bluuebunny/crossref_metadata_2025 huggingface dataset:
Aspects of the symbiosis of the leaf‐cutting ant Acromyrmex octospinosus (Reich) and its food fungus
Authors: QUINLAN R. J. , CHERRETT J. M.
Published: March 2008

Abstract. 1. Laboratory ants preferred eating whole ant fungus staphylae to hyphae, and did not feed on other fungi. Homogenized ant fungus staphylae and hyphae were equally acceptable liquid food but other homogenized fungi were not drunk extensively.

2. Various arthropod fungjvores preferred to feed on ant fungus rather than any other fungus tested. Some preferred hyphae to staphylae, some vice versa and others had no preference.

3. The ants attacked animals on the nest and reduced the numbers of fungivores on the fungus garden.

4. The ant fungus grew best at 24.5°C and hardly at all at 10°C or 37°C.

5. The ants did not necessarily choose material which supported the best fungus growth in sterile culture and readily accepted substrates on which the fungus did not grow at all. No learning behaviour was noted.

6. The ant X fungus symbiosis is discussed as an example of co‐evolution, a product of an evolutionary feedback. The ant is supplied with a highly nutritious, readily acceptable food source in return for complex fungus‐culture behaviour, providing protection from fungivores and competition from other saprophytic fungi.
The oviposition sites of five leafhopper species (Horn. Auchenorrhyncha) on Holcus mollis and H.lanatus
Authors: THOMPSON P.
Published: March 2008

Abstract. 1. A study was made of the oviposition sites of five leafhopper species Diplocolenus abdominalis, Recilia coronifera, Errastunus ocellaris, Elymana sulphurella (Cicadellidae) and Dicranotropic hamata (Delphacidae) on the grasses Holcus mollis and H.lanatus.

2. Experiments were made in the laboratory, each insect species being provided simultaneously with a complete plant of both Holcus species.

3. Distribution of eggs within the leaf sheath and leaf blade, and their height above ground‐level, were recorded.

4. The presence and size of egg groups were noted, as well as the angle of eggs to the longitudinal axis of the leaf.

5. On the basis of comparison of the vertical distribution of the eggs with availability of plant tissues, the five species can be divided into three groups: (a) D.abdominalis and R.coronifera, (b) D.hamata and E.ocellaris, (c) E.sulphurella. Species within a group, i.e. with similar distributions of eggs, have other features separating their oviposition sites.
Population dynamics of the yew gall midge Taxomyia taxi (Inchbald) (Diptera: Cecidomyiidae)
Authors: REDFERN M. , CAMERON R. A. D.
Published: March 2008

Abstract. 1. The causes and incidence of mortality in populations of the yew gall midge Taxomyia taxi at Kingley Vale, West Sussex, are described in relation to the various life cycles of the midge.

2. Life table analysis of populations studied for 10 years indicates that the key factor in mortality is failure to achieve maximum fecundity, although in 1‐year life cycles parasitism by Mesopolobus diffinis is equally important. Densities and mortality vary considerably between different life cycles, and no regulation has been firmly established.

3. Interactions between the host populations and their parasites are complex and as yet not fully analysable, but the pattern of parasitism seen may explain some of the complex life history pattern of the host. The existence of long‐term cycles of host and parasite densities are predicted.
Population dynamics of two hymenopteran parasites of the yew gall midge Taxomyia taxi (Inchbald)
Authors: CAMERON R. A. D. , REDFERN M.
Published: March 2008

Abstract. 1. The densities of the hymenopteran parasites Torymus nigritarsus and Mesopolobus diffinis are determined mainly by the density of available hosts, Taxomyia taxi.

2. Area of discovery of T.nigritarsus is negatively related both to density of available hosts and to the density of searching parasites. Implications for the foraging strategy of T.nigritarsus are discussed.

3. Mesopolobus diffinis preferentially parasitizes hosts in the small 1‐year galls. This and other evidence suggests that not all galls are equally available for parasitism.
The distribution and movement of apterous Myzus persicae on rapidly growing turnip plants
Authors: HODGSON C. J.
Published: March 2008

Abstract. 1. The spatial distribution of both adult apterous and nymphal M.persicae was related to the “age” of the leaf.

2. This distribution was bimodal and was maintained even on rapidly “ageing” leaves by frequent emigration.

3. The spatial distribution was also found to change between regions of a leaf, the densest populations occurring at the base of all leaves, but with the populations most evenly distributed on the young and old leaves.

4. The spatial distribution also changed during the nymphal period, the youngest nymphs being found predominantly on the lamina, the fourth instar and adults on the largest available veins.

