Abstract: Butterflies are the best taxonomically studied groups of insects and are also good indicators of environmental changes. Because of their diversity, wide distribution, specificity to vegetation type, rapid response to perturbation, taxonomic tractability, statistically significant abundance and ease of sampling, they have been considered useful organisms to monitor environmental changes. The present work is result of a survey on butterfly fauna of Sawanga-Vithoba Lake region. For the observations of the species transect of 1 km long and 5 m wide was followed. Butterflies were primarily identified directly in the field or, following photography. Study was carried out for one year. Total 28 species of butterfly at Sawanga Vithoba lake area under five different families were observed. Most of the species were common. Two rare species were observed in this region. Butterfly exhibits seasonal variation in distribution of species at four stations of Sawanga Vithoba lake. In monsoon total number of species was more than in winter and summer. Few species of butterfly such as Papilio machaon (Linnaeus), Parnara guttata (Brener and Grey). Cepora nerissa (Fabricius), Pieris brassicae (Linnaeus), Junonia almana (Linnaeus), Junonia lemonias (Linnaeus), Phalanta phalantha (Drury) and Acraea terpsicore were not observed in summer. Much similar species of butterfly are observed at four stations of Sawanga Vithoba Lake area. Species richness of few species such as Catochrysops strabo, Eurema hecabe (Linnaeus), Pseudozizeeria maha (Kollar) is higher in all the seasons. Family Nymphalidae is the most represented family at Sawanga Vithoba lake region district Amravati.
INTRODUCTION
There are around 1.4 million species on earth out of which around 53% are insects (Hassan, 1994). Approximately 17,200 species of butterfly have been reported world wide and of which around 1,501 species reside in India (Kunte, 2000). Around 351 and 334 species in Peninsular India and the Western Ghats (Tiple, 2011) and around 177 species in Madhya Pradesh and Vidarbha of central India are found (D’Abreu, 1931). Butterflies are recognized for their beauty and grace (Rafi et al., 2000). They are well studied due to their diurnal behaviour, marvelous shapes, bright colours and graceful flight (Javaid, 1978). They are the pollinators and indicator of environmental changes. They possess great aesthetic and commercial values (Ahsan and Javaid, 1975). Taxonomy of the butterflies are also well studied (Robbins and Opler, 1997). Butterflies are sensitive to habitat degradation and climate changes and thus good indicators of environmental changes (Kunte, 2000).
Butterflies are one of the important food chain components. They serve themselves as a food for the birds, spiders, reptiles and predatory insects. Butterflies and moths (order Lepidoptera) can be used as an indicators in the study of population and community ecology (Pollard, 1991).
Butterflies are diverse animals and are widely distributed. They are very specific to vegetation type and respond rapidly to perturbation. Their abundance, diversity, ease of sampling made them successful and useful organisms to check changes in environmental parameters. They exhibit seasonality (Kunte, 2000). Habitat destruction, fire, use of pesticides weedicides and illegal collection for trade reduced the diversity of butterfly fauna.
Diversity, richness and abundance of the butterfly fauna of Sawanga-Vithoba Lake region is presented in the current study. This study can be used as a baseline for the future studies of diversity patterns at Sawanga-Vithoba Lake region.
MATERIALS AND METHODS
The findings presented here are based on a bi-weekly survey carried out from June 2011 to May 2012 at the Sawanga-Vithoba lake region. Sawanga-Vithoba lake is also known as Malkhed Prakalpa or Malkhed Talav. The observations were made from 08:00-11:00 am, which is a peak time for butterfly activities. Area around the lake was divided into four stations, East, West, North and South. Each station was surveyed in the three seasons multiple times. For the observations of the species transect of 1 km long and 5 m wide was followed. Butterflies were primarily identified directly in the field or, following photography. Study was carried out for one year. For identification of the species, book by Arun Pratap Singh was referred.
Statistical analysis
Species richness: Species richness was calculated by the equation:
where, D is the species richness, S is the No. of individuals of a particular species and N is the total No. of the individuals.
Simpson’s index (λ): It is a measure of dominance therefore (1-λ) measures species diversity:
where, n is the No. of individuals or amount of each species and N is the total No. of individuals for a site.
