Birth timing and population changes in greater horseshoe bat colonies (Rhinolophus ferrumequinum) are synchronized by climatic temperature

We counted the births of greater horseshoe bats born at three small breeding colonies in southwest Wales and south-west England at the extreme edge of the species distribution over nine summers (1984–1993). Overall birth timing was almost identical at the three sites (mean of mean birth dates = 13–14 July), but varied widely from year to year. Mean birth timing was synchronized at the three sites in a given year. Early births followed warm springs; a significant negative regression of mean birth date on mean April plus May temperature was evident. A rise of 2^oC accelerated mean birth date by about 18 days. Population levels fell at all three sites following the very late mean birth date of 28 July recorded in 1986, after an extremely cold spring and summer. Recovery of populations in all sites followed a series of warm springs and early mean birth dates, but was hampered by birth sex ratios favouring males for several years. These findings confirm climate, through its effect upon birth timing, and possibly also on sex ratios, as a major factor controlling bat populations, and hence the distribution of bat species.     

Phylogeography of the greater horseshoe bat, Rhinolophus ferrumequinum: contrasting results from mitochondrial and microsatellite data

Phylogeographical studies are typically based on haplotype data, occasionally on nuclear markers such as microsatellites, but rarely combine both. This is unfortunate because the use of markers with contrasting modes of inheritance and rates of evolution might provide a more accurate and comprehensive understanding of a species' history. Here we present a detailed study of the phylogeography of the greater horseshoe bat, Rhinolophus ferrumequinum , using 1098 bp of the mitochondrial ND2 gene from 45 localities from across its Palaearctic range to infer population history. In addition, we re-analysed a large microsatellite data set available for this species and compared the results of both markers to infer population relationships and the historical processes influencing them. We show that mtDNA, the most popular marker in phylogeography studies, yielded a misleading result, and would have led us to conclude erroneously that a single expansion had taken place in Europe. Only by combining the mitochondrial and microsatellite data sets are we able to reconstruct the species' history and show two colonization events in Europe, one before the Last Glacial Maximum (LGM) and one after it. Combining markers also revealed the importance of Asia Minor as an ancient refugium for this species and a source population for the expansion of the greater horseshoe bat into Europe before the LGM.     

Effects of microhabitat,time of day,and weather on predation of gypsy moth larvae

Summary Wire cages with different-sized meshes were placed on trunks and around leaves at different heights in oak trees and in forest litter. Gypsy moth, Lymantria dispar, instars II–V tethered with threads were placed in each cage (instars II–III only in leaf cages) as well as outside the cages. Predation of larvae decreased from near ground to mid-crown in trees and was highest in litter and very low on leaves. Predation in litter was not strongly related to cage type, suggesting that small, invertebrate predators were active there, but IV–V instars on trunks were mainly killed by relatively large predators, probably forest mice and shrews. Influences of the time of day and weather on predation were evaluated by observing tethered V–VI instars in litter and on tree trunks hourly. Ants, particularly carpenter ants (Camponotus ferrugineus) and Formica sp., and probably vertebrates, were conspicuous predators in the litter. Ants were most active at lower relative humidities, while other predators were apparently not influenced by humidity. No daily activity rhythms of predation were noted. Invertebrates appear to be important predators of larvae only in the litter whereas vertebrates, such as forest mice and shrews, also readily attack larvae on tree trunks.     

Microsatellite loci for the greater horseshoe bat,Rhinolophus ferrumequinum (Rhinolophidae,Chiroptera) and their cross‐utility in 17 other bat species

We have isolated 14 polymorphic greater horseshoe bat, Rhinolophus ferrumequinum microsatellite loci. The number of alleles varied from two to 12 in 58 individuals. These loci will be used to assign paternity in order to characterize patterns of breeding and reproductive success in a wild R. ferrumequinum population. Loci were also tested in 17 other bat species. Twelve loci cross‐amplified in other species and three loci were polymorphic in all eight Rhinolophus species tested.     

