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During 1992, the population dynamics of rabbit fleas were compared at two sites in north-eastern Spain. The sites differed mainly in terms of annual rainfall and soil type. All flea species showed seasonal cycles of abundance, although peaks in numbers occurred at different times, reflecting their specific adaptations for coping with climatic variables. Adult Spilopsyllus cuniculi (Dale) (Siphonaptera: Pulicidae) were found largely parasitizing rabbits in spring and adult Caenopsylla laptevi (Beaucournu etal.) (Siphonaptera: Ceratophyllidae) in the autumn. In contrast, monthly flea indices of Xenopsylla cunicularis (Smit) (Siphonaptera: Pulicidae) and Echidnophaga iberica (Ribeiro et al.) (Siphonaptera: Pulicidae) peaked in summer. Spilopsyllus cuniculi was present at both sites, but was less common on the drier site, where monthly mean temperature and annual rainfall approached the flea's physiological limits. By contrast, E. iberica, X. cunicularis and C. laptevi, known to be better adapted for dryness, showed the opposite patterns of abundance. Nevertheless, even these arid-adapted species took advantage of the milder and wetter spring (X. cunicularis and E. iberica) or autumn (C. laptevi) for breeding and larval development. Although environmental temperature, rainfall and soil texture will influence the microclimate of the burrows where the flea larvae develop, burrow humidity seems to be more dependent on soil characteristics and past rainfall rather than the humidity of the external air.

Since myxomatosis, around half a million rabbits are restocked annually in France and the Iberian Peninsula. The effectiveness of this approach to restoration is still unknown. In this study, the efficacy of traditional restocking was evaluated by marking rabbits with radiocollars and reproducing the methodology usually employed in Spain. The estimated mean survival rate for the first 10 days after release was very low (

The tick species commonly collected at the Northeast of Spain are reported in this paper. Data on hosts, temperature and humidity requirements, vegetation relationships, altitudinal distribution, and seasonal activity are included. R. sanguineus is commonly collected in areas with Mediterranean vegetation, esteppe, and semi- desertic esteppe, ranging from 190 to 1,000 meters above the sea level. R. sanguineus is related with sparse vegetal areas, and it is absent from areas with dense shrub or forests of every kind; sometimes, small populations may be collected in ecotones between Pinus spp. and esteppe formations. R. pusillus is closely related to areas of Mesomediterranean vegetation, sometimes subordinate to Pinus spp. and Quercus spp. The climate to which the species ally is always of continental type, with a hot and dry summer, and cold winter; although the species is commonly restricted to its main host, Oryctolagus cuniculus , several specimens have been collected from V. vulpes. Our data display the clear affinity of I. ricinus to the Supramediterranean vegetation (Aceri-Quercion faginae), places of Quercetum-Buxetum, as well as the Iberian Oromediterranean vegetation (Pinus sylvestris-Buxus sempervirens). Captures are scarce in forest of Fagus sylvatica , but data suggest that the species may be locally common on such places. Climate for the zones of collection of I. ricinus is Atlantic attenuated, with mild summers and humid winters. D. marginatus is strongly related to the xerophilic vegetation, widely spread through the Mediterranean, Supramediterranean, and hill levels, but does not colonize the true Oromediterranean vegetation. In our captures, the species is commonly collected in pubescent oak formations, but it does not penetrate in true forest associations. H. punctata breeds commonly on the Supramediterranean stage, clearly associated to Quercus spp., in wet areas. Both immature and adult stages of I. frontalis have been collected in areas of river vegetation (with hot and semi-dry summers, and mild winters, approx. 200 meters above the sea level) and in all the stages of the Mediterranean vegetation (meso-, supra- and oromediterranean). New host records are provided for both H. punctata and I. frontalis in Spain. Data are also reported for species scarcely collected, as H. hispanica, R. bursa, I. trianguliceps, and I. canisuga.

The capture and handling of live European wild rabbits (Oryctolagus cuniculus) are unavoidable initial steps for immunization by vaccination against viral hemorrhagic disease (VHD) and myxomatosis as a management tool aimed at enhancing wild rabbit populations. We investigated the short-term effects of vaccination campaigns against VHD and myxomatosis on the survival of 206 European wild rabbits in a Spanish population. While no effect was observed on the survival of adult rabbits, young and subadult rabbits (P < 0.001) had higher mortality rates during the first week after handling than in the subsequent 3 weeks. The hazard rate of death from disease was inversely correlated with body condition (P < 0.001) during the first week. Vaccination increased the hazard rate of death due to disease during the first 7 days post-handling, although this detrimental effect was higher in young rabbits (P = 0.012) and modulated by body condition (P = 0.004). The hazard rate of dying from predation during the first week was higher for males than females (P = 0.023) and in subadults compared to young rabbits (P = 0.004). Body condition was inversely related to the predation hazard rate (P = 0.002). Our results suggest that vaccination campaigns had a short-term negative impact caused by the stress of handling in addition to the detrimental effects of vaccination against VHD and myxomatosis. Future studies should consider this negative impact to assess the true efficacy of vaccination campaigns in wild populations., This study was funded by the Dirección General de Medio Natural (Gobierno de Aragón).

