Alexandre Specht

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%.

Diversidade dos noctuídeos (Lepidoptera, Noctuidae) em Salvador do Sul, Rio Grande do Sul, Brasil

Diversity of owlet-moth (Lepidoptera, Noctuidae) in Salvador do Sul, Rio Grande do Sul, Brazil. The purpose of this paper is to describe the Noctuidae community in Salvador do Sul, Rio Grande do Sul. Light traps captured the insects of this research. The quantitative data were collected through weekly sampling, during one year (1994-1995); the qualitative data were collected through non-systematic sampling, during four consecutive years. The community characterization was based on the richness, abundance, specific constancy, diversity indices and abundance distribution; also total richness estimates were calculated, by nonparametric statistical procedures. In the systematized collecting there were captured 4017 noctuids of 108 species, distributed in 14 subfamilies; in the non-systematized, another 189 additional species and two subfamilies. Amphipyrinae, Hadeninae and Ophiderinae had the largest species richness. The more constant species were noctuids of great economic importance; the accessories were related to specific vegetable groups; the accidentals have their host unknown. The accessories and accidental species were captured more in spring and summer; also in these periods were measured the highest values of richness, abundance and diversity. There was no fit between observed/calculated log normal and log series distribution models. The 2nd order Jackknife and Michaelis-Menten equation procedures estimated that the total richness values were close to the total number of the species in the studied area.

Arctiinae (Lepidoptera, Arctiidae) coletados em unidades de conservação estaduais do Rio Grande do Sul, Brasil

Arctiinae (Lepidoptera, Arctiidae) coletados em unidades de conservacao estaduais do Rio Grande do Sul, Brasil. O presente estudo foi realizado com o objetivo de analisar a composicao das comunidades de Arctiinae no Parque Estadual do Espigao Alto (Barracao), Parque Estadual de Rondinha (Sarandi), Parque Estadual do Turvo (Derrubadas) e na Reserva Biologica de Ibirapuita (Alegrete). Dez armadilhas luminosas foram utilizadas para coletar os lepidopteros, de novembro de 2000 a fevereiro de 2001, amostrando-se uma noite em cada local. Os lepidopteros foram identificados aos niveis de subfamilia, tribo e, quando possivel genero e especie. Obteve-se um total de 5.969 arctiineos pertencentes a 137 morfo especies, distribuidos em seis tribos.

Vertical and temporal variability in the probability of detection of fruit‐feeding butterflies and moths (Lepidoptera) in tropical forest

One important source of variation present in all biodiversity sampling protocols is species detection probability (i.e. the probability of observing a species, given that it is present at a site). In tropical forests, many species have very low probability of detection, and thus they can be easily overlooked. Measuring the detection probability (detectability) of these species is important to determine the sampling effort required to accurately record them. In the present study, the variation of detectability of fruit‐feeding butterflies and moths between strata (understory vs. canopy), temporally across sampling months, and in relation to observed abundance were examined in the Amazon and Atlantic forests using models of logistic regression. These results enabled the estimation of the sampling effort required to detect a given fraction of the total assemblage. Species detectability was positively correlated with observed abundance for both butterflies and moths. In the Amazon, most species were more detectable in a specific stratum (canopy or understory). Biblidinae, Charaxinae and Satyrini showed temporal variation in detection probability in Atlantic Forest, with distinct peaks during July–August, November, and March. In contrast, Brassolini and Coeini showed peak detectability in January and March, respectively. The vertical and temporal variation in detection probability means that sampling effort must be applied strategically to the correct seasons and strata to improve the accuracy of results. The estimated minimum sampling effort to detect 70% of the species present in these tropical forests is 428 trap‐days in Atlantic Forest and 1435 trap‐days in the Central Amazon forest.

Immature Stages of Spodoptera eridania (Lepidoptera: Noctuidae): Developmental Parameters and Host Plants

Abstract This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25 ± 1°C, 70 ± 10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre–pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female’s development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania , mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae.

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.

Morphological and Molecular Characterization of the Eggs of Some Noctuid Species Associated with Soybean in Brazil

ABSTRACT The most important species of Lepidoptera that attack soybean, in descending order of importance, are Chrysodeixis includens (Walker), Anticarsia gemmatalis Hübner, Spodoptera cosmioides (Walker), Spodoptera eridania (Stoll), and Spodoptera albula (Walker). In addition, Rachiplusia nu ( Guenée ) is one of the most common Plusiinae in the southern region of Brazil, encompassing the states of Paraná, Santa Catalina, and Rio Grande do Sul. The correct identification of these species is essential for choosing the appropriate control measures, as they differ in their susceptibility to insecticides and biological control agents. To distinguish Lepidoptera species commonly found in Brazil, the eggshells of all these species were morphologically characterized by scanning electron microscopy. Diagnostic characters for differentiating species include shape of rosette petals, number of primary cells, number of secondary cells, number of ribs, and rosette diameter. Also, a molecular diagnostic method using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis was developed to distinguish noctuid species commonly found in Brazil. A 658-bp region of the mitochondrial DNA cytochrome oxidase subunit I gene was amplified using PCR and then sequenced. The five Lepidoptera species were distinguished by restriction enzymes Bpm I and Mbol. RFLPs produced by Bpm I endonuclease were useful to discriminate species from within Spodoptera (S. cosmioides, S. eridania, and S. albula) and R. nu from C. includens. However, Bpm I did not digest the amplicons from S. eridania and C. includens, which were discriminated by RFLP patterns produced by the restriction enzyme MboI. PCR-RFLP can be performed in a short period, and it is useful to distinguish the most important Brazilian Lepidoptera soybean pests.

