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1.
1. Diapause is generally believed to entail costs that manifest themselves as decreased survival, rate of development, and/or reproduction after diapause completion. The present study is a first step in investigating such diapause costs in the spider mite Tetranychus urticae.
2. The relationship was assessed between diapause duration and the post-diapause life-history traits of longevity and egg production, under six photoperiods at 19 °C.
3. The relationship between diapause duration and longevity was negative under five out of six treatments; in three cases this negative relationship was significant.
4. Most evident were the negative correlations between diapause duration and rate of oviposition, peak rate of oviposition, and total egg production. These phenotypic correlations suggest that there may be a trade-off between diapause duration and post-diapause reproduction.  相似文献   

2.
A trade-off between diapause duration and fitness in female parasitoids   总被引:5,自引:0,他引:5  
Abstract 1. Diapause allows insects to cope with adverse weather conditions but also poses substantial fitness costs, e.g. through reduced survival of the diapausing stage or sublethal effects in the following season.
2. The energetic costs of diapause in females of the parasitoid Asobara tabida Nees (Hymenoptera: Braconidae) were assessed using experimental manipulation of diapause duration.
3. An increase in diapause length not only led to higher mortality among diapausing pupae but also caused a significant decrease in egg load, fat reserves, and dry weight of the emerging adult females.
4. Only larvae with sufficient resources were able to survive the entire diapause period and there was a trade-off between the metabolic costs of diapause and adult fitness components.
5. In contrast, the size (tibia length) of emerging females increased with increasing diapause duration. It is proposed that this may be due to a genetic correlation between larval dry weight and adult size, so that selection for heavier larvae would result in larger adults even when resources are limited.
6. Ultimately, the evolution of diapause duration and its consequences for adult performance will depend on the costs of overwintering and the ecological conditions in the habitat.  相似文献   

3.
Abstract.  1. A facultative mutualistic relationship between a herbivorous moth, Lobesia botrana , and a phytopathogenic fungus, Botrytis cinerea , both damaging the same plant, the vine, has been demonstrated recently. Laboratory and field studies were carried out to determine the influence of the presence of the fungus in food on larvae during the pre- and post-diapause periods and on the global fitness of the insect.
2. During the pre-diapause period, larvae fed on fungus exhibited a higher survival rate and a faster larval development than insects reared without fungus.
3. After the wintering diapause, insects reared with fungus displayed a better synchronisation of adult emergence and an increased fecundity compared with control insects.
4. These results indicate that food containing fungus provides an improved diet, permitting the herbivorous insect to obtain nutrients required to optimise their life-history traits.
5. In addition, the results emphasise the importance of the nutritional quality of larval diet, improved by addition of the fungus, on diapause termination and on the demography of the insect before and after the wintering diapause.  相似文献   

4.
昆虫滞育后的生物学特性   总被引:1,自引:1,他引:0  
从昆虫滞育后性比、寿命、生殖力和重复滞育等方面对昆虫滞育后的生物学特性进行了概括,并分析了影响昆虫滞育后生物学特性数量表达的因子。这些因子包括:(1)滞育前昆虫的发育速率、取食行为和个体大小;(2)滞育期间的环境条件及昆虫取食行为;(3)滞育持续期;(4)滞育后的取食需求;以及(5)滞育后的温度和光周期。  相似文献   

