Major Group: Insecta Order: Hemiptera Family: Naucoridae Genus: Naucoris This family is represented in Australia by a single genus, Naucoris Geoffroy.
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Descriptive Features: body dorsoventrally flattened, ovoid-elliptical to broadly oval, typically blackish brown to yellowish brown and sometimes mottled
head transverse
eyes large and contiguous with the anterior margin of pronotum
ocelli are absent
antennae 4-segmented, not visible from above
rostrum short and stout, appearing 3-segmented
pronotum large, subtrapezoidal
scutellum large and triangular
forelegs enlarged, flattened and raptorial, fore femora broadly triangular
midleg cursorial
hindlegs usually modified for swimming
fore tarsi 1-segmented
mid and hind tarsi 2-segmented, with elongate claws
Total length: 6.2 - 9.6 mm
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Naucoris congrex |
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Naucoris sp. juvenile |
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Taxonomic Checklist: Species Naucoris australicus Stal Naucoris congrex Stal Naucoris magela Lansbury Naucoris rhizomatus Polhemus Naucoris subaureus Lansbury Naucoris subopacus Montandon
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Distribution: Australia wide
Sensitivity Rating: SIGNAL grade 2
Functional Feeding Group: predators, scavengers
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Ryans Billabong, Albury NSW |
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Ecology: Instream habitat: Naucoris typically occur in well vegetated stagnant waters or in sluggish backwaters of streams, amongst the vegetation and debris. Feeding ecology: Naucoris are strong predators that hide in the vegetation until prey comes along rather than chase the prey which they catch and hold with raptorial legs. They feed on molluscs (Bivalvia), small crustaceans; including water fleas (Cladocera), amphipods (Amphipoda), isopods (Isopoda), and various aquatic insects; including corixids (Hemiptera), dragonfly (Odonata), midge (Diptera: Chironomidae) and mosquito larvae (Diptera: Culicidae). Habit: Although they are good swimmers naucorid bugs generally crawl amongst the vegetation and debris, giving them the common name of ‘creeping bugs’. Naucoris species rely on atmospheric oxygen, having spiracles opening into a subalar air store, they return to the surface periodically to renew their air supply. Adults have wings and can quickly disperse from one water body to another. Life history: The biology of Australian Naucoris species is not well known. In Northern Hemisphere species, males can produce stridulatory sounds to attract females. The eggs are embedded in plant tissue under water or attached superficially to the substrate. Egg development takes about one month. There are five moults from nymph to adult, taking a further two months.
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Information Sources: Andersen & Weir 2004, Cassis & Gross 1995, Lansbury & Lake 2002, Gooderham & Tsyrlin 2002, Hawking & Smith 1997 Key to Species: Andersen & Weir 2004
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