5. On rapidly growing plants, individual M.persicae may move to a new feeding site as frequently as every 24–48 h.

6. Some of the causes and consequences of this frequent dispersal are discussed.
Oppositional responses to host density in Aphytis holoxanthus (Hymenoptera: Aphefinidae), an efficient gregarious parasite
Authors: PODOLER HAGGAI , ROSEN DAVID , SHARONI MICHAL
Published: March 2008

Abstract. 1. Ovipositional responses of an efficient gregarious ectoparasite (Aphytis holoxanthus) to increasing densities of its host (the Florida red scale, Chrysomphalus aonidum, Homoptera: Diaspididae) were studied in a laboratory system.

2. The female parasite may lay one to several eggs at each encounter with a host.

3. As host density increased, the number of eggs laid by the female parasite during the experimental period increased at a decreasing rate. This type of functional response resulted in less parasitism at higher host densities.

4. As host density increased, the number of eggs laid per encounter decreased. This behavioural response partially compensated for the decrease in parasitism.
Life cycle and population dynamics of Trochosa terricola Thorell (Araneae: Lycosidae) in a Norfolk grass heath
Authors: WORKMAN CHRISTOPHER
Published: March 2008

Abstract. 1. The population of the lycosid Trochosa terricola Thorell was sampled from April 1973 to August 1975 at Weeting Heath NNR, a Breckland grass heath.

2. Four sampling methods were compared for efficiency. Hand searching gave density estimates between 38.3 and 70.1% of heat extraction.

3. The temperature range in the sward at +1 cm was –5°C to 39°C with January and July means of 3.2°C and 17.4°C.

4. Eight male and nine female instars were determined and the life cycle extended over 2 or 3 years.

5. Adults were nocturnal but the juveniles diurnal. An annual diplochrone activity pattern was observed for adult males.

6. The horizontal distribution within the sward was aggregated, the structure and microhabitat being important determining factors. The population density was greater in moist, young Festuca spp. tussocks. An equation relating population density to habitat characteristics was derived.

7. The overall population density ranged from 14.0 m‐2 to 76.0 m‐2 and was maximal in autumn after breeding. The population biomass was greatest during autumn (291.2 mg d.wt m‐2).

8. Mean number of juveniles emerging from an egg sac was 77.3 (first sac) and 38.0 (second sac). The natality in 1973 was 66.8 individuals m‐2.

9. The survivorship curve until maturity varied between types I and III in different years.

10. The population dynamics were compared and are discussed in the light of other data. The variable population characteristics suggested that Den Boer's “spreading of risk” theory applied to the T.terricola population.
Worker populations of Formica lugubris Zett. nests in Irish plantation woods
Authors: BREEN JOHN
Published: March 2008

Abstract. 1. Estimates of worker populations of Formica lugubris Zett. nests in Irish plantation woods were obtained using capture—mark—recapture methods. Forager numbers were estimated by paint‐marking individuals on the foraging routes and ‘recapturing’ by traffic counts. Colony‐size was estimated using Stradling's (1970) 32P‐radiolabelling technique. Worker brood was estimated by excavation and direct count.

2. Forager numbers ranged from 6906 to 64 686 (eleven nests), colony‐size ranged from 9797 to 71 052 (five nests) and worker brood ranged from 9809 to 16 269 (four nests).

3. Forager number was highly correlated with the average traffic on individual routes and the nest forager populations declined rapidly in >30‐year‐old nests.
A line transect density index for wolf spiders (Pardosa spp.), and a note on the applicability of catch per unit effort methods to entomological studies
Authors: GREENSTONE MATTHEW H.
Published: March 2008

Abstract. 1. A line transect density index for small wolf spiders is described and shown by means of regression analysis to provide adequate accuracy and excellent reproducibility.

2. A review of the literature discloses numerous regression and replication studies of other catch per unit effort methods possessing equal precision and reliability.

3. Such methods, when used judiciously, can provide accuracy and reproducibility as good as those obtainable using the statistical methods now in wider use, and deserve serious consideration in many kinds of sampling situations.
Analysis of a host—parasite (Ceratitis‐Muscidifurax) relationship under laboratory conditions*
Authors: PODOLER H. , MENDEL Z.
Published: March 2008

Abstract. 1. The relationship between the parasite Muscidifurax raptor and its host, puparia of the Mediterranean fruit fly Ceratitis capitata was studied. Emphasis was placed on quantitative descriptions of parasite responses and behaviour.

2. Female parasites ‘paralyse’ the host prior to oviposition. This treatment is not essential for larval development but crucial when oviposition took place in fully developed pupae. When having the choice females preferred to parasitize older hosts.

3. Parasite efficiency was affected by temperature, and reached its greatest value at 28°C. Increasing parasite density reduced the searching efficiency when it exceeded a certain level. A stronger effect of similar type was obtained by increasing the number of males per female. Apart from affecting efficiency of search, increasing parasite density caused an increasing proportion of males in the progeny.

