小型啮齿动物寄主革螨一些生态特点观察

宿主背部螨数超过腹部，育幼巢螨数最多，旧巢螨数亦多，新巢最少。育幼鼠螨指数最高，旧巢内的鼠螨指数亦高，新巢内者最代，宿主死后８小时内多数螨离开尸体，２４小时几乎全部离开尸体。多数螨在阴暗处可活５天，最多１０天。多数螨在烈日下２小时内死亡，３小时全部死亡。     

东北血革螨生态学研究

东北血革螨活动的适温为10—25℃。40±1℃时10分钟全部死亡。爬行速度与温度的关系呈Y=a+b logX型指数曲线,35±1℃时爬速最快。爬行速度在不同光照处无明显差别。活动不受光线影响,绝大多数螨绕圈爬行,少数螨爬行方向无规律。该螨多数在宿主死后6—7小时内离开鼠尸,至24小时全部离开。亦随时离开活宿主体。夏季饥饿螨在阴暗处玻璃皿内4日全部死亡。在东北平原和青藏高原发现该螨宿主12种。该螨指数在达乌尔黄鼠体表和喜马拉雅旱獭巢内夏季最低,在黑线仑鼠体表夏季最高。     

我国北方几种蚤离开宿主的野外观察

夏季,于吉林省西部草原,宿主处死后12小时内其寄生蚤大部离开宿主尸体,至24小时全部离开。于青海高原,旱獭处死后24小时内,只有少数蚤离开獭尸,至48小时才大部离开,也有至120小时才离开的。     

二齿新蚤和方形黄鼠蚤松江亚种侵袭与离开宿主习性的实验研究

本文对二齿新蚤和方形黄鼠蚤松江亚种侵袭与离开宿主的习性进行了实验研究,结果：(1)蚤攻击宿主距离平均在2cm以内,最大攻击距离不超过10cm。在有效侵袭范围内,蚤与宿主距离近时较距离远时吸血蚤数增多。(2)蚤对宿主的侵袭程度雌蚤大于雄蚤,繁殖蚤大于新羽化蚤,二齿新蚤大于方形黄鼠蚤松江亚种,对小白鼠大于对达乌尔黄鼠。(3)宿主死后一定时间内,仍有部份蚤侵袭其尸体。 死亡时间越长侵袭蚤数越少,呈logY=a-blogX型曲线。(4)蚤离开宿主时间呈偏态分布,温度越高偏态分布越明显。蚤离开死鼠和离开活鼠所需时间很接近。 二齿新蚤和方形黄鼠蚤松江亚种离开宿主时间几乎相同。二种蚤离开宿主平均时间与环境温度呈负相关,且呈曲线关系。     

小型哺乳动物寄生革螨的数量等级和寄主关系

在吉林省西部草原地区共调查小型哺乳类动物13种,获革螨39种。其中,优势种8种、常见种10种、稀有种21种。其与寄主的关系,多数螨为多寄主,?个别者为单寄主。优势种和常见种螨的巢内指数均大于寄主体上指数。     

二齿新蚤和方形黄鼠蚤松江亚种吸血习性的实验室观察

1983—1989年对二齿新蚤和方形黄鼠蚤松江亚种几种吸血习性进行了实验观察。1.新羽化蚤吸血蚤百分率与羽化后时间呈直线正相关。二齿新蚤至30小时左右,方形黄鼠蚤松江亚种至40小时左右,吸血蚤百分率约达90%,相当于繁殖蚤。2.蚤同宿主接触5分钟内即有部份吸血。接触半小时吸血蚤数最多,半小时至1小时吸血蚤数减少,也有少部份蚤至1小时尚未吸血。3.吸血蚤与未吸血蚤均可留于宿主体上,亦均能随时离开宿主体。     

格氏血厉螨的生态学研究

1983—1984年对格氏血厉螨的某些生态学特点进行了研究,其中包括对温度的选择;爬行进度与温度的关系;爬行方向;离开宿主时间与温度的关系;离开死鼠和离开活鼠所需的时间;高温的作用;对光的反应;饥饿螨在阴暗处玻璃皿内的存活时间;对宿主的寄生程度;季节消长等.     

