Diversity and availability of edible caterpillar host plants in the Luki biosphere reserve landscape in the Democratic Republic of the Congo

Abstract

Edible caterpillars are an important food and economic resource for rural African people. However, they are subject to a number of threats; in particular, their host plants are threatened. The Luki Biosphere Reserve landscape is a region of the Democratic Republic of Congo where the practice of eating caterpillars is a recent phenomenon; however, rural communities have reported their scarcity. This study assessed the diversity and availability of host plants of the edible caterpillars in the Luki Biosphere Reserve (LBR) landscape. Botanical inventories were conducted in eleven ha plots of each of the following habitats: forest, savannah under protection, fallow, and inhabited areas, covering an area of 44 ha. The coverage-based rarefaction and extrapolation method and the iNEXT online software were used to calculate the true diversity of edible caterpillar host plants. The diameter structure of the edible caterpillar host plant species was assessed by counting the number of individuals in each diameter class. The results revealed that in the Luki Biosphere Reserve landscape, edible caterpillars rely on 15 main plant host species (Spondias mombin L., Petersianthus macrocarpus (P.Beauv.) Liben, Croton sylvaticus Hochst. ex Krauss, Hymenocardia acida Tul., Lannea welwitschii (Hiern) Engl., Macaranga spinosa Müll.Arg., Celtis mildbraedii Engl., Coelocaryon botryoïdes Vermoesen, Albizia gummifera (J.F.Gmel.) C. A. Sm, Bridelia atroviridis Müll.Arg, Ficus mucuso Welw. ex Ficalho, Funtumia elastica (P.Preuss) Stapf, Lannea welwitschii (Hiern) Engl., Milicia excelsa (Welw.) C.C. Berg., and Terminalia superba Engl. & Diels). The habitats exhibited low species diversity of the edible caterpillar host plants. Moreover, several of these species are becoming scarce or are locally threatened with extinction. The trend in the diametric structure is similar to species evolving in a disturbed environment.The results of this study suggest potential habitat instability linked to human activities that could lead to biodiversity loss and, thus, a decline in edible caterpillars in the LBR landscape. A better understanding of the unfavourable conditions that influence the nutritional support for the edible caterpillars would help promote appropriate strategies that can be applied in local development plans for community lands at a landscape scale.