Overwintering Sites Research Articles

Overwintering ofCulex pipiens pallens(Diptera: Culicidae) in Shandong, China

Abstract Culex pipiens pallens Coquillet can spread various mosquito-borne infectious diseases. This study identifies the overwintering sites and physiological condition of Cx. pipiens during hibernation in Shandong Province of P.R. China. Results show that female adult Cx. pipiens overwinter in habitats characterized by warm temperature, high humidity, and calm winds. Cellars yielded the highest densities, followed by air-raid shelters, caliducts, sewers, mountain caves, wells, stone caverns, etc. The adult density among overwintering sites differed significantly (F = 45.88, P < 0.01). Larvae and pupae were not captured after late December. In early winter, multiparous and bloodsucking mosquitoes accounted for a large proportion of the observed populations. However, their numbers gradually decreased as winter progressed, mainly due to their relatively high death rate in winter. Most mosquitoes overwinter in a state of diapause, and females have usually mated. Collections in midwinter showed that of thos...

Experience drives innovation of new migration patterns of whooping cranes in response to global change.

Anthropogenic changes in climate and land use are driving changes in migration patterns of birds worldwide. Spatial changes in migration have been related to long-term temperature trends, but the intrinsic mechanisms by which migratory species adapt to environmental change remain largely unexplored. We show that, for a long-lived social species, older birds with more experience are critical for innovating new migration behaviours. Groups containing older, more experienced individuals establish new overwintering sites closer to the breeding grounds, leading to a rapid population-level shift in migration patterns. Furthermore, these new overwintering sites are in areas where changes in climate have increased temperatures and where food availability from agriculture is high, creating favourable conditions for overwintering. Our results reveal that the age structure of populations is critical for the behavioural mechanisms that allow species to adapt to global change, particularly for long-lived animals, where changes in behaviour can occur faster than evolution.

Housekeeping by lodgers: the importance of bird nest fauna on offspring condition

Bird nests are designed to contain and protect parents, eggs and nestlings and to facilitate optimal safety and climatic conditions from egg-laying to fledging offspring. Bird nests also provide optimal conditions for a rich and diverse community of mainly invertebrates, who use nests as a foraging site, shelter, hiding place and reproduction and overwintering site. So far, no study has experimentally examined the impact of other nest inhabitants, except for parasites, on nestling development. The aim of this study was to investigate the impact of a saprophagous fly larvae Fannia spp. on nestling European Bee-eaters (Merops apiaster). We hypothesize that, if Fannia spp. larvae improve nest sanitation due to their detritivorous habits, increased larvae abundance would result in improved chick growth and health. Thus, to investigate the impact of Fannia spp. larvae on nestling Bee-eaters, we experimentally manipulated their abundance during the early nestling period and determined parameters indicative for nestling body condition and health. The experiment confirmed our prediction and revealed that increasing the number of saprophagous fly larvae had a positive effect on offspring condition. We suggest that bird nest fauna other than parasites might be as important and could be used as a model for ecosystem analyses. Bird nests usually constitute small, temporary ecosystems, which could facilitate investigation of aspects of ecosystem functioning.

PM 7/60 (2) Pantoea stewartii subsp. stewartii

Specific scopeThis Standard describes a diagnostic protocol for Pantoea stewartii subsp. stewartii.Specific approval and amendmentApproved in 2005‐09.Revised in 2016‐04.

Risk analysis of H5N1 highly pathogenic avian influenza in poultry at the Poyang Lake area, China

Migratory birds have been known to spread the highly pathogenic avian influenza virus (HPAIV) H5N1 over large distances. Moreover, previous studies have shown it to be widely circulated in live-bird markets. However, how live-bird markets in addition to wild birds affect the local persistence of avian influenza virus (AIV) remains uncertain. The abundance of fresh water and widely distributed wetlands make the Poyang lake area a suitable overwintering site for migratory birds. The intensive local poultry industry and poor biosecurity potentially increase the risk of interactions between the wild and domestic birds. These factors likely contributed to the spread and persistence of AIVs in the Poyang lake area in these years. Here, a cross-sectional survey together with sampling was conducted randomly in the Poyang lake area to investigate the local distribution of the H5N1 viruses. In total, 891 poultry isolates from 31 villages around the Poyang lake area were randomly sampled in poultry sectors and tested for the presence of avian influenza using RT-PCR assays. Environmental factors such as poultry density, road accessibility, and wild bird biodiversity together with breeding characteristics derived from these questionnaires were collected and utilized for risk analysis modelling. Our results revealed that distance to the nearest wetlands with a high number of birds and accessibility by road were the main risk factors for the occurrence HPAIV H5N1, suggesting that the high density of road networks may facilitate the transmission of this virus. Investigating the regional distribution characteristics of the virus is of great significance, therefore the general public would benefit from an early warning, prevention, and taking control measures in high-risk regions.

