Nutritional composition of three Aotearoa New Zealand caterpillar species: Impact of diet and life stage on amino acid and minerals

Abstract

Entomophagy has been practised for centuries and is rooted in many cultures, including among Māori in Aotearoa New Zealand. However, limited nutritional data exists on native edible insect species. This study investigates the amino acid and mineral composition of three endemic caterpillar species: Cleora scriptaria, Epalxiphora axenana, and Ctenopseustis obliquana. Caterpillars were reared on native kawakawa (Macropiper excelsum). Ct. obliquana was also reared on mānuka (Leptospermum scoparium) and a laboratory diet to examine the effects of insect species, diet, and lifecycle stage. Amino acid analysis using high-performance-liquid-chromatography (HPLC) showed that C. scriptaria and E. axenana had high essential amino acid content, exceeding FAO/WHO recommendations for quality protein. Amino acid composition did not differ significantly between the life stages late larvae and early pupae within the same diet, but differences were observed across diets. These results suggest that in this study a change in diet, rather than within two life stages, is a key factor influencing amino acid profiles. Mineral analysis using inductively coupled plasma mass-spectrometry (ICP-MS) showed that Ct. obliquana reared on native plants had elevated levels of K, P, and Zn, compared to the laboratory diet, while E. axenana was a good source of Fe. However, Na levels were higher in plant-fed caterpillars. Trace heavy metals were detected within safe limits within Ct. obliquana. These findings demonstrate the nutritional potential of native caterpillars as sustainable food sources but highlight the importance of diet formulation to optimise nutritional value. This study contributes to the revitalisation of traditional Māori food practices and the development of edible insect farming in Aotearoa New Zealand, with potential for domestic consumption and export markets