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1.
Only winged male and female ants generally mate through nuptial flight during the reproductive season. In the ants of Cardiocondyla, the males show wing dimorphism and their reproductive strategies differ depending on the differences in wing morphology. It has been suggested that wingless “ergatoid” males bearing very similar external morphologies to workers mate within natal nests, whereas winged males bearing typical ant male morphology disperse from their nests to mate. However, some behavioral observations suggest that the winged males of some Cardiocondyla ants such as C. obscurior and C. minutior may mate within natal nests before dispersion. We evaluated the factors affecting the mating behaviors of the winged males of C. minutior under laboratory conditions. We found that (1) the winged males remained and mated with virgin females in natal nests when either virgin winged females or the relatively mature pupae of winged females (i.e., at least 10 days) were present in the nest, (2) the winged males dispersed to adjacent nests with virgin winged females when only mated queens and the relatively young pupae of winged females (i.e., <9 days) were present in the nest, and (3) all winged males were accepted by the workers of non-natal nests irrespective of the distance from the natal nests in the field. Although most ergatoid males were accepted by the workers of close non-natal nests, they were all attacked and killed by the workers of distant non-natal nests. These results suggest that intra-nest mating and the dispersion of the winged males of C. minutior are facultatively determined by the condition of winged females (virginity and relative pupal age) in natal nests. Furthermore, our results suggest that winged males are likely to seek mating partners chemically and to mate with virgin winged females.  相似文献   

2.
Tuberculatus quercicola (Matsumura) feeds on Quercus dentata Thunberg, and has mutualistic interactions with ants. Tuberculatus quercicola has two winged morphs in its life cycle, winged females appear in summer and sexual males appear in autumn. Previous studies have shown that wing loading (ratio of body volume to wing area) is higher for the winged females, because of ant attendance, resulting in extremely low dispersal. It is known that the nutritional quality of host plants is high in spring and autumn, when leaves are growing or senescent, and low in summer when leaves are mature. This study examined the effects of seasonal plant deterioration on the development of flight apparatus (wing size and flight muscle) of winged females and males. Moreover, field intercept traps were used to examine the extent of dispersal of males. The results showed that seasonal plant deterioration affected development of the flight apparatus of winged females, particularly flight muscle. Flight muscle development was significantly higher in winged males in autumn than in winged females. However, winged males were not caught in any of the traps. The different resource allocation to the flight apparatus of winged females and males is discussed.  相似文献   

3.
Sequential deletions of the promoter region of the WCI-3b gene, which encodes the major chymotrypsin inhibitor of winged bean, were constructed and their expression was analyzed in transgenic tobacco plants and in bombarded winged bean seeds. In transgenic tobacco plants, a critical promoter region which is important for high levels of expression in seeds was identified, but deletion of this region had essentially no effect when bombarded into winged bean seeds.  相似文献   

4.
A short‐winged morph was recently discovered in the migratory locust, Locusta migratoria. It is different from the normal, long‐winged morph not only in forewing length but also in hind femur length, displaying a dimorphism. To understand the significance of this dimorphism, other morphological characters were compared between the two morphs, and the time of differentiation of wing‐pad length was investigated. Wing weights were heavier in the long‐winged morph than in the short‐winged morph. This result showed that the short‐winged morph is not formed by a failure of wing expansion. No obvious morph‐specific differences were observed in wing venation, but wing allometry studies indicated that the distal areas of the fore‐ and hindwings were disproportionally reduced in the short‐winged morph compared to the long‐winged morph. The morphological differentiation of the wing pad between the two morphs was observed at the penultimate nymphal stage. The flight muscle was well developed in the two morphs, and no sign of flight muscle histolysis was detected in either morph after adult emergence. An analysis of adult body dimensions suggested that the density‐dependent phase shifts known for the long‐winged morph of this locust were also exhibited by the short‐winged morph, demonstrating that these shifts are not specific to the migratory long‐winged morph.  相似文献   

