首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 312 毫秒
1.
Since its introduction from Asia, the brown marmorated stink bug, Halyomorpha halys (Stål), has become a pest of many agricultural crops in the USA. Insect predators utilize H. halys as prey; however, the chemical cues used by them in prey location are largely unknown. Here, we hypothesized that tridecane, an H. halys-associated volatile, acts as a kairomone for the predaceous minute pirate bug, Orius insidiosus (Say). We conducted laboratory, greenhouse, and field experiments to: (1) assess the attraction of adult O. insidiosus to H. halys-damaged bean pods and tridecane in cage studies, and its effect on egg predation; (2) video record the behavioral response of O. insidiosus males and females to tridecane in a four-arm olfactometer; and (3) test whether Orius spp. are attracted to tridecane-baited sticky traps in peach, blueberry, and sunflower fields, and its effect on egg predation. In the greenhouse, O. insidiosus was attracted to H. halys-damaged pods and artificial plants baited with tridecane in the presence of prey (sentinel eggs); however, this attraction rarely led to increased egg predation. Although both O. insidiosus males and females spent more time in the arm of the olfactometer with tridecane, males were more responsive at a lower concentration than females. Similarly, Orius spp. were more attracted to tridecane-baited than unbaited traps in the field; however, there was no effect on egg predation. Altogether, while O. insidiosus is attracted to tridecane, this attraction did not always lead to higher predation, suggesting that this kairomone likely acts as an arrestant.  相似文献   

2.
The development of biological control measures to reduce the impact of invasive species is a desired goal. Rhabdias species have recently been advocated as biological control agents for invasive anurans. This study describes a field-based approach to support laboratory results on the potential impact of the lung nematode Rhabdias pseudosphaerocephala on the prey consumption of its host, the invasive cane toad (Rhinella marina, Bufonidae). Toads were sampled from various populations in the Wet Tropics of Australia during the wet seasons of 2010 and 2012. Consumed prey items were counted in 212 cane toads and identified to class and order levels and the number of lung nematodes was counted for each toad. The number of R. pseudosphaerocephala in free-ranging cane toads affected negatively the diversity of prey items consumed, but was not related to the number of prey items or the number of ants consumed. The results suggest that infection of free-ranging cane toads by the lung nematode reduces their range of prey items. Possible reasons could be a reduced locomotor activity resulting in changes of foraging modes of infected toads which was reported from some laboratory trials. Infection of cane toads by R. pseudosphaerocephala may therefore have the potential to alter the impact of cane toads on invertebrate communities and their competition for food resources with native Australian anurans.  相似文献   

3.
Feeding capacity of adultN. elongatum was tested at different prey quantities of the bark beetlePityogenes chalcographus L. (Scolytidae) in artificial galleries. Maximum feeding capacity of 2.P. chalcographus/day was observed when 3 prey items/day were offered. There was no increase in prey consumption with further increase of prey quantities, i. e. there was no functional response. Possible reasons for restricted feeding capacity are discussed. It is suggested thatN. elongatum adults exhibit a “threshold strategy” which tends to reach an optimum feeding level instead of a maximum food intake. The consequences of restricted feeding capacity for limiting bark beetle populations are discussed.  相似文献   

4.
A purified Arabinogalactan-Protein composition (LL-4218) was prepared from the leaves of Argemone mexicana to treat psoriasis. The effect of (LL-4218) was evaluated on reproductive (male and female fertility) and developmental toxicity in rats. LL-4218 was administered orally at the doses of 250, 500 and 1000 mg kg− 1. The results showed that LL-4218 did not produce any significant dose related changes in reproductive and developmental toxicity studies. Therefore, it is concluded that LL-4218 did not produce any significant toxic effect on reproduction and developmental parameters of rats and NOAEL for reproductive and developmental toxicity studies in rats was 1000 mg kg− 1.  相似文献   

5.
Morphological characteristics of immature developmental stages of Rhyzobius lophanthae Blaisdell (Col.: Coccinellidae), predator of scale insects of the family Diaspididae (Homoptera), are described. Data about the morphology of eggs, the four larval instars, and the pupa is presented. Larval instars are described in more detail: size of head capsule, length of tibia, distribution of dorsal and lateral setae of abdomen segments for each larval instar is reported. Distribution of spiracles is also given. Study on the biology concerns the influence of prey on the duration of instar periods. The diaspidids Aspidiotus nerii and Aonidiella aurantii were used as food. The mean duration of the developmental period from egg to adult was 27.1 days, and no mortality was observed (0?%) when A. nerii was used as prey. The respective numbers when the prey was A. aurantii were 48.8 days and 84?%.  相似文献   

