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 Major Groups | Insecta (insects) | Hemiptera (bugs) | Mesoveliidae
 

Mesoveliidae

Major Group: Insecta
Order: Hemiptera
Family: Mesoveliidae

Descriptive Features:

  • body elongate to ovoid, typically greenish to brown
  • head large and elongate, projecting well beyond the eyes
  • ocelli present, except in apterous adults
  • antennae 4-segmented
  • rostrum 4-segmented, with maxillae strongly serrated
  • adults with an omphalium metathoracic scent gland
  • tarsi 3-segmented, segment 1 very small, claws apical
  • nymphs with reduced dorsal scent glands on terga 3 and 4
  • wing polymorphism common, Austrovelia is always apterous, winged forms have an exposed, enlarged, bipartite scutellum (undeveloped in apterous species and forms)
  • forewings are homogeneous with clavus and membrane (lacking veins) of similar texture, corium with 2 - 3 closed cells
  • Total length: 1.2 - 4.5 mm
  • Taxonomic Checklist: Genera
    Austrovelia

    Mesovelia

    Distribution:
    Mesovelia
    all states
    Austrovelia queenslandiae has only been found in Cape Tribulation, Qld.

    Sensitivity Rating: SIGNAL grade 2

    Functional Feeding Group: predators

    Ecology: Instream habitat: The semi-aquatic mesoveliid bugs occur in well vegetated stagnant water, including permanent or temporary ponds with water lilies, billabongs and pools in river beds with algal growth. A few Mesoveliidae species live on water soaked moss or seeping rock faces and there are a few records from brackish water and mangrove swamps.
    Feeding ecology: Mesovelia species are predators or scavengers on small invertebrates, feeding on microcrustaceans (Crustacea: Ostracoda, Cladocera), dead or dying mosquitoes (Diptera: Culicidae) and midges (Diptera: Chironomidae). Like the larger water striders (Gerridae), mesoveliid bugs can detect their prey by vibrations on the surface of the water.
    Habit: Mesoveliidae species are dimorphic, they may be apterous (wingless) or macropterous (winged) Commonly known as ‘water treaders’, mesoveliid bugs walk or run across the water surface, dwelling on top of the vegetation, however macropterous individuals are frequently attracted to light, indicating that they are also capable of flight.
    Life history: Biological information on the relatively new genus Austrovelia, which has only been recorded from tropical rainforest leaf litter, is limited. Austrovelia queenslandiae is thought to reproduce only in the wet season, when the rainforest would be inundated. Adults are found in September to October and in April, with nymphs found in January and April. Mating in Mesovelia species takes place on the water surface where copulation usually lasts a few minutes, after which the sexes separate. The female embeds a number of eggs in plant stems by drilling holes with a long, serrate ovipositor, with each egg in a separate hole. The lifecycle comprises five moults to reach full adult development. Adults are collected throughout most of the year, nymphs from March to April and October to November (southeastern and southern Australia), March to June, August and October to November (northeastern and northern Australia). Mesoveliid adults are sometimes found with the membranous portion of the forewings broken off and the flight muscles partially reabsorbed. This is considered to be the result of dealation i.e. breaking off the wings done by the individual insect itself. In a Mesovelia population, fully winged females are not fully hardened or coloured, and immature, whereas wingless females are dealated, mature and contain ripe eggs.
     
     
    Information Sources: Andersen & Weir 2004, Cassis & Gross 1995, Lansbury & Lake 2002, Gooderham & Tsyrlin 2002
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