Introduction and establishment of parasitoids for the biological control of the apple ermine moth, Yponomeuta malinellus (Lepidoptera: Yponomeutidae), in the Pacific Northwest

Four parasitoids were imported from five countries in Eurasia and released in northwestern Washington, US, to control the apple ermine moth (AEM), Yponomeuta malinellus Zeller, which colonized the Northwest around 1981. From 1988 to 1991, 95,474 individuals of Ageniaspis fuscicollis (Dalman) from France, China, Korea, and Russia were released in Washington. Parasitism of AEM increased 4- to 5-fold over that produced by preexisting natural enemies between 1989 and 1994 at 22 monitored sites. Subsequently, the wasp dispersed up to 20 km from release sites. A. fuscicollis also parasitized the cherry ermine moth, Yponomeuta padellus (L.), which was discovered in the Pacific Northwest in 1993. A total of 1813 individuals of Herpestomus brunnicornis (Gravenhorst) from France, Korea, and Japan were released in 1989–1991, and 26 wasps were recovered in 1994–1995. From 1989 to 1991, 2647 Diadegma armillata (Gravenhorst) individuals from France were released. D. armillata was recovered at one site in 1991 two months following release, but no other recoveries have been made. A total of 8274 Eurystheae scutellaris(Robineau-Desvoidy) individuals were released in 1989 to 1991. However, this tachinid has not been recovered. A consistent decline of AEM populations occurred in 1989–1995, including at sites where A. fuscicollis was not recovered, suggesting other factors also contributed to this pest’s decline. Now well established in western Washington, A. fuscicollis may help suppress future outbreaks of Y. malinellus and its congener, Y. padellus.     

Avian disease at the Salton Sea

A review of existing records and the scientific literature was conducted for occurrences of avian diseases affecting free-ranging avifauna within the Salton Sea ecosystem. The period for evaluation was 1907 through 1999. Records of the U.S. Department of Agriculture, Bureau of Biological Survey and the scientific literature were the data sources for the period of 1907–1939. The narrative reports of the U.S. Fish and Wildlife Service's Sonny Bono National Wildlife Refuge Complex and the epizootic database of the U.S. Geological Survey's National Wildlife Health Center were the primary data sources for the remainder of the evaluation. The pattern of avian disease at the Salton Sea has changed greatly over time. Relative to past decades, there was a greater frequency of major outbreaks of avian disease at the Salton Sea during the 1990s than in previous decades, a greater variety of disease agents causing epizootics, and apparent chronic increases in the attrition of birds from disease. Avian mortality was high for about a decade beginning during the mid-1920s, diminished substantially by the 1940s and was at low to moderate levels until the 1990s when it reached the highest levels reported. Avian botulism (Clostridium botulinum type C) was the only major cause of avian disease until 1979 when the first major epizootic of avian cholera (Pasteurella multocidia) was documented. Waterfowl and shorebirds were the primary species affected by avian botulism. A broader spectrum of species have been killed by avian cholera but waterfowl have suffered the greatest losses. Avian cholera reappeared in 1983 and has joined avian botulism as a recurring cause of avian mortality. In 1989, avian salmonellosis (Salmonella typhimurium) was first diagnosed as a major cause of avian disease within the Salton Sea ecosystem and has since reappeared several times, primarily among cattle egrets (Bubulcus ibis). The largest loss from a single epizootic occurred in 1992, when an estimated 155000 birds, primarily eared grebes (Podiceps nigricollis), died from an undiagnosed cause. Reoccurrences of that unknown malady have continued to kill substantial numbers of eared grebes throughout the 1990s. The first major epizootic of type C avian botulism in fish-eating birds occurred in 1996 and killed large numbers of pelicans (Pelecanus occidentalis & P. erythrorhynchos). Avian botulism has remained as a major annual cause of disease in pelicans. In contrast, the chronic on-Sea occurrence of avian botulism in waterfowl and shorebirds of previous decades was seldom seen during the 1990s. Newcastle disease became the first viral disease to cause major bird losses at the Salton Sea when it appeared in the Mullet Island cormorant (Phalacrocorax auritus) breeding colony during 1997 and again during 1998.     

Genotype and environment interact to influence acceptability and suitability of white spruce for a specialist herbivore, Zeiraphera canadensis

Abstract.

