1. INTRODUCTION
Biodiversity is the living wealth of earth and is the quintessence of
life. Diversity takes into consideration how individuals are distributed
amongst the species (Wolda, 1988; Guo et al ., 2013; Beck et
al ., 2017; Kemp et al ., 2017). India is second most populous
country in the world not just in terms of humans but also stands among
the top countries with worlds’ rich biological diversity. The Northern
hilly region of India is exceptional for its diverse floral and faunal
constitution. Himachal Pradesh (Fig I a ) with a geographical area of
55673 Km2 is a hill state of India (30.38°- 33.21°
North latitudes and 75.77°-79.07° East longitudes) comprising 12
districts (Statistical Data, 2010). Divided in to four agro-climatic
zones with altitudinal range from 350 to 7000 meters above mean sea
level (Fig I a &b) and ecosystems temperature from 0° to more than 40°
Celsius, the transforming region has low altitude evergreen forests,
subtropical fruit trees, lustrous greens and agriculture crops to
conifers and vegetables in mid and higher attitudes to smaller shrubs
temperate fruits (Singh, 2007) and very few vegetation at extreme
altitudes dry temperate zones (CES Technical Report, 2013). The
congenial atmospheric conditions favour the luxuriant growth of various
plant and animal species as well as support the largest phylum of
arthropods. Insects are one of the most significant sections of the
biological diversity of any region. These organisms can endure even the
acute and harshest of environmental conditions due to their expansive
ability of adaptation to wider range of climate (Sala et al .,
2000; Beck et al ., 2010; Lefebvre et al ., 2018; Plantet al ., 2018). Therefore, research on the various subjects of
their behaviour, environmental impact, survey, geographical distribution
and records, etc. constitute very crucial role in any study useful for
understanding their diversity alteration and conservation (Mccain, 2005;
Watkins et al ., 2006; Bässler et al ., 2009; Moscol Olivera
& Cleef , 2009; Desalegn &Beierkuhnlein, 2010; Jaramillo-Villaet al ., 2010; Shimono et al ., 2010; Nagaike, 2010).
In view of this, despite being one of the most diverse habitats of India
several insect families remain poorly studied in the state.
Cicadellidae, one of the largest insect families of order Hemiptera
distributed worldwide is one among them, containing at least 20,000
described species (Nielson, 1985). These tiny hemimetabolous insects are
generally herbivores that suck sap from the plants, trees, shrubs and
grasses etc feeding on wide range of plant fauna. Looking at
agricultural aspect, these minute insects cause harmful economical
damage to crops either by sucking the sap and making the plant extremely
weak or indirectly by transmitting pathogenic viruses and phytoplasmas
from plant to plant, which is most difficult to manage and of major
serious concern (Nielson, 1968; Klein, 2001; Redak et al ., 2004;
Weintraub and Beanland, 2006).
Being one of the megadiverse taxon with enormous species richness and
distributional limits of such a group of insects that have high economic
impact and might be undergoing species drift, extinction or mutation due
to rapidly changing environment, plant diversity, rising anthropogenic
activities, study of their diversity is of prime importance and is
required to be investigated. Therefore, our work focussed on documenting
the distribution of leafhoppers in relation to elevation gradient in
order to establish the species richness and abundance.