Flexible pollination system in an unpalatable shrub Daphne miyabeana (Thymelaeaceae)

The stability of plant reproductive success is dependent on the reproductive system of the plant and the surrounding pollinator assemblages. Here we documented the pollination ecology of a shrub, Daphne miyabeana (Thymelaeaceae), that is unpalatable to deer in two different habitats (open and closed canopy) at a site with severe deer browsing. We found that 31.22 ± 3.07% (mean ± SE) and 9.01 ± 1.71% of the total number of D. miyabeana flowers become fruits in open and closed habitats, respectively. Although spontaneous selfing was possible, the fruit set of that was much lower than the fruit set of an artificial outcrossing treatment. In the closed habitat, the fruit set of the natural pollination was lower than that of artificial outcrossing, whereas in the open habitat the fruit set of those two were similar. In the open habitat, small bees were the major flower visitors, whereas in the closed habitat, ants were the major flower visitors, which did not contribute to pollination. Our findings suggest that D. miyabeana is pollinated by occasional visits of small bees, but it is also self‐compatible and spontaneous selfing is possible. Although its pollination is shaped by abiotic environmental factors, D. miyabeana can reproduce in different habitat conditions. These flexible reproductive systems may be an advantage in coping with the recent environmental change in forest habitats.     

Sexual interference within flowers of Chamerion angustifolium

Hermaphroditism is prevalent in plants but may allow interference between male function (pollen removal and dispersal) and female function (pollen receipt and seed production) within a flower. Temporal or spatial segregation of gender within a hermaphroditic flower may evolve to reduce this interference and enhance male and female reproductive success. We tested this hypothesis using Chamerion angustifolium (Onagraceae), in which pollen removal (male) and pollen deposition (female) were measured directly on hermaphroditic and experimentally produced unisexual flowers. During a single flower visit in the field, bees deposited 159±24 (SE) pollen grains on a stigma and removed 1058±198 grains from each flower. Anther removal did not alter deposition rates. In the laboratory, bees removed 2669±273 pollen grains and deposited 209±72.3 cross-pollen and 120±28.4 facilitated self-pollen grains per visit. The presence of anthers significantly reduced cross-pollen deposition on the stigma. In contrast, pollen removal was not affected by presence of the pistil. These results suggest that within-flower interference affects female function and represents a fitness cost that can be reduced through temporal segregation of gender within the flower. Co-ordinating editor: S.-M. Chang     

A resource-based conservation approach for an endangered ecotone species: the Ilex Hairstreak (Satyrium ilicis) in Flanders (north Belgium)

Ecotones are often species-rich and harbour specific resources and environmental conditions for invertebrates. Despite their functional significance for conservation, they are often not explicitly included in biotope typologies relevant to conservation policy and management (e.g., the European Habitats Directive). The Ilex Hairstreak (Satyrium ilicis) is a species of European conservation concern and a typical ecotone species inhabiting gradients from open (e.g., heathland, grassland) to closed vegetation (e.g., woodland). Here, we investigated its occurrence and habitat use at different spatial scales in Flanders (north Belgium). At a regional scale, species distribution modelling predicted 1,152 grid cells of 1 × 1 km² to be suitable of which 190 were presumed to occur within colonization capacity (±2.5 km). At a local scale, adult butterflies were more abundant on sites sheltered by bushes and small trees and with nectar sources in the vicinity of tall oak trees (mate locating sites). For egg-laying, females preferred oaks of intermediate height (50–150 cm) with many low branches at some distance from the nearest woodland edge (12 m). Additionally, Alder Buckthorn (Frangula alnus) was abundant as well as a herb layer of 10–15 cm. 73 % of the eggs were parasitized and parasitism occurred more often within sites where small oaks were very abundant. Making use of our results, we suggest conservation measures at different scales for this endangered ecotone species: policy measures at a regional level to delineate functional conservation units and local management measures using a resource-based approach.     

