The Fijian cicada or Nanai (Raiateana knowlesi) is an insect described as having a body length (without wings) of 33mm male, 29.4 to 34.8 mm female, forewing length ranging from 43.8 to 45.5 mm male (female unknown), head width ranging from 10.3-11.4 mm male; 11.5-12.8 mm female, pronotum (collar = first segment of thorax) width of: 11.7-12.6 mm male; 12.3-14.8 mm female, and mid-thorax width = 8.5 – 11.6 mm male; 9.6-12.3 mm female.
Fiji has 19 endemic (sub) species of cicada. Of these, only Raiateana knowlesi is known to have an 8 year fixed life cycle. The Fijian cicada (R. knowlesi) is distinguished from the other cicadas in Fiji by the blood or rusty coloured tinge at the base of its wing, and the black markings on its body (Figure 1.0). The Fijian cicada like all other insects has three main body sections: the head, thorax and abdomen, and six legs. The cicada only develops its wings in its last life stage, as it emerges out of the ground and removes its hard casing. Cicadas belong to the order Hemiptera. In Fiji, Cicadas are generally known as ‘makā’. Only the Fijian cicada (R. knowlesi) is called the “nanai”.
Previously only recorded from Matokana in the Navosa Province and then in the Garrick Forest reserve in Namosi in 2009, the 2018 emergence showed that the distribution also covers the Serua Province.
Habitat, Ecology and Behaviour
There is little known on the ecology, habitat and behaviour of the Fijian cicada. Raiateana knowlesi is a periodic cicada that emerges from the ground every 8 years. In general, these insects are known to undergo three major life stages; egg, nymph and adult. The nymphal stage is the longest stage (8 years) during which they feed on root sap and nutrients while developing underground. The transformation from nymph to adult involves losing their nymphal casing and the drying of their newly developed wings. The adults only live for a few weeks during which time they search for a mate. Gravid females then punch holes into branches where they deposit their eggs before dying out. The eggs, hatch and small nymphs drop into the ground. They burrow into the ground and continue their life cycle unseen. You can watch the video of the emergence here.
The main known threats for this unique species include: – introduced mammals (pigs, mongoose, cats and rats), human disturbances (especially forest fires, infrastructure development and mining) and human consumption.
Raiateana knowlesi is not listed under the IUCN redlist. The lack of data on the Fiji nanai (and most of Fiji’s other endemic insects) has resulted in no determination being made of its conservation status. This lack of data highlights the need for a comprehensive study, or a search for the insect before it is too late and it disappears from Fiji forever.
- Remarks and cultural significance
• PERIODICAL = Adults are synchronized in emergence.
• Other cicadas may have long life cycles but some come out every year so it is hard to know when they went into the ground without growing them in an experimental plot.
• This endemic Fijian cicada is the only cicada in the Southern Hemisphere with a long life cycle.
Other cicadas with long life cycles are found in India (4 years), the US (13 and 17 years), in the Northern Hemisphere.
- In recognition of its conservation significance, the Fijian cicada is featured on the Fiji $100 bill.
• The known Itaukei names for cicadas are “makā or kakalu”. The name Nanai is only recorded from the clan of Emalu where it is revered as a symbol of wealth and prosperity. This symbol arises from the legend of the Nanai, as adapted below from Dick Watling’s Mai Veikau: Tales of Fijian Wildlife.
Legend of The Nanai (adapted from Mai Veikau by Dick Watling)
Mass emergence of the nanai is said to occur every eight years. This is the legend of the nanai.
Long ago, two warring chiefs from different clans of Navosa, (Cabeta of the Burenitu clan, and Lewatunibovitu of the Noimalu clan) met beside a stream in the hills of Viti-Levu, to make peace and decide exactly where the boundary between their lands should be.
After much arguing, they agreed that the Nadoi creek, a tributary of the Sigatoka River would be the perfect boundary between the Burenitu (Serua) and Noimalu (Navosa) communities. To strengthen the agreement, they exchanged traditional gifts. Lewatu ni Bovitu of Noimalu went first, presenting Cabeta with prawns, fresh from the river, saying, “Tavale, this is the Ura Dina and from now on these prawns will be your food. There will always be plenty in your streams and they will never run out!” To this day the Ura Dina (Freshwater shrimp – Macrobrachium lar) is the totem fish for the Burenitu Clan in the Serua Province.
Then it was Cabeta’s turn. He produced a small cicada which he presented to Lewatu ni Bovitu, saying, “Tavale, this is the Nanai. From now on, these cicada will be your food but they will only appear on your land every eight years.” To this day the Nanai (Raiateana knowlesi) is the totem fish for the Noimalu Clan in Navosa. Lewatu ni Bovitu thanked Cabeta, took the nanai home and released it under a shady tree beside his favourite bathing pool which he named, ‘ Nubu ni Nanai.’
Just as Cabeta promised, the Nanai only appear every 8 years but in HUGE numbers. After just a month, they go to the ancient shady tree at Nubu ni Nanai where they sing loudly all day. When night begins to fall, they all die, fall into the pool and disappear…
Duffels 1988; Watling 1986; NatureFiji-MareqetiViti (Fiji Nanai Campaign 2017 data)