ABSTRACT
ABSTRACT The garden fleahopper, Microtechnites bractatus (Say) (Hemiptera: Miridae), is associated with several cultivated plant species and, despite its economic importance, little is known about its development and performance in such hosts. We described here, the morphology of immature stages, and evaluated the biology of M. bractatus in beans, potatoes, white clover, alfalfa, and wheat. The bioassays were carried out in the laboratory under controlled temperature (25±2ºC), humidity (UR70±15%), and photoperiod (12L:12D). The eggs of M. bractatus are elongated and slightly curved, without respiratory projections and light yellow in color, becoming dark at the end of the incubation period. Nymphs present an oval-shaped body, a reddish color that intensifies along with the development and dimorphic wing pads in the fifth instar. In the bioassays, the host plants influenced the biological aspects of M. bractatus, both in the immature and adult stages. Nymph survival was higher in clover and alfalfa, while in wheat, it was lower. Clover-fed insects had the longest longevity. The fecundity parameters and egg viability were favored in insects that fed on clover and alfalfa. The fertility life table showed that feeding M. bractatus with clover provides a higher net reproduction rate (R0) and a higher finite ratio of population increase (ʎ). This study contributes to bioecological and behavioral studies on M. bractatus and provides data for the recognition and characterization of individuals in the immature stage.
ABSTRACT
ABSTRACT Diabrotica speciosa (Germar) and Diabrotica viridula F. (Coleoptera: Chrysomelidae) are the two most abundant species of the genus in South America, and belong to the fucata and virgifera groups, respectively. Here, we characterize the dimorphism of the setae present on the basitarsi of males and females of these species. Dimorphism was confirmed in both species, and it was related to the presence of adhesive setae exclusively in males, which possess these structures on the basal tarsomeres of the pro- and mesothoracic legs.
ABSTRACT
ABSTRACT Liogenys fusca is a rizophagous insect pest in various crops of economic importance in Brazil. Here we investigated the morphology of immature stages and mating behavior of this species. The redescription of the 3rd instar larvae of L. fusca in this work allows identification and registration of occurrence independently of adults, which occur sporadically in a certain period of the year. Male and female of L. fusca remained confined in the soil during the day and exited between 19:00 and 23:30 h. The copulations occurred between 19:30 and 21:00 h, and were characterized by a typical behavioral sequence. Copulation durations in L. fusca lasted on average 512.23 s. Adults were observed feeding before the copulations on leaves and inflorescences of plant species belonging to the family Anacardiaceae, Myracrodruon urundeuva, Schinus terebinthifolius, Astronium fraxinifolium and Anacardium occidentale.
ABSTRACT
A study on the biology of Utetheisa ornatrix reared on the artificial diet, was conducted to determine the thermal requirements in each development stage. The aim was to find out the thermal regions in the São Paulo state where the pest could develop on Crotalaria spp. The insects were reared on an artificial diet based on the white beans and yeast. U. ornatrix thermal requirements were tested at 18, 20, 22, 25, 28, 30, and 32ºC 70±20% RH, and 14-h photophase. Lower threshold temperatures (TT) and thermal constants (K) for the egg, larval and pupal stages were 12.7ºC and 51.2 GDD, 13.5ºC and 290.9 GDD, 13.8ºC and 108.4 GDD, respectively; TT and K values for the biological cycle were 13.8ºC and 436.3 GDD.
Estudou-se a biologia de Utetheisa ornatrix em dieta artificial, visando a determinação das exigências térmicas dos diferentes estágios de desenvolvimento, numa tentativa de avaliar as regiões do estado de São Paulo em que a praga tem maiores condições de se tornar problema para Crotalaria spp. Foram criados insetos em dieta artificial à base de feijão e levedura de cerveja. Para a determinação das exigências térmicas de U. ornatrix foram utilizadas as temperaturas de 18, 20, 22, 25, 28, 30 e 32ºC, umidade relativa de 70 ± 20% e fotofase de 14 horas. Os limiares térmicos inferiores de desenvolvimento (Tb) e as constantes térmicas (K) para os estágios de ovo, lagarta e pupa foram de 12,7ºC e 51,2 GD, 13,5ºC e 290,9 GD, 13,8ºC e 108,4 GD, respectivamente, resultando em valores de Tb e K para o ciclo biológico (ovo-adulto) de 13,8ºC e 436,3 GD. O inseto pode dar até 10 gerações anuais nas regiões em que Crotalaria spp. é mais importante para o estado de SP.