5.
Abstract The apple leaf miner Phyllonorycter ringoniella (Matsumura) (Lepidoptera: Gracillariidae) overwinters as a diapausing pupa. The diapause rate reaches 100% in early October. Diapause intensity decreases gradually from early October and diapause terminates in early February. The fresh body weight of diapausing pupae is 1.6 times that of non-diapausing pupae. The main cryoprotectant in P. ringoniella pupae is trehalose. Three stages are distinguishable as indicated by the correlations between diapause intensity, levels of cold hardiness and the trehalose content: diapause induction occurred in October, diapause development from November to December, and post-diapause quiescence from January to April. During diapause induction, the pupae accumulate low levels of trehalose and do not survive exposure to −15 °C. During diapause development, the pupae gradually accumulate more trehalose and show some ability to survive exposure to −15 °C, but not to −20 °C. During post-diapause quiescence, the pupae accumulate relatively more trehalose and cold hardiness fully develops, but decreases quickly in April. The trehalose content in pupae sampled in December is unaffected by acclimation temperatures in the range 0–30 °C, but decreases in pupae sampled in March after acclimation at temperatures from 5 to 15 °C. These results suggest that overwintering pupae of P. ringoniella have the ability to accumulate trehalose and develop a high level of cold hardiness during diapause development.  相似文献   

6.
Bégin M  Roff DA 《Heredity》2002,89(6):473-479
A covariation between wing morphology and diapause occurrence has been observed in many insect species, but the genetic basis of this covariation has never been established. This study measures the heritability of, and genetic correlation between, these two ecologically important threshold traits in the cricket Gryllus veletis. A total of 81 full-sib families were reared in the laboratory to estimate these parameters. A comparison of laboratory and field samples showed that these two traits are highly plastic. The heritability of wing morphology was 0.25 (0.09), the heritability of diapause occurrence was 0.77 (0.11) and the genetic correlation between them was 0.61 (0.19). These estimates did not differ between males and females. The significance of these quantitative genetic parameters is discussed with reference to the monomorphism of natural populations of G. veletis for diapause occurrence and with reference to the trade-off between the ability to disperse by flight and the ability to diapause found in at least one closely related species. A survey of the literature reveals that genetic correlations between diapause occurrence or wing morphology and various other traits are common in insects, suggesting that these two traits are often genetically integrated in insect life-histories.  相似文献   

7.
In arthropods, both diapause duration and ability to produce eggs in early adult life (early fecundity) are important life‐history traits for successful settling in a new habitat. In herbivorous spider mites (Acari: Tetranychidae), inbreeding frequently occurs because new colonies are established by only one or a few females. In the present study, we investigated the impact of inbreeding on the phenotypic variance in diapause duration and early fecundity in the Kanzawa spider mite, Tetranychus kanzawai Kishida. Diapause duration was compared between the inbreeding treatment (strongly inbred strains) and the control (strains immediately taken from the stock culture) under winter‐mimicking laboratory conditions. The variance in diapause duration was smaller in the inbreeding treatment than in the control, though the magnitude of decrease of variance was less than expected. On the other hand, early fecundity did not show any reduction of variance. The present results revealed that inbreeding reduces phenotypic variation, as expected in theory.  相似文献   

8.
草地螟滞育幼虫的蛋白和核酸含量变化   总被引:2,自引:0,他引:2  
为了阐明草地螟Loxostege sticticalis 滞育的分子调控基础, 本研究应用Trizol法、 DNA和蛋白质定量试剂盒、 SDS-PAGE电泳技术分别对进入滞育1, 2, 3和4个月、 解除滞育以及非滞育草地螟老熟幼虫中的核酸含量、 总蛋白含量和组分的变化进行了测定。结果表明: 滞育不同月份幼虫的总RNA含量显著低于非滞育幼虫的总RNA含量(P<0.05); 解除滞育幼虫的总RNA含量显著高于滞育2, 3和4个月的幼虫, 但仍显著低于非滞育的对照组。滞育不同月份、 非滞育以及解除滞育幼虫的总DNA含量没有显著差异(P>0.05)。RNA/DNA比值随滞育的开始而显著下降, 随着滞育的结束而显著上升。滞育不同月份的幼虫总蛋白含量显著高于非滞育幼虫的总蛋白含量(P<0.05), 但解除滞育与非滞育幼虫的总蛋白含量无显著差异。利用SDS-PAGE电泳分析发现滞育幼虫体内存在滞育关联蛋白, 蛋白条带在24 kDa左右, 但非滞育和已经解除滞育的幼虫则没有该蛋白条带。这些结果表明, 总RNA含量的降低、 RNA/DNA比值下降、 总蛋白含量的升高, 以及24 kDa蛋白的存在是草地螟幼虫滞育的主要生理特征。  相似文献   

