The oviposition biology of siricid woodwasps in Europe

Abstract. 1. The oviposition biology of the siricid woodwasps, Sirex noctilio, S.juvencus, S.cyaneus, Urocerus gigas, U.augur, U.fantoma, U.sah and Xeris spectrum was investigated. The fecundity of each siricid species was related to adult size although S.noctilio laid relatively fewer eggs than other species.
2. Oviposition drill architecture in host trees is characteristic for the different siricid genera and was found to be related to the length of the ovipositor. The shape of the egg is also characteristic for each genus.
3. Species of the symbiotic fungus, Amylostereum , were found to be associated with all species except X. spectrum. The emplacement of fungus in relation to oviposition drills was investigated.
4. S.noctilio females have relatively larger mucus glands and reservoirs than other siricid species.
5. The response of X.spectrum females to previously infested timber was studied experimentally. A positive response to previously infested timber and Amylostereum inoculated sawdust was demonstrated.
6. The longevity of adults, oviposition rates and incubation period of eggs was investigated.
7. The results are discussed in relation to the ecology of siricids in Europe and Australia.     

Experimental studies on the responses of European siricid woodwasps to host trees

A study was made of the oviposition responses of the siricid woodwasps, Sirex noctilio, S. juvencus, S. cyaneus and Urocerus gigas to experimentally debilitated spruce and pine trees. Treatments included felled, fire-burned, logged and girdled trees which were treated at intervals before bioassay with cages siricid females. In comparable treatments, S. noctilio showed a distinct preference for pines although it was quite successful on spruce while the other siricid species displayed a preference for spruce. The Sirex species successfully attacked more recently treated material although U. gigas showed a preference for timber in a more advanced state of debility. All species showed preferences for girdled trees although other treatments were also favoured by the different siricid species. Overall, the siricids preferred the area above the girdle irrespective of tree species and there was a higher rate of eggs above the girdle in treated spruce trees. A wide range of moisture content in the timber appeared to have no effect on drilling activity or the successful development of eggs. The response of a wild population of S. juvencus to the treated spruce is also described. The results are discussed in relation to the ecology of Siricidae in Europe and the establishment of S. noctilio in Australia. It is suggested that of the species studied, only S. noctilio poses a serious threat to the living pine stands of Australia.     

Within-tree distributions of the Sirex noctilio Fabricius (Hymenoptera: Siricidae)--parasitoid complex and development of an optimal sampling scheme

Little is known about the introduced European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae), and its hymenopteran parasitoid complex in North America. To assess within-tree and landscape-level densities and distributions of these insects, and develop a more cost effective approach for sampling and monitoring S. noctilio, 18 infested pines (12 P. resinosa Aiton and six P. sylvestris L.) were felled from six stands within three regions in central New York and cut into 0.5-m bolts. Bolts were carefully split to recover all siricids (S. noctilio and native siricids) and parasitoids. In total, 2,558 siricids were recovered; 1,972 siricid larvae and 586 teneral adult S. noctilio. Parasitism of siricids, a majority of which were S. noctilio based on larval rearing results, was 16.4% with Ibalia leucospoides ensiger Norton causing 10.7% of the documented mortality. Numbers of siricids and parasitoids declined 33-86% from the northern to the southern sampling regions, peak insect densities occurred in sections of the bole 15-19 cm in diameter and numbers of insects were generally higher in P. sylvestris than P. resinosa according to the highest ranked zero-inflated poisson and probit regression models. Bark thickness was not correlated with siricid or parasitoid species densities. We also describe sampling plans where as few as two 0.5-m samples from infested trees provided reliable within-tree insect densities.     

Natural enemies associated with Sirex noctilio (Hymenoptera: Siricidae) and S. nigricornis in Ontario, Canada