4. Parasites responded to host density by weak functional response followed by reduction in efficiency of search due to egg limitation.

5. The parasites responded to host distribution by aggregating on high host densities. Such aggregation is antagonistic to the tendency to disperse due to mutual interference.
Population ecology and change in range of the white admiral butterfly Ladoga Camilla L. in England
Authors: POLLARD E.
Published: March 2008

Abstract. 1. Ladoga Camilla L. underwent a striking expansion of range in the 1930s and early 1940s. The study was undertaken to investigate the reasons for this expansion.

2. A life table study in Monks Wood, Cambridgeshire, analysed by the k factor method, showed the key factor to be late larval and pupal mortality. The mortality of these stages, believed to be due to bird predation, was dependent on the duration of the stages. At low temperatures the stages were prolonged and mortality high. Due to this relationship mean June temperature was closely correlated with adult numbers.

3. Information from entomological journals from 1900 to 1977 was used to identify the timing of the expansion of range as precisely as possible. A good agreement was found between June temperatures over the period and the timing of the expansion.

4. Although weather conditions determine year‐to‐year fluctuations it is likely that long‐term habitat changes also have an impact on L.camilla populations. The abandonment of traditional coppice management of woodland is considered to have increased the area of woodland suitable for the species and so played a role in its expansion.
The biology and host searching behaviour of a Cynipoid parasite of aphidophagous syrphid larvae
Authors: ROTHERAY GRAHAM E.
Published: March 2008

Abstract. 1. Callaspidia defonscolombei was found to be a common, solitary, thelytokous parasitoid of aphidophagous syrphid larvae. In 1977 it was bivoltine with adults being most numerous in early August and late September. It is probably polyphagous.

2. An analysis of host searching behaviour suggests that females respond to an aphid odour bringing them to the region of an aphid colony.

3. Syrphid hosts are located within the aphid colony by response to a contact chemical. There is a host size preference, only larger second and third instar larvae being attacked.

4. Females inject a venom, which temporarily paralyses host larvae, and place the egg inside a cerebral ganglion.
Cold tolerance of micro‐arthropods from Alaskan taiga
Authors: BLOCK WILLIAM
Published: March 2008

Abstract. Mean supercooling points for a variety of soil and litter arthropods including mites, springtails, a heteropteran and immature spiders from a central Alaskan taiga site ranged from ‐6.3 to ‐28.5°C during autumn. Variation in supercooling ability of five species of cryptostigmatid mites occurred throughout the year with increased cold tolerance in autumn and early winter concomitant with the temperature pattern of the habitat. No correlation between the level of supercooling and water content of the mites was evident. Changes in the frequency distribution of individual supercooling points occurred in autumn, winter, spring and summer samples which were species specific. All arthropods tested were susceptible to freezing, and the mites utilize supercooling to avoid freezing.
The life cycle and growth of Sialis lutaria L. (Megaloptera) in a drainage channel under different methods of plant management
Authors: BROOKER M. P.
Published: March 2008

Abstract. 1. The life cycle of Sialis lutaria in two experimental reaches, one treated with the herbicides dalapon and 2,4‐D (Chemical) and the other subjected to a conventional method of plant control (Hand), of a drainage channel in Essex took about 2 years.

2. A maximum density of 815 m‐2 was recorded and the density of each year class in both reaches generally decreased exponentially with age.

3. At certain times of the year the mean individual weight of each year class increased exponentially with age. Annual production was estimated to be 985 (Hand) and 1171 (Chemical) mg dry weight m‐2, with ratios of annual production to mean standing crop (P: b̄) of 1.6 and 1.8 respectively.

4. There was no evidence that the use of herbicides had any discernible effect on the mortality, growth or production of S.lutaria.
Diapause in twenty‐three populations of Plodia interpunctella (Hübner) (Lep., Pyralidae) from different parts of the world
Authors: BELL C. H. , BOWLEY C. R. , COGAN P. M. , SHARMA S.
Published: March 2008

Abstract. 1. The incidence of diapause in twenty‐three populations of Plodia interpunctella from fifteen countries representing all continents of the world was examined. The origins of populations varied from 52°N to 35°S and included two from equatorial regions.

2. Diapause occurred in all population samples at 20°C in short photoperiods (LD 11:13) and in continuous light, although the proportion of larvae doing so was less than 25% in samples from the equatorial belt.

3. The critical photoperiod was less than 13 h in five samples, all from the tropics, or southern hemisphere. The remaining samples, including three from the southern hemisphere, had critical photoperiods of 13 h or more.

