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.     

内蒙古荒漠草原亚洲小车蝗的种群动态

2010—2011年于内蒙古乌兰察布市四子王旗格根塔拉草原对亚洲小车蝗Oedaleus asiaticus(B.-Bienko)种群动态进行了研究。结果表明,亚洲小车蝗种群空间格局为随机分布;亚洲小车蝗于6月中旬开始孵化出土,1～3龄蝗蝻高峰期在6月中下旬至7月初,终见期在7月下旬;4～5龄蝗蝻于6月下旬始见,高峰期在7月上中旬,终见期在7月末;成虫于7月上旬始见,高峰期在7月中旬至8月下旬,终见期在9月上旬。应用最优分割法将亚洲小车蝗种群动态划分为3个阶段:(1)6月中旬,为蝗蝻开始出土期,数量稀少,空间格局为聚集分布或随机分布;(2)6月下旬至7月上中旬,为蝗蝻发生盛期,密度低时为随机分布,密度高时为聚集分布;(3)7月中下旬至9月上旬,为成虫发生期,空间格局为随机分布。     

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.     

金绿宽盾蝽的生物学特性

金绿宽盾蝽Poecilocoris lewisi Distant在北京1年1代,以5龄若虫在侧柏(Platycladus orientalis Franco)附近的落叶和石块下越冬,翌年4月上中旬陆续从越冬处爬出,取食侧柏嫩叶。5月中旬5龄若虫开始羽化,6月初为羽化高峰期,6月中下旬羽化期结束,5月到8月为成虫期,7月底到8月中旬交配产卵,8、9月份若虫由1龄发育至5龄,9月中下旬为5龄若虫高峰期,11月5龄若虫开始转移越冬。     

Assessment of trap plants to regulate numbers of the European tarnished plant bug, Lygus rugulipennis, on late-season strawberries

Various species of plants in the family Asteraceae were shown to be hosts for the European tarnished plant bug Lygus rugulipennis and one, Matricaria recutita, was chosen as a potential trap plant for adults of this capsid species on their migration into fields of late-season strawberries from other host plants in July. There was a delay in the build-up of populations of nymphs of L. rugulipennis on strawberries surrounded by a barrier strip of M. recutita compared to those without a barrier, but overall there were no consistent reductions in populations of the pest. Numbers of L. rugulipennis on the trap plant were small until late August. In a similar experiment using an alternative trap plant, Medicago sativa, no significant reductions in the numbers of L. rugulipennis were found on strawberries with the trap barrier, despite large numbers of the pest insect being found on this trap plant.Although predatory arthropods such as spiders, Orius spp., and nabids, and hymenopterous parasitoids were found on the trap plants, there was no indication that they became more numerous on the strawberry plots inside these barriers than on those without surrounding trap plants.     

Distribution and abundance of adult Opomyza florum (Diptera: Opomyzidae) in cereal crops and grassland

From 1971 to 1979 counts were made of the numbers of Opomyza florum adults found in vacuum net samples taken from cereal and grass fields on a 62-km² study area in West Sussex. In 2 years, 1974 and 1975, counts were made of the numbers of adults found in similar samples taken from hedgerow grasses. In all years, numbers of adults were highest in winter wheat crops; relatively few were found in other autumn- or spring-sown cereals or in grass fields. Mean numbers (/m²) in winter wheat in June varied from 33.0 in 1974 to only 0.9 in 1977. In most years, the first adults were found in June in winter wheat; numbers reached a peak in July and then declined rapidly. More adults were usually found in winter wheat crops that followed winter wheat in the rotation than in those following grass. Adults were also more abundant in June in winter wheat crops sown relatively early than in those sown late. The current tendencies towards earlier drilling of winter wheat and to the growth of successive wheat crops could increase the pest status of O. florum.     

Life History of Ilybius fenestratus (Fabricius) (Coleoptera,Dytiscidae) in a Central Norwegian Lake

The life history of Ilybius fenestratus was studied in Målsj?en, a lake in S?r-Tr?ndelag, Central Norway (63°14'N, 10°26'E), during 1971–1972. Adults and larvae were sampled in activity traps every week during March–October and every 2–3 weeks during November–February. Newly-emerged adults were generally found from mid-July to September, and after overwintering in torpidity, probably in the water, they again appeared in the second half of June to August/September. Laying of eggs took place from early/mid July to early August. Larvae occurred in the traps from late July to early May. I. fenestratus was thus found to be a semivoltine summer breeder, with overwintering larvae the first winter and overwintering adults the next. Both adults and larvae lived in large areas of the lake's littoral zone.     

