bluuebunny/crossref_metadata_2025 huggingface dataset:
Morph determination in Melittobia, a eulophid wasp
Authors: FREEMAN B. E. , ITTYEIPE K.
Published: March 2008

Abstract. 1. The Caribbean and Central American eulophid wasp, Melittobia sp. 1 (hawaiiensis complex), (Hymenoptera: Chalcidoidea), whose larvae are exophagous on the prepupae of solitary wasps and bees, has three adult female and two adult male morphs.

2. The males, which constituted only 5% of the progeny, had morphs with, and without, ocelli.

3. In the females, brachypterous, negatively phototactic ‘crawlers’ developed mainly at low densities (<8.9 eggs cm‐2), while above this density an increasing number and percentage of macropterous, positively phototactic ‘fliers’ were produced. Intermediate ‘jumpers’ were positively phototactic but could not fly.

4. In a typical progeny twenty to thirty ‘crawlers’, twenty to forty ‘jumpers' and up to 400 ‘fliers’ emerged in an overlapping sequence.

5. Experiments demonstrated that the proportions of the three morphs emerging were unrelated to the sequence in which the eggs were laid, to the species of the host and to the quality and absolute amount of food given, but related only to the density experienced by the young larvae.

6. We relate this trimorphism of dispersive female morphs to the three levels of ecological space (food item, patch and distribution of patches) postulated by Hassell & Southwood (1978) and suggest the general ecological conditions necessary for it to evolve.
The impact of forest cutting on the diversity of ground beetles (Coleoptera: Carabidae) in the southern Appalachians
Authors: LENSKI RICHARD E.
Published: March 2008

Abstract.1. Carabid beetles were sampled by means of pitfall traps on several clearcut areas and in adjacent forests.

2. A hierarchical analysis of diversity revealed a significant increase in the within‐genus component of species diversity after forest cutting.

3. This trend in intrageneric diversity was obscured, with respect to total species diversity, by a nonsignificant reduction in diversity at the generic level.

4. The increase in the within‐genus component of species diversity following forest cutting was consistent with the hypothesis that disturbance of a cornmunity can disrupt processes of competitive exclusion.
Leaf wilting alters a plant species ranking by the grasshopper Melanoplus differentialis
Authors: LEWIS A. C.
Published: March 2008

Abstract. 1. Field observations of the feeding behaviour of the polyphagous grasshopper Melanoplus differentialis suggest that plant quality can override plant species as a determinant of choice. When offered binary choices in laboratory tests between leaves of two host plant species, Helianthus annuus and Ambrosia trifida, in all combinations of wilted and turgid, grasshoppers prefer A. trifida in all test conditions, except when it is turgid and H.annuus is wilted. In this case, the preference switches to H.annuus

2. Preliminary evidence suggests that chemical factors are responsible for the alteration in preference.
Fitting split‐lines to ecological data
Authors: PERRY J. N.
Published: March 2008

Abstract.1. Ecological data from a variety of sources are often well fitted by a ‘split‐line’ relationship. The position of the peak and rates of growth to, and decline from this peak may be estimated. Examples are given for aphid data.

2. Invalid fits are explained and procedures given to choose the best valid fit. Examples are given for phorid data.

3.Techniques are described for fitting, simultaneously, different split‐lines to several sets of data, comparing parameters and finding the simplest adequate description of the data. Examples are given for earthworm data.
Influence of intertree distance on foraging behaviour of Rhagoletis pomonella in the field
Authors: ROITBERG BERNARD D. , PROKOPY RONALD J.
Published: March 2008

Abstract. 1. We tested a prediction from contemporary foraging theory that animals should decrease their allocation of energy to the searching of individual patches when interpatch travel costs decrease.

2. We used individual Rhagoletis pomonella Walsh (Diptera: Tephritidae) females foraging for oviposition sites (=Crataegus fruit) in a host tree which was surrounded by four other trees at varying distances.

3. We found that flies generally invested less search, measured as time spent searching a tree or number of leaves visited on a tree, when neighbouring trees were nearby than when farther away.

4. Under our test conditions, flies appeared to have difficulty locating neighbouring trees at a distance of more than 1.6 m.

5. Our study calls into question the interpretation of search effort by insects within resource patches in the absence of information on interpatch distances.
Prey attraction by luminous larvae of the fungus gnat Orfelia fultoni
Authors: SIVINSKI JOHN
Published: March 2008

Abstract. 1. Bioluminescence in predacious larvae of the fungus gnat Orfelia filtoni attracts potential prey.

2. Transparent traps placed over larvae caught more arthropods than opaque traps put over neighbouring conspecifics.

3. Small Diptera are particularly vulnerable to light lures, while apterous soil arthropods are seemingly unaffected.
Mimicry in North American checkerspot butterflies: Euphydryas phaeton and Chlosyne harrisii (Nymphalidae)
Authors: BOWERS M. DEANE
Published: March 2008

ABSTRACT.

