Development and biological characteristics of <Emphasis Type="Italic">Haemaphysalis longicornis</Emphasis> (Acari: Ixodidae) under field conditions

The development and biological characteristics of Haemaphysalis longicornis were investigated under field conditions in Xiaowutai National Natural Reserve Area, North China. Unfed larvae, nymphs and adults were fed on rabbits and exposed to daylight. Three free-living stages were allowed to develop in field plot selected in a tick natural habitat. The host seeking behavior and seasonal occurrence were observed. Haemaphysalis longicornis were active from mid March to mid October. The premoult period of nymphs and preoviposition of females were regulating phases of their life cycle. The developmental durations of eggs, larvae and adults were constant under field conditions regardless when the development started. The oviposition periods in May and June were statistically shorter than those in July and August. The daily oviposition patterns of females engorged in May and June demonstrated unobvious peak, which differed from those engorged in July and August. The daily oviposition peak of the latter occurred on the 4th day of oviposition. Moreover, a positive correlation was found between the mass of the laid egg and the body weight of engorged females (r = 0.62, P < 0.001). The female reproductive efficiency indices were 2.9, 6.1, 10.5 and 9.0 in May, June, July and August, respectively. The mean weight (3.33 mg) of engorged nymphs molting to females was significantly higher than that (2.35 mg) of those molting to males (P < 0.001), but the body weights of both sexes were overlapping.     

Abundance estimation of <Emphasis Type="Italic">Ixodes</Emphasis> ticks (Acari: Ixodidae) on roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis>)

Despite the importance of roe deer as a host for Ixodes ticks in central Europe, estimates of total tick burden on roe deer are not available to date. We aimed at providing (1) estimates of life stage and sex specific (larvae, nymphs, males and females, hereafter referred to as tick life stages) total Ixodes burden and (2) equations which can be used to predict the total life stage burden by counting the life stage on a selected body area. Within a period of 1½ years, we conducted whole body counts of ticks from 80 hunter-killed roe deer originating from a beech dominated forest area in central Germany. Averaged over the entire study period (winter 2007–summer 2009), the mean tick burden per roe deer was 64.5 (SE ± 10.6). Nymphs were the most numerous tick life stage per roe deer (23.9 ± 3.2), followed by females (21.4 ± 3.5), larvae (10.8 ± 4.2) and males (8.4 ± 1.5). The individual tick burden was highly aggregated (k = 0.46); levels of aggregation were highest in larvae (k = 0.08), followed by males (k = 0.40), females (k = 0.49) and nymphs (k = 0.71). To predict total life stage specific burdens based on counts on selected body parts, we provide linear equations. For estimating larvae abundance on the entire roe deer, counts can be restricted to the front legs. Tick counts restricted to the head are sufficient to estimate total nymph burden and counts on the neck are appropriate for estimating adult ticks (females and males). In order to estimate the combined tick burden, tick counts on the head can be used for extrapolation. The presented linear models are highly significant and explain 84.1, 77.3, 90.5, 91.3, and 65.3% (adjusted R ²) of the observed variance, respectively. Thus, these models offer a robust basis for rapid tick abundance assessment. This can be useful for studies aiming at estimating effects of abiotic and biotic factors on tick abundance, modelling tick population dynamics, modelling tick-borne pathogen transmission dynamics or assessing the efficacy of acaricides.     

The first record of <Emphasis Type="Italic">Haemaphysalis kopetdaghica</Emphasis> and the second record of <Emphasis Type="Italic">Hyalomma kumari</Emphasis> (Acari,Ixodidae) in Tajikistan

Five males and one female of Haemaphysalis kopetdaghica Kerbabaev, 1962 and four males and five females of Hyalomma kumari Sharif, 1928 were collected from sheep in the Darvaz Region of Tajikistan at the Afghanistan frontier in March 14, 2006. In Tajikistan, H. kopetdaghica were found for the first time and H. kumari, for the second time.     

Physiological effects upon <Emphasis Type="Italic">Amblyomma americanum</Emphasis> (Acari: Ixodidae) infected with <Emphasis Type="Italic">Beauveria bassiana</Emphasis> (Ascomycota: Hypocreales)

Unfed adult Amblyomma americanum were exposed to the entomopathogenic fungus Beauveria bassiana. Ticks exposed to the fungus exhibited reduced survival and increased water loss as indicated by change in weight. Treated ticks survived 7.2 ± 0.22 days (mean ± SE) and controls survived 17.9 ± 0.73 days (P = 0.01; df = 57). At death, ticks exposed to the fungus had lost 25.2 ± 0.84% of their starting weight; control ticks had lost 14.1 ± 0.85% of their starting weight (P = 0.01; df = 96). Water loss was highest immediately following inoculation, although losses continued to be higher than in uninoculated ticks. This suggests that fungal penetration causes sufficient cuticle damage to cause desiccation, although other water-loss avenues exist, including increased time of spiracular opening. Additionally this study did not eliminate the possibility of a negative impact on water vapor uptake. This is the first study to investigate the effect of an entomopathogenic fungus on the water balance of a tick.     

