Responses to olfactory and visual cues by over-wintered and summer generations of the pollen beetle, Meligethes aeneus

Abstract.  Behavioural responses to odours of oilseed rape in bud and flower stage and to green and yellow colours are studied for the two main phenological stages of pollen beetles, Meligethes aeneus , a major pest of oilseed rape, Brassica napus . Over-wintered individuals oviposit in buds of oilseed rape. Adults of the new generation (i.e. the summer generation) feed on flowers of different plant species before over wintering. In olfactometer experiments, the over-wintered beetles display a higher preference for odour of oilseed rape at the bud stage compared with the summer generation, both with and without colour stimuli. Flower odours are preferred in combination with yellow colour. Colour stimuli presented alone do not affect the behaviour. The summer generation beetles respond to both bud and flower odour. Adding colour stimuli changes the summer generations preference towards yellow and flower odour.     

重复遭遇战对雌性黑线仓鼠生理状态的影响

以独居型啮齿动物——黑线仓鼠(Cricetulus barabensis)为对象,主要测定了与优势-从属关系有关的体重、生理状态和粪便激素变化规律相关的参数。野生成年仓鼠捕获于鲁西南山区农田并于实验室内单独饲养。按照陌生和体重匹配的原则配对,实验动物在中立竞技场中每天进行15 m in的遭遇战并收集粪便,连续28 d。以攻击行为、防御行为、社会行为、非社会行为确定个体的优势-从属地位。用于实验的动物共33只。行为实验结束后,将动物解剖,确定其繁殖及生理状态。结果表明:4周重复遭遇战期间,(1)优势雌体体重显著增加;(2)肾上腺指数显著降低;(3)雌体肾上腺指数与卵巢指数无显著的相关关系;(4)雌体粪便皮质醇及雌二醇含量随时间表现出明显的波动,但优势与从属个体间差异不显著;(5)优势雌体的粪便雌二醇含量与皮质醇含量呈显著的正相关关系。研究结果提示,重复遭遇战未影响雌体的存活及潜在繁殖能力,这可能与黑线仓鼠的独居生活方式有关。     

Olfactory responses of Aphidius gifuensis to odors of host plants and aphid‐plant complexes

Abstract The olfactory responses of Aphidius gifuensis to odors from two host plants (Nicotiana tabacum and Brassica napus ssp.) and their complexes with different infestation levels of two host aphids (Myzus persicae and Lipaphis erysimi) were respectively examined in an olfactometer. The results showed that female A. gifuensis did not respond to odors of undamaged or mechanically damaged host plants, but significantly responded to odors of aphid/plant complexes. Moreover, A. gifuensis responded significantly to odors of both M. persicae and L. erysimi/plant complexes when host plants were infested by high levels of aphids, suggesting that quantity of aphid‐induced volatiles could be important for attracting A. gifuensis. When tested between aphid/plant complexes, A. gifuensis did not show its preference for either complex. The efficiency of A. gifuensis against aphids in open fields potentially could be improved by using its olfactory response to aphid/plant complexes.     

Relevance of visual and olfactory cues for host location in the mustard leaf beetle Phaedon cochleariae

The relevance of visual and olfactory cues for host‐plant location is investigated in males and females of the oligophagous mustard leaf beetle Phaedon cochleariae Fabricius (Coleoptera: Chrysomelidae). Different objects are offered in a walking arena and the behaviour of beetles is observed. Beetles orient toward vertically or horizontally striped black and white pattern independent of stripe orientation. The results suggest that contrast facilitates orientation in the field, whereas the pattern itself may be less important for host location in dense vegetation. The response to green and yellow objects is tested to investigate discrimination abilities between young (green) and mature (yellow) leaves. Beetles prefer green over yellow independent of material (cardboard or leaves of Nasturtium officinale R. Br., Brassicaceae). Preference behaviour tested in a dual‐choice contact assay coincides with visual preferences, where adults prefer young, more nutritious leaves for feeding and oviposition. Furthermore, females discriminate between visual cues of green leaves and green cardboard, whereas males do not, indicating that females are more sensitive in colour discrimination. Differences in colour wavelength influence the choice of beetle behaviour more strongly than differences in intensity. Both sexes of P. cochleariae prefer volatiles of the host plant N. officinale, whereas only females respond to the main volatile compound 2‐phenylethyl isothiocyanate. Given a choice between visual and olfactory cues, males orientate towards the colour cues, whereas females do not show any preferences. In males, visual cues may thus override olfactory cues, whereas, in females, both are equally important, which may reflect different ecological requirements and/or physiological abilities.     

Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth

Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state.     

