ABSTRACT
Abstract In Brazil, there are several species of the genus Leucothyreus Macleay, 1819 occurring throughout the country; however, there are only a few studies describing their biological aspects, times of occurrence, associations of adults and juveniles with native or cropped plants, as well as their mating behavior. Thus, this study aimed to assess the mating behavior of Leucothyreus marginaticollis Blanchard, 1843. The study took place in an experimental area of the State University of Mato Grosso do Sul, in Aquidauana, MS, Brazil. Firstly, we sampled adult insects using light traps, from October to November 2013. Simultaneously, we registered the flight period in the field. Afterward, in the laboratory, males and females were separated and then combined into couples for observations of the mating steps. A large number of the adults mated, which lasted on average 22.71 min and occurred from 7 to 11 pm. After mating, part of the males released the females and the other part remained attached to them, which must have happened as an attempt to inhibit other males from mating with them. Moreover, a few females refused to mate with the established male, reinforcing the fact that the pairing of couples occurs after chemical identification among adults. In the field, the largest amount of adults was collected from 8 to 10 pm. Regarding eating habits, adults feed mostly on acerola leaves and flowers (Malpighia emarginata DC, Malpighiaceae), mastic gum leaves (Myracrodruon urundeuva Allemão, Anacardiaceae), grapes (Vitis vinifera L., Vitaceae), apples (Malus domestica Borkh., Rosaceae), and bananas (Musa sp. L., Musaceae). To the end of the experiment, we could clarify the mating steps of L. marginaticollis in order to assist in further extraction and identification of sexual pheromone.
Resumo No Brasil várias são as espécies de Leucothyreus Macleay, 1819 que ocorrem nas diferentes regiões, entretanto, poucos são os trabalhos que descrevem os aspectos biológicos, épocas de ocorrência, associação de adultos e imaturos com plantas nativas ou cultivadas, e comportamento de cópula. Assim o presente trabalho apresentou como objetivo estudar o comportamento de cópula de Leucothyreus marginaticollis Blanchard, 1843. Os estudos foram conduzidos na fazenda experimental da Universidade Estadual de Mato Grosso do Sul em Aquidauana, MS, sendo realizadas coletas de adultos com armadilha luminosa de outubro a novembro de 2013. Com as coletas foram analisados os horários de voo em campo, e em laboratório machos e fêmeas foram separados, posteriormente foram formados casais e as etapas que envolvem o comportamento de cópula, verificadas. Vários adultos realizaram cópula, a qual durou em média 22,71 minutos e ocorreram das 19 às 23 horas. Após a cópula o macho se soltava da fêmea ou permanecia sobre essa, provavelmente para impedir que outro macho realizasse a cópula. Algumas fêmeas não aceitaram os machos para cópula, indicando que a formação de casais ocorre após o reconhecimento químico entre os adultos. O horário de maior coleta dos adultos em campo foi das 20 às 22 horas. Adultos podem se nutrir de folhas e flores de acerola (Malpighia emarginata DC, Malpighiaceae), folhas de aroeira (Myracrodruon urundeuva Allemão, Anacardiacea), frutos de uva (Vitis vinifera L., Vitaceae), maçã (Malus domestica Borkh., Rosaceae) e banana (Musa sp. L., Musaceae), ampliando-se as informações sobre o hábito alimentar dos adultos. Foram elucidadas as etapas relacionadas ao comportamento de cópula de L. marginaticollis, a qual pode auxiliar nos processos de extração e identificação de feromônio sexual.
