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Thursday, Aug. 25, 2005

ANIMAL TRACKER

River grasshopper


* Japanese name: Kawarabatta
* Scientific name: Eusphingonotus japonicus
* Description: This is a grasshopper with a mottled, stone-gray or brown body that is very difficult to spot. Males are between 25-30 mm long, females between 40-43 mm. The large hind legs (femurs) have a herring-bone pattern, and the antennae are short. Like all grasshoppers, its ears are located on the first segment of the abdomen. As well as being bigger, females have two pairs of triangular-shaped valves at the end of the abdomen that are used to dig holes in sand when they lay eggs.
* Where to find them: In August and September, in dry riverbeds from Honshu to Kyushu. The river grasshopper is threatened in some areas because of the destruction and fragmentation of riverbanks. The concrete protection work common along many rivers in Japan may damage grasshopper populations. Eggs remain in the earth over winter and hatch and grow in the spring.
* Food: Plants. Grasshoppers have mouthparts adapted for biting and chewing, and the river grasshopper eats a variety of plants. Frass (droppings) from the grasshopper returns nutrients to the soil. Birds will eat the river grasshopper -- if they can spot them.
* Special features: If startled or attacked, the grasshopper will launch itself into the air with its legs. But it can also fly; the forewings are narrow and hard and act as protection for the large membranous hindwings, which are also strikingly pigmented with the herring-bone pattern. Males don't have a penis and instead transfer sperm to the female in a package. But some female grasshoppers lay unfertilized eggs, which nevertheless develop and hatch. Baby grasshoppers that develop this way are natural clones of the female. The females can therefore avoid the unwanted attention of males altogether, or if males are in short supply they can still produce offspring. Grasshoppers grow by molting, before which they do not eat and become less active. When they want to molt, the insects swallow air and literally blow themselves up, splitting the old cuticle.



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