9.
Latitudinal clines are widespread in Drosophila melanogaster, and many have been interpreted as adaptive responses to climatic variation. However, the selective mechanisms generating many such patterns remain unresolved, and there is relatively little information regarding how basic life-history components such as fecundity, life span and mortality rates vary across environmental gradients. Here, it is shown that four life-history traits vary predictably with geographic origin of populations sampled along the latitudinal gradient in the eastern United States. Although such patterns are indicative of selection, they cannot distinguish between the direct action of selection on the traits in question or indirect selection by means of underlying genetic correlations. When independent suites of traits covary with geography, it is therefore critical to separate the widespread effects of population source from variation specifically for the traits under investigation. One trait that is associated with variation in life histories and also varies with latitude is the propensity to express reproductive diapause; diapause expression has been hypothesized as a mechanism by which D. melanogaster adults overwinter, and as such may be subject to strong selection in temperate habitats. In this study, recently derived isofemale lines were used to assess the relative contributions of population source and diapause genotype in generating the observed variance for life histories. It is shown that although life span, fecundity and mortality rates varied predictably with geography, diapause genotype explained the majority of the variance for these traits in the sampled populations. Both heat and cold shock resistance were also observed to vary predictably with latitude for the sampled populations. Cold shock tolerance varied between diapause genotypes and the magnitude of this difference varied with geography, whereas heat shock tolerance was affected solely by geographic origin of the populations. These data suggest that a subset of life-history parameters is significantly influenced by the genetic variance for diapause expression in natural populations, and that the observed variance for longevity and fecundity profiles may reflect indirect action of selection on diapause and other correlated traits.  相似文献   

10.
In many herbivorous arthropods, incidence of diapause, which is considered to reflect the timing of diapause, changes depending on the host plants they utilize. Several theoretical studies suggest that the optimal timing of diapause induction depends on life‐history traits; if the development time of the arthropod is short, fecundity is high, or survival rate remains high throughout the season, the optimal timing of diapause induction would be shifted toward the end of the season. For herbivorous arthropods, these life history traits may change among their host plants. Here we examined whether a population of the Kanzawa spider mite, Tetranychus kanzawai Kishida (Acari: Tetranychidae), shows the predicted pattern of diapause induction on two host plants, the kidney bean [Phaseolus vulgaris (Leguminosae)] and Japanese Orixa [Orixa japonica (Rutaceae)], on which the mites show different performances. Rearing conditions were controlled in two ways. In the first experiment, day length and temperature were kept constant throughout the mite lifetime at either of three conditions from mid October to early November. In the second experiment, the conditions were changed from 20 °C and L11.5:D12.5 at immature stages to 18 °C and L11:D13 at adult stage in order to better approximate field conditions. In the first experiment, diapause incidence on P. vulgaris was lower than on O. japonica. This tendency became stronger in the second experiment, suggesting a difference in the timing of diapause induction among host plants. On the other hand, P. vulgaris was proven to allow high performance, i.e., greater lifetime fecundity and shorter development times, although it had no effect on the survival rate. The relationship between diapause incidence and performance is consistent with the prediction of theoretical studies that a short development time or high fecundity delays the timing of diapause induction.  相似文献   

