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Journal of Entomology and Zoology Studies 2015; 3(4): 404-407 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2015; 3(4): 404-407 © 2015 JEZS Received: 24-06-2015 Accepted: 27-07-2015 Suresh Kondepudi Research Scholar, Dept. of Zoology, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu, India. M Kanagappan Associate Professor, Dept. of Zoology, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu S Sam Manohar Das Associate Professor, Head of Dept. of Zoology, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu.

Correspondence Suresh Kondepudi Research Scholar, Dept. of Zoology, Scott Christian College (Autonomous), Nagercoil, Tamil Nadu, India.

Life cycle of Spinotarsus colosseus (Diplopoda:

Spirostreptida: Odonotopgidae)

Suresh Kondepudi, M Kanagappan, S Sam Manohar Das Abstract The population diversity of the millipedes is huge in the soil fauna. Millipedes are better decomposers for recycling the wastes and contribute more nutrients to the soil. Spinotarsus colosseus millipede has superior ability to degrade the waste materials and close association with soil organisms. The life cycle of an organism refers to the sequence of developmental stages, which includes all these stages starting from mating, nest preparation by female parent, egg laying, incubation and development phase. In the present study the life process of the millipede S. coloseeus and their different developmental stages including their durations were observed and their morphological features were measured. Handpicked method was used for collecting the S. colosseus millipedes from the field. Afterwards they were transmuted to the laboratory and were incorporated into the culture room. The data for stage analyses were obtained by laboratory breeding and continuous observations of field-collected specimens in captivity were also made for more than one year. This paper emphasized that S. colosseus millipedes are trouble-free to rear and can be feasible for farmers. Keywords: Spinotarsus colosseus, life cycle, morphological changes, symbiotic nature, decomposer 1. Introduction Millipedes are Arthropods that may be found all over the world except Antarctica [1]. While the whole class is currently known to comprise two subclasses, 16 orders and more than144 families, considering recent updates in millipede taxonomy [2]. Among the soil animals millipedes are the important macro fauna of the soil in woodland [3]. Mostly millipedes live in dark places so sight is not well developed [4]. Spinotarsus colosseus millipede was selected based on their availability, population diversity, species richness and abundance in areas where waste materials accumulate. These are the natural soil farmers and tropical studies have emphasized the influence of millipedes on decomposition [5]. The life process study was attempted in order to obtain information about S. colosseus millipede, its morphological changes that have been occurring during its different stadial development. In millipedes (Diplopoda), geographic variation in life-cycle characteristics have been documented for some species of European millipedes [6, 7]. More recent studies have emphasized the interactions of these animals with microorganisms directly responsible for decomposition [8]. S. colosius also exhibits very close symbiotic relationship with other organisms. The presence of millipedes has also been found to greatly increase with the release of litter nutrients into the soil, especially calcium and nitrates [9]. They comminute the litter and help in the mixing up of this with the soil minerals [10]. Their excrements affect soil structure by the formation of soil aggregates, which provide good aeration and drainage. Increase in nitrogen was reported by many researchers [11]. Earlier studies on feeding behavior suggested that millipedes prefer partially degraded litter, as well as litter that is rich in nitrogen [12]. The present study brought lot of data that gave huge encourage to the eco-friendly formers. 2. Methods and materials 2.1. Site description: The present study was carried out between the period of June 2013 to December 2014. Kanyakumari (8°14’23.10’’N 77°20’’04.02’’E) is the southernmost district in Tamil Nadu, which has a varied topography with sea on three sides and the mountains of the Western Ghats as well as southernmost tip of Peninsular India. It has rainfall both during the southwest and northeast monsoons. The southwest monsoon starts from the month of June and ends in September, while the northeast monsoon starts from the month of October and ends in the middle of the December. The conductive climate with a rich diversity of soil fauna and

 

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flora available and Western Ghats are situated on the western side of the district, favoring rich millipede population along its tracts. 2.2. Animal description: Millipedes are universally present. Their populations and life cycles differ based on their habitat and climatic conditions. Millipedes were collected from the study area by handpicked method and identified by using Millipedes Identification Keys. To study the life cycle of S. colosseus is very interesting and brings a lot of information. This millipedes are very active both day and night in the places where there is no human activities. These are the specified information regarding to S. colosseus millipede.

Different parts of the millipede body

2.3. Description for the rearing chamber: The rearing chamber was constructed near the laboratory at Scott Christian College, Nagercoil (8.1700° N, 77.4300°E) with the help of clay soil and bricks. These clay soils are characterized with high water holding capacity for long period so that millipedes feel comfortable as they were in their natural habitat. The measurements of rearing chamber is 8 feet long, 4 feet width and 2 feet height area divided into four portions and the field climatic conditions were maintained inside the chamber. A wooden roof was constructed above the rearing chamber and the nylon net was used to cover the entire chamber to prevent the predators from outside as well as millipedes from inside. They burrow through the humus for feeding and coming actively to the surface in the night to wander around. The temperature varied in the room in which they were kept in the usual way during the day from proximately 20 °C to 30 °C. The animals were provided with proper food and the temperature and moisture were maintained properly for each and every day.

