Thiago de Carvalho Moretti

O papel de insetos (Blattodea, Diptera e Hymenoptera) como possíveis vetores mecânicos de helmintos em ambiente domiciliar e peridomiciliar

Helminths can be transmitted to human beings in several ways, but little attention has been given to vector or mechanical transmission of infective forms by insects. The present study surveys the helminth species present in three orders of insects that coexist in proximity with the human environment. A total of 700 insects (54 Blattodea, 275 Diptera, and 371 Hymenoptera) were collected and examined externally and individually. In the Blattodea order, only specimens of Periplaneta americana were collected, and 58.3% were carrying the following helminth forms: Oxyuridae eggs (36.4%), Ascaridae eggs (28.04%), Nematoda larvae (4.8%), Cestoda eggs (3.5%), other Nematoda (0.08%), and Toxocaridae eggs (0.08%). No Diptera and Hymenoptera were found to contain parasitic forms. This study evaluates the importance and role of insects as mechanical vectors of helminth parasites, correlated with social and environmental conditions, and suggests the use of these data for preventive purposes.

Cephalotes clypeatus Fabricius (Hymenoptera: Formicidae): hábitos de nidificação e ocorrência em carcaça animal

The ecological position of the family Formicidae in animal carcasses varies from predator, when feeding on eggs, larvae and pupae of some insects to necrophagous, when the ants feed on exudates or decomposing tissues. Ants are present in human corpses subject to forensic analyses and can also be used in estimation of the post-mortem interval (PMI). Cephalotes clypeatus Fabricius is exclusively arboricolous and occurs only in the American continent. During a field study conducted in the Campus of the Universidade Estadual de Campinas, in December 2003, a laboratory mouse carcass weighing 35,9 g was placed in an iron-mesh cage, which was adequate to collect adult ants. The carcass decomposed in four days. The total of 82 specimens of C. clypeatus was collected, in the first two days of exposure. They were observed feeding on exudates, tissues of the carcass, and on Diptera larvae occurring in the carcass. This species was observed nesting in hollow branches of Senna multijuga (Rich.) H.S. Irwin & Barneby (Caesalpinaceae), which was found one-meter far from the cage. Further investigation on the biology of this Cephalotini must be performed, in order to understand the role of this species in the utilization of animal carcasses, and in the entomological succession process as well. This is the first report of C. clypeatus in animal carcasses.

Description of the Immatures of Workers of the Ant Camponotus vittatus (Hymenoptera: Formicidae)

ABSTRACT Camponotus vittatus Forel is a poorly studied Neotropical ant, which is very common in Brazil. Larval descriptions are useful to systematics, as larval characters aid with genus-level differentiation, and ant larvae lie at the basis of ant social organization. This study presents the first description of the immatures of C. vittatus with the aid of light and scanning electron microscopy. There are three instars based on the frequency distribution of larval head widths. The larvae had some characteristics typical of Camponotus, specifically, a ‘pogonomyrmecoid’ body shape, 10 pairs of spiracles, antennae with 3 sensilla, mature larvae with pronounced labial pseudopalps, and conspicuous ‘chiloscleres’ on the labrum. Unique characteristics found would include the greatest diversity of body hair types recorded in an ant larva and ‘camponotoid’ mandibles with 6 medial denticles over the blade. The number of antennal sensilla proved variable.

Ants (Hymenoptera: Formicidae) Collected with Carrion-Baited Traps in Southeast Brazil

Ants can both feed on vertebrate carrion and prey upon other arthropods inhabiting corpses. An investigation using carrion-baited traps was conducted in three environments (rural, urban, and forest) in six municipalities of southeast Brazil, from September 2006 to October 2007. We collected 113 specimens of ants from the subfamilies Dolichoderinae, Myrmicinae and Formicinae. Bait and environmental associations of ants and potential forensic implications of their actions are discussed.

Intraguild predation influences oviposition behavior of blow flies (Diptera: Calliphoridae).

The objective of the present study was to determine whether blow flies (Diptera: Calliphoridae) are able to identify larvae of an intraguild predator species in the substrate and avoid laying eggs there. Blow flies oviposited in traps with different treatments: substrate only and substrate with larvae of Chrysomya albiceps (Wiedemann, 1819), Chrysomya megacephala (Fabricius, 1794), or Chrysomya putoria (Wiedemann, 1830). Ch. megacephala, Ch. putoria, and Lucilia eximia (Wiedemann, 1819) avoided laying eggs in the trap containing Ch. albiceps larvae. Cochliomyia macellaria (Fabricius, 1775) did not oviposit differently in each substrate but had overall low abundance. The prevalence of species on corpses may be influenced by the ability of the species to detect the presence of other species, mainly predators. In this sense, intraguild predation may result in misinterpretations of a crime scene and should be considered when assessing the minimum postmortem interval.

Effect of Psychoactive Drugs on Demographic Parameters of the Blow Fly Chrysomya albiceps (Wiedemann) (Diptera: Calliphoridae)

Knowledge of the factors influencing the ecology of blow flies, especially the dynamic population equilibrium, is essential in forensic entomology. However, lack of knowledge of the action of psychoactive drugs on the population dynamics of these flies may affect the inferences that experts must make in medico-legal reports. This study evaluated the effects of amphetamine and phenobarbital on the population dynamics of Chrysomya albiceps (Wiedemann), by combining laboratory experimentation and mathematical modelling. Only amphetamine and its control, methanol, influenced the qualitative dynamic behaviour of Chrysomya albiceps, stabilising chaotic populations. The results are discussed in an ecological and forensic context.