Shifting effects of physiological integration on performance of a clonal plant during submergence and de-submergence

Background and Aims

Submergence and de-submergence are common phenomena encountered by riparian plants due to water level fluctuations, but little is known about the role of physiological integration in clonal plants (resource sharing between interconnected ramets) in their adaptation to such events. Using Alternanthera philoxeroides (alligator weed) as an example, this study tested the hypotheses that physiological integration will improve growth and photosynthetic capacity of submerged ramets during submergence and will promote their recovery following de-submergence.

Methods

Connected clones of A. philoxeroides, each consisting of two ramet systems and a stolon internode connecting them, were grown under control (both ramet systems untreated), half-submerged (one ramet system submerged and the other not submerged), fully submerged (both ramet systems submerged), half-shaded (one ramet system shaded and the other not shaded) and full-shaded (both ramet systems shaded) conditions for 30 d and then de-submerged/de-shaded for 20 d. The submerged plants were also shaded to very low light intensities, mimicking typical conditions in turbid floodwater.

Key Results

After 30 d of submergence, connections between submerged and non-submerged ramets significantly increased growth and carbohydrate accumulation of the submerged ramets, but decreased the growth of the non-submerged ramets. After 20 d of de-submergence, connections did not significantly affect the growth of either de-submerged or non-submerged ramets, but de-submerged ramets had high soluble sugar concentrations, suggesting high metabolic activities. The shift from significant effects of integration on both submerged and non-submerged ramets during the submergence period to little effect during the de-submergence period was due to the quick recovery of growth and photosynthesis. The effects of physiological integration were not found to be any stronger under submergence/de-submergence than under shading/de-shading.

Conclusions

The results indicate that it is not just the beneficial effects of physiological integration that are crucial to the survival of riparian clonal plants during periods of submergence, but also the ability to recover growth and photosynthesis rapidly after de-submergence, which thus allows them to spread.     

Evolution of larval host plant associations and adaptive radiation in pierid butterflies

Butterflies in the family Pieridae (Lepidoptera: Papilionoidea) feed as larvae on plants belonging primarily to three distantly related angiosperm orders: Fabales (legumes and allied plants), Brassicales (crucifers and related plants containing mustard oil glucosides), and Santalales ('mistletoes'). However, some utilize plants from 13 other families in a further eight orders. We investigated the evolutionary history of host plant use of the Pieridae in the context of a recent phylogenetic hypothesis of the family, using simple character optimization. Although there is a close association between host plant and butterfly higher classification, we find no evidence for cospeciation but a pattern of repeated colonization and specialization. The ancestral host of the family appears to be Fabaceae or Fabales, with multiple independent shifts to other orders, including three to Santalales. The shift to Brassicales, which contain secondary compounds (glucosinolates), promoted diversification and adaptive radiation within the subfamily Pierinae. Subsequent shifts from crucifers to mistletoes (aerial-stem hemiparasites) facilitated further diversification, and more recent shifts from mistletoes to mistletoe host trees led to exploitation of novel host plants outside the conventional three orders. Possible mechanisms underlying these host shifts are briefly discussed. In the Pierinae, a striking association between host plant, larval and adult behaviour, adult phenotype, and mimicry calls for further research into possible relationships between host specialization, plant chemistry and butterfly palatability.     

淹水胁迫对青杨雌雄幼苗生理特性和生长的影响

为揭示青杨(Populus cathayana)雌雄幼苗对淹水胁迫的适应性, 在实验地内通过土培盆栽淹水方式从植株生理生态和生长发育方面探讨淹水胁迫对青杨扦插苗的影响。试验分为对照和淹水2个处理, 处理时间为40天。结果显示: (1)淹水胁迫导致青杨幼苗叶片中的丙二醛(MDA)含量和茎部淹水区的不定根数显著升高, 植株的净光合速率(P_n)、叶绿素含量、超氧化物歧化酶(SOD)活性、株高、基径、总叶面积、比叶面积(SLA)、根生物量、叶生物量、茎生物量、总生物量干重和根冠比(R/S)显著降低。(2)与雄株相比, 淹水胁迫显著增加了雌株幼苗的MDA含量, 降低了SOD活性、P_n、类胡萝卜素(Caro)含量、叶绿素a/b、SLA、根生物量和R/S, 并导致雄株在淹水胁迫下具有比雌株更高的气孔导度(G_s)、胞间CO₂浓度(C_i)、蒸腾速率(T_r)、不定根数和株高。可见, 淹水胁迫对青杨雌雄幼苗的形态生长和生理过程均有严重的抑制作用, 但表现出显著的性别间差异。雄株可以通过维持更高的光合作用能力和增加不定根数量来维持植株的生长, 从而表现出比雌株更强的抗逆性。     

