Spiders of Mysore Area

Dr Abhijith APC, Indraprastha

Introduction:

Spiders are arthropods that belong to the order Araneae , like all arthropods lack bones and internal skeleton.

More than 45,700 spider species from 113 families have been currently described worldwide. Spiders are predators which feed on a huge variety of creatures. Insects are major part of their diet. Spiders are one of the key predators which keep arthropod population in check. It is estimated that worlds spider kill 400-800 million tons of prey per year! We can only imagine what would happen if there were no spiders to eliminate these creatures!

Spider status in Mysuru:

Bird watching and Butterfly watching is more popular as a hobby with nature enthusiasts, whereas spider watching is not so popular, resulting in data deficiency. Some of us started a spider watching group called TEAM SAALIGA in order to study the spiders of Karnataka and also to create awareness among public, mainly students. So far, we have recorded 280 species from 30 families in Karnataka. The list has major contribution from Mysuru locality amounting to 200 species from 29 families, as more field trips have been conducted in 13 acres of densely vegetated Indraprastha organic farm, Kalalawadi village. Organic farming and species abundance of spider communities are closely associated; an organic farm supports variety of spiders thus keeping a check on pest, intern enhances the agriculture crop production. Present interim report is part of an ongoing study. In Indraprastha farm, it is observed that spider population increases from April month onwards and reaches peak during September and gradually decreases after December. Rarities recorded: Icius sp, Bristowia sp, Piranthus sp, Siler sp, Curubis species from salticidae family; Thwaetesia sp-(mirror spider),cf Dipoenura sp from Therididae family; Deinopus sp (Net casting spider) from Deinopidae family; Stegodyphus tibialis from Eresidae family; Cyrterachne sp, Gea sp from Araneidae Family can be considered as rarities.

The spider watching resulted in some interesting observations:

Field observations of Asemonea cf. tenuipes in Karnataka are documented. These include a possible case of oophagy by a nesting female as well as corroboration of earlier studies that described the tendency of females to deposit their eggs in straight lines within a simple shelter on the underside of leaves. Changes in colour of the female opisthosoma that include the appearance of a pair of iridescent blue lines are discussed in article https://peckhamia.com/peckhamia/PECKHAMIA_172.1.pdf

The jumping spider Myrmarachne plataleoides is a well-known visual mimic of the weaver ant Oecophylla smaragdina in south and southeast Asia. This spider is thought to gain protection by its association with these ants, but it does not prey on them and warily avoids direct contact. The attack of O. smaragdina on M. plataleoides has been described (Mathew 1954). A photographic documentation of a cooperative attack on a female M. plataleoides by a group of these ants is reported by Pavan R & David EH. https://peckhamia.com/peckhamia/PECKHAMIA_174.1.pdf

Many different insects appear to mimic the appearance of the salticid spiders as viewed from the front. Examples of this mimicry are reviewed with respect to the hypothesis that these are examples of predator mimicry, whereby salticid spiders are less likely to attack prey that present images of other salticid spiders. https://peckhamia.com/peckhamia/PECKHAMIA_179.1.pdf

Construction of orb webs as nocturnal retreats by jumping spiders. An unidentified jumping spider (cf. Anarrhotus) constructs planar orb webs that serve as nocturnal retreats. These webs are not inhabited during the daytime and do not appear to play a role in prey capture by these spiders. Their construction, involving the attachment of silk lines radiating from a hub or platform that is occupied by the spider at night, resembles the early stages of web construction by orb-weaving spiders of the family Araneidae. https://peckhamia.com/peckhamia/PECKHAMIA_182.1.pdf

Notes on the jumping spider Brettus cingulatus in Karnataka (Araneae: satlicidae:Spartaeini) appeared in journal PECKHAMIA. A series of male and female Brettus cingulatus were observed over a 38 day period on a single plant (Ficus microcapra) in Mysore, Karnataka. New observations included regeneration of legs by a female at her final molt and a male mating with a female as she tended her eggs. Occupation of a single nest site by a succession of different females and the destruction of two different B. cingulatus nests at the same site, one involving oophagy by ants also documented. https://peckhamia.com/peckhamia/PECKHAMIA_186.1.pdf

Impact of brood parasitoids and oophagy on survival of Asemoneatenuipes (Araneae: Salticidae: Asemoneinae) broods in Karnataka has been documented. There are 5 series of observation of different Asemonea,Jumping spider in Indraprstha Farm for 3 months. Field observations of spiders are difficult and usually anecdotal in nature, yet they can provide us with a realistic appraisal of spider ecology that cannot be obtained through more systematic laboratory studies of behavior. https://peckhamia.com/peckhamia/PECKHAMIA_192.1.pdf

A talk "The Music of Evolution: Exploring the Diversity of Jumping Spiders" by Prof Wayne Maddison, University of British Columbia, and the founding director of the Beaty Biodiversity Museum was delivered at RMNH Mysore. Sri Kiran Marathe (doctoral student), Saaliga team, Arivu Educational and Cultural Trust, Mysore Nature, and RMNH Mysore organised the talk. It can be observed at https://www.youtube.com/watch?v=ZQOw2vWMccU

Here is the checklist of Mysuru Spiders (as on 31/03/2021)

Conclusion:

As mentioned earlier this is an ongoing study and its interim report is presented here. Major study has taken place only in just 13 acres of land. Within a short span of two years we are able to document spider diversity and few unknown behavioural aspects, by having more knowledgeable field observers we will be able to spread our studies to entire Mysuru area in days to come and will be updated.

Acknowledgement:

Thanks are due to SAALIGA friends -Vipin Baliga, Sumukha Jawagal & Pavan Ramachandra who are part of above works. Extended team of SAALIGA supporting by providing species photos and behavioural inputs from different parts of Karnataka are also thanked whole heartedly. I am grateful to Dr David.E.Hill for whole hearted guidance and assistance in research works. Special thanks to Wayne Maddison, Nicky Bay & John Caleb identification help of species.

References:

Mathew, A. P. 1954. Observations on the habits of two spider mimics of the red ant, Oecophylla smaragdina (Fabr.). Journal of the Bombay Natural History Society 1: 61-113.