Biologia e caracterização morfológica de Ornithocoris pallidus (Usinger, 1959) (Heteroptera: Cimicidae: Haematosiphoninae)

Abstract

The cimicidae are distributed in six subfamilies. Among theses Haematosiphoninae has nine genera and Ornithocoris two species: Ornithocoris toledoi Pinto, 1927, for be commonly associated with chickens show economic importance and Ornithocoris pallidus (Usinger, 1959), silvatic associated mainly with swallows. Knowledgment about biology and morphology of this species will contribute to the characterization of taxonomic genus, whose studies are concerning to adult and 5th instar nymphs. Eggs, nymphs and adults were obtained from 10 nests collected in Paula Cândido municipality (MG), and maintained in laboratory conditions feeding on Mus musculus mice. The study was conducted from established colonies with adults coming from the field. Biological parameters were avaiable (life cycle, number of meal, resistance to starvation and longevity of adults) and morphological of egg and nymphs were observed by optical microscopy (OM) and scanning electron microscopy (SEM). From a total of 2005 eggs, 187 were assigned to the life cycle, 34 and 30 for resistance to starvation and longevity, respectively, and 120 for morphology. Of the 187 nymphs of 1st instar for individualized cycle and number of meal observed, 142 completed the 1st, 88 the 2nd, 80 the 3rd and 76 the 4th instar. The morphometric and chromatic study were performed with 30 eggs (length and width) and 30 nymphs of each instar (total body length and head width of the head with eyes, interocular distance, pronotum height, length pronotal bristle, length of antennal segments of the rostrum and 3rd pair of legs, length and femur width). To the OM study, insects were diaphanized in KOH 10% heated, washed with distilled water, then immersed in acetic acid 1% and mounted between slide and cover slip in alcohol 15%, to observed using optical microscope coupled with a camera lucida. For SEM, the insects were mounted on metal brackets attached with double-sided tape, kept in an oven at 50°C for 24 hours and covered with gold for viewing by scanning electron microscope JEOL JSM 6390 LV - Electron Microscopy Platform Rudolf Barth - FIOCRUZ. The life cycle from egg to adult presented four nymphal instars, at a mean time of 52 ± 10.7 days, performing 0-8 meals, depending on the instar. Males were less resistant to fasting and with less longevity than females, with a mean of 60 ± 19.8 and 66 ± 21.2 and 225 ± 104 and 301 ± 106 days, respectively. The nymphs of 1st and 2nd instars needs more meals and presentes natural mortality, respectively, than the other stages. Among 4th instar, some measured parameters had similar mean to those obtained by Usinger (1966), and eggs of O. pallidus larger than O. toledoi (Carvalho, 1939). As for color, the egg varies from translucent to dark brown; N1 to N3 are light brown and N4 dark brown. By MO, N1 differs from others by having 1 + 1 long bristle at the humeral angle of pronotum, while N2 to N4 have two bristles. SEM, N1 to N4 have a structure at the apex of the 2nd antennal segment, not yet described in the literature, and a ctenidium at the apex of the tibia of the 1st pair of legs also observed by Usinger (1966) in Paracimex capitatus nymphs, Morphological aspects such as the antennas structures that needs further studies, the bristles of pronotum and the presence of ctenidium will provide subsidies to increase the dichotomous key developed by Usinger (1966). The definition of four nymphal instars to O. pallidus corroborate those obtained by Jansen (1979) to O. toledoi, and state that genus Ornithocoris may be characterizate with four nymphal instars.