An examination of the phenetics, ecology and distribution of Chlosyne harrisii suggested that it was a potential mimic of the unpalatable Euphydryas phaeton.

The wing undersurfaces of the adults are very similar and the larvae are virtually identical. The geographic range of both butterflies is the northeastern United States and both are inhabitants of wet meadow habitats where they may fly together. The life histories of both species are closely synchronized.

A series of feeding experiments using blue‐jays as predators showed first, that C.harrisii is palatable, and second, suggested that the birds could not distinguish between C.harrisii and E.phaeton on the basis of visual cues. Thus, Charrisii seems to be an effective Batesian mimic of E.phaeton.
Frequency‐dependent selection in the grazing behaviour of the desert locust Schistocerca gregaria
Authors: CHANDRA S. , WILLIAMS G.
Published: March 2008

ABSTRACT.

The locust displayed clear preferences in the ranking of five possible food plants: wheat > barley =Cypeius alternifolia > chives > lemon grass.

In two‐species stands of constant numerical density, the locust grazed selectively on the less‐favoured plant when it was relatively less abundant.

The behavioural mechanism of selective grazing was a change in the readiness to eat a plant as its relative frequency changed: i.e. the consumption/encounter ratio rose as relative density fell.

With the exception of Cyperus, which nutritionally is below chives, the preference ranking matched nutritional ranking as estimated by rearing‐success on single plant species.

It is suggested that such negative frequency‐dependent selection may be a common strategy for polyphagous herbivores as it permits a wide dietary intake without hazards from potentially toxic foods.
The hatching stimulus for eggs of Aedes punctor (Diptera: Culicidae)
Authors: FALLIS SIMON P. , SNOW KEITH R.
Published: March 2008

ABSTRACT.

Eggs of the British woodland mosquito, Aedes punctor (Kirby), were subjected to a variety of media in an attempt to determine the hatching stimulus.

It was found that continuous immersion in distilled water evoked almost no hatching (0.2%); intermittent removal from the water gave low hatching (8.9%).

Slow deoxygenation of the medium by either bacterial growth or the introduction of nitrogen produced the highest level of hatching (26.0–90.0%). Eggs of A.punctor were shown to hatch within a 4 h period of the oxygen concentration in the medium reaching zero.
Emergence of flies from overwintering populations of cabbage root fly pupae
Authors: FINCH S. , COLLIER ROSEMARY H.
Published: March 2008

ABSTRACT.

Once pupal diapause had been terminated, over‐wintering cabbage root fly (Delia radicum (L.)) pupae from Wellesbourne required a further 14 days at 20°C for most of the flies to emerge.

There were considerable variations in the rates of fly emergence from thirteen populations of cabbage root fly pupae collected between latitudes 50° 42′ and 54° 59′ in England and Wales. These thirteen populations could be grouped into early‐, intermediate‐ and late‐emerging types. In the early‐emerging type, flies emerged within 14 days at 20°C whereas in the late‐emerging type emergence was protracted and was completed only after 100 days at 20°C in one population from Halsall, Lancashire. In the intermediateemerging type, approximately two‐thirds of the flies emerged within 14 days at 20° C, the remainder taking considerably longer.

The intermediate‐emerging types could be just mixtures of the early‐ and late‐emerging types.

Subjecting pupae to diapause‐breaking temperatures (4°C) for up to 1 year failed to shorten the time to subsequent fly emergence in any of the populations.

Populations of early, intermediate‐ and late‐emerging fies could be selected from a parental population, heterogeneous with respect to emergence, within one generation.

The type of emergence that occurred in a locality was not correlated with latitude.

Any models developed for forecasting the most appropriate time to apply insecticide in a locality will have to include information about the emergence pattern of the fly population in that locality.
A field evaluation of the sexual competitiveness of sterile melon flies, Dacus (Zeugodacus) cucurbitae
Authors: IWAHASHI OSAMU , ITO YOSIAKI , SHIYOMI MASAE
Published: March 2008

ABSTRACT.

The sexual competitiveness of sterile melon fly males [Ducus (Zeugodacus) cucurbitue Coquillett] was estimated under field conditions.

The value of competitiveness was about 0.8 for flies in the fifth to tenth generation from the beginning of mass‐rearing, but decreased to about 0.2 in the eighteenth generation.

The sexual competitiveness estimated using laboratory data was near unity even in the final stage of our study.

It was concluded that the field evaluation of sexual competitiveness is essential to determine the quality of the insects reared for purposes of pest control.
The evolution of parental behaviour in Scarabaeinae (Coleoptera, Scarabaeidae): an experimental approach
Authors: KLEMPERER H. G.
Published: March 2008

ABSTRACT.