Shannon-Weiner index (H’): It measures both richness and abundance. It was calculated by the equation:
where, n is the No. of individuals or amount of each species and N is the total No. of individuals for a site and ln is natural log of the number.
Similarity index: Similarity index was calculated by following equation:
RESULTS
Butterfly diversity: Total twenty eight species of butterfly belonging to five different families were observed at Sawanga Vithoba lake area Most of the species were common. Two rare species were observed at this region. List of the species of butterfly at sawanga vithoba region is given in Table 1.
Documentation of butterfly species: At Sawanga Vithoba lake 10 species are very common, 14 species are common while 2 species are rare and 2 species are less common. Distribution of species of butterfly at four stations of Sawanga Vithoba lake was documented as in Table 1.
Family diversity of butterfly: It was observed that five families of butterfly reside at Sawanga Lake region. Ten species of family Nymphalidae, 9 species of family Pieridae, 4 species of family Hesperiidae, 3 species of family Lycaenidae and 2 species of family Papillionidae belonging to several genera are reported. Most of the butterfly species are common or very commonly found. But few rare species such as Pelopidas conjuncta which belongs to family Hesperiidae and Papilio machaon belonging to family Papillionidae are found. Diversity of families of butterfly at Sawanga Vithoba region is depicted in Fig. 1.
Seasonal variation in diversity of butterfly at Sawanga Vithoba lake area: Seasonal variation in distribution of butterfly species at four stations of Sawanga Vithoba Lake. In monsoon total number of species observed at the Sawanga Vithoba lake area was 28 with 351 individuals. In winter total number of species was 28 with 365 individuals while in summer total number of species was 19 with 181 individual. Few species of butterfly such as Papilio machaon (Linnaeus), Parnara guttata (Brener and Grey). Cepora nerissa (Fabricius), Pieris brassicae (Linnaeus), Junonia almana (Linnaeus), Junonia lemonias (Linnaeus), Phalanta phalantha (Drury) and Acraea terpsicore were not observed in summer.
Diversity indices for distribution of butterfly in monsoon: Diversity indices show that the distribution and diversity of butterfly at four stations of Sawanga Vithoba Lake area are in good range. Similarity index (J) in the range of 0.9 stating much similar species of butterfly at four stations of Sawanga Vithoba Lake area. Table 2 shows that all the four stations reside similar type of butterfly species. Various indices of butterfly diversity are shown in Table 2.
Diversity indices for distribution of butterfly in winter: Diversity indices show that the distribution and diversity of butterfly at four stations of Sawanga Vithoba Lake area are in good range.
| Table 1: | Documentation of butterfly species at Sawanga Vithoba lake region |
| VC: Very common, C: Common, R: Rare, LC: Locally common | |
| Table 2: | Diversity indices for butterfly diversity and distribution at four stations of Sawanga Vithoba Lake area in rainy season |
Similarity index (J) in the range of 0.9 stating much similar species of butterfly at four stations of Sawanga Vithoba Lake area. Table 3 shows that all the four stations reside similar type of butterfly species. Various indices of butterfly diversity are shown in Table 3.
Species Junonia almana (Linnaeus), Junonia lemonias (Linnaeus), Phalanta phalanta (Drury), Parantica aglea (Stoll), Acraea terpsicore (Fabricius) Pieris brassicae Cepora nerissa (Fabricius) Parnara guttata (Brener and Grey) Papilio machaon (Linnaeus) were not observed in summer. Most of the species were less in number. Few species such as Catochrysops strabo (Fabricius) (20 in number) Euchrysops cnejus (Fabricius) (21 in number) Pseudozizeeria maha (Kollar) (24 in number) were noticeable.
Diversity indices for butterfly in summer: Diversity indices show that the distribution and diversity of butterfly at four stations of Sawanga Vithoba Lake area is less as compared to winter and monsoon.
| Fig. 1: | Distribution of butterfly families at Sawanga Vithoba Lake area |
Similarity index (J) in the range of 0.9 stating much similar species of butterfly at four stations of Sawanga Vithoba Lake area.
| Table 3: | Diversity indices for butterfly diversity and distribution at four stations of Sawanga Vithoba Lake area in winter |
| Table 4: | Diversity indices for butterfly diversity and distribution at four stations of Sawanga Vithoba Lake area in summer |
Table 4 shows that all the four stations reside similar type of butterfly species. Various indices of butterfly diversity are shown in Table 4.