Sirex noctilio F. is an exotic woodwasp now found in eastern North America where it shares natural enemies with native woodwasps of Pinus spp. To study the extent to which native hymenopteran parasitoids and parasitic nematodes could affect woodwasp populations, 60 Pinus trees with symptoms of S. noctilio attack were felled in 2007 and 2008 in Ontario, Canada. Each tree bole was cut into 1-m sections that were placed in individual rearing tubes; emergence was monitored from May to November of the year of felling. Female S. noctilio were dissected to assess parasitism by the nematode Deladenus siricidicola Bedding. Two species of Siricidae emerged from these trees; S. noctilio, which accounted for most of the specimens collected, and S. nigricornis F. Of the three species of parasitoid that emerged, Ibalia leucospoides (Hochenwarth) was the most abundant, accounting for an overall hypothetical Siricidae parasitism rate of almost 20%. This parasitoid emerged over a similar time period as S. noctilio-between early July and early September. Except in trees >15 m in height, parasitism by I. leucospoides generally appeared uniform throughout the bole. Parasitism rates did not vary between the 2 yr, but did between sites in 1 yr. Parasitic nematodes were found in the haemocoel of about one third of S. noctilio females dissected but were never found sterilizing the eggs; none were found in S. noctilio emerging from P. resinosa. These findings suggest that I. leucospoides is currently the primary invertebrate natural enemy of S. noctilio in Ontario.     

Community composition and phenology of native Siricidae (Hymenoptera) attracted to semiochemicals in Minnesota

As a result of the introduction of Sirex noctilio F. into North America, there has been increased interest in the poorly-described native Siricidae communities. To date, few studies have surveyed specifically for Siricidae, and many reports of native siricid populations are byproducts of sampling efforts targeting Coleoptera. We report results from a survey targeted specifically at native and exotic Siricidae in Minnesota. We used Lindgren funnel traps from 2006 to 2008 baited with α/β-pinene (Sirex lure), ethanol (EtOH), EtOH + α-pinene, or Ips 3-part lures. We captured 704 native Siricidae comprising seven species, of which none were exotic. To our knowledge, this is one of the largest field collections of Siricidae from a single discrete set of localities in existence. Adult Siricidae began flying in June and continued into October each year. The α/β-pinene lure was most effective, but the EtOH + α-pinene lure was also moderately effective. We compare our data with those from several states and provinces in the Great Lakes Region of North America. Our data provide insight into the community composition of native Siricidae in Minnesota, while concurrently providing evidence that S. noctilio populations have not yet reached this far into the continental United States.     

DNA sequence and RFLP data reflect geographical spread and relationships of Amylostereum areolatum and its insect vectors

The white rot fungus, Amylostereum areolatum (Basidiomycetes), is best known for its symbiotic relationship with various siricid wood wasp species. In this study, the relationship between isolates of A. areolatum associated with two wood wasp species, Sirex noctilio and S. juvencus, are considered to identify possible intraspecific groups. Isolates from the northern (native) and southern (exotic) hemispheres are included to determine patterns of geographical spread and origin of introductions into the southern hemisphere. The phylogenetic relationships of these isolates to authentic isolates of A. chailletii, A. laevigatum and A. ferreum were also investigated. Sequence and restriction fragment length polymorphism (RFLP) analyses of the variable nuc-IGS-rDNA region provided markers to distinguish intraspecific groups within A. areolatum. Isolates of A. areolatum associated with S. noctilio and S. juvencus contained four heterogenic sequences in the DNA region analysed. These sequences occurred in one of five combinations in each isolate. Some of these sequences were unique to isolates of A. areolatum from either wasp species, while others were present in both groups. This shows the ancient and specialized evolutionary relationship that exists between these insects and fungi. Isolates from the southern hemisphere all share the same sequence group. This supports previous hypotheses that S. noctilio has spread between countries and continents of this region. At the interspecific level, the IGS-rDNA sequence analysis showed that A. ferreum and A. laevigatum are closely related to each other, and they in turn are related to A. chailletii. Amylostereum areolatum was the most distinctly defined species in the genus. This can be attributed to the obligate relationship between A. areolatum and its insect vectors. Polymerase chain reaction-RFLP analysis was also shown to be an effective tool to distinguish between the different species of Amylostereum.     

Test of nonhost angiosperm volatiles and verbenone to protect trap trees for Sirex noctilio (Hymenoptera: Siricidae) from attacks by bark beetles (Coleoptera: Scolytidae) in the northeastern United States

