Biotic potential and reproductive parameters of Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) in the laboratory / Potencial biótico e parâmetros reprodutivos de Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) em laboratório

Abstract In this study we evaluate the biotic potential and reproductive parameters of Spodoptera cosmioides (Walker, 1858) under controlled conditions (25 ± 1 °C, 70 ± 10% RH and 14 hour photophase). Females, on average, (14.433 days) did not live significantly longer than their male counterparts (13.100 days). The mean durations of the pre-oviposition, oviposition and post-oviposition periods were 2.767, 10.600 and 1.067 days, respectively. The mean fecundity of females was 5,073.533 eggs and the mean fertility was 5,021.027 larvae. On average, females copulated 1.167 times. Fecundity was positively correlated with the number of copulations (r = 0.583, P <0.001). The number of copulations, however, was negatively correlated whit the duration of the pre-oviposition (r = -0.560, P = 0.007) and oviposition (r = -0.479, P = 0.048) periods, and overall longevity (r = -0.512, P = 0.031). The biotic potential was estimated at 6.547 x 1021 individuals/female/year. The net reproductive rate (Ro) was 2,193.722 times per generation and the mean generation time (T) was 46.407 days. The intrinsic rate of increase (rm) was 0.166, with a finite rate of increase (λ) of 1.180, per week.

Resumo Neste estudo avaliamos o potencial biótico e parâmetros reprodutivos de Spodoptera cosmioides (Walker, 1858) em condições controladas (25 ± 1 °C, 70 ± 10% UR e 14 horas de fotofase). Em média, as fêmeas (14,433 dias) não viveram significativamente mais do que os machos (13,100 dias). A duração média dos períodos de pre-oviposição, oviposição e pós-oviposição foram 2,767; 10,600 e 1,067 dias, respectivamente. A fecundidade média das fêmeas foi de 5.073,533 ovos e a fertilidade média foi de 5.021,027 larvas. Em média, as fêmeas copularam 1,167 vezes. A fecundidade correlacionou-se positivamente com o número de cópulas (r = 0,583; P <0,001). Entretanto, o número de cópulas correlacionou-se negativamente com a duração dos períodos de pré-oviposição (r = -0,560; P = 0,007), oviposição (r = -0,479; P = 0;048) e a longevidade (r = -0,512; P = 0,031). O potencial biótico foi estimado em 6,547 x 1021 indivíduos/fêmea/ano. A taxa líquida de reprodução (Ro) foi de 2.193,722 vezes por geração e o tempo médio de cada geração (T) foi de 46,407 dias. A taxa intrínseca de crescimento (rm) foi 0,166, com uma taxa finita de aumento (λ) de 1,180, por semana.

Feltia submontana (Noctuidae, Noctuinae): Redescription, Taxonomy, Life Cycle, and Spatial Distribution of a Neglected South American Potential Pest Species.

Feltia submontana (Köhler, 1961) is redescribed based on specimens from Northwestern Argentina and Central and Southeastern Brazil. Taxonomic comments, photographs of the adults, characters of taxonomic importance, and illustrations of structures of the labial palpus, legs, and male and female genitalia are provided. The species is compared with similar-looking and supposedly closely related species, such as F. hispidula (Guenée, 1852) and F. lilacina (Zerny, 1916). The species, originally described for Argentina, is reported for Brazil for the first time. Most Brazilian specimens come from the "Cerrado" but also from Southeastern Atlantic Forests. The life cycle of F. submontana specimens collected in Planaltina, Distrito Federal, Brazil, is described; the species probably has only a single generation per year and imagines are on the wing in the late autumn and early winter months; the last instar prepupa and pupa pass through aestival diapause. The abundance of F. submontana relative to other species of Agrotis Ochsenheimer, 1816, and Feltia Walker, 1856, in the above-cited locality is accessed through 4 years of standardized collecting with light trap; the species is the second most abundant species of these genera in the area, with about one fifth of the captures, second only to A. ipsilon (Hufnagel, 1766), with about two thirds of the captures, and about two times more abundant than F. subterranea (Fabricius, 1794); the latter two are regarded as important pest species in South America.

Spodoptera marima: a New Synonym of Spodoptera ornithogalli (Lepidoptera: Noctuidae), with Notes on Adult Morphology, Host Plant Use and Genetic Variation Along Its Geographic Range.

