bluuebunny/crossref_metadata_2025 huggingface dataset:
Radar observations of concentrations of insects above a river in Mali, West Africa
Authors: REYNOLDS D. R. , RILEY J. R.
Published: March 2008

Abstract. 1. Radar observations are reported which demonstrate nocturnal accumulations of insects in the altitude range 30–130 m over some sections of the River Niger.

2. It is shown that on occasions when individual insect tracks were resolved, the accumulations were maintained by positive insect flight manoeuvres, and were not the result of passive response to air movement.

3. The mechanisms by which the insects might perceive the presence of the river are examined and it is deduced that at least some of the insects were able to detect the river boundaries by a visual or radiation sensing mechanism. It is noted that if the insects were using visual perception, their eyes must have been able to function in the absence of moonlight.

4. Evidence is presented which suggests that amongst the insects which contributed to the phenomenon were Ephemeroptera, and also larger insects, the latter becoming concentrated over the river in the course of migratory flight across the area.

5. Reasons why the insects accumulated over the river are discussed and it is suggested that the most probable strategies included the formation of mating swarms by some insects, and the use of the river by others as a linear feature to facilitate their orientation. It is also suggested that the insects may have been responding to differences in infra‐red radiation from the river and the bank, or to the warmer, moister air to be expected over the river.
Abundance and diversity of Homoptera in the canopy of a tropical forest
Authors: WOLDA HENK
Published: March 2008

Abstract. 1. A series of samples of Homoptera was obtained by fogging the canopy of Luehea seemannii trees in tropical forest in the Panama Canal Zone at three different times of the year.

2. The peak of abundance occurs around July (at least 11.8 individuals/m2), in the early wet season, at a time when most of the trees in the forest, including Luehea are producing new leaves.

3. Minimum abundance occurs in March (at least 3.5 individuals/m2), in the late dry season.

4. The samples obtained are some 35% richer in species per given number of individuals than light trap samples taken simultaneously in a similar forest some 6 km away from the present sampling site.

5. The data show that the effect of intensive light trapping on the populations of Homoptera in the forest is virtually negligible.

6. For a given sample size the tropical samples are many times richer in species than samples from temperate areas.
The application of X‐ray spectrometry to analysis of elemental composition (chemoprinting) in the study of migration of Noctua pronuba L.
Authors: BOWDEN J. , BROWN G. , STRIDE T.
Published: March 2008

Abstract. 1. Wavelength dispersive X‐ray fluorescence spectrometry was used to make quantitative determinations of the elemental composition (chemoprints) of individuals and of bulked males and females of Noctua pronuba.

2. Females caught in light traps at Rothamsted on two successive nights in August 1978 could be separated by significant differences in content of five elements, S, K, Ca, Cu and Zn. Two females, thought on biological grounds to be immigrants, could be distinguished from other, probably resident, females trapped at the same time.

3. Males and females were different in respect of four elements, S, Cl, K and Ca, three of which, S, K, and Ca, were also discriminants between nightly populations of females.
Avian predation on the palatable butterfly, Cercyonis pegala (Satyridae)
Authors: BOWERS M. DEANE , WIERNASZ DIANE C.
Published: March 2008

Abstract. 1. Samples from two populations of the satyrid butterfly, Cercyonis pegala were collected and analysed for palatability and incidence of avian predation.

2. A series of feeding experiments indicated that C. pegala is indeed palatable.

3. A high proportion of individuals in both samples showed evidence of avian attack: 10.2% in Amherst and 7.1% in Easthampton; this frequency is much higher than usually described for studies of this sort.

4. The two samples showed no significant differences with respect to frequency of damaged specimens.

5. There was no consistent location of damage on individuals or significant differences between the two samples.
The songs and calling sites of two European cicadas
Authors: CLARIDGE M. F. , WILSON M. R. , SINGHRAO J. S.
Published: March 2008

Abstract. 1. The male songs of two of the commonest cicadas in southern France are described with oscillograms.

2. Males of Cicada orni L. aggregate during calling whilst those of Lyristes plebeius (Scop.) space themselves out.

3. Both species are widely polyphagous on trees and shrubs, but L. plebeius sings from thinner stems than does C. orni

4. Such behaviour may result in the spatial separation of different species in the same habitat.
Observations on the foraging activity of Hospitalitermes umbrinus (Haviland), (Isoptera: Termitidae) in the Gunong Mulu National Park, Sarawak
Authors: COLLINS N. M.
Published: March 2008

Abstract. 1. A single nest of the black surface‐foraging nasute termite Hospitalitermes umbrinus was studied for 5 days in July 1978. Foraging parties of workers and soldiers tend to leave the nest in a continuous stream in the evening and return carrying food balls during the following morning.

2. An estimated maximum of 500000 individuals were involved in the foraging excursions. At a density of 3 nests ha‐1, the total foraging population is estimated as being at least 180 m‐2.

3. The colony brought back an estimated 46.4 g (d.w.) of food in 4 days. The biomass of the colony was estimated at 349 g (d.w.) (c. 1396 g w.w.) excluding alates and the consumption at 8.3 mg (d.w.) g‐1 (w.w.) d‐1.