Linking the continental migratory cycle of the monarch butterfly to understand its population decline

Threats to several of the world's great animal migrations necessitate a research agenda focused on identifying drivers of their population dynamics. The monarch butterfly is an iconic species whose continental migratory population in eastern North America has been declining precipitously. Recent analyses have linked the monarch decline to reduced abundance of milkweed host plants in the USA caused by increased use of genetically modified herbicide‐resistant crops. To identify the most sensitive stages in the monarch's annual multi‐generational migration, and to test the milkweed limitation hypothesis, we analyzed 22 years of citizen science records from four monitoring programs across North America. We analyzed the relationships between butterfly population indices at successive stages of the annual migratory cycle to assess demographic connections and to address the roles of migrant population size versus temporal trends that reflect changes in habitat or resource quality. We find a sharp annual population decline in the first breeding generation in the southern USA, driven by the progressively smaller numbers of spring migrants from the overwintering grounds in Mexico. Monarch populations then build regionally during the summer generations. Contrary to the milkweed limitation hypothesis, we did not find statistically significant temporal trends in stage‐to‐stage population relationships in the mid‐western or northeastern USA. In contrast, there are statistically significant negative temporal trends at the overwintering grounds in Mexico, suggesting that monarch success during the fall migration and re‐establishment strongly contributes to the butterfly decline. Lack of milkweed, the only host plant for monarch butterfly caterpillars, is unlikely to be driving the monarch's population decline. Conservation efforts therefore require additional focus on the later phases in the monarch's annual migratory cycle. We hypothesize that lack of nectar sources, habitat fragmentation, continued degradation at the overwintering sites, or other threats to successful fall migration are critical limiting factors for declining monarchs.

Understanding a migratory species in a changing world: climatic effects and demographic declines in the western monarch revealed by four decades of intensive monitoring.

Migratory animals pose unique challenges for conservation biologists, and we have much to learn about how migratory species respond to drivers of global change. Research has cast doubt on the stability of the eastern monarch butterfly (Danaus plexippus) population in North America, but the western monarchs have not been as intensively examined. Using a Bayesian hierarchical model, sightings of western monarchs over approximately 40years were investigated using summer flight records from ten sites along an elevational transect in Northern California. Multiple weather variables were examined, including local and regional temperature and precipitation. Population trends from the ten focal sites and a subset of western overwintering sites were compared to summer and overwintering data from the eastern migration. Records showed western overwintering grounds and western breeding grounds had negative trends over time, with declines concentrated early in the breeding season, which were potentially more severe than in the eastern population. Temporal variation in the western monarch also appears to be largely independent of (uncorrelated with) the dynamics in the east. For our focal sites, warmer temperatures had positive effects during winter and spring, and precipitation had a positive effect during spring. These climatic associations add to our understanding of biotic-abiotic interactions in a migratory butterfly, but shifting climatic conditions do not explain the overall, long-term, negative population trajectory observed in our data.