The male holotype and female allotype of Echidnophaga iberica Ribeiro, Lucientes, Osacar & Calvete, a new species of rabbit flea from the Zaragoza area, northeastern Spain, is described on the basis of examination of a type series of six males and 13 females. Similarities of the new species with other species of the genus Echidnophaga are discussed and a key to identification of the four known Mediterranean species of the genus is provided.

From January 1993 to June 1996, the epidemiology of myxomatosis and viral haemorrhagic disease (VHD) was studied in a free-living population of wild rabbits (Oryctolagus cuniculus ) in Spain by means of serological surveys and radiotracking. Myxomatosis was endemic and associated with the breeding period. Its serological pattern was characterised by a 100 per cent prevalence of antibodies in adult rabbits and a rapid increase in antibodies in young rabbits in their first year. No mortality from myxomatosis was detected in adults, and mortality in young rabbits could not be estimated because of interference by predators and scavengers and the deaths of many radiotagged rabbits inside their burrows. VHD was also an endemic disease associated with the breeding period. Adults had a higher prevalence of antibodies against VHD than young rabbits, teaching values of 80 to 90 per cent. During the study, there was an increase in rabbit numbers as a result of a decrease in mortality from predation which was associated with an increase in mortality due to VHD and in the prevalence of antibodies to VHD. Mortality from VHD was lower in rabbits with VHD antibodies than in seronegative rabbits, but some mortality from the disease was also detected in seropositive rabbits. The annual mean mortality rate due to VHD in adult rabbits was estimated to be 21.8 per cent., Funding was provided by the Dirección General de Medio Natural (Gobierno de Aragón) and a postdoctoral fellowship from CSIC-Junta de Andalucía (IFD97–2299) to C. C.

During 1992, the population dynamics of rabbit fleas were compared at two sites in north-eastern Spain. The sites differed mainly in terms of annual rainfall and soil type. All flea species showed seasonal cycles of abundance, although peaks in numbers occurred at different times, reflecting their specific adaptations for coping with climatic variables. Adult Spilopsyllus cuniculi (Dale) (Siphonaptera: Pulicidae) were found largely parasitizing rabbits in spring and adult Caenopsylla laptevi (Beaucournu etal.) (Siphonaptera: Ceratophyllidae) in the autumn. In contrast, monthly flea indices of Xenopsylla cunicularis (Smit) (Siphonaptera: Pulicidae) and Echidnophaga iberica (Ribeiro et al.) (Siphonaptera: Pulicidae) peaked in summer. Spilopsyllus cuniculi was present at both sites, but was less common on the drier site, where monthly mean temperature and annual rainfall approached the flea's physiological limits. By contrast, E. iberica, X. cunicularis and C. laptevi, known to be better adapted for dryness, showed the opposite patterns of abundance. Nevertheless, even these arid-adapted species took advantage of the milder and wetter spring (X. cunicularis and E. iberica) or autumn (C. laptevi) for breeding and larval development. Although environmental temperature, rainfall and soil texture will influence the microclimate of the burrows where the flea larvae develop, burrow humidity seems to be more dependent on soil characteristics and past rainfall rather than the humidity of the external air.

This paper reports the annual dynamics of wild rabbit fleas in a study site located in the Middle Ebro Valley, northeastern Spain. Fleas collected directly from wild rabbits included the species Spilopsyllus cuniculi (Dale), Xenopsylla cunicularis (Smit), Echidnophaga iberica (Ribeiro, Lucientes, Osacar, and Calvete), Caenopsylla laptevi (Beaucournu, Gil-Collado and Gilot), and Pulex irritans (L.). Monthly collections of adult and larval fleas made from within the first meter of selected burrow entrances also yielded fleas belonging to the same five species. Larval specimens of X. cunicularis, E. iberica, and C. laptevi were also found. Spilopsyllus cuniculi, a winter species that can only breed during the rabbit breeding season, was common on hosts from November to April. Xenopsylla cunicularis and E. iberica were summer species, whereas C. laptevi was abundant during the autumn and winter. Xenopsylla cunicularis and E. iberica larvae were found in burrows only during April and May, whereas those of C. laptevi were collected from October to January. The data suggested that X. cunicularis and E. iberica might diapause during the egg stage whereas C. laptevi diapauses during the pupal stage.

The prevalence of Borrelia burgdorferi sensu lato in several tick species was studied over a 2 year period in two ecologically different areas in Spain. One area was an endemic area for Lyme disease, with a number of autochthonous human cases and supported large populations of Ixodes ricinus on cattle and birds; the second area was characterized by the absence of I. ricinus together with the presence of foxes and their associated tick species. While I. ricinus was the main vector of B. burgdoreri in the endemic area (with a mean prevalence of 14% in adults and 51% in nymphs), adults of both Ixodes canisuga and Ixodes hexagonus had high rates of B. burgdorferi prevalence (30 and 28%, respectively) in the zone where I. ricinus was absent. Immatures of Ixodes frontalis were found to be carriers of the spirochete only in those zones where I. ricinus is present, suggesting evidence for reservoir competence in a tick-bird cycle.

We looked for louse flies (Diptera, Hippoboscidae) in a mixed colony of 9 species of birds from 1991 to 1997. Alpine swifts (Apus melba) exhibited an unusually high prevalence (85.9%) by Crataerina melbae (Rondani, 1879). No birds from the other 8 breeding bird species were parasitized by this louse fly. We suggest that the number of potential swiftlike hosts as well as the size of hosts may account for the differential prevalence of the louse flies within the colony.