绿豆象气味结合蛋白基因的克隆及表达分析

【目的】对绿豆象Callosobruchus chinensis气味结合蛋白(odorant binding proteins, OBPs)基因进行克隆、鉴定和组织表达分析,为研究OBPs在绿豆象嗅觉感受过程中的功能奠定基础。【方法】基于绿豆象触角转录组数据,通过RT-PCR克隆绿豆象6个OBP基因并进行生物信息学分析;通过qRT-PCR分析OBP基因在绿豆象雌雄成虫头(不含触角)、触角、腹、足和翅各组织中的表达情况。【结果】获得了6个绿豆象OBP基因的开放阅读框,命名为CchiOBP1-CchiOBP6(GenBank登录号: MN832700-MN832703, MN901841-MN901842);CchiOBP5为一段C端不完整的Minus-C OBP,其余均属于完整的Classical OBPs,预测6个CchiOBPs均含有信号肽。系统发育分析表明CchiOBP1, CchiOBP2和CchiOBP5与叶甲科(Chrysomelidae)昆虫OBPs的亲缘关系较近,CchiOBP3, CchiOBP4和CchiOBP6与天牛科(Cerambycidae)昆虫OBPs的亲缘关系较近。qRT-PCR结果表明,6个CchiOBPs基因在绿豆象成虫的触角、头(不含触角)、腹、翅和足部均有不同的表达量,CchiOBP1-4和CchiOBP6在雌雄成虫触角中均呈现高表达,且极显著高于在其他组织中的。CchiOBP5在雌成虫触角和头部(不含触角)中呈现高表达,但在雄成虫中表现为在足部的表达量显著高于在其他组织中的,在触角中的表达量最低。【结论】确定了绿豆象6个CchiOBPs基因的核苷酸和氨基酸序列组成,其中有5个CchiOBPs基因在绿豆象雌雄成虫触角中高表达,推测其在绿豆象嗅觉识别寄主植物过程中发挥重要作用。     

Tetrameres tarapungae n.sp. (Nematoda: Spirurida), a parasite of the red-billed gull,Larus novaehollandiae scopulinus

Abstract

Tetrameres (Tetrameres) tarapungae n.sp. is described from specimens from the proventriculus of juvenile red-billed gulls from Kaikoura, New Zealand. The male is characterised by having two short rows of lateral cervical cuticular spines that do not extend beyond the middle of the oesophagus, a body length of 2.2–2.6 mm, and the larger spicule longer than half the body length. The male tail bears four pairs of subventral papillae and two pairs of lateral papillae. The pathology of the infections is described briefly.     

Insecticidal activity of Poppy (Papaver somniferum L.) seed oil against cowpea weevil (Callosobruchus maculatus F.) in stored cowpea

In this study, the insecticidal effect of Poppy (Papaver somniferum) seed oil was investigated against Callosobruchus maculatus (Bruchidae) in cowpea, at different concentrations and exposure time. The Poppy seed oil at 2, 4, 6, 8 and 10?ml/kg was tested against adults of C. maculatus, and the mortality was counted after 24, 48 and 72?h of exposure. All tests were conducted at 27–30?°C and 65?±?5% r.h. The experiments were carried out based on the factorial experiment by randomized complete design with four replications. Twenty-five insects with 0–24?h old were used for each replication. The effect of Poppy seed oil on the reduction of emergence of insects in next generation (F₁) was also assayed. The results of experiments indicate the significant differences between concentrations and exposure time (p?<?0.0001), and the increase of concentrations and exposure time increased mortality. The amount of mortality at high concentrations was remarkable, and highest mortality rate (96.91%) was recorded at 10?ml/kg, after 72?h of exposure. The application of oil significantly reduced F₁ progeny production and even at lowest concentration (2?ml/kg), the amount of F₁ production was reduced more than 70%, compared with control treatment. Complete (100%) reduction in progeny production was recorded at the rates of 8 and 10?ml/kg. The results of seed germination assay showed no significant differences between control and treated seed, and no harmful effect was observed on the seed germination. These results proved that Poppy seed oil can be used as a controlling agent of storage pests, especially C. maculatus, although more detailed studies are necessary.     

INBREEDING DEPRESSION INCREASES WITH ENVIRONMENTAL STRESS: AN EXPERIMENTAL STUDY AND META‐ANALYSIS

Inbreeding–environment interactions occur when inbreeding leads to differential fitness loss in different environments. Inbred individuals are often more sensitive to environmental stress than are outbred individuals, presumably because stress increases the expression of deleterious recessive alleles or cellular safeguards against stress are pushed beyond the organism's physiological limits. We examined inbreeding–environment interactions, along two environmental axes (temperature and rearing host) that differ in the amount of developmental stress they impose, in the seed‐feeding beetle Callosobruchus maculatus. We found that inbreeding depression (inbreeding load, L) increased with the stressfulness of the environment, with the magnitude of stress explaining as much as 66% of the variation in inbreeding depression. This relationship between L and developmental stress was not explainable by an increase in phenotypic variation in more stressful environments. To examine the generality of this experimental result, we conducted a meta‐analysis of the available data from published studies looking at stress and inbreeding depression. The meta‐analysis confirmed that the effect of the environment on inbreeding depression scales linearly with the magnitude of stress; a population suffers one additional lethal equivalent, on average, for each 30% reduction in fitness induced by the stressful environment. Studies using less‐stressful environments may lack statistical power to detect the small changes in inbreeding depression. That the magnitude of inbreeding depression scales with the magnitude of the stress applied has numerous repercussions for evolutionary and conservation genetics and may invigorate research aimed at finding the causal mechanism involved in such a relationship.     

