FIRST REPORT OFTHE OCCURRENCE OF LIVIA JUNCI (SCHRANK, 1789) (HEMIPTERA: PSYLLIDAE) ON JUNCUS FONTANESII J. GAY EX LAHARPE (JUNCACEAE) FROM PORTUGAL

“Witches’ brooms” is a disease or deformity in a plant where the natural structure of the plant is changed, i.e., a dense mass of shoots grows, usually from a single point, with the resulting structure resembling a broom. The specimens of Juncus fontanesii J. Gay ex Laharpe were collected on July 21, 2003, in Portugal (LISU 189105). We observed the larvae of the last (i.e., fifth) stadium of Livia junci (Schrank, 1789) (Hemiptera: Psyllidae). Many exuvia of the early larval stages from Livia junci were obtained from the galls. This confirmed that the parasites lived in its larval period on Juncus fontanesii. Additionally, J. fontanesii formed the galls as a result of response to feeding, similar to other representatives of the genus Juncus. Livia junci is the only representative of the genus Livia that feeds on Juncus species in the Western Palearctic area.


INTRODUCTION
Juncus fontanesii J. Gay ex Laharpe (Juncaceae) is a species occurring in southern Europe, northern Africa and western Asia, extending to Pakistan (Kirschner, 2002).The taxon is highly variable and includes four subspecies.In Europe, it grows mainly in Mediterranean humid grasslands of tall grasses and rushes, and alongside streams and in temporarily inundated places, mostly at 0-1000 m a.s.l.(Kirschner, 2002).
However, often the morphological modifications of the host plants were so serious that these specimens were wrongly classified as a species new to science.An example is Juncus viviparus Relhan, 1785, whose name later turned out to be the synonym of another rush, namely, Juncus bulbosus L. The type specimen of J. viviparus had been collected in the vicinity of Cambridge, UK, and it was obviously infected by parasites (Buchenau, 1890).Additionally, in heads of J. bulbosus f. submucronatus J. Proćków infected by Livia junci, the distinct and usually sharp dorsal mucros, which are located just below the apices of the outer perianth segments, can be completely invisible (Proćków, 2010).

MATERIALS AND METHODS
During our research on the life cycles of the host plants, i.e., representatives of the Juncaceae family, and the insects attacking them, in the gathered herbarium material we found J. fontanesii specimens with transformed shoots, so called "witches' brooms".The plants were collected on July 21, 2003,   2).Altered inflorescences were treated with water mist in order to achieve a more flexible tissue.Then we observed the larvae of Livia junci (Hemiptera: Psyllidae) inside the studied inflorescences.From the available material, nine insects were taken out, of which two were well-preserved specimens.The nomenclature of the Juncaceae family is congruent with Kirschner's work (2002), whereas the nomenclature of Livia was adapted after Ossiannilsson (1992).

RESULTS AND DISCUSSION
Within the studied herbarium sheet (LISU 189105, Figs 1-2), there were three plants in which six "witches' brooms" of various sizes were formed.From the available material, two well-preserved insect specimens were successfully labeled as larvae of the last fifth stadium of Livia junci (Fig. 3).
Unfortunately, as a result of herbarium conservation, a large part of the entomological material was damaged to a degree that made the species identification impossible.Nevertheless, the additional seven specimens were determined as belonging to the genus Livia.Moreover, many exuvia of the early larval stages from Livia junci were gained from the galls.This confirmed that the parasites lived in its larval period on Juncus fontanesii.
To date, Livia junci has not been mentioned from J. fontanesii.Therefore, this is the first report of the feeding of this parasite on this host plant species.Additionally, this taxon formed galls in response to the feeding, similar to other representatives of the genus Juncus.
According to Hodkinson and Bird (2000), Livia junci is the only representative of the genus Livia that feeds on Juncus species in the Western Palearctic area.Thus the mass occurrence of this insect can cause a decrease in the yields of different rush species (e.g., Ozophyllum section), which are usually common components of the meadow communities of various parts of Europe.Namely, in such situations the plants cannot flourish, so it is impossible to produce fruit and seeds to be spread.
Unlike most psyllids, which develop on dicotyledonous plants, the Livia junci larvae feed on different rushes (monocots) (Hodkinson, 2009).The morphological modifications of the host plants were so serious that in the past specimens were wrongly classified, even as species new to science.The direct causes of the enormous changes of the inflorescence have not been known to date, although they were always related to the presence of a Hemiptera parasite on the plants.Taking into account the character of these changes as well as the manner of feeding of the insect (pricking tissues near vascular bundles), it is suspected that L. junci is only a vector, while the factor responsible for producing galls are phytoplasma (Weitraub and Beanland, 2006), as in apple proliferation (AP) where psyllids of the genus Cacopsylla (C.picta) are vectors for AP phytoplasma and contribute considerably to the spreading of the disease (Jarausch et al., 2003).

Fig. 3 .
Fig. 3. Larva of the last V stadium of Livia junci (both sides) from Juncus fontanesii of the herbarium sheet LISU 189105.