5.
The oriental mole cricket Gryllotalpa orientalis exhibits variation in wing dimorphism. In an Okinawa population, no short‐winged individuals were observed, and wing dimorphism has not been detected. Flight behavior of G. orientalis was observed from April to October in Okinawa. In contrast, a Hyogo population exhibited seasonal wing dimorphism and long‐winged individuals appear from June to September. The flight period of the long‐winged morph coincided with this period. Short‐winged individuals appeared from September to the following June and they never fly. Both populations showed univoltine life cycles. Considering the possible flight period, wing pattern and life cycle of mole crickets in these two areas, it is presumed that flightlessness is expected to arise when adults can not experience suitable temperatures for flight activity.  相似文献   

6.
Sex ratio biases in avian species remain controversial, although several studies have documented apparent facultative adjustment of offspring sex ratios. While hybridizing pied and collared flycatchers have exhibited sex ratio skews that may be a response to sex‐based costs associated with hybridization, this appears not to be true of a hybridized population of blue‐winged Vermivora pinus and golden‐winged V. chrysoptera warblers. We examined the primary sex ratio of nestlings in a population of hybrid and introgressed golden‐winged warblers. The sex ratio of 298 nestlings from 81 nests in the population was approximately 50:50. We conducted paternity assignments and analyzed groups of nestlings with shared genetic parents (“genetic broods”) and found no difference from the expected binomial distribution, and no statistically significant relationship between parental species phenotype and nestling sex ratio. We saw no evidence of preferential production of male or female nestlings, and female hybrids were found to mate and breed in the population. This suggests that heterogametic (female) hybrids are both viable and fertile, and thus that Haldane's Rule does not apply to this system. While populations of hybridizing golden‐winged warblers should be monitored for evidence of costs of heterospecific pairings, it is unlikely that adjustment of sex ratios would be the form of compensation for sub‐optimal mating conditions. Our results provide support for the emerging hypothesis that hybrids suffer no disadvantage relative to golden‐winged and blue‐winged warblers.  相似文献   

7.
The biological effects of raw winged bean seeds were investigated with feeding experiments on rats, and the effects of lectin (phytohemagglutinin) present in the seeds are discussed. Administration of a 30% raw winged bean diet caused strong growth depression in young rats, and led to death within 10 ~ 20 days, inducing severe damage to the small intestine of the rats. Significant morphological changes of the intestinal mucosa were observed with a microscopic investigation. As the lethal effect was eliminated by autoclaving but not removed with supplementation of 0.5% l-methionine to the raw winged bean diet, the lectin was assumed to be closely related to the deleterious effects of raw winged bean. In vitro and in vivo digestion tests of the lectin revealed that the winged bean lectin had resistance to peptic, pancreatic and membrane digestions. The hemagglutinating activity was also detected in the intestinal mucosa and faeces from rats ingesting the raw winged bean or its purified lectin. The binding action of lection to mucosal epitheliums of the gastrointestinal tract is suggested to be the initial step of the deleterious effects induced by the winged bean lectin.  相似文献   

8.
Aphids (Homoptera: Aphidoidea) produce a number of different phenotypes in their life-cycle, among which are winged (alate) and wingless (apterous) morphs. Lowe & Taylor (1964) and Sutherland (1969a, b) were the first to suggest that aphid clones differ in their propensity to produce the winged morph and that in the pea aphid (Acyrthosiphon pisum Harris), this propensity is linked to the colour of the phenotype. We tested for the occurrence of genetic variation in winged morph production by rearing individuals from red and green clones of pea aphid under wing-inducing (crowding) and control conditions, and scored the phenotypes of their offspring. Clones differed significantly in alate production and red clones produced on average a higher proportion of winged morphs than green clones. Importantly, however, there was considerable variation between clones of the same colour. Broad-sense heritabilities of winged morph production were 0.69 (crowding treatment) and 0.63 (control). Clones also differed in the number of offspring they produced. When exposed to the crowding stimulus, aphids deferred offspring production, resulting in a higher number of offspring produced in the crowding treatment than in the control.  相似文献   

