Influence of Soil Edaphic Factors on Population Density of Slug, Filicaulis

Influence of soil edaphic factors on population density of slug, Filicaulis alte and snail, Macrochlamys indica Ankita Thakur* and Harjit Kaur Department of Zoology, College of Basic Sciences and Humanities, Punjab Agricultural University, Ludhiana -141004, India * Corresponding author: Ankita Thakur

Abstract Slugs and snails are found to be pest of ornamentals grown in plant nurseries. Survey of three plant nurseries viz; Rakesh , Bahadur and Hariram plant nursery located in Jalandhar District (different traffic loads) revealed that one species of slug, Filicaulis alte viz; brown slug with black spots and one species of snail, Macrochlamys indica were commonly found. Activity of both slug and snail was affected by interactive effects of various edaphic factors like soil moisture, temperature, type, pH, bulk density and porosity of soil, soil components like nitrogen, phosphorous and potassium. However, soil moisture and optimal temperature were the most effective factors to determine surface active snail and slug population. Thus it was found that both of them preferred sandy loamy alkaline soil along with high moisture, nitrogen, particle density, porosity but low bulk density. Density of both slug and snail was maximum in Rakesh plant nursery, moderate in Bahudur plant nursery and minimum in Hariram plant nursery.

Keywords: Filicaulis alte, Machrochlamys indica, edaphic factors, soil components

I. Introduction Snails and slugs are vital components of healthy forest ecosystems, aiding in decomposition and soil building processes, and providing food and essential nutrients to wildlife. Land mollusks require moisture for respiration and locomotion, and moist-to-wet, humid microenvironments are known to be a prerequisite for the occurrence of many gastropod species (Kappes 2006). The migratory behaviour of slugs and snails was greatly affected by the microclimatic conditions in their habitat. Slugs are active at night or on cloudy or foggy days and cause serious damage, as they build up large population in local area, so are gregarious feeders (Kharbade et al 2007). 1500 species of snails and 15 species of slugs have been reported in India. Damp and shady conditions prevailing in plant nurseries provide ideal habitat for gastropods, the prevalence of which needs to be assessed (Kaur and Kaur 2004).

So the present study was conducted to study the influence of edaphic factors on population density of slug, F. alte and snail, M. indica in plant nurseries located at different localities.

II. Materials and Methods Plant nurseries at Jalandhar i.e. Rakesh, Bahadur and Hariram nursery were surveyed and the population density of gastropods (slugs and snails) was studied throughout the year by placing bricks at 10 spots per nursery during the evening hours (1800-1900 hours). Gastropods under these bricks were collected in the morning (0600-0700 hours) of the third day. The length and breadth of the collected specimens were measured along with their weight in the laboratory. The soil moisture and temperature were also recorded to find the relationship of these edaphic factors with population density of slugs and snails. For soil analyses, the surface (0-15 cm) and sub surface (15-30) soil samples from three nurseries were collected using a 5 cm diameter auger. Each sample was

@IJAPSA-2016, All rights Reserved Page 60 International Journal of Applied and Pure Science and Agriculture (IJAPSA) Volume 02, Issue 09 [September- 2016] e-ISSN: 2394-5532, p-ISSN: 2394-823X replicated three times. These soil samples were air dried (except for measuring soil moisture) in shade, crushed to pass through a 2 mm sieve and stored in sealed plastic jars for further analysis. Soil texture, pH, Electrical Conductivity (EC), organic matter, nitrogen phosphorous, potassium, bulk density, particle density, porosity were analysed in laboratory of soil sciences.

