Seasonal abundance and activity of the hard tick Haemaphysalis longicornis (Acari: Ixodidae) in North China

Seasonal abundance and activity of all the three post-embryogenic stages of Haemaphysalis longicornis, both feeding and free-living phases, were evaluated over a period of 2 years, from February 2008 to January 2010, in North China. Feeding ticks were removed weekly from head and ears of domestic sheep and the attachment sites of this tick were assessed coinstantaneously; free-living ticks were collected weekly in four habitat types by flag-dragging. The results suggested that H. longicornis mainly resides in shrubs and completes one generation per year with population attrition between stages. Infestation of nymphs was detected from March to September with highest peak between late April and early May; adults were detected from April to September with highest peak between late June and July, and an overwintering male population was found during late September to March; infestation of larvae was observed from June to October and peaked between middle August and early September. Most of this tick (91%) attached to head and ears of hosts. Additionally, we captured rodents from April to September 2008, but only a negligible number of nymphs were detected. This result suggested that rodents are not the principal hosts for this tick in the study area.     

Seasonal dynamics of the tick Haemaphysalis tibetensis in the Tibetan Plateau,China

The tick Haemaphysalis tibetensis (Acari: Ixodidae) Hoogstraal is an important arthropod vector widespread in the Qinghai‐Tibet Plateau, and knowledge of its seasonal dynamics is still poor. The current study investigated the seasonal dynamics of the parasitic and non‐parasitic H. tibetensis over a 2‐year period from March 2014 to February 2016 in the Tibetan Plateau, China. During this timeframe, non‐parasitic ticks were collected weekly by flag‐dragging in grassland and shrubland areas, and parasitic ticks were removed weekly from selected sheep. Plateau pikas were captured using traps and examined for immature ticks between May to September 2014. Results suggest that non‐parasitic H. tibetensis were mainly distributed in the grassland, and the parasitic adults and nymphs were found mostly on sheep. Larvae were usually found on Plateau pikas and the prevalence of infestation and mean parasitic intensity were 72.1 and 1.81%, respectively. Adults were observed from March to July with the major peak occurring in mid‐April. Nymphs were found from March to August and reached a peak in late June. Larvae were collected from April to September, and their numbers peaked in late May. In the parasitic and non‐parasitic period, the overall sex ratio of males to females was 1.62 and 1.30, respectively. Results show that H. tibetensis can complete one generation per year, with a population overlap between stages over the spring‐summer months. These findings provide additional information on the biology and ecology of H. tibetensis as well as insights on its control in the environment and on sheep.     

Stage-specific population dynamics of cottony cushion scale,Icerya purchasi (Hemiptera: Monophlebidae), in citrus orchards in Jeju,Korea

The cottony cushion scale, Icerya purchasi Maskell (Hemiptera: Monophlebidae), is a polyphagous, cosmopolitan and destructive pest of citrus. This study was conducted to obtain the stage-specific phenology of I. purchasi for seasonal management strategies in the field. Movement of crawlers (hatched nymphs) in egg sacs of overwintered females started in late May, peaked in early to mid-June, and was completed by late June. Generally, the 1st generation occurred from late May until late September and the overlapping second generation occurred from early September. The 1st nymphs in the 1st generation peaked in mid June. The 2nd nymphs showed peak activity in late July. The 3rd nymphs showed peak population in early September. The 1st generation adults peaked in mid September. In the 2nd generation, the 1st nymphs peaked in early October, the 2nd nymphs showed peak activity in late October, and the 3rd nymphs reached a plateau after mid October. The 2nd generation adults occurred from late October. Consequently, two life cycles were competed in the Jeju area. The average fertilities of I. purchasi were 623 and 247 crawlers per female in overwintered and summer generations, respectively. An average of 20.7% of all citrus orchards was infested with I. purchasi, with a mean of 3.9% infested trees in Jeju. These results should be useful in establishing management strategies for I. purchasi in citrus orchards.     

Host utilization and seasonal occurrence of Dermacentor

A total of 3,235 Dermacentor variabilis (Say) specimens were collected from birds, mammals, and by dragging vegetation, and 2,683 D. albipictus (Packard) ticks were collected from deer from 1993 to 1996. Peak seasonal occurrence of adult D. variabilis was from May through July with a precipitous decrease in August. Nymphal D. variabilis populations peaked in June. Peak activity of larvae was bimodal, with one activity peak during late summer (September) and a second peak in winter or early spring. The raccoon, Procyon lotor (L.), was the principal host of adults followed by the Virginia opossum, Didelphis virginiana Kerr. Rodents and the eastern cottontail rabbit, Sylvilagus floridanus (J. A. Allen), were the primary hosts of nymphs. The marsh rice rat, Oryzomys palustris (Harlan), was the principal host of larvae followed by the pine vole, Microtus pinetorum (Le Conte), and white-footed mouse, Peromyscus leucopus (Rafinesque). All stages of D. albipictus were found only on white-tailed deer, Odocoileus virginianus (Zimmermann). Numbers of adult and nymphal D. albipictus peaked in November, whereas larvae peaked in September.     