6.
Thrips tabaci Lind. is very difficult to control and thus one of the most important pests of leek in Europe. As an alternative to insecticides biological control may be carried out by making use of beneficial insects, the Coccinellidae being one of the most important predatory families. In the present study laboratory trials were carried out withHippodamia convergens Guer.-Men., one of the polyphagous representatives of the lady birds, to figure out the feeding activity, development and prey preference ofH. convergens against the onion thrips in comparison with two aphid species. H. convergens developed fully when fed exclusivelyT. tabaci larvae, although mortality was considerably higher and development took much longer. When fed thrips the complete development lasted 29,8 days on an average, the mortality reaching 88%. When offeredAcyrthosiphon pisum (Harris)H. convergens took only 24 days for development with a mortality of only 16%. Above all, the fourth larval instar and the pupa suffered from a very high mortality, reaching 45 and 50% respectively. WithA. pisum as a prey mortality decreased to only 6%. The duration of the pupal development was not affected by the prey species. The feeding activity ofH. convergens increased significantly during the development. The larvae of the second and fourth instar predated 28 and 170 thrips larvae respectively per day as a maximum. The adults achieved the highest feeding activity, predating more than 300 thrips larvae in 24 hours. When adding up the number of prey individuals per day for each developmental instar, the L2 larvae predated more than 90 and the L4 larvae more than 1000 thrips larvae. When offered thrips larvae andMyzus persicae (Sulz.) simultaneously, there was an increasing prey preference during the development ofH. convergens from first larval instar to adult. As to the last instars there was 20–25% less predation of thrips larvae compared to the aphids during 24 hours.  相似文献   

7.
Observations and food analysis made in Beynam forests near Ankara, Turkey in 1981 showed that four species of titmice studied (Parus major, P. caeruleus, P. ater. P. lugubris anatoliae) fed their prey animals chiefly in the top of trees. Solely about 1,5% of prey descended from the air and 10% from the soil surface. The titmice proved to be important predators of forest insect pests. The three pest species:Euproctis chryorrhoea, Tortrix viridana andDiprion pini, amounted to 45–71% of the food of titmice.  相似文献   

8.
Spirotetramat is a new systemic insecticide listed in Group 23 of the IRAC mode-of-action classification scheme as an inhibitor of lipid biosynthesis. Side effects assessment on key natural enemies is necessary before incorporating a pesticide in IPM programs. Herein, lethal and sublethal side effects of spirotetramat on adults and larvae of Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) were evaluated under laboratory conditions by topical application and by ingestion of treated individuals of Planococcus citri Risso (Hemiptera: Pseudococcidae). The lethal and sublethal effects of spirotetramat were compared to those of chlorpyriphos and pyriproxyfen, two insecticides commonly used in Spanish citrus. Spirotetramat resulted harmless: (1) when directly applied on larvae and adults of C. montrouzieri, since it did not affect survival, longevity, fecundity, egg hatching, and offspring survival. In contrast, chlorpyriphos was classified as moderately toxic for adults due to its effects on fecundity, egg hatching and offspring survival. Pyriproxyfen was classified as harmful for larvae due to the acute effect on pupal mortality. When larvae and adults of C. montrouzieri were fed with treated prey, spirotetramat was also classified as harmless. Adults of C. montrouzieri fed with pyriproxyfen-treated prey exhibited increased fecundity but no eggs hatched. Moreover, the larvae fed on pyriproxyfen-treated prey did not reach the adult stage. The results of this study indicate that spirotetramat may be compatible with augmentative releases of C. montrouzieri in citrus.  相似文献   

