Caio Domingues | UFSCar - Federal University of São Carlos (original) (raw)

Papers by Caio Domingues

Larvae of honeybee workers were exposed to the insecticide fipronil during the feeding phase. To ... more Larvae of honeybee workers were exposed to the insecticide fipronil during the feeding phase. To evaluate the effect of fipronil in the post-embryonic development of africanized Apis mellifera, bioassays of toxicity were done. The bioassays were performed by acute exposure applying 1μL of distilled water for control (I) and for experiments: 0.5 ng a.i./μL of fipronil; 5 ng a.i./μL of fipronil and 20 ng a.i./ μL of fipronil. Triplicates were performed for all treatments. The results showed that the rate of anomalous pupae in exposed honeybees was statistically significant in relationship to the control (p <0:03). The most frequent abnormalities were: high pigmentation on the proximal and distal larval body and body malformation, such as absence of head and limbs. Pink eye pupa and white eyed pupae presented malformations in their larval bodies, but with the eye developed. It is assumed that the fat body is related to the high rate of anomalies, since this tissue has proteins linked to the process of metamorphosis. Furthermore, the fat body may be participating in the regulation of juvenile hormone during the process of metamorphosis, and consequently in the
release of ecdysteroid hormones that are involved in the change from larva to adult. The high rate of abnormalities in the pupal stage of individuals exposed to fipronil raises concerns about the impacts caused in the colonies of bees and population decline of pollinators.

Bombus presents a serious global decline of populations and even loss of species. This phenomenon... more Bombus presents a serious global decline of populations and even loss of species. This phenomenon is complex and multifactorial: environmental degradation due to increasing
cultivation and grazing areas, indiscriminate use of agrochemicals, and a plethora of xenobiotics daily discharged in the environment.We proposed that bees have an integrated cell
system, which ensures protection against chemical stressors up to a certain limit. Therefore, this hypothesis was tested, exposing workers of Bombus morio to cadmium, a harmful
trace metal nowadays widespread in our society. The workers were kept in BOD (26°C, RH 70%, in the dark), fed ad libitum, and divided into a control group (n = 20) and an experimental
group (n = 20). For the first group, we offered 2 mL of distilled water; for the experimental groups, 2mL of cadmium at 1 ppb. In relation to the control group, exposed bees showed that their fat body and hemocytes responded in synchronization with pericardial cells in a topographical and temporal cascade of events, where the fat body is the first barrier against xenobiotics, followed by pericardial cells. The immune cells participate throughout the process. To this system, we proposed the name of hepato-nephrocitic system (HNS), which
may explain many phenomena that remain unclear in similar research with Apis mellifera and other species of bees, as shown in this paper. The bee’s HNS is a system of highly
responsive cells to toxicants, considered a novel parameter for the study of the ecology of stress applied in environmental management.

Larval development of Physocephala (Diptera, Conopidae) in the bumble bee Bombus morio (Hymenopte... more Larval development of Physocephala (Diptera, Conopidae) in the bumble bee Bombus morio (Hymenoptera, Apidae). In the summer of 2012, a high incidence of conopid larvae was observed in a sample of female B. morio collected in remaining fragments of semidecidual forest and Cerrado, in the municipality of Sorocaba, state of São Paulo, Brazil. The larval development of conopid flies was studied, beginning at the larval instars (LO to L3) and PUP, until the emergence of the imago under laboratory conditions and inside the host. At the first instar, or LO, the microtype larvae measured less than 1 mm in length. During the transition from L1 to L3, the larvae grew in length. At L3, the larvae doubled their length (4 mm) and then started to develop both in length and width, reaching the PUP stage with 10 mm in length and 7 mm in width. The main characteristic that differentiates L3 from the early instars is the larger body size and the beginning of posterior spiracle development. The development from PUP to puparium took less than 24h. The bees died ten days after the fly oviposition, or just before full PUP development. The early development stages (egg-LO to L1) were critical for larva survival. The pupa was visible between the intersegmental sternites and, 32 days after pupation, a female imago of Physocephala sp. emerged from one bee. The puparium and the fly measured approximately 10 mm in length. In a single day of collection, up to 45% of the bumble bees collected were parasitized by conopid flies.

CAMPUS DE SOROCABA ESTADO DE SÃO PAULO SOROCABA, 2014 UNIVERSIDADE FEDERAL DE SÃO CARLOS Campus d... more CAMPUS DE SOROCABA ESTADO DE SÃO PAULO SOROCABA, 2014 UNIVERSIDADE FEDERAL DE SÃO CARLOS Campus de Sorocaba Rodovia João Leme dos Santos, km 110, SP 264 -Itinga. Cx.Postal 3031-CEP 18052-780-Sorocaba -SP -Brasil Fone 0XX15-3229-6000 (PABX) Home page: http://www.ufscar.br 1. FUNÇÃO, ORGANIZAÇÃO E ESTRUTURA CELULAR (ESTA ATIVIDADE EQUIVALE A UMA AVALIÇÃO TEÓRICA COM PESO 1) Instruções FORMAR GRUPOS DE 5 PESSOAS