4. The food balls were found to be of two types, light and dark coloured. The light balls contained wood constituents, bryophytes, blue‐green algae and fungal hyphae while the dark balls consisted mainly of lichens and their spores.

5. Swarming began at 14.30 hours on 9 July and ended with the nuptial flight at 17.32 hours. About 3000 alates were released. They climbed to 9 m on a tree before taking off.
Population estimates and dispersal of Hydrotaea irritans Fallén
Authors: ROBINSON J. , LUFF M. L.
Published: March 2008

Abstract. 1. Population estimates of Hydrotaea irritans were made by a mark and recapture technique at one site from 1976 to 1978.

2. Population densities of five to 200 thousand ha‐1 were found with large‐scale immigration and emigration occurring from the site.

3. The dispersal of marked adults from a point of release was rapid and marked flies were captured up to 3 km from the release point.

4. The distribution of flies along a woodland strip was not homogeneous; certain areas appeared to be more attractive and held more flies over a period of time.

5. The importance of the increasing area within which flies may be found as they move outwards from the release point is discussed.
Partitioning of resources by grassland leafhoppers (Auchenorrhyncha, Homoptera)
Authors: WALOFF N.
Published: March 2008

Abstract. 1. Resource utilization of time (i.e. seasonal occurrence of adults) and oviposition sites (i.e. heights of the host plant above ground level) have been analysed in five species of leafhoppers commonly associated with the grass Holcus mollis.

2. The d/w method proposed by May & MacArthur (1972) has been used and when the values for the two resources are examined together it becomes apparent that much potential competition for oviposition sites is reduced by segregation in time. Moreover, potential competition for common resources is reduced by mobility and dispersal of some species.
Natural pupation sites of swallowtail butterflies (Lepidoptera: Papilioninae): Papilio polyxenes Fabr., P.glaucus L. and Battus philenor (L.)
Authors: WEST DAVID A. , HAZEL WADE N.
Published: March 2008

Abstract. 1. Natural pupation sites have been found in Papilio polyxenes and P.glaucus by releasing prepupal larvae marked with UV‐fluorescent paint and locating them at night with a UV lamp, and in Battus philenor by searching a forest habitat where the larval foodplant is abundant.

2. P.polyxenes, a species of weedy habitats, pupates off the ground on a variety of substrates including grasses, weed stalks, posts, etc. The pupae may be green or brown, resembling the substrate.

3. P.glaucus, a species of forest habitats, pupates very close to the ground in the litter and has monomorphic brown pupae.

4. B.philenor, also a forest species, pupates on exposed surfaces (chiefly tree‐trunks or cliffs) well off the ground. Its pupae may be brown or green, but the latter were found only on the slenderest twigs.

5. The results for polyxenes and glaucus support the generalization of Clarke & Sheppard (1972) that species of stable habitats are likely to have monomorphic pupae, while those of habitats in which available sites may not be so similar from one generation to the next will be dimorphic.

6. B.philenor is more problematical, but its tendency towards pupal monomorphism (brown) is logical in relation to its common pupation sites.
Host plant specificity, oviposition behaviour and egg parasitism in some leafhoppers of the genus Eupteryx (Hemiptera: Cicadellidae)
Authors: STILING PETER D.
Published: March 2008

Abstract.

Three species of Eupteryx, E.aurata, E.cyclops and E.urticae are regularly found on stinging nettles in South Wales.

E.aurata host alternates between nettles in spring and autumn, and Heraclewn, Eupatorium and Mentha species in summer. E.cyclops and E.urticae attack only nettles.

All species are host specific during oviposition and show preferences to lay eggs in discrete plant regions.

A Mymarid egg parasite of the genus Anagrus was reared more commonly from eggs laid in nettles than from eggs laid in alternative hosts.
Density‐dependent changes in sex ratio in Colias lesbia (Lepidoptera: Pieridae)
Authors: BERNSTEIN CARLOS
Published: March 2008

Abstract.

The changes in sex ratio of a population of Colias lesbia were studied for four consecutive years.

A constant sex ratio was found in the samples taken in the 34 days following the last harvest of the alfalfa.

For the samples taken 35 or more days after the harvest the sex ratio decreases as the total number of adults caught increases.

The indirect evidence collected suggests that differences in emigration tendencies between sexes play a major role in determining the sex ratio in this species.
Invertebrate predation of leaf‐miners at low densities
Authors: FAETH STANLEY H.
Published: March 2008

Abstract.

Predation on a species of leaf‐mining insect, Eriocraniella sp., by two species of ants, Crematogaster ashmeadii Mayr and Pseudomyrmex brunnea F. Smith, is documented.

Exclusion experiments show that ants and other terrestrial invertebrates can greatly contribute to mortality of leaf‐miners and significantly decrease survivorship of the larval stages even when densities are low.

Comparison of two leaf‐mining species, Eriocraniella sp. and Cameraria sp. nov. Davis, indicates that factors of mortality depend on the maturity of the leaf being mined.
Ecological studies on the parasite complex associated with typhlocybine leafhoppers (Homoptera, Cicadellidae)
Authors: JERVIS MARK A.
Published: March 2008

Abstract.

