Beneficial Insects

Scientists studying pollination are delighted by evidence that native insects are highly valuable in helping pollinate our food and forage crops, as well as native plants. The bugs buzzing and crawling around our environment, sometimes stealthily, have been identified as the secret agents often doing the heavy lifting when it comes to pollinating crops — previously thought to be largely the domain of bees. And many are also doing double duty, helping to control insect pests.   

Step aside the humble bumble and honeybees. There are new pollinating kids on the block. Well, not exactly new, as our native insects have been around a long time, but just how valuable they are as pollinators and the work they do helping to control pests is only just being fully understood.  

The Biodiversity for Beneficial Insects research project, supported by MPI’s Sustainable Food and Fibre Futures (SFFF) Fund, confirms the significant roles our native insects play – and like it or not, native flies are heroes in the line-up. The beetles are there too, as are our native bees, of which we have 28 species.  

The project is based in the Selwyn district in Canterbury, within the catchment of Te Waihora (Lake Ellesmere). In addition to identifying insect contributions to ecosystems, it is establishing what companion native plantings work best to attract the right kind of insects, and how landowners can design these plantings to be most effective.  

Leading the research is Plant & Food Research which has partnered with the Foundation for Arable Research (FAR). They have also teamed with several other partners, including Te Ara Kakariki, a community restoration trust, and Brailsfords Ltd (an ecological restoration planting business). The group helps to provide knowledge about what plants originally grew in certain areas and to link with key ecological sites across the district. Also involved are local councils, community groups and end users, and 45 dairy, sheep, beef and arable landowners and farms in the district. The project has also involved engagement with mana whenua, initially through Te Taumutu Rūnanga, to connect with indigenous knowledge of the district, including its plants and insects. 

Senior scientist and pollinator entomologist at Plant & Food Research, Dr Brad Howlett, says rather than introducing insects from overseas or relying heavily on pesticides for crop production, farmers could now look confidently to a range of native insects to do the job of pollination, as well as help with pest control.    

“We now know that pollinator diversity is important in improving yields in many crops, compared with using honeybees on their own. Honeybees, which many farmers and growers have depended on for pollination, are not always the most efficient. Other insects can be equally or even more important for pollination, especially during conditions or times when honeybees are less active. “Improving diversity increases your chances of having the most efficient pollinators in your crop.”  

Brad Howlett adds that as beneficial native insects like native plants, establishing more native habitat on farms works to bring in a lot more diversity.    

Many farmers already have tracts of native plantings on their land, some because of retiring and protecting areas of remnant and regenerating bush, or through restoring and establishing new wetlands and riparian planting along waterways.  

Keen that these native areas are put to the most effective use, not only to improve and protect their environment, but also to attract beneficial insects, the research team has put together a roadmap for designing and establishing pollinator-friendly landscapes.   

In five easily-followed steps, advice is provided on verifying pollinators, understanding what native plant species they interact with, choosing the right plant species – amongst them mānuka, kānuka, tī kouka (cabbage tree), houhi (lacebark) and koromiko (hebe) – planting and getting them established. The fifth and final step is verifying that the planting is working to attract and support crop pollinating insects.    

Although the roadmap does not completely cover all other factors that need consideration in establishing successful habitats, such as the most effective size and location of the planting, it is being well received by a number of primary sector organisations and other groups that own land and are keen to enhance pollinator diversity including the habitats these beneficial insects require to thrive.  

Amongst them is FAR, whose environmental research leader Abie Horrocks says there are many landholders and managers interested and involved in establishing semi-natural native habitats for beneficial insects. She says there is growing appreciation that, as well as providing for targeted beneficial insects, establishing such habitats has socio-cultural values as they can help to support the wellbeing of the communities they are located in, and help maintain primary industries’ social license to operate. 

