Spodoptera cosmioides (Lepidoptera: Noctuidae) in Brazil: spatial distribution and relationship in the S. latifascia species group

ABSTRACT Spodoptera cosmioides (Walker, 1858) is an economically relevant polyphagous moth, widely distributed in the Neotropics and part of the Spodoptera latifascia (Walker, 1856) species group. In this study, we used extensive sampling from different regions to describe the spatial distribution of S. cosmioides in Brazil and evaluate its variability both from morphological and molecular perspectives. Variable coloration and several morphological similarities were found among S. cosmioides and congeners of the S. latifascia complex, diverging from each 0.5 to 3.5% of mitochondrial DNA. The genetic divergence at the species level of S. cosmioides was 0.5% throughout Brazil, and a geographic structure was absent, including shared haplotypes with S. descoinsi Lalanne-Cassou & Silvain, 1994. Spodoptera cosmioides was found in all six biomes of Brazil, with the highest abundance recorded in the Cerrado, followed by the Amazon, Atlantic Rainforest, Caatinga, Pantanal, and Pampa.

Helicoverpa armigera and Helicoverpa zea hybridization: constraints, heterosis, and implications for pest management.

BACKGROUND: The invasion of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) into the New World has made it possible for this pest to hybridize with a native American species, H. zea (Boddie), under natural conditions. We investigated the viability and development of hybrids of these two Helicoverpa species. We reared the parental species and evaluated crosses between H. armigera males and H. zea females and vice versa, two intercrosses between hybrids, and eight backcrosses between hybrids and parental species. We estimated the length of immature stages, fecundity, survival, sex ratio, and heterosis. RESULTS: Although hybridization occcurred, with heterosis during the development of immatures, reproductive incompatibilities also were observed between the parental species and between hybrids from subsequent crosses. The interspecific crosses between hybrids and backcrosses confirmed the possibility of introgression events and their perpetuation in field populations. The results indicate that hybridization events are favored at high population levels, while at low population levels the 'species identities' will be maintained. CONCLUSIONS: The possibility of interspecific gene flow and its perpetuation through successive crosses and backcrosses suggests several recommenations for management. Populations of both species should be maintained at an equilibrium level to reduce the chance of interspecific crosses, which are presumably more likely to occur during pest outbreaks. The existence of hybridization and resistance to different active pesticide ingredients should be monitored. All practices related to managing the resistance of these pests to chemical and biological insecticides should be systematized to reduce the chance of selecting for resistant individuals.

Role of nutritional composition in the development and survival of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on artificial diet and natural hosts.

Helicoverpa armigera is a pest of several crops causing significant economic impact. We evaluated the insect development on different vegetative and reproductive structures of cotton, maize, and soybean compared to artificial diet. One hundred individuals were evaluated per structure (cotton leaves and bolls; maize leaves, grains, and silk; soybean leaves and pods) and artificial diet. Centesimal analyses were performed on quantifiable nutrient contents in diets. The viability of immatures (eggs, larvae, and pupae) ranged from 30% on maize leaf to 74% on cotton bolls, while on the artificial diet, it was 70%. Maize, cotton, and soybean leaves provided viability of 30, 37, and 42%, respectively, revealing these leaves tissues are less favorable to the development of H. armigera immatures compared to 'reproductive tissues'. Centesimal composition of diets compared 14 common components in all diets, which correlated significantly with larval and pupal stages and/or pupal weight. Of the 12 dietary components that significantly affected larval development time, half were negatively correlated, indicating a decrease in developmental time from their increments. In general, when insects were confined separately to substrates, the artificial diet was the most suitable for H. armigera development compared to the evaluated natural diets. However, in natural conditions, the variability of available hosts must be considered. In addition, it is acceptable for moths to select more suitable hosts for oviposition, while their larvae move to other more suitable tissues of the same plant or even migrate to other plants.

Spatio-temporal variation of Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) populations in Brazil according to meteorological factors / Variações espaço-temporais das popupações de Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) no Brasil de acordo com fatores meteorológicos

Abstract: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) has been recognized as a major owlet caterpillar associated to the herbivory of gramineaceous plants across the American continent. During outbreaks, the caterpillars are capable of completely consuming preferred hosts (grasses) and, when these hosts are destroyed, they can move to adjacent non-grass plants and cause similar damage. Meteorological variable such as temperature and humidity are described as factors that affect the development and abundance of M. latipes. This paper aimed to describe and compare the spatial and temporal distribution of M. latipes in different locations in Brazil and to evaluate the influence of meteorological variables on the temporal range. A total of 12 locations were evaluated, in each collection point light traps were installed near cultivated areas. In order to understand the influence of meteorological variables on the abundance of M. latipes, the data were analyzed using a Generalized Linear Model according to Poisson regression. A linear regression was also used to verify the relation between the abundance and the latitude. A total of 1,985 moths were collected. The highest collections were in Amazon and Cerrado biomes. Results show that abundance was inversely related to increasing latitude and Poisson regression analysis indicated that the main meteorological variables were significantly related to abundance at each site. This study shows that due to the high preference for gramineas and the high temperature requirements (30°C), M. latipes is an important species in hot regions and regions with hight humidity. Furthurmore, even in higher latitudes, in subtropical areas, during summer months, populations can Rapidly growth being able to cause economic damages.

