Journal of Threatened Taxa | www.threatenedtaxa.org | 26 March 2021 | 13(3): 17950–17962

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)

https://doi.org/10.11609/jott.6596.13.3.17950-17962

#6596 | Received 21 August 2020 | Final received 03 January 2021 | Finally accepted 24 February 2021

Does the size of the butterfly enhance detection? Factors influencing butterfly detection in species inventory surveys

Anju Velayudhan ¹ , Ashokkumar Mohanarangan ², George Chandy ³ & S. Biju ⁴

^1,2,3 Center for Wildlife Studies, Kerala Veterinary and Animal Sciences University, Pookode, Wayanad, Kerala 673576, India.

⁴ Department of Livestock Production and Management, College of Veterinary and Animal Sciences, Mannuthy, Kerala 680651, India.

¹ anjuvanju95@gmail.com, ² vimalashok7@gmail.com (corresponding author), ³ chandy@kvasu.ac.in, ⁴ bijus@kvasu.ac.in

Editor: B.A. Daniel, Zoo Outreach Organisation, Coimbatore, India. Date of publication: 26 March 2021 (online & print)

Citation: Velayudhan, A., A. Mohanarangan, G. Chandy & S. Biju (2021). Does the size of the butterfly enhance detection? Factors influencing butterfly detection in species inventory surveys. Journal of Threatened Taxa 13(3): 17950–17962. https://doi.org/10.11609/jott.6596.13.3.17950-17962

Copyright: © Velayudhan et al. 2021. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

Funding: None.

Competing interests: The authors declare no competing interests.

Author details: Anju Velayudhan (AV) has completed Post-Graduation in Wildlife Studies from KVASU-Centre for Wildlife Studies, Pookode, Wayanad. She is passionate about butterflies and she has carried out studies on butterfly species inventory surveys and the life cycle of butterflies. Presently she has been preparing for higher studies. Ashokkumar Mohanarangan (MA) has completed his Masters and Doctoral degree in Wildlife biology, from AVC College, Tamil Nadu. He is passionate about wild animal population ecology and conservation. He is working as Teaching Assistant at KVASU-CWS.  George Chandy (GC) has completed masters and PhD, in Veterinary Sciences.  He is the Course Director of KVASU-Centre for Wildlife Studies and he is passionate about Wildlife Conservation and Tribal Welfare.  Biju S. (BS) has completed masters and PhD, in Veterinary Sciences. He is working as an Assistant Professor in the Department of Livestock Production and Management. 

Author contribution: MA developed the concept, formulated hypothesis and did data analysis. AV did the field data collection, conceived the idea and carried out the preliminary analysis. GC and BS supervised the work and preparation of the final manuscript. 

Acknowledgements: The authors are thankful to the chief wildlife warden for granting permission to conduct the research study in the Chimmony Wildlife Sanctuary (WL10-13885/2017 dated 23.03.2018). We thank the wildlife warden and other field staff for their support at the time of the survey.

Abstract: Butterfly species’ abundance and factors influencing butterfly detection in Chimmony Wildlife Sanctuary, Kerala was studied from April to June 2018. The survey was carried out on 15 tracks of 2-km lengths surveyed two times resulting in the sampling effort of 60km. A total of 141 species of butterflies belonging to two orders, six families and 103 genera were observed during the study, of which 15 species were recorded as endemic. The majority of butterfly species belonged to the families Nymphalidae and Lycanidae. The size of butterflies varies significantly among families with the largest butterflies recorded in Papilionidae and Nymphalidae and the smallest butterflies from Hesperidae and Lycanidae. The factors that determine butterfly detection during the count was determined using multiple regression. The number of detections had a linear relation with abundance, size, and activities of the butterflies. The model was highly significant and explained 86.9% of the variation in the detection of butterflies (F=407.8; df=3; p<0.000). Abundance had a primary influence on detection followed by the size and activities of the butterflies. Further studies on relative detectability of different species of butterflies in the diversity and abundance estimation would help in refining methods of assessment of butterflies.

