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PubMed2000

Reduction in fitness of flea beetles which are homozygous for an autosomal gene conferring resistance to defences in Barbarea vulgaris.

Major resistance genes are present in Danish flea beetle (Phyllotreta nemorum) populations, enabling the beetles to utilize a defended plant, Barbarea vulgaris ssp. arcuata, as a host plant, whereas this plant is unsuitable for beetles lacking the resistance genes. Two lines of beetles carrying a resistance gene have been established which are near-isogenic with a susceptible line. Larval survival of offspring from crosses between flea beetles carrying resistance genes and susceptible beetles, tested in bioassays on the defended B. vulgaris, and sex ratios of the survivors, were consistent with the presence of a dominant, autosomal resistance gene in each of the lines. An attempt to produce pure-breeding lines for the autosomal genes revealed that beetles that are homozygous for the resistance gene suffer a high mortality. This result was repeatable for both lines, and when both resistant males and females were used in the crosses. The high mortality was also independent of the plant (defended B. vulgaris or suitable radish) on which the beetles were reared. The results suggest that the time of death of homozygous resistant beetles is variable. The spread and maintenance of resistance genes in flea beetle populations are discussed.

Animals↗
PubMedDate not supplied

[Neoparasitylenchus megabothridis n. sp. (Tylenchida: Allantonematidae) parasite of Megabothris tubidus (Siphonaptera: Ceratophyllidae); observations on fleas tylenchides in the S.W. of Europa (author's transl)].

A number of nematodes (Tylenchida, Allantonematidae) were observed in 11 species of Siphonaptera from the South-West of Europe. The fleas belong of 4 differents families (Pulicidae, Vermipsyllidae,Hystrichopsyllidae, Ceratophyllidae). Neoparasitylenchus megabothridis n. sp., parasite of the flea Megabothris turbidus (Rothschild, 1909), is described and the life cycle given. It shows little pathogenicity to tis host. Psyllotylenchus sp. parasite of Nosopsyllus fasciatus (Bosc, 1801), appears to be a teratogenic and causes a feminisation of parasitised males and a masculinisation of females. A generic determination cannot be made with any certainty in the material collected from others fleas.

Animals↗
PubMed2002

The effect of substrate on survival and development of two species of desert fleas (Siphonaptera: Pulicidae).

Fleas Xenopsylla conformis mycerini and Xenopsylla ramesis replace each other on the same rodent host (Meriones crassus) in two habitats that differ in substrate texture (sand and loess-like sediments, respectively). We hypothesized that the substrate is an important factor determining flea distribution and studied survival of larvae, pupae and newly emerged adults as well as the rate of pre-imaginal development of these flea species in sand and loess rearing medium (= substrate). Texture of rearing medium did not affect survival and development rate of eggs in either X. c. mycerini or X. ramesis. Larval survival and the rate of development were both affected by the factor of substrate. Survival of X. c. mycerini larvae was significantly higher in sand than in loess substrate, whereas survival of X. ramesis larvae did not differ in different substrates. Larvae of both species developed faster in sand substrate than in loess substrate. Maximal survival time of X. c. mycerini larvae that died before pupation did not depend on substrate, whereas X. ramesis larvae survived significantly longer in loess than in sand substrate. Most pupae of both species survived successfully on both substrates, but the duration of pupal stages in sand substrate was longer than that in loess substrate in both species. Newly emerged adults of both species survived similar time in both sand and loess substrate. Irrespective of substrate, adult X. c. mycerini survived for a shorter time than did adult X. ramesis. No between-sex within-species differences in survival time of newly emerged adults in sand versus loess substrate were found in X. c. mycerini. Survival time of males and females of X. ramesis differed in sand substrate but not in loess substrate.

Animals↗
PubMed2006

Three new fleas from Sulawesi, Indonesia (Siphonaptera: Pygiopsyllidae & Ceratophyllidae).