Innate olfactory responses of female and male parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) toward host plant infested by the cucumber moth Diaphania indica Saunders (Lepidoptera: Crambidae)

The behavioural responses of Apanteles taragamae, a larval parasitoid of the cucumber moth Diaphania indica, to the volatiles of cucumber plants was investigated in a four-arm olfactometer. Females and males were given a choice between several odour sources that included (1) clean air, (2) uninfested, (3) host-infested, and (4) mechanically damaged cucumber plants. Females and males showed different preferences for volatiles emanating from these plants. Females responded significantly longer to the volatiles from uninfested plants than clean air, and to host-infested plants than uninfested plants. There were no significant differences in female responses to the volatiles from mechanically damaged and uninfested plants. Males responded significantly longer to clean air rather than uninfested plants. The volatiles from both uninfested and host-infested cucumber plants may play important roles in host habitat location of A. taragamae females.     

Effect of mineral oils on host plant selection and probing behavior of Rhopalosiphum padi

Aphids that colonize and reproduce on potato are some of the most efficient vectors of Potato virus Y (PVY) (Potyviridae: Potyvirus), and hence these aphids have been the focus of the majority of studies to date. However, other non‐colonizing aphids can also function as vectors. Mineral oil is the only product available to growers that effectively prevents the spread of PVY in potato seed production. Most previous studies focused on the effect of mineral oil on the behavior of aphids on their preferential host plant, and consequently there is a lack of information for non‐colonizing aphids on potato plants. The objective of this study was to determine the effect of spraying potatoes with one of two mineral oils, Superior 70 or Vazyl‐Y, on host selection and probing behavior of the non‐colonizing aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae). The electrical penetration graph (EPG) technique, combined with ethological observations, determined that there was no difference in R. padi behavior on potato plants treated with Superior 70. However, there were few significant changes in R. padi behavior on plants sprayed with Vazyl‐Y, including a delay in the initiation of stylet penetration and an increase in the duration of xylem sap ingestion. These new data support previous results and confirm that the mode of action of mineral oil in the reduction of the spread of PVY is not solely due to the modification of the behavior of aphids.     

Effect of plant nitrogen and water status on the foraging behavior and fitness of an omnivorous arthropod

Omnivorous arthropods make dietary choices according to the environment in which they forage, mainly availability/quality of plant and/or prey resources. Such decisions and their subsequent impacts on life‐history traits may be affected by the availability of nutrients and water to plants, that is, through bottom‐up forces. By setting up arenas for feeding behavior observation as well as glasshouse cages for plant preference assessment, we studied effects of the presence of prey (Lepidoptera eggs) and nitrogen/water availability to host tomato plants on the foraging behavior and life‐history traits in the omnivorous predator Macrolophus pygmaeus (Heteroptera: Miridae). In the absence of prey, the predator fed equally on the plants treated with various levels of nitrogen and water. In the presence of prey, however, the feeding rate on plants decreased when the plant received low water input. The feeding rate on prey was positively correlated with feeding rate on plants; that is, prey feeding increased with plant feeding when the plants received high water input. Moreover, plants receiving high water input attracted more M. pygmaeus adults compared with those receiving low water input. For M. pygmaeus fitness, the presence of prey enhanced its fertility and longevity, but the longevity decreased when plants received low compared with high water input. In conclusion, the omnivorous predator may be obliged to feed on plants to obtain water, and plant water status may be a limiting factor for the foraging behavior and fitness of the omnivorous predator.     

Effect of time of day on soccer specific skills in children: psychological and physiological responses

The aim of this study was to examine the effect of time of day on soccer-specific skills and physiological and psychological parameters in children. Ten male children soccer players (age: 14.6?±?0.8 years; height: 1.63?±?0.4 m; body mass: 52.5?±?4.9 kg) performed two shooting accuracy tests before and after a 10?×?20-m dribbling sprint test with 20-s of passive recovery between repetitions. The measurements were taken at 08:00 h, 13:00 h, and 17:00 h in a randomized order. Mean heart rate (HR) was monitored during the dribbling test. At the beginning of each test session, blood pressure and intra-aural temperature were measured. Likewise, children were asked to complete the profile of mood state (POMS) and the Hooper Index questionnaires. Lactate concentration ([La]) was recorded at rest, post-fifth recovery periods and post-second accuracy test. Moreover, they indicate their rating of perceived exertion (RPE) score immediately at the end of each test session. The results of this study showed that dribbling performance was higher at 13:00 h and 17:00 h in comparison with 08:00 h (p?p?r?=?0.6, p?相似文献   

