At Lunch with a Killer: The Effect of Weaver Ants on Host-Parasitoid Interactions on Mango

Abstract

Predator-prey interactions can affect the behaviour of the species involved, with consequences for population distribution and competitive interactions. Under predation pressure, potential prey may adopt evasive strategies. These responses can be costly and could impact population growth. As some prey species may be more affected than others, predation pressure could also alter the dynamics among species within communities. In field cages and small observation cages, we studied the interactions between a generalist predator, the African weaver ant, Oecophylla longinoda, two species of fruit flies that are primary pests of mango fruits, Ceratitis cosyra and Bactrocera dorsalis, and their two exotic parasitoids, Fopius arisanus and Diachasmimorpha longicaudata. In all experiments, either a single individual (observation cage experiments) or groups of individuals (field cage experiments) of a single species were exposed to foraging in the presence or absence of weaver ants. Weaver ant presence reduced the number of eggs laid by 75 and 50 percent in B. dorsalis and C. cosyra respectively. Similarly, parasitoid reproductive success was negatively affected by ant presence, with success of parasitism reduced by around 50 percent for both F. arisanus and D. longicaudata. The negative effect of weaver ants on both flies and parasitoids was mainly due to indirect predation effects. Encounters with weaver ant workers increased the leaving tendency in flies and parasitoids, thus reduced the time spent foraging on mango fruits. Parasitoids were impacted more strongly than fruit flies. We discuss how weaver ant predation pressure may affect the population dynamics of the fruit flies, and, in turn, how the alteration of host dynamics could impact parasitoid foraging behaviour and success.

Infestation of fruit fly, <i>Bactrocera</i> (Diptera: Tephritidae) on mango (<i>Mangifera indica</i> L.) in peninsular Malaysia

“…Previous studies suggest that Oecopylla ant is an effective predator and significantly can reduced the fruit fly infestation on mango in the field[29]. It was confirmed that the number of eggs laid by fruit flies B. dorsalisand Ceractitis cosyra on mango were reduced up to 75% and 50% respectively when the weaver ants presence[20]. According to[1], fruit flies spent less time on ant-colonized mango trees compared on ant-free mango trees because they emit chemical signals (i.e pheromones)that can repel female of fruit flies from approaching the mango fruits and also the pheromones significantly affected the oviposition behavior of fruit flies.…”

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

“…Distance between host fruits and their fructification periods additionally affect fruit fly population level . The presence of, for example, predatory ants and invasive fruit flies potentially affects fruit fly parasitism and fruit fly infestation ( Van M el e et al, 2009;Appiah et al, 2014;Migani et al, 2017). Fopius caudatus emerges from some of the known C. cosyra host fruits (Vayssi eres et al, 2010b(Vayssi eres et al, , 2012 and high infestation level and high F. caudatus parasitism were observed in presence of shea tree, V. paradoxa, from which both C. cosyra and F. caudatus emerge (Vayssi eres et al, 2010b).…”

“…Another biotic factor that might affect both C. cosyra and F. caudatus is the presence of other competing fruit flies and natural enemies. The presence of, for example, predatory ants and invasive fruit flies potentially affects fruit fly parasitism and fruit fly infestation (Van M el e et al, 2009;Appiah et al, 2014;Migani et al, 2017).…”

Weaver Ants Provide Ecosystem Services to Tropical Tree Crops

“…In particular studies, the presence of ants significantly reduced pest densities of leaf-footed bugs (Coreidae; Peng et al, 1999;Dwomoh et al, 2009), mirid bugs (Miridae; Peng et al, 1999;Ayenor et al, 2007;Dwomoh et al, 2009;Forbes and Northfield, 2017a), stink bugs (Pentatomidae; Peng et al, 1999;Hosetti and Rudresh, 2012) and fruit flies (Tephritidae;Van Mele et al, 2007;Adandonon et al, 2009;Migani et al, 2017) (Figure 4A). Particular studies reported reduced pest damage from weevils (Curculionidae; (Peng and Christian, 2007;Peng et al, 2014;Abdulla et al, 2016)), fruit flies (Peng and Christian, 2006;Diame et al, 2015;Abdulla et al, 2017), and mirid bugs (Peng et al, 1995(Peng et al, , 2014Peng and Christian, 2008;Olotu et al, 2013;Abdulla et al, 2015) in the presence of ants ( Figure 4C).…”