Decayed Wood Affecting the Attraction of the Pest Arboretum Termite Nasutitermes corniger (Isoptera: Termitidae) to Resource Foods

Nasutitermes corniger shows preferential feeding for the wood of different tree species, but it is not known whether attractiveness is a function of the state of decay. This study examined the foraging behavior of N. corniger towards wood in different stages of decay. Wood was exposed to weather for durations of 0, 3, 6 or 9 months. Then the wood was placed in a standard foraging arena with termites. Exploration and recruitment behavior were recorded for 1 h. Separate bioassays were conducted for three species: Pinus elliottii, Eucalyptus grandis and Manilkara huberi. In the tests with P. elliottii and E. grandis, more individuals were recruited to wood decayed for 6 months  (191 and 185, respectively) than to undecayed wood (12 and 69, respectively). Similarly, more individuals were recruited to decayed M. huberi wood than undecayed, but only after 9 months (249 and 7, respectively). Decayed wood has therefore been demonstrated to be more attractive to N. corniger than undecayed wood. The different decomposition rates necessary to increase attractiveness may be explained by differences in wood density.

The efficiency and working principle of conical physical barrier against the leaf-cutting ants

As formigas cortadeiras são importantes pragas agrícolas e florestais e podem ser controladas por diferentes métodos, entre os quais as barreiras físicas que impedem o acesso dessas formigas à planta. Objetivou-se avaliar a eficiência e o princípio de funcionamento de cones de lâmina de acetato em dois tamanhos de geratriz como barreiras físicas contra essas pragas. Dois experimentos foram conduzidos em quintal residencial em Petrópolis, RJ. Um dos experimento, usando pedaço de casca de laranja como isca atrativa para essas formigas, consistiu de três tratamentos: isca protegida com cone de 5,4 ou 10,8 cm de geratriz e isca sem cone (controle) (dez repetições/tratamento). No outro experimento, esses cones foram colocados em uma raiz de Araceae para conter intenso fluxo de formigas. Identificaram-se duas espécies de quenquéns: Acromyrmex niger (F. Smith) e Acromyrmex disciger (Mayr). Duas iscas foram cortadas pelas quenquéns quando protegidas pelo cone pequeno, nenhuma pelo cone grande e todas as iscas foram cortadas no controle. O fluxo das quenquéns na raiz foi contido pelo cone pequeno por apenas 10 minutos, enquanto que o cone grande o conteve durante as 3 horas de observação. A tendência das quenquéns em explorar preferencialmente a borda do cone pode explicar o seu funcionamento.Palavras-chave: Formicidae; Myrmicinae; Attini; barreira antiformiga; controle mecânico. AbstractThe efficiency and working principle of conical physical barrier against the leaf-cutting ants. The leaf-cutting ants are important agricultural and forest pests and may be controlled by different methods. Among them, the physical barriers that prevent the access of these ants to the plants. The present work aimed to evaluate the efficiency and the working principle of cones of acetate foil at two generatrix sizes as physical barriers against these pests. We conducted two experiments in home garden in the municipality of Petropolis, RJ. An experiment used slice of orange peel as attractant bait for leaf-cutting ants and three treatments: bait protected with cone of 5.4 or 10.8 cm of generatrix, and bait without cone (control) (ten replicates/treatment). In another experiment, we placed these cones on a root of Araceae in order to control the intense flow of ants. It was identified two species of leaf-cutting ants: Acromyrmex niger (F. Smith) and Acromyrmex disciger (Mayr). The leaf-cutting cut two baits protected by the small cone, none of the baits protected by the big cone, and cut all the baits in control. The flow of the leaf-cutting ants on the root was controlled by the small cone during only 10 minutes, while the big cone controlled the flow during the 3 hours of observation. The tendency of the leaf-cutting ants to explore preferentially the edge of the cone may explain its operation.Keywords: Formicidae; Myrmicinae; Attini; anti-ant barrier; mechanical control.AbstractThe leaf-cutting ants are important agricultural and forest pests and may be controlled by different methods. Among them, the physical barriers that prevent the access of these ants to the plants. The present work aimed to evaluate the efficiency and the working principle of cones of acetate foil at two generatrix sizes as physical barriers against these pests. We conducted two experiments in home garden in the municipality of Petropolis, RJ. An experiment used slice of orange peel as attractant bait for leaf-cutting ants and three treatments: bait protected with cone of 5.4 or 10.8 cm of generatrix, and bait without cone (control) (ten replicates/treatment). In another experiment, we placed these cones on a root of Araceae in order to control the intense flow of ants. It was identified two species of leaf-cutting ants: Acromyrmex niger (F. Smith) and Acromyrmex disciger (Mayr). The leaf-cutting cut two baits protected by the small cone, none of the baits protected by the big cone, and cut all the baits in control. The flow of the leaf-cutting ants on the root was controlled by the small cone during only 10 minutes, while the big cone controlled the flow during the 3 hours of observation. The tendency of the leaf-cutting ants to explore preferentially the edge of the cone may explain its operation.Keywords: Formicidae; Myrmicinae; Attini; anti-ant barrier; mechanical control