Spodoptera marima (Schaus, 1904) and Spodoptera ornithogalli (Guenée, 1852) are noctuid moths recognized for their economic importance in the New World. Historically, they have been considered cryptic species, being supposedly differentiated from each other by the absence of sexual dimorphism in S. marima, subtle differences in coloration on the hindwings and scale tufts of the ovipositor and the shape of male valva. The species are allopatric: North and Central America for S. ornithogalli and South America for S. marima. Previous phylogenetic studies using multilocus DNA sequences including a few specimens of S. marima suggested these species merge into a single clade. Here, we performed a comparative analysis to elucidate further their taxonomic status, using specimens of S. marima from various localities in Brazil. These species were recovered in the phylogenetic analysis as consistently mixed with each other in a major well-supported clade within Spodoptera. The existence of a spatial pattern for genetic structure was not clearly supported when two biogeographic regions (Neotropics and Neartic) were taken in separation; however, an individual-level isolation by distance was significant. The morphological characters traditionally used to differentiate the species were also not consistent. Therefore, we now consider S. marima a new junior synonym of S. ornithogalli. Results on host plant use demonstrated that it is a polyphagous species using more than 200 plants, which may mediate phenotypic variation along its geographical range.

Biotic potential and reproductive parameters of Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) in the laboratory.

In this study we evaluate the biotic potential and reproductive parameters of Spodoptera cosmioides (Walker, 1858) under controlled conditions (25 ± 1 °C, 70 ± 10% RH and 14 hour photophase). Females, on average, (14.433 days) did not live significantly longer than their male counterparts (13.100 days). The mean durations of the pre-oviposition, oviposition and post-oviposition periods were 2.767, 10.600 and 1.067 days, respectively. The mean fecundity of females was 5,073.533 eggs and the mean fertility was 5,021.027 larvae. On average, females copulated 1.167 times. Fecundity was positively correlated with the number of copulations (r = 0.583, P <0.001). The number of copulations, however, was negatively correlated whit the duration of the pre-oviposition (r = -0.560, P = 0.007) and oviposition (r = -0.479, P = 0.048) periods, and overall longevity (r = -0.512, P = 0.031). The biotic potential was estimated at 6.547 x 1021 individuals/female/year. The net reproductive rate (Ro) was 2,193.722 times per generation and the mean generation time (T) was 46.407 days. The intrinsic rate of increase (rm) was 0.166, with a finite rate of increase (λ) of 1.180, per week.

Biotic Potential and Life Table of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) from Three Brazilian Regions.

This study aimed to evaluate the biotic potential and life table of individuals of Helicoverpa armigera (Hübner) from different host plants (citrus, corn, and cotton) and Brazilian states (São Paulo, Distrito Federal, and Bahia) in artificial diet, under laboratory conditions (25 ± 1°C, 70 ± 10% RH, 14 h photophase). The longevity, pre-, post- and oviposition periods, fecundity, and fertility of 15 mating pairs per origin were evaluated. We also compared the reproductive parameters of each group of insects (São Paulo (SP), Distrito Federal (DF), and Bahia (BA)), including the net reproductive rate (Ro), mean generation time (T), intrinsic rate of increase (r m), and finite rate of increase (λ). Microsatellite analysis from individuals collected in different locations and host plants did not show differences among the parental insects. It was verified that parental progeny collected in cotton fields from Bahia had a higher biotic potential, a higher reproductive rate (Ro), and a better fecundity compared to the insects from remaining regions. The life table charts indicate that the highest values for the reproductive parameters of the Bahia progeny are associated with higher specific fertility, particularly in early adulthood. The greatest biotic potential of the Bahia progeny may be due to increased selection pressure from the insecticide used (organophosphate and pyrethroid) on cotton crops compared to that of other crops, as well due to the massive adoption of Bt cotton-producing areas of that state from 2013 outbreaks.

Reproductive potential of Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) in the laboratory: effect of multiple couples and the size / Potencial reprodutivo de Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) em laboratório: efeito de múltiplos casais e do tamanho

Abstract This study aimed to evaluate the effect of keeping three couples in the same cage, and the size of adults emerged from small, medium-sized and large pupae (278.67 mg; 333.20 mg and 381.58 mg, respectively), on the reproductive potential of S. eridania (Stoll, 1782) adults, under controlled conditions (25 ± 1 °C, 70% RH and 14 hour photophase). We evaluated the survival, number of copulations, fecundity and fertility of the adult females. The survival of females from these different pupal sizes did not differ statistically, but the survival of males from large pupae was statistically shorter than from small pupae. Fecundity differed significantly and correlated positively with size. The number of effective copulations (espematophores) and fertility did not vary significantly with pupal size. Our results emphasize the importance of indicating the number of copulations and the size of the insects when reproductive parameters are compared.

