Genetic Diversity and Phylogeographic Structure of the Edible Caterpillars of Gynanisa maja and Implications for the Sustainability of the Species in Namibia

Abstract

Caterpillars of Gynanisa maja (Lepidoptera: Saturniidae) are extensively harvested from the wild for human consumption across their geographic range in southern Africa. Although concerns have been raised on the sustainability of this practice in the current scenario of habitat loss and climate change, genetic data for assessments of the phylogeographic structure, genetic diversity, and demographic history of the species is severely lacking. This study presents the first insights into these aspects of Gy. maja populations in Namibia using mitochondrial sequence data. Adult specimens and caterpillars (n = 72) were collected at six sampling areas in the northwestern Namibia for Sanger sequencing of polymorphic mitochondrial regions (1964 bp) followed by haplotype-based analyses. The phylogeographic structure of Gy. maja was assessed using a phylogenetic tree and neighbour-joining networks, along with estimates of genetic diversity and demographic history. We found a total of 47 haplotypes, with only a few shared haplotypes among sampling areas. Standard genetic diversity measures showed high levels of haplotype and nucleotide diversity at all sampling sites. Neutrality tests, mismatch distributions and raggedness index indicate a stationary population. Overall, our results suggest that Gy. maja in northwestern Namibia is genetically diverse and panmictic, and that the genetic diversity and demographic status of the species are presently not of immediate concern. However, it is worth noting that dry mopane woodlands, the main habitat of Gy. maja in Namibia, are under increasing anthropogenic pressure that will inevitably impact the health and abundance of these and other edible Lepidoptera, especially those harvested at commercial scale.

Keywords

African Saturniidae / genetic diversity / mitochondrial / phylogenetics / phylogeography

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2025 The Author(s). Integrative Conservation published by John Wiley & Sons Australia, Ltd on behalf of Xishuangbanna Tropical Botanical Garden (XTBG).