Keywords: Abundance, Chimmony Wildlife Sanctuary, Hesperidae, Lepidoptera, Lycanidae, Nymphalidae.

INTRODUCTION

Butterflies are universally popular among all fauna. They are very beautiful and come in various sizes, shapes, and colours. Different patterns on their body enhance their aesthetic value (Gupta & Majumdar 2012). The Western Ghats can be classified into three biogeographical parts based on the status and distribution of butterflies. They are the southern Western Ghats, central Western Ghats and the northern Western Ghats (Gaonkar 1996). Because of high levels of species endemism, the Western Ghats is listed under 34 global biodiversity hotspots. The region is prominent among all other biodiversity hotspots (Myers et al. 2000). The butterfly fauna of the Western Ghats consists of 346 species of butterflies under six families (Bhakre & Ogle 2018).

Most of the inventory surveys were carried out by sampling through forest paths and trails without any information on the sample area (Sudheendrakumar et al. 2000; Sreekumar & Balakrishnan 2001; Aneesh et al. 2013), hence it was not possible to estimate population density. The systematic surveys using fixed width transect or using pollard walk (Isaac et al. 2011) helps to estimate the population density of butterflies with the same sampling effort by recording additional information on length and width of the area sampled. It is essential to determine the different factors that determine the detection probability. Species-wise differences in the detection probability of butterflies were reported in the studies carried out in the United Kingdom (Isaac et al. 2011).

The family Nymphalidae is the most dominant family with a high number of species. A detailed diversity study of butterflies in Chimmony Wildlife Sanctuary (CWS) has not been done yet. Previous studies reported 24 species of butterflies in the study area (George 2012). We have investigated butterfly species size and abundance influence on the detection of butterflies in inventory surveys at CWS.

METHODS

Study area

The study was conducted in Chimmony Wildlife Sanctuary, which spreads geographically within 76.417N and 10.402E and 76.560N and 10.483E in Thrissur District of Kerala State (George 2012). The sanctuary was established in the year 1984. The sanctuary consists of parts of Kodassery Reserve with an extent of 85.07km². It is bounded by Nelliampathy Reserve Forest on the east, Peechi-Vazhani Wildlife Sanctuary on the north-west, and Sholayar Reserve Forest on the south (Fig. 1). The mean annual rainfall is 3,130mm. The sanctuary has a tropical humid climate, with three distinct seasons, dry season (December–March) followed by the south-west monsoon (April–July), and north-east monsoon (August–November). Temperature varies from 38.5°C to 15.6°C during different seasons. The minimum temperature falls below 15.6°C during December. The area is also vulnerable to forest fires during the dry season. The sanctuary has more than 250 streams and six man-made waterholes. Diverse vegetation and favourable climatic conditions in the sanctuary could support many species of butterflies.

Butterfly abundance estimation

Butterfly species abundance was estimated using fixed-width transect method in CWS from April 2018 to August 2018. Totally, 15 strip transects of 2km were selected along paths with 2-m width on either side of the transect and sampled twice that resulted in the sampling effort of 60km. The surveys were conducted between 09.30h and 13.30h when the butterflies were most active. The butterflies observed in the field were photographed for further clarification and identification. Butterflies were identified using field guides (Kunte 2006; Palot 2015; Kehimkar 2016; Bhakre & Ogale 2018) and specialists were consulted in case of uncertainty in the identification of species. The butterflies were photographed using a Nikon 3100 DSLR camera with 18–50mm and 70–300 mm lens. The butterfly survey routes were marked with GPS (Fig.1).

Statistical analysis was performed by using Windows-based statistical package Microsoft Excel, PAST (Hammer et al. 2001) and SPSS. The diversity indices such as Simpson and Shannon-Wiener index of butterfly species from each habitat were analysed with the help of software PAST. Butterfly size difference among different families was tested using one-way analysis of variance (one-way ANOVA). The factors that determine the detection of butterflies, such as abundance, activities (0—resting; 1—foraging, flying, mud puddling, etc), size of butterflies were tested using multiple regression. Both response and independent variables were log-transformed due to positive skewness of data. Linearity was examined by plotting the relationship between the response variable (number of detections) and each predictor variable (abundance and size) using Lowess plot. To investigate multicollinearity between the environmental covariates, a correlation analysis was conducted before using multiple regressions to assess the relationships between the response variable and predictor variables, thereby providing valid parameter estimates and p values. The data were analyzed using SPSS Statistics 21 (IBM SPSS Inc., Chicago, Illinois, USA).