Gryphopsylla maxomydis n. sp. (Pygiopsyllidae), Medwayella rubrisciurae n. sp. (Pygiopsyllidae) and Macrostylophora theresae n. sp. (Ceratophyllidae) are described from endemic rodents in Sulawesi. Gryphopsylla maxomydis was collected from the murids Maxomys musschenbroekii and Paruromys dominator in Central Sulawesi (Sulawesi Tengah). However, M. musschenbroekii appears to be the true host of this flea because it has spiny pelage and G. maxomydis shows morphological adaptations for parasitizing spiny hosts including a remarkable "beak-like" structure on the head. This adatation is similar to a beak-like structure on the head of Gryphopsyllo hopkinsi (Traub) which parasitizes the spiny murid Maxomys whiteheadi in Borneo (Sabah). Medwayella rubrisciurae was collected from the large tree squirrel Rubrisciurus rubriventer in Central Sulawesi and this represents the first report of this flea genus in Sulawesi. Macrostylophora theresce was recorded from the murids Bunomys fratrorum, P. dominator and Rattus xanthurus in North Sulawesi (Sulawesi Utara); most other members of this flea genus parasitize squirrels in the Oriental and Palaearctic zoogeographical regions.

Adaptation, Physiological↗
PubMed1992

Genetic characterization and transovarial transmission of a typhus-like rickettsia found in cat fleas.

The identification of apparently fastidious microorganisms is often problematic. DNA from a rickettsia-like agent (called the ELB agent) present in cat fleas could be amplified by PCR with conserved primers derived from rickettsial 17-kDa common protein antigen and citrate synthase genes but not spotted fever group 190-kDa antigen gene. Alu I sites in both the 17-kDa and citrate synthase PCR products obtained with the rickettsia-like agent and Rickettsia typhi were different even though both agents reacted with monoclonal antibodies previously thought specific for R. typhi. The DNA sequence of a portion of the 17-kDa PCR product of the rickettsia-like agent differed significantly from all known rickettsial sequences and resembled the 17-kDa sequences of typhus more than spotted fever group rickettsiae. The rare stable transovarial maintenance of this rickettsia in cat fleas has important implications for the disease potential of cat fleas.

Animals↗
PubMed1984

A survey of cats and dogs for fleas: with particular reference to their role as intermediate hosts of Dipylidium caninum.

Three species of fleas, viz. Ctenocephalides felis, Ctenocephalides canis, and Pulex irritans were found in an examination of 81 cats and 48 dogs in Wellington. C. felis was the most prevalent flea in cats, and C. canis predominated in dogs. It is speculated that C. felis, and its primary host the cat, may assume greater medical and veterinary significance than C. canis. In an examination of 1578 fleas for cysticercoids of the dog tapeworm, Dipylidium caninum, all were found negative. These results do not necessarily reflect the availability of cysticercoids in the environment, and the reasons for this are discussed.

Journal Article↗
PubMed1990

Investigations on the role of flea antigen in the pathogenesis of German shepherd dog pyoderma (GSP).

Skin reaction patterns to the intradermal injection of a whole-body flea extract were examined in five physically healthy dogs and in 24 dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 8, 24, 48 and 72 hours after the injection. In 10 out of 24 GSP dogs a positive skin reaction was observed macroscopically after 15 minutes. Delayed reactions at 24 or 48 hours were not observed. In the control group neither immediate nor delayed reactions were observed. The histopathologic skin changes were basically the same in both groups: an initial polymorphonuclear reaction followed by a mononuclear cell reaction. In the GSP dogs, however, these changes occurred earlier and were more prolonged than in the normal dogs. No flea-antigen-specific IgGd antibodies could be demonstrated by enzyme-linked immunosorbent assay. It is concluded that delayed type hypersensitivity to flea antigen does not play a role in the pathogenesis of GSP. Immediate type hypersensitivity may contribute to the disease in some cases.

Animals↗
PubMed2005

Poor vector competence of fleas and the evolution of hypervirulence in Yersinia pestis.

Population genetics and comparative genomics analyses of the pathogenic Yersinia species have indicated that arthropodborne transmission is an evolutionarily recent adaptation in Yersinia pestis, the agent of plague. We show that the infectivity of Y. pestis to its most proficient vector, the rat flea Xenopsylla cheopis, and subsequent transmission efficiency are both low. The poor vector competence of fleas likely imposed selective pressure that favored the emergence and continued maintenance of a hypervirulent Y. pestis clone. In particular, the rapidly fatal gram-negative sepsis that typifies plague is a consequence of the high threshold bacteremia level that must be attained to complete the transmission cycle. Epidemiological modeling predicts that, to compensate for a relatively short period of infectivity of the mammalian host for the arthropod vector, plague epizootics require a high flea burden per host, even when the susceptible host population density is high.

