Spodoptera cosmioides (Lepidoptera: Noctuidae) as an alternative host for mass rearing the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)

Abstract

Abstract Different alternative hosts can reduce or even avoid pre-imaginal conditioning of parasitoids in mass production programs. Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) may be an alternative host for mass rearing the parasitoid Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae). The objective of this study was to evaluate the parasitism, emergence, egg-to-adult period, progeny size, sex ratio, and consumption of host tissue per individual of P. elaeisis produced using S. cosmioides pupae in the laboratory. Newly formed S. cosmioides pupae were weighed, individualized in glass tubes and each one was exposed to six newly emerged P. elaeisis females during 48 h. These pupae were transferred to plastic pots until the emergence of P. elaeisis adults. Palmistichus elaeisis parasitized and emerged from 100.0 % and 87.5 % of the S. cosmioides pupae, respectively. The egg-to-adult period of P. elaeisis was 24.28 ± 0.18 days, with 109 ± 2 individuals emerging per host pupae. Mass consumption of the host was 2.56 ± 0.01 mg per parasitoid emerged. This is the first report of P. elaeisis parasitizing and developing in S. cosmioides pupae. The ease of rearing S. cosmioides with an artificial diet, and the high parasitism, emergence, and progeny size of P. elaeisis support the suitability of this alternative host to mass-rearing this parasitoid.