Aerial dispersal ability does not drive spider success in a crop landscape

1. Although spiders can colonise ecosystems by air, dispersal capabilities differ among spider species. Web‐building spiders are thought to balloon at higher rates than hunting spiders. Spider success in agricultural systems may also depend on habitat preferences. Few studies have examined the success of aerially dispersing spiders in crop systems, and information about the dispersal capabilities of spiders in putative source habitats is limited. 2. Spiders were monitored in the air and on the foliage of vineyards and adjacent oak woodland in order to compare the aerial spider faunas between these disparate habitats and to determine whether highly dispersive species contributed disproportionately to the spider community in vineyards. 3. The results show that most aerially dispersing spiders in both habitats were web‐building dwarf spiders, Erigone spp. (Linyphiidae), although hunting spiders were also well represented in the air, especially in oak woodland. Most woodland spiders in the air appeared to be residents of oak woodland and probably dispersed only short distances. 4. Conversely, only a subset of the aerial spider fauna established in vineyards in high numbers. Spiders that dominated the aerial fauna were under‐represented on vineyard foliage, whereas several hunting spiders dispersed aerially at low rates but dominated vineyard spider composition. 5. These results suggest that aerial dispersal ability may allow spiders to reach crop systems, but that establishment depends on habitat preferences and/or competitive ability.     

Seasonal activity patterns of Ixodes pacificus nymphs in relation to climatic conditions

Abstract In western North America, the tick Ixodes pacificus Cooley & Kohls (Acari: Ixodidae) is the primary vector to humans and domestic animals of the disease agents causing Lyme disease and granulocytic ehrlichiosis. We examined the seasonal activity patterns of I. pacificus nymphs over a 4‐year period, including the wet and cold El Niño winter/spring of 1998, in a dry oak/madrone woodland, and for one year in a cooler and moister redwood/tanoak woodland in Mendocino County, California. Linear regressions were used to estimate when nymphal densities first exceeded and then fell below 25, 50 and 75% of the recorded yearly peak densities. In oak/madrone woodland, nymphs typically were active by mid‐March, reached 50% of their yearly peak densities in early to mid‐April, peaked by early May, fell below 50% of their peak densities by early to mid‐June, and were absent by late July to mid‐August. The lengths of the periods with nymphal densities exceeding 50 and 75% of the recorded yearly peaks in oak/madrone woodland were associated positively with rainfall and negatively with maximum air temperatures during April–May. Moreover, nymphal numbers typically reached 50% of their peak 10–15 days later, remained at levels above 50% of the peak 1.3–1.5 times longer, and started declining 4–6 weeks later under cooler, moister climatic conditions (oak/madrone woodland in 1998 and redwood/tanoak woodland in 2000) relative to warmer, drier conditions (oak/madrone woodland in 2000–2001). In oak/madrone woodland, nymphal densities typically started to decline when mean maximum daily air temperatures exceeded 23°C. Nymphal densities were higher in dry oak/madrone relative to moist redwood/tanoak woodland from mid‐March to late May 2000, similar in both habitat types in early June, but higher in redwood/tanoak woodland from late June onwards. We conclude that large‐scale studies of the density of I. pacificus nymphs in California need to consider spatial variation in the length of nymphal activity periods and select temporal sampling regimens that yield representative data for all included habitat types.     

Emergence and mating behavior of the oriental fruit moth Cydia molesta (Lepidoptera: Tortricidae) and its potential for reproduction

The Oriental fruit moth, Cydia molesta (Busck, 1916) (Lepidoptera: Tortricidae), is a key pest of fruit and is widely distributed around the world. There are important connections between its behavior and biology and its management in agriculture, but few studies have investigated the associations between adult behaviors and oviposition. In this study, adult emergence, mating, and reproduction were investigated under laboratory and field conditions. The ratio of females to males at eclosion was approximately 1:1. When one virgin female had access to one virgin male, 66% and 34% of the couples copulated just once and twice, respectively; and the infertility rate of eggs (21.39 ± 1.25%) did not vary daily. Males, given access to one new female daily, could copulate multiple times, whereas females seldom mated more than once, indicating a male-biased operational sex ratio, but mating status of the male parent had no effect on progeny egg reproduction. Also, the number of eggs that hatched by all female partners of a male was inversely proportional to copulation duration for the female laying the eggs for total female reproductive success; and the number of eggs laid by all female partners of a male was proportional to their number of matings for total male reproductive success. However, the total number of eggs that hatched did not significantly differ for eggs laid by a female given new virgin males daily for mating (17.75 ± 4.28) versus eggs laid by virgin females (19.17 ± 7.51) presented daily with a male that re-mated daily with the series of females. Therefore, our results showed that females engaged in mate choice and males engaged in mate competition, affecting egg production, a factor that may be used to enhance mating disruption technology against Cydia molesta.     