Dung beetle lifestyles are reviewed. Most Scarabaeinae lay their eggs in dung masses that are packed into underground chambers, but Coprini and Scarabaeini typically lay their eggs in free‐standing brood balls and it is in these tribes that parental care of the brood has evolved.

Brood balls are constructed by aggregating fragments of dung. This technique is derived from the method of gathering dung at the surface. Larvae developing in brood balls are better protected against dehydration and parasite attack. The repair technique of Scarabaeine larvae preadapts them to life in brood balls.

Parental care byCopris lunarisdepends on appropriate responses by the female to the brood, and it has the selective advantage of protecting the brood against parasites. Preadaptations for parental care in‘non‐brooding’Coprini are discussed.

Variations in the basicCoprisnesting behaviour are summarized. Similar variations can occur spontaneously inC.lunarisand can also be released by unusual circumstances.

C.lunarisfemales could in principle cooperate but certain factors have prevented this social evolution. The significance of the transient cooperation with the male beetle is discussed.
Temporal patterns of seed use and availability in a guild of desert ants
Authors: MEHLHOP PATRICIA , SCOTT NORMAN J.
Published: March 2008

ABSTRACT.

Temporal patterns of seed use were studied from late winter to autumn in three species of seed‐harvesting ants in the Sonoran Desert. Measures of effective foraging activity, dietary niche breadth and dietary niche overlaps were obtained each month and were tested for correlation with estimates of the available seed resource.

Seeds were the only numerically important type of food in the diets of all species.

The ants partitioned the resource according to both seed species and seed size, although there was considerable overlap.

Pheidole xerophila had the smallest forager body size and is a specialist on small seeds because it harvested them in greater proportion than their rank in the soils and expanded its diet to larger seeds only when the abundance of small seeds declined.

When the abundance of the small seeds of Bouteloua barbata decreased, the middle‐sized ant, Veromessor pergandei, showed a decrease in foraging activity, increase in niche breadth, and a decrease in overlap with P.xerophila.

Seed size preferences of V.pergandei did not vary seasonally, except that during the month of highest seed abundance, V.pergandei showed no size preference.

Pogonomyrmex rugosus was the largest ant; it preferred larger seeds and was inactive when small seeds were most abundant. Seasonal foraging activity and niche parameters were random in relation to seed abundance.

We suggest that nocturnal foraging by P.rugosus during the summer months was a response to interference with diurnal foraging by either predation frorn horned lizards or competition from V.pergandei.

Seasonal abundance of small seeds explains most of the seasonal foraging patterns of P.xerophila and V.pergandei. The summertime abundance of larger seeds during years of adequate precipitation may account for the seasonal activity patterns of P.rugosus.
Phenology and life history of Belgica antarctica, an Antarctic midge (Diptera: Chironomidae)
Authors: SUGG PATRICK , EDWARDS JOHN S. , BAUST JOHN
Published: March 2008

ABSTRACT.

An account of the life‐history with emphasis on phenology and number of instars is presented for Belgica antarctica Jacobs, the southernmost holometabolous insect.

Contrary to earlier reports, Belgica has four instars, in common with most other chironomids. Mean head capsule lengths varied between different populations but no overlap was found between discrete size classes of successive instars.

Belgica overwinters in all four instars.

Relative frequency of different instars from samples taken through the season indicates that a 2‐year life‐span is the commonest pattern.

Emergence of adults is relatively synchronous. Belgica exhibits protandry, which may be established at the time of pupation.
Distribution of the eggs of Aedes punctor (Diptera: Culicidae)
Authors: FALLIS SIMON P. , SNOW KEITH R.
Published: March 2008

ABSTRACT.

Eggs of the mosquito Aedes punctor Kirby were found to be aggregated in a horizontal band within woodland depressions.

The height of the peak of egg density above the lowest point in the depression varied from 24 to 39 cm in six transect studies.

One depression, 2 m in diameter, was analysed in detail and found to contain a total of 9231 eggs with a maximum density of 944 eggs in a 250 cmz area.
Thermal niche partitioning in the grasshoppers Arphia conspersa and Trimerotropis suffusa from a montane habitat in central Colorado
Authors: GILLIS J. E. , POSSAI KURT W.
Published: March 2008

ABSTRACT.

Two species of grasshoppers, Arphia conspersa and Trimerotropis suffusa, coexist in a montane habitat in central Colorado.

Field‐recordings of body temperature revealed that A.conspersa has a significantly lower mean body temperature (Tb), sexual display temperature (Td) and minimum flying temperature (MFT) than T.suffusa.

A test of the maximum voluntarily tolerated temperature (MVT) showed that T.suffusa has a higher MVT than A.conspersa.

Thermal niche breadth, as indexed by the difference between MVT and MFT and the range of environmental temperatures over which each species is active, is broader in the eurythermic A.conspersa than in the stenothermic T. suffusa.

