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 Hü bner, Spodoptera cosmioides (Walker), Spodoptera eridania (Stoll), and Spodoptera albula (Walker). In addition, Rachiplusia nu (Guené e) is one of the most common Plusiinae in the southern region of Brazil, encompassing the states of Paraná, Santa Catarina, and Rio Grande do Sul. The correct identiÞcation 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 (PCRÐRFLP) 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 ampliÞed using PCR and then sequenced. The Þve Lepidoptera species were distinguished by restriction enzymes Bpm I and MboI. 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.

Morphological Characterization of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae: Heliothinae)

“…Eggs are covered with secretions, scales, or simply devoid of coating. Eggs vary in size, shape, and structure (Peterson 1961(Peterson , 1964Gomez Rolim et al 2013). Egg morphology and oviposition behavior described herein for H. armigera are consistent with what has previously been observed in other species of Noctuidae.…”

Ultra‐structural and physico‐chemical characterization of eggs and egg hairs (setae) of the new invasive pest, fall armyworm,Spodoptera frugiperda(J. E. Smith) in India: A first report

“…Similarly, Korycinska (2012) reported the external morphological characters on the chorion of the eggs in some lepidopteran insect's viz., Autographa gamma , Helicoverpa armigera , Lacanobia oleracea , Mamestra brassicae , Spodoptera exigua , Spodoptera littoralis , Spodoptera litura , and not in S. frugiperda for early identification of quarantine pest species (Korycinska, 2012). Further, Gomez Rolim, Yano, Specht, Andrade, and Sosa‐Gomez (2013), described the eggs, shell architecture by SEM and documented the number of rosette petals, primary cells, number of secondary cells, number of ribs, and rosette diameter of the egg shells to distinguish three spodoptera species ( S. cosmioides , S. eridania , and S. albula ).…”

Lepidoptera (Insecta) associated with soybean in Argentina, Brazil, Chile and Uruguay

“…Alternatively, some studies has focused in species-level identification based on morphology of eggs, larvae, and pupae (e.g. PASSOA, 1991;POGUE, 2002;ANGULO et al, 2008;GOMEZ-ROLIM et al, 2013). Another tool is the use of molecular markers (GOMEZ-ROLIM et al, 2013).…”

“…PASSOA, 1991;POGUE, 2002;ANGULO et al, 2008;GOMEZ-ROLIM et al, 2013). Another tool is the use of molecular markers (GOMEZ-ROLIM et al, 2013). In all options, the literature describing morphological or molecular characterization of lepidopterons associated to soybean does not include all species.…”