9.
Climate warming is already influencing plant migration in different parts of the world. Numerous models have been developed to forecast future plant distributions. Few studies, however, have investigated the potential effect of warming on the reproductive output of plants. Understorey forest herbs in particular, have received little attention in the debate on climate change impacts.This study focuses on the effect of temperature on sexual reproductive output (number of seeds, seed mass, germination percentage and seedling mass) of Anemone nemorosa L., a model species for slow colonizing herbaceous forest plants. We sampled seeds of A. nemorosa in populations along a 2400 km latitudinal gradient from northern France to northern Sweden during three growing seasons (2005, 2006 and 2008). This study design allowed us to isolate the effects of accumulated temperature (Growing Degree Hours; GDH) from latitude and the local abiotic and biotic environment. Germination and seed sowing trials were performed in incubators, a greenhouse and under field conditions in a forest. Finally, we disentangled correlations between the different reproductive traits of A. nemorosa along the latitudinal gradient.We found a clear positive relationship between accumulated temperature and seed and seedling traits: reproductive output of A. nemorosa improved with increasing GDH along the latitudinal gradient. Seed mass and seedling mass, for instance, increased by 9.7% and 10.4%, respectively, for every 1000 °C h increase in GDH. We also derived strong correlations between several seed and seedling traits both under field conditions and in incubators. Our results indicate that seed mass, incubator-based germination percentage (Germ%Inc) and the output of germinable seeds (product of number of seeds and Germ%Inc divided by 100) from plants grown along a latitudinal gradient (i.e. at different temperature regimes) provide valuable proxies to parameterize key population processes in models.We conclude that (1) climate warming may have a pronounced positive impact on sexual reproduction of A. nemorosa and (2) climate models forecasting plant distributions would benefit from including the temperature sensitivity of key seed traits and population processes.  相似文献   

10.
Direct observations in grasslands and cereal fields near Zurich (Switzerland) have shown that aphids constitute an essentiel component in many spiders' prey. Spiders were observed to be predators of the agricultural harmful aphidsRhopalosiphum padi L.,Sitobion avenae F.,Metopolophium dirhodum Walck.,Hyalopterus pruni Geoffr.,Myzus persicae Sulz. andAphis fabae Scop.  相似文献   

11.
Using nine microsatellite loci, we studied the effects of selective logging on genetic diversity, mating system and pollen dispersal in a population of the tree species Hymenaea courbaril, located in a 546 ha plot in the Tapajós National Forest, Pará State, Brazil. We analyzed 250 offspring (nursery reared seedlings) collected after a logging episode from 14 open-pollinated seed trees. These were compared to 367 seedlings from 20 open-pollinated seed trees previously collected from the pre-logging primary forest. The genetic diversity was significantly lower in the post-logging seed cohort. In contrast to the pre-logging population, significant levels of selfing were detected in the post-logging population (tm = 0.962, P < 0.05). However, correlated matings were reduced and the effective number of pollen donors almost doubled after harvesting (3.8 against 7.2). Logging also reduced pollen immigration into the plot (from 55% to 38%) and we found no significant correlation between the size of the pollen donors and the number of seeds fathered. Inside the plot, pollen dispersal distance was shorter before logging than after (827 and 952 m, respectively) and the reproductive pollination neighbor area (Aep) was larger (average of 178 ha). The individual and average variance effective population size within families (ranged from 1.80 to 3.21, average of 2.47) was lower than expected in panmictic populations (Ne = 4). The results indicate that while logging greatly reduced the levels of genetic diversity after logging, it also increased genetic recombination within the population and constrained crossing among related individuals. The results show that low-density tropical tree species such as H. courbaril, when harvested in moderate levels may be resilient to a reduction in the reproductive population and may maintain similar levels of outcrossing and pollen dispersal after logging.  相似文献   

12.
Pymetrozine is the first and only substance from the group of azomethine pyridines, a novel class of insecticides. The spectrum of activity covers sucking pests such as aphids, whiteflies and planthoppers. Tests were carried out in the laboratory and under field conditions to evaluate its impact on beneficial arthropods. In laboratory tests it demonstrated full selectivity against predaceous Coleoptera, Heteroptera, Neuroptera and the predatory mite Typhlodromus pyri. Following a single application at 250/200?g a.i./ha on cotton in Egypt and in the USA, the regular sampling of predators over a period of three weeks revealed a similar population development in the pymetrozine and the untreated control plots. On okra, a vegetable crop in Egypt, it suppressed populations of Aphis gossypii with two sprays at 100?g a.i./ha for the whole observation period of 23 days. It also allowed the survival of predators. These positive features make pymetrozine an ideal component in situations where sucking pests have to be controlled and natural enemies can play a substantial role as complementary control tools.  相似文献   

13.
Studies on the biology of the predaceous mite Cunaxa capreolus Berl. (Acari, Prostigmata, Cunaxidae) During life cycleCunaxa capreolus Berlese passes through egg, larva, three nymphal stages and adult. Each moving stage is proceeded by a quiescent one. Biological process such as hatching, moulting and mating were investigated. Female usually deposites its eggs singly in protected places. Number of deposited eggs per female, when fed on book lice (Psocoptera), was positively correlated with temperature. It averaged 24.6, 30.7, 40.7, and 43.5 eggs at 15°, 20°, 25° and 30 °C. Incubation period as well as duration of immature stages and adult longevity were negatively effected with temperature. The generation period (from egg to egg) ranged from 24.8 to 64.2 days when temperature changed from 30° to 15 °C. Within these limits of temperature, the simple regression indicated that an increase of 1 °C decreased the generation period for about 2.6 days.  相似文献   

