New Zealand has 42 known species of cicadas, and their familiar cicada click is sung by the male of the species to attract females to mate. Photo / File
New Zealand has 42 known species of cicadas, and their familiar cicada click is sung by the male of the species to attract females to mate. Photo / File
If you're worried New Zealand's signature cicada chorus has been markedly absent this summer, don't be - the show hasn't started yet.
Over past years, bug-lovers have aired concerns environmental factors - sodden soil, frosts and not enough sun and wind - are hurting population numbers before cicadas rise aboveground to mate.
But Landcare Research invertebrates expert Associate Professor Thomas Buckley said people were only hearing smaller clapping cicadas, one of two main species, which began singing in November.
The louder, larger, most common, and better-known chorus cicadas weren't due in our gardens until next month.
"People always ask 'where are the cicadas?' but they kind of forget that it's more of a late summer thing," Buckley said.
New Zealand has 42 known species of cicadas, and their familiar cicada click is sung by the male of the species to attract females to mate.
Once they mate the female lays eggs on twigs and trees.
When the eggs hatch several months later, the tiny flea-like nymphs head for the ground, where they make tunnels, migrate through the soil, and feed on plant roots.
After six years underground, they emerge again.
Adult cicadas only live for three to four weeks - enough time to mate and begin the life cycle again.
The enigma of New Zealand's stick insects
New Zealand stick insects could teach us about how species spread and evolve in new climates. Photo / Supplied
Meanwhile, Buckley is investigating the fascinating temperature-regulating ability of New Zealand stick insects.
Temperature is a critical factor in governing the distribution of plants and animals, and all species hold a "thermal performance" that allows them to flourish under a given temperature regime.
What wasn't so clear, however, was what happened when species used to warm and stable environments colonised a variable temperate environment - and whether they could adapt.
Solving that question could help us understand and predict the evolution and spread of species over time.
The answer could lie in the physiology of New Zealand stick insects, who will be compared with their tropical relatives in a new study just awarded a $925,000 Marsden Fund grant.
"We will collect live stick insects and then measure their 'performance' under different temperature regimes that mimic what they experience in the wild," Buckley said.
"Performance will be measured by seeing how rapidly they feed and digest under different temperatures."
In insects, such functions were tightly connected to temperature of the environment.
Next, the team would look at how the genetics of these species controlled these differences.
This would be done by a combination of genomic experiments that showed how gene were turned off and on - something which could reveal how these species evolve and adapt to new environmental conditions.
"The history of New Zealand is one of continual environmental and climatic change," Buckley explained.