The parasite complex associated with nymphal and adult typhlocybine leafhoppers consists of the following: Dryinidae (Aphelopus species), Pipunculidae (Chalarus species) and Diapriidae (Ismarus dorsiger Curtis), the last being parasitic on species of Aphelopus.

The life cycles and temporal distribution patterns of twenty‐nine species of Typhlocybinae are summarized together with the life cycles of British Aphelopus and Chalarus.

Closely related primary parasite species differ in their adult emergence times. Species differences in adult emergence times of diapausing Chalarus are correlated with species differences in host relations.

Each primary parasite genus contains both monophagous and polyphagous species. Each polyphagous species shows a distinct ‘preference’ for a particular range of hosts.

The parasite complexes of different leafhopper communities are compared, and it is concluded that it is the taxonomic composition of the leafhopper communities which is chiefly responsible for the structure and taxonomic composition of their associated parasite complexes.

Individual species of both Aphelopus and Chalarus show a degree of sensitivity to the physiology of their hosts, so achieving a high degree of synchrony.
Life budgets for a population of Tipula sacra (Diptera; Tipulidae)
Authors: PRITCHARD GORDON
Published: March 2008

Abstract.

A population of Tipula sacra was studied intensively from 1969 to 1974 in a series of abandoned beaver ponds. Beavers recolonized the ponds from 1974 to 1976 and again in 1978.

The basic life‐cycle is of 2 years duration, but cohort‐splitting occurs in the autumn as a result of some larvae growing faster and completing the life‐cycle in 1 year.

Some periods are more favourable for growth than others and the size of the fast‐growing cohort varies from year to year. This insight allows some anomalies in the estimates of population size to be explained and life budgets have been produced for three year‐classes.

The short‐fall in realization of egg potential is massive, apparently due to heavy female mortality by predation and the prevention of oviposition by inclement weather.

Mortality rate is relatively low and constant from stage II larvae until pupation, but increases to adult emergence. There is a correlation between larval density and mortality rate.

Certain aspects of the life‐history (e.g. high fecundity, variability in growth rate) appear to fit the species to life in a temporally unstable habitat.
Another look at prey detection by coccinellids
Authors: STUBBS MARY
Published: March 2008

Abstract.

Adult and fourth instar larvae of Coccinella septempunctata (L.) were tested to see whether or not they could detect prey prior to physical contact.

Adult predators found aphid prey and a silver foil dummy significantly faster than an X‐mark on the floor of the arena covering the same area.

Fourth instar larvae found crushed prey more quickly than the X‐mark but were not able to detect whole frozen prey.

The distances at which the predators could detect prey were calculated. This distance was found to be about 1.0 cm for the adults and 0.7 cm for the fourth instar larvae.
Taxonomic isolation and the accumulation of herbivorous insects: a comparison of introduced and native trees
Authors: CONNOR EDWARD F. , FAETH STANLEY H. , SIMBERLOFF DANIEL , OPLER PAUL A.
Published: March 2008

Abstract.

Evidence from leaf‐mining insects on Fagaceous hosts suggests that range expansions of insects onto introduced trees often involve species that feed on native hosts closely related to the introduced host.

An examination of the herbivorous entomofauna of British trees illustrates that the size of the entomofauna is partially determined by the taxonomic isolation of the host tree.
Adaptive dispersal and appetitive flight in the green lacewing, Chrysopa cornea
Authors: DUELLI PETER
Published: March 2008

Abstract.

The flight behaviour of Chrysopa cornea Steph. (Neuroptera: Chrysopidae) with regard to dispersal activity has been investigated in field experiments. There are three main types of flight activities.

Shortly after emergence (in the first two nights) the adults perform adaptive dispersal flights which are straight downwind flights mostly at elevations higher than 3 m above ground. The lacewings do not react to the presence of honey dew in the crop.

After 2—3 days the scent of honeydew becomes a strong landing stimulus. The flight is now an appetitive downwind flight which usually is lower than 3 m above ground.

Once landed, the lacewings' subsequent flights are toward the source of the kairomone which signals honeydew. This can be termed appetitive upwind flight. It is a low stepwise flight within the ‘boundary layer’ which rarely exceeds 1 m above crop level.

Dispersal takes place in a continuous ‘rolling’ downwind movement of the whole lacewing population. The immigration rate into a field is thus not a function of the quality of that field but rather of upwind fields. Emigration, however, strongly depends on the presence of honeydew (retaining of ovipositing immigrants) and the density of aphids or other food for the larvae (production of new adults).
Interactions between Apion species (Coleoptera: Curculionidae) and Polygonaceae. I. Apion curtirostre Germ, and Rumex acetosa L.
Authors: HOPKINS M. J. G. , WHITTAKER J. B.
Published: March 2008

Abstract.

Apion curtirostre is the commonest weevil attacking Rumex acetosa in the Lancaster area.

The ovipositional behaviour, larval development, emergence and hibernation of A. curtirostre are described.

From dissection of samples of stems of R. acetosa, abundance curves for the stages of A. curtirostre and its chalcid parasitoids were constructed and the between‐stage mortalities determined.

There is an exponential relationship between R. acetosa stem height and number of A. curtirostre eggs laid.

Male stems of R. acetosa appear earlier and are smaller than female stems. Taller stems, at least in female plants, live longer than shorter ones.

