Diversity of fruit fly species (Diptera: Tephritidae) associated with citrus crops (Rutaceae) in southern Benin in 2008–2009

Fruit flies are pests of economic importance in many fruit crops. Little was known about Tephritid diversity in citrus orchards in southern Benin prior to this study. Traps baited with parapheromones were set in citrus orchards from August 2008 to August 2009 in the Atlantique, Ouémé and Zou departments to identify fruit fly species and monitor the fluctuation of their populations. Citrus fruits were also sampled during the citrus season (from August 2008 through August 2009) at two-week intervals and assessed in the laboratory for fruit fly damage. Other cultivated and wild fruits near the citrus orchards were also collected. The fruit fly detection trapping showed that Bactrocera invadens Drew Tsuruta & White followed by Dacus bivittatus(Bigot), was the most predominant species recorded in Citrus orchards. Bactrocera cucurbitae (Coquillett) was also recorded along with six species of Ceratitis. From all fruits sampled, the emerged fruit fly species wereprimarily B. invadens (98.3%), followed by B. cucurbitae, Ceratitis fasciventris (Bezzi), Ceratitis ditissima (Munro), Ceratitis anonae Graham and Dacus punctatifrons Karsch. The infestation rate was highest on Citrusreticulata Blanco (22%), followed by C. tangelo Macfad (18.7–19.7%) and Citrus sinensis Osbeck (5.3– 8.74%). These results are significant for the decision-making process for effective monitoring and managementof B. invadens in citrus orchards in southern Benin

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

<div><p>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, <i>Oecophylla longinoda</i>, two species of fruit flies that are primary pests of mango fruits, <i>Ceratitis cosyra</i> and <i>Bactrocera dorsalis</i>, and their two exotic parasitoids, <i>Fopius arisanus</i> and <i>Diachasmimorpha longicaudata</i>. 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 <i>B</i>. <i>dorsalis</i> and <i>C</i>. <i>cosyra</i> respectively. Similarly, parasitoid reproductive success was negatively affected by ant presence, with success of parasitism reduced by around 50 percent for both <i>F</i>. <i>arisanus</i> and <i>D</i>. <i>longicaudata</i>. 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.</p></div