bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between phytophagous insects and their Opuntia hosts
Authors: MORAN V. C. 
Published: March 2008

Abstract.

The cactophagous insect community on opuntias is analysed to show the number of insect species in different taxa. An extension of this analysis gives the average species complement on large and small opuntias.
A highly significant positive correlation is found between the total number of phytophagous insect species on individual Opuntia species and a measure of the overall ‘architecture’ of their host plants.
The specificity of the phytophagous insects on opuntias is briefly considered and the community as a whole analysed by guilds. The co‐evolution of the Opuntia‐feeding insects and their hosts has culminated in a community of specialist insects to the exclusion of nearly all generalist phytophages.
The life history strategies of the Opuntia‐feeding insects are reviewed. Common to all developmental stages are morphological and behavioural adaptations that reduce the risk of attack by natural enemies. This is clearly the consequence of living on structurally simple host plants where there is little place to hide.
The possible influence of insect herbivores on Opuntia evolution is discussed.
An understanding of the interactions between the phytophagous insect community and opuntias has clear implications for the biological control of alien Opuntia weeds.
Colour polymorphism in nymphs of the genus Eupteryx (Hemiptera: Cicadellidae)
Authors: STILING PETER D. 
Published: March 2008

Abstract.

The colour morphs of fourth and fifth instar nymphs of E. cyclops and E. urticae are described and their geographic distributions in southeast Wales are examined.
Morph frequencies are influenced by Chalarus parasites (Diptera: Pipunculidae).
Ant species distribution in a sandy coastal plain
Authors: BOOMSMA J. J. , DE VRIES A. 
Published: March 2008

Abstract.

Three species of ants, Lasius niger, Myrmica rubra and Myrmica scabrinodis, have been recorded in a 20‐year‐old coastal plain on the Dutch Wadden Zee island, Schiermonnikoog.
The habitats of these species appeared to be clearly segregated, both horizontally (different parts of the plain) and vertically (along dune slope gradients in the plain).
Lasius niger is distributed throughout the plain in sparsely vegetated sand‐dunes and in mounds covered with turf of Festuca rubra ssp. litoralis, but always in areas that are only waterlogged or inundated in winter.
Myrmica rubra is limited to Festuca‐turf, occurring in a distinct zone along the bases of small dunes and on isolated mounds.
Myrmica scabrinodis only occurs in mounds covered with Festuca‐tutf and rarely in the small dunes.
Analysis of soil, vegetation, inundation and salinity of the ground‐water demonstrated that Myrmica scabrinodis is dominant in areas with more silt and salt in the soil, characterized by a vegetation with more typical halophytes, whereas Myrmica rubra occurs most frequently in sandy habitats without much salt stress. The populations of both Myrmica species and Lasius niger do not seem to be affected by inundation during winter.
The distribution of the ant species is discussed in relation to data about ants in more stable habitats. In particular, attention is given to the absence, in this coastal plain, of Lasius flavus which is a dominant species in the sand‐dunes and neighbouring parts of the salt‐marsh on Schiermonnikoog.
Intraspecific variation in food plant favourability to phytophagous insects: psyllids on Eucalyptus blakelyi M.
Authors: JOURNET ALAN R. P. 
Published: March 2008

Abstract.

A combination of variables reflecting leaf quality provided the best predictive model explaining differences in population trend of Glycaspis spp. among individuals of the food plant Eucalyptus blakelyi, measured under field conditions on an egg to egg basis. The equation incorporated the product of: (1) proportion of foliage in each age class; (2) probability of foliage escape from herbivory; (3) preference for the foliage class measured as the proportion of eggs oviposited on it by the female; these variables being summed over the young and mature age classes.
In addition, significant and consistent differences in insect survivorship among trees were demonstrated by transfer experiments. These experiments established that young foliage was preferable to mature foliage for first instar survival. Differences in insect survivorship also showed a consistent pattern among the study trees. The most probable explanation for this consistent pattern was the influence of the trees on the insects, particularly physiological or biochemical differences among trees. It was not, however, possible to identify the cause of the differences.
An attempt at re‐establishing the swallowtail butterfly at Wicken Fen
Authors: DEMPSTER J. P. , HALL M. L. 
Published: March 2008

Abstract.