Apion survival is lower in male than in female stems.

Stem sex is the primary determinant of opposition choice with stem thickness a secondary determinant.

A. curtirostre eggs introduced experimentally into stems of four Rumex species survived significiantly better in R. acetosa than in any other species. Survival in R. acetosa female plants was twice that in males.

Survival of A. curtirostre eggs at densities of 4, 8 and 16 per R. acetosa stem was twice that at densities of 32 and 64 per stem.

The stem size of female R. acetosa was reduced as the number of attacking weevils increased. There was no significant effect in males. No adverse effect on seed production was detected.

The nature of the relationship between A. curtirostre and R. acetosa is discussed.
Interactions between Apion species (Coleoptera: Curculionidae) and Polygonaceae. II. Apion violaceum Kirby and Rumex obtusifolius L.
Authors: HOPKINS M. J. G. , WHITTAKER J. B.
Published: March 2008

Abstract.

The biology of Apion violaceum is described, particularly with respect to its primary host, Rumex obtusifolius.

Oviposition in Rumex acetosa is directly into the stem, but in R. obtusifolius it takes place through the sheath enclosing developing flowers, stem leaves and stem.

Larvae cannot complete development in the leaf petioles and must migrate downwards to the stem or die before pupation.

Mortality of A. violaceum in the stems was highest in eggs and first instar larvae and in third instar larvae. The latter mortality was caused almost entirely by parasitoids.

Stems of R. obtusifolius on the study site increased in number up to August and reached the maximum height in late June.

Over the 4 year study period there was a parallel decline in stem numbers and mean stem height at two of the sites studied. At these sites there was also a decline in A. violaceum numbers and density per stem.

The quality of sites for A. violaceum, as defined by the product of stem numbers and stem height, showed a significant correlation with A. violaceum numbers.
Recapture studies of the harvester ant, Pogonomyrmex owyheei Cole, using a fluorescent marking technique
Authors: PORTER SANFORD D. , JORGENSEN CLIVE D.
Published: March 2008

Abstract.

Mark—recapture sampling must be stratified because populations of foragers and defenders are partitioned by trunk trails and order of emergence respectively.

Foragers and defenders form overlapping subsets of the total colony population, each of which is correlated with total colony population size.

Foragers and defenders have an average life expectancy of approximately 2 weeks.

The fluorescent marking procedure did not significantly affect harvester ant mortality and only temporarily affected their behaviour.

Combinations and mixtures of fluorescent ink allow at least eight groups in a colony to be distinctly marked for periods exceeding 4 months.
The life history of Philanisus plebeius Walker (Trichoptera: Chathamiidae), a caddisfly whose eggs were found in a starfish
Authors: WINTERBOURN M. J. , ANDERSON N. H.
Published: March 2008

Abstract.

Philanisus plebeius had a univoltine life cycle with adults present from November to April in the South Island of New Zealand. Males predominated in light trap collections in all months and the mean size of adult insects declined over the flight period.

There are probably seven larval instars which inhabited the marine intertidal zone and fed primarily on non‐calcareous algae. Pupae were found only on the red alga, Corallina officinalis.

Caddisfly eggs were found during most of the year in the coelom of an intertidal starfish, Patiriella regularis. Oviposition is probably through the popular pores and newly hatched larvae may leave the host via the same route or through the stomach wall.

Egg development time was greater than 30 days at 16–18°C.

P.plebeius probably colonized New Zealand from Australia after the unusual oviposition behaviour had evolved in association with the Australian cushion star, Patiriella exigua. P.regularis is less abundant and occurs lower on the shore than P.exigua and may be inaccessible to some caddisflies which oviposit amongst intertidal algae.
The relation between body size and resistance to desiccation in two species of Zaprionus (Drosophilidae)
Authors: BARKER JOHN F. , BARKER ANTJE
Published: March 2008

Abstract.

Resistance to desiccation and body size were studied in the drosophilid flies Zaprionus vittiger and Z.tuberculatus.

Populations in a hot dry low altitude area were compared with those in a nearby cooler wetter high altitude area in the north‐eastern Transvaal of South Africa, using laboratory strains established from these populations.

No between‐area differences were found for either body size or resistance to desiccation considered separately.

However, in Z.tuberculatus, regression analyses using strain mean values showed a strong positive correlation between the two characters amongst strains derived from low altitude populations but not amongst strains derived from high altitude populations.

It is concluded that differences of genetic organization have evolved between low and high altitude populations of Z.tuberculutus.

From differences between species and sexes it is concluded that both body size and some unknown factor related to sex may influence resistance of desiccation.
The reproductive biology and diapause of the British fungal‐breeding Drosophila
Authors: CHARLESWORTH PAUL , SHORROCKS BRYAN
Published: March 2008

Abstract.

Seasonal reproductive development was investigated in four obligate fungivorous species, D.phalerata Meigen, D.transversa Fallen, D.cameraria Haliday and D.confusa Staeger.

Samples of females taken from woodlands over a 2 year period were scored for reproductive status and fat content.

Populations of D.phalerata and D.cameraria maintained in an outdoor insectary provided information on developmental time and adult mortality throughout the year.

Experiments in controlled environmental chambers gave percentage diapause curves against day length for all four species.