• 1 The independent and interacting effects of plant genotype and site (i.e. environment) on the acceptability of white spruce, Picea gluaca (Moench) Voss, to the spruce bud moth, Zeiraphera canadensis Mut. & Free. and on plant suitability for egg development, were studied at four sites in New Brunswick, Canada.
• 2 A greater proportion of shoots on trees in two half-sib families, previously designated as highly susceptible, were partially eaten by spruce bud moths than shoots on trees in two half-sib families with low susceptibility.
• 3 At the site with the highest bud moth population, oviposition was highest on trees in susceptible families and on branches damaged by bud moth larvae. Oviposition was not higher on trees in susceptible families at the other three sites, resulting in a strong tree genotype × site interaction for oviposition.
• 4 Although there was a significant tree genotype × site interaction for egg predation, egg survival was higher on trees in susceptible families at all sites, due to lower levels of egg parasitism and predation.
• 5 Egg densities were positively but weakly correlated to shoot length and diameter. There were no consistent relationships between shoot length, shoot diameter, needle length or needle density and per cent egg survival, parasitism or predation.
• 6 Because egg survival was higher on trees in susceptible families at all sites but egg densities were only higher on trees in susceptible families at one site, host plant acceptability and suitability were positively related at only one site. We speculate that Z.canadensis does not distinguish between hosts of different suitability until trees are heavily damaged.

     

Biological control of parthenium (Parthenium hysterophorus): the Australian experience

ABSTRACT

Parthenium is a Weed of National Significance in Australia. Biological control of parthenium in Australia commenced in 1977 and since then nine insect species and two rust fungi have been introduced and established. Seven of them are widespread, however the time taken for field establishment varied widely between various agents, ranging from one to 15 years. Among them, the stem-galling Epiblema moth, the stem-boring Listronotus weevil, the seed-feeding Smicronyx weevil and the root-feeding Carmenta moth occur in all parthenium-infested areas at high population densities. The leaf-feeding Zygogramma beetle occurs only in central and southern Queensland, and not in northern Queensland. The parthenium summer rust occurs seasonally in central and northern Queensland, while the parthenium winter rust is more widespread in southern Queensland than in central Queensland, but does not occur in north Queensland. The sap-feeding Stobaera planthopper and the leaf-mining Bucculatrix moth established and are widespread, but their damage levels remain very low. The stem-galling Conotrachelus weevil and the stem-boring Platphalonidia moth are believed to be established, but at very low abundance. Biological control has resulted in significant reductions in the abundance and impact of parthenium in Australia. As a result, the area infested with parthenium in central Queensland has declined since the mid-1990s. Due to the absence of many of the effective agents in southern and south-eastern Queensland, agents from central Queensland are being redistributed there. Additionally, based on Australian success, many of these agents have also been introduced into other countries around the world.     

Releases of Trichogramma platneri (Hymenoptera: Trichogrammatidae) in Apple Orchards under a Sterile Codling Moth Release Program

Based on the premise that augmented host numbers may help multiply and support parasitoid populations, the egg parasitoid Trichogramma platneri Nargarkatti was released in apple orchards which were participating in a sterile codling moth, Cydia pomonella (L.), release program. Nonviable eggs resulting from matings involving at least one sterile codling moth partner can be successfully parasitized by T. platneri. Grain moth-reared, as well as codling moth-reared, T. platneri were released either in the spring or in the spring and summer oviposition period(s) of wild codling moth. Sentinel codling moth eggs were hung weekly, for 3-day periods, from May until September to determine fluctuations in T. platneri populations both during and between releases. Low numbers of wild or nonviable codling moth eggs or other susceptible host eggs resulted in sufficient eggs to maintain low spring- or summer-introduced T. platneri populations. T. platneri reduced codling moth damage in trees in which the Trichogramma were released.     

Hemiptelea mikii sp. nov. (Ulmaceae), fossil fruits and woods from the pleistocene of central Japan

A new fossil species,Hemiptelea mikii, is described on the basis of fruits from the Pleistocene of central Japan. It is distinguished fromH. davidii, the only extant species of the genus restricted to Korea and China, in having shorter fruits. Fossil woods discovered from the same horizon differ from the extant one in some anatomical characteristics, and are assigned to the new fossil species. Taken together with earlier records of fossil fruit occurrence in the early and the middle Pleistocene of central Japan, the latest finding of fossil fruits and woods from the last glacial sediments (ca. 50,000 years ago) at Kita-egota site of Tokyo suggests thatH. mikii was widespread in central Japan throughout the Pleistocene and survived until as late as the Last Glacial age.     