4. Diapause was completely avoided by a 15 h photoperiod at 20°C in thirteen of the twenty‐three samples, including all but one of those from the southern hemisphere.

5. At 25°C larvae entered diapause in short photoperiods (LD 9:15) in about half of the samples tested in both hemispheres, but the proportion per sample was always less than a third.
Nest‐site selection in the great golden digger wasp, Sphex ichneumoneus L. (Sphecidae)
Authors: BROCKMANN H. JANE
Published: March 2008

Abstract. 1. Sphex ichneumoneus are solitary, ground‐nesting wasps with apparently broad nesting requirements.

2. Nest‐site selecting behaviour involves four levels of decisions. First, the wasps are not active unless temperatures are high and they are less active during cloudy weather. Second, at the beginning of a nesting sequence they generally fly to the site from which they emerged, but occasionally they fly to other flat, vegetation‐free areas. Third, after landing, they engage in a predigging search of the area, walking around, looking into and briefly digging in the nests of other wasps. In this way they apparently compare and choose to begin digging in the warmest areas available which are not too close to other nests. Fourth, if the soil is too soft and collapses or if it is too hard‐packed, the wasp resumes the predigging search. The preference for digging within a range of compactness means that they generally choose sandy loam.

3. Theory would suggest that the wasps may spend an optimal amount of time in the predigging search behaviour and that frequency‐dependent selection may be an important factor in the choice of nesting sites.

4. By choosing nesting sites according to these rules, the wasps are ensuring that their offspring develop in the warmest and best‐drained soils available.
Colour‐pattern variation in relation to habitat in the grasshopper Chorthippus brunneus (Thunberg)
Authors: GILL PETER D.
Published: March 2008

Abstract. 1. Chorthippus brunneus were collected from twenty‐two different sites in Nottinghamshire, Derbyshire and Essex.

2. Discrete characters of the head, pronotum and forewings and hind femora were scored. The results were compared with the types of habitat from which the grasshoppers were collected.

3. Associations between striped and mottle‐winged varieties were found.

4. The relationships between colour and habitat were examined.
Sex ratio, pupal parasitism, and predation in two declining populations of the bagworm, Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae)
Authors: HORN DAVID J. , SHEPPARD ROGER F.
Published: March 2008

Abstract. 1. Two populations of bagworms were censused in Ohio for 6 and 5 years respectively, to determine the influence of major pupal mortality factors. Bagworm densities declined from 2.3 bags per 30 cm of terminal branch to zero.

2. No single key mortality factor was identified in population trends. Parasitic Hymenoptera were common but variable in effect. Avian predation may have been important in reducing one population, while the other was exterminated after a drastic change in sex ratio to favour males.
Effects of prey‐size and predator‐instar on the predation of Daphnia by Notonecta
Authors: McARDLE B. H. , LAWTON J. H.
Published: March 2008

Abstract. 1. Attack rates and handling times are measured by a series of separate functional response experiments for each instar of Notonecta glauca attacking four size classes of Daphnia magna as prey. The resulting attack rate and handling time surfaces are complex, with maximum attack rates for small predators attacking small prey, and large predators attacking large prey. Adult Notonecta have lower attack rates than the two previous juvenile instars (4 and 5).

2. The literature on attack rates and handling times in other predator—prey interactions that involve a series of different predator and prey size or age classes is reviewed in the context of the Notonecta‐Daphnia results. The data suggest that small predator instars will usually compete with large instars for food, unless there is spatial or temporal separation between them.

3. Complex attack rate and handling time surfaces are to be expected wherever a wide range of prey and predator sizes is involved.

4. Size related changes in attack rates and handling times can introduce very complex dynamics into predator‐prey interactions.
Characteristics and distribution of opposition sites of the grasshopper Zonocerus variegatus (L.)
Authors: PAGE W. W. , McCAFFERY A. R.
Published: March 2008

Abstract. 1. The dry‐season population of Zonocerus in southern Nigeria oviposits in dense aggregations under single or clumped woody plants or on the edge of tall continuous stands of vegetation. No egg pods were found oviposited singly.

2. The vegetation under which oviposition occurs is the most common available at the time of the year. There seems to be no selection of particular species of plants so long as they provide good low shade.

3. Oviposition can take place in a wide range of gravelly soils.

4. Topography is not important as long as the oviposition site is on high ground away from damp areas subject to flooding.

5. There was a mean of 618 pods per oviposition site from forty‐one sites which were dug up, and there was a significant correlation between the area of a site and the number of pods.

6. There was a marked tendency for oviposition sites to be found close to cassava. At two localities of approximately 20 ha each 90% of the sites were found within 30 m of cassava.