High susceptibility and low resistance allele frequency of Chrysodeixis includens (Lepidoptera: Noctuidae) field populations to Cry1Ac in Brazil

BACKGROUND The soybean looper (SBL), Chrysodeixis includens (Walker), is one of the most important soybean pests in Brazil. MON 87701 × MON 89788 soybean expressing Cry1Ac has been recently deployed in Brazil, providing high levels of control against the primary lepidopteran pests. To support insect resistance management (IRM) programmes, the baseline susceptibility of SBL to Cry1Ac was assessed, and the resistance allele frequency was estimated on the basis of an F2 screen. RESULTS The toxicity (LC50 ) of Cry1Ac ranged from 0.39 to 2.01 µg mL(-1) diet among all SBL field populations collected from crop seasons 2008/09 to 2012/13, which indicated approximately fivefold variation. Cry1Ac diagnostic concentrations of 5.6 and 18 µg mL(-1) diet were established for monitoring purposes, and no shift in mortality was observed. A total of 626 F2 family lines derived from SBL collected from locations across Brazil during crop season 2014/15 were screened for the presence of Cry1Ac resistance alleles. None of the 626 families survived on MON 87701 × MON 89788 soybean leaf tissue (joint frequency 0.0004). CONCLUSIONS SBL showed high susceptibility and low resistance allele frequency to Cry1Ac across the main soybean-producing regions in Brazil. These findings meet important criteria for effective IRM strategy.

Biological aspects of Autoplusia egena (Guenée) (Lepidoptera: Noctuidae, Plusiinae)

Autoplusia egena (Guenée) is a moth distributed throughout the Western hemisphere. The larvae have already been found feeding on several different plant families, including important crops such soybeans and beans. To contribute to the knowledge of its biology in laboratory conditions, and considering the duration and the morphometry of each development stage, a laboratorial rearing was accomplished at 25 +/- 1 degrees C, 70 +/- 10% RH and 14h photophase. The larvae were fed with black bean leaves and the adults were fed with a honey solution at 10%. The results, expressed by the mean (+/- SE), for the periods of each stage were: egg 3.0 +/- 0.00 d; larva 15.7 +/- 1.25 d; pre-pupa 1.9 +/- 0.05 d; pupa 8.8 +/- 0.09 d and adult: longevity 12.1 +/- 0.95 d, pre-oviposition 5.4 +/- 0.50 d, oviposition 6.3 +/- 1.10 d and post-oviposition 1.4 +/- 0.87 d. The larvae went through five instars, for which the mean width of the cephalic capsules were 0.302 +/- 0.001 mm; 0.500 +/- 0.003 mm; 0.854 +/- 0.008 mm; 1.424 +/- 0.011 mm and 2.744 +/- 0.053 mm. The average length, width, and weight of the pupae were 16.965 +/- 0.003 mm, 4.674 +/- 0.040 mm and 0.217 +/- 0.003 g, respectively.

Battle in the new world: Helicoverpa armigera versus Helicoverpa zea (Lepidoptera: Noctuidae).

The corn earworm Helicoverpa zea (Boddie) and the old world bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are allopatric species and occur in important agricultural crops. In maize, both species tend to infest the ear. The introduction of H. armigera in Brazil has created a new scenario, where these Helicoverpa species might cohabit and interact with one another, affecting the prevalence of each species in the agroecosystem, integrated pest management, and insect resistance management. In this study, larval occurrence and proportion of these species in maize was assessed in three regions of Brazil during three crop seasons. Interaction between the species was evaluated in interspecific and intraspecific scenarios under laboratory and field conditions. Helicoverpa zea was predominant in Rio Grande do Sul and the Planaltina, DF (central Brazil). In western Bahia, H. zea was predominant in the first collection, but approximately equal in number to H armigera in the second crop season. Both species exhibit high cannibalism/predation rates, and larval size was the primary factor for larval survival in the interaction studies. Larva of H. zea had higher survival when interacting with H. armigera, indicating that H. zea has an advantage in intraguild interactions with H. armigera in maize. Overall, the results from this study indicate that maize might play a role as a source of infestation or a sink of insecticide or Bt protein unselected H. armigera populations, depending on the H. zea:H. armigera intraguild competition and adult movement in the landscape.