9.
Several species ofCardiocondyla ants have dimorphic males: wingless (ergatoid) and winged (alate) males, while otherCardiocondyla species includingC. nuda have only wingless males. We made an evolutionarily stable strategy model for explaning the male polymorphism and the ratios of wingless males in the genusCardiocondyla. Wingless males emerge earlier than winged males in each reproductive season. Females (F 1) which have emerged before winged males copulate only with wingless males, and females (F 2) which emerge after winged males copulate with both wingless and winged males. Wingless males have a lower copulation ability (b n) than winged males (b w). The reproductive success of females which copulate at the early stage (v 1) is assumed to be larger than that of females which copulate at the late stage (v 2). The model predicts that there are 3 different evolutionarily stable states: 2 monomorphic states of wingless and winged males, and a dimorphism of the 2 types of males. In the dimorphic state, the rate of wingless males increases as the survival rate of wingless males (s) increases,v 1/v 2 increases,F 1/F 2 increases andb n/b w increases. For dimorphism to exist,s b n/b w<1 must be satisfied, and this condition corresponds to the value of observed data. The value ofv 1/v 2 would be difficult to be obtained by actual data, but we can estimate this value with the model.  相似文献   

10.
The White‐winged Flufftail (Sarothrura ayresi) is known to occur in the highland marshes of Ethiopia, as well as almost 4000 km in South Africa. The White‐winged Flufftail is listed globally as Critically Endangered. In South Africa the population is estimated to be <50 birds. These birds are severely threatened by habitat destruction. Thus far, no genetic studies have been conducted on S. ayresi to confirm genetic connectivity between the South African and Ethiopian populations. In this study, analysis of mitochondrial and nuclear markers was conducted for White‐winged Flufftail samples from South African and Ethiopian birds, as well as Red‐chested Flufftail (Sarothrura rufa) for species comparison. Analyses of the DNA regions identified three variations between the two populations, supporting the hypothesis that these two populations are not different species or subspecies but are rather one migrating population with different seasonal occupied ranges. However, these results do not exclude the possibility of additional breeding and nonbreeding sites. Low genetic diversity in the populations of White‐winged Flufftails was observed, which needs to be further elucidated with fast evolving co‐dominant markers such as microsatellites, as this low diversity may ultimately contribute to the extinction of the species.  相似文献   

11.
Detailed knowledge of migratory connectivity can facilitate effective conservation of Neotropical migrants by helping biologists understand where and when populations may be most limited. We studied the migratory behavior and non‐breeding distribution of two closely related species of conservation concern, the Golden‐winged Warbler (Vermivora chrysoptera) and Blue‐winged Warbler (Vermivora cyanoptera). Although both species have undergone dynamic range shifts and population changes attributed to habitat loss and social interactions promoting competition and hybridization, full life‐cycle conservation planning has been limited by a lack of information about their non‐breeding ecology. Because recent work has demonstrated that the two species are nearly identical genetically, we predicted that individuals from a single breeding population would have similar migratory timing and overwintering locations. In 2015, we placed light‐level geolocators on 25 males of both species and hybrids in an area of breeding sympatry at the Fort Drum Military Installation in Jefferson and Lewis counties, New York. Despite extreme genetic similarity, non‐breeding locations and duration of migration differed among genotypes. Golden‐winged Warblers (N = 2) overwintered > 1900 km southeast of the nearest Blue‐winged Warbler (N = 3) and spent nearly twice as many days in migration; hybrids (N = 2) had intermediate wintering distributions and migratory timing. Spring migration departure dates were staggered based on distance from the breeding area, and all birds arrived at the breeding site within 8 days of each other. Our results show that Golden‐winged Warblers and Blue‐winged Warblers in our study area retain species‐specific non‐breeding locations despite extreme genetic similarity, and suggest that non‐breeding locations and migratory timing vary along a genetic gradient. If the migratory period is limiting for these species, our results also suggest that Golden‐winged Warblers in our study population may be more vulnerable to population decline than Blue‐winged Warblers because they spend almost twice as many days migrating.  相似文献   