ABSTRACT
AbstractThe genus Leucothyreus has been linked to some commercial plant crop pests. Eventhough several species have been described for this genus, information about this group is still scarce. This study investigated some biological aspects and mating behavior in Leucothyreus albopilosus. Studies were conducted at the State University of Mato Grosso do Sul, in the municipalities of Aquidauana and Cassilândia, MS, Brazil. For biological studies, adults were collected with light traps from February 2011 to February 2012, and for behavior analyses from September to December 2014. Biological studies were undertaken every three days and included the eggs inspection, and the separation of the newly hatched larvae to observe and describe their developmental stages; to monitor larval growth and differentiate larval instars, we measured the larvae cephalic capsule. Life cycle was determined starting from the newly laid eggs until adult death. For mating behavior studies, adults obtained with light traps were taken to the laboratory. As soon as they started flying in the evening, couples were formed and copulation steps were recorded. in the field, we observed that adults were mostly collected during warmer and wetter periods (from August to March). Our results showed that the embryonic period of L. albopilosus lasted 20.5 days, the 1st, 2nd and 3rd instars lasted 31.0, 33.1 and 85.6 days, respectively. The pupal stage lasted 20 days, and the egg to adult period was completed in 185.5 days; these results suggest that L.albopilosus can be characterized as a univoltine species. Observations of mating behavior in the laboratory showed that, after the sunset, adults projected a small portion of clypeus near the soil surface and flew off seeking a female to mate. The female could accept or reject the male for mating. When the female accepted the male, copulation occurred from 19:00 to 23:00 hours, and lasted 19.45 minutes on average. Sometimes females refused to mate, probably because the male or female were not sexually mature to perform copulation, and there might be a chemical communication between the adults. Adults were observed feeding on ripe bananas (Musa sp., Musaceae) and on mangaba flowers (Hancornia speciosa, Apocynaceae) in the laboratory. With this work we contributed with the description of mating behavior in the genus Leucothyreus and concluded that the biological cycle was completed in less than 200 days. Rev. Biol. Trop. 64 (2): 547-557. Epub 2016 June 01.
ResumenEn el género Leucothyreus se describen varias especies, sin embargo, hay poca información sobre este grupo. El presente trabajo tuvo por objetivo estudiar los aspectos biológicos y el comportamiento de copula de Leucothyreus albopilosus. Los estudios se realizaron en la Universidade Estadual de Mato Grosso do Sul, en los municipios de Aquidauana y Cassilândia, MS, Brasil. Fueron recolectados adultos con trampa de luz desde febrero 2011 hasta febrero 2012 para realizar estudios biológicos y desde septiembre hasta diciembre de 2014 para estudios de comportamiento. Para los estudios biológicos, se inspeccionaron los huevos cada tres días, y cuando las larvas eclosionaban, eran separadas para monitorear su desarrollo. Para supervisar el desarrollo y diferenciar las etapas larvarias fueron medidas las cápsulas cefálicas de las mismas. El ciclo de vida se determinó a partir de la ovoposición hasta la muerte de los adultos. Para realizar los estudios del comportamiento de la cópula, los adultos obtenidos con trampas de luz fueron llevados al laboratorio, y al atardecer cuando iniciaron el vuelo, se formaron parejas, permitiendo observar y registrar los pasos que involucran este comportamiento. En campo, se observó que los adultos fueron recolectados principalmente en los períodos más calientes y húmedos entre los meses de agosto y marzo. El período embrionario de L. albopilosus duró 20.5 días. La primera, segunda y tercera etapa duraron 31.0, 33.1 y 85.6 días, respectivamente. La etapa de pupa duró 20 días y el período desde huevo hasta adulto fue completado en 185.5 días. Estos resultados sugieren que L. albopilosus puede ser caracterizado como una especie univoltina. Con respecto al comportamiento de copula en el laboratorio, al iniciar la noche, los adultos primeramente proyectan una pequeña porción del clípeo próximo a la superficie del suelo, en seguida realizan el vuelo buscando una hembra para iniciar la cópula. La hembra puede aceptar o no al macho para realizar la cópula. Cuando la hembra aceptó al macho para la copula, esta ocurrió desde 19:00 hasta las 23:00 horas durando 19.45 minutos en promedio. Cuando la hembra rechazó al macho para la copula, se debió probablemente a que ella o el no estaban maduros sexualmente, ocurriendo un reconocimiento químico entre ellos. Se observó en el laboratorio que los adultos se alimentaban de plátanos maduros (Musa sp., Musaceae) y flores de mangabeira (Hancornia speciosa, Apocynaceae). En este trabajo se concluye que el ciclo biológico se completa en menos de un año y se describen las primeras etapas del comportamiento de copula del género Leucothyreus.