Pathogenicity of <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> (Deuteromycetes) and permethrin to <Emphasis Type="Italic">Ixodes scapularis</Emphasis> (Acari: Ixodidae) nymphs

Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC₅₀ of 10⁷ spores/ml and induced 70% mortality at 10⁹ spores/ml. In a field study, however, 10⁹ spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.     

In vitro efficacy of <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> sensu lato against unfed <Emphasis Type="Italic">Amblyomma parvum</Emphasis> (Acari: Ixodidae)

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum.     

Detection of a questing <Emphasis Type="Italic">Hyalomma marginatum</Emphasis><Emphasis Type="Italic">marginatum</Emphasis> adult female (Acari,Ixodidae) in southern Germany

The first finding of a questing Hyalomma marginatum marginatum female tick in Germany is described. The tick was found in May 2006 on the clothing of a person who had spent the preceding day in rural surroundings in southern Germany. As the infested person had also been visiting Spain where H. m. marginatum is known to occur some weeks prior to finding the tick, it is not clear whether the tick had been imported by him as a female or by another host in a preimaginal stage and succeeded to develop to an adult in Germany. H. m. marginatum is a thermophilic tick species usually occurring in relatively dry and warm regions of southern Europe, northern Africa and some parts of Asia. It is a vector of several disease agents of human relevance including Crimean-Congo hemorrhagic fever virus. Although, by PCR examination, the female was found neither infected with this virus nor with Rickettsia aeschlimannii, another human pathogen which has been found in Spanish Hyalomma ticks, its mere finding should be taken seriously and draw further attention to the increasing problem of the import and spread of putatively tropical vectors of disease to central Europe.     

Acaricidal effects of <Emphasis Type="Italic">Corymbia citriodora</Emphasis> oil containing <Emphasis Type="Italic">para</Emphasis>-menthane-3,8-diol against nymphs of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> (Acari: Ixodidae)

The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A–E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results obtained by methods A, C and E, the LC₅₀ range was 0.035–0.037 mg PMD/cm² and the LC₉₅ range was 0.095–0.097 mg PMD/cm² at 4 h of exposure; the LT₅₀ range was 2.1–2.8 h and the LT₉₅ range was 3.9–4.2 h at 0.1 mg PMD/cm². To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm²) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic to nymphs of I. ricinus and may be useful for tick control.     

Biology and life cycle of <Emphasis Type="Italic">Amblyomma incisum</Emphasis> (Acari: Ixodidae)

Amblyomma incisum Neumann is a major tick species in the Atlantic Forest of Brazil. Tapir is the main host for adult ticks and a high aggressiveness of nymphs to humans has been reported. In this work data on the biology and life cycle of this tick species is presented for the first time. It was shown that horse is a suitable host for A. incisum adults and rabbit for larvae and nymphs. It was also shown that A. incisum is a big tick species (mean engorged female weight of 1.96 g) with a long life cycle which lasts 262.3 days when maintained at 27°C and 85% RH. These laboratory conditions were, however, inappropriate and egg hatching rate (1.2%) was very low. Nevertheless egg hatching of ticks in a forest patch increased considerably (72.2%) indicating that this A. incisum population is highly dependent on a forest-like environment.     

Biology of <Emphasis Type="Italic">Dermacentor silvarum</Emphasis> (Acari: Ixodidae) under laboratory conditions

The minimum life cycle of Dermacentor silvarum Olenev had a mean duration of 87.5 days (range 74–102 days) under laboratory conditions [(27±1 °C), 70% RH, 6 L: 18 D]. The mean time in (days) for the different stages of its cycle was as follows: incubation period of eggs was 15.3 days; prefeeding, feeding and premoulting periods of larvae and nymphs averaged 5.5, 4.0 and 7.3 days, and 5.2, 5.0 and 14.6 days, respectively; prefeeding, feeding, preoviposition and oviposition periods of female adults lasted for 7.8, 4.5, 4.3 and 14.0 days, respectively. There existed a highly significant correlation between engorged body weight of females and egg masses laid (r = 0.9877, p<0.001). The reproductive efficiency index (REI) and reproductive fitness index (RFI) in females were 11.09 and 9.58, respectively. No relationship between nymphal engorged body weight and resultant sexes was observed. Delayed feeding and non-oviposition (in June and July) existed in females, and low temperature (−10 °C) treatment for 45 days could terminate oviposition diapause. However, the egg masses laid by post-diapause females were significantly smaller than those laid by females engorged in March, April and May.     