7. It is suggested that permanent shade is the most important factor in the selection of a site and this is probably related to the survival of the eggs during their 6–7 months development.
Development of Habrolepis rouxi Compere (Hymenoptera: Encyrtidae) in two armoured scale hosts (Homoptera: Diaspididae) and parasite egg encapsulation by California red scale
Authors: BLUMBERG DANIEL , DeBACH PAUL
Published: March 2008

Abstract. 1. California red scale Aonidiella aurantii (Maskell) and oleander scale Aspidiotus nerii Bouché (Homoptera: Diaspididae) are not completely suitable for the development of the encyrtid endoparasite Habrolepis rouxi Compere.

2. Mortality of parasite immatures in California red scale is caused mainly by egg encapsulation. Although oleander scale is unable to encapsulate H. rouxi, it is nutritionally unfavourable for the parasite's development.

3. Some immunity to the parasite is conferred to the oleander scale by the particular host plant used.

4. The parasite's rate of development is not influenced by the host species studied.

5. The mortality of parasite immatures in California red scale is lower than in oleander scale. The former host also is more acceptable and preferred by the parasite for ovipositon. These characteristics of the California red scale render it more suitable than oleander scale as host for H. rouxi.

6. Studies on the encapsulation of H. rouxi eggs by the California red scale indicate that (i) encapsulation does not prevent third instar host larvae from maturing and producing progeny; (ii) neither rearing temperature nor host age affect encapsulation frequency.
Abundance and reproductive strategy of the dung beetle Aphodius rufipes (L.) (Scarabaeidae)
Authors: HOLTER P.
Published: March 2008

Abstract. 1. Adult A.rufipes invade fresh dung pats (mainly in August) and stay for a few days in each pat to feed and oviposit; maximum abundances: 0–100 beetles per cattle dung pat. Larval growth is completed within 40–55 days.

2. The dispersion of beetles is contagious or seemingly random. In sunny weather, with rapid crust formation on the dung, pats deposited in the afternoon are invaded by more beetles than those deposited in the morning.

3. In the field, the total number of eggs per pat is significantly less variable than the number of adult beetles; this might indicate a density‐dependent, regulatory, rate of oviposition. The subsequent larval mortality is probably density‐independent.

4. Experiments confirmed that the number of eggs laid per female‐day in the pats was density‐dependent.

5. The non‐opportunistic reproductive strategy of A.rufipes may have evolved as an adaptation to life in dung pats: at excessive population densities pats might disappear before completion of larval growth.

6. Finally, A.rufipes in dung pats is compared with blowflies breeding in carrion.
The responses of carrot fly larvae, Psila rosae, to components of their physical enrivonment
Authors: JONES O. T.
Published: March 2008

Abstract. 1. The responses of third instar Psila rosae (F.) larvae to light, temperature, humidity and soil moisture were investigated in the laboratory.

2. Larvae were photonegative and preferred a temperature of about 15°C. Temperatures between 30 and 40°C adversely affected movement and over 40° C were lethal.

3. In choice chambers, larvae preferred humidities of 70–100% r.h. and larvae in sand avoided dry conditions (2.5% field capacity). The latter response became more marked as larvae approached the pre‐pupal stage when moistures of 40% field capacity and lower were avoided.

4. Most larvae were found at a depth of 8 cm in sand of uniform moisture content and temperature, but variation in moisture content could alter this preference.

5. In August, most larval damage in the field occurred near the tip of the carrot tap root but was more evenly distributed over the roots in November. It is uncertain whether this was due to soil near the surface being drier in August or whether it was caused by behavioural differences between the two generations of carrot fly larvae.

6. During the summer of 1975, low soil moisture levels resulted in the total absence of larval mines on the carrot roots even though pupae were found at depths of 20–30 cm in the soil. Temperature had no effect on the distribution of mines on carrot roots except at the top 2 cm of the soil profile.
Effects of constant and variable temperature extremes on sex ratio and progeny production by Aphytis melinus and A.lingnanensis (Hymenoptera: Aphelinidae)
Authors: KFIR RAMI , LUCK ROBERT F.
Published: March 2008

Abstract. 1. Aphytis melinus DeBach and A.lingnanensis Compere were exposed to temperature extremes during development, mating, preoviposition, and opposition to assess the effect of these exposures on the progeny per female and F1 sex ratio.

2. Both species showed a significant reduction in the expected proportion of F1 females when the male parent was exposed to 32°C during its development.

3. The proportion of females was further reduced when mating and/or oviposition occurred at 32°C and these effects on sex ratio appeared cumulative.

4. Preovipositional exposure of the females of both species to 38°C, 2°C or ‐2°C for 1 5, 4 or 7 h in most cases significantly reduced the expected proportion of females.