Fecundity and reproductive output of the caridean shrimp Periclimenes paivai associated with scyphozoan jellyfish

Periclimenes paivai is notable for its symbiotic lifestyle with jellyfish. The objective of this study was to investigate the fecundity and reproductive output of females, and specifically to determine whether females protected in their host have a greater reproductive success than other shrimp species. All anatomical parts of the medusae were analyzed and the P. paivai individuals were separated. Among 83 females analyzed, 65 presented embryos in the first developmental stage, and 18 were in the final stage of development. The mean fecundity was 229.08 ± 120.04 in initial-stage embryos and 191 ± 114.76 in final-stage embryos. We observed a positive relationship between the embryo number and the female size; however, the embryo number was not related to the embryonic stage, which indicates that females did not lose their embryos during the incubation period. The weight of brood mass during production is closely related to the female weight according to the results of linear regression, as fecundity increased with female size. In its symbiosis, P. paivai can increase the amount of energy used to produce embryos (mean reproductive output = 10.38%) and can elevate the reproductive success.     

Reproductive biology of Pachira aquatica Aubl. (Malvaceae: Bombacoideae): a tropical tree pollinated by bats,sphingid moths and honey bees

We investigated the reproductive biology, including the floral biology, pollination biology, breeding system and reproductive success, of Pachira aquatica, a native and dominant tropical tree of fresh water wetlands, throughout the coastal plain of the Gulf of Mexico. The flowers present nocturnal anthesis, copious nectar production and sugar concentration (range 18–23%) suitable for nocturnal visitors such as bats and sphingid moths. The main nocturnal visitors were bats and sphingid moths while bees were the main diurnal visitors. There were no differences in legitimate visitation rates among bats, moths and honey bees. Bats and honey bees fed mainly on pollen while moths fed on nectar, suggesting resource partitioning. Eight species of bats carried pollen but Leptonycteris yerbabuenae is probably the most effective pollinator due to its higher pollen loads. The sphingid moths Manduca rustica, Cocytius duponchel and Eumorpha satellitia were recorded visiting flowers. Hand pollination experiments indicated a predominant outcrossing breeding system. Open pollination experiments resulted in a null fruit set, indicating pollen limitation; however, mean reproductive success, according to a seasonal census, was 17 ± 3%; these contrasting results could be explained by the seasonal availability of pollinators. We conclude that P. aquatica is an outcrossing species with a pollination system originally specialized for bats and sphingid moths, which could be driven to a multimodal pollination system due to the introduction of honey bees to tropical America.     

The breeding biology of Rose-ringed Parakeets Psittacula krameri in England during a period of rapid population expansion

Capsule The reproductive rate of Rose-ringed Parakeets in the UK was higher in 2001-2003 than previously estimated.

Aim To measure reproductive rate and the factors affecting this in Rose-ringed Parakeets in England during a period of rapid expansion in population of this potential invasive species.

Methods During 2001–2003, 108 nests were located and monitored in southwest London, southeast London and the Isle of Thanet. Nest survival using the Mayfield method, fledging success and the characteristics of the nest and surrounding vegetation were measured.

Results The mean date of first egg was 26 March?±?1.3 days and the median clutch size was 4 eggs. Mayfield nest survival rate was 72%. Reproductive success was 1.4?±?0.3 young fledged per nest. Parakeets bred predominantly in ash (Fraxinus) and oak (Quercus). Nest trees had a diameter at breast height (DBH) of 73.7?±?4.7?cm (mean?±?se).

Conclusion Reproductive success in this parakeet was higher than previously estimated (0.8 young fledged per nest prior to 1999). This reproductive output is sufficient to explain the rapid increase in Rose-ringed Parakeet numbers (from an estimated 1500 birds in 1996 to nearly 10,000 birds by 2004) if Rose-ringed Parakeets have a low death rate similar to other parrots.     

The effect of woodland area on avian community composition in a fragmented southern UK landscape and associated management recommendations

ABSTRACT

Capsule: Smaller woodlands not only support fewer species but also show different avian community composition due to loss of woodland interior and an increase in edge habitat.

