Habitat factors associated with Fopius caudatus parasitism and population level of its host, Ceratitis cosyra

Sahadatou Mama Sambo,Antonio A.C Sinzogan,Miriam Frida Karlsson,Aristide Adomou,Hippolyte Aimé Bokonon‐Ganta,Delano Ronald Togbé

doi:10.1111/eea.12858

Abstract

AbstractBiotic and abiotic factors affect herbivores and their natural enemies and understanding of their requirements may permit habitat modification enabling conservation biological control. Ceratitis cosyra Walker (Diptera: Tephritidae), an African‐native fruit fly pest is mostly parasitized by the parasitoid wasp Fopius caudatus Szépligeti (Hymenoptera: Braconidae). To assess F. caudatus habitat, the wasp parasitism levels and infestation of its fruit fly host were examined in Sarcocephalus latifolius (Smith) Bruce (Rubiaceae), a shrub of which the fruits are among the preferred hosts of C. cosyra and F. caudatus. Fruit‐collection site descriptions, including plant species presence, were analysed in relation to the target insect abundances (emergence from target fruit). Ceratitis cosyra and F. caudatus emerged from all sites; nonetheless, their population levels were associated with both abiotic and biotic factors, of which some can be manipulated. Several factors, such as cultivation level, topography, and vegetation coverage, were correlated with F. caudatus parasitism. Ceratitis cosyra infestation level was correlated with factors such as density of S. latifolius, vegetation cover, cultivation practices, temperature, altitude, rainfall pattern, and stoniness. Proximity to other fruit fly host plants correlated with both pest abundance and F. caudatus parasitism level of the fruit fly. The findings that insects’ interactions and abundance are influenced by habitat structure and that parasitism is positively related to natural habitat indicates the importance of maintaining natural habitats in closeness to cultivated areas with the aim of enhancing pest suppression by parasitoids. Further studies should attempt to identify how plant species composition in and around orchards could affect the management of tephritid fruit fly pests.

Highlights

Habitat characteristics – such as, among others, the availability of shelter, water, and food, vegetation composition, temperature regime, and environmental disturbance – affect parasitoid and herbivore presence and abundance (Partel et al, 1996)
The presence of, for example, predatory ants and invasive fruit flies potentially affects fruit fly parasitism and fruit fly infestation (Van Mele et al, 2009; Appiah et al, 2014; Migani et al, 2017). These first observations of habitat components that interact with F. caudatus parasitism may support further controlled studies of Conservation biological control (CBC) to test manipulation of abiotic and biotic factors for enhanced suitability of the F. caudatus habitat
Several descriptive factors were related to both F. caudatus parasitism and C. cosyra infestation; yet, some of those factors displayed an inverse relationship, indicating that some areas might be more appropriate for fruit flies than for the parasitoid and vice versa

Summary

Introduction

Habitat characteristics – such as, among others, the availability of shelter, water, and food, vegetation composition, temperature regime, and environmental disturbance – affect parasitoid and herbivore presence and abundance (Partel et al, 1996). Parasitism in tephritid fruit flies such as Anastrepha spp. can reach 76%, by native parasitoids (Aluja et al, 2003) and parasitism by Fopius caudatus Szepligeti in fruits infested by Ceratitis cosyra Walker can reach 30% (Vayssieres et al, 2010b, 2012; Badii et al, 2016). Fopius caudatus is among the most abundant parasitoids of known fruit-infesting tephritid flies in Africa and mainly parasitizes C. cosyra (Vayssieres et al, 2010b, 2012). Few habitat requirements for fruit fly parasitizing species – other than host flies, host fruits (Rousse et al, 2005; Quilici & Rousse, 2012), and climatic conditions (Rousse et al, 2009; Lane et al, 2018) – are known to interact with the abundance and parasitism of released braconid wasp species. Habitat manipulations might occur at small scale as creation of shelter habitats, or at large landscape scale on regional, national, or continental scale (Griffiths et al, 2008; Jonsson et al, 2008)

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