11.
We investigated eight populations of Drosophila immigrans from low to high montane localities (600–2202 m) for altitudinal variations in abdominal melanization and fitness-related traits (desiccation resistance, copulation duration, and fecundity). On the basis of common garden experiments, persistence between-population differences at 21°C suggests that observed variations in fitness-related traits have a genetic basis. Parent–offspring regression analyses showed higher heritability (h2= 0.77) for melanization patterns on all the abdominal tergites. All the traits showed significantly higher repeatability across generations. Under colder and drier environments in dispersed montane localities, abdominal melanization and desiccation resistance significantly increased (1.5–1.9 fold) along altitude. Thus, there are correlated effects of abdominal melanization on desiccation resistance. Genetic correlations, based on family means, were significantly high between abdominal melanization and other fitness traits. Furthermore, darker flies along increasing altitude resulted in a 35–40% increase in copulation duration as well as fecundity. There are significantly positive correlations of abdominal melanization with copulation duration as well as fecundity on the basis of within- as well as between-population variations. Such observations are in agreement with the thermal budget hypothesis. Present data suggest that changes in body melanization impact fitness-related traits in montane populations of Drosophila immigrans .  相似文献   

12.
Abstract.  1. Most temperate insects undergo diapause at a specific developmental stage to overcome severe winters. The bruchine beetle Bruchidius dorsalis in a warmer region in Japan, however, has diverse over-wintering stages – non-diapausing larvae, diapausing larvae, and diapausing adults, whereas in a cooler region, it over-winters only as the final instar larva or adult in diapause.
2. The geographical pattern of over-wintering stages in 12 populations was investigated over a wide range along the mainland of Japan. It revealed that a distinct geographical pattern of over-wintering stages exists in relation to temperature conditions. In regions with warmer climates, the proportion of non-diapausing larvae increased and B. dorsalis had a more complex over-wintering stage structure.
3. Life cycles were also compared between two areas of Japan by field experiments. In the cooler area, the first generation over-wintered in the diapausing larval or adult stage. Conversely, in the warmer area, diapause was induced later and some of the first-generation adults produced second-generation offspring before over-wintering.
4. Based on the geographical cline of climates and the differences in cold hardiness among stages, we can demonstrate that the over-wintering stage variation among and within populations results from an adaptive timing of diapause induction in each region, because the late larval or adult diapauses protect pupae or eggs – which unlike other stages are not cold hardy – from being produced late in the season.  相似文献   

13.
Abstract.  1. Seasonality is a prime selective factor expected to result in local adaptation of life cycles and dormancy. Genetic differentiation in diapause response was investigated along a European latitudinal cline in the dung fly Scathophaga stercoraria (Diptera: Scathophagidae). Such differentiation may be mediated by additive or dominance genetic and/or maternal effects, which need to be distinguished.
2. Replicate sibships from five European populations (Lugano, Switzerland: 46.00°N; Zurich, Switzerland: 47.37°N; Oxford, U.K.: 51.75°N; Lund, Sweden: 55.70°N; Reykjavik, Iceland: 64.15°N) were raised in a common laboratory environment known to induce pupal winter diapause (12 °C and 12 h light), revealing a genetic latitudinal cline in both the proportion of individuals entering diapause and diapause duration in response to winter length estimated from weather data.
3. Populations from the extremes of the cline (Lugano and Reykjavik) were further reciprocally crossed to investigate the underlying genetics. This experiment revealed evidence for diapause induction at 12 °C being dominant (i.e. not merely additive) and clearly rejected maternal effects as the primary source of this between-population variation.  相似文献   

14.
Abstract.  1. Voltinism may be conceptualised as the product of development rate and the timing of diapause – two components that together translate gradual environmental variation, through periods of growth and development, into 'generational units'. This may result in very different selection pressures on diapause induction and development time in populations with different numbers of generations per year.
2. Developmental data from univoltine and bivoltine populations of the butterfly Aricia agestis (Lepidoptera: Lycaenidae) in North Wales were used to examine larval development time and the timing of diapause, and their contribution towards voltinism in populations that occur at the same latitude and in geographic proximity to one another along a thermal gradient.
3. The critical photoperiod for diapause induction in univoltines and bivoltines from the same latitude differed by more than 1.5 h.
4. Development time also differed significantly between these populations, in line with predictions that bivoltines would need to exhibit shorter development times in order to achieve two complete generations per year. Shorter development times for bivoltines result in lower pupal weights, suggesting a trade-off exists between generation number and body size that may dictate the position of the transition zone between the two life-history strategies. Analysis of development times in a third population, from southern England, with greater thermal availability than those from North Wales, further supports this hypothesised trade-off.
5. To achieve the conversion of a continuous thermal gradient into the binary biological response from univoltism to bivoltism, bivoltines speed up development, reduce adult body size and shift their diapause induction response.  相似文献   