Moth outbreaks in relation to oak masting and population levels of small mammals: an alternative explanation to the mammal-predation hypothesis

The relationship between population outbreaks of the gypsy moth (Lymantria dispar) and oak masting in North America has been interpreted as an effect of reduced predation on moth pupae from small mammals after years of acorn failure. However, moth defoliation could be a consequence of high acorn production rather than of acorn failure, as all moth outbreaks in two time series presented by Liebhold et al. [Popul Ecol (2000) 42:257–266] were reported shortly after mast years. A similar pattern has been found for the green oak leaf roller moth (Tortrix viridana) in southern Norway. Because predation from small mammals should be less important for the latter species, I argue that the acorn-moth relationships are most likely caused by mast-induced changes in the chemical composition of oak leaves. Given the high number of eggs laid by each moth female, there is a huge potential for population growth in or shortly after a mast year if larval survival is no longer limited by low food quality.     

Managing lepidopteran pests in cabbage with herbicide-induced resistance, in combination with a pyrethroid insecticide

S-ethyldipropylthiocarbamate (EPTC) applied as a soil treatment or over-the-top spray on cabbage plants (Brassica oleracea L.) caused the leaves to turn ‘glossy’ for as long as 30 days. EPTC-induced glossy plants were damaged significantly less than untreated plants by diamondback moth,Plutella xylostella (L.), imported cabbage worm,Pieris rapae (L.), and cabbage looper,Trichoplusia ni (Hbn.). Reductions in damage were equivalent to those obtained from treatment with permethrin. When used in combination with permethrin, EPTC provided additive control of damage by these pests. Our calculations show EPTC-induced resistance to be cost-effective. This use of EPTC has several limitations, however. Younger plants (<9 leaves) were killed or injured by the herbicide. The growth of older plants was not affected, but plants did not become glossy for ca. 10 days after they were treated with EPTC. The crop must be protected with insecticides until the plants are mature enough to treat with EPTC, and until treated plants become glossy. In addition, since the glossy trait is only effective against first instar larvae, populations of later instars on glossy plants must be reduced with an application of insecticide. Finally, EPTC formulations are water-soluble and can be washed away from the plants by heavy rains and irrigation, which may make this use of EPTC impractical in some situations. Where its use is practical, and the indicated precautions are taken, EPTC-induced resistance could reduce dependence on chemical insecticides and reduce selection for insecticide resistance in diamondback moth.     

Establishment and Dispersal ofUrophora affinis(Diptera: Tephritidae) andMetzneria paucipunctella(Lepidoptera: Gelechiidae) in Southwestern Virginia

Two European gall-producing insects,Urophora affinisFrfld. (Diptera: Tephritidae) andMetzneria paucipunctella(Zeller) (Lepidoptera: Gelechiidae) were introduced into Virginia in 1986 for biological control of spotted knapweed (Centaurea maculosaLam.). Adults ofU. affinis(n = 2625) andM. paucipunctella(n = 450) were released at two sites in Montgomery County, Virginia, and their populations were monitored yearly by dissecting spotted knapweed flower heads. Beginning in 1992, knapweed samples collected at various distances from the release sites were checked for dispersal.U. affinisis well established and is spreading slowly. The number of larvae per flower head and the seed numbers are inversely related as plants with the greatest number of larvae per spotted knapweed head had the lowest number of seeds. Knapweed density has declined at one of the release sites which had the highest rate of infestation byU. affinis.Establishment of the moth,M. paucipunctella,is less certain as it has been recovered at a very low level from only one site.     

The biomass of an Indian monsoonal wetland before and after being overgrown with Paspalum distichum L.