12.
Summary Only legumes of the cowpea cross-inoculation group, including the winged bean (Psophocarpus tetragonolobus) were found to form nodules in a temperate zone soil with no previous history of legume cropping. Isolates from root nodules from uninoculated winged beans grown in the field only nodulated legumes in the cowpea cross-inoculation group.Rhizobium japonicum formed ineffective nodules with the winged bean. Contribution No.5852, Scientific Article No.A2802 of the Maryland Agricultural Experiment Station, Department of Botany.  相似文献   

13.
In animals, inducible morphological defences against natural enemies mostly involve structures that are protective or make the individual invulnerable to future attack. In the majority of such examples, predators are the selecting agent while examples involving parasites are much less common. Aphids produce a winged dispersal morph under adverse conditions, such as crowding or poor plant quality. It has recently been demonstrated that pea aphids, Acyrthosiphon pisum, also produce winged offspring when exposed to predatory ladybirds, the first example of an enemy‐induced morphological change facilitating dispersal. We examined the response of A. pisum to another important natural enemy, the parasitoid Aphidius ervi, in two sets of experiments. In the first set of experiments, two aphid clones both produced the highest proportion of winged offspring when exposed as colonies on plants to parasitoid females. In all cases, aphids exposed to male parasitoids produced a higher mean proportion of winged offspring than controls, but not significantly so. Aphid disturbance by parasitoids was greatest in female treatments, much less in male treatments and least in controls, tending to match the pattern of winged offspring production. In a second set of experiments, directly parasitised aphids produced no greater proportion of winged offspring than unparasitised controls, thus being parasitised itself is not used by aphids for induction of the winged morph. The induction of wing development by parasitoids shows that host defences against parasites may also include an increased rate of dispersal away from infected habitats. While previous work has shown that parasitism suppresses wing development in parasitised individuals, our experiments are the first to demonstrate a more indirect influence of parasites on insect polyphenism. Because predators and parasites differ fundamentally in a variety of attributes, our finding suggests that the wing production in response to natural enemies is of general occurrence in A. pisum and, perhaps, in other aphids.  相似文献   

14.
Wing polyphenism in aphids represents an outstanding example of adaptive phenotypic plasticity. During summer, parthenogenic mother aphids alter the developmental fate of their embryos to produce wingless or winged adult forms in response to high population density (i.e. crowded conditions). Although this maternal effect is well known, the mechanisms underlying transgenerational winged‐morph determination remain largely unresolved. In the present study, the effects of different high‐density treatment durations are tested on the vetch aphid Megoura crassicauda Mordvilko aiming to investigate how and when the density signals detected by mothers are transmitted to embryos. The duration of density treatment shows additive effects on both the number of crowded females producing winged aphids (winged‐producers) and the number of winged progeny. In addition, even when high‐density treatment is stopped, the production of winged offspring continues for several days and depends on the duration of treatment. The results indicate that mother aphids retain high‐density signals for a period after removal of the stimulus. Furthermore, observations of the progeny sequence (i.e. the order in which the offspring are born) and the embryonic stages developing in the mothers reveal that high‐density information may affect embryonic fate at the late embryonic stage immediately before cuticle formation.  相似文献   

15.
Studying the evolutionary history of trait divergence, in particular those related to dispersal capacity, is of major interest for the process of local adaptation and metapopulation dynamics. Here, we reconstruct the evolution of different alleles at the nuclear‐encoded mitochondrial NADP+‐dependent isocitrate dehydrogenase (mtIdh) locus of the ground beetle Pogonus chalceus that are differentially and repeatedly selected in short‐ and long‐winged populations in response to different hydrological regimes at both allopatric and sympatric scales along the Atlantic European coasts. We sequenced 2788 bp of the mtIdh locus spanning a ~7‐kb genome region and compared its variation with that of two supposedly neutral genes. mtIdh sequences show (i) monophyletic clustering of the short‐winged associated mtIDH‐DE haplotypes within the long‐winged associated mtIDH‐AB haplotypes, (ii) a more than tenfold lower haplotype diversity associated with the mtIDH‐DE alleles compared to the mtIDH‐AB alleles and (iii) a high number of fixed nucleotide differences between both mtIDH haplotype clusters. Coalescent simulations suggest that this observed sequence variation in the mtIdh locus is most consistent with a singular origin in a partially isolated subpopulation, followed by a relatively recent spread of the mtIDH‐DE allele in short‐winged populations along the Atlantic coast. These results demonstrate that even traits associated with decreased dispersal capacity can rapidly spread and that reuse of adaptive alleles plays an important role in the adaptive potential within this sympatric mosaic of P. chalceus populations.  相似文献   

