Aspectos biológicos de Leucothyreus dorsalis Blanchard (Coleoptera, Scarabaeidae, Rutelinae)

Abstract

ABSTRACT. Biological aspects of Leucothyreus dorsalis Blanchard (Coleoptera, Scarabaeidae, Rutelinae). In Brazil there is a shortage of information on bioecology of most species of Scarabaeidae. The aim of this work was to study the biological aspects of Leucothyreus dorsalis Blanchard, 1850 in laboratory and field. The population dynamics of adults was evaluated from January, 2006, to December, 2007, with the use of light traps. Adults collected in the field were kept in plastic recipients containing soil and seedlings of Brachiaria decumbens Stapf, to obtain eggs and start the studies. All developmental stages were monitored and adults and immatures measured to get biometric data. 3,607 adults were collected and the population peaks occurred in November, 2006 and October, 2007, with averages of 145 e 241 individuals collected, respectively. The embryonic period took in the average 15.5 days, the 1 st instar 32.4 days, the 2 nd instar 38.9 days, the 3 rd instar 52.7 days, the pre-pupa 130.7 days, the pupa 23.5 days and the longevity of adults 18 days. The biological cycle was completed in 273.5 days, characterizing the specie as univoltine. From the first to the third instar it was observed an increasing of 4.5 times in the extension and 3.5 times in the width of the larvae. There was an increase of 53.1 times in the larval weight from the first to the third instar. The female pupae were significantly larger and heavier than the male ones. The adult females are larger than the adult males, however, they have similar weight.KEYWORDS. Biological cycle; population fluctuation; rhizophagous pests; Scarabaeoidea; white grubs. Blanchard, 1850 (Coleoptera, Scarabaeidae, Rutelinae). No Brasil existe uma escassez de informações sobre a bioecologia da maioria das espécies de Scarabaeidae. O objetivo do presente trabalho foi estudar os aspectos biológicos de Leucothyreus dorsalis Blanchard, 1850 em laboratório e a campo. A dinâmica populacional dos adultos foi avaliada de janeiro de 2006 a dezembro de 2007, com uso de armadilha luminosa. Adultos coletados em campo foram mantidos em recipientes de plástico contendo solo e mudas de Brachiaria decumbens Stapf, para obtenção de ovos e dar início aos estudos. Todos os estágios de desenvolvimento foram acompanhados e adultos e imaturos foram mensurados para obtenção de dados biométricos. Foram coletados 3.607 adultos e os picos populacionais de coleta ocorreram em novembro de 2006 e outubro de 2007, com média de 145 e 241 indivíduos coletados, respectivamente. O período embrionário durou em média 15,5 dias, o primeiro instar 32,4 dias, o segundo 38,9 dias, o terceiro 52,7 dias, a fase de pré-pupa 130,7 dias, a fase pupal 23,5 dias e a longevidade 18 dias. O ciclo biológico completou-se em 273,5 dias, o que caracteriza a espécie como univoltina. Verificou-se que do primeiro ao terceiro instar houve um aumento de 4,5 vezes no comprimento e de 3,5 vezes na largura das larvas. Observou-se um aumento de 53,1 vezes no peso larval do primeiro para o terceiro instar. As pupas das fêm...

Occurrence of adults and biological aspects of Geniates borelli Camerano (Coleoptera, Scarabaeidae, Rutelinae) in Aquidauana, MS, Brazil

“…The embryonic period of G. borelli was 17.9 days, longer than the durations of 13.8 days for P. cuyabana (Oliveira et al 1996), 13.2 for A. testaceipennis (Rodrigues et al 2008a), and 15.5 days for L. dorsalis (Rodrigues et al 2010b).…”

“…Rodrigues et al (2010b) found L. dorsalis eggs laid individually in soil chambers measuring 1.9 × 1.6 mm.…”

“…For L. dorsalis durations of the first, second and third instars were 32.4; 38.9; and 52.7 days, respectively (Rodrigues et al 2010b), while for P. cuyabana durations were 26.9; 34.4; and 80.8 days for the first, second, and third instars, respectively (Oliveira et al 1996).…”

“…Each container was wrapped in voile fabric and received two insect pairs, so as to allow plant growth and restrain the adults. The containers were inspected weekly for the presence of eggs as well as to start the biology studies; this methodology was used by Rodrigues et al (2010b).…”

“…In the subfamily Rutelinae studies have been conducted only for Anomala testaceipennis Blanchard, 1856 and Leucothyreus dorsalis Blanchard, 1850 (Rodrigues et al 2008a(Rodrigues et al , 2010b however, their biological aspects are unknown (Morón 2004). Therefore, this study aimed to investigate the population dynamics and biological aspects of this species.…”