Oviposition and feeding behaviour by the vine weevil Otiorhynchus sulcatus on red raspberry: effects of cultivars and plant nutritional status

• 1 The vine weevil Otiorhynchus sulcatus is a major pest of horticultural crops worldwide, with root‐feeding larvae causing most damage. Adult oviposition aboveground may therefore influence levels of damage as the larvae are relatively immobile after oviposition.
• 2 The present study investigated feeding and oviposition behaviour on red raspberry Rubus idaeus using intact plants, ensuring that choices reflected the realistic differences in cultivar appearance and chemical composition. Previous studies investigating vine weevil feeding and oviposition on other crops have used excised plant material, which may inadvertently influence behaviour.
• 3 Adult weevils significantly preferred to feed on particular cultivars in the choice experiment (e.g. Tulameen), although they consumed significantly more foliage (0.22–1.03 cm²/day) on different raspberry cultivars (e.g. Glen Moy, Glen Rosa and a wild accession) in no‐choice situations.
• 4 In choice experiments, weevils tended to avoid laying eggs on some cultivars (e.g. Glen Moy and the wild accession). The number of eggs laid (1.91–4.32 eggs per day) did not, however, differ significantly between the cultivars in a no‐choice situation. Foliar nitrogen and magnesium concentrations were positively, although weakly, correlated with the total number of eggs laid.
• 5 The present study highlights the importance of considering both choice and no‐choice tests when assessing crop susceptibility to attack because weevils may avoid feeding on certain cultivars (e.g. Glen Moy) when given a choice, although this would cause significant damage to such cultivars if they were grown in monoculture (i.e. when there is no alternative).

     

Influence of celestial light on visual and olfactory behavior of seed chalcids (Hymenoptera: Eurytomidae)

When the alfalfa [Bruchophagus roddi (Gussakovsky)], clover [Bruchophagus gibbus (Boheman)], and trefoil seed chaldds (TSC) [Bruchophagus platypterus (Walker)] were exposed to yellow, white, green, and purple painted polyethylene vials perforated by four small holes, only the latter species had a color preference, and that was for yellow, the color of its host flower. When TSC were exposed to green and yellow targets 5 h after sunrise, they preferred yellow targets but not 1 h after sunrise. The possibility of a circadian response was eliminated because different sequences of light-dark regimes prior to the test did not change the results. When TSC were exposed only to yellow targets, half of which had trefoil flowers hidden within, females preferred targets with flowers. When an identical test was conducted but with green instead of yellow targets, the preference for targets with flowers disappeared. In a four-choice test, TSC preferred yellow targets with or without flowers to green targets with or without flowers. Thus, TSC displayed an olfactory response only when the color yellow was present. In unfiltered skylight females preferred baited targets when the test began 3 h before or 1 h after solar noon but not 4 h before or 2 h after solar noon. Chalcids did display an olfactory preference 4 h before solar noon when a Polaroid filter was used to filter skylight and provide an east-west but not a north-south E-vector. When Helmholtz coils were used to apply a magnetic field that canceled or changed the direction of the earth's magnetic field, olfactory preference disappeared because the applied magnetic field changed TSC perception of the E-vector. In effect, TSC must perceive yellow in the presence of an east-west E-vector to display an olfactory preference to a choice of odors. We believe this is the first report that the E-vector of celestial light can influence olfactory and visual behavior of an insect.     

The effects of sex steroids and vasotocin on behavioral responses to visual and olfactory sexual stimuli in ovariectomized female roughskin newts

Previous studies have found that vasotocin (AVT) administration to male roughskin newts (Taricha granulosa) enhances courtship clasping as well as appetitive responses to specific sexual stimuli and that treating female newts with androgens plus AVT induces the expression of male-typical courtship clasping (the selective clasping of females). However, the unique and/or interactive effects of sex steroids and AVT on appetitive responses to specific sexual stimuli have not yet been determined. To first identify male-typical, sexually dimorphic appetitive responses to female sexual stimuli, we tested intact newts during the breeding season and found that males, but not females, are attracted to female visual and pheromonal sexual stimuli. We then used ovariectomized (ovx) females implanted with empty silastic capsules (Blk) or with capsules containing testosterone (T), dihydrotestosterone (DHT), or estradiol (E2) and then injected with either saline or AVT to determine the effects of steroids and AVT, alone or in combination with each other, on male-typical behavioral responses to those stimuli. E2 treatment depressed responses toward female visual stimuli independently of AVT. On the other hand, only T-implanted, AVT-injected females displayed male-typical behavioral responses toward female olfactory stimuli, preferring to spend more time in proximity to female-scented than unscented newt models and selectively clasping the female-scented models. Together, these results support the conclusion that sex steroids and AVT influence behavioral responses to sexual stimuli via sensory-specific mechanisms. Furthermore, they suggest that T and AVT interact within the brain to influence sensorimotor processing in the pathways that integrate olfactory sexual stimuli into male-typical courtship behaviors.     

