Biology and life cycle of Amblyomma incisum (Acari: Ixodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acquisition and transmission of Hepatozoon canis (Apicomplexa: Hepatozoidae) by the tick Amblyomma ovale (Acari: Ixodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atividade predatória de Euseius citrifolius Denmark & Muma (Acari: Phytoseiidae) sobre Tenuipalpus heveae (Acari: Tenuipalpidae)

The rubber tree red false spider mite, Tenuipalpus heveae Baker, is an important pest of Hevea brasiliensis (Willd. ex. Adr. de Juss.) Muell. Arg. The phytoseiid mite Euseius citrifolius Dennmark & Muma has frequently been recorded on rubber tree crops. The objective of this work was to determine the predatory activity of E. citrifolius on the different life stages (egg, larva, nymph and adult) of T. heveae. The experiments were carried out in Petri dishes (9-cm diameter) containing a layer of wet cotton inside, onto which a disk of rubber tree leaf (2.5-cm diameter) was laid. The disks were taken from naturally infested leaves. Twenty specimens in the life stage that was to be tested were left on the disk and the others were eliminated; a predator life stage (larva, nymph or female) was obtained from a laboratory stock colony and put into each dish. For each tested life stage of E. citrifolius, 4 treatments (T. heveae life stages) and 20 replications were considered in a randomized block design. The observations were made after 24 hours for larvae and nymphs of the predator, and after 24, 48 and 72 hours for the females. E. citrifolius larvae and nymphs had a higher preference for T. heveae larvae followed by nymphs, eggs and adults. Within 72 hours, each predator female consumed 15.0 larvae, 14.5 nymphs, 7.4 adults or 2.2 eggs of T. heveae. It is concluded that E. citrifolius can feed on red false spider mites, the larva and nymph being the preferred stages.

Two new species of Bdellidae (Acari : Prostigmata) from Brazil

Two new species, Bdella ueckermanni n. sp. and Spinibdella denheyeri n. sp. (Acari: Bdellidae), are described from plants in southeastern Brazil.

Histopathology of Rhipicephalus sanguineus (Acari: Ixodidae) ticks fed on resistant hosts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new species of Galendromus (Acari : Phytoseiidae): A case of intraspecific variation and redefinition of carinulatus species group

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cutaneous hypersensitivity induced in dogs and guinea-pigs by extracts of the tick Rhipicephalus sanguineus (Acari: Ixodidae)

The cutaneous hypersensitivity induced by Rhipicephalus sanguineus tick extract in dogs (natural host) and guinea-pigs (laboratory host) was evaluated. The left ear of infested and control (tick-bite naive) dogs and guinea-pigs was injected intradermally with an extract from unfed adult ticks and the right ear with phosphate buffered saline (PBS). Ear thickness variations were then measured after 10 min and 1, 2, 6, 18, 24, 48, 72 and 96 h post-injection. Results were expressed as percentual changes in the ear thickness in relation to pre-inoculation values. The final variation in ear thickness induced by the extract was given by subtracting, in each animal, the right ear percentual increase from that of the left ear. Guinea-pigs were tested at two different times following infestation and with two different doses of extract. Infested guinea-pigs from the three experiments developed an immediate (within the first 2 h post-inoculation) and a strong delayed reaction (24 h) to the extract. Dogs, unlike guinea-pigs, developed only a strong immediate reaction whereby an 80% increase in ear thickness was observed. Control animals, with the exception of one dog, did not develop any significant reaction to the extract. Only mild reactions were induced by PBS in the right ear of all animals. The correlation between the absence of a strong delayed type reaction to tick extract and the lack of resistance of the natural host to R. sanguineus tick is discussed. © 1995 Chapman & Hall.

Biologia de Polyphagotarsonemus latus (Banks, 1904) (Acari: Tarsonemidae) em algodoeiro

Leaf discs obtained from the first or second non-cotyledonal leaf of cotton (Gossypium hirsutum L.) seedlings were used for the study of the biology of Polyphagotarsonemus latus on cotton IAC-20 cultivar. Seedlings were grown in pots and placed on a layer of cotton moistened with distilled water. The assays were carried out at 28.5 ± 0.3°C, relative humidity of 71.0 ± 2.6% and a 14 h photophase. The duration of immature phases was 4.1 ± 0.1 days for females and 4.1 ± 0.3 days for males, with a survival of 91.2%. After a pre-oviposition period of 1.1 ± 0.2 days, the females deposited 4.5 ± 0.9 eggs per day during 6.8 ± 1.3 days, i.e., 29.6 ± 7.3 eggs per female. The longevity was 10.0 ± 1.5 days for females and 8.8 ± 1.1 days for males. The intrinsic rate of increase (rm) was 0.323; finite rate of increase (λ) 1.38 individual per female per day; mean generation time (T) 9.54 days and net reproductive rate (Ro) 21.73.

Four new Neotetranychus Trägardh (Acari: Tetranychidae) from São Paulo State, Brazil

Neotetranychus peniculus Aranda n. sp. from Bauhinia holophylla (Fabaceae), N. rhaphidoseta Aranda n.sp from Tabebuia ochraceae (Bignoniaceae), N. granifer Feres and Flechtmann n. sp. from Bauhinia forficata and N. asper Feres and Flechtmann n. sp. from Alchornea glandulosa (Euphorbiaceae) from São Paulo State, Brazil, are described and figured.

