Telenomus remus (Hymenoptera: Platygastridae) Parasitism on Eggs of Anticarsia gemmatalis (Lepidoptera: Eribidae) Compared With Its Natural Host Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

The capacity of Telenomus remus to parasitize eggs of Anticarsia gemmatalis, compared with its natural host, Spodoptera frugiperda, was evaluated under different temperatures. The parasitoid T. remus was reared at 25 ± 1°C for a single generation on both hosts. After reaching the adult stage, they were allowed to parasitize both hosts to study parasitoid biology and parasitism capacity at temperatures between 19°C and 37 ± 1°C. Egg-to-adult developmental time was similar on both hosts. The number of A. gemmatalis eggs parasitized was lower than that of S. frugiperda eggs at all temperatures. Parental female longevity of parasitoids was greater on A. gemmatalis eggs. This indicated a smaller metabolic expense during parasitism, a common feature observed on nonpreferable hosts. In general, sex ratio was little affected by temperature or hosts. When parental T. remus were reared on A. gemmatalis before the experiment, base temperature (Tb) and the thermal constant (K) were 9.53°C and 209.57 DD on eggs of A. gemmatalis and 9.68°C and 197.79 DD on eggs of S. frugiperda, respectively. When parental T. remus were reared on S. frugiperda eggs, Tb and K were 10. 12°C and 188.46 DD and 9.69°C and 190.24 DD for the evaluated host eggs of A. gemmatalis and S. frugiperda, respectively. Therefore, T. remus develops in eggs of A. gemmatalis. This can be beneficial for its use in field crops where outbreaks of both Spodoptera spp. and A. gemmatalis occur. However, A. gemmatalis is a less favorable host for the parasitoid development.

Parasitism of Locally Recruited Egg Parasitoids of the Fall Armyworm in Africa

“…This is below the 100% FAW egg parasitism reported in other settings for T. remus [25,37]. The discrepancies may be due to laboratory conditions, as the performance of T. remus is affected by temperature and humidity [40][41][42][43]. Differences may also be explained by parasitoid strains [35] , as well as the egg mass/parasitoid ratio [44] and exposure time.…”

Quality control ofTelenomus remus(Hymenoptera: Platygastridae) reared on the factitious hostCorcyra cephalonica(Lepidoptera: Pyralidae) for successive generations

“…Differences between eggs of different host species were previously identified as an important factor for survival and development of parasitoid species, such as Trichogramma spp. (Cônsoli et al , 1999) and T. remus (Bueno et al , 2014). Egg surface, egg size, chorion structures and other egg properties differ between host species, such as color during embryonic development, and volume.…”

“…Another important factor is the duration of parasitoid development (egg–adult), which the species can extend as a compensatory action to recover from low-quality food and in order to reach a larger adult size (Sequeira & Mackauer, 1992 b ). Overall, T. remus developed more slowly on C. cephalonica eggs than on S. frugiperda eggs (Bueno et al , 2014). Some differences in parasitoid development observed between C. cephalonica and S. frugiperda as hosts might be associated with the different quality of their eggs (Smith, 1996).…”

Parasitoid Complex of Fall Armyworm, Spodoptera frugiperda, in Ghana and Benin

“…In Kenya and Tanzania, authors [19] mention egg parasitism rates by T. remus above 50%. However, it must be noted that eggs parasitized by T. remus remain at least four times longer in the field than unparasitized eggs because the duration of the egg stage is only two to three days during the warm summer months [16] whereas the development of T. remus at 25 • C lasts 12 to 13 days [52]. Furthermore, parasitized eggs are dark, and thus more visible than unparasitized ones.…”