Insects
Giant dragonfly
Fresh water insects
The rivers and wetlands of the Mackenzie Basin are home to many aquatic invertebrates including dobsonflies, mayflies, stoneflies, caddisflies, waterboatmen, red coat damselflies, and sandflies. Recent studies have found that small springs associated with the margins of large braided rivers support their own distinctive aquatic invertebrate fauna. Similarly, wetlands have other characteristic invertebrates, such as the spectacular giant mountain and yellow-spotted dragonflies.
Many kinds of freshwater insects inhabit riverbeds. Wingless larvae live beneath rocks and once they have become adults with wings, most species leave the riverbed and take to the air.
The Tasman River/Te Awa Whakamau is one of only a few sites where the uncommon aquatic caddisfly, Psilochorema folioharpax, has been found. All of these insects are also a food source for native and introduced fish, and birds.
Robust grasshopper
Terrestrial insects
Unfortunately very little is known about terrestrial invertebrates living in braided rivers, although on a warm summer day myriads of small insects and bugs can be seen swarming over low growing cushion plants in river floodplains. These insects probably play important roles in pollination of riverbed plants and are vital foundations of food webs.
One unusual insect you may see in the Mackenzie Basin is the indigenous robust grasshopper (Brachaspis robustus). This chunky, grey, rough-skinned grasshopper is found along only a few sites on riverbeds of the Mackenzie Basin, preferring to live on the newly disturbed gravels of riverbeds and outwash terraces.
Minute grasshopper
To avoid predators, the robust grasshopper relies on its cryptic coloration and remains quite still, rather than actively escaping by hopping away. It is an endangered species.
Another species endemic to riverbeds and outwash gravels of the Mackenzie Basin is the short-horned grasshopper (Sigaus minutus). It is also a threatened species, preferring to live on more stable gravels where encrusting lichens provide food and excellent opportunities for camouflage.
Other insects found in the Mackenzie Basin include boulder butterfly, cicada, tiger beetle, Tekapo ground wētā, grass moth, and chafer beetle.
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