RESULTS

Totally, 141 butterfly species were documented in CWS from April to June 2020. Butterfly species composition varied among different families, with Nymphalidae and Lycanidae constituting 62%. Families such as Hesperidae, Papilionidae, and Pieridae were constituted 16.3%, 12.8%, and 8.5%, respectively. Only one species (Double-banded Judy) was recorded in the family of Riodinidae. Thus there is significant variation in the number of species recorded among different families (X²=67.3; df=5; p<0.01). The majority of butterfly species belong to Nymphalidae and Lycanidae in Chimmony Wildlife Sanctuary.

In total, 15 species are found to be endemic to the Western Ghats region (Table 1). Butterfly species such as Indian Ace, Shiva Sunbeam, Blue Oakleaf, Danaid Eggfly, Gladeye Bushbrown, Malabar Tree Nymph, Tailed Palmfly, Tamil Catseye, and Southern Birdwing are endemic species (Images 1–45). There are four species of butterflies such as Orchid Tit, Malabar Banded Swallowtail, Crimson Rose, and Danaid Eggfly listed in the Schedule I of the Indian Wildlife Protection Act (1972). In total there are 20 species of butterflies that are catalogued in the Schedules of IWPA and provide protection to the butterflies. Common Lineblue is the most abundant butterfly followed by Common Crow and Common Emigrant in CWS. There were more than 100 individuals of all these butterflies that were recorded in the study area. There were 42 species that were recorded only once during the time of the survey.

Factors that determine detection of butterflies

The size of butterflies varies among families with the largest sized butterflies recorded from Papilionidae and Nymphalidae (102.8±23mm and 70.1±20.1mm). Hesperidae (37.5mm) and Lycanidae (30.6mm) are the smallest-sized butterflies. Pieridae and Riodinidae are the medium-sized butterflies (57.7mm and 45mm, respectively). There is a significant difference in the size of butterflies among different families (F= 118.20; df= 5; p< 0.001).

The relationship between the number of detection, abundance, and size of butterflies were tested using multiple regression. The number of detection had linear relation with abundance, size, and activities of the butterflies. The model was highly significant and explained 86.9% variation in the detection of butterflies (F= 407.76; df= 3; p< 0.00; Table 2). All the three predictors had positive abundance and size positively influenced number of detections. From the standardized partial regression, it was inferred that abundance (b₁= 0.74) had the primary influence on the detections, followed by size (b₂= 0.19), and activity of the butterflies (b₃= 0.02; Fig. 2).

DISCUSSION

Composition of butterflies varied among different families. A total of 141 species of 1,986 individuals were observed from CWS. Though the study was carried out in a limited period, the number of species reported was higher than earlier reports of the study area (George 2012). The number of species recorded in the study area was more than other protected areas in Kerala; Sudheendrakumar et al. (2000) recorded 124 species at adjacent Parambikulam Tiger Reserve. A total of 71 species from Aralam WS (Sreekumar & Balakrishnan 2001) have been recorded. The results, however, are not directly comparable outside the protected areas. The number of species recorded in Kerala Agricultural University was 139 species of butterflies (Aneesh et al. 2013). The reason for comparison is the geographical proximity of KAU compass to the study area. The study area is part of the network of protected areas such as Peechi-Vazhani towards north, Sholayar Reserve Forest in the south and Parambikulam Tiger Reserve in the east. The major habitat of the study area is evergreen and moist deciduous forest. Earlier studies recorded higher species diversity and richness in the similar habitats (Sudheendrakumar et al. 2000). Thus, the contiguous forest and evergreen habitat supports higher species diversity and endemism in the study area.