北京小龙门东方中杜鹃多重寄生冕柳莺的报道

多重巢寄生是1只或多只寄生性鸟类在1个宿主巢内产2枚或多枚卵的特殊行为方式。对于雏鸟具有排他性的杜鹃而言,多重寄生被认为是种内个体之间或种间的一种竞争,但相关报道较少。通过野外观察和分子生物学检测技术,我们在北京小龙门国家森林公园确定了一个被东方中杜鹃(Cuculus optatus)多重寄生的冕柳莺(Phylloscopus coronatus)巢。     

贵州省部分鼠形动物体表革螨群落结构

本文汇集了1978—1988年贵州省17个县(市)的调查资料,首次对啮齿目及食虫目动物体表革螨群落结构进行了定量描述。多数宿主体表革螨种类丰富。除部分稀有种外,多数革螨宿主广泛。毒厉螨、土尔克厉螨及柏氏禽刺螨可作为多种宿主的优势革螨种。优势种在群落中的地位受物种丰富度、均匀度及多样性的影响。     

云南省微板无前恙螨的初步研究

为探索云南省微板无前恙螨Walchia micropelta的分布规律及感染情况,2001—2015年选取云南省33个县(市)进行恙螨的现场调查,统计分析微板无前恙螨的构成比、感染率、平均多度和感染度,并比较其在不同生境、地域和海拔的感染差异。采用扩散指数、I指数、聚块指数和CA指数分析微板无前恙螨的空间分布型;用协调系数分析微板无前恙螨和葛洪无前恙螨W.koi的种间协调关系。结果显示,在22个调查点采集到微板无前恙螨4 014只,占全部恙螨的3.15%,且广泛分布于20种宿主体表;微板无前恙螨多采集于云南省南部,在低海拔地区、山区和室外生境的数量丰富;不同年龄宿主体表的微板无前恙螨的感染存在差异,成年宿主恙螨的构成比、感染率和平均多度均高于未成年且有统计学意义(P 0.05);微板无前恙螨与葛洪无前恙螨在黄胸鼠Rattus tanezumi体表存在正协调关系(V=0.12,P 0.05)。由此可见,云南省微板无前恙螨分布广泛,但其宿主特异性低,多聚集分布于啮齿动物上。地域、海拔、宿主的种类和年龄等因素对微板无前恙螨的感染有影响。     

Mesostigmatid mite infestations of rodents in diverse biotopes of central and southern India

Examination of 165 rodents trapped in domestic, peridomestic, and feral biotopes of central and southern India revealed the presence of 1,359 mesostigmatid mites. Rodents in central India were infested with 1 species of mite, Laelaps nuttalli; 98% of these mites were recovered from the peridomestic rodent Bandicota bengalensis. Material from the burrow nest of a peridomestic rodent examined in central India revealed the mite, Hypoaspis miles. Rodents from the diverse biotopes of southern India were infested by 8 species of mites: L. nuttalli, Laelaps buxtoni, Laelaps myonyssognathus, Androlaelaps aduncus, Androlaelaps marshalli, Androlaelaps sp. A, Hypoaspis sp. 1, and Hypoaspis sp. 2. Sheep from nearby villages regularly graze in feral biotopes. From the hair of these sheep, 2 species of mesostigmatid mites were recovered, A. aduncus and A. marshalli. The sheep appeared to aid the dispersal of rodent-infesting mites passively. Laelaps nuttalli was the predominant mite species found on the peridomestic rodent B. bengalensis. In both central and southern India, the prevalence, mean intensity, and relative density of this mite were much higher on peridomestic rodents than on domestic and feral rodents. A significant negative correlation was found between the numbers of mites and fleas infesting rodents in central India. A highly significant positive association between A. marshalli and A. aduncus on the feral rodent Tatera indica was recorded. In southern India, the overall prevalence of the 8 species of mites was highest on Mus platythrix. However, the combined prevalence of these mites on 2 feral rodents T. indica and M. platythrix was lower than their prevalence on B. bengalensis. Similarly, the combined values for mean intensity and relative density of these mites on the 2 feral rodents were lower than on the peridomestic rodent B. bengalensis.     