III. Results and Discussion Slug and snail population density was highest in mid of August, 2012 being 2 ± 0.58 per m2 of slugs and 1.7 ± 0.82 per m2 of snails, when the soil temperature was 26oC (eve) at 5 cm, 25oC (eve) at 10 cm, 18.5oC (mor) at 5 cm, 18oC (mor) at 10 cm and soil moisture was 32.71 % in Rakesh plant nursery (Fig 1, Table 1). In Bahadur plant nursery, slug and snail population density was highest in the mid of August i.e. 1.9±0.79 slug per m2 and 1.4 ± 0.45 snail per m2 when the soil temperature was 26oC (Eve) at 5 cm, 25oC (Eve) at 10 cm, 18oC (Mor) at 5 cm, 17.5oC (Mor) at 10 cm and soil moisture was 32.65%. (Table 1, Fig 2). On the other hand, In Hariram plant nursery, population density of both slug and snail was also maximum in the month of August (2012), slugs were 1.5 ± 0.29 per m2 and 0.9± 0.60 per m2 of snails, when the soil temperature was 26.5oC (eve) at 5 cm, 25oC (eve) at 10 cm, 19.5oC (mor) at 5 cm, 18oC (mor) at 10 cm and soil moisture was 32.33% respectively. It means these soil conditions were optimum for both slug and snail population (Fig 3, Table 1).In earlier studies also it has been found that terrestrial gastropods are particularly vulnerable to elevated temperatures and reduced humidity (Asami 1993, Baur and Baur 1993) which can have serious negative effects on gastropods, resulting in decreased population densities, and even resulting in local extirpation of less abundant species (Bloch and Willig 2006). Overall slug and snail population was significantly more in Rakesh plant nursery followed by Bahadur plant nursery and least in Hariram plant nursery. It was observed that the conditions of Rakesh plant nursery were more favourable for both slugs and snails. High density of slug and snail population might be due to high organic matter content, phosphorous, nitrogen, porosity, less bulk density of soil and sandy loam texture of the soil (Table 2). Slugs preferred sandy clay loam, alkaline soil, high in organic matter (at 0-15 cm depth), nitrogen, phosphorus, potassium, porosity and low in bulk density at Kaddon village vegetable fields (Kaur and Mehta 2012). The number of both slugs and snail was slightly less in Bahadur plant nursery than Rakesh plant nursery. It might be due to soil composition i.e. loamy sand, soil rich in organic matter, phosphorous content, less compaction of soil etc. and less bulk density that favoured the survival of these gastropods in Bahadur plant nursery. In case of Hariram plant nursery, density of both slugs and snails was low. It might be due to different texture of soil i.e. silty loam, its less porosity, less organic matter content and high bulk density which was unfavourable for the survival of both slugs and snails. The activity of slugs was affected by interactive effect of various ecological conditions like soil temperature, soil type, soil moisture, availability of shade, shelter and presence of damp conditions (Kaur and Kaur 2006).

IV. Coclusion

So, it was concluded that in slug, F. alte and snail, M. indica density is effected by soil edaphic factors. However, soil moisture and optimal temperature were the most effective factors to determine surface active snail and slug population in all the three plant nurseries.

Fig 1: Population studies of slug, F. alte and snail, M. indica in Rakesh nursery at Goraya in relation to edaphic factors during year 2012/13 (ST- Soil Temperature, SM- Soil Moisture)

Fig 2: Population studies of slug, F. alte and snail, M. indica in Bahadur nursery at Phagwara in relation to edaphic factors during year 2012/13

Fig 3: Population studies of slug, F. alte and snail, M. indica in Hariram nursery at Phagwara in relation to edaphic factors during year 2012/13

Table 1: Correlation coefficient (r) among weather factors and population of slug, Filicaulis alte and snail, Macrochlamys indica in three plant nurseries located at different traffic load at Goraya and Phagwara of District Jalandhar

Correlation coefficient (r) with Rakesh Nursery Goraya (Least Bahadur Nursery Phagwara Hariram Nursery Phagwara traffic) (Moderate traffic) (Heavy traffic) Animal ST ST ST ST ST ST ST ST ST ST ST ST (Eve- (Eve- (Mor- (Mor- SM % (Eve- (Eve- (Mor- (Mor- SM% (Eve- (Eve- (Mor- (Mor- SM% 5cm) 10cm) 5cm) 10cm) 5cm) 10cm) 5cm) 10cm) 5cm) 10cm) 5cm) 10cm)

