Long term evaluation of factors influencing the association of ixodid ticks with birds in Central Europe, Hungary

Table 1 Total number of tick species and stages found during the study (2015–2022).

Altogether, 1872 (78.16%) of the captured, tick-infested birds carried I. ricinus, while 592 (24.72%) of them carried Ha. concinna. Ixodes frontalis was present on 51 birds (2.13%). The remaining seven tick species were carried by a combined total of 13 (0.54%) birds. One hundred thirty-one birds carried two tick species, and on one Song Thrush (Turdus philomelos) three different tick species were present simultaneously (I. ricinus, I. frontalis and Ha. concinna).

The 2395 tick-carrying birds captured during this study are summarized in Table 2, according to the characteristics that were examined. In the table, we also indicated how many bird species belonged to the given category. More detailed information can be found in Supplementary Tables 2 and 3.

Table 2 Total number of birds, and bird species found to be tick-infested between 2015 and 2022, according to their migration habit, habitat and feeding place.Number and temporal occurrence of tick species, their host associations according to habitat and migration characteristics

All tick-host associations are listed in Supplementary Tables 1 and 2 and visualized in Fig. 1 and Supplementary Fig. 1 Statistical analyses on ticks and their hosts according to their habitat and migration characteristics were only calculated for the most abundant tick species (I. ricinus and Ha. concinna), due to the fact that the limited numbers of other tick species precluded robust statistical analyses.

Figure 1

Tick-host associations visualized on a plotweb.

Ixodes ricinus (ntotal = 3971, nlarvae = 1229, nnymphs = 2742): Ixodes ricinus subadults occurred most frequently on resident and/or short-distance migrating birds with forest or forest and meadow habitats (Tables 3, 4), This category includes the two species on which the most ticks were found: Blackbirds (nticks = 1073, nbirds = 326), and European Robins (nticks = 924, nbirds = 490) (Table 5). Ixodes ricinus ticks were present on birds year-round, with nymphs reaching their peak in the first half of the sampling periods (1st of March–30th of June), while larvae were the most abundant in the second half (1st of July–31 of October). This was consistent over the course of eight years. The difference between the numbers of nymphs and larvae regarding their half-yearly activity was significant (p 1, Supplementary Fig. 2).

Table 3 Number of ticks according to the typical habitat of their avian hosts.Table 4 Number of ticks according to the migration habit of their avian hosts .Table 5 The five most common avian hosts of Ixodes ricinus (A) and Ha. concinna (B).

Ixodes frontalis (ntotal = 102, nlarvae = 52, nnymphs = 38, nfemale = 12): The European Robin was the most common host of this tick species (nticks = 52, nbirds = 21). The second most frequently identified host species was the Blackbird (nticks = 18, nbirds = 4). Ixodes frontalis occurred most frequently on resident and/or short-distance migrating birds with forest habitat (Tables 3, 4). All stages of I. frontalis were the most abundant in the second half of March every year, during the eight-year-long study period (Supplementary Fig. 3).

Ixodes lividus (ntotal = 13, nfemales = 12, nnymphs = 1): All 13 I. lividus ticks were collected from four Sand Martins (Riparia riparia).

Ixodes festai (ntotal = 8, nfemales = 6, nmales = 2): In total eight ticks of this species were collected. Five ticks were removed from two Blackbirds and three ticks from two Dunnocks (Prunella modularis). It is important to mention, that the two males collected were not feeding, but were in copulation with females.

Ixodes arboricola (ntotal = 1, nnymphs = 1): Only one nymph was collected. It was removed from a Great Tit (Parus major).

Haemaphysalis concinna (ntotal = 1706, nlarvae = 698, nnymphs = 1008): The majority (933 ticks, 54.7%) of individuals of this tick species were found on Savi’s Warbler (Locustella luscinioides) (nbirds = 238), making this bird the most common host of Ha. concinna. This tick species was also frequently collected from Eurasian Reed Warbler (Acrocephalus scirpaceus) (nticks = 157, nbirds = 82). The five most common hosts of Ha. concinna are listed in Table 5. Both Ha. concinna larvae and nymphs were active in the summer. However, the peaks of their abundance showed differences over the study period. In particular, the peak of infestation of birds with Ha. concinna larvae preceded that of its nymphs in 2015 and 2022, but the opposite trend was observed in 2017 and 2018. In other years, the peak larval and nymphal infestations occurred simultaneously (Supplementary Fig. 2).

It was found that the host habitat (reed, forest, meadow, meadow/forest) of I. ricinus and Ha. concinna was significantly different (p 3). We also compared the migratory habits (resident, short-distance migrants, middle-distance migrants, resident or short distance migrants, resident or middle-distance migrants, long-distance migrants) of the hosts of I. ricinus and Ha. concinna. The difference was strongly significant (p 4). According to our findings, Ha. concinna occurred most frequently on long-distance migrant and reed-associated birds, while I. ricinus was the most abundant on short-distance migrants, with forest habitat. (Tables 3, 4).

Haemaphysalis punctata (ntotal = 28, nlarvae = 28): A single Common Quail (Coturnix coturnix) was found with 28 feeding larvae.

Hyalomma marginatum (ntotal = 2, nnymphs = 2): One engorged nymph was collected from European Robin, and another from Song Trush (T. philomelos). Both were collected in the first half of April (in 2015, and 2016, respectively).

Hyalomma rufipes (ntotal = 1, nnymph = 1): Only one engorged nymph was found, which was feeding on a European Pied Flycatcher (Ficedula hypoleuca) in the second half of April 2015.

Dermacentor reticulatus (ntotal = 1, nfemale = 1): One female of this species was found on a Blackbird (Turdus merula), though it had not started to feed.

Host associations of ticks according to bird weight and feeding level characteristics

The mean intensity of infestation with I. ricinus nymphs was the highest among bird species with typical body weight above 100 g, whereas this was the lowest among bird species measuring below 10 g (Supplementary Fig. 4). The same was not true in the case of Ha. concinna nymphs, because the mean intensity of tick-infestation was the highest on birds weighing between 10.1 and 20 g (Supplementary Fig. 4).

When the numbers of I. ricinus, I. frontalis and Ha. concinna  were compared according to the feeding level of their hosts (only ground level or above ground categories were tested), I. ricinus tended to predominate on ground-feeding birds, whereas Ha. concinna nymphs and larvae were more often found on birds looking for food items above the ground level (p I. ricinus and I. frontalis (p = 0.2584) (Table 6).

Table 6 Number of ticks according to the typical feeding place of their avian hosts.

Source link : https://www.nature.com/articles/s41598-024-55021-9

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Publish date : 2024-02-29 08:00:00

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