Comparative growth and development of the metacercariae of Fibricola seoulensis (Trematoda: Diplostomidae) in vitro, in vivo and on the chick chorioallantois

The growth and development of the metacercariae of F. seoulensis cultivated in vitro or on the chick chorioallantois were assessed by comparison with the optimum process of maturation in albino rats and new born chickens. The process of maturation was divided for convenience into six stages: Stage 1; cell multiplication, Stage 2; body shaping, Stage 3; separation of genital anlagen, Stage 4; organogeny, Stage 5; gametogony, and Stage 6; oviposition. In Hank's and Tyrode's solutions, the metacercariae were alive up to 200 days or more at 4 degrees C without any development. The in vivo maturation process in rats or chicks was as follows: stage 1 from 6 hours; stage 2 from 24 hours; stage 3 from 48 to 72 hours; stage 4 from 3 to 4 days; stage 5 from 4 to 5 days; and stage 6 from 5 to 8 days. Despite unsuccessful infection of the metacercariae to 12 day old chicks, fully mature worms of stage 5 or 6 were recovered from new born chicks (1 to 2 days old). The metacercariae of F. seoulensis grown in vitro were up to stage 3 and no further maturation was observed. Of various media employed, the medium NCTC 109 (Gibco) or NCTC 135 (Gibco) supplemented with 20% egg yolk or 20% whole egg macerate or 0.5% yeast was basically required for the earlier development of the fluke. It took 16.1 days (in average) to reach the stage 3 after cultivation. The metacercariae cultivated on the chorioallantoic membranes of 6-13 day old chick embryo at 37-38 degrees C showed their full development up to stage 5 or 6. However, the worms were in general remarkably retarded, compared with those grown in rats or chickens. In the experiments of worm transplant, although the transfer was failed from in vitro culture to in vivo of rats (per os), the transplants from in vitro culture to the chorioallantois and from the chorioallantois to in vivo of rat host were successful with or without development of the transferred worms. In the present study, it was observed that the metacercariae of F. seoulensis can be maintained in vitro media with poor development as well as fully matured in 1 to 2 day-old chicks or on the chorioallantois at a very low rate.     

Sitting ducklings: Timing of hatch,nest departure,and predation risk for dabbling duck broods

For ground‐nesting waterfowl, the timing of egg hatch and duckling departure from the nest may be influenced by the risk of predation at the nest and en route to wetlands and constrained by the time required for ducklings to imprint on the hen and be physically able to leave the nest. We determined the timing of hatch, nest departure, and predation on dabbling duck broods using small video cameras placed at the nests of mallard (Anas platyrhynchos; n = 26), gadwall (Mareca strepera; n = 24), and cinnamon teal (Anas cyanoptera; n = 5). Mallard eggs began to hatch throughout the day and night, whereas gadwall eggs generally started to hatch during daylight hours (mean 7.5 hr after dawn). Among all species, duckling departure from the nest occurred during daylight (98%), and 53% of hens typically left the nest with their broods 1–4 hr after dawn. For mallard and gadwall, we identified three strategies for the timing of nest departure: (a) 9% of broods left the nest the same day that eggs began to hatch (6–12 hr later), (b) 81% of broods left the nest the day after eggs began to hatch, and (c) 10% of broods waited 2 days to depart the nest after eggs began to hatch, leaving the nest just after the second dawn (27–42 hr later). Overall, eggs were depredated at 10% of nests with cameras in the 2 days prior to hatch and ducklings were depredated at 15% of nests with cameras before leaving the nest. Our results suggest that broods prefer to depart the nest early in the morning, which may best balance developmental constraints with predation risk both at the nest and en route to wetlands.     

Movements and Resource Selection of Fledgling Goshawks in Montane Forests of Southeastern British Columbia

