Gibbs, G. W. (1998). Why are some weta (Orthoptera: Stenopelmatidae) vulnerable yet others are common? Journal of Insect Conservation, 2, 161-166.
· Examines why some types of weta have thrived in the presence of key predators (rats), while others only exist on predator-free island refuges. Paper addresses the question of what aspects of their bilology enable some of the “demon grasshoppers” to survive while others became extinct.
· New Zealand lacked large mammals which made it a paradise for invertebrates, birds and reptiles. A consequese is the high proportion of large-bodied, flightless forms of birds and insects in the fauna
· The real impact of mammal invasions came with the Norway rat (Rattus norvegicus), which is active on the ground and the ship rat (Rattus rattus), an agile tree-climbing rate, introduced by European vessels over the last 200 years (King, 1990).
· Lists 10 reasons why weta are so vulnerable to mammal predation: 1.Their large size 2. Flightlessness 3. They are distinctly “smelly” 4. All species are nocturnally active and relatively slow moving 5.By day they retreat into a sheltered refuge 6. They may be solitary or distinctly gregarious 7. An acoustic communication system is developed and is used also as part of their defense mechanism. 8. Long development (18-36 months) from egg-adult, they are considered K selected species unlike most insects9. Oviposition is in soil or soft rotten wood 10. Omnivores
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