森林革蜱、草原革蜱感染和经期传播莱姆病螺旋体的实验研究

以实验室培育的非感染森林革蜱Dermacentor silvarum、草原革蜱D. nuttalli刺叮人工感染21天后的阳性KM鼠,利用分离培养和PCR方法检测蜱对螺旋体的保持能力以及体内螺旋体对敏感动物的感染能力。结果如下：非感染幼蜱均可以通过吸血获得莱姆病螺旋体,饱血森林革蜱和草原革蜱幼蜱PCR阳性率均为50.0%而分离阳性率都为20.0%。饱血脱落后,这些幼蜱只能在饱血后2天内分离到莱姆病螺旋体。PCR检测阳性也只能持续到4天,均不能跨越蜕皮阶段。蜕化为若蜱后,若蜱以及分别受到这些若蜱刺叮的KM鼠均未发现阳性感染。非感染若蜱吸食感染的KM鼠后,饱血森林革蜱和草原革蜱获得了莱姆病螺旋体,PCR检测阳性率分别为50.0%和20.0%。分离阳性率分别达到33.3%和60.0%。这些若蜱分别于饱血后2天和3天可以分离到莱姆病螺旋体,PCR扩增阳性也只能分别持续到饱血后4天和6天,均不能跨越蜕皮阶段;蜕化为成蜱后,成蜱以及受到它们攻击的KM鼠均未获阳性检测结果。同种蜱不同地理株在感染和保持莱姆病螺旋体的能力上也没有差异。森林革蜱、草原革蜱的幼蜱和若蜱虽可以吸血感染但均不具备经期传播莱姆病螺旋体Borrelia garinii CHNM4的能力,作为莱姆病媒介的可能性不大。     

The effects of sampling method and vegetation type on the estimated abundance of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> ticks in forests

Estimating the spatial and temporal variation in tick abundance is of great economical and ecological importance. Entire-blanket dragging is the most widely used method to sample free-living ixodid ticks. However, this technique is not equally efficient in different vegetation types. The height and structure of the vegetation under study will not only determine the likelihood of a tick-blanket contact, but will also determine the rate of dislodgement. The purpose of this study was therefore to determine whether the alternative strip-blanket is more effectively in picking up ticks than the standard entire-blanket. Sampling was carried out in four forest understory vegetation types that differed in height and structure on five collection dates between April and September 2008. A total of 8,068 Ixodes ricinus ticks was collected (778 adults, 1,920 nymphs, and 5,370 larvae). The highest numbers of ticks were collected along the forest trails, where the dominant vegetation consisted of short grasses. The lowest numbers of ticks were collected in bracken-fern-dominated sites, where the vegetation seriously hampered tick sampling. Surprisingly, in each vegetation type, significantly more nymphs and adults were collected using the entire-blanket. However, the strip-blanket was more effectively in collecting larvae, especially in dense and tall vegetation.     

Infestation and seasonal activity of Ixodes vespertilionis Koch, 1844 (Acari: Ixodidae) on the Maghreb mouse‐eared bat,Myotis punicus Felten, 1977, in northeastern Algeria

Infestation of Ixodes vespertilionis Koch, 1844 on Myotis punicus Felten, 1977 from two sites (Trios Tunnel and Sidi Trad cave) in northeastern Algeria was studied. An overall infestation of 41.4% for all stages was found among bats collected from both sites. By stage, a total of eight females, 70 nymphs, and 107 larvae were recovered from both populations. The number of females recovered per bat at Sidi Trad ranged from 0‐1, for nymphs 0‐2, and for larvae 0‐2. While no female ticks were collected at Trios Tunnel, the number of nymphs ranged from 0‐2 and for larvae 0‐2. At Trios Tunnel, the number of nymphs was significantly higher during April and June but not for July and September. On the other hand, the number of larvae increased from July to November, while at Sidi Trad cave, female ticks were recovered during April and May and then disappeared until the end of the study period. Significant differences were noted during all the months when compared with all stages. Nymphs infested bats significantly during April and May, declined in June and July, and then became steady until October. Larvae peaked in July, with low frequency in April, and then fluctuated from August to November.     