14.
[目的]研究雄青斑蝶内生殖器官的形态与发育,可以为青斑蝶的人工繁殖提供理论指导。[方法]采用生殖系统解剖的方法,观察了1 12日龄青斑蝶雄成虫内生殖器官的结构组成,测定了内生殖器官的数值特征参数,并根据内生殖器官各组成部分的特征对雄性内生殖器官的发育进行了分级,以期系统了解青斑蝶雄成虫内生殖器官的形态与发育。[结果]1)雄性青斑蝶的内生殖器官包括1个精巢、2个贮精囊、1对输精管、1对复射精管、1条单射精管和附腺;2)复射精管的直径和单射精管的长度都随日龄的增大而增大;3)随着成虫日龄的增加,精巢中精子束的长度持续变长,贮精囊中的精子束长度在7日龄前快速变长且之后长度趋于稳定;4)随着日龄的增长,雄蝶精巢中精子束的数量逐渐减少,贮精囊中的精子束数量在1 7日龄时逐渐增加,之后维持稳定;复射精管中精子束数量则随着日龄的增长而逐渐增多;5)根据贮精囊和复射精管的发育特征,雄虫的内生殖器官的发育可分为:乳白透明期、精子束输送生长期、精子束大量输送成熟期、精子束补充期。[结论]雄青斑蝶内生殖器官的结构组成与其他蝴蝶相同;精子束在成虫6日龄时发育成熟,并依次释放至贮精囊、复射精管中;青斑蝶雄性内生殖器官的发育可划分为四个发育阶段。  相似文献   

15.
Hybridisation through pollen dispersal from exotic plants is increasingly recognised as a threat to the genetic integrity of native plant populations. Its genetic impact can be greater in rare taxa, due to their vulnerability to pollen swamping by more abundant congeners. We assessed the likelihood of pollen dispersal from exotic eucalypt plantations into all of Australia's rare native eucalypts, and conducted a case study of Eucalyptus perriniana, which is rare in Tasmania. The Australia-wide study involved spatial analyses of the locations for each rare species superimposed on distributions of eucalypt plantations, which were combined with known taxonomically based reproductive barriers. Of the 74 nationally listed rare eucalypt taxa, 22 had locations within 10 km of plantations of the same genus, and eight were within 1 km. These eight proximal taxa are considered priorities for monitoring. In the most extreme case, 30% of point locations originating from herbarium records and field surveys for Eucalyptus conglomerata were within 1 km of exotic plantations. In the case study, E. perriniana revealed considerable reproductive compatibility with adjacent recently established Eucalyptus nitens plantations. However, F1 hybridisation between these species was limited, with 0.2% of the 18,625 seedlings grown from 100 single-tree open-pollinated seedlots being hybrids. For now, the probability of exotic gene flow into E. perriniana appears to be low, however this probability is likely to increase as more E. nitens flowers in the surrounding landscape. These studies suggest that understanding the breeding system and biology of these populations may reveal surprising resistance to such exotic hybridisation as well as identifying high risk situations to focus conservation management.  相似文献   

16.
On the knowledge of Hyperodes bonariensis Kuschel (Col., Curculionidae) and its antagonists in Argentina Studies were made on damage ofHyperodes bonariensis as a pest of pasture plants and on incidence of its parasites and predators. Among its natural enemies,Patasson atomarius (Breth.) (Mymaridae, parasitic on eggs) appeared to be polyphagous, having a good potential rate of increase and substantical ecological tolerance and seemed to be a promising parasite.Sericophanes obscuricornis Popp. (Miridae),Nabis punctipennis Blanch. (Nabidae),Philonthus sp. (Staphylinidae) (predaceous on eggs),Pterostichus aereus (Dej.),Pt. unistriatus (Dej.),Barypus clivinoides Curt.,Cnemalobus gavi Putz.,Metius blandus (Dej.) andM. malachiticus (Dej.) (Carabidae, predaceous on adult weevils) destroyed the host to some extent, but they are not of much importance in regulating the population of this pest.  相似文献   

