Patterns of resource distribution among conspecific larvae in two fruit fly species: Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

Abstract

Anastrepha fraterculus (Diptera: Tephritidae) and Ceratitis capitata (Diptera: Tephritidae) are fruit fly pests whose larvae are frequently found sharing the same fruit with conspecifics. Because larvae are incapable of leaving the fruit in search of non‐infested fruit, they are forced to share nutritional resources and eventually compete with other larvae for these. In the present study, we investigated the effect of intraspecific competition on the development of A. fraterculus and C. capitata larvae, and compared the strategies adopted by these species. To this end, newly‐hatched larvae were transferred into a container with a fixed amount of larval diet at increasing larval densities and several developmental parameters were measured. The two species showed similarities and differences in the way in which they responded to an increasing density. In A. fraterculus, pupal weight and the duration of the larval stage decreased as the competition levels increased. Larvae of C. capitata showed a consistent reduction in pupal weight and larval survival as the larval density increased. In A. fraterculus, the reduction in pupal weight was heterogeneous, with most pupae showing a marked decrease in weight and only few pupae showing slight negative effects or no effect at all, whereas, in C. capitata, the reduction was similar for all pupae. The differences in the way in which these species responded to competition suggest that there are different patterns of resource distribution among conspecific larvae. The implications of these findings for oviposition behaviour and the life history of the two species are discussed.

Coexistence between two fruit fly species is supported by the different strength of intra‐ and interspecific competition

“…An increase in density negatively affected the pupal weight, which, in most insects, is correlated with the size of the adults and their overall reproductive success (Quiring & McNeil, 1984;Averill & Prokopy, 1987;Liedo et al, 1992;Honěk, 1993;Allen & Hunt, 2001;Dukas et al, 2001;Nufio & Papaj, 2004;Navarro-Campos et al, . For C. capitata, only a small decrease in pupal weight and pupal survival was observed, which may be due to a density-dependent effect and is not necessarily affected by the identity of the competitor species (Liendo et al, 2016). 100% indicates only one species in the patch; 75% indicates 75% of one species and 25% of the other species; 50% indicates 50% of one species and 50% of the other species; 25% indicates 25% of one species and 75% of the other species.…”

“…Each patch consisted of a cylindrical plastic cup (diameter 2.8 cm, height 1 cm) that contained 3.65 g of artificial diet. This diet is regularly used in the artificial rearing of A. fraterculus and it was chosen for the current experiments because previous studies showed that C. capitata is able to successfully develop in this diet as well as A. fraterculus (Liendo et al, 2016). Sodium benzoate and methylparaben were added as preservatives.…”

“…To this end, larvae of the two species were simultaneously transferred to the same patch at the carrying capacity described for this system (patches containing 3.65 g of artificial diet; Liendo et al, 2016). For the artificial patch used in this work, Liendo et al (2016) determined that the carrying capacity was 50 larvae per patch for A. fraterculus, and 40 larvae per patch for C. capitata. For the artificial patch used in this work, Liendo et al (2016) determined that the carrying capacity was 50 larvae per patch for A. fraterculus, and 40 larvae per patch for C. capitata.…”

“…In Argentina, A. fraterculus and C. capitata widely overlap their distribution and host ranges (Ovruski et al, 2003;Segura et al, 2006;Oroño et al, 2008;Devescovi et al, 2015). Liendo et al (2016) found differences in the way in which these species responded to intraspecific competition and evidenced a different pattern of resource distribution among conspecific larvae. While C. capitata larvae facing a shortage of nutritional resources develop a strategy of resource distribution similar to that described as scramble competition (also called exploitation competition), A. fraterculus larvae showed a response similar to that described as contest competition (also called interference competition) (Liendo et al, 2016).…”

Relaciones ecológicas entre frutos hospederos, moscas frugívoras y parasitoides en un fragmento de bosque seco tropical

“…Birke et al (2015) mencionan como aspecto fundamental para prevenir la introducción de plagas cuarentenarias, conocer el uso de hospederos por parte de estas moscas; adicionalmente, el uso de hospederos por tefrítidos y su competencia inter e intra específica es un tema que se ha estudiado a nivel de ensayos en campo y laboratorio (Duyck et al, 2004 Segura et al, 2006;Devescovi et al, 2015;Lopes et al, 2015;Liendo et al, 2016). Cuando los tefrítidos invaden nuevas áreas, se puede presentar competencia jerárquica o coexistencia estable con especies preestablecidas.…”