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Pyronota festiva
[[File:Pyronota festiva male ']]|frameless]]
Scientific classification
Kingdom:	Animalia
Division:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Family:	Scarabaeidae
Genus:	Pyronota
Species:	P. festiva
Binomial name
Agathis australis Fabricius, 1775

Pyronota festiva, commonly known as Manuka Beetle, is a member of the Scarabaeidae family of Beetles (Coleoptera) in the genus Pyronota. It is endemic to New Zealand, and is commonly found amounst the roots of Leptospermum scoparium trees, also known as Manuka trees, hense the beetles name.

New Zealand range

The Manuka Beetle is very common, as it is found in large numbers right throughout New Zealand. It lives in grass and vegetation habitats, which is of course the majority of the landscape of New Zealand. Its commonality is so much so, that it has become a ‘pasture pest’ to agricultural grass lands.

Habitat preferences

It mostly lives in tussock and grass lands, (because it is considered a ‘pasture pest’ in many agricultural areas of the country). However, as its common name suggests, it preferably lives in and around the soil of Manuka Trees (Leptospermum). Adults beetles have been seen ‘swarming’ over the small white flowers that cover the Manuka when it is flowering during the summer.

Life cycle/Phenology

Otago has been a major region for experimentation on the Pyronota species, in Macraes Flat, Otago, Stewart (1987) found that a species of Pyronota bettle followed roughly a two year life cycle where they would span across two winters as larvae and eventually mature into adult bettles over the following summer - November through to January. As evident through general observation and their preference in habitat, it is clear that warmer temperatures is something that draws the bettle to a specific area and as a result of this, it significantly increases populations; Stewart (1987) observed that adults became more active when the sun was shining as opposed to over cast days or during the night - which is interesting considering the amount of sunless days that Otago would have compared to Taranaki. However, the two year life cycle continued, eggs were found in January where they “…spent their first winter as 1st or 2nd instar larvae and their second winter as 3rd instars.” They are given a better chance of enduring their complete life cycle over two years where the conditions meet most of their need, when this isn't the case however they can develop over a shorter time period - sometimes within one year. The Manuka beetle life cycle is slightly different from those of its relatives, which include other members of the Scarabaeidae family; chafers, dung-beetles and grass grub beetles. Its eggs are laid in the soil, and after hatching into larvae, they have a reasonably lengthy development underground. The adult beetles die a very short time after mating, and their bodies often form drifts or mounds in and around mud or tree roots.

Diet and foraging

The larvae (that hatch from the eggs that are laid in the soil), feed on the roots of the Manuka tree. This is providing the eggs were laid in the soil around a Manuka tree. Larvae not in this situation have also been known to feed on Matagouri roots, and the roots of Sweet Briar Roses. In 70% of cases, larvae were found feeding in the first 4 cm of soil, directly below the ‘turf mat'. Adult Beetles feed on the vegetation of the Manuka tree. They also feed on grass roots in agricultural areas, which is the reason why they are such a pest to agriculture, as they harm the grass that the dairy cows eat. Manuka Chafers have been studied and examined a lot in the Taranaki region, however there are low numbers of adult bettles here because of their preference of food. They are not succeeding as well as possible in the Taranaki region because of their low counts of Leptospermum species existing both in present and past times. When manuka plant species are not in abundance, Manuka Chafers are being forced to feed on “…matagouri (Discaria toumatou), sweet briar (Rosa rubiginosa), and Leptospermum spp.”

Predators, Parasites, and Diseases

The green colouring of the adults, and the fact they are diurnal (active during the day), means they are safe from predators because they blend in with the vegetation on which they live on. . They must do a good job at staying hidden, because there are large numbers of them throughout the country, and there are no major predators listed for them.

However, they are a pest, so there are a number of journal articles devoted to researching how to control them by targeting them with bacteria and fungi parasites; so called ‘bio-control’ methods.

‘Rickettsiella bacteria’ is being researched as a potential ‘bio-control agent’ to manage the large numbers of the beetles affecting agricultural areas all over New Zealand. This bacterium is said to produce an ‘intracellular infection’ in the beetles, and many other members of their genus.

As well as this bacterium, a fungus called Beauveria brongniartii is being tested to help Cape Foulwind dairy farmers attack the pest. It is achieving relatively high rates of mortality in the larvae stage of the beetles. The fungal infection affects only an isolated selection of ‘scarab’ beetles, which means that it might, but is unlikely to spread onto other harmless beetles (depending on what they are).

Cultural uses

There are several records of the Manuka beetle being used by the indigenous Maori tribes all over New Zealand. The piles of dead adult beetle bodies that form in and around shallow water, mud and vegetation, were often collected and eaten by Maoris as a delicacy. Another report states that when the Maori tribes settled in New Zealand, Manuka beetles were among the insects that they occasionally ate. More fleshy insects like the larvae of the cerambycid beetle, or ‘huhu grub’ (as well as the adult beetle) were more widely eaten. Manuka beetles (and Puriri moths) were also used for medicinal purposes.

Interesting Facts

Apart from the severe damage to the farmland, Pyronota festiva has been associated to major damage in the fruit trees of peaches and nectarines. They have vast effects - with the aid of damage done by other insects - on the leaf and the fruit itself. I found this aspect of the behaviour of Manuka Bettle to be interesting because throughout all of my research the species was always only ever associated with native grass and farmlands so was interesting to see their scope of damage is quite large.