triozidae. Two species ( Livilla variegata and Trioza neglecta ) are alien, non-indigenous species; the others are native to Hungary. The most abundant species were Calophya rhois , Cacopsylla melanoneura and Trioza neglecta . The specimens of C . melanoneura were found in 20, T. neglecta in 10 and C. rhois in 6 localities out of the 31 rest stops surveyed.


INTRODUCTION
The eminent role of roads and highways in the expansion of introduced species is well known ( Camprag, 2002;Fokin, 2006;Gilbert et al., 2004;Horv ath and Benedek, 1986). Invasive pests can be transported for several hundreds of kilometres from their original habitats by vehicles to colonise far and new habitats. On the other hand, protective zones of highways can also be considered as green corridors in agricultural landscapes and these corridors may serve also as refuges for native insects. In the last few years numerous papers have been published on the invertebrates inhabiting highway rest stops in Hungary, including also discoveries of several new alien and invasive agricultural pests (e.g. Basky, 2015;Bayoumy et al., 2011;Kiss et al., 2013Kiss et al., , 2016Kontsch an and Kiss, 2015;Kontsch an et al., 2015;Koz ar, 2009;Koz ar et al., 2013;Lengyel et al., 2015;Podluss any et al., 2014;Szentesi et al., 2017;Vona-T uri et al., 2017Vona-T uri et al., , 2019. The jumping plant lice or psyllids (Hemiptera, Psylloidea) are a group of phytophagous insects with numerous economically important and invasive species. So far more than 70 jumping plant louse species have been reported from Hungary (Kontsch an and , but several species have been found only rarely or were recorded only at the end of the 19th century (Ripka, 2008). A systematic survey of the insect fauna in rest stops (service areas) of Hungarian highways was carried out in the 2010s to evaluate the importance of these habitats in the spread of invasive species. Jumping plant lice were not a focal group of the study; however, numerous specimens of the superfamily were collected. These records are summarized in the present work.

MATERIAL AND METHODS
The faunistic survey was organized on 31 rest stops of five highways in Hungary (Fig. 1). The rest stops formed two transects in the country (M1, M3, M5, M7) and a half-circle (M0) around the capital, Budapest. Adult jumping plant lice were collected by two methods: branch-beating and Fig. 1. The collection sites on the highways in Hungary suction sampling. In the case of the branch-beating method, 20 branches of five plant species were beaten in each rest stops with a stick and falling insects were collected into a large umbrella, thus the plant species from which the specimens were collected were known. The suction sampling was carried out using a hand-hold leaf blower (see Samu and S arospataki, 1995), referred to in the followings as D-VAC. In this case, samples were taken from leaf litter and sward, and the source plants were not identified. The collected insect material was transferred into plastic bags, stored in a deep freezer, later sorted into different insect groups and the specimens were preserved in 75% alcohol. For identification, we used books of Ossiannilsson (1992) and Hodkinson and Hollis (1987), and the presented system followed Burckhardt et al. (2021). The jumping plant lice were cleared in hot lactic acid and examined on a cavity slide under a compound microscope. After identification, the specimens were placed back in alcohol and deposited in the Plant Protection Institute, Centre for Agricultural Research, Budapest, Hungary.

RESULTS
Altogether 19 species of jumping plant lice were collected in the study. The species belonged to five families, Aphalaridae, Calophyidae, Liviidae, Psyllidae and Triozidae. The highest number of species were found along the highway M3 (10 species), eight species were collected on M1, seven on M7, six on M0 and only three on M5. There were important differences among the species numbers in the rest stops. Only one species was collected at the majority of the collection sites, and the highest species number per site was five (Fig. 2).

DISCUSSION
In the framework of our survey on Hungarian highways, 19 species of jumping plant lice were collected. Three of them belong to family Aphalaridae, one to Calophyidae, two to Liviidae, nine to Psyllidae and four to Triozidae. Two species (Livilla variegata and Trioza neglecta) are alien, non-indigenous species, while all the others are native to Hungary (Ripka, 2008). Regarding the species numbers of the psylloid families of Hungary (Ripka, 2008), the triozids with four reported species seem to be underrepresented compared with the other families. Jumping plant lice were collected at 30 localities from the 31 sites surveyed in total. Cacopsylla melanoneura, oligophagous mainly on Crataegus and Malus spp., was the most frequent species in the highway rest areas; it was found in 20 localities and was collected on more than 20 different plant species, most of which represented shelter or casual plants, not the host plants (according to the definition by Burckhardt et al., 2014). This species is very common in Hungary (Ripka, 2008;Kontsch an et al., 2020). The alien T. neglecta, monophagous on Elaeagnus angustifolia, was found at 10 sites. Beside its host plant, this jumping plant louse was collected on eight other plant species. The host plants of T. neglecta are frequently planted in the rest stops, which is one of the reasons for its numerous occurrences. In contrast with the frequent occurrences in the highway rest stops, this species has been only rarely collected in Hungary before . Calophya rhois, monophagous on the smoke tree or smoke bush (Cotinus coggygria), was collected at six sites in the framework of the study. Beside its known host plant, C. rhois was also found on 10 other plant species, which should be considered as casual records; C. rhois generally reaches high abundances on its host, and its dispersing adults can be caught also on plants in close vicinity. The smoke tree is frequently planted in highway verges and rest stops, which explains the widespread occurrence of C. rhois at the surveyed sites. Widespread in the Mediterranean, C. rhois is considered as a native species also in Hungary, similarly to smoke tree, which can be found in natural environments in the mountainous area of the country . It should be noticed that C. rhois was mentioned as an alien species for Serbia (Jerini c-Prodanovi c, 2012), but this probably reflects only a different use of terminology, and the status of the species is perhaps identical in the two neighboring countries. The other jumping plant louse species were usually collected less frequently, at 1-5 different sites.
Noteworthy are also the records of another introduced species, Livilla variegata, monophagous on Laburnum spp., which was collected at two sites, where its known host plants were not recorded. Maybe this species arrived from the outside area of investigated rest stops of the highways and it was only a transient guest species in these habitats. This species has been scarcely found in Hungary, recorded only from Budapest (Ripka, 2008).
Three species with well-known economic importance (Cacopsylla pruni, C. pyri and C. pyrisuga) were also found at the rest stops of the highways, but in a very small number of specimens (1-2) and only at some localities (Figs 5-6), although their host plants (pear trees and blackthorn) are frequent native plants, planted also on the rest stops and in their surroundings.
Our study highlights the fact that psyllids have been only poorly studied in Hungary. Several species only scarcely recorded in the literature can be frequently found during systematic surveys even in artificial habitats, like highway verges.