Ultrastructure of the Bacteriocytes in the Midgut of the Carpenter ant Camponotus rufipes: Endosymbiont Control by Autophagy

The carpenter ant Camponotus rufipes has intracellular bacteria in bacteriocytes scattered in the midgut epithelium, which have different amounts of endosymbionts, according to the developmental stages. However, there are no detailed data about the midgut cells in adult workers. The present work aimed to evaluate the morphology and cellular events that coordinate the abundance of endosymbionts in the midgut cells in C. rufipes workers. The midgut epithelium has digestive cells, bacteriocytes, and cells with intermediate morphology. The latter is similar to bacteriocytes, due to the abundance of endosymbionts, and similar to digestive cells, due to their microvilli. The digestive and intermediate cells are rich in autophagosomes and autolysosomes, both with bacteria debris in the lumen. These findings suggest that midgut cells of C. rufipes control the endosymbiont level by the autophagy pathway.

Evidence of Competition Between Two Canopy Ant Species: Is Aggressive Behavior Innate or Shaped by a Competitive Environment?

Competition occurs in all ecological communities, although it has not always been experimentally tested as a structuring force in the distribution of species. We tested the hypothesis that the aggressiveness exhibited byCamponotus rufipeschanges according to the pressures of a competitive environment. This is a dominant species in the montane forest of the Itacolomi State Park, Brazil, whereCamponotus sericeiventrisdoes not occur. Using bait traps in a field site where both species occur, (“Juiz de Fora” site) we showed thatC. sericeiventriswas able to removeC. rufipesworkers at the same bait. In the laboratory, we used dyadic encounters to test workers from both species taken from colonies found in areas where both occur and where onlyC. rufipeswas found.Camponotus rufipesfrom Itacolomi fought significantly less and was killed during the first few minutes in 60% of the events. On the other hand, the workers that co-existed withC. sericeiventrisin the field were more aggressive, but less efficient fighters than the latter. This investigation demonstrated existence of competition betweenC. rufipesandC. sericeiventris, and also the lower aggressiveness ofC. rufipes'individuals that did not co-exist in the field withC. sericeiventris.

Trail-Laying Behaviour as a Function of Resource Quality in the AntCamponotus rufipes

Chemical trails have been shown to act as an orientation cue in some ant species. Here, I report that the trail-laying behaviour in the nectar-feeding ant,Camponotus rufipes, varies with the concentration of the sucrose solutions collected. Single workers collected solutions of different sucrose concentrations (5%, 20%, and 40% in weight) during 4 consecutive visits to the resource, and their trail-marking behaviour was recorded on soot-coated slides during their first and last visits. Results suggest that these chemical trails provide both an orientation cue between the nest and the food source, as previously suggested forCamponotusants, as well as information about food quality.

Dinâmica Populacional de Pulgão Preto dos Citros (Sternorrhyncha) em Cultivo Orgânico de Tangerina (Citrus reticulata Blanco) em Seropédica-RJ

O pulgão Toxoptera citricida (Kyrkaldy) (Sternorrhyncha) é um potencial transmissor do vírus da tristeza cítrica sendo considerada uma praga importante para a cultura, foi realizado monitoramento quinzenais no período entre outubro de 2002 a outrubro de 2003, com o objetivo de estudar a dinâmica populacional deste afídeo, incluindo predadores e a interação com formigas, em cultivo orgânico de tangerina cv. Poncã, Fazendinha Agroecológica, Seropédica, RJ. A Análise faunística dos formicídeos atendentes e dos predadores, foi através dos índices de diversidade de Shanon-Wiener (H') e Simpson (D), dominância de Berger-Parker (d) e equitabilidade J (e). Os predadores considerados efetivos na redução populacional do Pulgão preto dos citros (PPC) foram Cycloneda sanguinea (L.), Azya luteipes Mulsant e Pseudodorus clavatus (Fabr.), apesar de terem sido registrados oito predadores atacando colônias do PPC. Verificou-se C. sanguinea com maior pico populacional, seguido de P. clavatus e A luteipes. A diversidade e equitabilidade dos predadores foi considerada alta (H'= 0,7979; D =0,9638; e= 0,8836). Atendendo o PPC registrou-se Brachymyrmex sp., Camponotus rufipes (Fabricius) Camponotus atriceps (Fabricius), Camponotus crassus (Mayr), Camponotus clypeatus (Mayr); Crematogaster sp., Solenospis sp., Ectatomma brunneum (Fabricius) e Pseudomyrmex termitarius (Fr. Smith). A diversidade de formicídeos foi considerada mediana pelo valor H' (0,6585) e alta pelo valor D (0,9012). A equitabilidade também foi considerada mediana (e =0,69). A dinâmica populacional de T. citricida é influenciada pela brotação foliar seguido da predação e o atendimento de formigas. Estes dois últimos fatores são antagônicos devido a proteção oferecida pelas formigas ao PPC. Populational Dynamic of Brown Citrus Aphid (Sternorrhyncha) in Organic Cropping of Tangerine (Citrus reticulata Blanco) in Seropédica – RJ Abstract. The aphid Toxoptera citricida (Kyrkaldy) (Sternorrhyncha) is a potential vector of citrus virus tristeza, consider an important pest of the orchard. Was realized bimonthly monitoring between October 2002 and October 2003, with aim of study the populational dynamic this aphid, included predators ant ant-tending, in organic cropping of tangerine cv Ponkan, Fazendinha Agroecológica, Seropédica, RJ. The faunistic analysis of the ant-tending and predators, were realized across Shanon-Wiener (H') and Simpson (D) diversity index's, Berger-Parker dominance (d) and equitability J (e). The predators considered efficient in the populational reduction of brown citrus aphid (BCA), was Cycloneda sanguinea (L.), Azya luteipes Mulsant and Pseudodorus clavatus (Fabr.), although has been registered eight predators attacking BCA colonies. Verified that C. sangiunea obtained the biggest populational peak, following P. clavatus and A. luteipes. The predators diversity and equitability was considered high (H'= 0.7979; D =0.9638; e= 0.8836). Tending BCA, was registered Brachymyrmex sp., Camponotus rufipes (Fabricius) Camponotus atriceps (Fabricius), Camponotus crassus (Mayr), Camponotus clypeatus (Mayr); Crematogaster sp., Solenospis sp., Ectatomma brunneum (Fabricius) and Pseudomyrmex termitarius (Fr. Smith). Ant-tending was considered medium to H' value (0.6585) and high to D value (0.9012). The equitability was considered medium too (e =0.69). T. citricida populational dynamic is influenced to foliar shoot following predation and ant-tending. These two end factors are antagonist due to protection offer to ants at BCA.

Detecção de Aethalion reticulatum (L., 1767) (Hemiptera: Aethalionidae) em alfavaca-cravo (Ocimum gratissimum L.) e observações sobre sua ocorrência

O objetivo deste trabalho foi relatar a ocorrência da cigarrinha Aethalionidae em alfavaca-cravo (Ocimum gratissimum L.) no município de Bandeirantes-PR. Plantas com cerca de dois anos, na fase reprodutiva, com inflorescências, flores, frutos e sementes, serviram como fonte para a coleta de ninfas e adultos das cigarrinhas. Registrou-se em alfavaca-cravo a espécie Aethalion reticulatum e a interação com as formigas Camponotus rufipes e C. crassus.