One of the authors (OK) and Mr. A. Selin (Tallinn, Estonia) from the Estonian Lepidopterists' Society collected the material during their entomological expedition in Uzbekistan, on a southern flank of the Chatkal Range of the Western Tien Shan Mountain system. The collecting methods included light trapping and selective sampling near light traps. The light trapping site was at the main building of the Chatkal National Reserve (IUCN category IV) at about 1100 m elevation. The lamps were placed within bush and shrub vegetation, with steppe slopes behind (Fig. 1.)

Figure 1.  

Sampling site landscape in Chatkal NR.

The Chatkal NR covers about 3500 km² of the forest and alpine biota on the southern slopes of the West Tien Shan range (Zhumanova et al. 2021). The steppe and mountain steppe pastures on lowland and lower elevations around the National Reserve are over-grazed and the grazing stresses the Reserve.

Palpi, antennae, legs and details of the venation of wings were measured on mounted specimens using an ocular micrometer and binocular microscopes, under 40× magnification. The genital slides of males and females were treated using established procedures (Hardwick 1950), inspected in glycerol, embedded in Euparal and, thereafter, photographed from the ventral view. Moths were photographed prior to investigation of the genital structures using a Canon 300D digital camera, while the genital slides were photographed by a Leica DFC295 camera attached to a Leica S6D stereomicroscope. The obtained photographs were augmented using Adobe Photoshop Elements v. 7 in order to clarify their resolution.

Our discovery of the second species of Pljushtchia north of the Ferghana Valley, in the Chatkal National Reserve, significantly expands the known distribution area of the so far monotypic genus. The type species—P. prima—has been collected together with such endemics of Hissar Range as the species of Phthorarcha Meyrick, Ramiria Viidalepp and others, which are consuming wild apple leaves. The Tajikistanian pests of fruit trees were investigated by Degtjareva (1973). The food plant association with wild apple trees (Malus sieversii, M. hissarica, M. turkestanica) and the occurrence in relic fruit tree forest sites, suggest the possibility of co-evolution of Pljushtchia (and also Phthorarcha spp., Ramitia spp.) moths with wild apple trees. The origin (Wang et al. 2018), evolutionary history (Spengler 2019), phylogeny (Harris et al. 2002) and distribution of wild fruit trees has intrigued arborists, gardeners and taxonomists and are rather well studied (Yousefzadeh et al. 2019 and references therein). The divergence time of ancestors of Malus and Pyrus from the ancestral Rosales is dated as during the Eocene epoch (Wang et al. 2018). According to Wang et al. (2018), Yousefzadeh et al. (2019) and Brookfield (2000), the distribution of Malus sieversii (the ancestor of Malus domestica) out of the Ili Region, along the northern coast of Tethys Sea, to North Iran and Europe, occurred during the Miocene epoch. Since then, Malus sieversii has radiated southwards as Malus turkestanica and Malus hissarica.

It seems not usual that the same moth species inhabits mountain forests north and south of the western part of the Fergana Valley. This problem needs a special study. The fauna of Tien Shan is fragmentarily known – just the hotspots around Almaty and in the westernmost parts of the huge mountain ridge are sufficiently studied (see Viidalepp (1988) for a brief review). Gorbunov (2011) has published a review of moths of Kazakhstan, including Geometridae.

The fauna of desert, steppe and arable areas surrounds both Tien Shan and Hissar from the West: as an example, rose-feeding Cidaria fulvata Forster reaches the 1500 m elevation in Tien Shan and 1800 m elevation on the southern flank of Hissar Mountains. The fauna of alpine meadows does not differ between these ridges as suggested by the spatial distribution of the genera Stamnodes Guenėe, Grumia Staudinger and Nychiodes Lederer (Viidalepp 1988). Phthorarcha ishkovi Viidalepp is an apple tree pest in Tien Shan, whereas other species of this genus are pests in Fergana Valley and Hissar orchards (Degtjareva 1973). The green coloured moth Chlorissa arkitensis Viidalepp, occurs in Western Tien Shan and Degtjareva (1973) lists the vicarious C. gigantaria (Staudinger) (as C. pretiosaria Staudinger) for orchards of the Hissar. Some Artemidora Meyrick species (A. maracandaria Erschov, A. alpherakyi Wagner) are common in both mountain systems at 1000-3000 m elevation, while A. metsaviiri Viidalepp and A. ardea Weisert do not reach Tien Shan in their distribution. The Artemidora larvae are feeding on Rosacea (Degtjareva 1973). Old mountains of Tien Shan with the Hissar Range (Brookfield (2000), Allan et al. 2021), connected by the Alay Range, are discussed from the Permian epoch on the northern coast of the Tethys Sea (Sinitsyn 1962), whereas the insular Pamir and Tibet blocks are mentioned since the Triassic (Burtman 2010) and have accreted Asia later, as well as parts of China. Subtropical forests covered the mainland in the Tertiary (Wang et al. 2018). The flora and fauna of these old mountains are rich in endemic taxa compared to that of Pamir (Raduła et al. 2021), which was uplifted in the Holocene after collision of the block of Hindostan with Asia (Tong 1994, Yin 1994i). The tertiary subtropical forests are pushed from lowland to the montane belt due the Holocene climate gradual cooling and drying (Bruch and Zhilin 2007, Zhumanova et al. 2021). The recent climate change accelerates the extinction of tertiary relics of fauna and flora (Aizen et al. 1997). The westernmost Tien Shan has its own genus-level endemics as Tshimganitia Wehrli and Ratsa Viidalepp & Kostjuk, whereas the genus Hissarica Viidalepp seems restricted to the southern Hissar Range.