16.
In the Appalachian portion of their breeding range, Golden‐winged Warblers (Vermivora chrysoptera) nest in shrubland and regenerating forest communities created and maintained by disturbance. Because populations of Golden‐winged Warblers have exhibited precipitous declines in population throughout their Appalachian breeding range, management activities that create or maintain early successional habitat are a priority for many natural resource agencies and their conservation partners. Within these early successional habitats, however, additional information is still needed concerning the relative importance of different vegetation features in selection of breeding territories by Golden‐winged Warblers. Our objective, therefore, was to use logistic regression to estimate the probability of territory‐level occupancy by Golden‐winged Warblers in north‐central Pennsylvania at two sites, each with its own early successional community, based on vegetation characteristics. Our communities were composed of shrublands and regenerating forest sites resulting from two disturbances: agriculture and forest fire. Despite differences in vegetation structure, portions of both study areas (regenerating forest and old field) supported territorial Golden‐winged Warblers. Probability of territory occupancy by Golden‐winged Warblers increased with percent blackberry (Rubus) cover in the regenerating forest community, and decreased as basal area and distance to microedge increased (i.e., as vegetation patchiness decreased) in both communities. These habitat features have also been found to influence other aspects of Golden‐winged Warbler breeding ecology such as nest‐site selection, pairing success, and territory abundance. Vegetation features influencing Golden‐winged Warbler territory establishment can differ among shrubland and regenerating forest communities, and management decisions and outcomes may be affected by these differences. Our study provides a starting point for a more comprehensive hypothesis‐driven occupancy survey to investigate features of the territories of Golden‐winged Warblers across a broader geographic range and in different vegetation communities.  相似文献   

17.
Hybridization or the interbreeding of genetically discrete populations or species can occur where ranges of genetically distinct units overlap. Golden‐winged warblers Vermivora chrysoptera, a species that has been in steady decline for decades, highlight the potential population‐level consequences of hybridization. A major factor implicated in their decline is hybridization with their sister species, the blue‐winged warbler Vermivora cyanoptera, which has likely been exacerbated by historic and current land‐use practices. We examined habitat associations of golden‐winged and blue‐winged warblers, phenotypic hybrids, and cryptic hybrids (i.e. mismatch between plumage phenotype and genotype as identified by mitochondrial DNA) in an area of relatively recent range overlap and hybridization in northern New York, USA. To explore the robustness of these results, we then compared the patterns from New York with habitat associations from the central Pennsylvanian Appalachian Mountains where blue‐winged warblers either do not occur or are in very low abundance, yet cryptic golden‐winged warbler hybrids are present. From 2008 to 2011, we captured 122 birds in New York and 28 in Pennsylvania and collected blood samples, which we used to determine maternal ancestry. For each bird captured, we measured territory‐level (50‐m radius circles) habitat, and later used remote‐sensing data to quantify habitat on the territories and in surrounding areas (100‐, 250‐, and 500‐m radius circles). In New York, golden‐winged warblers occupied structurally heterogeneous territories surrounded by homogeneously structured, contiguous deciduous forest, far from urban areas. Blue‐winged warblers showed opposite associations, and hybrids’ habitat associations were typically intermediate. In Pennsylvania, the habitat associations of golden‐winged warblers and their cryptic hybrids were remarkably similar to those in New York. These findings suggest that patterns of habitat occupancy by hybrids may promote contact with golden‐winged warblers and thus likely facilitate genetic introgression, even in areas where the parental species are not sympatric.  相似文献   