Aims: To use observed community composition changes, rather than traditional total species richness-area relationships, to make area-specific management recommendations for optimizing woodland habitat for avian communities in fragmented landscapes.

Methods: 17 woodlands were selected in Oxfordshire, UK, with areas between 0.2 and 120 ha. Three dawn area searches were conducted in each woodland between 1st April and 28th May 2016 to record encounter rates for each species. The impact of internal habitat variation on woodland comparability was assessed using habitat surveys.

Results: Woodlands with area less than 3.6 ha showed a significant positive relationship between total avian species richness and woodland area. Woodlands with area over 3.6 ha were all consistent with a mean (± se) total richness of 25.4?±?0.6 species, however the number of woodland specialists continued to increase with woodland area. Woodland generalists dominated the total encounter rate across the area range, however the fractional contribution of woodland specialists showed a significant positive correlation with woodland area, while the fractional contribution of non-woodland species significantly decreased. Non-woodland species numbers peaked in mid-sized woodlands with enhanced habitat heterogeneity.

Conclusions: Community composition analysis enabled more targeted recommendations than total species richness analysis, specifically: large woodlands (over 25?ha) in southern UK should focus conservation efforts on providing the specific internal habitats required by woodland specialists; medium-sized woodlands (between approximately 4 and 25?ha) should focus on promoting internal habitat variety, which can benefit both woodland species and non-woodland species of conservation concern in the surrounding landscape; small woodlands (under 4?ha) should focus on providing nesting opportunities for non-woodland species and on improving connectivity to maximize habitat for woodland generalists and facilitate movement of woodland specialists.     

A multi‐data ensemble approach for predicting woodland type distribution: Oak woodland in Britain

Interactions between soil, topography, and climatic site factors can exacerbate and/or alleviate the vulnerability of oak woodland to climate change. Reducing climate‐related impacts on oak woodland habitats and ecosystems through adaptation management requires knowledge of different site interactions in relation to species tolerance. In Britain, the required thematic detail of woodland type is unavailable from digital maps. A species distribution model (SDM) ensemble, using biomod2 algorithms, was used to predict oak woodland. The model was cross‐validated (50%:50% ‐ training:testing) 30 times, with each of 15 random sets of absence data, matching the size of presence data, to maximize environmental variation while maintaining data prevalence. Four biomod2 algorithms provided stable and consistent TSS‐weighted ensemble mean results predicting oak woodland as a probability raster. Biophysical data from the Ecological Site Classification (forest site classification) for Britain were used to characterize oak woodland sites. Several forest datasets were used, each with merits and weaknesses: public forest estate subcompartment database map (PFE map) for oak‐stand locations as a training dataset; the national forest inventory (NFI) “published regional reports” of oak woodland area; and an “NFI map” of indicative forest type broad habitat. Broadleaved woodland polygons of the NFI map were filled with the biomod2 oak woodland probability raster. Ranked pixels were selected up to the published NFI regional area estimate of oak woodland and matched to the elevation distribution of oak woodland stands, from “NFI survey” sample squares. Validation using separate oak woodland data showed that the elevation filter significantly improved the accuracy of predictions from 55% (p = .53) to 83% coincidence success rate (p < .0001). The biomod2 ensemble, with masking and filtering, produced a predicted oak woodland map, from which site characteristics will be used in climate change interaction studies, supporting adaptation management recommendations for forest policy and practice.     

Scale-sensitive landscape complementation determines habitat suitability for a territorial generalist

Evaluating habitat suitability is often complex, as habitat effects may be scale‐dependent, critical resources may be spatially segregated, and resource availability may also depend on intra‐ and inter‐specific interactions. Using analyses that spanned multiple years and spatial scales, we investigated habitat requirements of a territorial generalist, the common raven Corvus corax, in a relatively pristine woodland, Bia?owie?a Forest (E Poland). We compiled data from multiple raven surveys conducted between 1985 and 2001. Ravens were regularly distributed over the entire study area but declined in density over 50% within the 16 yr interval. In the same period game and forest management significantly reduced ungulate densities and likely diminished the habitat quality with regard to food supply, especially carrion. To better understand habitat requirements of ravens we studied breeding performance in relation to three different habitat types across multiple scales: open areas, coniferous‐dominated forest, and deciduous‐dominated forest. We found a prominent dissimilarity between raven nesting and foraging habitats highlighting the importance of resource complementation for ravens. On a fine scale, large old pines were exclusively selected as nesting trees and nesting areas were generally coniferous‐dominated. However, at increasingly broader scales, coniferous habitats were negatively associated with raven reproductive success as those habitats likely provide a lower food supply. Only where the coniferous nesting areas at smaller scales were complemented with high percentages of deciduous forests and open areas at broader scales did the breeding performance increase. In addition to habitat composition, intra‐specific interactions were important determinants of reproductive performance and very successful neighbors decreased reproductive performance of a focal pair. Most of previous studies have investigated resource complementation in terms of habitat edges or proximity of complementing resource patches. Our study demonstrates that the concept of landscape complementation also applies to gradients in landscape composition and emphasizes the importance of scales and intraspecific interactions in habitat analyses.     