Family Nymphalidae and Lycanidae represented 62% of the total. Families such as Hesperidae, Papilionidae, and Pieridae were comparatively less. They are, 16.3%, 12.8%, and 8.5%, respectively. Out of two butterflies in the family Riodinidae of Kerala and Western Ghats, one species (Double-banded Judy) was recorded from the study area during the period of study. There is a significant variation in the species composition among different families. Family Nymphalidae dominated over other families. In almost all the studies conducted in butterflies of Western Ghats (Sudheendrakumar et al. 2000; Sreekumar & Balakrishnan 2001; Aneesh et al. 2013) Nymphalidae is the family showing the maximum number of species because this is the family representing more number of species in the Western Ghats. The study area harbours 40.7% of butterfly species of Western Ghats (Bhakre & Ogle 2018).

In total there are 20 species of butterflies that are listed in various schedules of Indian Wildlife Protection Act (1972) that provide protection to these butterflies. Only 14.2% of butterflies of recorded species are protected under IWPA. Hence it is important to include all the endemic species in the IWPA and butterflies which are more charismatic, and rapidly declining species need to be listed under the schedules. Common Lineblue is the most abundant butterfly followed by Common Crow and Common Emigrant in CWS. The other species such as Common Mormon, Chocolate Pansy, Narrow-banded Blue Bottle, Blue Mormon, Tailless Lineblue, Three-spot Grass Yellow, and Great Orange Tip were recorded. Similar species composition was recorded in Parambikulam TR (Sudheendrakumar et al. 2000) and Aralam WS (Sreekumar & Balakrishnan 2001).

Factors that determine detection of butterflies

The study highlights the differences in the species detection based on size and abundance and importance of differences in detection probability of butterfly species inventory surveys. Butterfly species such as Common Lineblue, Common Crow, Common Emigrant, Common Mormon, Three-spot Grass Yellow, Narrow-banded Bluebottle, and Blue Mormon were more frequently sighted. All these species are conspicuous, larger in size, active flyers, and some species show mud-puddling behaviour as well. This could have resulted in higher abundance and detectability. Studies on butterflies have shown that detection of same species tends to vary according to habitats (Pellet et al. 2012). Further, survey technique could also influence the abundance and density estimation. Thus our preliminary examination on butterfly detectability showed the influence of size, abundance, and activities. The number of detection had a direct relation with the abundance, size, and activities of the butterflies.

The model was highly significant and explained 86.9% variation in the detection of butterflies. Both abundance and size positively influenced the number of detections. From the standardized partial regression, abundance (b₁= 0.74) had the primary influence on the detection of butterflies, followed by size (b₂= 0.19) and activity (b₃= 0.02). Similar species-wise differences in the detection of butterflies were reported in the studies carried out in the United Kingdom (Isaac et al. 2011; Pellet et al. 2012). Further investigation on the detectability of butterflies based on size, colouration, and habitats will help to estimate population size rather than species abundance.

Table 1. Butterfly species and their abundance (data sorted in descending order) recorded in Chimmony Wildlife Sanctuary.