Details of a reintroduction of the swallowtail, Papilio machaon, to Wicken Fen are given.
The introduced population expanded at first, but crashed as a result of the 1976 drought. It then failed to recover and is probably now again extinct on the Fen.
The changes in the habitat and the status of the butterfly's food plant, Peucedanum palustre, caused by the drying out of the Fen are discussed, and it is concluded that there is no chance of reestablishing the butterfly permanently at Wicken, unless the Fen can be made wetter.
The distribution in time and space of parasitism in Epinotia tedella (CI.) (Lepidoptera: Tortricidae)
Authors: MÜNSTER‐SWENDSEN M. 
Published: March 2008

Abstract.

The temporal and spatial distribution of parasitism in Epinotia tedella was investigated within two spruce stands.
Most eggs were laid by the host female early in the season. The parasitoid, Pimplopterus dubius, was subjected to a temporal stress, and it also exhibited a greater oviposition rate early in its life. The temporal distribution of attack frequencies by P.dubius and Apanteles tedellae showed a good adaptation to the phenology of the host.
The spatial distribution of flight activity indicated a preference to exposed sub‐habitats by P.dubius and to dark and sheltered sub‐habitats by A.tedellae. The distribution of host larvae showed an aggregation in the lower and central parts of the canopy, and so did the attacks by A.tedellae— even more pronounced. The attacks by P.dubius showed a slightly inverse aggregation pattern. Apparently, the distribution of attacks was caused by preference to physical conditions, rather than local host densities.
The decreasing log. area of discovery on increasing log. parasitoid density is obviously a ‘pseudo‐interference’ phenomenon caused by the aggregation of A.tedellae, and temporal asynchrony in P.dubius.
P.dubius dominated in young stands and its importance decreased with increasing age of the stands. The importance of A.tedellae was greatest in stands between 20 and 40 years old, and it dominated in those stands that were especially dense and dark, due to absent thinnings.
Colour patterns of Syrphidae. III. Sexual dimorphism in Eristalis arbustorum
Authors: HEAL J. R. 
Published: March 2008

Abstract. 1. The hoverfly Eristalis arbustorum L. (Diptera, Syrphidae) is a sexually dimorphic Batesian mimic of bees and wasps.2. This dual mimicry entails good mimicry of several small, dark bees (mainly mining bees) by female E.arbustorum, and less specific mimicry of wasps and other yellow and black Hymenoptera by males.3. There is also variability of colour pattern within both sexes of E.arbustorum.4. Seasonal fluctuations in the pattern frequencies of males occur because the temperature during pupal development influences the coloration of the adult.5. Temporal changes in the pattern frequencies of females are attributable to developmental darkening of the abdomen.6. These effects can be explained by the fact that the phenotypic requirements for thermoregulation and protection against predation will be different for males and females, and will also vary with time.7. Behavioural differences between males and females are a component of the sexual dimorphism in this species.
Habitat segregation among African treehole mosquitoes
Authors: LOUNIBOS L. P. 
Published: March 2008

