Load Capacity of Workers of Atta robusta During Foraging (Hymenoptera: Formicidae)

Worker ants are highly polymorphic in the genus Atta and they are usually classified into castes according to the specific functions they perform in a colony. Minor workers (head width ≤ 2.0 mm) help to maintain and grow the symbiotic fungus whereas larger workers (head width > 2.0 mm) cut and transport plant fragments. This study investigated the roles in the cutting and transporting of different plant resources of different Atta robusta worker classes that were classified based on the size of their head capsule. Experiments were conducted in the restinga of Grussaí/Iquipari, São João da Barra, Rio de Janeiro State, Brazil. In each month between October 2009 and September 2010, we collected 100 ants and their respective loads from the trails of four nests of Atta robusta. The samples were individually transported to the laboratory, where the ants and their loads were weighed and the head capsules of the ants were measured. Large ants transported heavier loads. These ants usually transported more fruit and seeds than smaller ants

Termite (Isoptera) survey in urban area in Northern of Rio de Janeiro State, Brazil.

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

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.

Levantamiento de termitas (Isoptera) en área urbana del norte de Río de Janeiro, Brasil

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.La mayoría de las termitas plagas de área urbana en Brasil son especies exóticas, pero algunas especies nativas también están comenzando a representar un problema creciente. Este estudio tuvo como objetivo identificar las especies de termitas que infestan árboles y casas en la ciudad de Campos dos Goytacazes, en el norte del estado de Río de Janeiro. Los árboles de calles de dieciséis vecindarios fueron inspeccionados y los ataques por termitas fueron registrados. También se realizaron entrevistas con propietarios de residencias de los mismos vecindarios y sus domicilios fueron inspeccionados para verificar la ocurrencia de ataque de termitas. Las termitas fueron registradas en 17 % de los 1.307 árboles inspeccionados. La especie más frecuente fue Coptotermes gestroi (51 % de los árboles infestados), Nasutitermes corniger y Microcerotermes strunckii fueron especies de ocurrencia intermedia (38 % y 14 %, respectivamente) y Microcerotermes arboreus (1 %) fue la menos común. Las infestaciones de árboles por más de una especie ocurrieron en 14 % de los casos (n = 31). Las infestaciones de termitas también se presentaron en 26 % de las residencias inspeccionadas (n = 1.020). Las cuatro especies que causaron daños en domicilios fueron Cryptotermes brevis, C. gestroi, N. corniger y M. strunckii. La especie más común, encontrada en 133 residencias, fue C. brevis (51 %). C. gestroi y N. corniger pueden ser consideradas especies secundarias en términos de la presencia en las residencias pero fueron responsables por más daños estructurales que C. brevis que atacó principalmente el mobiliario

Caste polymorphism of apterous line of the Neotropical termite Nasutitermes corniger (Motschulsky) (Isoptera, Termitidae)

Termite societies are structured by individuals that can be grouped into castes and instars. The development of these instars in most species occurs in irregular patterns and sometimes is distinguished subcastes in physical systems that originate polymorphic soldiers and workers. In this study, we characterized the morphological diversity of castes of apterous in Nasutitermes corniger. We collected four colonies of N. corniger, one every three months between May 2011 and February 2012. Individuals of the nest were separated into groups: larval stages, workers and presoldiers and soldiers. A morphometric analysis was performed on individuals from each group based on head width, metatibia, antenna, and thorax length. The data were submitted to discriminant analysis to confirm different morphological types inside these groups. The apterous line of N. corniger is composed of one first larval instar and two second larval instar. The workers caste has two lines of development with four instars in a larger line and three instars in a lower line. Two morphological types were identified in presoldiers and soldiers. The pattern of castes was similar to other species of the genus, in which bifurcation into two lines of workers, one smaller and one larger occurs after the first molt