The life cycle of <Emphasis Type="Italic">Amblyomma auricularium</Emphasis> (Acari: Ixodidae) using rabbits (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) as experimental host

The life cycle of Amblyomma auricularium (Conil) is reported for the first time, using rabbits as experimental host. Developmental periods of free-living stages were observed in an incubator at 27 ± 1°C, 80 ± 10% RH and 24 h darkness. The complete life cycle, including pre-feeding periods for each parasitic stage, ranged from 97 to 162 days. The overall sex ratio was 1.16:1 (M:F). Feeding and premolt periods, molting success, and engorgement weight of nymphs were statistically different between males and females (P < 0.01), but because their ranges overlapped, they cannot be used to predict the sex with accuracy. The potential role of rabbits as experimental hosts for rearing A. auricularium in the laboratory is discussed.     

<Emphasis Type="Italic">Ty</Emphasis>1<Emphasis Type="Italic">/copia</Emphasis>- and <Emphasis Type="Italic">Ty</Emphasis>3<Emphasis Type="Italic">/gypsy</Emphasis>-like DNA sequences in <Emphasis Type="Italic">Helianthus </Emphasis>species

Two repeated DNA sequences isolated from a partial genomic DNA library of Helianthus annuus, p HaS13 and p HaS211, were shown to represent portions of the int gene of a Ty3 /gypsy retroelement and of the RNase-Hgene of a Ty1 /copia retroelement, respectively. Southern blotting patterns obtained by hybridizing the two probes to BglII- or DraI-digested genomic DNA from different Helianthus species showed p HaS13 and p HaS211 were parts of dispersed repeats at least 8 and 7 kb in length, respectively, that were conserved in all species studied. Comparable hybridization patterns were obtained in all species with p HaS13. By contrast, the patterns obtained by hybridizing p HaS211 clearly differentiated annual species from perennials. The frequencies of p HaS13- and p HaS211-related sequences in different species were 4.3x10(4)-1.3x10(5) copies and 9.9x10(2)-8.1x10(3) copies per picogram of DNA, respectively. The frequency of p HaS13-related sequences varied widely within annual species, while no significant difference was observed among perennial species. Conversely, the frequency variation of p HaS211-related sequences was as large within annual species as within perennials. Sequences of both families were found to be dispersed along the length of all chromosomes in all species studied. However, Ty3 /gypsy-like sequences were localized preferentially at the centromeric regions, whereas Ty1/ copia-like sequences were less represented or absent around the centromeres and plentiful at the chromosome ends. These findings suggest that the two sequence families played a role in Helianthusgenome evolution and species divergence, evolved independently in the same genomic backgrounds and in annual or perennial species, and acquired different possible functions in the host genomes.     

Genetic diversity of <Emphasis Type="Italic">avenin-like b</Emphasis> genes in <Emphasis Type="Italic">Aegilops tauschii</Emphasis> Coss

Avenin-like storage proteins influence the rheological properties and processing quality in common wheat, and the discovery of new alleles will benefit wheat quality improvement. In this study, 13 avenin-like b alleles (TaALPb7D-A–M) were discovered in 108 Aegilops tauschii Coss. accessions. Ten alleles were reported for the first time, while the remaining three alleles were the same as alleles in other species. A total of 15 nucleotide changes were detected in the 13 alleles, resulting in only 11 amino acid changes because of synonymous mutations. Alleles TaALPb7D-E, TaALPb7D-G, and TaALPb7D-J encoded the same protein. These polymorphic sites existed in the N-terminus, Repetitive region (Left), Repetitive region (Right) and C-terminus domains, with no polymorphisms in the signal peptide sequence nor in those encoding the 18 conserved cysteine residues. Phylogenetic analysis divided the TaALPb7Ds into four clades. The Ae. tauschii alleles were distributed in all four clades, while the alleles derived from common wheat, TaALPb7D-G and TaALPb7D-C, belonged to clade III and IV, respectively. Alleles TaALPb7D-G and TaALPb7D-C were the most widely distributed, being present in nine and six countries, respectively. Iran and Turkey exhibited the highest genetic diversity with respect to TaALPb7D alleles, accessions from these countries carrying seven and six alleles, respectively, which implied that these countries were the centers of origin of the avenin-like b gene. The new alleles discovered and the phylogenetic analysis of avenin-like b genes will provide breeding materials and a theoretical basis for wheat quality improvement.     