ABSTRACT The northern goshawk (Accipiter gentilis) has been the subject of considerable interest because of the impact of logging on this species' nesting habitat. However, few studies have examined movements of fledgling birds around the nest prior to independence, and even fewer have described resource requirements of young birds during their postfledging period. Over 3 years, we followed 31 radiotagged goshawk fledglings from 15 nests in southeastern British Columbia, Canada. Of these birds, 26 survived to disperse. Between fledging and dispersal 95% of fledgling relocations (n = 1, 148) were within 450 m of the nest. Fledglings primarily remained within 298 m of the nest during the first 21 days postfledging and within 525 m of the nest between 21 days postfledging and dispersal. Fledglings' movements were highly directional, with individual and sibling movements away from any particular nest tending out in one direction. Postfledging areas averaged 36.7 ha in size (median = 23.1, inter-quartile range = 20.8–39.7 ha). Fledglings strongly avoided forest <40 years old and weakly selected young forests (40–80 yr), mature forests (>80 yr), and stands with >40% canopy cover during the first 21 days and after. We suggest forest managers wishing to conserve goshawk postfledging areas in the interior montane forests of British Columbia maintain forests >40 years old with high crown closure covering an area ≥21 ha and preferably >40 ha. This area should contain all identified occupied and alternative nest trees in a nest area. At least half this area should be forest >80 years old and contain existing nests and potential for future nest trees.     

The short-term regulation of foraging in harvester ants

In the seed-eating ant Pogonomyrmex barbatus, the return ofsuccessful foragers stimulates inactive foragers to leave thenest. The rate at which successful foragers return to the nestdepends on food availability; the more food available, the morequickly foragers will find it and bring it back. Field experimentsexamined how quickly a colony can adjust to a decline in therate of forager return, and thus to a decline in food availability,by slowing down foraging activity. In response to a brief, 3-to 5-min reduction in the forager return rate, foraging activityusually decreased within 2–3 min and then recovered within5 min. This indicates that whether an inactive forager leavesthe nest on its next trip depends on its very recent experienceof the rate of forager return. On some days, colonies respondedmore to a change in forager return rate. The rapid colony responseto fluctuations in forager return rate, enabling colonies toact as risk-averse foragers, may arise from the limited intervalover which an ant can track its encounters with returning foragers.     

Of mice and mallards: positive indirect effects of coexisting prey on waterfowl nest success

Coexisting prey species interact indirectly via their shared predators when one prey type influences predation rates of the second prey type. In a temperate system where the predominant shared predator is a generalist, I studied the indirect effects of rodent populations on waterfowl nest success, both within the nesting season among sites and among years. Among six to ten upland fields (14 to 27 ha), mallard ( Anas platyrhynchos ) nest success was positively correlated with rodent abundance in all three years of the study. After removing year effects, mallard nest success remained positively correlated with the relative abundance of rodents. Of the rodent species present, California voles ( Microtus californicus ) were the most important coexisting prey type influencing nest success. Among years, mallard nest success was positively correlated with vole abundance; the asymptotic relationship suggests a threshold response to vole abundance, beyond which predators become satiated and additional voles do little to affect nest success. I tested and rejected three alternative explanations for the observed positive correlation between mallard nest success and rodent abundance that do not involve an indirect effect of coexisting prey populations. The influences of dense nesting cover, nesting density, and predator activity did not explain the observed patterns of nest success. These results suggest that rodent populations buffer predation on waterfowl nests, both within and among years, via the behavioral responses of shared predators to coexisting prey.     

Habitat-specific life-history variation in the Caribbean termite Nasutitermes acajutlae (Isoptera: Termitidae)

Abstract.  1. Population and individual colony characteristics of Nasutitermes acajutlae on St John, U.S. Virgin Islands were studied over a 5-year period.
2. Four habitat types (dry forests, moist forests, sparse vegetation, and woodlands) were sampled for N. acajutlae , using quadrat-based methods. Lying dead wood was also quantified in the same sites.
3. Habitats differed significantly in the volume of lying dead wood, and total termite nest volume within quadrats was positively related to wood volume. It was hypothesised that the volume of dead wood affected growth, reproduction, and yearly survival of individual colonies.
4. In a sample of > 100 colonies assessed in 1998, 2000, 2001, and 2002, no significant differences in the growth rate of colonies (= increase in nest volume) could be found between habitat types; however, colonies in sparse vegetation were smaller, less likely to survive, and reproduced at a smaller size compared with those in the other three habitats.
5. Overall nest volume in sparse vegetation was high, compared with dry and moist forest, but colonies showed, on average, poorer survival (interpreted as lower fitness), and produced alates at an early stage of development. Optimum habitat characteristics for N. acajutlae may include not only favourable microclimate but also the reliable acquisition of new dead wood after storms.     