Influence of Food Resource Size on the Foraging Behavior of Nasutitermes corniger (Motschulsky)

In general, termite foraging can be affected by physical and chemical factors linked to food. This study investigated if the wood length of Eucalyptus grandis W. Hill ex Maiden, as a food resource, influences the behavior of foraging events of Nasutitermes corniger (Motschulsky). Nests with mature and active colonies were collected in the field and transferred to glass cubes connected to a test arena under laboratory conditions. Wooden blocks of E. grandis, with a 2.5 x 2.0 cm rectangular cross section, were offered to termites in three different lengths: 5, 10 and 15 cm. Each test was repeated with 20 nests and lasted 60 minutes, when the following behavioral events and their duration were observed: initial exploration, initial recruitment and mass recruitment. At the end of each test, the quantities of termites (total, workers and soldiers) and gnawing workers were determined. The results show that longer blocks favored a higher occurrence of exploration and initial recruitment. However, the highest mass recruitment occurred with the 10 cm blocks. The length of the wood influenced the total number of termites recruited and gnawing workers; both were highest for the 10 cm blocks. There was no significant difference in relation to exploration time of the blocks and number of workers and soldiers recruited. Therefore, we conclude that wood length is a factor that can affect N. corniger foraging

Does the distance between the nest and the food source affect the foraging behavior of Nasutitermes corniger (Termitidae)?

Research on food finding by pest termites can be used to inform the development of techniques to control their population; however, there is a paucity of information available on the foraging behavior of Nasutitermes corniger, an urban pest in South America. In the present study, we analyzed the effect of the distance between the nest and food on the exploration and recruitment of N. corniger during foraging behavior under laboratory conditions. Nests containing mature colonies were collected in the field and placed in a glass cube connected to a test arena (50.0 × 40.0 cm) in which Eucalyptus grandis blocks were supplied at three different distances: 10, 20 and 30 cm. In each test, the occurrence of the following events were recorded: initial exploitation, initial recruitment, and mass worker recruitment. Individuals in the blocks were counted at the end of each test and divided into the total number of recruited termites, recruited workers, consuming workers and recruited soldiers. Each test lasted 60 minutes and was repeated with 20 colonies. Nasutitermes corniger foragers showed the three behavioral events of interest at all three distances. The occurrences of initial exploitation and initial recruitment, the latency of the three events and the number of foragers were not affected by the distance between the nest and food. The occurrence of mass worker recruitment was the only event affected by this distance, with higher recruitment at shorter distances

A new report on Hesperomyces coleomegillae (Ascomycota, Laboulbeniales) parasitism of Coleomegilla maculata (Coleoptera, Coccinellidae) in Brazil

For the first time, the genus Hesperomyces has been reported to infect Coleomegilla maculata in laboratory mass rearing in Brazil. Thalli were found growing on several parts of this ladybird species, including the head, elytra, legs, and abdomen. Infested adults died after 60 days

Influence of the amount of food resources in the foraging behavior of Nasutitermes corniger (Motschulsky)

Food scarcity or abundance are factors regulating termites’ foraging behavior in general. The aim of the present study is to evaluate the influence of four amounts of Eucalyptus grandis on foraging behavior events shown by worker and soldier of Nasutitermes corniger during laboratory tests. The tests were carried out with adult and active N. corniger colonies found in nests collected in the field, which were stored in glass cubes connected to the test arenas. Four different amounts of wood blocks were used in the tests and each amount concerned a treatment and defined a different experimental group: 1, 2, 3 and 4 blocks/arenas, with 5 repetitions. Each test lasted 60 minutes and consisted in observing, or not, the occurrence of behavioral events shown by foragers when they had contact with the treatment. The duration of each event was recorded, whenever it was observed. The number of recruited foragers and the number of workers consuming the blocks were recorded at the end of each test applied to each treatment. Nasutitermes corniger presented the three behavioral events in all treatments; however, there was not significant difference between treatments in the occurrence of the two first events, in the time taken from test start to the occurrence of a new event, in the number of recruited termites and in the number of gnawing workers. Only workers’ mass recruiting was influenced by the amount of wood available. The occurrence of this event was significantly higher in treatments with greater amounts of wood. Thus, N. corniger adjusts its mass recruitment behavior in response to available food amount, which should be considered when developing baiting system for its control

Comunidade de joaninhas (Coleoptera: Coccinellidae) em consórcio de couve (Brassica oleraceae var. acephala) com coentro (Coriandrum sativum) sob manejo orgânico.