Paspalum distichum L. has been the dominant species in the monsoonal wetlands of the Keoladeo National Park in northcentral India since 1982 when grazing by water buffalo and domestic cattle was halted. Maximum water levels in these wetlands occur immediately after the end of the summer monsoon in late September of early October and then decline until the next summer monsoon the following June. After the normal 1985 monsoon, maximum water depths were around 140 cm. After the poor 1986 monsoon, maximum water depths were only around 60 cm. Paspalum distichum maximum aboveground biomass at four sites ranged from 850 g m^-2 at the shallowest site to 3400 g m^–2 at a deep water site. The maximum biomass of other vegetation types, which had dominated this wetland prior to 1982, ranged from 1400 g m^-2 at a deep water site (Ipomoea aquatica Forsk.) to only 240 g m^-2 to 400 g m^-2 at a deep-water submersed site (Hydrilla verticillata (L. f.) Royle/Cyperus alopecuroides Rottb.) and at a shallow emergent site (Scirpus tuberosus Desf./Sporobolus helvolus (Trin.) Dur. et Schinz). For all vegetation types, biomass changed seasonally in response to changing water levels and temperatures. After the 1986 monsoon, above-ground biomass for all vegetation types was much lower than it had been after the 1985 monsoon. Mean below-ground biomass was very low in all vegetation types (1 to 47 g m^-2). Paspalum distichum had a higher aboveground biomass at nearly all water depths in all seasons than that of the pre-1982 vegetation types. Paspalum distichum belowground biomass, however, is comparable to, or less than, that of the pre-1982 vegetation types. During years with an average monsoon, the overall primary production of these wetlands is estimated to have increased 2.5 to 3.5-fold since they were overgrown with Paspalum distichum.     

Changes in the Alyki Kitrous wetland in northern Greece: 1990–1999, and future prospects

The Alyki wetland in northern Greece is a site of notable herpetological and ornithological importance. A large population of the tortoise Testudo hermanni began to recover slowly (r = 0.016) between 1990 and 1999, following catastrophic habitat destruction in 1980 and slow decline from 1980–1990. Heathland vegetation showed signs of desiccation, probably due to increased drainage by the salt works, including deterioration of Crataegus, Ruscus and Asphodelus, and loss of formerly important food plants of tortoises. Activity and body mass condition of tortoises were reduced in summer in grassy heath habitats. Predation of artificial (chicken egg) tortoise nests increased, and the relative frequency of juveniles (about 1 % of samples) was lower than after severe habitat destruction or pesticide damage. These changes were attributed to an increasing population of badgers, Meles meles. Population levels of waders were lower in 1998/1999 than in 1988/1989, especially avocets (Recurvirostra avosetta) for which the site was internationally important. Breeding populations of most waders and larids also declined. Mediterranean gulls, for which Alyki was formerly the most important breeding area outside Russia, did not nest from 1990 to 1998, and nests were unsuccessful in 1999. Changes in breeding populations were due to falling lagoon levels, exposure to predators and vegetation encroachment on islet breeding sites. Midwinter waterfowl populations remained high or increased, however, as alternative feeding areas were available in the lagoon. Preservation of the habitats against development of the salt works and increasing desiccation are necessary to maintain the long-term conservation value of the Alyki site.     

Resources and dispersal as factors limiting a population of the tussock moth (Orgyia vetusta), a flightless defoliator

The western tussock moth (Orgyia vetusta) is very abundant on one stand of bush lupine (Lupinus arboreus) at the Bodega Marine Reserve (Sonoma Co, Calif., USA), but is sparse or absent on nearby stands. To determine what controls its abundance, both within the outbreak area and more globally, I performed experimental manipulations of resource availability and dispersal. To measure resource limitation, I inoculated 30 caged and 30 uncaged bushes with a realistic range of numbers of tussock moth eggs. On caged bushes, starvation led to density-dependent reductions in survival, pupal weight and fecundity. Larvae on uncaged bushes experienced density-independent ant predation on early instars and density-dependent emigration by late instars. From the results of this experiment, I predicted the density of a resource-limited tussock moth population. The predictions agreed fairly well with data from the outbreak area in 1992. To measure dispersal by the moth, which has flightless adult females, I released 30,000 tussock moth eggs at a central point in each of two uninfested lupine stands, and censused larvae weekly in a circle of radius 16 m until pupation. Median displacement over one entire generation was only 2 m, or about 2 bush radii. Rearing experiments indicated that bushes outside the out-break area are fully nutritionally suitable for the moth. I conclude that two major factors limiting the population are resources (within the outbreak area) and inefficient dispersal (more globally).     

Seasonal and cultivar-associated variation in oviposition preference of Oriental fruit moth (Lepidoptera: Tortricidae) adults and feeding behavior of neonate larvae in apples

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia ponmonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth.     

