Kleptoparasitism: Freeloader Flies plague California Mantis devouring Prey on a Woody Plant

Subject:  What are these Flies eating with the California Mantis? Location:  Mount Washington, Los Angeles, California Date: 07/23/2018 Time: 07:04 PM EDT Your letter to the bugman: Dear Bugman, The California Mantis living on my Sweet Sarah clone is growing, but today was the first time I saw it with a meal, but these flies … Read more

Freeloader Flies share meal with Golden Silk Spider

Do Spiders regrow Legs? & what are these flies?
June 5, 2010
Recently had a small lynx spider on a plant in my yard (spring) missing several legs, I also noticed a golden spider missing legs in a web in winter last year. I’m curious do spiders regrow limbs lost? And also the same golden spider species seems to have flies on it or on its prey in the web, I have never seen this before and the flies seem to not care they were on a spider, and in its web..
Any idea what the flies are doing and what kind of flies they are..
Thanks, Dee
Polk County, Florida, USA

Freeloader Flies share meal with Golden Silk Spider

Hi Again Dee,
The flies with your Golden Silk Spider are Freeloader Flies in the family Milichiidae.  According to Dr. Irina Brake  who coined the English name Freeloader Flies
on her Milichiidae online website, some members of the family “are kleptoparasitic, feeding on the prey of spiders or predaceous insects.”  On the Biology of Milichiidae page, Dr. Brake indicates:  “Another very interesting feature of Milichiidae behavior is kleptoparasitism or commensalism. Species of several genera suck at the prey of spiders or predatory insects such as Reduviidae, Asilidae, Mantidae, or Odonata. Mostly they are attracted to predators feeding on stink bugs (Pentatomidae) or squash bugs (Coreidae) (Frost 1913, Robinson & Robinson 1977, Sivinski & Stowe 1980, Landau & Gaylor 1987). In almost all cases it is only the females that are kleptoparasitic. In some cases a close association between milichiid and predator has been postulated, because it was observed that the fly “rides” on the predator for some time, staying with the one predator rather than changing between different predators (Biró 1899, Robinson & Robinson 1977).”  Regarding the leg regeneration question, we have seen images of a Fishing Spider with several smaller legs, and the hypothesis is that if a spider loses its legs while very young, stunted legs may regenerate.  Alas, older spiders will not regenerate their legs.

Golden Silk Spider: double amputee

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