<Emphasis Type="Italic">Beauveria bassiana</Emphasis> (Ascomycota: Hypocreales) as a management agent for free-living <Emphasis Type="Italic">Amblyomma americanum</Emphasis> (Acari: Ixodidae) in Ohio

Unfed adult Amblyomma americanum were exposed to the entomopathogenic fungus Beauveria bassiana and placed in the field. Ticks exposed to the fungus experienced higher mortality than those in the control group (P = 0.001). It is recommended that for inclusion in a tick management program, the fungus be applied in the late evening during the months March through June as this is when ticks are most active and conditions suitable for fungal activity occur.     

New combinations and typifications in <Emphasis Type="Italic">Bistorta</Emphasis>, <Emphasis Type="Italic">Persicaria</Emphasis>, <Emphasis Type="Italic">Polygonum,</Emphasis> and <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae)

New combinations are proposed in anticipation of the Polygonaceae treatment in the forthcoming volume of Intermountain Flora: Polygonum kelloggii var. esotericum, P. kelloggii var. watsonii , Rumex densiflorus var. pycnanthus , R. salicifolius var. utahensis, and R. occidentalis var. tomentellus. Typifications are proposed to facilitate ongoing studies in Polygonaceae and to maintain current usage.     

Uncommon zoogeographical connections in the subgenus <Emphasis Type="Italic">Exopalpiger</Emphasis> Schultze of the genus <Emphasis Type="Italic">Ixodes</Emphasis> Latreille (Acari,Ixodidae)

The species composition of the subgenus Exopalpiger Schulze, 1935 (genus Ixodes Latreille, 1795) and species ranges are considered. Altitude and biotopic preferences and host-parasite relations of species are analyzed. A hypothesis explaining the palaeogenesis of the disjunctive distribution (Europe; South Africa; north and east of South America; New Guinea, southern Australia, New Zealand, and Tasmania) of the subgenus Exopalpiger is proposed.     

Host-parasite association between <Emphasis Type="Italic">Didelphis albiventris</Emphasis> (Didelphimorphia: Didelphidae) and <Emphasis Type="Italic">Ixodes loricatus</Emphasis> (Acari: Ixodidae) in their southern ranges

The parasitism of Ixodes loricatus Neumann on white-eared opposum, Didelphis albiventris Lund, was analysed in the southern ranges of both. In central Argentina, 118 wild opossums were captured from 2005 to 2012. Adults of I. loricatus were collected (prevalence?=?66.1%, mean?=?7.03, median?=?4), but no immature stage. Tick infestation was not affected by sex (p?=?0.27) or age (p?=?0.37) of hosts. In line with previous studies about seasonality of larvae and nymphs of I. loricatus, adult tick infestation showed no seasonal trend. This lack of seasonal pattern of infestation for all parasitic stages of I. loricatus may indicate a life cycle governed by nidicolous behaviour, in such a way that this habit would contribute to minimize the influence of external environmental variables. The tick sex ratio was female biased, with two females per one male (p?=?0.002). The absence of I. loricatus immatures on D. albiventris suggests that in the study region there is clear segregation of immatures in rodents and adults in marsupials.     

Host range and geographical distribution of <Emphasis Type="Italic">Ixodes sigelos</Emphasis> (Acari: Ixodidae)

Larvae, nymphs and females of Ixodes sigelos Keirans, Clifford and Corwin (Ixodidae) were collected in 13 localities of the Patagonian region of Argentina parasitizing eight species of sigmodontine rodents. We report for the first time adults of I. sigelos for Argentina. Besides, we extend the southern limit of its geographical distribution, and six species of sigmodontines are added as new host species of I. sigelos (Phyllotis xanthopygus, Euneomys chinchilloides, Calomys musculinus, Reithrodon auritus, Loxodontomys micropus and Eligmodontia morgani). The presence of larvae, nymphs and females on sigmodontines, as well as more than 50% of the individuals engorged, indicate that I. sigelos can develop the complete parasitic phase of its life cycle on these small mammals. The geographical distribution of I. sigelos is restricted to the biogeographical Andean Region in Argentina and Chile.     

Pedogamy in <Emphasis Type="Italic">Neidium</Emphasis> (<Emphasis Type="Italic">Bacillariophyceae</Emphasis>)

Single (unpaired) vegetative cells of freshwater pennate diatom Neidium cf. ampliatum differentiated into gametangia and produced a single zygote (auxospore) via a pedogamic process. The gametic nuclei fused after auxospore expansion had begun. The auxospore expanded in parallel to the apical axis of the gametangium.