孟连苞叶兰(兰科)的重新发现与形态特征增补

孟连苞叶兰(Brachycorythis menglianensis)自2001年发表以来,再也没有被发现和记录过。由于能够用于分类学参考的仅为模式标本和依据标本绘制的素描图,加之原始文献的描述不够细致,以致于Henrik Æ Pedersen将其作为长叶苞叶兰(B. henryi)的异名处理。时隔十五年后,我们在该种的模式产地进行野外兰科植物考察时,有幸重新发现了该种。通过对其新鲜带花植株的详细比对之后,发现孟连苞叶兰与长叶苞叶兰在形态上具有明显的差异,如孟连苞叶兰叶片卵圆形,叶片大小(2.5- 4.7 × 1.7-2.3 cm)、唇瓣密被疣状突起且先端缺刻或2裂等特征,明显有别于长叶苞叶兰。因此,在该研究中支持孟连苞叶兰的分类学地位,同时对该种的形态特征、生境以及生存现状等信息进行了增补。     

The photosensitivity of the malate oxidase system of a pigmented strain and a carotenoidles mutant of Sarcina lutea (Micrococcus luteus)

The effect of white light on the malate oxidase of Sarcina lutea (Micrococcus luteus) membranes has been examined using a carotenoid-containing and a carotenoidless mutant. At least three photosensitive sites have been detected. Two of these are associated with the malate dehydrogenase complex (malate-menaquinone reductase) and are unaffected by membrane carotenoid. A third site which has been detected beyond the dehydrogenase complex, is protected by carotenoid since it can only be demonstrated in carotenoidless systems. A repair mechanism has been found for one of the two sites in the dehydrogenase complex.     

Reduction in size and fecundity of the autumnal moth, <Emphasis Type="Italic">Epirrita autumnata</Emphasis>, in the increase phase of a population cycle

Increasing fecundity with increasing density has been observed for many cyclic herbivore populations, including some forest Lepidoptera. We monitored population density, body size and reproductive capacity of the cyclic lepidopteran, the autumnal moth (Epirrita autumnata, Geometridae), from the early increase phase to the devastating outbreak density in northernmost Norway. Larval density of the species increased exponentially from 1998 to 2002 and remained at the outbreak level also in 2003. Within the same period, the body size and fecundity of individuals reduced as analysed from several parallel datasets on larvae, pupae and adults. In another study area in northernmost Finland, the density increase of the autumnal moth was moderate only, and true outbreak density was not attained during the study. Despite that, a reduction was again detected in the size and fecundity of individuals. Possible factors responsible for the reduced size and fecundity of individuals in the Norwegian population were quantitative shortage of foliage, rapid and delayed inducible resistances of the host, mountain birch (Betula pubescens ssp. czerepanovii), as well as crowding-induced responses of larvae. These factors likely acted in concert, although non-delayed responses to the density were emphasized. Our findings did not support the hypotheses of climatic release, inducible susceptibility of the host tree and mast depression (i.e. lowered chemical defence of the host tree after its mast seeding) as promoters of the fecundity-based density increase of the autumnal moth, since the reduced fecundity in relation to increased density was strongly against the predictions of these hypotheses. Therefore, we suggest that the density increase of autumnal moth populations is promoted by high survival rather than exceptionally high fecundity.     

Endophytic nitrogen fixation in sugarcane: present knowledge and future applications

In Brazil the long-term continuous cultivation of sugarcane with low N fertiliser inputs, without apparent depletion of soil-N reserves, led to the suggestion that N₂-fixing bacteria associated with the plants may be the source of agronomically significant N inputs to this crop. From the 1950s to 1970s, considerable numbers of N₂-fixing bacteria were found to be associated with the crop, but it was not until the late 1980s that evidence from N balance and ¹⁵N dilution experiments showed that some Brazilian varieties of sugarcane were able to obtain significant contributions from this source. The results of these studies renewed the efforts to search for N₂-fixing bacteria, but this time the emphasis was on those diazotrophs that infected the interior of the plants. Within a few years several species of such `endophytic diazotrophs' were discovered including Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, H. rubrisubalbicansand Burkholderia sp. Work has continued on these endophytes within sugarcane plants, but to date little success has been attained in elucidating which endophyte is responsible for the observed BNF and in what site, or sites, within the cane plants the N₂ fixation mainly occurs. Until such important questions are answered further developments or extension of this novel N₂-fixing system to other economically important non-legumes (e.g. cereals) will be seriously hindered. As far as application of present knowledge to maximise BNF with sugarcane is concerned, molybdenum is an essential micronutrient. An abundant water supply favours high BNF inputs, and the best medium term strategy to increase BNF would appear to be based on cultivar selection on irrigated N deficient soils fertilised with Mo.     