Thermoregulatory ability, as evaluated by regression analysis of Tb on Ta, was shown to be better in T.suffusa than in A.conspersa and in displaying grasshoppers of both species than in non‐displaying ones. The significance of these findings with respect to a cost‐benefit model of behavioural thermoregulation in ectotherms is discussed.

Based on these data and observations it was concluded that A.conspersa and T.suffusa occupy different thermal niches and that thermal considerations may be importantly related to habitat preference, daily activity patterns, and consequent ecological separation.
Fugitive species and priority during colonization in carrion‐breeding Diptera communities
Authors: KNEIDEL KENNETH A.
Published: March 2008

ABSTRACT.

Experiments were conducted to test for the presence of fugitive species and priority effects among the Diptera species that breed in dead slug carcasses (Limax maximus L.).

Slug carcasses exposed for only 1 day produced a community that was very similar to that bred from carcasses exposed until fully decomposed. This suggests that competitive ability and dispersal ability are positively correlated in this system.

The colonization of flies was manipulated by transferring larvae of the phorid, Megaselia scalaris Loew, to carcasses before and after they were exposed in the field. A‘priority effect’was demonstrated in that M.scalaris survived better and had a stronger impact on other species when it was the first species to colonize slug carcasses.
Contrasting foraging related behaviours in two sympatric wasps (Vespula maculifrons and V. germanica)
Authors: PARRISH M. D. , FOWLER H. G.
Published: March 2008

ABSTRACT.

Using pinned freshly killed wasps (yellowjackets) to simulate feeding animals, it was found that V. germanica was socially facilitated, and concentrated its foraging activity on those feeders with the most pinned wasps (twenty). V. maculifrons foragers responded inversely, preferentially foraging at feeders with few or no pinned wasps.

Using hand‐painted drawing pins (thumb tacks) as wasp models, similar results were found, indicating that visual, rather than olfactory, cues were responsible for the observed distribution.

Vespula maculifrons and V. germanica exhibit aggression while foraging at honey‐baited feeders. Both species attack conspecifics at frequencies lower than would be expected under random encounter.
Seasonal colour changes, sexual maturation and oviposition in Psylla peregrina (Homoptera: Psylloidea)
Authors: SUTTON ROBIN D.
Published: March 2008

ABSTRACT.

Colour change is shown to be related to the timing of sexual maturation of P.peregrina Förster. Males become sexually mature and attain their autumnal coloration about 3 weeks before females.

Upon maturation males migrate down branches into the inner crowns of hawthorn trees. Females show a similar movement as they mature later in the season.

Seasonal colour changes may serve cryptic functions and are appropriate to the different environments in which adults are found during the season.

The distribution of overwintering eggs reflects the post maturation distribution of adult psyllids, with eggs being concentrated on old wood towards the base of hawthorn branches.
Selection of plant parts by Depressaria multifidae (Lep., Oecophoridae) on its seasonally‐restricted hostplant, Lomatium grayi (Umbelliferae)
Authors: THOMPSON JOHN N.
Published: March 2008

ABSTRACT.

Depressaria multifidae Clarke feeds on a broader variety of Umbelliferae plant parts than other Depressaria species.

Early instar larvae feed in the sheaths surrounding floral buds and leaves. Later instar larvae feed in the sheaths and floral stems and on flowers and leaves.

Floral stems bored by larvae had significantly larger basal stem diameters than floral stems that were not bored. Smaller stems usually have umbels with only male flowers, and wither after flowering, too soon for larvae to complete development. In contrast, larger stems often have umbels with some hermaphroditic flowers, which remain green and erect long enough for larvae to complete development. Hence, selection may favour larvae that bore only in relatively large stems.

In the laboratory, larvae fed sheaths with enclosed floral buds, flowers, or leaves all pupated at the same weight, but larvae fed floral stems pupated at a significantly lower weight. Larval and pupal development time was the same on all plant parts.

In the field, larvae restricted to a single umbel throughout development pupated at the same weight as those restricted to a single leaf.

Unlike in other Depressaria species, nitrogen levels only partly correspond to the pattern of use of plant parts in D.multifidae. Nitrogen values varied as follows: floral buds > immature leaves ≥ flowers > floral stalks > sheaths excluding floral buds or leaves.

The broad variety of plant parts used by D.multifidae may result partly from the problem of feeding on a small, seasonally restricted hostplant; the greater use of sheaths and floral stems than in other Depressaria species may result from selection for safety from parasites or predators.

The results for D.multifidae indicate that the way in which an insect feeds on a plant species can vary broadly even at a single site.
Annual respiration and production estimates for collembolan and psocopteran epiphyte herbivores on larch trees in southern England
Authors: TURNER B. D.
Published: March 2008

ABSTRACT.

The population and biomass dynamics of the collembolan and psocopteran epiphyte herbivores on larch trees at Ranmore Common, Surrey, were followed from October 1976 to October 1978.