Necromenic life style of Histiostoma polypori (Acari: Histiostomatidae)

Histiostoma polypori (Histiostomatidae, Astigmata) is associated with the earwig Forficula auricularia, which has an interesting brood behavior: the adult earwig female cares for her eggs and stays with the N2 and N3 nymphs in the nest. Deutonymphs of H. polypori only leave the female earwig to develop on dead earwig N2 and N3 nymphs. The newly molted deutonymphs attach to live earwig N3 nymphs. The earwig’s cleaning behavior displaces the deutonymphs to the exuvial suture, around the area between cephalon and prothorax. From there, deutonymphs switch from one earwig stage to the following, always occupying that region. Histiostoma polypori obviously has a necromenic life style, that is, it ascends a carrier organism and develops on the carrier’s cadavers. Necromeny within the Histiostomatidae presumably derived at least twice convergently from phoretic transport.     

Testing common assumptions in studies of songbird nest success

We studied Ovenbird Seiurus aurocapilla and Golden‐winged Warbler Vermivora chrysoptera populations in northern Minnesota, USA, to test two common assumptions in studies of songbird nest success: (1) that the condition of an empty nest on or near its expected fledge date is an indicator of nest fate; and (2) that the presence of a fledgling or family group within a territory confirms a successful nest in that territory. We monitored the condition of nests and used radiotelemetry to monitor juveniles through the expected fledging date and early post‐fledging period. Of nests that contained nestlings 1–2 days before the expected fledge date, fates were misidentified using nest condition alone for 9.5% of Ovenbird nests, but those misidentifications were made in both directions (succeeded or failed), yielding only a small bias in estimated nest success. However, 20% of Golden‐winged Warbler nests were misidentified as successful using nest condition during the final visit interval, biasing the nest success estimate upward by 21–28% depending on the treatment of uncertain nest fates. Fledgling Ovenbirds from 58% of nests travelled beyond their natal territory within 24 h, rising to 98% after 5 days, and those fledglings travelled up to 390 m from nests within 10 days of fledging. Fledgling Golden‐winged Warblers from 13% of nests travelled beyond their natal territory within 24 h, rising to 85% after 5 days, and those fledglings travelled up to 510 m from nests within 10 days of fledging. We conclude that nest condition and fledgling presence can be misleading indicators of nest fate, probably commonly biasing nest success estimates upward, and we recommend that these assumptions should be tested in additional species.     

Review. When to leave the brood chamber? Routes of dispersal in mites associated with burying beetles

Most nests of brood-caring insects are colonized by a rich community of mite species. Since these nests are ephemeral and scattered in space, phoresy is the principal mode of dispersal in mites specializing on insect nests. Often the mites will arrive on the nest-founding insect, reproduce in the nest and their offspring will disperse on the insect's offspring. A literature review shows that mites reproducing in the underground brood chambers of burying beetles use alternative routes for dispersal. For example, the phoretic instars of Poecilochirus spp. (Mesostigmata: Parasitidae) disperse early by attaching to the parent beetles. Outside the brood chamber, the mites switch host at carcasses and pheromone-emitting male beetles, where juvenile and mature burying beetles of several species congregate. Because they preferably switch to beetles that are reproductively active and use all species of burying beetles within their ranges, they have a good chance of arriving in a new brood chamber. Other mite associates of burying beetles (Alliphis necrophilus and Uropodina) disperse from the brood chamber on the beetle offspring. We suggest that these mites forgo the possible time gain of dispersing early on the parent beetles because their mode of attachment precludes host switching. Their phoretic instars, once attached, have to stay on their host and so only dispersing on the beetle offspring guarantees that they are present on reproducing burying beetles of the next season. The mites associated with burying beetles providean example of multiple solutions to one life history problem – how to find a new brood chamber for reproduction. Mites that have mobile phoretic instars disperse on the parent beetles and try to arrive in the next brood chamber by host switching. They are independent of the generation cycle of a single host and several generations of mites per host generation are possible. Mites that are constrained by their mode of attachment disperse on the beetle offspring and wait until their host becomes mature and reproduces. By doing this they synchronize their generation time with the generation time of their host species. Exp Appl Acarol 22: 621–631 © 1998 Kluwer Academic Publishers