Larval survival,host plant preferences and developmental responses of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) on wild brassicaceous species

The diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important pest of cultivated brassicaceous crops worldwide. The host plant preferences, developmental biology and survival and longevity of P. xylostella are relatively well understood on commercial crop species; however, its relationship with brassicaceous weeds is poorly known. Sinapis arvensis L., Erysimum cheiranthoides L. and Capsella bursa‐pastoris (L.) Medicus are among the most common brassicaceous weeds worldwide and can serve as important bridge hosts of P. xylostella. In this study, preference and performance of P. xylostella were compared on these weed species. In free‐choice situations, females deposited 5.5 and 18.8 times more eggs on S. arvensis than on E. cheiranthoides and C. bursa‐pastoris, respectively. Survival from neonate to pupa and from pupa to adult was highest on S. arvensis and E. cheiranthoides and lowest on C. bursa‐pastoris. Development was fastest, foliage consumption was greatest, pupae and silk cocoons were heaviest, adult body masses and longevities were highest and forewings were largest for both females and males when reared as larvae on S. arvensis. Realized fecundity of new generation adults was highest for individuals reared on S. arvensis compared to those reared on E. cheiranthoides or C. bursa‐pastoris. Relative growth rates of pupae and adults were highest on S. arvensis, suggesting that this plant species is a high‐quality host for P. xylostella compared with other species tested. Potential impacts of these wild brassicaceous species on P. xylostella populations are discussed.     

Host‐searching responses to herbivory‐associated chemical information and patch use depend on mating status of female solitary parasitoid wasps

1. In a tritrophic interaction system consisting of plants, herbivores, and their parasitoids, chemicals released from plants after herbivory are known to play important roles for many female parasitoids to find their hosts efficiently. On the plant side, chemical information associated with herbivory can act as an indirect defence by attracting the natural enemies of the host herbivores. 2. However, mated and virgin females of haplodiploid parasitoids might not necessarily respond to such chemical cues in the same way. Since virgin females can produce only sons, they might refrain from searching for hosts to invest eggs until copulation, in order to produce both sexes. 3. Here, we investigated differential host‐searching behaviours shown by mated and virgin females in the solitary parasitoid wasp, Cotesia vestalis, in response to herbivory‐associated chemical information from cruciferous plants infested by their host larvae, Plutella xylostella. 4. Mated females showed a significantly higher flight preference for host‐infested plants over intact plants, while no preference was observed with virgin females. Mated females also showed more intensive antennal searching and ovipositor probing behaviours to leaf squares with wounds caused by hosts than did virgin females. Furthermore, mated females stayed longer in host patches with higher parasitism rates than virgin females. 5. These results indicate that mating status of C. vestalis females clearly influences their host‐searching behaviour in response to herbivory‐associated chemical information and patch exploitation. Female parasitoids seem to forage for hosts depending on their own physiological condition in a tritrophic system.     

The effects of physiological factors and host plant experience on the ovipositional activity of the sweet potato whitefly, Bemisia tabaci

Both egg load and levels of vitellogenin and vitellin increased when Bemisia tabaci Gennadius (Homoptera: Aleyrodidae), were deprived of host plants. These increases resulted in significant increases in rates of oviposition. There was no difference in total fecundity between whiteflies temporarily deprived of hosts and a control treatment that had continuous access to hosts. The results of previous exposure to a preferred host, melon (Cucumis melo), and a non-preferred host, cotton (Gossypium hirsutum), were also examined. B. tabaci deposited significantly more eggs during a 6-h period on melon than on cotton, regardless of host species they were previously confined to. In addition, whiteflies previously exposed to cotton, deposited more eggs than females previously exposed to melon. This higher rate of oviposition resulted in a low egg load as well as lower levels of vitellogenin and vitellin. Conversely, a low rate of oviposition led to high egg load and high levels of vitellogenin and vitellin. Individuals from the same treatment exhibited variation in egg load, which was negatively and significantly correlated with previous oviposition activity. We conclude that the effects of previous host plant exposure on oviposition were, in part, due to behavioral differences that are not related to the reproductive physiology.