Auchenorrhyncha (True bugs - Order: Hemiptera)
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Some species of cicada have 13 or 17 year cycles. The nymphs live underground, when the adults finally emerge, they all do so at the same time.
Among the Auchenorrhyncha, the cicadas are generally large (at least 15mm long) and have two pairs of membraneous wings held above the body like a tent. The adults feed by inserting their beaks into twigs or branches on trees, but the young larvae live underground. In Britain, there is probably only one species of cicada, found in the south of England.
Cicadas in the genus Magicicada in north America are known as periodic cicadas - they have very long lifecycles. There are four species of 13-year cicadas and three 17-year cicadas. The nymphs of the 17-year cicadas live underground for 17 years, feeding on roots. During this time their development is slow, and they only go through seven instars. When the adults finally emerge, they all do so at the same time, which results in millions of adult cicadas suddenly appearing together - an awe-inspiring sight!
The adults produce a species-specific sound using two membranes called tymbals, and when they emerge after 13 or 17 years the noise is deafening. The adults mate very quickly and the females lay their eggs which drop to the ground, and when the nymphs hatch they burrow underground - where they stay for another 17 years!
It has been suggested that the length of time these periodic cicadas live in the immature stage may be related to the life-cycle of their potential predators during evolution. Thirteen and seventeen are both prime numbers (whole numbers that are only divisible by themselves and by one) and it would be difficult for a predator to regulate its lifecycle to co-evolve with the 13 or 17-year cicadas.
Froghoppers are also known as spittle bugs or cuckoo-spit insects, and they belong to the family Cercopidae. In some cases their nymphs live underground, but the nymphs that are found in cuckoo-spit produce the frothy protective material to stop themselves from drying up and being eaten by predators.
The leafhoppers (Cicadellidae) are found on leaves and resemble narrow froghoppers. Like the froghoppers they can jump to avoid danger, and they also fly readily. Some leafhoppers produce honeydew. The candy-striped leafhopper Graphocephala Fennahi is an American leafhopper that has become naturalised in Britain and other European countries, and is found on rhododendron.
The remainder of the Auchenorrhyncha belong to the superfamily Fulgoroidea, the planthoppers, the largest family of which (the Delphacidae) contains over 70 British species.
Essential reading from the Amateur Entomologists' Society
A to Z of insects
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- Leaf insects
- Praying Mantids
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- Three-pronged bristletails
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- Non-insect hexapods
- Two-pronged bristletails