The effect of temperature and body weight on the metabolic rate of the epiphyte herbivores was determined in the laboratory.

The metabolic rate of Psocoptera appears little influenced by changes in temperature within the range they normally experience in the field. This‘low Q10 metabolism’is discussed in the light of other studies of species showing a similar phenomenon.

The collembolan metabolism also shows some temperature compensation.

The laboratory studies on metabolic rate are combined with field data to give annual respiration and production estimates.

The data from southern England are compared with published data from northern England sites and their differences discussed.
Seasonal biological variation in some leaf‐miner parasites in the genus Achrysocharoides (Hymenoptera, Eulophidae)
Authors: BRYAN GEORGINA
Published: March 2008

ABSTRACT.

Most Achrysocharoides species and their Phyllonorycter hosts (Lepidoptera, Gracillariidae) have two generations per year in Britain.

In those species with separate sex broods, peak male emergence tends to be earlier than peak female emergence. This female emergence lag is shorter in the second generation.

The mean brood size in the second generation is significantly smaller than in the first in A.cilla males and females, A.latreilli females, mixed sex broods of A.atys, and A.carpini females. A.cilla, A.latreilli and A.niveipes generally have a significantly greater proportion of males in the second generation, but A.atys does not.

There is a shift to killing later instar Phyllonorycter larvae in the second generation, when a much higher percentage parasitism is generally achieved.

The intergeneration differences in sex ratio and brood size may be explained by a change in oviposition behaviour of females of the first and second generations.
The population biology of the Orange Tip butterfly Anthocharis cardamines in Britain
Authors: COURTNEY S. P. , DUGGAN A. E.
Published: March 2008

ABSTRACT.

The population biology of Anthocharis cardamines (L.) is described and shown to vary with locality. Southern and Western populations emerge earlier than Northern ones, but Western and Northern populations occupy similar, wetter habitats and are associated primarily with Cardamine pratensis (L.). Southern populations are recorded mostly from Alliaria petiolata (Bieb.).

Studies on egg and larval survival indicate that host plant‐induced death and parasitization by a tachinid are important mortality factors. However, a key‐factor analysis on one population indicates that the major determinant of population size may be the number of eggs laid by ovipositing females, itself dependent upon weather during the oviposition period. Populations in different localities do show similar trends in abundance, corroborating the effect of weather.

Human effects on distribution and abundance are discussed, and some conservation strategies suggested.
Phenology and intensity of phyllophage attack on Fagus sylvatica in Wytham Woods, Oxford
Authors: PHILLIPSON J. , THOMPSON D. J.
Published: March 2008

ABSTRACT.

Overwintering beech buds began to swell in early April and bud‐break occurred in early May. Most phyllophage attacks were initiated during the 21 day period of leaf growth but additional attacks occurred up to 46 days from bud break.

An average beech tree, with a top height of 24 m and a d.b.h. of 110 cm, bore 420 345 leaves (17% in the upper canopy, 27% in the upper middle canopy, 27% in the middle canopy, 18% in the lower middle canopy and 11% in the lower canopy).

Damage by phyllophages was greatest in the lower canopy; some 75—85% of the leaves were attacked in this stratum and damage amounted to 35% of the total phyllopage damage to the trees.

The major agents of damage in the lower canopy were adult P. argentatus, larval R. fagi and lepidopteran macrophages. Adult R. fagi concentrated their feeding in the upper canopy.

Allowing for damage expansion due to leaf growth the percentages of the total leaf area actually removed, or seriously damaged, by phyllophages were calculated to be 3.43–4.00% in 1978 and 2.37–2.74% in 1979.
Grasshopper populations and weather: the effects of insolation on Chorthippus brunneus
Authors: BEGON MICHAEL
Published: March 2008

ABSTRACT.

In nature, the internal body temperature of Chorthippus brunneus Thunberg is found to be raised substantially under the influence of direct insolation.

In the laboratory, similarly raised body temperatures, resulting from the radiant heat of a light bulb, lead to a 5.6‐fold increase in the rate of development, and a similar or even higher increase in the rate of adult maturation. The rate of egg‐production is even more greatly affected, being negligible in the absence of a radiant‐heat source.

These physiological results provide an explanation for the frequently found correlation between grasshopper abundance and hot and/or dry weather.

The results are also discussed in terms of the problems they pose for the derivation of a physiological time‐scale for basking insects, and the evolutionary forces and constraints that might give rise to them.
Seasonal shifts in host usage in Uroleucon gravicorne (Homoptera: Aphididae) and implications for the evolution of host alternation in aphids
Authors: MORAN NANCY A.
Published: March 2008

ABSTRACT.

Uroleucon gravicome (Patch) feeds on annual Erigeron species and on perennial Solidago species.

To test whether Solidago and Erigeron are analogous to winter and summer hosts of typical host‐alternating aphids, reproductive performance, host preferences, and host associations were measured for E.strigosus, S.juncea and S.nemoralis during spring, summer and autumn.

