No abstract

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.

No abstract

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.

No abstract

In social insects, collective behavior is regulated by substances secreted by various glands of different members of society. In this study, we investigate whether salivary glands of the arboreal termite Nasutitermes corniger (Motschulsky) (Isoptera: Termitidae) contain substances that regulate the intensity of foraging behavior. Foraging arenas of N. corniger nests maintained under laboratory conditions received the addition of two filter paper substrates, one impregnated with salivary gland extract from third-instar small workers (SW3) (treatment) and the other impregnated with distilled water (control). A similar experiment was conducted using salivary gland extract from fourth-instar large workers (LW4). Occurrences of initial exploration, mass recruitment, and substrate gnawing behaviors, as well as numbers of recruited and gnawing workers, were recorded. There was a higher rate of mass recruitment to treated substrates than to the control (SW3: 80 vs. 25%; LW4: 90 vs. 25%). Gnawing behavior also occurred at higher rates on treated substrates (SW3: 95 vs. 35%; LW4: 100 vs. 45%). The number of workers recruited to and gnawing on treated substrate was significantly higher than the number of workers recruited to and gnawing on control substrate. The higher rates of worker recruitment, as well as the higher numbers of recruited and gnawing workers, show that salivary glands of last-instar workers contain substances with arresting and/or phagostimulating pheromonal actions or substances that release compounds with these properties.

Most pest termites in urban areas in Brazil are exotic species, but native species are becoming an increasing problem. This study aimed to identify termite species infesting trees and houses in urban areas of Campos dos Goytacazes, in the north of Rio de Janeiro State. Trees in the streets of sixteen neighborhoods were inspected for termites. Inspections and interviews were also conducted to verify the occurrence of termites in houses. Termites were recorded in 17 % of the 1,307 trees surveyed. Coptotermes gestroi was the most frequent species (51% of infested trees), Nasutitermes corniger and Microcerotermes strunckii were present in 38 % and 14 % of infested trees, respectively, and Microcerotermes arboreus was the least common (1 %). Different termite species coexisted in 14 % of the infested trees (n = 31). Termite infestations were recorded in 26% of the surveyed households (n = 1,020). Four species were identified as causing damage: Cryptotermes brevis, C. gestroi, N. corniger, and M. strunckii. The most common species was C. brevis, affecting 133 residences (51 %). C. gestroi and N. corniger were less frequent, but they were responsible for more structural damage than C. brevis, which mainly attacked furniture.

The members of the family Phoridae (Insecta: Diptera), whose adults are commonly known as scuttle fly or humpbacked fly, differ widely as to their feeding habits in the larval and adult stages. Dipteran larvae of Megaselia Róndani, 1856 (Diptera: Phoridae) vary considerably in feeding habits. The results of this study confirm the parasitic and frugivorous habits of Megaselia larvae. Megaselia scalaris (Loew, 1866) behaved as primary parasitoid of Isognathus caricae (L., 1758) (Lepidoptera: Sphingidae) larvae in confinement using cage under laboratory conditions. It is also the first time the frugivorous habit of M. scalaris larvae is recorded in ripe fruits of the avocado tree (Persea americana, Lauraceae) under field conditions.