Bumble bee colony growth and reproduction on reclaimed surface coal mines

Reclamation of coal mine lands in the eastern United States creates pockets of grassland habitat in an otherwise predominantly forested region. These sites may represent an opportunity for pollinator conservation if they provide valuable foraging habitat for wild bees. To determine site characteristics that influence bee success on reclamation lands, we monitored growth and reproduction of 24 commercially reared bumble bee (Bombus impatiens) colonies placed on 12 former coal mines (aged 2 to 30+ years post‐reclamation) in Ohio, U.S.A. Twenty colonies survived the duration of the experiment (May–August 2014). All colonies produced both new queens (mean 21.0 ± 37.0 SD) and males (36.5 ± 36.5), in proportion to overall colony size. Results of generalized linear models indicate that colony growth and reproduction increased with floral diversity and species turnover, and declined with site area and the proportion of forest in the surrounding landscape. The sex ratio of reproductive offspring was significantly more male‐biased on sites with low flower diversity, underscoring the importance of floral diversity for meeting the higher resource demands of queen production. Floral resource composition and consistency were influenced by site age and surrounding landscape. Older sites had higher floral diversity and species turnover throughout the season than younger sites, and included high‐quality native bee forage plants. We discuss the implications of this study for reclamation project managers seeking to promote bee reproduction and conservation.     

Remains of Holocene giant pandas from Jiangdong Mountain (Yunnan,China) and their relevance to the evolution of quaternary environments in south-western China

Two subfossil partial skeletons of male giant pandas (Ailuropoda melanoleuca) were recovered, along with remains of 16 other mammalian species, from a natural sinkhole on Jiangdong Mountain (south-western Yunnan, China). The panda and other mammalian bones from the sinkhole's upper chamber yielded tightly clustered accelerator mass spectrometry corrected radiocarbon ages of 8470–8250 yr BP, and the panda remains from the lower chamber were found to be 5025 ± 35 yr BP. The bones represent a natural accumulation of mostly large mammals (>30 kg), which had fallen accidentally into the sinkhole. The Jiangdong Mountain mammal assemblage comprises mostly obligate forest-dwellers such as the giant panda, Asian elephant and Sumatran rhinoceros, but the presence of the horse and gaur suggests a more open woodland habitat. Giant pandas were distributed widely in southern China during the Pleistocene, but are now restricted to dense stands of bamboo within temperate forests surrounding the Sichuan Basin. The evidence from Jiangdong Mountain indicates that suitable habitat for pandas extended west of the Salween River through the mid-Holocene. Rapid deforestation of the area in historical times is suggested by an accumulation of cave fill below the opening of the sinkhole containing pieces of an early to middle Ming Dynasty bowl.     

Floral biology and reproductive isolation by floral scent in three sympatric aroid species in French Guiana

We studied the reproductive biology of three sympatric Araceae species, Anthurium sagittatum, A. thrinax and Spathiphyllum humboldtii in French Guiana. The plants flowered simultaneously and were visited by scent‐collecting male euglossine bees, which were apparently their major pollinators. In total, each species was visited by 3–7 euglossine species, and 2–3 euglossine species accounted for at least 80% of all flower visits, with visits being plant species‐specific. Floral scent consisted of 6–10 main compounds, which made up 76–94% of the total amount of volatiles and were specific in these high amounts to each plant species. We suggest that the different floral scents lead to clear separation of the main pollinating euglossine species, providing a directed and efficient intraspecific pollen flow that results in high reproductive success. Since the simple floral (inflorescence) morphology of the studied plants does not support any morphological mechanisms to exclude visitors, as for example in euglossine‐pollinated perfume orchids, floral scent might be of major importance for the reproductive isolation and sympatric occurrence of these plants.     

