Spider of the Week: Philoponella oweni

Uloboridae Philoponella oweni female
Philoponella oweni female (Photo credit: Jillian Cowles)

As I said in my earlier post on misconceptions concerning spider bites, not all spiders contain venom, and Philoponella oweni belongs to one such family of spiders, the Uloboridae. This family of 266 known species (World Spider Catalog) is made up of cribellate (read: spiders with an organ, the cribellum, that occurs between the spinnerets to “comb” through silk as it is produced) orb weavers that are distributed across the globe. Individuals in this family use their finely-combed silk to wrap and strangle prey, as opposed to killing prey with venom, as most spiders do.

Sociality in spiders is incredibly intriguing, given that spiders are often known for being aggressive, solitary creatures. Thus, spiders that deviate from this lonely lifestyle are of interest to researchers like myself that want to understand the evolution of social behavior. Philoponella oweni caught my interest during my early research into sociality in spiders, when I found a few older papers by Deborah Smith that detail this intriguing species’ life history. This orb-weaver is found in the Southwestern United States, and is facultatively-communal, meaning that at times individual females will build nests alone, but at other times, they will connect their nests to those of other females. What causes this difference in behavior? An absence of web attachment sites (e.g. rocks) causes females to attach their webs to the same sites as other females. Though prey-capture and brood care (behaviors found in some spiders with higher levels of sociality) in the communal webs are carried out individually, the females will sit with their egg-sacs in a communal retreat until their young emerge.

So what could this species tell us about social evolution in spiders? What I would propose is that perhaps, when habitats are crowded or scarce, tolerance of others in or near a nest is favorable for this species. What do you think?

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DRRSmith1982

DRRSmith1983

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