In D.phalerata the influence of temperature and fungus upon diapause behaviour was also investigated.

In D.phalerata the optimal strategy for reproductive development can vary from month to month. Maturation of females may be immediate, dependent upon a fungal cue or completely prevented.
Susceptibility of Scaevola taccada (Gaertn.) Roxb. bushes to attack by the coccid Icerya seychellarum Westwood: the effects of leaf loss
Authors: HILL M. G.
Published: March 2008

Abstract.

The distribution of infestation levels of the coccid Iceryu seychellarum on bushes of Scuevola taccudu and its population fluctuations over a 10 month period on Aldabra atoll show that individual plants of S. taccada exhibit differential susceptibility to attack.

Coccids on heavily and lightly infested bushes show no important differences in growth rate, fecundity or plant induced death rate. There were also no demonstrable differences in bush exposure, food quality (total and soluble nitrogen levels) or settlement behaviour of first instar larvae (crawlers).

Detailed examination of Iceryu populations on individual leaf clusters showed that mortality caused by leaf fall is density dependent and can be avoided only if a large proportion of the population frequently moves from senescing to mature leaves. The proportion of the population required to move to younger leaves in order to complete development is greater in low density Zceryu populations.

The effects of leaf fall are discussed with reference to the maintenance of differential susceptibility within the plant population.
Foraging patterns in three sympatric forest ant species, Prenolepis imparis, Paratrechina melanderi and Aphaenogaster rudis (Hymenoptera: Formicidae)
Authors: LYNCH JAMES F. , BALINSKY EDWARD C. , VAIL STEPHEN G.
Published: March 2008

Abstract.

Ecological segregation was studied in Aphaenogaster rudis Emery, Paratrechina melanderi (Wheeler) and Prenolepis imparis (Say), the three commonest surface‐foraging ants in a Maryland (U.S.A.) hardwood forest community.

P.imparis retreats from the surface during mid‐summer, but shows more cool‐season activity than do the other two species. P.melanderi is most active during the warmest months of the years. A.rudis is the most generalized of the three species in its seasonal activity pattern.

P.imparis is a highly aggressive species which forms large mobilizations at rich food sources. P.melanderi is a timid species which forms small mobilizations. A.rudis is intermediate in both respects.

Based on the results of baiting trials, P.imparis shows an apparent preference for protein‐fat food, P.melanderi prefers carbohydrate food, and A.rudis exhibits no significant preference for either fclod type.

As a result of its extended seasonal activity, weak circadian periodicity, and lack of food specialization, A.rudis has the broadest annual niche of the three species studied.

The unusual seasonal activity pattern of P.imparis results in a relatively low degree of annual niche overlap between this species and either of the other two. Overlap between A.rudis and P.melanderi is substantially higher.

Experimental manipulations confirm that rates of resource removal by a behaviourally subordinate species (Amdis) are reduced in the presence of a dominant species (P.imparis).

Persistence of these three widespread, abundant, relatively generalized ant species in local sympatry may in part reflect their differential success in: (a) finding food, (b) defending food, and (c) handling food items of different sizes.
Latin Square designs in field experiments involving insect sex attractants
Authors: PERRY J. N. , WALL C. , GREENWAY A. R.
Published: March 2008

Abstract.

Interactions between insect sex attractant traps are of ecological interest in themselves, but may cause problems in field experiments in which attractants, or control measures, are compared quantitatively.

Some of these problems are solved by experimental designs based on the Latin Square.

The applicability of the designs to research involving comparison of attractants, effectiveness of control measures and attractant trap interactions is discussed, and examples are given with field data.

Efficiencies of different designs are compared using data from fifteen experiments.

Disadvantages and extensions of the design are discussed.

Latin Square designs are simple, practical, and usually more efficient than other designs.
Coexistence of two species of Binella Motchulsky (Coleoptera: Ptiliidae) and the significance of their adaptation to different temperature ranges
Authors: TAYLOR VICTORIA A.
Published: March 2008

Abstract.

Ptinella aptera and Ptinella errabunda often coexist where their distributions overlap.

The ecological requirements of P.aptera and P.errabunda are similar. Both are generalized mycetophages restricted to the same subcortical habitat of trees in a particular state of decay. Relative humidity appears important in determining habitat suitability for both species, neither of which survived in laboratory regimes below approximately 100% relative humidity.

In laboratory studies the beetles differed in their response to temperature. Recorded maxima for activity and rate of increase were at higher temperatures for P.aptera than for Perrabunda.

Temperatures which ‘Ptinella were exposed to in the laboratory occur in natural conditions under bark. Their effects on the species’ distributions are considered.

The differential temperature adaptations of P.aptera and P.errabunda were probably evolved in allopatry, in response to different environmental conditions. In view of this, it is unreasonable to infer past interspecies competition from these niche differences.

