Abstract: The aim of this study was to record the population and the fluctuations of Tingis sideritis Š tus á k, on a wild population of Sideritis scardica Griseb. of mount Vermion, Greece. This is the first reference for the presence of T. sideritis in Greece, a new enemy of S. scardica. In year 2005, recordings of T. sideritis population started at 15 of May and lasted until 4 of July. These recordings were repeated every 10 days (6 periods in total) on 50 wild tea plants selected in random. Two branches of each wild tea plant were studied. In year 2006, recordings of T. sideritis population started at 12 of May and lasted until 1 of July (with the same procedure as in 2005). In the laboratory, the insects of each branch were measured under a stereoscope and total replications were 100 (50 plants X2 branches). Period of recordings x year interaction found statistically significant at p<0.001. In general, year 2006 showed lower total number of adult insects in comparison to year 2005, may be due to the presence of natural enemies of T. sideritis, but most important is the different population fluctuations between the two years and it seems to be a common biological phenomenon in insects. If we take in consideration that a Sideritis plant may possess about 9-10 branches, then we can find about 100 adult insects/plant.
INTRODUCTION
S. scardica Griseb. (Lamiaceae), is the wild mountain tea of Greece, usually found in mountain Olympos and in some other mountains of Greece such as Taygetos, Paikon, Voras, Vermion etc. In general, genus Sideritis sp. has no serious enemies. The most common enemy found in South-Eastern Europe is T. sideritis Štusák, 1973 (Heteroptera, Tingidae). T. sideritis sp., was found for the first time in Bulgaria on S. montana L. (basic host-plant) and later on S. comosa Stank (Štusák, 1973). Little is known about T. sideritis, a grayish brown with dark spots insect of the family Tingidae, usually dimorphic (macropterous and brachypterous) with blackish armed head (Štusák, 1973), a bug of the family Tingidae with many other species that are enemies in various cultivations (Drake and Ruhoff, 1965; Štusák, 1974). Generally, there are not references of great damages on Sideritis sp. Most important are considered the immature stages of these bugs and thus many studies have been conducted in the past (Mathur, 1955; Maa, 1957; Štusák, 1968, 1973, 1974). Sideritis has many species but all can been distinguished by proper keys of recognition (Wetmore, 1996).
The aim of this study was to record the population and the fluctuation of T. sideritis on wild population of S. scardica of mount Vermion, Greece. This is the first reference for the presence of T. sideritis in Greece, a new enemy of S. scardica.
MATERIALS AND METHODS
After many years (2000-2006) of monitoring various insects on wild species, the laboratory of Entomology of the Technological Education Institution of W. Macedonia/Branch of Florina, Department of Plant Production, discovered T. sideritis on mount Vermion in Greece in 2005. In the region of Servia, Kozani (on mount Vermion) a population of wild mountain tea (S. scardica) was selected for the study of T. sideritis. The study was conducted in years 2005 and 2006 at an altitude of 650 m and the total area covered by the wild mountain tea population was nearly 0.4 ha. In year 2005, recordings of T. sideritis population started at 15 of May and lasted until 4 of July. These recordings were repeated every 10 days (6 periods in total) on 50 wild tea plants selected in random. Two branches of each wild tea plant were studied. In year 2006, recordings of T. sideritis population started at 12 of May and lasted until 1 of July (with the same procedure as in 2005). In the laboratory, the branches were shaken by a small vibrator and the insects were collected on a membrane. Then the insects of each branch were measured under a stereoscope and total replications were 100 (50 plants X 2 branches). Afterwards these insects were killed in a small glass bottle (6x2.5 cm) filled with pure alcohol. The genus recognition was easy according to earlier studies (Štusák, 1974) but species T. sideritis was specified by the Department of Entomology at the National History Museum, London-England, from specimens sent for this purpose. ANOVA was based on two factors: the year (2005 and 2006) and the period of the recordings (6 in each year). Transformation of data and ANOVA were based on the procedures described by Snedecor and Cochran (1980) as they were utilized in previous studies on different insect species by Deligeorgidis and Ipsilandis (2004) and Deligeorgidis et al. (2007). Original data are reported in tables.
RESULTS AND DISCUSSION
Figure 1 shows the adult insect T. sideritis present
in Greece, identified by the Department of Entomology at the National History
Museum, London-England, about 2 mm long and usually brachypterous.
| Fig. 1: | Tingis sideritis, adult insect, brachypterous (First reference in Greece, adaptation from our observations) |
| Table 1: | Mean number of adult insects (T. sideritis) at each period of recording (6 periods), for the two years (2005 and 2006) and mean of the years (period x year interaction found statistically significant at p<0.001) |
| Fig. 2: | Population fluctuation across the six periods of recordings for the two years (2005 = upper line and 2006 = lower line) |
Table 1, shows original data from the two years (2005 and 2006). Mean number of adult insects (T. sideritis) from the selected 100 branches at each period of recording (6 periods) within each year are included and additionally, the mean of the years (period x year interaction found statistically significant at p<0.001). In year 2005 there were found 4.61-12.17 adult insects/branch, while in 2006 about 5.12-11.01 adult insects/branch. Figure 2 shows population fluctuation across the six periods of recordings for the two years (2005 and 2006). It is obvious that, the two years had a different total number of adult insects and a different distribution across the periods of recordings. In general, year 2006 showed lower total number of adult insects in comparison to year 2005, may be due to the presence of natural enemies of T. sideritis, such as some birds or a few mites (A.C. Bent and P.N.
Deligeorgidis, unpublished data), but most important is the different
population fluctuation between the two years and it seems to be a common
biological phenomenon in insects (Deligeorgidis et al., 2007).
Year conditions are an important parameter for the development of insects
and this was obvious because of the interaction with the period of recordings,
where there was found a different population density for the two years.
In year 2005 there was an increasing insect population until the sixth
period of recording where started the decreasing period (in early July),
possibly due to a renewal of insect population (a new generation) and
the maturity of host plants of Sideritis, which become harder.
A part of the population may migrate to other host plants. Up to now,
only S. montana L., S. comosa (Rochel) Stank and S. taurica
Steph are referred as host plants of T. sideritis (Štusák,
1973), but S. scardica Griseb., S. athoa Papan. and Kokkini
and other wild species may included too, according to our newer observations
on Greek Sideritis species. In year 2006 there were two phases
of decreasing population: in the fourth and sixth period of recording.
The first phase of decreasing may be due to an extensive renewal of population
in relation to the lack of abundance of food, for this specific year.
If we take in consideration that a Sideritis plant may possess
about 9-10 branches (Goliaris and Roupakias, 1997, 1998), then we can
find about 100 adult insects/plant.
| Fig. 3: | Possible distribution of Tingis sideritis in South-Eastern Europe (Greece, Bulgaria, FYROM) |
Figure 3 presents possible distribution of T. sideritis in South-Eastern Europe (Greece, Bulgaria, FYROM) according to present study and previous data (Štusák, 1973, 1974; Périkart, 1983; Périkart and Golub, 1996). Monitoring of this species will continue because of the importance that may have for the productivity of S. scardica.