Biological studies on Bracon brevicornis (Hymenoptera: Braconidae) reared on different host larvae

Abstract

The present work was carried out to study the biological aspect of B. brevicornis when reared on different hosts (Ephestia kuehniella, Galleria mellonella, Corcera cephalonica, Sesamia cretica, Spodoptera littoralis and Pectinophora gossypiella). Our Results assured that the type of host had great impact on the durations of the immature stages and longevity of the parasitoid. The highest & lowest incubation periods were when reared the parasitoids on Pectinophora gossypiella (45.75±1.4hours) and E. kuehniella (39.87±0.95 hours) respectively, the difference was insignificant at the other hosts. Duration of larval stages was significant shorter when parasitoid reared on S. cretica (1.86±0.079 days) than the rest hosts. The longer pupation period was recorded when parasitoid reared on Pectinophora gossypiella (7.6±0.13 days), but was insignificant on the other hosts. The highest duration period of immature stage was when reared B.brevicornis on P. gossypiella (12.75±0.74 days) but insignificant difference when reared on G.mellonella [ 9.16±0.22 days ] and S. cretica [ 9.91±0.14 days ]. The mean duration of male longevity of parasitoids was longer when reared on E. kuehniella (15.73±0.73 days) and shorter when reared on C.cephalonica (11.75±0.51 days). The mean duration of female parasitoids was highest when reared parasitoids on S. cretica (19.6±0.51 days). The total number of eggs laid per female of B.brevicornis during its life span was highest on Galleria mellonella (268.88±19.65 eggs), and lowest on C.cephalonica (78.1±10.63 eggs). A percentage of eggs hatchability was significantly lowest when reared on S. littoralis (0.09±0.02642 %) than when reared on the other hosts, while percentage of emergence was insignificantly different when reared on Sesamia cretica (87.36±3.92 %) and Pectinophora gossypiella (87.02±3.85 %).

Parasitic Potential of Bracon brevicornis Wesmael (Hymenoptera: Braconidae) on Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae)

“…The findings of Ghimire and Phillips (2010) depict that B. hebetor did not lay eggs on all the host it parasitizes which reinforce the relevance of our findings. Our findings are concurrent with the findings of Bakr et al (2014) who reported that B. brevicornis preferred to oviposit on last instar larva compared to early instars. According to Kandil et al (2018) the total soluble proteins, carbohydrates, fats were present in larger quantities in bigger larvae or later instars compared to early instars, which is a key factor influencing the preference of later instars over early instars.…”

“…The longevity of adults emerged from different instars were found to be on par with each other and it ranged from 362.0 to 362.8 h. There was no significant difference between instars, with regard to developmental duration of B. brevicornis (Fig. 1) which is in line with the findings of Srinivasan and Chandrikamohan (2017) and Bakr et al (2014). In contrary, Kandil et al (2018) reported that the developmental duration was shorter on small sized hosts like Pectinophora gossypiella (Saunders) and Earias vitella (Fabricius), but longer on large sized hosts like Spodoptera littoralis (Boisduval) and Helicoverpa armigera (Hubner).…”

“…was responsible for the non -preference of the B. brevicornis. Similarly, thickness of cuticle and body contents of the host larva influence the preference of the parasitoid as reported by Bakr et al (2014). The cuticle of S. frugiperda larva is thicker compared to the cuticle of C. cephalonica larva.…”