Studies on the vaginal plug of the Japanese greater horseshoe bat, Rhinolophus ferrumequinum nippon

The vaginal plug of the Japanese greater horseshoe bat is composed of an outer, thick, hard and homogeneous layer originating from the stratum disjunctum of the vaginal mucosa and a thin, soft and opaque central core containing accidentally trapped dead spermatozoa. The vaginal plug appeared to be expelled just before or after ovulation in spring. Immediately after copulation in autumn, uterine spermatozoa were dead but few leucocytes were present. As time passes after copulation, however, the infiltration of leucocytes into the uterus increased gradually, and extensive leucocytic phagocytosis of dead spermatozoa occurred during hibernation.     

Impact of landscape fragmentation on a specialised woodland bat,Rhinolophus hipposideros

For habitat specialists, fragmentation has major consequences as it means less suitable habitat for the species to live in. In a fragmented landscape, we would expect larger, but spatially more clustered, foraging ranges. We studied the impact of landscape fragmentation on the foraging range and habitat exploitation of a specialised forest bat by radiotracking 16 female lesser horseshoe bats Rhinolophus hipposideros in a landscape with connected woodland structures and in a highly fragmented landscape in Carinthia, Austria.Contrary to our expectations, spatial foraging behaviour was not influenced by fragmentation. No differences in the behaviour of the bats between the sites were evident for the foraging ranges (minimum convex polygon, MCP), the core foraging areas (50% kernel), nor the mean or the maximum distances from the roost. However, in the highly fragmented landscape, the foraging activity of individuals was spatially more clustered and the overall MCP of all bats of a colony was greater compared to the less fragmented landscape.Woodland was the most important foraging habitat for the lesser horseshoe bats at both study sites. Habitat selection at the individual MCPs was evident only at the site with low fragmentation. However, in the core foraging areas, woodland was significantly selected over all other habitat types at both study sites.We conclude that (1) conservation measures for colonies of lesser horseshoe bats should be undertaken within 2.5 km of the nursery roost, (2) woodland is the key foraging habitat particularly in the vicinity of the roost, and (3) any loss of woodland near the colonial roosts are likely to negatively influence the colony, since these bats do not seem to be able to adapt their spatial foraging behaviour in a degraded landscape. The inflexible spatial behaviour of this specialised bat highlights the need to compensate for any habitat loss within the foraging range of a bat colony.     

饥饿对大草蛉雄成虫捕食作用的影响

对不同饥饿程度大草蛉雄成虫捕食作用影响的研究表明,饥饿不能改变大草蛉雄成虫捕食作用功能反应类型,饥饿对捕食量影响不显著;大草蛉雄成虫对麦二叉蚜的捕食量（Ｎａ）随着时间（ｔ）的变化,其模型为Ｎａ＝１００／１＋ｅ＾－０．３０８８－０．０９９６ｔ;大草蛉雄成虫在２４ｈ内的捕食速率（Ｖ）与其时间段（ｘ）的关系为Ｖ＝６．７１１７ｘ＾－０．７９２８;大草蛉雄成虫喜好选择捕食麦二叉蚜的低龄若蚜。     

Normal embryonic development of the greater horseshoe bat Rhinolophus ferrumequinum,with special reference to nose leaf formation

The order Chiroptera (bats) is the second largest group of mammals, composed of more than 1,300 species. Although powered flight and echolocation in bats have attracted many biologists, diversity in bat facial morphology has been almost neglected. Some bat species have a “nose leaf,” a leaf-like epithelial appendage around their nostrils. The nose leaf appears to have been acquired at least three times independently in bat evolution, and its morphology is highly diverse among bats species. Internal tissue morphology of nose-leaves has been investigated through histological analyses of late-stage fetuses of some bat species possessing the nose leaf. However, the proximate factors that bring about chiropteran nose-leaves have not been identified. As an initial step to address the question above, we describe the normal embryonic development of the greater horseshoe bat Rhinolophus ferrumequinum, and examine development of the tissues associated with their nose leaf during embryogenesis through histological analyses. We found that the nose leaf of R. ferrumequinum is formed through two phases. First, the primordium of the nose leaf appears as two tissue bulges aligned top and bottom on the face at embryonic stages 15–16. Second, the sub-regions of the nose leaf are differentiated through ingrowth as well as outgrowth of the epithelium at stage 17. In embryogenesis of Carollia perspicillata, a phyllostomid species with a nose leaf, the nose leaf primordium is formed as a small tissue bulge on the nostril at stage 17. This tissue bulge grows into a dorsally projected thin epithelial structure. Such differences in the nose leaf developmental process between chiropteran lineages may suggest that distinct developmental mechanisms have been employed in each lineage's nose leaf evolution.     

