# A new distribution and host record for the rare moth, Callioratis millari (Lepidoptera: Geometridae), and some ecological observations

## TL;DR

A rare and endangered South African moth, Callioratis millari, was found in a new location feeding on a previously unknown cycad species, offering new insights into its ecology and conservation needs.

## Contribution

The discovery of a new population and host plant for the Critically Endangered moth Callioratis millari expands its known distribution and ecological understanding.

## Key findings

- A new population of Callioratis millari was found in Kabouga, feeding on Encephalartos caffer, a new host record.
- Larval incidence and herbivory patterns were observed, with peak larval activity during the driest and coldest months.
- The species' habitat preferences include low altitudes, moderate to high rainfall, and grassy areas with sparse woody cover.

## Abstract

Callioratis millari Hampson (Lepidoptera: Geometridae) is a Critically Endangered moth endemic to South Africa. Despite extensive searches, it was previously known only from the Entumeni Nature Reserve in KwaZulu-Natal, where its larvae exclusively feed on the cycad Stangeria eriopus (Kunze) Baill (Cycadales: Stangeriaceae). In July 2022, a new population of C. millari was discovered in the Kabouga section of Addo Elephant National Park in the Eastern Cape. Larvae of C. millari were feeding on the cycad Encephalartos caffer (Thunb.) Lehm (Cycadales: Zamiaceae), which also constitutes a new host record. In June 2023, we determined larval incidence and herbivory at this new locality, offering insights into the ecological requirements of C. millari. Known C. millari localities, although ecologically different, share low altitudes (700–950 m a.s.l.), moderate to high rainfall, and grassy habitats with sparse woody cover. A total of 59 larvae were counted in Kabouga, mostly in the fifth and sixth (final) instars. Herbivory incidence was lower on smaller plants and those covered by other vegetation. The flight period of adult C. millari likely occurs between mid-March and April in Kabouga, but further investigation is needed to clarify this. The peak period of larval occurrence in Kabouga occurs during the driest and coldest months of the year (May–July). Considering limited habitat availability, host plant poaching, and the risk of untimely fires, the species should be considered highly threatened. This study adds to our understanding of the biology of C. millari and provides information on its ecological requirements and may contribute to making informed management decisions.