Morphological measurements of spinotarsus colosseus at different stages

Life stage Period(days) Legs(pairs) Segments Length(cm) Width(cm) Weight(g) colour Eggs 190±15.5

hatching 10±3.6 Instar1st 30 ±5.7 3 5 1 0.3 0.5 White Instar2nd 60±6.2 10 12 5 0.5 1.5 White Instar3rd 180±8.2 15 17 9 0.9 3.0 Gray Instar4th 300 ±10.4 29 31 13 1.2 8.5 Red Inster5th 1year±20.2 54 56 15 1.4 14.5 Brown Pre-adult 1 ½ year±30 75 77 19 1.5 23.5 Brown

Adult 2 year±50 80 82 20 1.6 31 brown

2.4. Method followed: All the species of millipedes were brought to the laboratory and kept separately in rearing chamber. Physical measurements of each millipede such as length, width, weight, number of the segments and legs were recorded and all the animals were subjected to temperature and humidity prevalent in their field habitat and were fed with a measured quantity of feed for the first month. The compost pile was checked regularly to ensure whether it is adequately moist or not. Observations are made for each week and measurements were recorded. 3. Results and Discussions 3.1 Life cycle of spinnotarsus colosseus All the collected millipedes were deposited into the rearing chamber on June 18th 2013. The adult animals were brought into the laboratory and were placed in fresh humus known to be free of eggs or early stages. Both male and female coil

tightly together and the male millipedes released the sperm packet called spermetophores from the gonopodes (modified sex legs in 7th segments). During the mating time, the female millipedes received the sperm packet. After that male millipedes were separated from the chamber and the female millipedes prepared the nest few inches inside the soil. All these changes happened within 1-2 weeks. After the process of insemination, the female stored the sperm in the so-called spermathecae. The eggs will only be fertilized when they leave the body at oviposition [13]. At this stage the female millipede laid cluster of white or gray colored eggs. The egg-masses were found to be different for particular species. The date when the egg laid was not known for these species because the mother millipedes went inside the nest or the soil and deposited the eggs there. In S. colosseus the numbers of the eggs laid were approximately 150-200.

 

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3.2. Spinnotarsus colosseus-life stages

Egg sack 1st and 2nd instar 3rd instar 4th instar

5th instar 6 adult 7 adult 8 adult

The eggs were approximately round, 10mm in diameter, and appeared pearly, with a smooth surface. They were coated with a sticky substance that caused them to clump together [14, 15]. The duration of time for egg hatching was not less than two weeks, since first instar larvae hatched from July 31st to August 3rd. All observations were made in a dark-room. Eggs were laid in nests made of earthy faecal material, and first and second stadial juveniles left the nest soon after hatching. After laying the eggs the female millipedes shed down their exoskeleton that contain high amount of calcium. At hatching they were transparently pale white, but shortly became red in the middle and finally turned into bluish brown. Immediately after hatching out the young millipedes, which were immobile and leg less, fed the shaded materials. The young larvae were much lighter in color than the more matured ones and it took more than a year for them to reach the full size of the grown millipede [16]. In this stage all millipedes have 3 body segments along with 3 pairs of legs and they were 1 cm in length, 3mm width and 0.5g weight. The animals were very active on hatching and move about feeding on the humus. The time duration of the first instars was approximately 33-40 days for all millipede species. Second instars had 6 pairs of appendages, post-cephalic segments and were 5cm. in length, 5mm in width and 1.5 g weight. Juveniles were normally completely pallid white or with a faint pattern which was much lighter than the adults.The third instars possessed paired legs, body segments and cephalic segments and increased in size, approximately 9mm. in length,9mm width and 3.0 g weight and the data were tabulated was a table. The time duration of the second instars was approximately 31 days. Fourth and sixth instars underwent modifications and all these stages are called premature stages. The characteristics of the developmental stages are summarized in Table 1. In every stages of their life cycle, the millipedes add segments and legs as they mature. It takes about 1-2 years for the millipede to mature fully, and it will continue to live several years as an adult and the adults are brownish in color. Adult stage is the prolonged stage in millipedes life which is about half of their life cycle. The mating starts from this stage and continuous for a little while. Gonopods development in the males of millipedes resembles the other millipedes. In the third and forth larval stage no sexual dimorphism can be observed in the appendages. In the fifth larval stage in the anterior pair of legs of the 7th post-cephalic segment there appear two very small raise domes. In the sixth larval stage these have become slightly larger. In the sixth and seventh larval stages proximal and distal segments are plainly apparent in adults. The post-embryonic

development consists of seven stadia (instars), which can be identified by counting the number of body rings, and the sexes can be distinguished from stadium IV onwards [17]. In many organisms, ongoing climate changes affect the timing of life-cycle events such as activity, growth and reproduction [18]. 4. Conclusion The present study was carried out to observe the life cycle of the S. colosseus and their behavior towards the environment. The S. colosseus is a very active and important millipede plays a vital role towards recycling the wastes materials and adding the nutrients back to the soil. Studying the biology of this animal brought lot of new data that gives huge support to the people who are unaware of the millipedes and their role on the environment. Now a day’s every where the deposition of the waste increased in an alarming rate and nature also find it difficult to degrade the whole waste with in the period of time. So many methods are available for solving this problem. Using millipedes as a bio-composting agent is one of the alternative methods where the waste materials are lodge. The main objective of this study is to bring the awareness among the formers and to introduce millipedes as a soil friendly and formers friendly animals to the agricultural lands. 5. Acknowledgements I am very much obliged to Directorate Collegiate Education (Chennai) for providing the financial support for my entire Ph.D work. 6. References 1. Hoffman RL, SL Golovatch, Adis J. Environments and

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