Resumo: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) tem sido reconhecida como uma das principais espécies consumidoras de gramíneas em todo o continente americano. Durante os surtos, as lagartas são capazes de consumir completamente os hospedeiros preferenciais (gramíneas) e, quando os hospedeiros preferenciais são destruídos, podem mover-se para plantas adjacentes não gramíneas e causar danos semelhantes. Variáveis meteorológicas, como temperatura e umidade, são conhecidas por afetar o desenvolvimento e a abundância de suas populações. Este trabalho teve como objetivo descrever e comparar a distribuição espaço-temporal de M. latipes em diferentes localidades do Brasil e avaliar a influência de variáveis meteorológicas sobre suas variações temporais. Foram avaliados 12 locais, em cada ponto de coleta foram instaladas armadilhas luminosas próximas às áreas de cultivo. Para entender a influência das variáveis meteorológicas na abundância de M. latipes, os dados foram analisados pelo Modelo Linear Generalizado, empregando a regressão de Poisson. Uma regressão linear também foi utilizada para verificar a relação entre a abundância e a latitude. Um total de 1.985 mariposas foram coletadas. Os maiores números de indivíduos foram coletados nos biomas Amazônia e Cerrado. Os resultados mostram que a abundância de mariposas está inversamente relacionada ao aumento da latitude. A análise de regressão de Poisson indicou que as principais variáveis meteorológicas foram significativamente relacionadas à abundância em cada local. Este estudo mostra que devido à preferência por gramíneas em estado vegetativo e às altas exigências de temperatura (30°C), M. latipes é uma espécie importante em regiões quentes, especialmente nas épocas de maior umidade. Além disso, mesmo em latitudes elevadas, durante os meses de verão, as populações podem aumentar rapidamente, podendo causar danos econômicos.

The Granulate Cutworm (Lepidoptera: Noctuidae): Biological Parameters Under Controlled Conditions, Host Plants, and Distribution in the Americas.

Feltia subterranea (Fabricius), commonly known as the granulate cutworm, is a common species of owlet moths (Noctuidae) of major agricultural importance, widely distributed in Nearctic and Neotropical regions. This study was conducted to determine the species biological parameters, gather information about its larval host plants, and assess the agricultural significance of this species in the Americas. The viability of the egg, larval, pupal stages, and prepupal period was 98, 98, and 100%, respectively, under laboratory conditions. The average duration of the egg, larval, pupal stages, and prepupal period was 3, 17, 4, and 13 d, respectively. All laboratory-reared larvae developed through five instars. The growth ratio was 1.93 for females and 1.85 for males. The duration of the larval stage was significantly longer in females than in males from the fourth instar. The duration of the pupal stage was significantly shorter in females than in males. When larval and pupal stage durations were combined, there were no significant differences in total development time as a function of sex. In total, 159 botanical taxa belonging to 41 families were recorded as host species for F. subterranea. The families with the greatest number of host species were Fabaceae (22), Poaceae (19), Asteraceae (16), Brassicaceae (13), Solanaceae (12), Amaranthaceae (7), Cucurbitaceae (7), and Malvaceae (5). It is noteworthy that the large number of native weeds used by F. subterranea as host plants could represent a significant source of infestation of crops in the agricultural landscape.

Biotic potential, fertility and life table of Spodoptera albula (Walker) (Lepidoptera: Noctuidae), under controlled conditions.

This study aimed to evaluate the biotic potential, life table parameters and fertility of Spodoptera albula (Walker, 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photo phase). The longevity, pre, post and oviposition periods, fecundity and fertility of 13 couples were evaluated. The longevity of females (13.500 days) was significantly higher than those of males (11.154 days). The mean durations of the pre, post and oviposition periods were 2.615, 1.769 and 9.385 days, respectively. The mean fecundity was 1.417.69 eggs and mean fertility was 1.340.401 larvae, per female. On average, females copulated 1, 231 times. A strong positive correlation was observed between the number of copulations and fecundity (r = 0.847, p <0.001), as well as a strong negative correlation between the number of copulations and the duration of the pre-oviposition period (r = -0.762, p = 0.002), and longevity (r = -0.788, p = 0.001). The biotic potential of S. albula was estimated at 8.768 x 1022 individuals / female / year. The net reproductive rate (Ro) was 353,904 times per generation and the mean generation time (T) was 37.187 days. The intrinsic rate of increase (rm) was 1,105, with a finite rate of increase (λ) of 3,019.

Immature stages of Spodoptera albula (Walker) (Lepidoptera: Noctuidae): developmental parameters and host plants.

This study aimed to detail the temporal and morphological parameters of the immature stages of Spodoptera albula (Walker 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase) and to gather information about their larval host plants. For this purpose, a new rearing method and artificial diet was employed and validated. The viability of the egg, larval, pupal and pre-pupal stages was 94.54, 97.33, 93.84 and 92.34%, respectively. The average duration of the egg, larval, pupal and pre-pupal stages was 4.14, 16.37, 1.69, and 9.34 days, respectively. During the larval stage, 80.85% of females and 93.99% of males passed through six and remaining through seven instars, with significant larval protandry. The larvae that developed through six and seven instars exhibited a mean growth rate of 1.58 and 1.48, respectively. Fifty five host plant species belonging to 29 families are listed. The female pupae were significantly larger, exhibiting protogyny. Both the rearing methods as well as the larval diet proved adequate, providing more detailled observations of the biological cycle, especially the larval stage, and resulting in an overall survival of almost 80%.