Subject(s)
Animals , Male , Female , Sexual Behavior, Animal/physiology , Coleoptera/physiology , Oviposition/physiology , Seasons , Coleoptera/classificationABSTRACT
Biological aspects of Leucothyreus ambrosius Blanchard (Coleoptera, Melolonthidae, Rutelinae). Coleopterans of the family Melolonthidae comprise a large group of species that feed on different food sources, including plant roots, stems, and leaves, in addition to plant materials at different decomposition stages. Several species are found in the genus Leucothyreus, occurring in different regions of Brazil, including the various biomes in the country. Information on the biology of species of the genus Leucothyreus is scarce, therefore, we conducted studies on the biological aspects of Leucothyreus ambrosius Blanchard, 1850. The period of adult occurrence was determined with a light trap installed between a cropped and pasture area in the municipality of Aquidauana, Mato Grosso do Sul State, Brazil. Adults collected in the field were used to form insect pairs and the studies were initiated in the entomology laboratory as the adults began ovipositing. Adults were observed flying in the field from October to December. Eggs were obtained as pairs were formed and a colony was established, the embryonic period lasting 14.6 days on average. The larval period in the 1st instar lasted 21.6 days, in the 2nd instar 19.6 days, and in the 3rd instar, 85.6 days. The head capsule width was 1.48 mm in the 1st instar, 2.44 mm in the 2nd, and 3.83 mm in 3rd larval instar. The pupal stage had an average duration of 35.5 days. The egg to adult period lasted 173.3 days. Morphometric information for the larval and adult stages is presented in this study.
ABSTRACT
Biological aspects of Leucothyreus alvarengai Frey and Leucothyreus aff. semipruinosus Ohaus (Coleoptera, Melolonthidae, Rutelinae) in crop succession at central Brazil. Beetles of the family Melolonthidae make up a large group and some species are considered pests of planted crops. Little information is available on the basic biological aspects of the genus Leucothyreus, such as association with cultivated crops and their occurrence periods. Therefore studies were developed in soybean and corn crops in Tangará da Serra, Mato Grosso, Brazil, with the objective of studying the occurrence and biological aspects of Leucothyreus alvarengai Frey and Leucothyreus aff. semipruinosus Ohaus. For acquisition of immature specimens of both species, in April 2011 sampling was performed in corn fields, in July and October in the fallow area, and in soybeans fields planted in December; in 2012 sampling was performed in January and February in soybean fields and in March in corn fields. In 2011 the total number of larvae obtained in April, July, October and December were 100, 6, 30 and 27, and in January, February and March of 2012 these quantities were 32, 52 and 65 larvae, respectively. In all sampling events the larvae of L. alvarengai were collected in greater quantity. At the beginning of the reproductive period of L. alvarengai and L. aff. semipruinosus, it was observed that the adults began to fly and soon after started oviposition in the field in September. The appearance of larvae coincides with the time of soybean planting in the field, thus the larvae feed on roots of soybean plants at the beginning of their development and the cycle from egg to adult of the two species was completed in one year.
ABSTRACT
Herbivore attack by Bolax palliata Burmeister is reported on two sympatric bracken species: Pteridium caudatum (L.) Maxon and P. arachnoideum (Kaulf.). Laboratory and field observations revealed a preference for the last of the two species. Available phytochemical information suggests it could be based on differences in concentration of condensed tannins.
Se reporta la herbivoría de Bolax palliata Burmeister sobre dos especies simpátricas del helecho macho: Pteridium caudatum (L.) Maxon and P. arachnoideum (Kaulf.). Observaciones de laboratorio y campo mostraron preferencia por la última de estas especies. La información fitoquímica disponible sugiere que esta selección podría estar basada en diferencias en la concentración de taninos condensados.