The niche difference between coexisting Ptinella species is discussed in the light of current ideas concerning the relative importance of competition and other factors in natural communities.
Cohort studies on mosquito (Diptera: Culicidae) larvae living in the water‐filled floral bracts of Heliconia aurea (Zingiberales: Musaceae)
Authors: SEIFERT RICHARD P. , ROBERTO BARRERA R.
Published: March 2008

Abstract. 1. An experimental and observational study of the three species of mosquito larvae living in the water‐filled floral bracts of Heliconia aurea at Rancho Grande, Venezuela, was designed to determine if each mosquito species forms instar cohorts and excludes conspecifics of younger instars. This study was motivated by a statement of Maguire (1971) who suggested that mosquito larvae in Puerto Rican Heliconia inflorescences form instar cohorts and exclude younger mosquitoes from the floral bracts.

2. Field observations of naturally occurring populations of mosquito larvae from fifty‐three H.aurea inflorescences give no indication that cohorts are formed for Wyeomyia felicia and Culex bihaicolus. However, there is strong evidence that cohorts of Trichoprosopon digitatum occur. These cohorts are not structured by larval competition but by female preference of the youngest bracts as oviposition sites and by large T.digitatum larvae feeding on smaller con‐specifics.

3. Field experiments show that first instar W.felicia and C.bihaicolus survive as well over a 6 day period in the presence of third instar conspecifics as they do when all mosquito larvae in an experimental bract are first instars.
Effects of host needle age on the settling behaviour of two morphs of Adelges cooleyi (Gill.)
Authors: SPIRES S.
Published: March 2008

Abstract. 1. On Douglas fir progredientes of A.cooleyi migrate onto current‐year needles whereas the later‐hatching sistentes settle on older needles. The behaviour of these two morphs was compared in the laboratory.

2. The track length of progredientes was slightly greater than that of sistentes, but the tracks of the two morphs did not differ in terms of degree of irregularity or linear displacement.

3. Progredientes preferred current‐year needles whereas sistentes preferred previous‐year needles, especially on young branches.

4. Probing by sistentes was strongly inhibited on young current‐year needles.

5. This appears to be the first report in which two morphs of a single insect species on one host species prefer foliage of different ages.
Host plant associations, diversity and species—area relationships of mesophyll‐feeding leafhoppers of trees and shrubs in Britain
Authors: CLARIDGE M. F. , WILSON M. R.
Published: March 2008

Abstract. 1. Sixty‐two British species of Typhlocybine leafhoppers are known to feed on the leaf‐mesophyll tissue of trees and shrubs. British host records for fifty‐five of these are given.

2. The leafhopper faunas of thirty‐six species of native and introduced trees and shrubs are described.

3. The Shannon‐Wiener equation was used to calculate species diversity for adult samples collected from twenty different species at sixteen different localities in Wales, southern England and northern Scotland.

4. Sørensen's coefficients were calculated for rearing data from Britain generally, and subjected to cluster analysis. Most trees have low similarities with respect to leafhopper faunas and are quite distinct. Taxonomic relationships of trees appear to be relatively unimportant in determining the similarities of their leaf‐hopper faunas.

5. Using the same data, species—area relationships were calculated for thirty‐four different tree and shrub species and their associated leaf‐hoppers. A significant regression was obtained, but it explained only 16% of the variation. It is thus suggested that host plant range is relatively unimportant in determining the numbers of these species associated with different trees in Britain.

6. Some introduced species of trees, particularly the recently planted Nothofagus, have acquired large leafhopper faunas.
Sex ratio and adult behaviour of the Antarctic midge Belgica antarctica (Diptera, Chironomklae)
Authors: EDWARDS JOHN S. , BAUST JOHN
Published: March 2008

Abstract. 1. The sex ratio in populations of the Antarctic chironomid Belgica antarctica approximates 1:1 at eclosion.

2. Male predominance in surface populations of the short‐lived adult persists throughout the summer. The mean ratio, based on data from surface aggregations (austral summer 1977–78) and from sticky traps (1978–79) is about 6:1, with a steady seasonal decline from 10–20:1 to 2–5:1.

3. Males live slightly longer than females but the difference does not account for observed ratios.

4. Samples of adult populations taken from subsurface sites have sex ratios nearer to equality than surface populations.

5. It is concluded that the male‐dominated surface populations are equivalent to the male swarms typical of winged Chironomidae.

6. Capture of airborne adults shows that aerial transport as well as water‐surface rafting may play a role in dispersal of adults.
The influence of age and season on dispersal and recapture of Anopheles culicifacies in Sri Lanka
Authors: RAWLINGS P. , CURTIS C. F. , WICKRAMASINGHE M. B. , LINES J.
Published: March 2008

Abstract. 1. Three mark—release—recapture experiments with Anopheles culicifacies were carried out at different seasons in Sri Lanka. Blood fed females were collected daily in cattle baited huts, marked with fluorescent powder and released in the same village. In two of the experiments males and females were reared, marked when newly emerged, and released. The recapture rates were recorded in the same village and in a second village 2 km away.

2. The mosquitoes marked when already mature yielded an estimate that 2–7% of the mosquitoes in the second village had flown from the first. The recapture rate of reared mosquitoes in the first village was much lower than with those marked when already mature. This difference could be at least partly attributed to a tendency to disperse when young, as shown by the considerable number of recaptures of young mosquitoes in the second village.

3. By varying the colour used for marking, estimates were made of the amount of dispersal from hut to hut in the first village, the daily survival rate and the proportion of the wild population resting in the collecting huts each day.