Seasonal and geographical distribution of adult Ixodes scapularis say (Acari: Ixodidae) in Louisiana.

The distribution and seasonality of adult black-legged ticks (Ixodes scapularis Say) in Louisiana was measured. The presence of adult ticks was determined by flagging at 106 sites throughout Louisiana. It was concluded that Ixodes scapularis is widely distributed throughout Louisiana. Ticks were also collected twice per month at one site over a 15-month period by flagging and use of CO2 traps to establish the relative seasonal abundance pattern of free-living adult ticks. Host-seeking, black-legged adult ticks were collected from October to May. Peak adult abundance was observed in December. More ticks were collected by the use of CO2 traps compared to flagging in October, November, and February. No black-legged tick larvae or nymphs were collected in this study using either collection method.     

中国东北地区大豆主要食叶性害虫种类分析

2005～2007年,对大豆食叶性害虫种类开展了系统调查。共发现5目、15科、29种害虫。大豆蚜Aphisglycines Matsumura、茄无网长管蚜Acythosiphon solani(Kaltenbach)、豆黄蓟马Thrips nigropilosus Uzel、二条叶甲成虫Monolepta nigrobilineata(Motsch.)、双斑萤叶甲成虫Monolepta hieroglyphica(Motsch.)、大造桥虫Ascotis selenaria Schiffermüller et Denis幼虫及豆卜馍夜蛾Bomolocha tristalis Lederer幼虫为主要食叶性害虫。其中,大豆蚜、茄无网长管蚜田间发生较早,6月上旬已有发生;大造桥虫幼虫、豆卜馍夜蛾幼虫发生较晚,6月下旬后田间始见发生。豆黄蓟马成虫危害期为6月上旬至9月上旬,若虫危害期为6月中旬至8月下旬。二条叶甲成虫的危害期为6月上旬至9月下旬,双斑萤叶甲成虫发生期为7月上旬至9月上旬。     

Seasonal Development and Population Fluctuations of Arrowhead Scale,Unaspis yanonensis (Homoptera: Diaspididae), in Citrus orchards in Jeju,Korea

Arrowhead scale, Unaspis yanonensis (Kuwana), feeds on the foliage, stems, and fruits of citrus trees, and causes tree dieback when heavy infestations occur. The objective of this study was to collect basic data to establish seasonal management strategies for U. yanonensis. The abundances of male nymphs and female adults were monitored in unsprayed citrus orchards. The overwintered females started to produce their progenies (1st gen.) from mid-May. The populations of the 1st nymphs in the 1st generation showed a bimodal occurrence pattern, with a 1st larger peak between late May and early June, and a 2nd smaller peak in June. The nymphs in the 2nd generation, which were laid from newly developed females, were observed from late July, and the 1st peak occurred in mid-August, followed by an obscure later peak (the 2nd peak) around late September. The numbers of live females for the overwintered populations began to decrease gradually from early June by the impact of the predacious Chilocorus kuwanae, as well as by natural mortality factors, and dropped to a low level in mid-July. When there were abundant predator attacks, the U. yanonensis female populations sharply decreased from early June and were almost nonexistent in July. New female adults (1st generation adults) appeared from late June and peaked in mid-July. The 2nd generation female adults, consequently, the overwintering generation, occurred from mid- September, and gradually increased to late October. Overall, these results will be useful in terms of management strategies for U. yanonensis in citrus orchards.     

Abundance and seasonal activity of questing Ixodes ricinus ticks in their natural habitats in southern Germany in 2011

Questing ticks were sampled monthly over a period of 11 months from February, 2011 to December, 2011 at 13 sites in southern Germany using the flagging method. The ticks were identified to species, gender, and stadium. Although both I. ricinus and D. reticulatus were sampled, this study concentrated on I. ricinus, since it was the most abundant tick to be found. Additional weather data (air and soil temperature, relative air humidity, precipitation, sunshine duration) were recorded on each sampling site and the local vegetation described. A total of 14, 394 ticks was collected (7,862 larvae, 5,568 nymphs, 964 adults) and their activity was recorded in order to determine the seasonal activity pattern over different periods of the year. In contrast to the widely accepted pattern of a bimodal seasonal activity in moderate areas with a dominant peak in spring and a minor peak in autumn, a unimodal activity pattern was found for all development stages on six of the 12 sampling sites. Tick abundance was compared to weather variables. Tick host‐seeking activity was found to be significantly dependent on the temperature at ground level, precipitation, and sunshine duration as well as relative air humidity. Adult ticks showed a positive correlation with the duration of sunshine, whereas nymphs were mostly unaffected by this phenomenon.     