Sirex noctilio F. (Hymenoptera: Siricidae) is an invasive woodwasp, currently established in northeastern North America. In other regions of the world, stressed trap trees are used to monitor populations of S. noctilio and to provide inoculation points for the biological control nematode Deladenus siricidicola Bedding. However, the operational use of trap trees for S. noctilio in North America may be compromised by the large community of native organisms that inhabit stressed and dying pine trees. Common bark beetles such as Ips pini (Say) and Ips grandicollis (Eichhoff) (Coleoptera: Scolytidae) could potentially compete with S. noctilio and associates for resources on trap trees, possibly reducing the efficacy of trap trees as habitats for the woodwasp. In an attempt to develop a technology to mitigate this potential issue, three common semiochemical interruptants--conophthorin, green leaf volatile mix, and verbenone--were tested for effectiveness in reducing arrivals of I. pini and I. grandicollis on trap trees treated with herbicides in northeastern United States. In addition, the effects of these compounds were determined independently with pheromone-baited multiple-funnel traps. None of the interruptants reduced numbers of I. pini or I. grandicollis either arriving on trap trees or caught in pheromone-baited traps. However, verbenone increased catches of I. grandicollis in traps baited with its pheromone, ipsenol. The mix of green leaf volatiles reduced catches of a native ambrosia beetle, Gnathotrichus materiarius (Fitch), whereas verbenone reduced trap catches of an exotic ambrosia beetle, Xylosandrus germanus (Blandford). Catches of X. germanus in traps adjacent to trap trees were enhanced with conophthorin.     

松树蜂与其共生真菌的互利共生关系

松树蜂Sirex noctilio Fabricius是一种重要的国际林业检疫性害虫,主要危害针叶树,原产欧亚大陆和北非。近100多年来,先后入侵大洋洲(新西兰和澳大利亚)、南美洲(乌拉圭、阿根廷、巴西和智利)、北美洲(加拿大和美国),以及南非。2013年8月,在中国黑龙江省内首次发现松树蜂,目前发现其主要危害樟子松。松树蜂能与一种淀粉韧革菌属Amylostereum的真菌Amylostereum areolatum(Fr.)Boidin形成严格的互利共生关系,该虫除直接钻蛀树木外,还能通过产卵行为将自身毒素腺体分泌的毒素和体内共生真菌随同虫卵一起注入寄主树木体内,形成"虫-毒-菌"3个致害因子相互协作的特殊危害方式,加速树势的衰弱并造成寄主树木死亡。本文就国内外松树蜂与其共生菌互利共生关系的研究进行了综述,分别从结构与功能的层次上对其互利共生关系进行了梳理和总结,重点阐释了松树蜂与共生菌的营养共生关系,松树蜂携带传播共生菌的机制,共生菌的种群遗传学以及松树蜂毒素和共生菌在危害寄主树木时的协同关系等。以期为开展关于松树蜂的专项研究提供一些合理的建议,同时为积极有效地防控该害虫提供科学依据。     

STUDIES ON THE BIOLOGY OF RHYSSA PERSUASORIA (L.) (HYMENOPTERA: ICHNEUMONIDAE) INCORPORATING AN X-RAY TECHNIQUE

i
Development of the immature stages of Rhyssa persuasoria (L.) on the larvae, prepupae and pupae of Sirex noctilio F. was followed in situ in Pinus radiata D. Don. by an X-ray technique.
R. persuasoria females were allowed to oviposit in wood in which the location of immature stages of S. noctilio had been determined radiographically. By this means it was found that they could not locate their hosts with certainty. When a host was located the female parasite paralysed it by stinging and laid an egg upon it. The host was consumed within five weeks and the parasite passed through four larval instars before pupation.     

Putative origin of clonal lineages of Amylostereum areolatum, the fungal symbiont associated with Sirex noctilio, retrieved from Pinus sylvestris, in eastern Canada

The Eurasian Sirex noctilio-Amylostereum areolatum complex was discovered and has become established close to the North American Great Lakes in the 2000s. This invasive forest insect pest represents a very high risk to native and exotic pines in North America. We investigated the geographical origin of clonal lineages of the fungal symbiont A. areolatum in the recently pest-colonized eastern Canadian region by analyzing mitochondrial and nuclear sequence variations and comparing the genetic diversity of a worldwide collection of fungal symbionts among six countries where the Sirex complex is native and four countries from which the insect-fungal complex has been introduced. In total, 102 isolates were analyzed. While 12 multilocus genotypes (MLGs) are observed in the areas where S. noctilio is native, only two MLGs are retrieved from areas where S. noctilio is not native, indicating the wide spread of clonal lineages in the introduced fungal symbiont of S. noctilio. MLG2 comprises 26% of the Canadian isolates and is also observed in Chile and South Africa, where the insect-fungal complex has also been introduced. MLG3 comprises 74% of the Canadian isolates and is also observed in the USA, but nowhere else in our worldwide collection. Thus, at least one of the Canadian clonal lineages shares a common origin with A.?areolatum isolates from the Southern Hemisphere. The source of the second clonal lineage is still unknown, but phylogenetic analyses show that MLG3 is isolated. More extended sampling is necessary to determine the origin of this fungal clonal lineage and investigate its probable symbiotic association with native North American Sirex.     