Animals↗
PubMed1996

Activity of insecticides applied to turfgrass to control adult cat fleas (Siphonaptera:Pulicidae).

A bioassay was developed to determine the efficacy of insecticides against adult cat fleas, Ctenocephalides felis (Bouché), on turfgrass. Activity was assessed by exposing adult fleas to treated and untreated disks of turf for 24 h, 1 and 7 d after treatment. Filter paper, a representative nonwaxy, porous substrate was bioassayed in similar fashion 1 d after treatment to confirm insecticide activity. Results demonstrated the relative efficacy of insecticides applied to turf at different rates as well as differences among insecticides. Of 10 insecticides tested, chlorpyrifos wettable powder and emulsifiable concentrates consistently provided greatest kill of adult fleas. Although initially active, pyrethroid insecticides and diazinon generally showed significant declines in residual activity by day 7. Possible reasons for differences in activity are discussed.

Animals↗
PubMed1999

Effect of temperature and the synergist piperonyl butoxide on imidacloprid toxicity to the cat flea (Siphonaptera: Pulicidae).

The toxicity of imidacloprid to cat fleas on glass was investigated at 20, 26, 30, and 35 degrees C. Imidacloprid was most toxic to adult cat fleas at 35 degrees C and to larvae at 20 degrees C. Piperonyl butoxide (PBO), a synergist, increased the relative potency of imidacloprid (1:5 imidacloprid:PBO) 16-fold at 26 degrees C against adults, but had no effect at 35 degrees C. No synergism occurred in larvae at 20 degrees C, but addition of PBO (1:5 imidacloprid:PBO) doubled toxicity at 26 degrees C. PBO (1:5 imidacloprid:PBO) could possibly be used to synergize imidacloprid premise treatments (20-30 degrees C), but it is not likely to be effective in pet treatments because no synergism occurred in adult fleas at 35 degrees C (average fur temperature of tested cats and dogs).

Animals↗
PubMed1990

Field evaluation of Nylar for control of cat fleas (Siphonaptera: Pulicidae) in home yards.

Procedures were developed to evaluate juvenoid insect growth regulators in home yards as part of an ongoing program to identify photostable insecticides for control of the cat flea, Ctenocephalides felis (Bouché). Nylar, an emulsifiable concentrate formulation of pyriproxyfen, was selected as the experimental insect growth regulator. Efficacy studies, yard survey, and pretreatment sampling techniques are described. Soil samples collected from the yards at intervals after treatment were taken to the laboratory, infested with flea larvae, and tested for juvenoid activity. Results indicated that Nylar applied at a concentration of 32 mg/m2 in 0.82 liter of water/m2 (20 gal/1,000 ft2) prevented development of approximately 80% of the fleas for a period of 3 wk.

Animals↗
PubMed1990

Prevalence and biology of endosymbionts of fleas (Siphonaptera: Pulicidae) from dogs and cats in Alachua County, Florida.

A study was conducted to determine the prevalence and biology of endosymbionts in local populations of fleas collected from dogs and cats in Alachua Co., Florida. Four hundred three Ctenocephalides felis (Bouché), 194 Pulex simulans Baker, and 44 Echidnophaga gallinacea (Westwood) were examined. Fleas were collected from 52 dogs and 51 cats. From 1 to 20 fleas were dissected from each host. A variety of microorganisms and metazoa was observed, including a baculovirus, gram-negative bacteria, rickettsia-like organisms, amoebae, trypanosomatid flagellates, cephaline gregarines, and microsporidia. Microfilariae of the dog heartworm, Dirofilaria immitis, entomophilic nematodes, and metacestodes of the tapeworm Dipylidium caninum were also observed.

Animals↗
PubMed1992

Diel patterns of cat flea (Siphonaptera: Pulicidae) egg and fecal deposition.