15.
Diapause is a strategy used by many insect species to survive adverse environmental conditions. However, diapause incurs costs that may have adverse effects on post‐diapause development and reproduction. We herein investigated the effects of diapause on the post‐diapause reproductive investment of males and females in a multivoltine moth, the adzuki bean borer, Ostrinia scapulalis (Walker) (Lepidoptera: Crambidae). We found that (1) post‐diapause males and females were smaller and had lower mating success than non‐diapause individuals, (2) post‐diapause females had lower fecundity and shorter longevity than non‐diapause females, (3) post‐diapause males transferred similar numbers of eupyrene and apyrene sperm as non‐diapause males, (4) the fecundity and longevity of non‐diapause females mated with post‐diapause males and those mated with non‐diapause males were not significantly different, and (5) no significant relationship was found between diapause duration (short and long) and post‐diapause reproductive investments in both males and females. These results suggest that post‐diapause males did not reduce reproductive investment in spite of the cost of diapause, and the significant decline in reproductive output in post‐diapause females was due to their reduced body weight and longevity, which appeared to be direct consequences of the cost of diapause.  相似文献   

16.
Regulation of host diapause by an insect parasitoid   总被引:1,自引:0,他引:1  
Abstract. 1. The interaction between larval development and parasitism by the braconid wasp Cotesia koebelei (Riley), was investigated in a population of the butterfly Euphydryas editha (Boisduval) (Nymphalidae). In this population, the butterfly host has an obligatory overwintering larval diapause.
2. It was found that E. editha larvae harbouring parasitoids were more likely to pass through an extra feeding instar before entering diapause than were non-parasitized conspecifics.
3. In addition, some individuals that were experimentally exposed to multiple parasitoid attacks bypassed diapause completely; these larvae passed through five or six feeding instars, reaching sizes typical of final instar post-diapause larvae.
4. The observed effect of superparasitism occurred regardless of whether the host larvae subsequently produced mature parasitoids, suggesting that parasitoid attack is sufficient to invoke the response.
5. It is proposed that the parasitoid C.koebelei regulates the number of pre-diapause feeding instars of its insect host E. editha, and that some component of the female venom, injected at oviposition, is responsible for this regulation.  相似文献   

17.
The possible associations between longevity, early fecundity, and stress-resistance traits were explored using artificial selection on longevity in a laboratory population of Drosophila buzzatii . Three replicated lines were selected for increased lifespan (L lines) and compared with the respective unselected controls (C lines) after the 14th generation of selection. Mean longevity exhibited a significant response to selection. The baseline mortality tended to decrease in the L lines and a negative correlated response to longevity selection was found for early fecundity. Egg-to-adult developmental time increased in L lines. Longevity selection increased stress resistance for both high and low temperatures, as measured by heat knockdown resistance and chill-coma recovery. Starvation resistance also tended to be higher in L than in C lines. The results obtained are consistent with the hypothesis of trade-offs between longevity and early fecundity, and also suggest a trade-off association between adult longevity and developmental time. Correlated selection responses were generally consistent with correlations among the traits previously inferred from altitudinal clines for longevity and stress-resistance phenotypes.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 738–748.  相似文献   