18.
The mold flora of seeds of twelve varieties of winged beans was determined both before and after surface disinfections. When seeds were surface disinfected, mold fungi were detected in 73% of the seeds whereas 81% of the seed that was not disinfected produced mold fungi. Aspergillus spp. was most frequently present while Penicillium spp. occurred in seed of 4 varieties and in less than 4% of the seed. Twelve isolates oiA. flavus and A. parasiticus were examined for their ability to produce aflatoxins. Whether aflatoxins were produced and the amount of each varied according to the origin of the isolate and the species of Aspergillus. For example all A. parasiticus isolates produced at least 2 aflatoxins whereas 4 of the A. parasiticus isolates were non-toxigenic. When ground seeds of winged beans were inoculated with an aflatoxigenic strain of A. parasiticus the level of aflatoxins that occurred varied with the variety, however, the level of aflatoxin was higher in winged bean than in peanut tissue and 6 of the 12 winged bean varieties contained higher levels of aflatoxins than rice.  相似文献   

19.
Conventional surveys designed to monitor common and widespread species may fail to adequately track population changes of rare or patchily distributed species that are often of high conservation concern. We evaluated the performance of a new monitoring approach that employs both a spatially balanced sampling design and a targeted survey protocol designed to estimate population trends of one such patchily distributed species, the Golden‐winged Warbler (Vermivora chrysoptera), in the Appalachian Mountains Bird Conservation Region (BCR 28), USA. Our spatially balanced survey consisted of 105 sample quads (one‐quarter Delorme Atlas pages) across the current range of Golden‐winged Warblers within BCR 28, each with five sample points located in early successional habitat. From 2009 to 2013, collaborators visited each sample point once per year during the peak breeding season and conducted a 17‐min survey consisting of passive observation and playback of conspecific songs and mobbing vocalizations. We used multi‐season, single‐species occupancy models to estimate probability of quad occupancy, detection probability, and occupancy dynamics for Golden‐winged Warblers and closely related Blue‐winged Warblers (Vermivora cyanoptera). Our survey protocol resulted in high estimates of detection probability for Golden‐winged (92%) and Blue‐winged (79%) warblers, with 47% and 56% of quads estimated to be initially occupied, respectively. Derived population trend estimates (λ) indicated an average decline in population of 6% for Golden‐winged Warblers and 7% for Blue‐winged Warblers, resulting in estimated 21% and 22% declines, respectively, in quad occupancy after 5 yr. Our results demonstrate that coupling a spatially balanced survey design in appropriate habitat with a playback protocol to increase detection rates is a viable strategy for tracking populations of Golden‐winged Warblers in the Appalachian Mountains BCR. Similar survey methods should be considered for other rare, declining, or patchily distributed bird species that require targeted monitoring.  相似文献   

20.
Body size is a life history trait that determines the reproductive success of a variety of organisms. Changes in body size may have a genetic component when persistent conditions such as season length and climate select for individuals of an optimal body size and an environmental component when it is influenced on an ecological scale by factors such as weather, food availability, or maternal effects. Along elevational gradients that experience seasonality, insects commonly become smaller with increases in elevation. In this study we test the hypothesis that dispersal potential, an indicator of gene flow, impacts the type of size clines exhibited by insects along elevational gradients and that these differences in local adaptation should lead to predictable changes in their reproductive potential and output. Using two short winged grasshopper species, Aeropedellus clavatus and Melanoplus boulderensis, and two long winged species, Camnula pellucida and Melanoplus sanguinipes, we showed that species with low dispersal potential are associated with significant declines in body size with increases in elevation while species with high dispersal potential displayed no size clines. Consistent with short winged species being more locally adapted, we show that reproductive potential, as measured by the proportion of ovarioles that become functional, do not differ among populations of short winged species, but decline with elevation in the long winged species. While our study failed to show that dispersal potential impacts reproductive output in a consistent and predictable manner (as measured by clutch and egg sizes), we address the possibility that clutch size may not reflect changes in total reproductive output and that changes in egg size may be a plastic trait. We concluded that studies exploring the evolution of body size, the reproductive capacity and species level responses to environmental change should note the importance of dispersal potential in influencing these patterns.  相似文献   

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