Observation of the Week, 3/23/16

This Stegodyphus tibialis spider seen by vipinbaliga outside of Bangalore, India, is our Observation of the Week!



Not only is this gorgeous male Stegodyphus tibialis the first one posted on iNaturalist, Vipin Baliga found and photographed it under pressure and in front of a crowd! He spotted the spider while waiting for a bus outside of Bangalore. “The bus i was waiting for would reach any minute,” he writes. “If i miss it, I would have to wait for at least 3 hours for the next one. With this in mind I quickly got my camera out and started photographing this fast little spider from every angle possible.” (He also shot some video of it.)

As Vipin followed the spider, which was a “nightmare to photograph,” he began to draw a crowd. Taking the spider in hand so it wouldn’t be stepped on, he had to “answer all the curious questions from the watching audience while holding my breath, trying to get the focus right and frame well.” After he safely released the spider, the bus soon arrived and Vipin says “the bus journey turned into a Q&A session. The interested students and local people taking a closer look at the pictures, asking all kinda questions, narrating their version of spider stories, etc.” A wonderful example of interest in nature sparking a conversation between strangers.

The spider was identified on iNaturalist by Vijay Barve, who coordinates DiversityIndia - which “started as a Yahoo group for Butterflies of India in 2001 and then expanded to other groups of taxa and Social Networks as well as now specialized portals like iNaturalist and Indian Biodiversity Portal.” His SpiderIndia project on iNaturalist has nearly 600 observations!

Siddarth Kulkarni is a spider expert who helps SpiderIndia with identifications, and he was kind enough to give me some information on this particular species. He says that S. tibialis has been recorded in India, Myanmar, Thailand and China, and that “they are mostly known to construct solitary webs on thorny plants…Phanuel (1963) records that these webs are generally kept clean than other Stegodyphus species with all prey bodies dumped in a corner of web.” And fascinatingly, “young ones of S.tibialis are reportedly known to feed upon their mother,” which is a trait found in other Velvet Spiders (Family Eresidae). In fact, mothers in the Stegodyphus genus have been known to liquefy their own insides (!) to aid in this, as spiders can only eat liquid food.

As for Vipin, his spider story session with kids on the bus is similar to his own childhood, when he was an avid bug catcher, pretending each of his captured fireflies was a “magical bulb.” On weekends he currently works for Bangalore-based NGO Wildlife Conservation Group (WCG), which is “actively executing independent conservation programs, assisting the Forest Department in their activities and conducting nature awareness programs for kids in the forest fringes.”

An avid nature photographer, Vipin says his archive of wildlife photos is “meaningless” just sitting on his hard drive. Therefore, “I use iNaturalist to give a purpose to my pictures, to share them with the scientific community and…like minded people.”

- by Tony Iwane

- You can check out more of Vipin’s awesome nature photos on Flickr.

- Here’s a detailed description of matriphagy (yes, matriphagy) in Stegodyphus lineatus spiders.