5. In general our results showed that the sex ratios of A.melinus was less severely affected by these exposures than were those of A.lingnanensis.

6. It is suggested that this difference may be one factor explaining the ability of A.melinus to exclude A.lingnanensis from the climatically more extreme areas of southern California.
A study of fungus flies (Dipteral Mycetophilidae) in beech woodland
Authors: RUSSELL‐SMITH A.
Published: March 2008

Abstract. 1. A study was made of larval and adult Mycetophilidae in coppiced beech woodland in southern England. Adult mycetophilids were trapped throughout 1968 using sticky traps at ground level. Larvae inhabiting terrestrial fungi were collected from all sporophores from a defined area of the woodland floor between August and October 1968.

2. Larval mycetophilids were extracted from only 12.6% of all sporophores collected and from fifteen of thirty‐eight species of fungi present. Some species of fungi were never inhabited by larval mycetophilids while others appeared to be highly attractive to them. Since it was not possible to identify the larvae beyond the level of tribe it was impossible to ascertain host preferences for different species. Peak numbers of larvae occurred at the beginning of September and the beginning of October.

3. Adult mycetophilids had two peaks of activity, the first in March and April when the dominant species were Boletina gripha and Phronia basalis and the second in autumn when species of the genus Mycetophila were dominant. Phronia basalis is a species whose larvae inhabit dead wood and the abundance of this species (40% of all adults) probably reflects the amount of rotting wood in this type of habitat. The autumn peak of adult activity was due to species known to inhabit agaric sporophores and came about 1 month after the peak of larval numbers in fungi.

4. The adult fauna was rich with 107 species representing about a quarter of the known British fauna. However, only twelve species were trapped in sufficient numbers to allow deductions concerning seasonal activity.

5. The results were discussed with respect to the problems of assessing populations of insects inhabiting fungal sporophores and to the previous work on this neglected group.
Sex ratio regulation in Coccygomimus turionella Linnaeus (Hymenoptera: Ichneumonidae) and its ecological implications
Authors: SANDLAN KENNETH
Published: March 2008

Abstract. 1. Sex regulation and its relevance to the ecology of a k‐selected pupal parasitoid was investigated in Coccygomimus turionellae.

2. The ratio varied with host size, females predominating in large hosts.

3. Egg transfer experiments and comparative mortality rates among the progeny of virgin and inseminated females demonstrated that the phenomenon was due to parental behaviour.

4. The study of the mechanism confirmed Aubert's hypothesis of host size estimation with the addition that the host had to be exposed from the poles and had to contain the proper host kairomones.

5. Host size was highly correlated to parasitoid fecundity via influences on size and longevity but not the number of ovarioles per female or daily egg production.

6. Host encounters are more limiting than egg production and host size had no effect on host acceptance.

7. Sex regulation allows a maximal host encounter rate at the same time that it maximizes the reproductive potential of female progeny.

8. Low host density increased the production of female progeny resulting in more offspring searching for the limited resource. Concealed hosts and a high host density resulted in a shift towards a Fisher 1:1 sex ratio.
Environmental control of pupal colour in swallowtail butterflies (Lepidoptera: Papilioninae): Battus philenor (L.) and Papilio polyxenes Fabr.
Authors: HAZEL WADE N. , WEST DAVID A.
Published: March 2008

Abstract. 1. Some swallowtail butterflies produce both green and brown pupae. The phenotypes result from the joint action of genotype and environment and usually make the pupae cryptic in their habitats.

2. The major environmental cues influencing pupal colour in two swallowtail species were determined to be textural and optical.

3. Differences in the usage of these kinds of cues in the two species are thought to have evolved because of major differences in the pupation habitats. P.polyxenes, which usually pupates on slender stems amidst vegetation, responds more strongly to optical cues. B.philenor, which usually pupates on exposed surfaces of tree trunks and cliffs, responds more strongly to textural cues.

4. Differences in the overall tendency to produce brown pupae (‘sensitivity’: Hazel, 1977) are thought to be related to the frequency of brown pupation sites utilized by these two species: high average sensitivity in philenor, which often uses brown sites, and lower average sensitivity in polyxenes, which often uses green sites.
A preliminary study of dispersal and survival of Anopheles culicifacies in relation to the possibility of inhibiting the spread of insecticide resistance
Authors: CURTIS C. F. , RAWLINGS P.
Published: March 2008

Abstract.

Blood‐fed Anopheles culicifacies were collected in a cow‐baited hut, marked with fluorescent powder and released in the same hut. Captured mosquitoes were checked for the presence of marks from the previous day's releases. These checks were carried out on those captured in the release hut and in three similar huts at distances of up to 500 m away.