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.     

Biology of the threespine stickleback,Gasterosteus aculeatus,and the blackspotted stickleback,G. wheatlandi,during their marine pelagic phase in the Bay of Fundy,Canada

Synopsis Two species ofGasterosteus were collected from the surface waters of 48 stations in the Bay of Fundy from 1979–1982. Densities varied widely according to locality and time of year (range: 1 fish 0.2 m^–2 to 1 fish 26.3 m^–2 of sea surface) but peaked within 30 km of the New Brunswick/Maine coast in July and August. A few adults were caught as far as 100 km from the coast in winter. Guts ofG. wheatlandi were significantly fuller (63.3 ± 0.6%) than those ofG. aculeatus (44.6 ± 0.1%) but there were no differences between male and female guts within species. Quantitatively, gut contents were very similar between species, consisting primarily of (99.4%): calanoid copepods (Centropages typicus Kroyer andEurytemora cfamericana Williams), copepod nauplii, cladocerans (Podon leuckarti Sars andP. polyphemoides Leuckart) and planktonic eggs (in decreasing order of importance).Gasterosteus wheatlandi ate significantly more calanoids thanG. aculeatus but all other prey types were eaten in similar amounts. Within species, there were no differences in the numbers of each prey type eaten over time. The most abundant calanoid species caught alongside the fishes in the sampling nets did not occur in the sticklebacks' diets; probably they were too large to be ingested.Gasterosteus aculeatus bred in inshore, brackish water ponds in late April. By late July most juveniles had migrated out into the Bay but a few remained until early September.Gasterosteus wheatlandi bred later in the brackish water ponds (late May) and juveniles began migrating into the Bay in early August; a few remained in the ponds until early September. Adults were found in the Bay alongside juveniles suggesting that individuals of both species may survive for a second year. In both species, growth rates of juveniles were greater in brackish water than in the sea.     

Effects of interspecific competition on development and reproduction in two giant water bugs,Diplonychus japonicus vuillefroy andDiplonychus major esaki (Hemiptera: Belostomatidae)

We studied the interpecific competition between 2 species of predatory aquatic bugs, Diplonychus japonicus and D. major by conducting a field experiment. We set up 3 types of experimental plots in the paddy fields where D. major predominated. The two plots contained single species of either D. japonicus or D. major, respectively, and one plot had both species in equal number. We compared the development and the reproductive performance between plots in each species. In D. japonicus, the number of eggs and early instar nymphs were significantly smaller in the plots containing both species than in the monospecific plots. However, the numbers of late instar nymphs and newly emerged adults were not significantly different between plots. The proportions of starved nymphs in both plots were larger than those in the D. japonicus's natural habitats. The final densities of adults in both plots were lower than those in the natural habitats. These results suggest that lower density of D. japonicus in these paddy fields is due to the lack of available food for nymphs rather than the effects of interspecific competition with D. major. In D. major, significant differences were not found in the number of eggs, each instar nymphs and adults. These results suggest that the effects of interspecific competition did not affect the reproductive performance of D. major.     

Some observations on the distribution and life history of Caenis robusta Eaton (Ephemeroptera) in Cheshire and North Shropshire,England

Caenis robusta Etn. was found in only 8 of 107 water bodies sampled. All the habitats from which it was recorded contained plant debris; the waters were still or slow-flowing and had conductivities ranging from 120–687 µmhos cm^–1 at 25°C.In North Shropshire, England, C. robusta had one generation per year. Newly hatched nymphs were abundant in August and growth occurred rapidly until September. No growth took place from October until March but was again rapid from April until June. Emergence took place at dusk in late June and July.     

Vertical dispersal of the two-spotted spider mite Tetranychus urticae, and the predatory mite Phytoseiulus persimilis on dwarf hops

1 The pattern of dispersion within plants of the two-spotted spider mite, Tetranychus urticae, and its predator, the phytoseiid Phytoseiulus persimilis, was studied on the dwarf hop variety First Gold from May to September in 1997 and 1998. 2 Spider mite populations developed on the lower leaves initially but, by late July, as the numbers of mites increased, most were found towards the top of plants. From early August, the numbers of spider mites decreased most rapidly on the upper parts of plants. 3 Where P. persimilis was released, the predator maintained the numbers of T. urticae below those found on non-release plots throughout the season. 4 By early August, the predator’s pattern of dispersion was similar to that of the pest. 5 Predators spread to non-release plots by 20 June in 1997 and 24 July in 1998 and eventually became more numerous than on the plots where they had been released.     

