Bugs and spiders make up greater than half NZ’s animal biodiversity—time to rejoice these spineless creatures

Credit: Shutterstock/PEnsell Photography

After nearly two decades of promoting native birds in an annual competition, this year Aotearoa will begin celebrating its spineless creatures.

New Zealand is home to more than 20,000 species of insects and spiders, accounting for well over half of all animal diversity. Many are endemic, meaning they have no other home on Earth.

Like Aotearoa’s birds, the native invertebrates have evolved largely without mammals, filling many ecological niches occupied by mammals elsewhere. The Entomological Society of New Zealand has created a Beetle of the Year competition to showcase their wonderful diversity.

The contest also promotes the power of Citizen Science through iNaturalistNZ to encourage New Zealanders to contribute simply by posting pictures of the creatures they see flying or crawling around in their own backyards or in Aotearoa, be it on the beach, on the farm or climb a mountain peak during an epic.

Scientists can use the data from these observations to learn more about the patterns, population sizes, and ecology of our unique and sometimes threatened native beetles or newcomers that could become pests.

Without invertebrates there would be no life on earth

Invertebrates are central to the functioning of ecosystems. They are pollinators and decomposers, aerating soils and controlling pests while also becoming food for other wildlife. But they remain understaffed and underestimated.

CC BY-SA“/> New Zealand is home to thousands of native insects and spiders, many of which are found nowhere else. Photo credit: Jennifer Jandt, CC BY-SA

The spider in your pantry may startle you, but you may not realize that it has been eating tiny flies and food pests. You may have hit her or taken her outside where you think she would be happier. But she was doing fine in your pantry, and she was doing you a service, too.

Two species of venomous spiders live in New Zealand: the endemic Katipō spider (Latrodectus katipo) and the Australian redback spider (Latrodectus hasselti). The odds of finding a venomous spider in a New Zealand home are slim, but it’s always good to know what it is before you hit or move.

The invertebrates in the garden – worms, centipedes, spiders – scurrying towards you when you dig a hole to plant flowers could be just as frightening. But these critters were perfectly happy in this place before they showed up. And they’ll settle back in after you put your flowers in place.

The worms dive back into the soil, fertilizing and aerating it to provide a good habitat for your plant’s roots to grow. The spiders and ants are chasing around for the little bugs that want to eat the flowers you just planted.

If you dig in your soil and find tons of creepy crawlies, congratulations! You have some fertile soil and your plants will appreciate these tenants helping them to establish themselves.

Flies and wasps landing on your food or drink are a nuisance. Always check the inside of the bottle before sipping as wasps and some fruit flies are attracted to the scent of fermenting fruit. This is the hint they use to find overripe fruits in your garden and they will help you clean them up.

Some flies feed on and/or lay their eggs in chicken or cat droppings. While that may seem gross, those flies and the larvae that hatch from the eggs will clean up that mess.

Meanwhile, large wasps prey on the pests chewing on broccoli and cabbage leaves in your garden, while tiny wasps look for aphids and other critters to lay their eggs in. Many of these tiny wasps (parasitic wasps) were introduced specifically to Aotearoa to control some of our agricultural pest species.

We have come to appreciate bees and butterflies for their pollination efforts. But other insects can also pollinate. For example, there are 37 endemic species of hoverflies in Aotearoa – plus more that have not yet been described. They are often confused with bees as they have yellow and black stripes and are usually seen on flowers. Beetles, wasps and other flies can also be important pollinators for certain flowers and crops.

Most people recognize the introduced bumblebees and honey bees, but New Zealand’s 28 native bee species (Ngaro Huruhuru) are often mistaken for small flies. Ngaro Huruhuru are tiny, often black or metallic green, and mostly solitary. Some nest in groups, each digging a hole in a clay bank or undisturbed patch of soil to raise their young.

Social bumblebees and honey bees can significantly outnumber solitary bees. Ngaro huruhuru prefer small, open, aster-like flowers, many of which we think are more of a weed. Dandelions, daisies, and ragwort are the most common flowers found by native bees when foraging. Ragwort is also attractive to flies and butterflies.

Butterflies can look like little fluttering rainbows, adding color and life to the garden. As adults, they can be important pollinators of flowering plants. However, their larvae (caterpillars) require a host plant. The New Zealand Red Admiral (Kahukura), for example, relies on the native stinging nettle (Ongaonga), which is often considered a weed and removed from gardens. This limits the reproductive opportunities of these beautiful butterflies, causing a sharp decline in population in some regions of the country.

The next time you’re in your garden, take a minute to consider the insects and invertebrates that occupy the spaces on, under, and within your plants. Post photos to iNaturalistNZ to learn more about them and be sure to check out this year’s 24 nominees for the 2023 Bug of the Year competition. Voting closes on February 13th.

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Citation: Insects and Spiders Make Up More Than Half of New Zealand’s Animal Biodiversity – Time to Celebrate These Spineless Creatures (2023 6 January) Retrieved 6 January 2023 from https://phys.org/news/2023-01 -insects-spiders-nz-animal-biodiversitytime.html

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