By dividing the percentage found to be marked in the outlying huts by the percentage marked found on the same day in the release hut, estimates were made of the extent of ‘overlap’ between the populations sampled by the different huts.

Evidence from the rate of build‐up in the percentage marked, from the daily loss rate when a ‘pulse’ of a different colour mark was used, and from the parity rate, gave information on mosquito survival and the interval between marking and recapture. This was notably high in view of earlier field work on the same species in India and of the fact that all houses on the site of the present experiment had been sprayed with malathion.
A population study in Jamaica on adult Sceliphron assimile (Dahlbom) (Hymenoptera: Sphecidae)
Authors: FREEMAN B. E.
Published: March 2008

Abstract.

A mark–recapture study on the sphecid wasp Sceliphron assimile (Dahlbohm), analysed by Jolly's stochastic method (1965), was made from 3 December 1974 to 22 February 1975 at Green Bay, St Catherine, Jamaica.

Population levels in an 18.2 ha study area fluctuated about a mean of 281 for males, 259 for total females and 87 for reproducing females, while the probable carrying‐capacity for these reproductives was about 104.

Mean estimated daily survival rates were 0.903 for males, 0.924 for total females and 0.945 for reproducing females. For the first two categories these rates decreased (p < 0.02) during the study, probably reflecting increasing emigration. Reproducing females probably do not emigrate and their survival did not significantly decrease.

Minimum age was linearly related to wing wear (r=+0.69, P < 0.001) and the latter associated with the progressive maturation and ageing of the ovaries. All surviving females become parous by middle age.

The mean rate of fecundity in the field was dependent on female age and was reduced during prolonged drought. Curves of total achieved fecundity appropriate to realistic survival rates give 4.2–16.8 eggs/female. The Jamaican mean was 9.6 ± 2.3 and that for Green Bay 8.6.

The proportion of females in the Green Bay population was 0.48 ± 0.03 while 0.55 was expected at emergence.

A cyclic budget is used to estimate immigration and emigration, and these were important causes of population change.

For Jamaica, only an estimated 28% of females survived to nest.
Interpopulation quality in gypsy moths with implications for success of two pupal parasitoids: Brachymeria intermedia (Nees) and Coccygomimus turionellae (L.)*
Authors: GREENBLATT J. A. , BARBOSA P.
Published: March 2008

Abstract.

Gypsy moth egg masses were collected from innocuous, release and outbreak populations and reared in the laboratory on synthetic diet under identical conditions.

Outbreak population gypsy moths hatched sooner, were smaller and less fecund than innocuous or release gypsy moths, but had a higher concentration of total carbohydrates in their haemolymph.

Pupae from each population source were submitted to parasitization by two pupal parasitoids. Emerging B.intermedia, an established parasitoid of the gypsy moth associated with outbreak populations, were largest on outbreak source gypsy moths. C. turionellae, not a usual parasitoid of the gypsy moth, were largest when emerging from innocuous or release population gypsy moths. Implications for population dynamics of the gypsy moth are discussed.
The effects of prey density on survival and growth of damselfly larvae
Authors: LAWTON J. H. , THOMPSON B. , THOMPSON D. J.
Published: March 2008

Abstract.

Instar 10, 11 and 12 Ischnura larvae were maintained throughout the instar on a constant food supply (Daphnia magna of a standard size).

A very narrow range of prey availability separated cohorts in which all the larvae successfully moulted to the next instar, from those in which all the larvae died (less than one Daphnia per day in the case of instar 10).

Larvae were able to survive long periods without food at 16°C.

Prey availability had a marked effect on development rates, which continued to increase at prey densities well in excess of 100% survival by the larvae.

The data on Ischnura survival and development rates are compared with previously published general models of these two components of the predators' rate of increase.

We conclude that starvation is very unlikely to be a significant cause of mortality in the field for Ischnura (or indeed most other Odonata larvae), but that prey availability undoubtedly influences development rates. Natural selection should therefore favour larvae that forage optimally to minimize development times.
The effect of nectar abundance on foraging patterns of bumble bees
Authors: MORSE DOUGLASS H.
Published: March 2008

Abstract.

Bumble bees (Bombus spp.) fed more on previously screened, nectar‐rich plots of cow vetch (Vicia cracca) and white clover (Trifolium repens), and remained longer on inflorescences there, than on continually‐exploited plots of these flowers. No significant differences between previously screened and continually available plots occurred in the number of individuals visiting these two areas, the number of inflorescences per visit, the number of florets visited per inflorescence, and the percentage of inflorescences rejected.