The influence of tree species and edge effects on pheromone trap catches of oak processionary moth Thaumetopoea processionea (L.) in the U.K.

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Home Range,Body Condition,and Survival of Rehabilitated Raccoons (Procyon lotor) During Their First Winter

The effects of raccoon (Procyon lotor) rehabilitation on postrelease survivorship are unknown. Raccoon rehabilitation success was measured as differences in prewinter body condition, home range size, distance to manmade structures, and during-winter survival between raccoons in the wild and those who have been rehabilitated. Prewinter body condition did not differ between wild and rehabilitated raccoons, but there was a trend for rehabilitated raccoons to have better body conditions. There was no difference between wild and rehabilitated raccoon adaptive kernel (AK) home range for 95% and 90% AK home ranges, or for core (50% AK) use areas. There was no sex difference in distance traveled from the release site within rehabilitated raccoons. However, rehabilitated raccoons were found significantly closer (49.4 ± 4.7 m) to manmade structures than wild raccoons (92.2 ± 14.4 m), and female raccoons were found significantly closer (64.8 ± 4.5 m) to manmade structures than male raccoons (72.3 ± 17.6 m). The results of this study indicate that raccoons can be successfully rehabilitated, but they may occupy habitat closer to manmade structures than wild raccoons.     

MECHANISM OF SELECTION FAVORING A WIDE TUBULAR COROLLA IN CAMPANULA PUNCTATA

A previous study of Campanula punctata pollinated by Bombus diversus showed greater male reproductive success in plants with wider corollas when male reproductive success was measured by paternity analysis. Pollen removal alone was not a good measure of male reproductive success. The aim of the current study is to elucidate the mechanism underlying the selection on corolla width in C. punctata. Multiple regression analysis of male reproductive success in experimental populations revealed that the advantage of a wide corolla to the male is independent of the corolla width of pollen recipients, indicating that the position of pollen deposited on Bombus may not be an important factor for selection. However, the number of pollen grains that fell on the petal or off the flower and were lost at the first visit of Bombus (pollen fall) decreased with increasing corolla width, so that most pollen grains removed from a wide flower were deposited onto the pollinator. In a narrow flower, a greater proportion of the pollen removed was wasted through pollen fall. Pollen removal does not reflect male reproductive success, at least in part because of the loss of pollen in some flowers through pollen fall. The positive relationship between wider corollas and reduced loss of pollen through pollen fall is likely to lead to greater male reproductive success of wider flowers under repeated visits of pollinators. Decreased pollen fall, probably due to more gentle contact between pollen and bees in flowers with wider corollas, may be one of the mechanisms underlying the selection on corolla width of C. punctata.     

Breeding biology of the endangered Dupont’s Lark Chersophilus duponti in two separate Spanish shrub-steppes

Capsule: The Dupont’s Lark Chersophilus duponti in Iberia has relatively high breeding success in both core and fragmented habitats, so population declines are more likely to be the result of low juvenile or adult survival.

Aims: To measure important aspects of the reproductive biology of one of the most endangered and least known larks: the Dupont’s Lark C. duponti.

Methods: We monitored 36 nests in 2 Spanish shrub-steppes, one holding one of the largest European populations (250 pairs) and one composed by fragmented habitat patches holding a smaller population (50 pairs).

Results: The breeding season went from late-March to early July. Overall mean (±sd) clutch size was 3.47?±?0.56, and the number of fledglings per successful nest was 3.0?±?1.15. Mean nestling period was short (8.2 days). Nests showed similar daily survival rate during the incubation period (0.9750?±?0.0110) as during the nestling period (0.9545?±?0.0168), with a mean breeding success of 50%. Predation was the main cause of complete nest failure (83.3% of failed nests in both localities).

Conclusion: Breeding parameters did show no significant variation between populations. Breeding success in both sites was generally higher than recorded in previous studies of this and most other lark species, which suggests that breeding success does not compromise long-term viability of these populations. The decline of the studied populations should be explained by other causes, such as a general decrease in habitat quality, habitat loss or habitat fragmentation.