Aphid colonization of spring cereals

In 1970-1, Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae were the commonest alatae trapped from April/May to August, with most in July and early August. The first alatae appeared in the Rothamsted survey suction trap 0–34 days before aphids were found on the cereals, but during May and June no relationship was found between the numbers trapped and the number on the crop. Most species occurred first near the sheltered edge of the crop, but M. dirhodum was widespread over the field. Most infestations were quickly dispersed by the movements of older morphs; adults only stayed in one place for about 2 days. Alate M. dirhodum moved more often than apterae, but both morphs of S. avenae moved equally often and more frequently between larvipositions than did those of M. dirhodum. Apterae deposited more nymphs in a ‘group’ than alatae, and M. dirhodum deposited more than S. avenae. Few ‘groups’ persisted for more than a week. Although M. dirhodum occupied the crop area faster than S. avenae, all 0–3 m lengths of row sampled being infested within 2–5 wk of their first appearance, most or all of the tillers were colonized only in late July 1970.     

Utilization of early soybeans for food and reproduction by the tarnished plant bug (Hemiptera: Miridae) in the delta of Mississippi

Commercially produced maturity group (MG) IV soybeans, Glycine max L., were sampled during bloom for tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), during May and June 1999 (3 fields) and 2001 (18 fields). The adults and nymphs were found primarily in single population peaks in both years, indicating a single new generation was produced during each year. The peak mean numbers of nymphs were 0.61 and 0.84 per drop cloth sample in 1999 and 2001, respectively. Adults peaked at 3.96 (1999) and 3.76 (2001) per sweep net sample (25 sweeps). Tests using laboratory-reared and field-collected tarnished plant bugs resulted in very poor survival of nymphs on 16 different soybean varieties (MG III, one; IV, four; V, nine; VI, two). A large cage (0.06 ha) field test found that the number of nymphs produced on eight soybean varieties after mated adults were released into the cages was lower than could be expected on a suitable host. These results indicated that soybean was a marginal host for tarnished plant bugs. However, the numbers of adults and nymphs found in the commercially produced fields sampled in the study may have been high enough to cause feeding damage to the flowering soybeans. The nature of the damage and its possible economic importance were not determined. Reproduction of tarnished plant bugs in the commercially produced early soybean fields showed that the early soybeans provided tarnished plant bugs with a very abundant host at a time when only wild hosts were previously available.     

Prevalence and abundance of Ixodes pacificus immatures (Acari: Ixodidae) infesting western fence lizards (Sceloporus occidentalis) in northern California: temporal trends and environmental correlates.

The prevalence and abundance of immature Ixodes pacificus ticks on western fence lizards (Sceloporus occidentalis) were examined in relation to time of year, host attributes (i.e., age, gender, and presence or absence of blood parasites), and 5 environmental characteristics, including topographic exposure and ground cover substrate, over a 2-year period in northern California. Lizards were infested with subadult ticks from early March until late July or early August, with peak median numbers of larvae and nymphs recorded in late April and early May of both years. Peak larval and nymphal abundances differed between years. The overall ratio of larvae to nymphs on adult male lizards was low, ranging from 0.80 in 1999 to 2.41 in 2000. Such intensive feeding of nymphs versus larvae on these lizards, which are reservoir-incompetent for Borrelia burgdorferi spirochetes, may explain previous observations of decreasing spirochetal infection prevalence from the nymphal to adult stage in northwestern California. Adult male lizards were more likely to be infested with nymphs and harbored greater abundances of larvae and nymphs than adult females. Lizards uninfected with blood parasites had more nymphs than infected lizards. The measured environmental characteristics could explain only a small percentage of the total variation observed in larval prevalence (22%) and in larval and nymphal abundance (12 and 3%, respectively).     

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 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.     

茴香薄翅野螟发生动态的调查

经调查研究表明:在青海省的油菜种植区,茴香薄翅野螟Evergestis extimalis Scopoli越冬幼虫从6月初开始化蛹,6月中旬化蛹率达为80%,到6月下旬化蛹率达到100%;成虫于7月上旬开始羽化,7月15～20日为成虫羽化高峰;田间卵始见期为6月下旬至7月上旬,7月中旬达到产卵高峰期;越冬幼虫平均死亡率为96.63%。     

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.     

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.