Adequação de uma dieta artificial para os biótipos "milho" e "arroz" de Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

GUSTAVO ROSSATO BUSATO ( 2 ); MAURO SILVEIRA GARCIA ( 3 ); ALCI ENIMAR LOECK ( 3 ); MARCELO ZART ( 4 ); ADRISE MEDEIROS NUNES ( 5 ); ODERLEI BERNARDI ( 4 ); FABIANA DA SILVA ANDERSSON ( 4 ) RESUMOSpodoptera frugiperda é considerada uma das principais pragas da cultura do milho (lagarta-docartucho) e do arroz irrigado (lagarta-da-folha), ocasionando altos índices de desfolhamento. O objetivo do estudo foi obter uma dieta artificial adequada para criar os biótipos "milho" e "arroz" de S. frugiperda (J.E. Smith), em laboratório. Os insetos foram coletados em áreas cultivadas com milho e arroz irrigado no ecossistema de várzea e a identificação foi realizada pela análise do DNA genômico. O desenvolvimento dos dois biótipos foi acompanhado sobre a dieta de Greene e a mesma dieta modificada a 25 ± 1ºC, UR de 70 ± 10% e fotofase de 14 horas. O estudo foi realizado com 150 lagartas por dieta, individualizadas em tubos de vidro e contendo dieta artificial. Por ocasião da emergência, 20 casais foram individualizados e alimentados com solução aquosa de mel a 10%. A dieta Greene possibilitou melhor desenvolvimento dos dois biótipos, proporcionando maior velocidade de desenvolvimento, maior massa de lagartas no máximo desenvolvimento, massa de pupas e fecundidade total, além de valores mais elevados da taxa líquida de reprodução, taxa intrínseca de crescimento e taxa finita de aumento. Palavras-chave:Insecta, lagarta-do-cartucho, lagarta-da-folha, biologia. ABSTRACT ADAPTATION OF AN ARTIFICIAL DIET FOR THE BIOTYPES "CORN" AND "RICE" OF SPODOPTERA FRUGIPERDA (LEPIDOPTERA: NOCTUIDAE)Spodoptera frugiperda is considered one of the main pest in corn and irrigated rice (fall armyworm) crops, causing high leaf losses. The objective of this study was to obtain an appropriate artificial diet to rear the biotypes "corn" and "rice" of S. frugiperda in laboratory. The insects were collected in areas cultivated with corn and irrigated rice in the meadow ecosystem and the identification was accomplished by the analysis of the DNA genomic. The development of the two biotypes was accompanied on Greene's diet and the same diet modified to 25 ± 1ºC, UR of 70 10% and fotofase of 14 hours. The study was accomplished with 150 larvae by diet individualized in glass tubes containing artificial diet. At emergency 20 couples were individualized and fed with aqueous solution of honey to 10%. The Greene diet made possible better development of the two biotypes, providing larger development speed, larger weight of larvae in the maximum development, weight of pupas and total fecundity, besides higher values of the net reproductive rates, intrinsic and finite rates of increase.

Biotic potential and reproductive parameters of Spodoptera dolichos (Lepidoptera: Noctuidae) in the laboratory

“…6) happens in the beginning of the adult stage, especially driven by the higher fertility and low mortality of the immature individuals shortly after emergence. These observations are similar to those reported in other studies conducted with representatives of Spodoptera where the highest fertility values are observed during the first days after emergence (KEHAT & GORDON 1975, SADEK 2001, BAVARESCO et al 2004, MURÚA & VIRLA 2004, BUSATO et al 2006, MONTEZANO et al 2013b, 2014a.…”

“…2013a), S. cosmioides (BAVARESCO et al 2004), S. frugiperda (BUSATO et al 2006); and b) fertilization of females (Fig. 5), when considering only the data from females that mated, the fecundity increases to 4,595.8, similar to the maximum reported for S. cosmioides, 4,844.4 eggs/female, that received a more suitable diet (BAVARESCO et al 2004).…”

“…The fertility of this species is much higher than that observed in S. albula and S. eridania reared under the same conditions (MONTEZANO et al 2013b(MONTEZANO et al , 2014a. It was also higher in S. frugiperda (male forewing length 10.5-15 mm) reared under similar conditions of temperature and diet (BUSATO et al 2006), and S. littoralis (male forewing length 12-16 mm (SOROUR et al 2011). In general, fecundity of S. dolichos was similar to that described for S. cosmioides.…”

“…2), lasts at least one more day than in S. albula and S. eridania (MONTEZANO et al 2013b(MONTEZANO et al , 2014b under the same conditions. Ultimately, the sexual maturity of S. dolichos occurs soon after emergence, as with other representatives of Spodoptera (e.g., ETMAN & HOOPER 1979, HABIB et al 1983, TISDALE & SAPPINGTON 2001, BUSATO et al 2006). Our results indicate that the initial fertilization period of S. dolichos must be between the second and the third day after emergence.…”

“…BAVARESCO et al 2004, BUSATO et al 2006, MONTEZANO et al 2013b, 2014a, indicate that larger Spodoptera species take longer to develop and have higher fecundity. Therefore, the increase in fecundity compensates for the longer developmental period of larger species, for instance S. dolichos (present study) and S. cosmioides (BAVARESCO et al 2004), i when compared with smaller species, for instance S. albula (MONTEZANO et al 2013a), S. eridania (MONTEZANO et al 2014b) and S. frugiperda (BUSATO et al 2006).…”