Tick burden on European roe deer (<Emphasis Type="Italic">Capreolus capreolus</Emphasis>)

In our study we assessed the tick burden on roe deer (Capreolus capreolus L.) in relation to age, physical condition, sex, deer density and season. The main objective was to find predictive parameters for tick burden. In September 2007, May, July, and September 2008, and in May and July 2009 we collected ticks on 142 culled roe deer from nine forest departments in Southern Hesse, Germany. To correlate tick burden and deer density we estimated deer density using line transect sampling that accounts for different detectability in March 2008 and 2009, respectively. We collected more than 8,600 ticks from roe deer heads and necks, 92.6% of which were Ixodes spp., 7.4% Dermacentor spp. Among Ixodes, 3.3% were larvae, 50.5% nymphs, 34.8% females and 11.4% males, with significant seasonal deviation. Total tick infestation was high, with considerable individual variation (from 0 to 270 ticks/deer). Adult tick burden was positively correlated with roe deer body indices (body mass, age, hind foot length). Significantly more nymphs were found on deer from forest departments with high roe deer density indices, indicating a positive correlation with deer abundance. Overall, tick burden was highly variable. Seasonality and large scale spatial characteristics appeared to be the most important factors affecting tick burden on roe deer.     

Seasonal dynamics of the brown dog tick,Rhipicephalus sanguineus,on a confined dog population in Italy

This study evaluated the seasonal dynamics of Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) on naturally infested dogs in a private shelter in southern Italy. From March to May 2008, 39 autochthonous mixed‐breed young dogs and 10 beagles were enrolled in the study. From March 2008 until March 2009, every 21 ± 2 days, 11 body sites of each dog were checked for ticks. At each follow‐up, the number of ticks, their developmental stage, sex and location on the dog's body were recorded. Adult ticks were found throughout the year, but immatures were absent in January and February. The adult tick population increased from July to August, whereas the load of immatures increased in early July and peaked in September, which suggests that R. sanguineus develops one generation per year in this area. The mean number of immature ticks per infested dog was higher than that of adults from March to October 2008. Ears, interdigital areas and armpits were the most frequent attachment sites of adult ticks. At the last follow‐up, a total of 2266 ticks were collected and identified as R. sanguineus. The results suggest that R. sanguineus develops one generation per year in the study area, but that it infests dogs in all seasons. This information should be taken into account when planning control programmes against this tick species and the pathogens it transmits.     

Study of the life cycle of Amblyomma dubitatum (Acari: Ixodidae) based on field and laboratory data

The life cycle of Amblyomma dubitatum was described based on the seasonal distribution of all parasitic stages and the development periods of engorged ticks under different conditions of photoperiod and temperature. All stages were found active along the entire year in the study area. Larvae peaked from May to July, nymphs peaked from July to October, and females peaked from November to March. This pattern represents a life cycle with one generation per year with most of the ticks reaching adulthood during the warmest months. The analysis of the effect of the photoperiod on the development of A. dubitatum showed no indication of morphogenetic diapause. Exposure of ticks to field conditions indicates a delay in metamorphosis of immature stages, in the oviposition of females and in the incubation of eggs, which were associated with low winter temperatures. The results indicate that though A. dubitatum has a one year life cycle, more than one cohort can co-exist within the same population in a certain interval of time. Finally, the potential role of small rodents as hosts for larvae and nymphs of A. dubitatum is confirmed.     

Drop off rhythm and survival periods of <Emphasis Type="Italic">Amblyomma lepidum</Emphasis> (Acari: Ixodidae) under field conditions

In this study, engorged Amblyomma lepidum ticks were found to drop off in two peaks, one in the morning and one in the evening. Most larvae and females engorged during the morning hours between 06.00 h and 10.00 h with a peak around 08.00 h, whereas the majority of the nymphs dropped in the evening between 18.00 h and 24.00 h with the peak around 22.00 h. Although the effect of time on drop-off patterns of the ticks was statistically significant (p≤ 0.001), there were no significant seasonal influences. Survival of unfed stages of A. lepidum was also studied and was found to increase from larvae to adult ticks. The longest survival periods of 10, 11 and 14 weeks were recorded during the wet season for larvae, nymphs and adults, respectively. It is concluded that environmental conditions required for survival of A. lepidum are optimal only during the wet season and that during other seasons the tick depends primarily on prevailing micro-climatic conditions for its survival.     