Effects of food source quality on the adults of Melolontha melolontha and M. hippocastani

Abstract This paper presents the results of studies on the life span, survival, weight and fecundity of the forest cockchafer (Melolontha hippocastani, Fabricius, 1801) and the common cockchafer (Melolontha melolontha, Linnaeus, 1758) beetle feeding on Alnus glutinosa (L.) Gaertn., Betula pendula Roth., Carpinus betulus L., Fagus sylvatica L., Larix decidua Mill., Prunus serotina (Ehr.) Borkh., Quercus petraea (Matt.) Liebl., Quercus robur L., Robinia pseudoacacia L., Sambucus nigra L. and Sorbus aucuparia L. em. Hedl. The lifespan and weight of beetles as well as female fertility were examined in 2011 and 2013. Specimen for laboratory tests were collected in the field shortly after leaving their overwintering sites in the soil and identical experimental protocols were applied to both examined species. 576 and 432 beetles were tested in 2011 and 2013, respectively. In 2011, beetles were feeding on A. glutinosa, B. pendula, F. sylvatica, L. decidua Q. petraea leaves and on C. betulus, P. serotina, R. pseudoacacia, S. aucuparia and S. nigra in 2013. Both years, beetles feeding on Q. robur leaves were examined as a control. Our results showed that feeding on leaves of Q. robur and Q. petraea had the largest positive impact on the life time, weight and fecundity of the studied beetles. Leaves of F. sylvatica and L. decidua also constituted an adequate food source for the development of M. melolontha. M. hippocastani, however, did not perform as well when feeding on these two tree species. Females of M. melolontha reared on leaves of B. pendula did not lay eggs. The following plant species had a negative impact on the survival and development of the collected specimen and female fertility: A. glutinosa, S. nigra, P. serotina and R. pseudoacacia. Neither beetle species fed on the leaves of A. glutinosa or S. nigra.

Host Plant Use by the Invasive Halyomorpha halys (Stål) on Woody Ornamental Trees and Shrubs.

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive plant-feeding insect native to eastern Asia. This herbivore is highly polyphagous, feeding on and damaging diverse plants, including field crops, vegetables, tree fruits, and ornamentals. Woody ornamental plants provide early- and late-season resources for adults emerging from and returning to overwintering sites, as well as feeding and breeding sites for H. halys throughout the growing season. In this study, we quantify the use of diverse plants by H. halys in two commercial nurseries in Maryland, recording data on the abundance of egg masses, early and late instar nymphs, and adults over a three-year study period. Our specific goals were to provide a quantitative comparison of the use of diverse plant species and cultivated varieties, identify non-hosts that could be used to create landscapes refractory to H. halys, and determine whether the use of plants varied across life stages of H. halys or the taxonomic status of plants. We found broad use of diverse plants in this study, identifying 88 host plants used by all life stages of H. halys. We also highlight the 43 plant taxa that did not support any life stage of H. halys and are thus classified as non-hosts. Interestingly, some of these plants were congeners of highly-used plants, underscoring high intrageneric and intraspecific variation in the use of plants by this polyphagous herbivore. We discuss how the selective planting of non-hosts, especially gymnosperms, may aid in reducing the agricultural and nuisance pest status of this invasive insect.

Conclusion of No Decline in Summer Monarch Population Not Supported

Seven research papers and a cover article recently appeared in the Annals of the Entomological Society of America (online, 5 August 2015) that examined several long-term monarch butterfly monitoring programs. In their cover summary, Davis and Dyer (2015) focused on three studies that concluded there had been no decline over the past two decades in summer breeding numbers for the eastern North American population. This purported lack of decline is at odds with both the observed decline in the size of the population at the Mexican overwintering site (Brower et al. 2012a) and the decline in estimates of monarch egg production during the summer (Pleasants and Oberhauser 2013). To reconcile their conclusion of no summer population decline with the decline observed at the overwintering sites, Davis and Dyer hypothesized that there must be some unknown mortality factor that reduces the population during its fall migration to Mexico. This would ignore the evidence that the key driver of population decline is the massive loss of milkweeds, the larval host plant, in agricultural fields due to the use of glyphosate herbicide in conjunction with the widespread adoption of glyphosate-tolerant corn and soybeans that began in 1996 (Pleasants and Oberhauser 2013). Current conservation efforts in the United States for eastern migratory monarch butterflies are focused on restoration of milkweeds in the summer breeding range. Badgett and Davis (2015) suggested that conservation efforts should be shifted from breeding habitat restoration to focus instead on protecting monarchs during their fall migration. This would be a major change in current conservation efforts, so the support for their contention must be critically examined. Here we address the three papers and show that the purported conclusion of no decline is not supported. Ries et al. used surveys of adult butterflies made during July 19 to August 15 by NABA (North …

Local parasite lineage sharing in temperate grassland birds provides clues about potential origins of Galapagos avian Plasmodium.