As abordagens agroecológicas de produção orgânica vegetal visam a diversificação dos cultivos, estimulando a persistência, a abundância e a diversidade de inimigos naturais que atuam no controle biológico de insetos-pragas. Nesse contexto, o presente estudo teve por objetivos determinar a diversidade e a estrutura da comunidade de joaninhas predadoras (Coleoptera: Coccinellidae) associados a pulgões em couve, cultivada em consórcio com coentro. O estudo foi realizado na unidade experimental de produção integrada lavoura-pecuária denominada de Sistema Integrado de Produção Agroecológica, SIPA, em Seropédica, RJ. Os tratamentos foram consórcio de couve com coentro e o monocultivo de couve. A diversidade de joaninhas foi determinada por meio da coleta de indivíduos através de amostragens por remoção. Um total de 25 espécies de joaninhas está presente no SIPA. Não houve infestação por pulgões na couve consorciada com coentro, o qual foi usado pelas joaninhas como sítio de alimentação, oviposição, abrigo para larvas, pupas e adultos, além de acasalamento

Interceptação de Sinoxylon unidentatum (Coleoptera: Bostrichidae) no Rio de Janeiro, Brasil

A ocorrência da praga quarentenária (A2), Sinoxylon unidentatum Fabricius (Coleoptera: Bostrichidae) foi confirmada e interceptada no Porto do Rio de Janeiro, em paletes oriundos da Indonésia. Constatou-se que o brometo de metila não foi suficiente para inibir a ação dos insetos nos paletes. Sugere-se, como medida de monitoramento, a instalação de armadilhas etanólicas nos locais de armazenamento e trânsito de madeiras ou material lenhoso

Natural host plants and native parasitoids associated with Anastrepha pulchra and other Anastrepha species (Diptera: Tephritidae) in Central Amazon, Brazil

A natural host (Mouriri collocarpa) and a parasitoid (Doryctobracon areolatus) for Anastrepha pulchra are reported for the first time in Brazil. We report new hosts for Anastrepha atrigona and Anastrepha bahiensis in the Brazilian Amazon. Parasititoids attacking A. atrigona, Anastrepha coronilli, and A. pulchra are reported

Faunistic analysis and seasonal fluctuation of ladybeetles in an agro-ecological system installed for organic vegetable production

Plans for an agro-ecological system for agricultural production must consider vegetal diversification in agricultural properties because, among other advantages, it can help the biological control of pests when it focuses on such an end. Predator ladybeetles (Coleoptera: Coccinellidae) can be found in different environments; they play an important role in biological control. The aims of the present study were to feature ladybeetle populations through faunistic analysis and determine their fluctuations in an agro-ecological system comprising seven sub-systems subjected to different cultivation systems in Seropédica County, RJ. The experiment was conducted from December/2018 to December/2019 at Módulo de Cultivo Orgânico Intensivo de Hortaliças (MCOIH), which is located at Sistema Integrado de Produção Agroecológica (SIPA). In total, 1,231 adult ladybeetles were captured, distributed into 13 species, 3 genera and 2 tribes of Coccinellidae, which resulted in S (taxon richness) = 19, Shannon-Wiener diversity index (H’) = 0.65 (at 0 to 1 scale) and Margalef diversity index (α) = 2.53 (values lower than 2.0 represent low diversity sites). Equitability was low (E = 0.22), since one of the ladybeetle species has prevailed: Cycloneda sanguinea (most frequent, dominating and constant) in MCOIH, as well as in each of the sub-systems. However, the simplest sub-systems installed for vegetable production (monoculture gardens) were not favorable for ladybeetle diversity, whereas sub-systems installed for polyculture of leafy vegetables recorded the greatest taxa diversity of ladybeetles, including species that predate in aphids that attack vegetables [Coleomegilla maculata, Coleomegilla quadrifasciata, Cycloneda sanguinea, Eriopis connexa, Harmonia axyridis, Hippodamia convergens and Hyperaspis (Hyperaspis) festiva]. The sub-system comprising gliricidia was used to produce fertilization biomass and favored the predominance of C. sanguinea in comparison to the other ladybeetle species in MCOIH. Spring was the season mostly favoring the occurrence of C. sanguinea and H. convergens adults; which were dominant species in ladybeetle assemblage in MCOIH; however, C. sanguinea was constant and H. convergens was accessory