	Family/ Common name	Species	Abundance of butterflies	IWPA -Schedule
				I	I,II	II,IV
	Hesperidae
1	Demon sp.	Notocrypta sp.	10
2	Dusky Partwing	Psolos fuligo	8
3	Water Snow Flat	Tagiades litigiosa	7
4	Chestnut Bob	Iambrix salsala luteipalpis	6
5	Golden Angle	Caprona ransonnettii	6
6	Common Banded Demon	Notocrypta paralysos mangla	5
7	Chestnut Angle	Odontoptilum angulata	4
8	Common Spotted Flat	Celaenorrhinus leucocera	3
9	Bevan’s Swift	Pseudoborbo bevani	1
10	Brown Awl	Badamia exclamationis	1
11	Common Red Eye	Matapa aria	1
12	Common Small Flat	Sarangesa dasahara dasahara	1
13	Dark Palm-dart	Telicota bambusae bambusae	1
14	Grass Demon	Udaspes folus	1
15	Indian Ace**	Halpe homolea hindu	1			1
16	Indian Dartlet	Oriens goloides	1
17	Pygmy Scrub Hopper	Aeromachus pygmaeus	1
18	Restricted Demon	Notocrypta curvifascia	1
19	Spotted Small Flat	Sarangesa purendra hopkinsi	1
20	Suffused Snow Flat	Tagiades gana silvia	1
21	Tamil Grass Dart	Taractrocera ceramas	1
22	Tricoloured Pied Flat	Coladenia indrani indra	1
23	Wax Dart	Cupitha purreea	1
	Lycaenidae
24	Common Lineblue	Prosotas nora	240
25	Tailless Lineblue	Prosotas dubiosa	60
26	Tiny Grass Blue	Zizula hylax	44
27	Common Pierrot	Castalius rosimon	29
28	Quaker	Neopithecops zalmora	29
29	Lesser Grass Blue	Zizina otis	26
30	Angled Pierrot	Caleta decidia	21
31	Monkey Puzzle	Rathinda amor	15
32	Common Imperial	Cheritra freja butleri	12
33	Yamfly	Loxura atymnus atymnus	12
34	Plains Cupid	Chilades pandava	10
35	Fluffy Tit	Zeltus amasa	9
36	Common Cerulean	Jamides celeno	8
37	Many-tailed Oakblue	Thaduka multicaudata Kanara	8			1
38	Metallic Cerulean	Jamides alecto	8
39	Common Hedge Blue	Acytolepis puspa felderi	5
40	Dark Cerulean	Jamides bochus	5
41	Banded Blue Pierrot	Discolampa ethion	3
42	Dark Pierrot	Tarucus ananda	3			1(IV)
43	Gram Blue	Euchrysops cnejus	3			1
44	Shiva Sunbeam**	Curetis siva	3
45	Dingy Lineblue	Petrelaea dana	2
46	Indian Sunbeam	Curetis thetis	2
47	Large Oakblue	Arhopala amantes	2
48	Apefly	Spalgis epeus	1
49	Common Silverline	Spindasis vulcanus	1
50	Cornelian	Deudorix epijarbas	1
51	Forget-me-not	Catochrysops Strabo	1
52	Indigo Flash	Rapala varuna	1			1
53	Lime Blue	Chilades lajus	1			1
54	Malayan	Megisba malaya	1
55	Orchid Tit	Chliaria othona	1	1
56	Plain Hedge Blue	Celastrina lavendularis lavendularis	1
57	Pointed Lineblue	Ionolyce helicon viola	1			1
58	Redspot	Zesius chrysomallus	1
59	Slate Flash	Rapala manea	1
	Nymphalidae
60	Common Crow	Euploea core	168
61	Chocolate Pansy	Junonia iphita	71
62	Tamil Yeoman	Cirrochroa thais	46
63	Clipper	Parthenos Sylvia	45			1
64	Common Four-ring	Ypthima huebneri	45
65	Common Castor	Ariadne merione	24
66	Rustic	Cupha erymanthis	21
67	Bushbrown Sp.	Mycalesis sp.	18
68	Common Evening Brown	Melanitis leda	18
69	Great Eggfly	Hypolimnas bolina	13
70	Striped Tiger	Danaus genutia	12
71	Blue Tiger	Tirumala limniace	10
72	Plain Tiger	Danaus chrysippus	10
73	Tamil Lacewing**	Cethosia nietneri	10
74	Angled Castor	Ariadne Ariadne	9
75	Blue Oakleaf**	Kallima horsfieldii	8
76	Common Nawab	Polyura athamas	8
77	Dark Blue Tiger	Tirumala septentrionis	8
78	Common Sailer	Neptis hylas	7
79	Cruiser	Vindula erota	7