Reproductive strategy of a woodwasp with no fungal symbionts, Xeris spectrum (Hymenoptera: Siricidae)

Experiments were conducted to elucidate the reproductive strategy of the siricid woodwasp, Xeris spectrum, which carries no substantial symbiotic fungi in its body, in a comparison with the life cycles of two fungus-carrying siricid woodwasp species, Sirex nitobei and Urocerus japonicus, by considering ecological traits such as seasonal patterns of occurrence, spatial distribution of emergence on a tree, and oviposition activities. Part of the X. spectrum populations emerged in spring, during May and June, while others emerged in summer, during August and September, simultaneously with other siricid fungus-carrying woodwasps. The vertical distribution pattern of X. spectrum emergence holes on the trunk closely coincided with the emergence hole pattern of S. nitobei. X. spectrum laid few eggs on fresh logs, old logs, or on logs inoculated with potato dextrose agar, whereas on logs inoculated with Amylostereum chailletii or A. areolatum, X. spectrum females oviposited no less than 30%, on average, of their potential eggs. Moreover, the oviposition sites on these logs were concentrated near the Amylostereum inoculation positions. These results indicate that X. spectrum has evolved a life history that utilizes fungal symbionts of other woodwasp species without itself possessing any symbiotic fungus. Moreover, X. spectrum has evolved a dual reproductive system in that (1) some adults emerge in summer during the same emergence period as the fungus-carrying woodwasps and thereby oviposit on host trees already inoculated with fungi, and (2) other adults emerge the next spring and oviposit on trees that were inoculated with fungi a year earlier. Received: 16 January 1997 / Accepted: 14 July 1997     

Host tissue identification for cryptic hymenopteran parasitoids associated with Sirex noctilio

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松树蜂毒腺转录组分析

【目的】构建入侵种松树蜂Sirex noctilio毒腺转录组数据库,筛选并分析松树蜂毒腺基因数据。【方法】采用新一代高通量测序平台Illumina HiSeq^TM 4000对松树蜂雌成虫毒腺进行转录组测序、数据组装和生物信息学分析。【结果】共获得12.7 Gb松树蜂雌成虫毒腺有效转录组数据,并组装到37 098条unigenes,平均长度968 bp,N50长度为2 364 bp。将所得的unigenes数据使用BlastX与各大数据库比对,共注释到13 515条unigenes,并且在NR数据库中注释的unigenes最多,共11 108条(占总数的29.94%),其中相似基因占比最高的物种为丽蝇蛹集金小蜂Nasonia vitripennis,达815条(占总数的7.29%)。在GO数据库中注释到5 726条unigenes,根据功能被分为生物学进程、细胞组分和分子功能3大类63个亚类。KEGG代谢通路分析表明,7 602条unigenes注释到357个代谢通路。根据基因注释信息进一步筛选到43条嗅觉相关基因,包括嗅觉受体(odorant receptor, Or)基因25条、化学感受蛋白(chemosensory protein, CSP)基因10条、离子型受体(ionotropic receptor, IR)基因5条和气味结合蛋白(odorant binding protein, OBP)基因3条。此外,还筛选出11条漆酶基因,包括漆酶1(laccase1, LAC1)基因5条、漆酶2(laccase2, LAC2)基因4条、漆酶4(laccase4, LAC4)基因1条和漆酶9(laccase9, LAC9)基因1条,且其中1条LAC2基因在所有被注释的基因中表达量最高(FPKM值=21 126)。【结论】本研究获得的松树蜂毒腺转录组数据为松树蜂毒液组分的鉴定和生物学功能的研究奠定了一定的理论基础。     

Effect of Two Bark Beetle-Vectored Fungi on the On-Host Search and Oviposition Behavior of the Introduced Woodwasp Sirex noctilio (Hymenoptera: Siricidae) on Pinus sylvestris Trees and Logs

Sirex noctilio’s fungal symbiont, Amylostereum areolatum, is required for its offspring’s development. The symbiont is a weak competitor with bark beetle-vectored fungi so it would be beneficial to the woodwasp if it avoided ovipositing in substrate colonized by these competitors. The response of S. noctilio to the presence of two beetle-vectored fungi, Leptographium wingfieldii and Ophiostoma minus, inoculated into living trees, and to L. wingfieldii and A. areolatum inoculated into cut logs was investigated. The wasp avoided areas with L. wingfieldii; there were fewer signs of oviposition activity and drilling in these zones. There was no significant response to O. minus or A. areolatum. Female woodwasps can detect the presence of some fungi and make choices about oviposition sites that benefit their offspring.     