4. Using the latter two estimates equations have been solved predicting the rate of build‐up of the proportion of recaptures. These predictions were compared with the observed results. The data on dispersal are discussed in relation to possible method for delaying the build‐up of insecticide resistance.
Plant tannins and insect herbivores: an appraisal
Authors: BERNAYS E. A.
Published: March 2008

Abstract. 1. The bioassays with tannins and insects, and the ecological studies on insects implicating tannins, are summarized and discussed.

2. Because of the great variation now shown in all aspects of the insect‐tannin relationship, the difficulty of making generalizations is stressed.

3. The significance of plant tannins for insect herbivores is reconsidered in the light of recent work and little‐known older work, which illustrate the very varied nature of its effects.
The nesting biology and population dynamics of the Seychelles potter wasp Eumenes alluaudi Perez
Authors: BROOKE M. DE L.
Published: March 2008

Abstract. 1. The nesting biology of the solitary potter wasp Eumenes alluaudi was studied on Cousin Island, Seychelles.

2. Although the rainy season was from October to April there was no indication of strong seasonality in the wasps' nesting.

3. Females tended to nest close to where other females were nesting.

4. The mean number of cells per nest was 3.71, the mean number of nests made per female 135, and the percentage of cells from which adults emerged 65.87; thus the mean number of adult wasps emerging from the nest(s) of each breeding female was 3.29.

5. Male‐producing eggs were laid before female‐producing eggs and the estimated sex ratio at emergence was, at 1:2.52, female biassed. It is possible that inbreeding occurred.

6. Daily mortality of nesting females was estimated as 0.088.

7. The mean interval between a female's emergence and her starting to nest was 19.7 days.

8. Marking showed that only 26.7 ± 6.3% of females emerging from cells in the study area returned to breed there. Since the number of emerging daughters per breeding female was only 5.01 times 0.66 times 0.72 = 2.36 (fecundity x proportion emerging x proportion of females emerging), the number of returning females would be only 236 times 0.267 = 0.63, and hence, in order to maintain numbers over many generations, 037 females must have been immigrants.
Abundance and survival of a seed‐infesting weevil, Pseudanthonomus hamamelidis (Coleoptera: Curculionidae), on its variable‐fruiting host plant, witch‐hazel (Hamamelis virginiana)
Authors: STEVEN DIANE DE
Published: March 2008

Abstract. 1. The relative importance of seed abundance and of mortality factors in the population biology of Pseudanthonomus hamamelidis, a hostspecific predispersal seed predator on Hamamelis virginiana, is evaluated by analysis of weevil life tables and abundance estimates in three years with markedly different magnitudes of fruit production.

2. Fruit production of marked Hamamelis individuals averaged 336 m‐2 in 1978, increased three‐ to four‐fold in 1979, and declined again in 1980. More individuals fruited in 1979 than in the other two years.

3. The early larval stage of P.hamamelidis incurred the greatest mortality, with 42–58% dying from often undeterminable causes. Losses in the egg stage ranged from 22% to 31%. Three parasitoid species each accounted for minor mortality. Generation survival was similar in all three years, ranging from 21% to 28%.

4. The percentage of Hamamelis fruit crops infested by P.hamamelidis was high in 1978, averaging 76%, but was much lower in 1979, the year of abundant fruit. In 1980, when fruit were less abundant again, infestation was nearly complete. Egg densities on fruits were lower in 1979 than in the other two years.

5. The fluctuating fruit crops of Hamamelis are responsible for limitation of P.hamamelidis numbers during poor fruiting years. The occasional highly productive fruiting year results in satiation of weevil populations and concomitant seed escape by Hamamelis. Mortality factors appear less important in influencing weevil population dynamics.
Relation of oxygen consumption to size and temperature in desert arthropods
Authors: MISPAGEL MICHAEL E.
Published: March 2008

Abstract. 1. Oxygen consumption was determined for ninety‐three taxa of desert‐inhabiting arthropods of various life stages over the temperature range 10–40d̀C. Regression analysis of O2 consumed/individual/h on the mean dry weight of individual adult insects yielded a slope of 0.70 (r= 0.87) while the same analysis for non‐insect arthropods gave a slope of 0.74 (r ‐ 0.87).

2. Average Q10 for all insects was 2.16 ± 0.66 over the 10–40d̀C temperature range. Q10was not significantly different among orders of arthropods at each 10d̀ temperature interval but decreased significantly with an increase in temperature.

3. Per cent water content ranged from a mean of 60% for Coleoptera to 78% for Lepidoptera larvae and indicated the necessity of using dry weight values in analyses of the relationship between size and oxygen consumption rates.

4. Models are supplied for each taxon to calculate the minimum energy for basic metabolism of field populations per unit time and area.
Successful and unsuccessful development of colonies ofVespula vulgaris(Linn.) (Hymenoptera: Vespidae)
Authors: ARCHER MICHAEL E.
Published: March 2008

Abstract.

Six categories of immature and five categories of mature colonies are described and their developmental relationships suggested.

Mature brood destroyed by the workers became numerous in 46.4% of the immature colonies. Most of these formed unsuccessful colonies (36.9%) producing few or no queens. The remaining 9.5% recovered to form successful colonies.