Oceanic archipelagos are vulnerable to natural introduction of parasites via migratory birds. Our aim was to characterize the geographic origins of two Plasmodium parasite lineages detected in the Galapagos Islands and in North American breeding bobolinks (Dolichonyx oryzivorus) that regularly stop in Galapagos during migration to their South American overwintering sites. We used samples from a grassland breeding bird assemblage in Nebraska, United States, and parasite DNA sequences from the Galapagos Islands, Ecuador, to compare to global data in a DNA sequence registry. Homologous DNA sequences from parasites detected in bobolinks and more sedentary birds (e.g., brown-headed cowbirds Molothrus ater, and other co-occurring bird species resident on the North American breeding grounds) were compared to those recovered in previous studies from global sites. One parasite lineage that matched between Galapagos birds and the migratory bobolink, Plasmodium lineage B, was the most common lineage detected in the global MalAvi database, matching 49 sequences from unique host/site combinations, 41 of which were of South American origin. We did not detect lineage B in brown-headed cowbirds. The other Galapagos-bobolink match, Plasmodium lineage C, was identical to two other sequences from birds sampled in California. We detected a close variant of lineage C in brown-headed cowbirds. Taken together, this pattern suggests that bobolinks became infected with lineage B on the South American end of their migratory range, and with lineage C on the North American breeding grounds. Overall, we detected more parasite lineages in bobolinks than in cowbirds. Galapagos Plasmodium had similar host breadth compared to the non-Galapagos haemosporidian lineages detected in bobolinks, brown-headed cowbirds, and other grassland species. This study highlights the utility of global haemosporidian data in the context of migratory bird-parasite connectivity. It is possible that migratory bobolinks bring parasites to the Galapagos and that these parasites originate from different biogeographic regions representing both their breeding and overwintering sites.

Overwintering Sites and Winter Mortality of Tetranychus urticae in an Apple Orchard in Korea

The two-spotted spider mite Tetranychus urticae Koch, overwinters in apple culture areas of apple orchards. The mite overwinters in various places on the apple trees, usually in groups of 5-15 females. Overwintering females were mostly found in bark crevices with the hibernation cocoons of the oriental fruit moth, Grapholita molesta Busck. They were also found in small crevices of the bark, and in pedicels left after fruit harvesting. Furthermore, overwintering females were found on rough bark at the bases of buds and spurs, on small limbs and twigs, and in limb crevices and forks. Empty scales of dead diaspidids and coccids, as well as cocoons of lacewings and mummies of parasitized aphids sporadically found on trees, were found to be less common overwintering sites for females of the two-spotted spider mite. In two successive years, the mortality of overwintering females was very high, reaching approximately 72 and 80%. This could be due to the low temperature of winter season in Korea and the low cold tolerance of the mite.

Where does Grapholita molesta (Busck) (Lepidoptera: Tortricidae) overwinter in adjacent peach, pear and apple orchards?

The Oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), is a major pest of tree fruits worldwide, and the diapausing larvae overwinter in cryptic habitats. Investigations of overwintering G. molesta were conducted in adjacent peach, pear and apple orchards in Northern China over three consecutive winters to determine the overwintering site and habitat preferences of the moth. Counts of overwintering larvae in the different orchards demonstrated that the late-maturing peach orchard ('Shenzhou honey peach') was the most preferred overwintering habitat with more than 90% of the collected larvae. Larvae were more abundant in host trees, and they very rarely overwintered in the soil. The overwintering site preferences on the host trees were significantly different; over 50% larvae were located in the tree trunks, and followed by main branches. Most of the G. molesta overwintered on the sunny side of the host trees at or below 60 cm from the ground; a few were cocooned on the shaded sides of the trees or greater than 60 cm from the ground. G. molesta began overwintering between August and October, mid- to late September was the peak period for entering winter diapause during 2011-2013 (77.78, 67.59 and 71.15%, respectively). Our findings improve understanding of the orchard habitat and overwintering site preferences of G. molesta and would be useful in the development of efficient forecasting and pest-management strategies for orchards during the winter and early spring.

