Viviana Cauduro Matesco

Imaturos de pentatomideos (Hemiptera, Heteroptera): morfologia e biologia de Acrosternum obstinatum

The morphological characteristics of the egg and five immature stages of Acrosternum obstinatum (Stal, 1860), fed on passion fruit, are described and illustrated. Biological data are also provided.

Morphology of the immatures and biology of Chinavia longicorialis (Breddin) (Hemiptera: Pentatomidae)

Chinavia longicorialis (Breddin) is recorded only in Brazil, Argentina and Uruguay on host plants of at least three different families. Adults and nymphs were reared under standard controlled conditions (24 +/- 1 degrees C; 70 +/- 10% RH; 12hL:12hD), and fed on green beans (Phaseolus vulgaris L.). Eggs and first instars of C. longicorialis are very similar to those of other species of Chinavia; however, the presence of orange maculae at the thoracic pleura is exclusive of first instars of C. longicorialis. Third to fifth instars have abdominal maculae divided by pseudo-sutures, a diagnostic feature of C. longicorialis nymphs. Light and dark morphs were observed for third, fourth and fifth instars. Head width measurements did not overlap between consecutive instars. The most frequent size of an egg clutch was 14; we suggest the adoption of the mode as the best and useful estimate of the egg clutch size for Pentatomidae. Average duration of the immature stages (egg to adult) was 39.4 +/- 3.20 days. The high mortality observed from second to fifth instar (82.4%) and the lack of reproduction of the second generation indicate that green beans are unsuitable to proper development and reproduction of C. longicorialis by itself.

Immature stages of Chinavia musiva (Berg, 1878): a unique pattern in the morphology of Chinavia Orian, 1965 (Hemiptera, Pentatomidae)1

Specimens of Chinavia musiva were collected in Parque Estadual do Espinilho (Barra do Quaraí County, RS, Brazil). Insects were reared under controlled conditions (24±1°C; RH 70±10%; 12h L:12h D), and fed on green beans (Phaseolus vulgaris L.). Eggs of C. musiva differ from the pattern observed in other species of the genus due to chorion colour and surface, and aero‐micropylar processes, number and shape. Exclusive features of the species in the nymphal stage are head and thorax dull; variegated pattern of abdomen, and openings of the scent glands in conspicuous tubercles. Developmental time was, on average, 52 days; females laid more frequently egg masses with 14 or 42 eggs. Females collected from the field as nymphs exhibited higher reproductive performance than females reared on green beans as nymphs and adults, suggesting that wild hosts could be essential for the species life cycle. 1. Contribution n°. 542 of Departamento de Zoologia, UFRGS.

Descrição dos estágios imaturos e biologia de Chinavia pengue (Rolston) (Hemiptera, Pentatomidae)

Adults of Chinavia pengue (Rolston, 1983) were collected in Garopaba county, SC, and used to establish a laboratory culture under controlled conditions (24 ± 1°C; 70 ± 10% RH; 12hL:12hD). Adults and nymphs were fed with green beans (Phaseolus vulgaris L.). Eggs of C. pengue follow the pattern of coloration, chorion sculpture, color and shape of the aero-micropylar processes described to other neotropical Chinavia species. The first instar has the dorsal macula of the head and thorax characteristic of Chinavia species. In C. pengue, this macula is orange-red, and the abdominal maculae (4+4 lateral maculae and one median) are white. From second to fifth instars diagnostic characteristics are orange-red maculae at pro and mesothorax, and at middle of abdominal lateral plates. There was no overlapping of the head-capsule measurements between the five instars of C. pengue. Each female laid an average of 15.9 ± 4.18 egg masses and 218.8 ± 48.60 eggs; there was a marked peak at 14 eggs per egg mass. Mean egg fertility was 70.0% ± 19.01; mortality in the second to fifth stadium was 1.6% ± 4.49. Sex ratio was 1 male: 1 female. The mean duration of the immature stage (egg to adult) was 45.7 ± 2.99 days.

Revision of the genus Alkindus Distant (Hemiptera: Heteroptera: Thyreocoridae: Corimelaeninae)

The neotropical genus Alkindus Distant is revised based on morphological characters (general morphology, including the external scent efferent system and leg structures, and external genital morphology). The male of Alkindus crassicosta Horvath is here described for the first time. Illustrations, an adapted key to species, and a compiled list of plants associated with both species are provided. Distribution records are expanded to include Guatemala and Brazil (Roraima) for Alkindus atratus Distant and Brazil (Santa Catarina) for A. crassicosta.

Negro Bugs (Thyreocoridae)

The Thyreocoridae, usually known as “negro bugs,” includes 212 species in 12 genera distributed in two subfamilies Thyreocorinae (seven species in three genera) which are not represented in the neotropics and Corimelaeninae (205 species in nine genera) with a worldwide distribution. Relatively small and dark colored, often shiny, this is a poorly studied family within Pentatomoidea and its relationships still being debated. They are exclusively herbivorous, and, at least, 23 Mexican and Neotropical species have some record of associated plant. Besides that, in the literature, there is no information about damage caused by these bugs. Immature stages are known only for eight species occurring in Mexico and Neotropical region, including descriptions of eggs and/or nymphs and/or life history. The only known key for the Neotropical representatives of the family is that found in McAtee and Malloch (Ann Carnegie Mus 21:191–411, 1933).

External morphology of the immature stages of Vatiga manihotae (Hemiptera: Tingidae) with comments on ontogenesis

Abstract Vatiga (Hemiptera: Tingidae) species show preference for Cassava plants (Euphorbiaceae: Manihot), an important food source in the American tropics. Infestations of Cassava by Vatiga can cause serious harvest losses. Information on immature stages morphology can aid in early identifications of crop pests and provide data for use in phylogenetic analyses; thus, we describe and illustrate the external morphology of all life stages of Vatiga manihotae using optical and scanning electron microscopies. Eggs are laid inserted in the leaf blade, are whitish and oblong, with smooth chorion. In the larvae, the tegument is covered by hemispherical projections, which remain the same and become denser through ontogenesis. Dorsal surface of head and lateral margins of body with tubercles; from the second through the fifth instars the cephalic and lateral tubercles maintain the same structure, only adding setae along its surfaces. The cephalic tubercles of V. manihotae nymphs are more complex than those of the adults, as on the latter the cephalic tubercles lack setae. As suggested by literature, our discoveries fit the intermediate clades scenario of the ontogenetic pathway in which larvae have outgrowths and adults are simple, suggesting that brood protection is absent and larval protection by secretions may be present.

Morphology of the Nymphs of Euschistus convergens (Hemiptera: Pentatomidae)

Abstract Nymphs of Euschistus (Mitripus) convergens (Herrich-Schaffer) (Hemiptera: Pentatomidae) are described using light and scanning electron microscopy. In the 1st instar, the integument and the lateral margins of the body are smooth, the dorsal abdominal scent glands bear a rounded peritreme with cuticular valve, and the evaporatorium surface bears pointed projections. From the 2nd to the 5th instars, the integument surface is granulated, the lateral margins of the body are serrated, the dorsal abdominal scent glands bear a spout-shaped peritreme with a cuticular valve, and the evaporatorium surface is reticulated. The overall morphology of E. convergens nymphs resembles the morphology of nymphs of other Euschistus species.