松树蜂的产卵行为

【目的】研究松树蜂Sirex noctilio的产卵行为,明确其产卵能力,为评估其繁殖潜力和危害能力提供基础数据。【方法】于黑龙江省大庆市杜尔伯特蒙古族自治县新店林场采集被松树蜂危害的寄主樟子松Pinus sylvestris var.mongolica木段上获得虫源。在室内条件下观察和分析松树蜂产卵的行为过程及规律。解剖松树蜂在樟子松木段上的产卵孔,并观察其结构特征。【结果】松树蜂羽化时即性成熟,能够马上进行交配和产卵。松树蜂雌成虫一次完整的产卵过程主要分为4个动作:树皮钻孔、木质部钻刺、产卵(注入有毒黏液和共生真菌Amylosereum areolatum)和产卵器拔出。产卵时间在360～540 s之间的产卵频数最多,占产卵总频数的41.40%;产卵过程中木质部钻刺用时最长,至少占整个产卵过程用时的90%。松树蜂雌成虫在一个产卵孔处会进行1～4次产卵,产卵时间和产卵次数呈显著正相关,当产卵时间t<360 s时,进行了1次产卵;当360 s≤t<540 s时,进行了2次产卵;当540 s≤t<780 s时,进行了3次产卵;当t≥780 s时,进行了4次或更多次产卵。松树蜂在一个产卵孔处进行1, 2, 3和4次产卵的比例分别为21.66%, 41.40%, 27.39%和9.55%。【结论】松树蜂雌成虫在一个产卵孔处的产卵时间和产卵次数呈正相关。利用产卵时间和产卵次数的关系,在只调查产卵时间的情况下,可以推断产卵次数。松树蜂在一个产卵孔处产卵的次数多,对寄主樟子松危害大。     

Parasitism and dispersal potential of Sirex noctilio: implications for biological control

1 Sirex noctilio F. (Hymenoptera: Siricidae) is a wood‐boring wasp that attacks many pine species, including commercial trees planted throughout the world. Management of its populations is largely based on biological control using the nematode Beddingia siricidicola. Adult females are sterilized by the nematode, but are free to move and attack new trees, promoting nematode dispersal. Although generally successful, wasp management through nematode introductions has sometimes been inadequate. 2 We evaluated the effect of parasitism by B. siricidicola on flight performance of woodwasps under laboratory conditions. Using flight mills, we recorded a total of 46 flight trials over 23 h, obtained from infected and control (uninfected) females. 3 Although all wasps lost weight during flight, parasitized females were significantly smaller and suffered larger weight losses than uninfected females. In addition, total flight distance and velocity were lower in parasitized females. 4 Because nematode infection transmission relies on healthy wasps attacking trees previously visited by nematode‐bearing females, differential dispersal capacity could limit biological control success.     

Effects of previous defoliation on pine looper larval performance

1 During outbreaks of the pine looper, Bupalus piniarius, its host, Pinus sylvestris, is severely defoliated. The larvae of this geometrid normally feed on mature needles. However, because trees are totally defoliated during outbreaks, the next generation is forced to feed on current-year needles. 2 Bupalus piniarius larvae feeding on previously defoliated trees may show lower performance either because of induced resistance or because larvae have to feed on needles not normally fed upon (current instead of mature). 3 These hypotheses were tested in an experiment where larvae were reared on (i) shoots naturally defoliated the previous year, and thus, bearing only current-year needles, (ii) non-defoliated shoots where larvae had access only to current-year needles, and (iii) control shoots with access to both current and mature needles. 4 There was no support for the induction hypothesis. Survival was lower on naturally defoliated shoots than on control shoots (81.3 vs. 90.9%), but survival was lower also on non-defoliated shoots where larvae had access only to current-year needles (78.8%). Data on larval feeding distribution showed a strong preference for mature needles. 5 Needle nitrogen concentration of current-year needles was 38% higher on defoliated trees than on non-defoliated trees. 6 It is concluded that defoliation affected larval performance primarily through the removal of the preferred type of needles and not because of an induced resistance. Effects of increased concentrations of allelochemicals in defoliated shoots, if present, were probably cancelled out by increased nitrogen concentrations.     

