Aspectos biológicos dos estágios imaturos de Pseudodorus clavatus (Fabricius) (Diptera: Syrphidae) alimentados com Schizaphis graminum (Rondani) (Hemiptera: Aphididae) em diferentes temperaturas

Abstract

Biological aspects of the predator Pseudodorus clavatus (Fabricius) fed on Schizaphis graminum (Rondani) were studied at different temperatures, in order to obtain information to be used in biological control of aphids. Eggs of the predator were individualized on sorghum leaf disks, kept in petri dishes and maintained at constant temperatures of 16, 19, 22, 25, 28 or 31 o C, with 12h photophase. After larval hatching, nymphs and adults of S. graminum were offered to the predator ad libitum. The duration and survival of each instar, of the larva, pupa, and larva-adult were determined. The lower threshold temperature and thermal constant were also estimated. The mean duration of the development for the three instars of P. clavatus varied inversely with temperature. Reductions were observed in the duration of the larval stage (from 14.9 to 4.9 days), the pupal stage (from 17.2 to 4.2 days) and in the period from larva to adult (from 31.7 to 8.8 days), at 16ºC and 31ºC, respectively. The lower threshold temperatures were 10.8, 11.0, and 10.8ºC for larva, pupa and larva-adult, respectively. Survival was above 78% for first-instar larvae, and above 94% for second-and third-instar larvae. The highest pupae and larva-adult survival were observed at 22 o C and the lowest survival occurred at 16ºC and 31ºC. The complete development of P. clavatus, fed on S. graminum was achieved at all tested temperatures, that varied from 16 o C to 31 o C.

Biological aspects of Eriopis connexa (Germar) (Coleoptera: Coccinellidae) fed on different insect pests of maize (Zea mays L.) and sorghum [Sorghum bicolor L. (Moench.)]

“…The longer duration of first and fourth instars of E. connexa suggest the need for nutrient storage of this predator in these instars (Scriber and Slansky, 1981;Thompson, 1999). The longer duration of the fourth instar was also found for Pseudodorus clavatus (Fabricius) (Diptera: Syrphidae) fed on S. graminum, which is interesting since there is higher predation rate in this instar (Auad, 2003).…”

“…The shorter duration of the pupa stage with fresh eggs of D. saccharalis (T3) and nymphs of R. maidis (T6) is important, because the pupa is almost static and longer duration of this stage can increase of predation and parasitism. On the other hand, increasing duration of this stage in the other treatments can be beneficial for pupa storage in mass rearing procedures, to wait for more appropriate periods for their release for pest control (Auad, 2003). Viability of E. connexa pupa was similar to that of this predator with C. atlantica , D. noxia and R. padi (Miller and Paustian, 1992;Miller, 1995).…”

Suitability of different artificial diets for development and survival of stages of the predaceous ladybird beetle Eriopis connexa

“…The reduction of the duration of the pupal stage is important for biological control programs, to obtain adults quickly to increase populations of natural enemies (Auad 2003;Nordlund and Greenberg 1994). The pupa viability of E. connexa had similar values to those of this predator with C. atlantica (Oliveira et al 2004) or D. noxia and R. padi (Miller 1995;Miller and Paustian 1992).…”

Aspectos biológicos de Pseudodoros clavatus (Fabricius) (Diptera: Syrphidae) alimentado con el áfido de las leguminosas Aphis craccivora Koch (Hemiptera: Aphididae)

“…Esta duración de la fase de larva difiere notablemente de los 9,3 y 11,8 días obtenidos por Belliure y Michaud (2001) alimentando a las larvas con T. citricida y A. spiraecola, respectivamente, a una temperatura de 23°C. Aunque la temperatura desempeña un papel fundamental en la duración de las fases preimaginales (Auad, 2003), este incremento no puede atribuirse a los dos grados de diferencia de la temperatura sino más bien a la idoneidad de las presas consumidas (Ruzicka, 1976;Du y Chen, 1993;Belliure y Michaud, 2001). Atendiendo a estos resultados, A. craccivora y S. graminum podrían considerarse presas de mejor calidad produciendo un desarrollo larvario más rápido que T. citricida y A. spiraecola.…”