Abstract. 1. The division of macrohabitats, seasons and microhabitats among mosquitoes which inhabit water‐filled treeholes was investigated in a wet/dry seasonal environment near the coast of Kenya. Twenty‐two species from four genera (Aedes fourteen, Culex three, Eretmapodites three, Toxorhynchites two) were identified from treeholes and bamboo traps. These included five which were more abundant in other microhabitats: leaf axils, fruit husks, or abandoned snail shells.2. Trapping in different vegetation zones or heights in forests revealed that all seventeen species examined showed opposition preferences for one or more macrohabitats. Segregation of related species by macrohabitat was particularly apparent among members of the subgenus Stegomyia of Aedes which accounted for 57% of individuals identified from one locality.3. Seasonal overlap was low between Aedes, which tracked rainfall patterns, and Culex and Eretmapodites. Aedes bromeliae differed from other Aedes found in treeholes in that maximal larval numbers did not follow heavy rainfall.4. Negative associations between Aedes fulgens and two congeners which co‐occur in the same forest and season were attributed to preferences for tree‐holes of different sizes. Positive associations between Aedes aegypti and several other Aedes were reduced when root buttresses, a subclass of larger treeholes containing more species, were removed.5. Separation of species by growth stages may be accomplished by two schemes of egg hatching which desynchronize larval cohorts in the same tree‐hole: the early pattern of Stegomyia whereby 50–95% of all eggs hatch at first immersion, and the delayed pattern of other subgenera (Diceromyia, Finlaya, Pseudarmigeres) in which less than one‐third of all eggs hatch at first immersion.6. The number of wet treeholes changed seasonally. During one year five or six periods occurred when 50% or more of the censused holes contained sufficient water for larval survival. The number of individuals and species of mosquitoes in treeholes were positively correlated with treehole volume. In a comparison of treeholes and their mosquito fauna from two forests, treehole volume and mean number of species per hole differed significantly, but mosquito density did not.7. Ecotonal trapping sites of mixed grasses, trees, and scrub yielded the highest mean numbers of species per sample, and traps placed outside a village, the lowest. Specific dominance was significantly less in the ecotone than elsewhere. The predatory larvae of Toxorhynchites brevipalpis in ecotonal and forested traps were not correlated with species richness.
The sex ratio in ectoparasitic insects
Authors: MARSHALL ADRIAN G. 
Published: March 2008

Abstract. 1. The sex ratio in 379 collections, each consisting of more than 100 individuals, of 250 different species of ectoparasite belonging to seven orders of insects is recorded. The data are gathered from a broad survey of published literature.2. In general, ectoparasitic insects emerge as adults in equal numbers of each sex, although there are certain exceptions.3. The sex ratio in natural populations may alter with numerous factors, but in general it is unbalanced, females usually predominating. Out of 359 collections from the host's body or home, the sex ratio of 30% showed no significant departure from unity, 63% contained significantly more females, and 7% significantly more males.4. These imbalances could be due to sampling methods but this is rare. Generally they are due to one sex, usually the male, being shorter lived than the other. This may be because males are often more active and smaller than females, and thus more likely to be separated from the host's body or home, succumb to host predation, or be killed by adverse climatic or nutritional conditions.
Interaction between insect larvae and tadpoles in tropical rain pools
Authors: McLACHLAN ATHOL 
Published: March 2008

Abstract. 1. Ephemeral rain pools on rock surfaces are common in Africa and are inhabited by dense populations of aquatic dipteran larvae. About 30% of the pools also support large numbers of tadpoles of the frog Ptychadena anchietae.2. Experiments reveal that the presence of tadpoles suppress eclosion of the rock pool dwelling midge Chironomus imicola.3. However, the presence of tadpoles also shortens the larval life‐span of C. imicola by speeding up growth rates. Since the larval stages must be completed before the pool dries tadpoles may help ‘fine‐tune’ the dipteran to the rock pool habitat.4. A change in the diet of Cimicola larvae is associated with the accelerated development. Grazing by tadpoles results in algae, growing on the water surface, reaching the mud in tadpole faeces. These algae represent a high protein and energy food not otherwise accessible to mud dwelling dipteran larvae.5. When pools dry tadpoles are killed, but a second species of dipteran Dasyhelea thompsoni have larvae able to survive to dry phase in situ. These larvae are scavengers so that on reflooding dead tadpoles are available as food. Experiments show that the presence of tadpoles again increase larval growth rates.6. Both alive and dead tadpoles therefore are responsible for increasing the quality and quantity of food available to dipteran larvae and are thus among the mechanisms ensuring an abundance of food for rock pool dwelling insect larvae.
The distribution and biology of Sepsidae (Diptera) in upland regions of northern England
Authors: RANDALL M. , COULSON J. C. , BUTTERFIELD J. 
Published: March 2008

