ABSTRACT
Abstract Sexual choice by male stink bugs is important because females that experience food shortages lay fewer eggs with lower viability compared with well-fed females. In this study, we investigated whether Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) males fed with a low-quality diet during its nymphal stage show selectivity for sexual partners resulting in high-quality progeny. Lightweight males and females were obtained from nymphs fed weekly with Tenebrio molitor L. (Coleoptera: Tenebrionidae) pupae. By contrast, heavyweight males and females were fed three times a week and received an extra nutritional source: cotton leaves, Gossypium hirsutum L. (Malvaceae). Lightweight males preferred to mate with heavy females (77.78 ± 14.69%), whereas heavyweight males did not discriminated between light or heavyweight females. Females mated with lightweight males showed similar levels of reproduction to those mated with heavyweight males. The results provide an indication of the importance of male and female body weight for sexual selection in Asopinae stink bugs.
Resumo A seleção sexual por machos de percevejos é importante porque fêmeas que passaram por escassez alimentar poem poucos ovos com baixa viabilidade em comparação com fêmeas bem alimentadas. Nesse estudo, investigamos se machos de Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) alimentados com dieta de baixa qualidade durante seu estágio ninfal apresenta seletividade por parceiras sexuais resultando em progênie de alta qualidade. Machos e fêmeas leves foram obtidos de ninfas alimentadas semanalmente com pupas de Tenebrio molitor L. (Coleoptera: Tenebrionidae). Em contraste, machos e fêmeas pesados foram alimentados três vezes por semana e receberam uma fonte nutricional extra: folhas de algodão, Gossypium hirsutum L. (Malvaceae). Machos leves preferiram acasalar com fêmeas pesadas (77,78 ± 14,69%), enquanto machos pesados não distinguiram fêmeas leves ou pesadas para acasalamento. Fêmeas que acasalaram com machos leves apresentaram níveis de reprodução semelhantes em comparação com aquelas acasaladas com machos pesados. Os resultados fornecem uma indicação da importância do peso corpóreo de machos e fêmeas para a seleção sexual em percevejos Asopinae.
Subject(s)
Animals , Male , Female , Body Weight , Heteroptera/physiology , Genetic Fitness , Reproduction , Heteroptera/growth & development , Heteroptera/genetics , Diet , Nymph/growth & development , Nymph/physiology , Nymph/geneticsABSTRACT
Platyscytus decempunctatus Carvalho is a small mirid living throughout its life cicle plant Solanum cernuum Vell. (Solanaceae). The internal morphology of P. decempunctatus was studied and found that the female has a telotrophic ovary with three ovarioles in the right ovary and five in the left one. In the male reproductive trait there is a well developed tubular accessory gland. The phytophagous feeding habitat of P. decempunctatus was confirmed by the observations of chlorophyll pigments in the gut of all dissected specimens. The tubular salivary glands and the Malpighian tubules were also discussed.
Platyscytus decempunctatus Carvalho é um mirídeo de pequeno porte que vive durante seu ciclo de vida em plantas de Solanum cernuum Vell. (Solanaceae). A morfologia interna de P. decempunctatus foi estudada revelando que fêmeas possuem ovário do tipo telotrófico com três ovaríolos no ovário direito e cinco no esquerdo. Nas estruturas reprodutivas dos machos existe uma glândula acessória tubular bem desenvolvida. A fitofagia de P. decempunctatus foi confirmada devido a observações de pigmentos de clorofila no intestino de todos os espécimes dissecados. As glândulas salivares em formato tubular e os túbulos de Malpighi também foram discutidos.
Subject(s)
Heteroptera/anatomy & histology , Heteroptera/geneticsABSTRACT
In Nysius californicus (family Lygaeidae, subfamily Orsillinae), a pest commonly known as the seed bug, the chromosome complement is 2n = 16 (12A + 2m + XY), testes are formed by seven seminiferous tubules covered by an orange-colored membrane, and spermatogenesis is cystic. At prophase, sex chromosomes are heteropycnotic and autosomes usually show a chiasma. At metaphase, sex chromosomes along with microchromosomes may be seen located at the center of a ring formed by the remaining autosomes. A characteristic specific of N. californicus was the presence of nucleolar material observed from the cystic cell to the completely differentiated spermatozoon.Variations in size, shape and location of the nucleolar material occur during this process, denoting a variable degree of activity in the different stages.
Subject(s)
Animals , Male , Heteroptera/cytology , Nucleolus Organizer Region , Seminiferous Tubules/cytology , Sex Chromosomes/physiology , Spermatogenesis/physiology , Heteroptera/genetics , MeiosisABSTRACT
Orcein staining of spermatocytes was used to study the meiotic behavior of holocentric chromosomes in three member of the genus Antiteuchus (commonly known as stink bugs). We describe and illustrate the karyotype of Antiteuchus mixtus, A. sepulcralis and A. macraspis which were cytogenetically characterized as having a diploid number of 2n = 14 and an XY sex chromosome system showing pre-reductional meiosis for autosomes and post-reductional meiosis for sex chromosomes. These species were also shown to have a long diffuse stage during meiotic prophase I and aberrant harlequin-type meiocytes. The chiasma frequency was also analyzed for two of the three species studied.