Ticks (Acari: Ixodidae) associated with wild animals in the Pantanal region of Brazil

This paper describes the identification of ticks from wild animals of the Pantanal region in Brazil as part of a comprehensive study about established and emerging tick-host relationships and related pathological aspects. Eighty-one animals were captured (representing 13 species six orders), and ticks were found on 63 (78%). Tick species identified included Boophilus microplus (Canestrini), Amblyomma cajennense (F.), Amblyomma parvum Aragão, Amblyomma pseudoconcolor Aragão, Amblyomma scalpturatum Neumann, Amblyomma nodosum Neumann, Amblyomma ovale Koch, and Amblyomma tigrinum Koch. Dragging from grasslands yielded negative results compared with the high concentration of ticks that were collected from leaves in the forests.

Quasilinear dirichlet problems in RN with critical growth

In this study, a given quasilinear problem is solved using variational methods. In particular, the existence of nontrivial solutions for GP is examined using minimax methods. The main theorem on the existence of a nontrivial solution for GP is detailed.

Susceptibility of the cattle tick Boophilus microplus (Acari: Ixodidae) to isolates of the fungus Beauveria bassiana

The susceptibility of the tick Boophilus microplus to Beauveria bassiana was evaluated by inoculating eggs, larvae and engorged females of the tick with five fungal isolates at concentrations of 106, 107 and 108 conidia/ml. Tick eggs (0.25 g) were immersed in 1 ml of a suspension of the different conidial concentrations for 1 min. Similar exposure was performed by immersion of 2000 larvae and homogeneous groups of nine engorged females in 2 and 20 ml of conidial suspension, respectively. Treated eggs, larvae and adults were placed in an incubator at 27 ± 1 °C and relative humidity above 80% for evaluation of the fungal action. All fungal isolates applied at all conidial concentrations reduced the hatching rate of larvae from treated eggs by 1.36-65.58% and increased the mortality rate of inoculated larvae by 0.8-70.49%. In the bioassay with engorged females, oviposition period was reduced by 9.69-47.80%, egg mass weight by 4.71-53.87%, estimated reproduction by 8.3-60.62%, egg production index by 5.03-54.20%, percent larval hatching by 0.27-13.96%, and the mortality rate of treated females was increased by 96.60-100%. The reduction of the estimated reproduction obtained for the treated groups ranged from 8.37 to 64.52%. The sporulation of the pathogen on dead females ranged from 3.70 to 88.88% depending on the isolate and concentration used. Isolates AM 09, CB 7 and JAB 07 were the most effective and effectiveness increased with increasing concentrations of conidia in the suspensions.

Ticks (Acari: Ixodidae) associated with domestic dogs in Franca region, São Paulo, Brazil

Ticks on 140 domestic dogs from both urban and rural areas of Franca region in São Paulo state were identified with 102 dogs from urban areas and 38 from rural areas. Of urban dogs, 27.5% were infested exclusively by Rhipicephalus sanguineus ticks. Of the rural dogs, 36.8% were infested with the following tick species: R. sanguineus, Boophilus microplus, Amblyomma ovale and A. cajennense. Mixed infestations included a dog hosting A. cajennense and A. ovale and another with B. microplus and R. sanguineus. The most intense infestations were detected on urban dogs. Hemolymph tests of these ticks performed to detect rickettsial or Borrelia bacteria yielded negative results.

Ticks (Acari: Ixodidae) on Wild Marsh-Deer (Blastocerus dichotomus) from Southeast Brazil: Infestations before and after Habitat Loss

The lake from Porto-Primavera hydroelectric power station inundated an area of 2,200 km2 at the border of São Paulo and Mato-Grosso do Sul States, Brazil. Infestations by ticks were evaluated on 135 marsh deer, Blastocerus dichotomus (Illiger), captured before and after inundation. Ticks were collected for identification, and infestation level of animals was assessed by scoring. Deer were divided into four groups according to capture location and temporal relation to the inundation. Groups 1, 2, and 3 were captured before inundation. Group 4 was captured after inundation. Four tick species were found: Amblyomma cajennense (F.), Amblyomma triste Koch, Anocentor nitens (Neumann), and Boophilus microplus (Canestrini). Groups 1, 2, 3, and 4 had 30, 45, 100, and 96%, respectively, of animals carrying B. microplus ticks. A. triste was observed on 16, 22, 22, and 88% of animals from groups 1,2,3, and 4, respectively. A. nitens and A. cajennense were observed only on group 4, on 32 and 16% of the animals, respectively. Groups 1 and 2 had only 4.8 and 6.1% of animals with high infestation levels, respectively, and no ticks on 46.8% and 45.5% of the animals, respectively. Conversely, groups 3 and 4 lacked noninfested animals and had high infestation levels on 77.8 and 50% of deer, respectively. Marsh area shrinkage was blamed for higher infestation levels on deer from groups 3 and 4. The widespread presence of A. triste on marsh deer, a Neotropical tick species, raises the possibility of a natural host-parasite relationship.

Two new species of Zetzellia Oudemans (Acari: Stigmaeidae) that threaten the concept of genera: Disgeneric marriage?

Two new species of Zetzellia Oudemans, Z. agistzellia sp. n. and Z. quasagistemas sp. n., are described from rubber trees of northwestern São Paulo State, Brazil. Females have clear features of Zetzellia, whereas males resemble Agistemus in some characters. Immatures are also described. The discovery of these species raises some problems concerning generic concepts in Stigmaeidae. Since features of different genera are present in the same species, the authors suggest that the scope of those genera should be reviewed. Copyright © 2005 Magnolia Press.