Abstract. 1. A survey of the distribution of Sepsidae was made over 2 years at forty‐two sites in northern England. Material was collected by pitfall trapping and in sweep‐net samples.2. With the exception of a single specimen taken in a pasture, only members of the genus Sepsis were found and three species, S.cynipsea, S.orthocnemis and S.neocynipsea, occurred at most sites. The numbers of S.cynipsea were greater than S.orthocnemis at the great majority of sites. S.neocynipsea was the least abundant of the three species but occurred over the whole altitudinal range and formed a greater proportion of the catch at higher sites.3. It is suggested that the three commonest species use sheep dung as their main larval habitat in upland areas. Cow dung (the commonest reported larval habitat of Sepsis spp.) did not occur on any of the main sites studied. No sepsids were reared from red grouse droppings.4. There was no difference in the species composition on peat and grassland sites but almost 4 times as many sepsids were caught on the peat moor than on the neighbouring grasslands.5. There was a marked bimodal distribution of adults with a trough of captures in June and July. This is in contrast to data from other studies, at low altitudes, and is probably the result of there being only two generations per year in upland areas rather than four (or more) in warmer conditions.
The effect of temperature on the growth and reproduction of two closely related aphid species on sycamore
Authors: WELLINGS P. W. 
Published: March 2008

Abstract. 1. Egg hatch in the two species of sycamore aphid was temporally separated: the median time to hatch was 30 days later in Drepanosiphum acerinum than in D.platanoidis.2. D.platanoidis was larger at egg hatch than D.acerinum. Progeny of D.platanoidis adults were also larger than those of D.acerinum.3. D.platanoidis was the larger of the two species as an adult, as a consequence of its greater birth weight.4. Over a range of temperatures, development rates in the two species were the same, while the growth rate in D.acerinum was significantly higher at high temperatures.5. The reproductive rate of the two species was significantly different at 6d̀C and 20d̀C.
Foraging ecology of hoverflies: morphology of the mouthparts in relation to feeding on nectar and pollen in some common urban species
Authors: GILBERT FRANCIS S. 
Published: March 2008

Abstract.1. Previous accounts of the feeding behaviour of hoverflies (Diptera: Syrphidae) are contradictory and in many cases do not correspond with field observations.2. Patterns of feeding on nectar and pollen differ between species: these patterns are correlated with morphological differences.3. The data indicate that there are two correlates of increasing tongue length: first, the proportion of pollen in the diet decreases; and second, the flies concentrate on visiting flowers with longer corollae, which contain more nectar sugar.4. Reasons for these effects are discussed.
The life cycles and age of Carabus glabratus Paykull and C.problematicus Herbst (Col.: Carabidae) on moorland in northern England
Authors: HOUSTON W. W. K. 
Published: March 2008

Abstract. 1. The life cycles of C.glabratus and C.problematicus on moorland in northern England were studied in 1967. C.glabratus was a spring/summer breeder whilst C.problematicus was a late summer/autumn breeder and both had biennial life cycles.2. Mandible wear and reproductive condition were used to indicate the age of the adults; some females lived for at least 2 years and probably three, with a distinct regression of their ovaries between each breeding season.3. Mandible wear affected their ability to feed and thus build up fat reserves or develop eggs. Individuals with extreme mandible wear may die of starvation.
Patterns of abundance, distribution, and alary polymorphism among the salt marsh Delphacidae (Homoptera: Fulgoroidea) of Northwest Florida
Authors: McCOY EARL D. , REY JORGE R. 
Published: March 2008

