Sobre a biologia do Ornithocoris toledoi Pinto, 1927

Percevejo dos galinheiros em Minas Gerais (Hemíptera, Cimicidae)

Resumo

This paper reports results of investigations and studies on the life history of the chicken bedbug, Ornithocoris to- ledoi Pinto, 1927 (Hemiptera, Cimicidae, Cimicinae). This insect, described by Cesar Pinto from specimens taken at LIMEIRA, São Paulo, Brasil, in 1927, is a common parasite of chickens in the state of Minas Gerais. At present the genus Ornithocoris includes only two species: O. teledoi, parasite of Gallus domesticus, and O. furnarii (Cordero et Vogelsang, 1928), found in the nests of Furnarius rufus in Uruguay. Ornithocoris toledoi inhabits poultry . houses, hiding behind nest boxes, under boards and in cracks in the walls and roof during the day. Under field conditions the insect is negatively phototropic and comes.out of hiding to suck the blood of the host only at night. The studies reported in this article were made under laboratory conditions, supplemented by field observations. In the laboratory feeding occurred at almost any hour of the day or night. Adult bugs visited the host at 8 day intervals, remaining in the feeding position from 8 to 12 minutes. Nymphs fed from 6 to 9 minutes. In- gested blood is digested in 3 to 4 days after leaving the host. Some adults lived 8 months in the absence of food while others died at 5 months. Under experimental condi- tions the bugs attacked turkeys, pigeons and ducks, but did not feed on man. As observed in these studies, the females mated only once. Copulation occurred soon after the adult female's first meal. Egg-laying is begun from 5 to 8 days alter mating. The eggs, which measure 369 microns by 697 microns are either placed in groups of 2 to 4 or laid in undivided mas- ses. An average of 4 separate egg-laying periods was ob- served. These were spaced at 6 to 10 day intervals with a range of 8 to 14 eggs per period. At room temperature the incubation period varies from 5 to 10 days with an average of 7 or 8 days. In all cases feeding was necessary before a new egg-laying period was begun. In cases where the female was not permitted to visit the host, no further repro- duction was observed. The female lives a little longer than 4 months after the last egg-laying period. The nymph passes through 5 instars with an average of 5 to 8 days per instar and feeds from 1 to 3 times be- tween molts. An average of 8 to 10 meals were taken du- ring the nymphal stage. The average life cycle under labo- ratory conditions was completed in 43 days; the shortest observed was 36 days. Ornithocoris toledoi is a serious pest of chickens in Minas Gerais. The presence of this parasite in poultry hou- ses is accompanied by large decreases in egg production and apparently by increased susceptibility of the flock to diseases. At present the possible role of this insect as a disease vector is being investigated and experiments in prac- tical control methods are in progress.