DISCUSSION
Butterfly species composition: A total of 28 species representing from 5 families were recorded from the multiple transect area (Table 5). Nymphalidae was the dominant family with 10 species, followed by Pieridae (9), Hesperiidae (4), Lycaenidae (3) and Papilionidae (2).
The species such as Acraea terpsicore (Linnaeus), Danaus chrysippus (Linnaeus), Junonia orithya (Linnaeus), Euploea core (Cramer), Tirumala limniace (Cramer), Hypolimnas bolina (Linnaeus), Eurema brigitta (Cramer), Catopsilia pomona (Fabricius), Catopsilia pyranthe (Linnaeus), Delias eucharis (Drury), Belenois aurota (Fabricius), Eurema blanda (Boisduval), Pelopidas conjuncta (Herrich-Schaffer), Borbo cinnara (Wallace), Pseudoborbo bevani (Moore), Catochrysops strabo (Fabricius), Euchrysops cnejus (Fabricius), Pseudozizeeria maha (Kollar), Eurema hecabe (Linnaeus), Papilio polytes (Linnaeus) were recorded throughout the year.
Habitat preference and species distribution: Butterflies are sensitive to the changes in the habitat and climate which influence their distribution and abundance (Wynter-Blyth, 1957). Analysis of the status showed that at Sawanga Vithoba lake 10 species, Acraea terpsicore (Linnaeus), Euploea core (Cramer), Pieris brassicae (Linnaeus), Catopsilia pomona (Fabricius), Cepora nerissa (Fabricius), Delias eucharis (Drury), Belenois aurota (Fabricius), Pseudozizeeria maha (Kollar), Eurema hecabe (Linnaeus) and Papilio polytes (Linnaeus) are very common, 14 species Danaus chrysippus (Linnaeus), Junonia orithya (Linnaeus), Junonia almana (Linnaeus), Junonia lemonias (Linnaeus), Phalanta phalantha (Drury), Parantica aglea (Stoll), Hypolimnas bolina (Linnaeus), Eurema brigitta (Cramer), Eurema blanda (Boisduval), Parnara guttata (Brener and Grey), Borbo cinnara (Wallace), Pseudoborbo bevani (Moore), Catochrysops strabo (Fabricius), Euchrysops cnejus (Fabricius) are common while 2 species Papilio machaon (Linnaeus) and Pelopidas conjuncta (Herrich-Schaffer) are rare and 2 species Tirumala limniace (Cramer), Catopsilia pyranthe (Linnaeus) are less common. Distribution of species of butterfly at four stations of Sawanga Vithoba lake was documented as in Table 1. Pattern of species distribution of butterfly at Sawanga Vithoba Lake area in monsoon, winter and summer is shown in Fig. 2-4, respectively.
Distributions of butterfly in different seasons at study area were assessed and result revealed that 100% were randomly distributed in monsoon, 93% were randomly distributed and 7% were aggregated in winter and 95% were randomly distributed and 5% were aggregated in summer. The aggregated distribution indicated the season preference where random distribution indicates the available resource use and suitability of season to survival (Table 6-8).
This species showing typically territorial behavior of males and many features of the steno topic K-selection strategy, can safely survive dry seasons in relatively humid groves of forests or clumps of the trees near stream area (Spitzer, 1982). In dry season, some species are often endangered in open area by birds feed and some other human factors.
Seasonality and status: In the present study, the number of butterfly encountered during monsoon were 351, which increased to 365 species in winter and it were only 181 during species in summer. However some species were recorded throughout the year.
| Table 5: | Seasonal variation in butterfly species richness at Sawanga Vithoba Lake area |
| Fig. 2: | Pattern of species distribution of butterfly at Sawanga Vithoba Lake area in monsoon |
In monsoon 28 species of butterfly were identified while in winter and summer 27 and 19 species were identified respectively. Good number of vegetation of ground herbs and flowering plants makes the conditions ideal for butterfly feeding and roaming in this area. Butterfly is often observed in moist-deciduous, semi-evergreen and secondary evergreen forests mostly at the openings in the canopy where sunlight reach the ground vegetation.
| Fig. 3: | Pattern of species distribution of butterfly at Sawanga Vithoba Lake area in winter |
| Fig. 4: | Pattern of species distribution of butterfly at Sawanga Vithoba Lake area in summer |
In monsoon lots of rain over there and much amount of humidity were present in that area with good vegetation of ground herbs and flower plants. This ideal condition of environment attracts the butterfly for feeding and roaming in this area. So in monsoon there was higher number of species found. Observation of individual species was higher so variance is higher and interprets very closely (Table 6).