Abstract. 1. The species of Delphacidae captured in nearly 16000 sweeps of salt marsh vegetation in Northwest Florida, U.S.A., are examined. Individuals belonging to fourteen species were captured during the 15‐month study, a somewhat larger number than is found in most locations.2. Abundances ranged from one to 1064 individuals per species. The abundances, habitat preferences, and patterns in wing‐polymorphism among the species collected were similar to those reported previously from other locations, but important differences were found which reflect the vegetational composition typical of our study area.3. Wing‐morph ratio differences between delphacid populations may reflect strategies for dealing with differences in stability and distribution of their respective habitats. The ratio of macropter/brachypter individuals in various populations of delphacids investigated correlates with the probability that a dispersing individual will find a more suitable habitat patch. The phenomenon is illustrated with a comparison of wing‐morph ratios in populations of Prokelisia marginata (Van Duzee) from locations which differ in the extent, distribution, and stability of their stands of Spartina alterniflora Loisl. (smooth cordgrass), the common host of P.marginata.4. Macroptery is favoured in Atlantic Coast marshes, where habitat patches are differentially suitable, but extensive and predictable. The probability of finding a better patch by dispersing is therefore high.5. Brachyptery predominates at Cedar Key, Florida, where habitat patches are extensive, stable, and equally suitable during most of the year; and at St Marks, Florida, where resource patches are small, infrequent, isolated, and regularly disturbed. Under these conditions, the probability of finding a better patch by dispersal is low.6. The conditions at St Marks may have promoted a local host expansion by P.marginata at this location.
Some aspects of the rate of increase of a coccinellid
Authors: MILLS N. J. 
Published: March 2008

Abstract. 1. Fecundity, growth and development were determined at a range of feeding levels and temperatures and compared with the component models for the predator rate of increase.2. Fecundity and growth rate show a linear dependence on rate of consumption, while development rate conforms to an alternative non‐linear model. The non‐linearity of development rate is due to a dependence of weight gain during an instar on rate of consumption.3. The primary influence of temperature is on the rate of consumption, limiting fecundity and growth rate at temperatures below the optimum for the stage, while higher temperatures have a deleterious effect. Temperature has a more direct influence on development rates, allowing comparable growth despite the variation in rates of consumption.
Intraspecific variability in herbivore performance and host quality: a field study of Uroleucon caligatum (Homoptera: Aphididae) and its Solidago hosts (Asteraceae)
Authors: MORAN NANCY 
Published: March 2008

Abstract. 1. Performances of two clones of Uroleucon caligatum on eleven clones of Solidago were measured by caging aphids on plants in the field.2. Several measures were obtained, including developmental time from birth to adulthood, size of first instar nymphs, adult weight, and total colony weight.3. All measures of performance were strongly affected by plant clone.4. Effect of aphid clone‐plant clone interaction was significant only for first instar size.5. In a subsequent screenhouse experiment, plant clones were subjected to uniform conditions and still exhibited large differences in host quality.
An ecological interaction between citrus fruit, Penicillium moulds and Drosophila immigrans Sturtevant (Diptera: Drosophilidae)
Authors: ATKINSON W. D. 
Published: March 2008

Abstract. 1. Potential Drosophila breeding sites were collected from a fruit market, and the adults allowed to emerge from them.2. D.immigrans and D.melanogaster were the species with the highest frequency of emergences from citrus fruit.3. D.immigrans was especially associated with citrus fruits infected with Penicillium italicum or P.digitatum, two specialist moulds of citrus. D.melanogaster was more often found in uninfected fruit.4. In the laboratory D.immigrans larvae survived better than D.melanogaster larvae on Penicillium‐infected citrus fruit.5. These adaptations suggest that D.immigrans may have originally evolved as a citrus specialist, becoming a domestic species as these fruits were exploited commercially.
Wind as a factor influencing flower‐visiting by Hadena bicruris (Noctuidae) and Deilephila elpenor (Sphingidae)
Authors: BRANTJES N. B. M. 
Published: March 2008

Abstract. 1. In a low‐speed wind tunnel, male as well as female moths of Hadena bicruris responded to floral odours with positive anemotaxis. Hitherto, such orientation has only been demonstrated for male moths in response to pheromones.2. H.bicruris had a maximum flight speed of 4.5–5.4ms‐1 and stopped its flower visiting at a wind speed of 2.5–2.8 m s‐1.3. Deilephila elpenor had a similar maximum flight speed (4.5— 5.1 ms‐1), but it continued visiting flowers up to wind speeds of 3.0–5.0 ms‐1.4. Apart from mechanical resistance during flight and flower visits, wind might have adverse effects on the energy budget and on evaporative water loss.