Densidade de fêmeas de Trichospilus diatraeae (Hymenoptera: Eulophidae) por pupa de Diatraea saccharalis (Lepidoptera: Crambidae)

Abstract

Density of parasitoid females affects their capacity to develop within the host. The number of Trichospilus diatraeae (Hymenoptera: Eulophidae) females per pupa of Diatraea saccharalis (Lepidoptera: Crambidae) was adjusted to study the effect of parasitoid production in the laboratory. Host pupae were parasitised by females of T. diatraeae at densities of 1:1, 7:1, 14:1, 21:1, 28:1 and 35:1 (parasitoid:host). The females of the parasitoid remained in contact with pupae for 24 h in glass tubes (8.5 × 2.5 cm), packed in a climatic chamber regulated at 25 ± 2ºC, 70 ± 10% relative humidity and light regime of 14 h. The percentage of parasitism and emergence of T. diatraeae on pupae of D. saccharalis was 100% in all parasitoid densities. The length of thr cycle (egg-adult) of Trichospilus diatraeae was 19.25 ± 0.22 days at a density of 1:1 and 17.00 ± 0.00 days at 35:1. The offspring number of T. diatraeae was 106.00 ± 12.38 and 514.67 ± 54.55 individuals per pupa at densities of 1:1 and 35:1, respectively. The sex ratio decreased with increasing density, ranging between 0.97 ± 0.01 and 0.89 ± 0.01 at densities of 1:1 and 35:1, respectively. The percentages of parasitism and emergence of T. diatraeae on pupae of D. saccharalis were not affected by the densities of female parasitoids. The densities of 14 to 21 females of T. diatraeae per pupa of D. saccharalis are suitable for rearing this parasitoid under laboratory conditions.

Reproduction of Trichospilus diatraeae (Hymenoptera: Eulophidae) with Different Densities and Parasitism Periods in Anticarsia gemmatalis (Lepidoptera: Noctuidae) Pupae

“…The longevity of males and females did not show differences when different densities of T. diatraeae were used per pupa of D. saccharalis (VARGAS et al 2014). Melittobia australica Girault, 1912 (Hymenoptera: Eulophidae) and M. digitata present higher adult longevity at a density of up to three parasitoids per pupa of N. bullata (SILVA-TORRES & MATTHEWS 2003).…”

Pupal parasitoids for the biological control of Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae)

“…Little information is available on this parasitoid and its hosts (FAVERO, 2009). The results summarized in the literature (FAVERO, 2009;CHICHERA et al, 2012;RODRIGUES et al, 2013;VARGAS et al, 2013;CALADO et al, 2014;) indicate a high level of parasitism in D. saccharalis pupae, demonstrating its potential as a parasitoid agent that can be used in biological control programs.…”

“…Both exhibit a high rate of parasitism; however, in D. saccharalis, pupal parasitism was 100%. The search and parasitism of T. diatraeae in the pupal host D. saccharalis was analyzed by Chichera et al (2012) and Vargas et al (2013). Chichera et al (2012) performed in vitro studies and also simulated natural conditions of parasitism, showing a greater eficacy of this parasitoid in parasitism and emergence in pupae of D. saccharalis inside sugarcane stalks.…”

“…The parasitism capacity of T. diatraeae was evaluated by Vargas et al (2013) by simulating in vitro the natural conditions of parasitism of sugarcane borer in stalks. Three conditions were tested in that study, all of which involved the stalk, pupa only, pupa and larva, and pupa together with fecal material.…”

“…Volatile compounds released by plants attacked by herbivores help parasitic insects to locate their hosts (FONTANA et al, 2011). The pupae allocated with larvae had a higher level of parasitism; therefore, the authors suggested that the parasitoid is able to differentiate between components released by natural enemies in the presence of larvae, which could be close to the pupal period, in contrast to the presence of fecal material, which reduced parasitism by T. diatraeae (VARGAS et al, 2013).…”