In winter there was good green vegetation and favorable climate condition so species were more frequent compared to the summer but the density of individual species was very less compared to the monsoon (Table 7-8).
Butterflies: Are common for only a few months and rare or absent in other parts of the year (Kunte, 2000). Table 5 represents seasonal variation in species richness of different families observed during study.
Species diversity and abundance pattern: Shannon, Simpson and Hills diversity indices were calculated for three different seasons. The Shannon diversity index indicated that winter is relatively diverse (1.355) followed by monsoon (1.350) and summer (1.162) (Table 2-4). Species were also ranked according to their abundance.
Insects are extremely important components of the bioindicators of the world (Chakaravarthy et al., 1997; Jana et al., 2009). In India work on butterfly studies was reported in Century (Wood-Mason and De-Niceville, 1887; Gaonkar, 1996a). Many scientists have worked on butterfly in different parts of the India (Fergusson, 1891; Gaonkar, 1996b; Larsen, 1989; Mathew et al., 2000; Sudheendrakumar et al., 2000; Roy et al., 2010). Indian butterflies forms one fifth of the world’s butterfly species (Kunte, 2000). About 1501 species of butterflies has been recorded from the India (Gaonkar, 1996a).
| Table 6: | Species distribution of butterfly at Sawanga Vithoba Lake area in monsoon |
| Table 7: | Species distribution of butterfly at Sawanga Vithoba Lake area in winter |
Peninsular region of India resides about 350, Western Ghats hosts around 331 species and 313 species are reported in South India (Gaonkar, 1996b), of which 42 species are endemic to South India.
Availability of wide range of altitudinal gradients, microclimatic regimes, diverse habitats makes southern part of the peninsular India rich and diverse than the other parts. There are reports of migration of butterfly in India (Williams, 1938; Bharos, 2000; Palot et al., 2002). Butterflies are important plant pollinators and can pollinate about 50 economically important plant crops (Borges et al., 2003).
| Table 8: | Probability of detection and abundance of species of butterfly at Sawanga Vithoba Lake area in summer |
Species diversity and composition of flora and fauna is greatly affected by the several manmade factors in India. Rich and diverse insect fauna is found in the tropical region but the information on the insects in natural and man made habitats are very poor, especially for the Indian region.
CONCLUSION
Total twenty eight species of butterfly belonging to five families are observed at Sawanga Vithoba lake. Most of the species were common. Two rare species were observed.
Butterfly exhibits seasonal variation in distribution of butterfly species at four stations of Sawanga Vithoba lake. In monsoon total number of species was more than in winter and summer. Few species of butterfly such as Papilio machaon (Linnaeus), Parnara guttata (Brener and Grey). Cepora nerissa (Fabricius), Pieris brassicae (Linnaeus), Junonia almana (Linnaeus), Junonia lemonias (Linnaeus) Phalanta phalanta (Drury) and Acraea terpsicore were not observed in summer.
Similarity index states much similar species of butterfly at four stations of Sawanga Vithoba Lake area.
Species richness of few species such as Catochrysops strabo (RS-1.38, W-1.51, S-1.48), Eurema hecabe (Linnaeus) (RS-1.60, W-1.51, S-1.18), Pseudozizeeria maha (Kollar) (RS-1.70, W-1.30, S-1.78) is higher in all the seasons.
Family Nymphalidae is the most represented family at Sawanga Vithoba lake region district Amravati.
ACKNOWLEDGMENT
Our special thanks to ISRO-UoP for providing us financial assistance. The authors are also thankful to The Principal Chief Conservator of Forest (PCCF), Government of Maharashtra for giving permission to conduct present study. We are thankful to BCUD, Savitribai Phule Pune University, Pune, DST-PURSE, DRDP and UGC-CAS for partial financial support.