To females of a noctuid moth,male courtship songs are nothing more than bat echolocation calls

It has been proposed that intraspecific ultrasonic communication observed in some moths evolved, through sexual selection, subsequent to the development of ears sensitive to echolocation calls of insectivorous bats. Given this scenario, the receiver bias model of signal evolution argues that acoustic communication in moths should have evolved through the exploitation of receivers'' sensory bias towards bat ultrasound. We tested this model using a noctuid moth Spodoptera litura, males of which were recently found to produce courtship ultrasound. We first investigated the mechanism of sound production in the male moth, and subsequently the role of the sound with reference to the female''s ability to discriminate male courtship songs from bat calls. We found that males have sex-specific tymbals for ultrasound emission, and that the broadcast of either male songs or simulated bat calls equally increased the acceptance of muted males by the female. It was concluded that females of this moth do not distinguish between male songs and bat calls, supporting the idea that acoustic communication in this moth evolved through a sensory exploitation process.     

Impact of predation by spiders on a territorial damselfly (Odonata: Calopterygidae)

Summary Predation by orb-weaving spiders and crab spiders on the damselfly Calopteryx haemorrhoidalis was studied at a small stream in Southern France. One species of orb-weaving spider, Larinioides folium, caught 76% of the damselflies which fell prey to spiders. Displacement experiments on spiders on sections of bank and the positioning of webs in male territories show that the density and distribution of damselflies is not influenced by orbweb density or by the position of webs. Predation rates corresponded to orb-web density, but neither for sex nor for stage was there a relationship with damselfly density. Mean daily predation rates ranged between 0.9% for females and 4.1% for adult males. Predation risk to adult damselflies by orb-weaving spiders was male biased, whereas among tenerals there was no bias. Males were captured more frequently at territories near the water. Captures show a maximum at noon when territorial disputes of adult males were most frequent. After orbwebs were placed within territories predation rate of males was strongly increased. Predation risk to adult females in the direct vicinity of the stream was less than in the bank vegetation where they perch close to orbwebs. The risk of predation by crab spiders, which catch damselflies at their perching sites, was not sex-biased.     

The impact of predation on the viburnum whitefly, (Aleurotrachelus jelinekii)

Summary In association with a detailed study of the population dynamics of the viburnum whitefly, Aleurotrachelus jelinekii, observations were made on the predators including spiders and five species of insect, notably the mirid Campyloneura virgula and the neuropteran Conwentzia psociformis. Although the species richness of the predator guild was positively correlated with prey population density, at the individual level there was little evidence over twelve years of a density dependent relationship. In these populations natural enemies do not seem to play an important role in the dynamics.     

Shoaling behaviour in a surface-dwelling and a cave-dwelling population of a barb <Emphasis Type="Italic">Garra barreimiae</Emphasis> (Cyprinidae,Teleostei)

We studied shoaling behaviour in a species of fish (Garra barreimiae) from Oman. We compared two populations (a surface-dwelling and a cave-dwelling population) with different theoretical costs and benefits of shoaling. We measured the tendency to associate with a shoal of conspecifics. The stimulus shoal was confined to (1) clear Plexiglas cylinders in light, (2) wire-mesh cylinders in light, or (3) wire-mesh cylinders in darkness. The surface form exhibited a strong preference for the stimulus shoal during the experiments in light, but also in darkness, when only non-visual cues from the shoal could be perceived. The cave form did not show a preference when solely visual cues were available (Plexiglas cylinder). When non-visual cues from the shoal could be perceived (wire-mesh), the cave form did show a preference to associate with the shoal, but the shoaling tendency was considerably weaker than in the surface form. The shoaling tendency has probably been genetically reduced in the cave form.     