Caged individuals can reproduce on both genera throughout the season, though colonies are rare on Solidago during summer.

Developmental rate, adult weight, and fecundity decline between May and August on all hosts; however, the drop is least on E.strigosus, intermediate on S.nemoralis, and greatest on S.juncea.

Throughout the season, reproductive performance is at least as great on Erigeron as on Solidago, the difference being least in spring.

Soluble nitrogen content shows the same seasonal trends as reproductive performance, declining in all hosts, but declining least in E.strigosus.

Preference tests and field records show that U.gravicorne moves from Solidago to Erigeron when the first alatae mature in late spring, feeds on Erigeron during the summer, and, in late summer, returns to Solidago where overwintering eggs are laid.

Solidago is not nutritionally superior during spring or autumn; its use during those seasons may result from the need for good oviposition sites.
The natural history of a phoretic sphaerocerid Diptera fauna
Authors: SIVINSKI JOHN
Published: March 2008

ABSTRACT.

Three species of phoretic Sphaeroceridae kleptoparasitize the dung caches of scarab beetles in north Florida. Ceroptera sivinskii Marshall intercepts beetles under dung, then accompanies them into their burrows. Borborillus frigipennis (Spuler) rides on ball rolling and tunnelling scarabs. It perches on beetles both underground and in flight. B.singularis (Spuler) is similar in habits but is principally nocturnal.

Kleptoparasitism is probably a means of escaping environmental decay and competition in‘parent’faeces. Nonscarab competitors and predators are less abundant in beetle stored dung, and Borborillus spp. are among the few spaerocerids that flourish when large, rapidly developing calypterate flies are abundant.

Since oviposition in B.frigipennis occurs only underground, phoresy is an inexpensive and safe means to maintain contact with hosts. Males ride in order to find mates.
The ecology and status of Thymelicus acteon (Lepidoptera: Hesperiidae) in Britain
Authors: THOMAS J. A.
Published: March 2008

ABSTRACT.

A survey was made of the local butterfly, the Lulworth Skipper (Thymelicus acteon Rott.) in Britain. Adult numbers were estimated on most sites and the habitat was analysed. Changes in numbers were also recorded in five populations over 6 years, and some aspects of behaviour were studied.

T.acteon forms closed populations. It was found in great abundance throughout its historical range, and appears both to have increased in numbers and to have spread locally. It has not extended its range.

The wrong larval foodplant is quoted by some modern textbooks. T.acteon requires mature Brachypodium pinnatum Beauv. plants for breeding. Within its range, the butterfly was almost ubiquitous in areas with tall Brachypodium.

The present abundance and probable increase of T.acteon is attributed to the spread of B.pinnaturn in unimproved calcareous grassland. This has occurred through a decline in grazing, both by domestic stock and, since myxomatosis, by rabbits.
Energy partitioning in the Antarctic collembolan Cryptopygus antarcticus
Authors: BURN A. J.
Published: March 2008

Abstract. 1. Consumption, production and assimilation rates were determined for two age groups of Crypropygus antarcticus to give an estimate of energy utilization, and to investigate low temperature adaptation in its energy partitioning.

2. Feeding selectivity shown in laboratory preference tests was supported by gut analysis of field animals from contrasting sites. Although moulting rate was not significantly affected by food type, rates of growth were slowest and mortality highest when fed on a non‐preferred substrate.

3. Both a radio labelling and a more direct method for measuring dry weight consumed gave similar results for Cvpropygus feeding on algae. The consuniption rate for animals when feeding on algae was lower than that on moss peat. The assimilation efficiency for immature animals feeding on algae was 46% and for mature animals was 19%; the values when feeding on moss peat were 7% and lo%, respectively, The net production efficiency ranged from 35%(inimatures) to 13% (matures) and was similar on both substrates.

4. Food consumption exceeded assimilation over the range 2.5–10°C, but the two converged from 2.5 to 0°C. Immature Cryptopygus maintained a net positive energy balance over 0–10°C, whilst below 1S°C respiration exceeded assimilation for mature individuals.

5. An estimate of the annual dry matter consumption (7 g m‐1 y‐1) by Ctypropygus in a moss turf at Signy Island agrees with one based on respiration data alone (Davis, 1981). The consumption at an alga‐dominated site was c. 26 g m‐2 y‐l, and Crypropygus may have a locally limiting effect on net priniary production at such sites.
Mixed function oxidases and herbivore polyphagy: the devil's advocate position
Authors: COULD F.
Published: March 2008

Abstract. 1. Evidence used to support the theory that mixed function oxidases (MFOs) are important in the survival of polyphagous herbivores is briefly reviewed. This evidence includes data on patterns of variation in MFO activity among species and among developmental stages within species. It also includes data on induction of MFO activity by plant compounds and metabolism of plant cornpounds by MFOs.

