Decline of the Commercially Attractive White Morph in Goliath Beetle Polymorphic Populations

Daniele Dendi,Giovanni Amori,Luca Luiselli,Stephanie N Ajong

doi:10.3390/d13080388

Abstract

The Goliath beetle (Goliathus goliatus) is one of the largest and most commercially valuable (for collection exports) beetle species worldwide, and occurs in West and Central Africa, with polymorphic populations being found in Benin, Eastern Nigeria, and Western Cameroun. The white morph is the most commercially valuable, and therefore is actively searched for by hunters and dealers. In a long-term, opportunistically conducted study in south-eastern Nigeria, we documented a substantial decline of the white morph compared to the normally coloured brown morph, although an overall decline in the number of observed beetles was evident for both colour morphs. Although a combination of reasons may have caused the white form decline, it is likely that overcollecting was the primary threat behind the observed pattern. Therefore, we urge the competent authorities to better protect the polymorphic populations of these giant beetles and the International Union for the Conservation of Nature (IUCN) to make a quick assessment for eventual inclusion of the species among the threatened taxa Red List.

Highlights

IntroductionMany beetle species are especially valued for collections throughout the world, with large-sized, colourful, and morphologically attractive species being valued [1]
Many beetle species are especially valued for collections throughout the world, with large-sized, colourful, and morphologically attractive species being valued [1].The Goliath beetle (Goliathus goliatus) is one of the largest [2]and most commercially valuable beetle species worldwide [3,4].Goliathus goliatus occurs in West and Central Africa, and polymorphic populations occur in Benin, Eastern Nigeria, and Western Cameroun [3,4,5], with most of the individuals being “normally” coloured and a few individuals having white elytra (Figure 1)
Our study revealed a clear decline in the observed Goliath beetles throughout the study period, with an even disproportionally heavier decline in the white morph

Summary

Introduction

Many beetle species are especially valued for collections throughout the world, with large-sized, colourful, and morphologically attractive species being valued [1]. Goliathus goliatus occurs in West and Central Africa, and polymorphic populations occur in Benin, Eastern Nigeria, and Western Cameroun [3,4,5], with most of the individuals being “normally” coloured (with brown elytra) and a few individuals having white elytra (Figure 1). In these areas, the frequency of occurrence of the white morph (named “quadrimaculatus”) is unknown. The white morph is especially hunted for by local persons (Luiselli et al, original interview data with local collectors)

Methods

Results

Conclusion