Effects of predation on clutch size and egg dispersion in the codling moth Laspeyresia pomonella

ABSTRACT.

• 1 The effects of predation on clutch size and egg dispersion in the codling moth Laspeyresia pomonella (L.) were experimentally studied in an orchard by recording survival of eggs glued onto different substrates.
• 2 Egg mortality due to sucking insects was readily distinguishable from that due to chewing insects.
• 3 In both the field and laboratory, females preferred to deposit eggs singly on the uppersides of leaves.
• 4 Eggs on the uppersides of leaves and on fruit survived significantly better than did those on the undersides of leaves or on twigs.
• 5 Egg losses were highest during the early part of the flight season.
• 6 The smallest (one egg) and largest (nine eggs) clutches, associated with one egg-bearing leaf per twig, both suffered the lowest rates of predation. Factors selecting against oviposition on fruits and production of large clutch sizes are presented and discussed.

     

苹果蠹蛾种群遗传多样性研究进展

苹果蠹蛾是重要的世界性果树害虫,寄主广泛,通过形成各种生态型或种群适应新入侵环境,对当地果品生产造成严重损失。本文综述了国内外有关苹果蠹蛾遗传多样性的研究进展。相关研究表明,寄主植物、地理隔离和杀虫剂等因素影响种群间的遗传多样性和遗传分化。其中,地理隔离是种群间形成遗传分化的主要原因之一,寄主分布格局、气候条件、虫体飞行能力和人为活动等因素都会影响种群间遗传分化的程度。苹果蠹蛾是我国重要的入侵害虫,我国东北地区和西北地区的苹果蠹蛾种群具有不同的遗传多样性水平,并且种群间有一定程度的分化,今后需要进一步研究影响我国苹果蠹蛾种群遗传的重要因素,明确该虫种群间分化情况、入侵来源和扩散路径,这对于延缓苹果蠹蛾在我国的扩散,制定合理有效的综合防治策略具有重要意义。     

Discrimination and production of disparlure enantiomers by the gypsy moth and the nun moth

ABSTRACT. Two odour receptor cells were physiologically identified within male antennal hair sensillae of the gypsy moth, Lymantria dispar L, and the nun moth, L. monacha L. In the gypsy moth, one cell responded to (+)-disparlure, while a neighbouring cell responded to (-)-disparlure. In the nun moth both cells responded to (+)-disparlure. The lack of sensitivity to (-)-disparlure in the nun moth was corroborated by electroantennogram (EAG) recordings, which indicated no affinity to this enantiomer. Single cell responses of male gypsy moth to different concentrations of the synthetic enantiomers of disparlure were then compared to responses elicited by hexane extracts of female glands of both species. The gypsy moth's extracts stimulated almost exclusively the receptor cell specialized for (+)-disparlure, while both cells were simultaneously stimulated by the extracts of the nun moths. From the response characteristic of the cells it is estimated that pheromone production of the nun moth is about 10% (+) and 90% (-)-disparlure, and that of the gypsy moth is almost 100% (+)-disparlure. Stimulation of the antenna of each species by female gland extracts of both species did not indicate the presence of receptors for other hexane elutable pheromone components in either species.     

Quantitative studies on the pathogenicity of Nosema carpocapsae,a microsporidian pathogen of the codling moth,Cydia pomonella,in New Zealand

The pathogenicity of Nosema carpocapsae for codling moth was studied using dose-infectivity experiments. The IC₅₀ (median infective concentration) was similar for the five larval instars (range 4.0 × 10³ to 6.7 × 10⁴ spores/ml). Spore loads in moths ranged from 6.0 × 10⁶ to 7.1 × 10⁷ spores per moth and varied with dose and with larval age at infection. The infection does not cause mortality but does reduce the fecundity and fertility of infected moths. Nosema carpocapsae is transmitted transovarially as well as horizontally. Infected eggs were not produced by healthy females mated with infected males, although such pairs generally produced fewer eggs than healthy pairs.