Development of Pseudacteon nocens (Diptera: Phoridae) on Solenopsis invicta and Solenopsis richteri Fire Ants (Hymenoptera: Formicidae)

Abstract

We studied the developmental performance of the large morph of Pseudacteon nocens Borgmeier (Diptera: Phoridae), a prospective biological control agent of imported fire ants (Hymenoptera: Formicidae). We measured selected life history traits of this parasitoid as a function of 1) host species (Solenopsis invicta Buren versus Solenopsis richteri Forel), 2) temperature (22 versus 28 degrees C), 3) source population of the fly (Corrientes and Santiago del Estero, Argentina), and 4) varied size distributions of offered host ants. Developmental periods were influenced by host species, although the populations responded in opposing manners. Developmental times, however, were most strongly influenced by temperature with total developmental periods lengthened by 17-32% at 22 degrees C. Pupal mortality was also significantly lower at this temperature. Although numbers of progeny per female were significantly higher for the Corrientes population, we found no significant differences in progeny per female according to host species. Interestingly, we found that females were larger than males, and flies from Corrientes were larger than those from Santiago del Estero, even after statistical adjustments for host size. The modal frequency of host size elected in all treatment combinations tested was identical (0.6 mm), a size that represented the apparent threshold for producing female progeny. These laboratory and additional field observations demonstrate considerable interpopulational variation in P. nocens and lend further support to the applied approach focusing at the population, as opposed to the species level, with respect to both source and target areas for classical biological control introductions of Pseudacteon flies.

Laboratory Rearing and Niche Resources of Pseudacteon spp. Coquillett (Diptera: Phoridae) Parasitoids of Solenopsis saevissima (Smith) (Hymenoptera: Formicidae)

“…The larval development time from the adult phorid flies attack to the ant host death was two days faster for P. cultellatus (12 days) compared with P. affinis (Mann-Whitney test, z = -3.40, P < 0.001) and P. disneyi (Mann-Whitney test, z = -3.72, P < 0.001) ( Table 1). The larval development period observed for the latter two species (14 days) is similar to that observed for P. obtusus on S. richteri (14,6 days) (Folgarait et al, 2005).…”

“…However, only one individual of P. affinis, P. dentiger and P. disneyi completed the development in the laboratory resulting in adults. It is likely that the high mortality of larvae and pupae was a result of the low rearing conditions (temperature of 24°C and humidity of 40-60%) compared with other studies (Folgarait et al, 2005). The larval development time from the adult phorid flies attack to the ant host death was two days faster for P. cultellatus (12 days) compared with P. affinis (Mann-Whitney test, z = -3.40, P < 0.001) and P. disneyi (Mann-Whitney test, z = -3.72, P < 0.001) ( Table 1).…”

Geographical transition zone of Solenopsis fire ants (Hymenoptera: Formicidae) and Pseudacteon fly parasitoids (Diptera: Phoridae) in the state of São Paulo, Brazil

“…The first hypothesis is that parasitoids can be species specific to the fire ants and, therefore, follow the distribution of their host. Although the development of Pseudacteon flies on non-host fire ants species is possible under laboratory conditions, the approach and attack rates are reduced compared with local fire ant species (Folgarait et al 2002, Folgarait et al 2005b. Ecological and behavioral factors are considered as so or more important as physiological and taxonomic limitations in the determination of the host range in other groups of parasitoids (Whitfield & Wagner 1988, Morehead & Feener Jr 2000, Stireman & Singer 2003.…”

“…Due to the high species richness of fire ants and the natural occurrence of parasitoids in South America, the host specificity is an important aspect to be considered when selecting natural enemies for fire ant biological control in the US (Vazquez et al 2004, Folgarait et al 2005b. Moreover, the ecological differentiation among parasitoid species such as daily activity (Pesquero et al 1996, Folgarait et al 2007a, attack place (Pesquero et al 1993, Orr et al 1997, Folgarait et al 2007b and host size (Williams & Banks 1987, Campiolo et al 1994, Morrison et al 1997 has also been demonstrated to be important in species composition of local communities.…”

Transcription profiling of guanine nucleotide binding proteins during developmental regulation and pesticide response in Solenopsis invicta (Hymenoptera: Formicidae)

“…8,9 As in all organisms, the development of ants requires multigene regulation, which is affected by environmental conditions such as temperature, radiation, and challenges from pesticides and parasites. [10][11][12][13][14][15][16][17][18][19][20][21][22] However, the role of GNBPs in Solenopsis invicta Buren development has never been examined. In this study, the complete cDNA of the guanine nucleotide-binding protein gene β-subunit (SiGNBP) was cloned and sequenced from S. invicta workers, and its transcriptional expression related to the developmental stages and pesticide response was examined.…”