18.
Abstract.  1. In phytophagous insects, life-history traits mainly depend on host plant range. Substantial longevity, high fecundity and larval competition are the major traits of polyphagous Tephritidae while species with a restricted host range generally exhibit a lower longevity and fecundity as well as mechanisms to avoid larval competition. Our aim in this study was to investigate the life history of an oligophagous species, the tomato fruit fly, Neoceratitis cyanescens (Bezzi).
2. We determined life tables under laboratory conditions in order to calculate the main demographic parameters of N. cyanescens and studied the influence of larval and adult diet on life-history traits.
3. The mean longevity of N. cyanescens females was 40 days. There was a strong synchronisation of female maturity. Oviposition showed an early peak at 9–13 days after a short pre-oviposition period (6 days). The absence of proteins in the adult diet both delayed ovarian maturation and decreased female fecundity. In addition, females originating from tomato fruits produced significantly more eggs than females originating from bugweed or black nightshade, showing that even the larval host plant may strongly affect the subsequent fecundity of adult females.
4. The traits of N. cyanescens are then discussed in the light of those documented for polyphagous and monophagous tephritids. Neoceratitis cyanescens displayed attributes intermediate between those of polyphagous and monophagous tephritids. Its smaller clutch size compared with polyphagous species and its specialisation on the Solanaceae family whose fruits contain toxic compounds may help in reducing intra- and inter-specific competition, respectively.  相似文献   

19.
Phenotypic characters may covary negatively because they are in a trade-off or positively because they contribute to a single function. Genetic correlations can be used to test the validity and generality of these functional relationships by indicating the level of genetic integration and checking the conditions under which they are expressed. Phenotypic correlations indicate that there is a widespread trade-off between flight capability and early fecundity in insects. Different wing morphs (long and short wing) are thought to have a suite of reproductive and flight capability traits. In a half-sib mating experiment, we estimated phenotypic relationships between two flight-capability-related characters (flight muscle condition, wing morph) and two components of early fecundity (number of eggs in the ovaries, number of eggs laid), as well as genetic correlations relating wing morph and both components of fecundity in the wing-dimorphic cricket, Gryllus firmus. The number of eggs in the ovaries and the number of eggs laid were negatively correlated phenotypically and genetically with wing length morph (i.e., long wings associated with low fecundity). Both fecundity characters differed between wing morphs, but only if flight muscle was present and not histolyzed. The phenotypic and genetic correlations between fecundity characters were not significant. This suggests that the phenotypic relationship between ovary development and eggs laid is complex, they are not genetically integrated, and they may evolve independently. However, both early fecundity characters are functionally and genetically integrated within the trade-off to a similar degree. Finally, the trade-off affects early fecundity of both wing morphs suggesting that the functional relationship depends on flight muscle size. Received: 1 December 1998 / Accepted: 20 May 1999  相似文献   

20.
Abstract.  1. The presence of an across-species trade-off between dispersal ability and competitive ability has been proposed as a mechanism that facilitates coexistence. It is not clear if a similar trade-off exists within species. Such a trade-off would constrain the evolution of either trait and, given appropriate selection pressures, promote local adaptation in these traits.
2. This study found substantial levels of heritable variation in competitive ability of the pea aphid, Acyrthosiphon pisum Harris (Homoptera: Aphididae), measured in terms of relative survival when reared with a single clone of the vetch aphid, Megoura viciae Buckton (Homoptera: Aphididae).
3. Pea aphids can move to new patches by either flying (longer distance dispersal) or walking (local dispersal) from plant to plant. There was considerable clonal variation in dispersal ability, measured in terms of the proportion of winged offspring produced, and ability to survive away from their host plant.
4. Winged individuals showed longer off-plant survival times than wingless forms of the same pea aphid clone.
5. There was no evidence of a relationship between clonal competitive ability and either measure of dispersal ability, although the power of the test is limited by the number of pea aphid clones used in the trial.
6. However, there was a positive correlation between clonal fecundity and the proportion of winged offspring produced. Although speculative, it is suggested that clones that are more likely to either overwhelm their host plant or attract higher numbers of natural enemies as a result of having higher fecundity are more likely to produce winged morphs.  相似文献   

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