80	Glassy Tiger	Parantica aglea	7
81	Lemon Pansy	Junonia lemonias	7
82	Autumn Leaf	Doleschallia bisaltide	6			1
83	Extra Lascar	Pantoporia sandaka	6
84	Tailed Palmfly**	Elymnia caudata	5
85	Commander	Moduza procris	4
86	Gladeye Bushbrown**	Mycalesis patnia	4
87	Grey Pansy	Junonia atlites	4
88	Chestnut-streaked Sailer	Neptis jumbah	3
89	Dark Evening Brown	Melanitis phedima	3
90	Dark-branded Bushbrown	Mycalesis mineus	3
91	Grey Count	Tanaecia lepidea	3			1
92	Yellow Pansy	Junonia hierta	3
93	Black Prince	Rohana parisatis	2
94	Blackvein Sergeant	Athyma ranga	2			1
95	Common Lascar	Pantoporia hordonia	2
96	Danaid Eggfly**	Hypolimnas misippus	2		1
97	Medus Bushbrown	Orsotriaena medus	2
98	Tamil Catseye**	Zipaetis saitis	2			1
99	Black Rajah	Charaxes solon	1
100	Blue Admiral	Kaniska canace	1
101	Brown King Crow	Euploea klugii	1
102	Common Five-ring	Ypthima baldus	1
103	Common Three-ring	Ypthima asterope	1
104	Double-branded Crow	Euploea Sylvester	1
105	Great Evening Brown	Melanitis zitenius	1			1
106	Malabar Tree Nymph**	Idea malabarica	1
107	Peacock Pansy	Junonia almana	1
108	Plain Tawny Rajah	Charaxes psaphon	1
109	Red-spot Duke	Dophla evelina	1			1
110	Tawny Coster	Acraea terpsicore	1
	Papilionidae
111	Common Mormon	Papilio polytes	73
112	Narrow-banded Bluebottle	Graphium teredon	65
113	Blue Mormon	Papilio polymnestor	64
114	Southern Birdwing**	Troides minos	20
115	Tailed Jay	Graphium Agamemnon	19
116	Common Jay	Graphium doson	16
117	Red Helen	Papilio helenus	15
118	Five-bar Swordtail	Graphium antiphates	11
119	Paris Peacock	Papilio paris	11
120	Malabar Raven**	Papilio dravidarum	10
121	Lime	Papilio demoleus	5
122	Malabar Rose**	Pachliopta pandiyana	5
123	Common Rose	Pachliopta aristolochiae	4
124	Malabar Banded Swallowtail**	Papilio liomedon	4	1
125	Common Mime	Papilio clytia	2
126	Spot Swordtail	Graphium nomius	2
127	Common Banded Peacock	Papilio crino	1
128	Crimson Rose	Pachliopta hector	1	1
	Pieridae
129	Common Emigrant	Catopsilia Pomona	112
130	Three-spot Grass Yellow	Eurema blanda	55
131	Common Grass Yellow	Eurema hecabe	53
132	Great Orange Tip	Hebomoia glaucippe	50
133	Nilgiri Grass Yellow**	Eurema nilgiriensis	28
134	Common Wanderer	Pareronia hippia	24
135	Common Albatross	Appias albina	22
136	One-spot Grass Yellow	Eurema andersonii	18			1
137	Lesser Gull	Cepora nadina	11			1
138	Mottled Emigrant	Catopsilia pyranthe	3
139	Psyche	Leptosia nina	3
140	Spotless Grass Yellow	Eurema laeta	1
	Riodinidae
141	Double-banded Judy	Abisara bifasciata	3

**- Endemic species

Table 2. Multiple regression to investigate the effect of factors that influence detection of butterflies in Chimmony Wildlife Sanctuary.

Independent Variable	Predictor	Coefficients ± SEM		SPRC	t	p	Model (r^2)	model (p)
Number of detections	(Constant)	-0.476	0.185		-2.572	0.011	0.869	F= 407.76; df= 3; p< 0.00
	Activity	0.017	0.05	0.01	0.346	0.729
	Abundance (log)	0.738	0.023	0.908	32.295	0.000
	Size of butterflies (log)	0.190	0.048	0.108	3.978	0.000

SEM—Standard error of mean | SPRC—Standardized Partial Regression Coefficient

For figures & images - - click here

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