page_title: Diogmites
section_title: Biology
hierarchical_section_title: Diogmites / Biology
caption_attribution_description: English: Hanging-thief Robber Fly - Diogmites properans (?) - Okeefenokee Swamp National Wildlife Refuge, Folkston, Georgia. This type of Robber Fly is called a Hanging Thief because of its habit of hanging from vegetation with its forelegs, while holding prey with its other two sets of legs. Previous to this, it has captured the prey in the air by stabbing it with its proboscis. Also from its proboscis, it injects digestive juices which liquefies the insides of the prey. Still using the proboscis, it sucks the juices out.
context_page_description: Diogmites is a genus of mainly neotropical flies in the family Asilidae or robber flies.
context_section_description: Adults of Diogmites species hunt as ambush predators, taking off from a resting position on the ground or on branches to intercept other flying insects, or to pounce on perching/crawling prey. After prey capture, these flies will feed in a characteristic posture that has earned this genus the common name of Hanging Thieves: they will hang from plant stems or leaves suspended by one or both front legs, with the other legs holding and manipulating the prey while feeding. Presumably the relatively long legs and reduced prosternum of the genus are part of adaptations to facilitate feeding during this suspended posture.
  Hanging thieves should not to be confused with predatory scorpionflies of the family Bittacidae which are commonly called Hangingflies and which actually capture flying prey in a suspended posture.
  Many observations of the suspended feeding posture of Diogmites were caught on camera, for example Herschel Raney's webpage for Dasypogoninae includes images of D. angustipennis, D. platypterus and D. missouriensis feeding on a variety of insects. Chris Thawley has an interesting video of a feeding adult manipulating a large prey wasp while in hanging posture. Observations of the moment of prey capture are unfortunately not recorded yet in any literature or web resources. Some species can assume an unusual flight posture, with the first and last leg pairs raised high while the middle legs are extended downwards (personal observation of low-flying D. angustipennis males and females in central New Mexico). This might represent a peculiar type of hunting-related behavior more commonly referred to as orientation flights, or perhaps might serve purposes unrelated to hunting, such as a defensive posture to reduce odds of capture by dragonflies or other robberflies, or behavior intended to facilitate latching onto plant stems and leaves for landing.
  Robert Lavigne's Predator-Prey Database for the family Asilidae has 443 records of observations for at least 20 species of Diogmites feeding on a wide range of prey, including other asilids as well as dragonflies. Particular species can be selective in prey choice however, for example D. crudelis was observed to feed on Diptera or Hymenoptera in 89 of 93 cases. Very little is known about larval biology, but D. misellus and D. neoternatus larvae were respectively observed and surmised to feed on scarabaeid grubs. Larvae appear to live and pupate in soil, adults emerge after the pupae break through the soil surface to expose the anterior body. Whitney Cranshaw has captured emergence of an adult D. angustipennis in a series of remarkable photographs available at Zipcodezoo. Norman Lavers' Illustrated Field Guide to The Robber Flies of Crowley's Ridge, Arkansas details egg-laying behavior of D. platypterus and includes a more detailed photo of a protruding pupal cuticle.
caption: Diogmites properans (?) demonstrating the suspended feeding posture of a typical Hanging Thief
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