Reproductive biology and responses to threats and protection measures of the total population of a Critically Endangered Galápagos plant,Linum cratericola (Linaceae)

We describe a reproductive and population dynamic study of the total population of a Critically Endangered plant over 10 years, during which part of the population was protected from the main threat, feral ungulates. Linum cratericola (Linaceae) was first discovered in 1966 at two sites on Floreana Island, Galápagos. It has since disappeared from one site and survives in three groups of plants at the other, where it has been threatened with extinction by introduced ungulates and invasive plants. Population size, and growth rate and mortality of individual plants, have been monitored since 1997. The population appears highly responsive to changes in threat levels: the three plant groups increased rapidly following protection by fencing and ungulate control, but temporarily declined when feral goat pressure increased and during dry periods. Natural factors that may contribute to population limitation include dry years, grazing by native snails and competition from native vascular plants and cryptogams. Linum cratericola has a single flowering period per year and produces abundant seed with 28% germination after scarification, but with no obvious adaptations for long‐distance dispersal. Potential pollinators included the butterfly Leptotes parrhasioides, the hoverfly Toxomerus crockeri and the carpenter bee Xylocopa darwinii, all endemic to Galápagos. The continued survival of L. cratericola in the wild depends on effective protection from introduced herbivores and invasive plants. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 89–102.     

Why the larch bud-moth cycle collapsed in the subalpine larch-cembran pine forests in the year 1990 for the first time since 1850

The larch bud-moth cycle has been observed in the sub-alpine larch-cembran pine forests 16 times since 1850. Infestation is easily recognized by the characteristic red-brown discoloration of the larch crowns due to the wasteful feeding of the bud moth larvae. The heaviest defoliation recurs at intervals of 8.47±0.27 (SE) years, and the larval density per kilogram of larch branches varies more than 10000-fold over four or five generations. The basic regulatory mechanism for this cycle is the induced change in food quality for the two or more subsequent larval generations. Defoliation functions as a negative feedback mechanism acting on larval density. In 1989 local discoloration in the Upper Engadine valley was observed in the usual first focus. In 1990 and 1991, however, instead of the expected widespread defoliation damage, larval densities decreased drastically. Based on extensive field data collected from 1961 to 1991 on the development and the survival of the bud moth (Zeiraphera diniana Gn.) and the phenology of the host, Larix decidua L., this paper shows the effect of weather on survival in the egg stage and on the coincidence of larval hatching with the sprouting of the larch. It is shown that the winter and spring weather conditions in 1989–1991 were conducive to unusually high egg mortality. Since these conditions occurred in three successive generations, population growth was effectively reduced and the cycle collapsed prematurely. Thus the rather persistent cyclicity of the larch-larch bud-moth system was disturbed by weather conditions with a very low probability of occurrence, but due to the inherent high resilience of the system, the next population peak with visible defoliation is expected to occur 1996/1997, provided that the weather conditions return to the climatic standard.     

Moth pollination of woody species in the Cerrados of Central Brazil: a case of so much owed to so few?

We present a survey of moth pollination in woody species of the Cerrado of Central Brazil. Although with the exception of Roupala montana (which has simple polysepalous flowers arranged in dense cymes) all moth pollinated species in this community have tubular flowers, or a pseudo-tube formed from a single folded petal in Qualea grandiflora, settling moth flowers (tube less than 15 mm) vs. hawkmoth flowers (tube more than 50 mm) are markedly different in size. Moths visit some 20 woody Cerrado species, but they are probably effective pollinators of only 13 species or ca.14% of the woody taxa studied, and even in these latter species they are often very sparse visitors. Nevertheless, it is notable that moths are pollinators for 21% of the 38 most commonly distributed woody Cerrado species. Moreover, the reproductive efficacy of the studied moth pollinated species was similar to that of species pollinated by other kind of vectors.