2. It is argued that the evidence presently available does not offer strong support of the theory because key pieces of information are lacking. Evidence which tends to refute the theory is reviewed and discussed.

3. Experiments are proposed which could more rigorously test the theory.
Effects of cyanogenesis in bracken fern (Pteridium aquilinum) on associated insects
Authors: SCHREINER ILSE , NAFUS DONALD , PIMENTEL DAVID
Published: March 2008

Abstract. 1. The relationship between cyanogenesis in bracken fern and the insect fauna feeding on the plant was investigated over a 3 year period. The most common insects between May and July, while cyanide levels were high, were the sawflies Strongylogaster impressata Provancher, S.multicincta Norton, Aneug‐menus fzavipes (Norton), the aphid Macrosiphum euphorbiae (Thomas) and a microlepidopteran species of Monochroa.

2. Collections of insects from cyanogenic and acyanogenic fronds showed significantly fewer sawflies on the cyanogenic fronds. The aphid and the microlepidopteran were randomly distributed with respect to cyanogenicity.

3. Feeding tests for two of the sawfly species (Simpressata and Smulticincta) showed that larvae grew more slowly and had a higher mortality when raised on cyanogenic fronds than on acyanogenic ones.

4. Field collected cyanogenic bracken fronds were found to have sustained less damage from chewing herbivores compared with acyanogenic fronds.
Food competition among Scotophugu stercoraria Iarvae with emphasis on its effects on reproductive success
Authors: SIGURJÓNSDÓTTIR HREFNA
Published: March 2008

Abstract. 1. Laboratory experiments with yellow dung fly larvae, Scatophaga sfercoraria L. were carried out in the hope of clarifying the causal relationship underlying the extreme variation in body size in wild populations.

2. First, parents were collected in the field and newly hatched larvae exposed to different density levels under two temperature regimes (15°C and 20°C). Second, heritability experiments were done.

3. The results showed that density during the larval stage has a very significant effect on adult size. Male size is more affected than female size and the male larvae spend more time feeding than the female larvae with the result that the males are on average larger. Also, the additive genetic component is of little or no significance, supporting the notion that body size is positively related to fitness.

4. Finally, the results are discussed in relation to field data on the effects of size on both male and female reproductive success.
Limitation of superparasitism by Aphidius rhopalosiphi: a consequence of aphid defensive behaviour
Authors: GARDNER SARAH M. , WARD S. A. , DIXON A. F. G.
Published: March 2008

Abstract. 1. The behavioural mechanisms limiting superparasitism by Aphidius rhopalosiphi (DeStefani‐Perez) are described.

2. A.rhopalosiphi did not discriminate between parasitized and unparasitized aphids, or avoid attacking and ovipositing in previously parasitized aphids.

3. Aphid defensive behaviour was increased for a short period after a parasite stabbing attack. In response to this behaviour the number of parasite stabbing attacks subsequently undertaken declined.

4. Once a stabbing attack had been initiated, parasite oviposition success was unaffected by aphid defensive behaviour.

5. It is concluded that applied defensive behaviour, by limiting the number of stabbing attacks undertaken by A.rhopalusiphi, effectively limits the number of parasite eggs laid and the extent to which super parasitism occurs.
Patterns in the distribution of leaf‐miners on British trees
Authors: GODFRAY H. C. J.
Published: March 2008

Abstract. 1. A multiple regression analysis of the leaf miners on British native angiosperm tree genera was performed using measures of plant range, maximum height, taxonomic isolation and species per genus as independent variables.

2. 69% of the variation was explained by regression.

3. Taxonomic isolation was the most important variable with species per genus also having a significant effect. Plant range had no demonstrable effect.

4. The analysis was repeated with component taxonomic groups of leaf miners. Up to 85% of the variation was explained.
Field studies of foraging behaviour of an intertidal beetle
Authors: RICHARDS LAURA J.
Published: March 2008

Abstract. 1. Adult staphylinid beetles Thinopinus pictus LeC. are noct turnal predators of sand beach amphipods, Orchestoidea califomiana (Brandt). I made continuous observations of Thinopinus near the drift patches on which amphipods feed.

2. Thinopinus alternated between active and ambush foraging modes.

3. Thinopinus had greater attack rates and captured smaller amphipods while in active foraging mode.

4. Thinopinus attacked 0.147 amphipods/min, and captured 9.1% of the amphipods attacked. The attack rate on amphipods increased with the proportion of time spent by Thinopinus in active mode.

5. Thinopinus remained longer near types of drift patches which were more attractive to amphipods.
Species packing and temperature dependent competition among burying beetles (Silphidae, Nicrophorus)
Authors: WILSON DAVID SLOAN , KNOLLENBERG W. G. , FUDGE J.
Published: March 2008

Abstract. 1. Burying beetles are carrion feeders that specialize on small carcasses. We investigated interactions among congeners at two sites in Michigan, U.S.A., that differ in both number and relative proportion of species.