Individual bees were analysed in greater detail. They visited more inflorescences and spent longer times on cow vetch in the previously‐screened plots, whether moving from previously‐screened to continually available areas, or vice versa. On white clover the same pattern held for bees moving from previously screened to continually available plots, but not for those moving from continually available to previously‐screened areas.
Quantitative studies on the eggs of Simulium (Simulium) ornatum Meigen and Simulium (Wilhelmia) equinum L. in a chalk stream in southern England
Authors: WELTON J. S. , BASS J. A. B.
Published: March 2008

Abstract.

The egg masses of Simulium ornatum, S.equinum and S.vernum are described and information is given on numbers of eggs per egg mass and the size and number of batches laid by individual females.

The oviposition sites were studied in relation to water velocity, wind speed and direction.

The incubation periods at different river temperatures and the effects of desiccation on percentage hatch and incubation times were investigated.

The numbers of eggs laid were assessed for the winter generations of S. ornatum and S.equinum. The relevance of these to the overall production estimates is discussed
Insect–fern interactions: macrolepidopteran utilization and species–area association
Authors: AUERBACH MICHAEL J. , HENDRIX STEPHEN D.
Published: March 2008

Abstract.

The generalization that ferns are under‐utilized by phytophagous insects in comparison to angiosperms may be invalid because of biases involving plant growth form, plant range, and unequal sampling efforts.

Comparison of nineteen fern species with 652 herb species, the angjosperm growth form most similar to the ferns, indicates no significant difference in the mean number of supported macrolepidopteran species. When the herbs are subdivided into annuals, biennials and perennials, only the annual herbs are significantly different than the ferns.

Comparisons of the occurrence distributions for ferns and the herb categories also demonstrate that only the annual herbs support more macrolepidopteran species than the ferns. The same results are obtained when random assemblages of herbs are created that are the same size as the fern assemblage.

Both the occurrence distributions and the species–area relationship for the ferns indicate that host records for insects feeding on ferns may be grossly incomplete.

The similarity of exploitation of ferns and perennial herbs by the Macro‐lepidoptera suggests that other foliage feeding insects may also use ferns at levels equivalent to angiosperms.
The distribution and abundance of the coccid leery a seychellarum Westw. on Aldabra atoll
Authors: HILL M. G. , NEWBERY D. McC.
Published: March 2008

Abstract. Icerya seychellarum, a polyphagous phloem feeding coccid, was discovered on Aldabra atoll in 1968. It was not recorded by early expeditions to the atoll, and is probably a recent introduction. Its infestation rose to a peak density around 1975, and thereafter declined, as revealed by a comparison of fifty‐one woody taxa common to three surveys. In 1975, twenty‐one taxa were ‘heavily’ infested and twenty‐one ‘lightly’/‘moderately’ infested. By the end of 1978, no taxa remained ‘heavily’ infested and thirty‐seven were ‘lightly’/‘moderately’ infested. The state of vegetation showed negligible change between the 1976/77 and 1978 surveys, refuting an earlier prediction that it would be substantially modified by the Icerya infestation.

The subsequent decline in infestation cannot here be attributed to the development of natural enemies. Possible reasons, which are discussed, include changes in the quality of the coccid or its host.
Nerium oleander as an alternative host plant for south Florida milkweed bugs, Oncopeltus fasciatus
Authors: KLAUSNER EDWARD , MILLER ELIZABETH RUTH , DINGLE HUGH
Published: March 2008

Abstract.

Life history data were gathered for south Florida Oncopeltus fasciatus reared from eggs on Nerium oleander seeds and milkweed seeds in the laboratory.

Milkweed seeds were found to be a superior food source since O.fasciatus grew faster, laid more clutches, and has a higher total fecundity on milkweed seeds.

Fruiting N.oleander was found to be a better food source than nonfruiting milkweeds in a summer field study in south Florida since no nymphs survived to the adult stage on nonfruiting milkweeds but some did on N.oleander.

O.fasciatus adults and nymphs are abundant on N.oleander in the summer in south Florida when N.oleander is fruiting; no O.fasciatus nymphs are found in the summer on the milkweeds which are not fruiting.

O.fasciatus leave N.oleander in the autumn when milkweeds start to fruit and can then be found on fruiting milkweeds.
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.
Comparative timing of brood development between multiple‐ and single‐foundress colonies of the paper wasp, Polistes metricus
Authors: GAMBOA GEORGE J.
Published: March 2008

Abstract. Multiple‐foundress colonies of Polistes metricus Say produce their first workers earlier than single‐foundress colonies. This is probably an advantage in reducing predation and usurpation by conspecifics and may partially explain the advantage to certain foundresses in joining other foundresses, likely their sisters, rather than establishing their own nests alone. There is no evidence that multiple foundresses work synergistically to accelerate brood development. Rather, foundresses normally join early‐established nests so that multiple‐foundress nests have an early start and thus produce workers early in the season.
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.