Resumo Este estudo objetivou avaliar o efeito de confinar três casais em cada gaiola e o tamanho de adultos emergidos de pupas pequenas, medias e grandes (278,67 mg, 333,20 mg e 381,58 mg, respectivamente), sobre o potencial reprodutivo de S. eridania (Stoll, 1782), em condições controladas (25 ± 1 °C, 70% UR e 14 horas de fotofase). Avaliou-se a sobrevivência, o número de cópulas, fecundidade e fertilidade dos adultos. A sobrevivência não diferiu significativamente entre fêmeas provenientes de pupas de diferentes tamanhos, mas os machos oriundos de pupas grandes tiveram sobrevivência significativamente menor que os demais tamanhos. A fecundidade diferiu significativamente e correlacionou-se positivamente com o tamanho. O número de cópulas (espematóforos) e a fertilidade não variaram em função do peso pupal. Os resultados enfatizam a importância de indicar o número de cópulas e o tamanho dos insetos estudados para que comparações entre os parâmetros reprodutivos possam ser efetuadas.

Reproductive potential of Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) in the laboratory: effect of multiple couples and the size.

This study aimed to evaluate the effect of keeping three couples in the same cage, and the size of adults emerged from small, medium-sized and large pupae (278.67 mg; 333.20 mg and 381.58 mg, respectively), on the reproductive potential of S. eridania (Stoll, 1782) adults, under controlled conditions (25 ± 1 °C, 70% RH and 14 hour photophase). We evaluated the survival, number of copulations, fecundity and fertility of the adult females. The survival of females from these different pupal sizes did not differ statistically, but the survival of males from large pupae was statistically shorter than from small pupae. Fecundity differed significantly and correlated positively with size. The number of effective copulations (espematophores) and fertility did not vary significantly with pupal size. Our results emphasize the importance of indicating the number of copulations and the size of the insects when reproductive parameters are compared.

Immature Development of Spodoptera dolichos (Fabricius) (Lepidoptera: Noctuidae).

We provide detailed temporal and morphological parameters of the immature stages of Spodoptera dolichos (Fabricius) larvae fed on artificial diet under controlled conditions (25 ± 1 °C, 70 ± 10% RH, and 14 h photophase). The viability of the egg, larval, pupal, and prepupal stages was 97.5%, 97.0%, 93.1%, and 98.9%, respectively. The average duration of the egg, larval, prepupal, and pupal stages was 5.0, 23.4, 3.2, and 21.5 days, respectively. Females took longer at the larval stage than males, with 10.5% of them having seven instars. The growth rate of female larvae that developed through six and seven instars was 1.72 and 1.54, respectively. Female pupae were significantly larger, exhibiting slower development than males.

Biological aspects of Tiracola grandirena (Herrich-Schäffer, 1868) (Lepidoptera: Noctuidae): a polyphagous armyworm.

We studied the biology of Tiracola grandirena (Herrich-Schäffer, 1868) (Lepidoptera: Noctuidae: Hadeninae) at 25 ± 1 °C, 70 ± 10% RH and 14 hours of photo phase. Three experiments, using 150 larvae each, were conducted for the larval stage. In the first, used to assess the duration and survival of all stages, insects were reared individually and fed an artificial diet (Grenee). In the second, individuals were also reared separately, but were fed leaves of 10 plants from different families. In the third, the larvae were not individualised, the food plants were rotated such as to provide three plant species every 48 hours. In the first experiment, the viability of the eggs, larvae, pupae and prepupae was 91.9, 94.7, 32.49 and 43.5%, respectively. The average duration of the egg, larvae, prepupae, pupae and adult were 6.0, 25.3, 25.7, 21.4 and 12.7 days, respectively. The prolonged prepupal period indicates that T. grandirena can develop larval (prepupal) diapause. The results of the experiments with different host plants showed that T. grandirena is polyphagous at species, population and individual level.