Some observations on overwintering sites of adult Culex quinquefasciatus (Diptera: Culicidae) and strategies followed under natural and seminatural conditions.

Field population of adult Culex quinquefasciatus Say, landed in December, congregated and overwintered in indoor artificial sites in Delhi. Repeated sampling strategy by individually collecting the adults was adopted to study their overwintering strategies for 4 years (December to April). They remained vagile and readily repopulated the resting sites after the removal of samples. A large percentage of females was fertile, unfed and nulliparous indicating that reproduction ceased in them. Adult survival was significantly prolonged to a maximum of 3 months under natural conditions. Gonotrophic cycle also got prolonged. Close to quitting, they became gravid and left in April without oviposition. No adults were observed on the sites for the rest of the year. Oviposition was induced in the blood-engorged females when provided with food, water and outdoor conditions. Oviposition might have been induced directly by water and food provided them energy under seminatural conditions. Eggs were laid singly or in the form of rafts, and the number in both the cases was low. Singly laid eggs did not hatch, and in rafts, hatching was ~80 %. Winter conditions seemed to strongly impact fertility, blood feeding, fecundity, oviposition behaviour, egg hatchability and longevity. Use of the overwintering sites as biological tool, as a part of environmental control in IPM, is suggested for organising antivector measures during winter. There is a need of exploring and creating more sites of this kind.

Isolation and characterization of influenza A viruses from environmental water at an overwintering site of migratory birds in Japan

The Izumi plain in Kagoshima prefecture, Japan, is an overwintering site of more than 10,000 cranes. The wet paddy areas are artificially created to provide roosting sites for the cranes every winter. Since wild ducks, known to be a natural reservoir of influenza A viruses, also overwinter in this area, the cranes' roost water likely serves as a source of influenza A virus infection. To assess this potential risk, we collected 126 water samples from the cranes' roost in the 2012/2013 winter season for virus isolation. We isolated six influenza viruses of three subtypes (H3N8, H4N6, and H4N8) from the water samples collected in the months of November and December. Genetic analysis of our isolates indicated that these viruses were genetically similar to the low-pathogenic avian influenza viruses circulating among Eurasian waterfowl. These findings suggest the possibility of the cranes becoming infected with the avian influenza viruses that are present in their roost water.

Karacadağ kışlağı ve Diyarbakır ili hububat alanlarında Süne, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) ergin parazitoit türlerinin Süne erginlerindeki parazitlenme oranları ve dişilerin yumurta verimi

The current was study focused on the adult parasitoids of the Sunn pest, Eurygaster integriceps Puton, which are important factors to suppress the Sunn pest populations. Overwintered Sunn pest adults were collected from Bismil, Ergani, Sur and Central districts of Diyarbakir province of Turkey to determine the difference of fecundity between parasitized and un-parasitized adults. For this purpose, Sunn pest adults were sampled starting from the start of the migration from the overwintering sites to the plains at the end of March and during April, and cereal fields of Diyarbakir province were also surveyed between April and July. Parasitism rates in overwintering Sunn pest female and male were 11.06%-7.83% in 2013-2014, 4.27%-4.01% in 2014 respectively. Comparing the parasitism rates, it was also determined that the adult females of the Sunn pest were preferred over the males. Parasitized females produced significantly less eggs comparing to the un-parasitized ones.

Seasonality and Diapause of Musca autumnalis (Diptera: Muscidae) at its Southern Limits in North America, With Observations on Haematobia irritans (Diptera: Muscidae).

The face fly (Musca autumnalis De Geer) and horn fly (Haematobia irritans ([L.])) were studied at the southern edge of the face fly's North American range, examining southern California geographic distribution, seasonal activity on cattle and in dung, and diapause. Face flies were common only at Pomona (34°03'N, 117°48'W). Other irrigated pastures, even those only slightly inland from Pomona, were probably too warm for face flies, due to a steep west (cooler) to east (warmer) temperature gradient. Horn flies were abundant at all sites. Adult densities on cattle, adults emerging from dung pats, and prevalence of fly-positive pats were assessed for both fly species throughout a year at Pomona. Summer adult horn fly densities of 500-2,000 flies per cow, or face fly densities of 3-10 flies per face, were common. Summer prevalence of face fly-positive pats and horn fly-positive pats was about 20-40% and 30-70%, respectively. Face fly adults diapaused from late October until late March and early April. Horn flies probably diapaused as pupae from late October or early November to early-mid March, although some emerged in winter. Experimental cohorts of October-emerging adult face flies were held in a representative overwintering site. They exhibited hypertrophied fat body and undeveloped oocytes, which are characteristics of diapause, and survived until the following spring. The dominant diapause cues in face and horn flies are probably photoperiod and temperature. Despite warm winter temperatures that would permit activity of both species, and despite relatively long winter day lengths, face flies and most horn flies still diapaused at this latitude.