Slug 0.61** 0.61** 0.49* 0.51* 0.85** 0.67** 0.69** 0.58** 0.61** 0.87** 0.45* 0.41 0.47* 0.40 0.65**

Snail 0.82** 0.83** 0.66** 0.68** 0.86** 0.62** 0.61** 0.54* 0.58** 0.74** 0.60** 0.58** 0.58** 0.56* 0.57**

Critical value of r at 5% = 0.455, Critical value of r at 1% = 0.575 * Significant at 5% ** Significant at 1% ST (Eve- 5cm) = Soil temperature (Evening) at 5 cm depth in oC, ST (Eve-10cm) = Soil temperature (Evening) at 10 cm depth in oC, ST (Mor-5cm) = Soil temperature (Morning) at 5 cm depth in oC ST (Mor-10cm) = Soil temperature (Morning) at 10 cm depth in oC, SM = Soil moisture

Table 2: Analyses of different soil components in three plant nurseries located at roads of different traffic load in district Jalandhar Goraya Phagawara Rakesh Sr. Bahadur Nursery Hariram Nursery Soil characteristics Nursery(Least traffic C.D% No (Moderate traffic (Heavy traffic load load- Dallewal link load-Banga link road) -NH -1) road) 1. Soil pH 8.5±0.02 8.4±0.05 8.2±0.05 0.19 2. Soil EC (dS m-1) 0.22±0.04 0.21±0.03 0.14±0.01 0.43 3. Sand (%) 71.97±0.67 66.46±0.85 33.45±0.78 3.27 Silt (%) 16.63±0.59 29.54±0.91 48.95±0.80 3.30 Clay (%) 4±0.47 11.4±0.52 17.6±0.62 2.28 4. Organic matter (%) 0.60±0.03 0.45±0.02 0.09±0.03 0.83 5. Nitrogen (Kg/acre) 97.22±0.94 90.94±0.67 72.13±0.64 3.24 6. Phosphorus (Kg/acre) 63.6±0.72 27.0±0.47 18.6±0.61 2.59 7. Potassium (Kg/acre) 594±0.48 374±0.94 273±0.95 3.46 8. Bulk density (g/cm3) 1.4±0.02 1.55±0.02 1.6±0.04 0.02 9. Porosity (%) 62.99±0.04 58.36±0.05 53.43±0.07 0.005 10. Particle density 2.62±0.01 2.57±0.04 2.54±0.05 0.02 Values are M±S.E

Bibliography [1] Asami, T. 1993. Interspecific differences in desiccation tolerance of juvenile land snails. Funct Ecol., 7: 571-77. [2] Baur, A. and Baur, B. 1993. Daily movement patterns and dispersal in the land snail, Arianta arbustorum. Malacologia., 35: 89-98. [3] Bloch, C. P. and Willig, M. R. 2006. Context-dependence of long-term responses of terrestrial gastropod populations to large-scale disturbance. J Tropical Ecol., 22: 111-122. [4] Kappes, H. 2006. Relations between forest management and slug assemblages (Gastropoda) of deciduous regrowth forests. Forest Ecol Mgmt., 237: 450-457. [5] Kaur, H. and Kaur, A. 2004. Impact of weather factors on population fluctuation of slug, Filicaulis alte Ferussac on plant nurseries at Ludhiana, Punjab. Pest Mgmt Econ Zool., 12:43-48. [6] Kaur, H. and Kaur, R. 2006. Influence of various soil factors on the population fluctuation of slug, Filicaulis alte Ferrusac in vegetable fields at Malerkotla. Environ Ecol., 24: 398-403. [7] Kaur, H. and Mehta, R. 2012. Occurrence and density of Slugs, Filicaulis alte in relation to edaphic factors in fields of villages of Distt, Ludhiana., J Res Punjab Agric Univ. [8] Kharbade, S. B., Gondhali, B. V., Wayal, C. B. and Kate, R. N. 2007. Efficacy of new insecticidal poison baits against slugs under shade net condition. Pestol., 31:35-37.