A move towards a lighter touch with integrated pest management (IPM) has been a big driver of the work. IPM aims to use insecticides in the least disruptive way and only when necessary. The days of adding in a cheap broad-spectrum insecticide as good insurance ‘because going across the paddock anyway’ and it ‘can’t do any harm’ are going. It can be highly disruptive to ecosystems, as well as expensive, and farmers are becoming more aware of how many beneficials there actually are helping them control the pests or contribute to pollination “for free”. The days are also long gone that ‘if it moves – kill it’. When it comes to insect pollinated crops, the more activity there is, the better.  

Cereal aphids are a problem pest, especially since they transmit Barley yellow dwarf virus (BYDV, a disease in cereals and grasses caused by a virus infection). But the good news is aphids are an appetising food source for native brown lacewings and hoverfly larvae, ladybirds, parasitic wasps, native carabid beetles and spiders.  

And flies are not to be underestimated. The Hoverfly is a great example where the larval stages feed on hundreds of aphids and the adult stages are important pollinators. And adults need nectar, which is where the biodiversity plantings come in. Having a diverse nectar source available is important and biodiversity plantings can help provide nectar at the right time for these beneficials and alternative pollinators. Wasps can parasitise hundreds more aphids, if they are fed on nectar as opposed to water.  

One arable farmer who put in a biodiversity planting in 2013 as part of his IPM programme to reduce the use of insecticides on his crops observes, “there are usually plenty of non-farmers’ areas, if you have a difficult corner, or an area that is not productive, why not plant it in natives?”  

Co-chair and one of the founders of Te Ara Kākāriki, is Craig Pauling. He has been involved with ecological restoration in the district for almost 20 years and is now also intrigued by beneficial insects and the work that they do.  

Craig is the current chair of the project governance group, and like Abie, he reaches into different parts of the community to help inspire native planting, including through his connection to local mana whenua, and his previous and ongoing roles with local councils and community organisations in working with farmers.  

He says the Beneficial Insects Project not only taps into the knowledge that remains of what native plant species existed previously. Canterbury is intensively farmed, with just 0.5 percent of its native vegetation left – and as a result, fewer insects, birds and other indigenous species. Craig notes the Project is also working to revitalise traditional knowledge and appreciation of the important roles native flora and fauna can play in our future.   

“Traditional knowledge of an area, including the valued mahinga kai species and practices of mana whenua, are critical to understanding the unique characteristics of our landscapes, and how people interacted and utilised these, but also how these species and practices and the knowledge associated with them remain relevant and can help in combating some of the challenges we are now facing.  

‘While the mātauranga associated with key plant, bird and fish species is quite well known, the knowledge about insects and invertebrates is less common – so this project is helping to highlight the specialness of our native insects and amazing things they do.  The fact that they can help with both pollinating crops and controlling pests, as well as enhancing biodiversity within the productive landscape is fantastic and needs to be celebrated.’ 

‘Actually, it needs to be more than celebrated – I think it is essential to how we need to farm going forward. It is a real win-win for everyone – the renewed knowledge can add to our understanding and practice of kaitiakitanga; we get more native birds, insects and birds being integrated back into our landscape helping us meet national and regional biodiversity goals; we get better outcomes for both agriculture and horticulture – so it is mutually beneficial for all parts of our community, and our environment.’ 

‘One finding from the project that really highlights this is around the Brown Lacewing – a very special native insect that is an amazing predator, especially of aphids – which I didn’t even know existed!! Through my interactions with the science team, I have learnt about the special characteristics and important role the lacewing plays – including how fierce and resolute they are. I immediately wanted to know more, so I did some further digging to see what mātauranga could be found, including if there were any recorded Te Reo names for them – but there was very little available. So, this is something we want to explore further and work with mana whenua on.  In the meantime, I was able to share that the word niwhaniwha in Te Reo refers to the fierceness that the lacewing shows – so it has become like a nickname for us.’ 

Beyond the lacewing, more is being learned about the significant roles our native bees, hover flies and spiders play and their interactions with both native plants, crops and pests.