Trends Observed in Fall Migrant Monarch Butterflies (Lepidoptera: Nymphalidae) East of the Appalachian Mountains at an Inland Stopover in Southern Pennsylvania over an Eighteen Year Period

In total, 11,333 fall migrant monarch butterflies were captured, measured, tagged, and released in southern Pennsylvania over an 18-yr period from 1992 to 2009, excluding 1996 and 2004. Fifty-six (0.494%) were recovered at the Mexican overwintering sites. Hind wing tags had a much higher recovery rate (1.13%) than forewing tags (0.138%). When compared with published recovery rates east of the Appalachians using the same tag type, Pennsylvania was higher than all coastal sites but similar to that of inland Virginia, indicating that inland migrants are more successful. Six U.S. recoveries indicate that monarchs experience considerable eastward wind displacement after leaving the tagging sites. The wild monarchs were divided into three groups for analysis: early (20 Aug–9 Sep), middle (10 Sep–1 Oct), and late (2 Oct–20 Oct) to determine temporal trends. The average forewing length decreased over time, while the percentage of female migrants increased. These trends were not seen in a comparison set of raised monarchs originating from the same general area. As over half the Mexican recoveries came from storm-killed fall 2003 migrants, recoveries were analyzed with and without 2003, and for 2003 alone. More early than middle migrants and no late migrants were recovered. Female migrants were more likely to be recovered from 2003 and overall, but not when 2003 was excluded. The recovery data suggest that males are less likely to make it to Mexico and suffer higher mortality once there during normal overwintering seasons. It also suggests that while early migration is beneficial to both genders, it is even more beneficial for females.

Genetic diversity of highly pathogenic H5N8 avian influenza viruses at a single overwintering site of migratory birds in Japan, 2014/15.

We isolated eight highly pathogenic H5N8 avian influenza viruses (H5N8 HPAIVs) in the 2014/15 winter season at an overwintering site of migratory birds in Japan. Genetic analyses revealed that these isolates were divided into three groups, indicating the co-circulation of three genetic groups of H5N8 HPAIV among these migratory birds. These results also imply the possibility of global redistribution of the H5N8 HPAIVs via the migration of these birds next winter.

Big maggots dig deeper: size-dependent larval dispersal in flies.

The ability of individual animals to select habitats optimal for development and survival can be constrained by the costs of moving through the environment. Animals that seek overwintering sites underground, for example, may be constrained by the energy required to burrow into the soil. We conducted field and laboratory studies to determine the relationship between individual size and overwintering site selection in the tephritid flies, Rhagoletis juglandis and Rhagoletis suavis. We also explored the effect of site selection on pupal mortality, parasitism, and the ability to emerge from overwintering sites after eclosion. In both species, and in both lab and field tests, larger pupae were found at deeper soil depths. In addition, marginally non-significant trends indicated pupae in deeper sites were 48% more likely to survive the overwintering period. Finally, larger individuals were more likely to eclose and emerge from the soil at a given depth, but flies in deep overwintering sites were less likely to emerge from those sites than flies in shallow sites. Our data indicate that overwintering site selection represents a trade-off between avoiding predators and parasites that occur at shallow sites, and the energetic and mortality costs of burrowing to, overwintering in, and emerging from, deeper sites. The size-dependent overwintering site selection demonstrated here has implications for population dynamics and pest control strategies. Some fly control measures, such as the introduction of parasites or predators, will be mitigated when the deepest and least accessible overwintering pupae represent a disproportionately large amount of the population's reproductive capacity.