The quantity of eggs and feces deposited by replicate populations of cat fleas, Ctenocephalides felis (Bouché), from domestic house cats. Felis catus, were recorded at 1-h intervals over a 24-h period, in a photoperiod of 12:12 (L:D) (photophase, 0600-1800 hours [EST]). Egg production averaged 23.96 +/- 0.83 eggs per female per day and was greatest from 2400 to 0300 hours and lowest from 0700 to 0900 hours and from 1700 to 1900 hours. Daily fecal deposition was 0.77 +/- 0.03 mg feces per flea and did not vary significantly among hours. Flea eggs and adult feces were dropped continuously from infested cats, but significantly more eggs were shed at times of day when cats normally rest. More feces are concentrated in the small areas where cats rest than over the large areas they roam. Consequently, eggs and feces would not be deposited uniformly throughout the hosts home range, resulting in a clumped distribution of larval development sites at host resting areas.

Animals↗
PubMed1992

Influence of photoperiod on egg production of cat fleas (Siphonaptera: Pulicidae) infesting cats.

Photoperiod affected the production of cat flea eggs by cats infested with cat flea, Ctenocephalides felis (Bouché). Cat flea eggs have a smooth chorion and do not adhere to the host. About 60% of fluorescing eggs placed in the pelage were recovered in collecting trays underneath the host in 2 h. An average of 87.7 eggs per cat was laid during the last 8 h of the scotophase compared with 49.9 and 59.1 eggs during the other 8-h periods. Significant variation in the number of eggs collected daily existed among the six cats. The activity budgets were similar for all the cats with the maximum sleep period during the photophase. The possible adaptive advantages of synchronizing egg production with photoperiod are discussed.

Animals↗
PubMed1993

Fleas (Siphonaptera) infesting giant kangaroo rats (Dipodomys ingens) on the Elkhorn and Carrizo Plains, San Luis Obispo County, California.

The giant kangaroo rat, Dipodomys ingens (Merriam), has a limited distribution in the San Joaquin Valley, CA. Because of reductions in its geographic range, largely resulting from humans, the species was listed as an endangered species in 1980 by the California Fish and Game Commission. As part of a study of the community ecology of southern California endangered species, including D. ingens, we were able to make flea collections from the rats when they were trapped and marked for population studies. All but one of the fleas collected from the D. ingens in this study were Hoplopsyllus anomalus, a flea normally associated with ground squirrels (Sciuridae). It has been suggested that giant kangaroo rats fill the ground squirrel niche within their range. Our data indicate that this role includes a normal association with Hoplopsyllus anomalus.

Animals↗
PubMed1995

Fleas on gray foxes in New Mexico.

From April 1992 to April 1993, fleas were collected from 15 gray foxes, Urocyon cinereoargenteus Schreber, in New Mexico. Flea species collected were Cediopsylla inaequalis inaequalis Baker (14/15), Echidnophaga gallinacea (Westwood) (1/15), Euhoplopsyllus glacialis affinis Baker (10/15), Foxella ignota Baker (1/15), Pulex irritans (L.) (6/15), and Pulex simulans Baker (15/15). C. i. inaequalis and F. ignota are new host records for gray foxes. The collection of C. i. inaequalis, E. g. affinis, F. ignota, and P. simulans are new host records for New Mexico. Fleas on gray foxes in the Southwest are reviewed.

Animals↗
PubMed1996

Egg production and emergence of adult cat fleas (Siphonaptera: Pulicidae) exposed to different photoperiods.

Laboratory cats were infested with a known number of cat fleas, Ctenocephalides felis (Bouché), to determine the effects of photoperiod on flea egg production. Photoperiods of 8:16, 12:12, and 16:8 (L:D) h were chosen to represent winter, spring/fall, and summer, respectively. There were no significant differences in daily or total flea egg production among the 3 photoperiods. To determine the effects of photoperiod on development of immature stages and subsequent adult emergence from cocoons, eggs collected during each photoperiod experiment were reared under the 3 described light and dark conditions. Resulting differences suggest that photoperiod may influence the emergence behavior of adults from cocoons.

Animals↗