Ticks on reptiles and amphibians in Central Amazonia,with notes on rickettsial infections

Reptiles and amphibians are exceptional hosts for different ectoparasites, including mites and ticks. In this study, we investigated tick infestations on reptiles and amphibians trapped in Central Amazonia, and also assessed the presence of rickettsial infections in the collected ticks. From September 2016 to September 2019, 385 reptiles (350 lizards, 20 snakes, 12 tortoises, and three caimans) and 120 amphibians (119 anurans and one caecilian) were captured and examined for ectoparasites. Overall, 35 (10%) lizards, three (25%) tortoises and one (0.8%) toad were parasitized by ticks (124 larvae, 32 nymphs, and 22 adults). In lizards, tick infestation varied significantly according to landscape category and age group. Based on combined morphological and molecular analyses, these ticks were identified as Amblyomma humerale (14 larvae, 12 nymphs, 19 males, and one female), Amblyomma nodosum (three larvae, one nymph, and one female), and Amblyomma rotundatum (four larvae, three nymphs, and one female), and Amblyomma spp. (103 larvae and 16 nymphs). Our study presents the first records of A. nodosum in the Amazonas state and suggests that teiid lizards are important hosts for larvae and nymphs of A. humerale in Central Amazonia. Moreover, a nymph of A. humerale collected from a common tegu (Tupinambis teguixin) was found positive for Rickettsia amblyommatis, which agrees with previous reports, suggesting that the A. humerale-R. amblyommatis relationship may be more common than currently recognized.

     

Ticks infesting domestic animals in Italy: current acarological studies carried out in Sardinia and Basilicata regions

The note reviews published and unpublished data on acaralogical studies carried out by different parasitologists' groups in Sardinia and Basilicata regions. In Sardinia 72 collecting sites were investigated and a total of 4,086 ticks were collected from hosts (cattle, sheep, goats and pigs) and from soil. So far 2,413 ticks belonging to six genera have been identified: Rhipicephalus (67.2%), Haemaphysalis (24.1%), Hyalomma (2.7%), Boophilus (0.7%), Dermacentor (4.9%), Ixodes (0.3%). Host-associated ticks were collected from 50 out of 200 selected farms in Basilicata. About 4,000 tick specimens were collected and 1,794 ticks have been identified (of which 1,215 were adults, 6 larvae and 573 nymphs). The following genera were identified: Ixodes (20%), Rhipicephalus (27%), Hyalomma (31%), Haemaphysalis (18%), Dermacentor (6%). The seasonal distribution of the species identified in the two regions studies is discussed from a geographical and climatic point of view.     

Seasonal abundance and reproductive season of <Emphasis Type="Italic">Chauliops fallax</Emphasis> (Heteroptera: Malcidae) on kudzu <Emphasis Type="Italic">Pueraria lobata</Emphasis>

We investigated the seasonal abundance and seasonal dynamics of reproduction in the stalk-eyed bug Chauliops fallax Scott, which is described as a minor pest of bean plants such as soybean and a minor cause of pecky rice. We counted the number of adult males and females, mating pairs, and nymphs of C. fallax on kudzu plants, Pueraria lobata (Willd.), in the southern part of Okayama City, Japan, from 2005 to 2007 and in 2009. Two peaks in abundance for mating pairs were found in late May and August. Both male and female solitary adults appeared from late April, and two peaks of solitary adults were found in May and September. Two clearly separate peaks of nymphs were found in late June and late August. Therefore, it seems that C. fallax produces two generations a year in the southern Okayama area. These data may provide essential information for pest control, and therefore, we discuss them from an applied entomological standpoint to predict invasions by C. fallax into agriculture fields from weeds that grow around and/or in fields.     

Seasonal dynamics of the Cayenne tick, Amblyomma cajennense on horses in Brazil

The population dynamics of all stages of the Cayenne tick, Amblyomma cajennense (Fabricius) (Acari: Ixodidae) on horses was evaluated over a period of 2 years in the district of Pedro Leopoldo, State of Minas Gerais, Brazil. Every 14 days, the left side of 20 horses was brushed for collection of immature stages; counts of adults were also undertaken. Infestation by larvae was detected from April to August, whereas nymphs were observed from June to October. Infestation by adults was detected throughout the year, and the highest population density occurred from September to March. The number of males was always higher than the number of females, but with considerable reduction in the male : female ratio between April and July. It was observed that 25% of the horses carried 41% of the infesting ticks, and 20% carried only 10% of the ticks during the entire period of the study.