17.
Knowledge on reproductive phenology and pollination biology are basic elements that should be considered in the management and exploitation of plant species that offer non-timber products. The tropical tree Manilkara zapota is a species from which non-timber products have been obtained for centuries by Mayan communities in Mexico. Nevertheless, there are no quantitative reports on its reproductive biology and the factors that limit fruit production. The present study describes the reproductive phenology, breeding system and pollination of this species in two contrasting environments: medium-height, subdeciduous forest, and homegardens (“solares”) in a Mayan community in the state of Yucatan. Significant differences were found between environments both in the temporal distribution of flower and mature fruit production, as well as in the proportion of mature fruits. Homegarden trees showed the greatest fruit production, although flower production did not differ between environments. Mature fruits were of better quality (i.e., greater fresh weight) in homegardens. Hand pollination experiments showed that M. zapota is self-compatible, and that there is pollinator limitation for fruit production in trees that grow in homegardens. We propose that water and soil nutrients are the main factors limiting M. zapota fruit production in forests, while in homegardens the main factor appears to be pollinator availability.  相似文献   

18.
The predatory mite Typhlodromus pyri Scheuten (Acari, Phytoseiidae) has been reported as an important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture and vineyards at below 25?°C. However, sufficient biological data was lacking on its efficiency at temperatures above 25?°C. Therefore, the purpose of the present laboratory work was to obtain experimental data on prey consumption during development as well as longevity and reproduction of T. pyri on apple leaf discs and in Plexiglas cells at constant temperatures of 25?±?2?°C and 30?±?2?°C with P. ulmi as prey.  相似文献   

19.
Larvae of the common green lacewing, Chrysoperla carnea (Stephens) (Neuroptera :Chrysopidae) were fed with different densities of Hyalopterus pruni (Geoffer) (Homoptera: Aphididae) in Petri dishes under laboratory conditions. Functional response, developmental time, mortality rate and fecundity of the predator were measured. Treatments were carried out at 25±1°C, 65±5% RH and a 16L:8D photoperiod in a controlled temperature cabinet. Prey was given at densities of 5, 10, 20, 40, 80, 160 and 250 aphids per larva per day and the number of consumed prey, developmental time and mortality rate of the predator were recorded daily. Larvae of C. carnea responded to increasing prey densities with increasing food consumption and older larval stages displayed a higher rate of predation than younger ones. The behaviour of each of the three larval stages matched Hollings type II functional response. Larvae were able to complete their development in each of the seven prey densities, although increased prey densities reduced developmental time and mortality rate. Increased prey consumption in immature stages resulted in a higher net reproduction rate (R 0) and the intrinsic rate of increase (r m) of adult females.  相似文献   

20.
Great Smoky Mountains National Park is using systemic imidacloprid to treat eastern hemlocks (Tsuga canadensis [L.] Carr.) infested with the exotic insect, hemlock woolly adelgid (Adelges tsugae Annand). This study investigated effects of these treatments on insectivorous birds and hemlock canopy arthropod assemblages in the context of food availability for insectivorous birds. Six pairs of treated and untreated hemlock sites were studied in 2007. Territories of three hemlock-associated Neotropical migratory foliage-gleaning bird species were mapped in these six sites, and relationships between bird territory density and hemlock foliar density were examined. Canopy arthropods were sampled by clipping mid-canopy hemlock branches in each paired site. Arthropods were identified to order or suborder and categorized into bird prey guilds and non-target herbivorous insect guilds. Despite being treated within the previous two years, there were no differences in hemlock woolly adelgid infestation between treated and untreated sites. This may reflect recovery or because the imidacloprid is slow-acting. Bird densities also did not differ between treated and untreated sites but were positively related to branch foliage mass, implying a preference in these birds for well-foliated hemlocks. A total of 10,219 hemlock woolly adelgids, and a total of 906 other arthropods from 16 orders were collected. There were no differences in species richness, abundance, or species composition between treated and untreated sites for total arthropods, or for immature arthropods ≥ 3 mm. In contrast, non-target herbivorous Hemiptera and larval Lepidoptera were significantly reduced in treated hemlocks. Although larval Lepidoptera are primary prey for insectivorous foliage-gleaning birds, the similarity in bird densities between treated and untreated sites suggests the birds are able to find other food resources in the mixed hemlock-deciduous stands where the study sites were located. Therefore, controlling hemlock woolly adelgid-induced defoliation through use of imidacloprid may have short-term benefits for hemlock-associated birds. While imidacloprid treatments did not appear to be currently affecting most arthropods, primary prey guilds should be monitored for long-term declines that could impact hemlock-associated birds.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号