Assessing the role of bark- and wood-boring insects in the decline of Scots pine (Pinus sylvestris) in the Swiss Rhone valley

Abstract.  1. In several dry inner Alpine valleys higher mortality levels of pine have been observed in recent years. This paper evaluates the role of xylophagous insects in the current pine decline and the influence of climate change on the infestation dynamics.
2. More than 200 trees of different levels of crown transparency (needle loss) were felled between 2001 and 2005 and sections of them incubated in insect emergence traps. Colonisation densities were related to the transparency level of each host tree at the time of attack.
3. Trees with more than 80% needle loss were colonised most frequently, but the breeding density was highest in trees with 65–80% needle loss.
4. The scolytine Ips acuminatus and the buprestid Phaenops cyanea colonised trees with 30–90% needle loss in high densities. The bark beetle Tomicus minor was less aggressive, preferring trees with 60–85% needle loss. The hymenopteran Sirex noctilio and the cerambycid Acanthocinus aedilis were restricted to greatly weakened trees with 50–85% needle loss. Most species colonised trees that had experienced a decline in vigour, that is an increase in crown transparency shortly before attack.
5. The infestation dynamics of P. cyanea covaried with the drought index as well as with temperature.
6. Increased temperatures not only trigger a drought stress rendering the host trees susceptible to insect attack, but also accelerate insect development. As more frequent drought periods are likely as a result of climate change, even trees only slightly or temporarily weakened will be more subject to attack by aggressive species such as I. acuminatus and P. cyanea .     

Trunk cutting initiates bottom-up cascades in a tri-trophic system: sprouting increases biodiversity of herbivorous and predaceous arthropods on willows

We examined the effects of trunk cutting on the regrowth responses of two dominant willow species, Salix eriocarpa and S. gilgiana , and the subsequent effects on the community structure (abundance and species richness) of herbivorous and predaceous arthropods. We studied ten randomly selected pairs of cut and uncut (control) trees of each willow species. Field observations showed that when the trunks were cut, shoots sprouted from the base and developed rapidly. These shoots continued to grow until July, producing lateral shoots and leaves, whereas current-year shoots on uncut trees essentially stopped growing by April. In July, the upper leaves of cut trees were less tough and had a greater water and nitrogen content than leaves of uncut trees. Leaf consumption and abundance and species richness of both herbivorous and predaceous arthropods were significantly greater on cut trees than on uncut trees in both willow species. Overall, trunk cutting resulted in at least a two-fold increase in both relative abundance and species richness within the arthropod community on the willow species. We concluded that the severe physical damage caused by trunk cutting greatly increased the biodiversity of herbivorous and predaceous arthropods through bottom-up cascading effects.     

Alterations of chemical composition,construction cost and payback time in needles of Masson pine (Pinus massoniana L.) trees grown under pollution

Previous studies show that Masson pine (Pinus massoniana L.) stands grown at the industrially-polluted site have experienced unprecedented growth decline, but the causal mechanisms are poorly understood. In this study, to understand the mechanisms of growth decline of Mason pine strands under pollution stresses, we determined the reactive oxygen species levels and chemical composition of the current-year (C) and one-year-old (C + 1) needles, and calculated the needle construction costs (CC_mass) of Masson pine trees grown at an industrially-polluted site and an unpolluted remote site. Pine trees grown at the polluted site had significantly higher levels of hydroxyl radical and superoxide anion in their needles than those grown at the unpolluted site, and the former trees eventually exhibited needle early senescence. The contents of lipids, soluble phenolics and lignins in C and C + 1 needles were significantly higher at the polluted site than at the unpolluted site, but the total amounts of non-construction carbohydrates were lower in non-polluted needles than in polluted needles. Elevated levels of the reactive oxygen species and early senescence in polluted needles together led to significant increases in CC_mass and a longer payback time. We infer that the lengthened payback time and needle early senescence under pollution stress may reduce the Masson pine tree growth and consequently accelerate tree decline.