Independence of genetic variation between circadian rhythm and development time in the seed beetle, Callosobruchus chinensis

A positive genetic correlation between periods of circadian rhythm and developmental time supports the hypothesis that circadian clocks are implicated in the timing of development. Empirical evidence for this genetic correlation in insects has been documented in two fly species. In contrast, here we show that there is no evidence of genetic correlation between circadian rhythm and development time in the adzuki bean beetle, Callosobruchus chinensis. This species has variation that is explained by a major gene in the expression and period length of circadian rhythm between strains. In this study, we found genetic variation in development time between the strains. The development time was not covaried with either the incidence or the period length of circadian rhythm among the strains. Crosses between strains suggest that development time is controlled by a polygene. In the F₂ individuals from the crosses, the circadian rhythm is attributable to allelic variation in the major gene. Across the F₂ individuals, development time was not correlated with either the expression or the period length of circadian rhythm. Thus, we found no effects of major genes responsible for variation in the circadian rhythm on development time in C. chinensis. Our findings collectively give no support to the hypothesis that the circadian clock is involved in the regulation of development time in this species.     

Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus

The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.     

Ultrastructural study of embryonic and early adult germ cells,and their support cells,in both sexes of Xiphophorus (Teleostei:Poeciliidae)

The ultrastructure of the early spermatogonia in mature testes of the platyfish, Xiphophorus maculatus, was compared to that of oogonia in mature ovaries of X. maculatus and the related X. nigrensis. Both cell types were very similar and, characterized as being large, oval to round cells containing large, central nuclei with prominent nucleoli. Abundant mitochondria with sparse transverse cristae were located at one pole or around the nucleus. Annulate lamellae and electron-dense granular material (nuage) were present. Other organelles were not prominent. A female that had received a testis graft had testicular tissue containing mature spermatozoa within the ovary, indicating that cells were present that could develop along the male line. Special crosses were carried out to obtain all-male embryos of X. maculatus and all-female embryos of X. nigrensis. The ultrastructure of the germ cells in all embryonic gonads was similar to that of the adult cells. These results suggest the presence of sexually undifferentiated germ cells in the adult gonads of both sexes. The support cells investing all of these germ cells were also similar structurally and appeared to be undifferentiated.     

四种基质表面上常规杀虫剂对四纹豆象的药效评价（英文）

在害虫治理中, 在消费或贮藏粮食加工产品的建筑设施或场所进行害虫防治需要将杀虫剂施用在各种基质表面上。为了测定不同基质表面上杀虫剂的药效, 将四纹豆象Callosobruchus maculatus (F.)成虫接触田间推荐剂量的阿维菌素、 溴氰菊酯和毒死蜱。结果表明： 施用在玻璃、 瓷砖、 塑料和纸盘表面上, 阿维菌素对四纹豆象成虫的致死率分别为63.33%, 22.41%, 12.9%和11.9%, 而溴氰菊酯在这4种基质表面上对四纹豆象成虫的致死率分别为 55%, 44.2%, 41.3%和 37.4%。在所有基质表面上接触毒死蜱, 四纹豆象成虫的死亡率均为100%。对数据进行的Probit 分析表明, 毒死蜱制剂在玻璃、 瓷砖、 塑料和纸盘上对四纹豆象成虫 的LC₅₀ 值分别为 8.66, 13.6, 29.16和 56.5 μg/mL, 阿维菌素制剂的相应数值分别为119.4, 446.2, 774.2 和 836.4 μg/mL, 溴氰菊酯制剂的相应数值分别为 1 008, 1 131, 1 210和 1 336 μg/mL。据此推断, 毒死蜱对四纹豆象的毒性最强, 且在玻璃、 瓷砖、 塑料和纸盘表面上的毒性依次降低。     

Determinants of oviposition in Acanthoscelides obtectus: a nonconformist bruchid

Abstract. Acanthoscelides obtectus is atypical of bruchids found in stored seeds because females do not attach eggs individually to host seeds but scatter them irregularly among potential hosts. In other respects, its life history resembles that of other species and comparison provides evidence for the adaptive nature of their behaviour. Individual females differ dramatically in the temporal pattern of their oviposition. The hypothesis is proposed that this is an adaptation to life in heterogeneous habitats. Oviposition is not regulated by host availability to the same extent as in other bruchids, providing evidence that regulation of the number of eggs laid by species which stick eggs to host seeds is an adaptation to the abundance of hosts. The continued presence of males and opportunity for multiple matings does not affect fecundity or egg viability. Females preferentially lay on clean seeds when provided with a choice between them and seeds previously exposed to other adult beetles. However, they do not appear to be deterred by, or cannot detect, the presence of larvae infesting seeds. Other bruchid species avoid such seeds that they can identify by the occurrence of egg cases and pheromones. The number of eggs laid is influenced by the host cultivar available for oviposition. Oviposition by A. obtectus appears to be an adaptation to both storage environments and the heterogeneous environment of a growing crop or uncultivated land. Its behaviour suggests an ancestral condition in bruchids and the changes which might have occurred in the ecology of other bruchid species as they have adapted to become pests of human seed stores.