Successful colonies either reared queens only (mean 356 queens), or queens (mean 1461) and males (mean 254) in their large cells.

The number of small cells in mature colonies correlated with the number of cells built by the founder queen.

The greater the number of large cells in a mature colony the greater were the chances that a larger proportion of these cells would be used to rear adults.

The number of small and large cells are correlated in mature successful colonies.

Queen activity and quality are important factors in the control of colony size and success.

Selective destruction of male sealed brood in the large cells is linked to worker, rather than queen, control.
Patterns of herbivory on Passiflora leaf tissues and species by generalized and specialized feeding insects
Authors: DENNO ROBERT F. , DONNELLY MAUREEN A.
Published: March 2008

Abstract.

The feeding patterns of specialized (Heliconius butterflies) and generalized (the grasshopper, Osmilia flavolineata) herbivores on leaf age classes and species of neotropical vines in the genus Passiflora are compared by offering them leaf discs in choice experiments.

Heliconius larvae selected young meristematic leaves over medium aged and mature leaves of Passiflora auriculata on which to feed.

Adults of O. flavolineata consumed more young leaves of P. pittieri from an array of different ages of leaf tissue, but showed no preference for young over mature leaves of P. tetrastylus or P. data.

In choice tests conducted with medium aged leaves of four species of Passiflora, O. flavolineata selected P. tetrastylus over P. pittieri and P. vitifolia, which were consumed more than P. alata.

P. alata, which was avoided by O. flavolineata in feeding trials, was the only abundant Passiflora in neotropical habitats where generalized herbivores (grasshoppers and katydids) were common.

Our results suggest that Passiflora species in forest habitats where some generalized herbivores are rare have fewer chemical defences, but retain physical defences (tough leaves and hooked trichomes) rendering them unpalatable to specialized herbivores like the larvae of Heliconius butterflies.
The feeding behaviour of two leafhoppers on Vicia faba
Authors: GÜNTHARDT M. S. , WANNER H.
Published: March 2008

Abstract.

The feeding behaviour of the two Typhlocybinae Empoasca decipiens Paoli and Eupteryx atropunctata Goetze and the nature of the damage caused to Vicia faba L. were investigated.

Sections with stylets in situ, i.e. within the plant, were obtained. Eupteryx atropunctata sucked mainly from the palisade parenchyma of the leaf, while several generations of Empoasca decipiens could also live from the stem parenchyma and pierced into phloem if this was reachable.
Acoustic competition in bush crickets
Authors: LATIMER W.
Published: March 2008

Abstract.

The bush crickets Platycleis albopunctata (Goeze) and Metriop‐tera roeselii (Hagenbach) interact acoustically in the laboratory. The interaction is principally one‐way, resulting in modification of the song pattern of P. albopunctata or its inhibition. Similarity of the frequency spectra of songs of both species is one of the principal reasons for reactivity.

Nymphal male P. albopunctata individuals are randomly distributed in dense Brachypodium pinnatum L. grasslands. Adult males become regularly spaced with the onset of singing activity. Acoustic behaviour is the most likely mechanism maintaining regular spacing within the male P.albopunctata population.

In many localities juvenile P. albopunctata and M. roeselii are sympatric, occurring together in the same vegetation.

With the onset of singing activity by the adult males the two species separate though there is no detectable difference in habitat preference.

The separation is effected by a negative phonotactic response by P. albopunctata to the song of M. roeselii. It is suggested that this response is derived from behaviour patterns that result in ‘territorial’ spacing within the P. albopunctata (male) population.

This behaviour prevents the occurrence of song modification in the field but also excludes P. albopunctata from areas of suitable habitat where the population density of M. roeselii is high.
Population fluctuations of mosquitoes in the non‐seasonal tropics
Authors: WOLDA HENK , GALINDO PEDRO
Published: March 2008

Abstract.

Seasonal and annual fluctuations in abundance of a number of species of mosquitoes were studied in a relatively non‐seasonal climate near Almirante, Panama.

The fluctuations observed were large, but did not have a period of 1 year and should be classified as non‐seasonal.

At each site the various species were not synchronous in their fluctuation pattern, but the fluctuations of each species were synchronous over an area of at least 4 km long, in spite of large differences in habitat.

Changes in abundance from year to year observed in these mosquitoes are large compared with those of insects, including mosquitoes, in other areas of Panama.

The importance of such large and unpredictable fluctuations in abundance for planning control measures is discussed.
Insect herbivore guilds and species—area relationships: leafminers on British trees
Authors: CLARIDGE M. F. , WILSON M. R.
Published: March 2008

Abstract. 1. 239 species of leafmining insects have been recorded from thirty‐seven species of trees and large shrubs in Britain.

2. A significant species—area relationship was obtained for these insects, but it explained only 19% of the variation about the regression he. A further 23% of the variation may be accounted for by taxonomic relationship of host plants.

3. A significant correlation was established between the number of species of leafminers and those of mesophyll‐feeding leafhoppers for twentyeight host tree species. Both guilds are dominated by host specific feeders.

4. It is suggested that species—area effects are important in determining species richness of phytophagous insects mainly when groups of closely related host plants are considered. With more diverse arrays of hosts, taxonomic influences, which are probably mainly chemical, may outweigh such area related effects.