2. Intra‐ and interspecific competition for carcasses is intense. The majority of carcasses are found within 24 h of their placement.

3. Competition between N.arbicollis and N.defodiens is temperature dependent. N.orbicollis can displace N.defodiens on single carcasses, but requires warm temperatures to find the carcasses. Cool weather therefore serves as a refuge for N.defadiens.

4. The southern edge of N.defodien's geographical range is probably determined by competition with N.orbicollis.

5. N.sayi and N.tomenrosus are spring and autumn breeders respectively, and rarely interact with each other or the other two species. Nevertheless, interspecific competition is the most likely evolutionary force leading to seasonal segregation.
Diapause in a large aggregation of a tropical beetle
Authors: WOLDA HENK , DENLINGER DAVID L.
Published: March 2008

Abstract. 1˜ Diapause is described for adults of Stenotarsus rotundus Arrow (Endomychidae, Coleoptera) in the tropical lowland forest on Barro Colorado Island, Panama.

2. Diapause lasted up to 10 months each year, covering some 6 months of the wet season plus 4 months of the dry season. When in diapause the beetles clustered in an aggregation of up to 70,000 individuals on the stem of a palm tree, the same individual palm tree in at least four successive years.

3. The habitat and habits of the beetle when not in diapause are unknown, but one or two generations may be produced during this period. Beetles returned to the diapause site from June until late August.

4. Soon after arrival at the diapause site the flight muscles degenerated and did not develop again until February/March. The ovaries were undeveloped when the beetles arrived at the site and remained in that condition until the onset of yolk deposition in March. At the beginning of the rainy season in April the beetles mated and dispersed.

5. Lean dry weight of the beetles did not decrease noticeably during diapause, but fat content did. It is suggested that the beetles do not feed, or feed very little, while in diapause. During diapause, the metabolic rate is surprisingly low considering a mean ambient temperature of 25° C.

6. Juvenile hormone analogue (ZR515) stimulated flight muscle and ovary development. Daylength, when different from LD 12:12, initiated a partial flight muscle development, but there was no effect on the ovaries. Field observations suggest that neither temperature nor humidity had an effect on the termination of diapause.

7. Although the development of both flight muscles and ovaries were stimulated by juvenile hormone analogue and both developed around March of each year, it is suggested that the mechanisms causing this development are different.
Responses of leaf miners to atypical leaf production patterns
Authors: AUERBACH MICHAEL , SIMBERLOFF DANIEL
Published: March 2008

Abstract. 1. Larvae of two bivoltine species of leaf‐mining Lepidop‐tera, Acrocercops sp. and Neurobathra strigifinitella (Clem.), restrict feeding to young, second‐flush leaves of their host trees in north Florida.

2. During 1980 and 1981, densities of both species varied greatly among thirty small water oaks (Quercus nigra), as did timing and extent of secondary leaf production.

3. In both years leaf‐miner density at the end of the first generation (mid‐August) was positively correlated with secondary leaf production.

4. Five trees abscised their leaves and reflushed new ones at atypical times of the growing season. When refoliation coincided with emergence of ovipositing adults, Acrocercops sp. and N.strigifinitella densities increased dramatically, indicating that both species are at times limited by availability of young leaves.

5. By staggering termination of diapause these leaf miners can exploit a temporally variable resource.
Size‐related selection of food plants by bumblebees
Authors: BARROW D. A. , PICKARD R. S.
Published: March 2008

Abstract. 1. A positive correlation between the tongue length of conspecific workers collecting nectar from seven plant species and the corolla length of the flowers probed was found for B.lapidarius and B.pascuomm but not B.terrestris. No simple relationship was found between the volume, sugar weight or concentration of nectar in flowers and the tongue or wing length of probing bees.

2. B.terrestris workers collecting pollen from four plant species producing pollen only, were found to differ in size according to the type of pollen presentation mechanism and the pollen content per flower. Body size variation was also related to the foraging of pollen plus nectar from two other plant species.
The harvester ant (Pogonomyrmex badius) midden: refuse or boundary?
Authors: GORDON DEBORAH M.
Published: March 2008

Abstract. 1. P.badius Latreille, a harvester ant of the southern U.S.A., surrounds its nest mound with small bits of charcoal, previously believed to be incidental refuse, along with other components of the colony's midden.

2. Charcoal middens were removed from the nest mounds of colonies in northern Florida. These colonies collected new charcoal and replaced the middens within 7 days.

3. Activity rhythms, use of space, and interspecific aggression were compared in experimental and control colonies. When middens were removed, the frequency of invasions of the nest mounds by other species of ants increased. Foreign ants circled the nest mound and interfered with colony activities. Increased numbers of invading ants led to an increase in patrolling and defensive behaviour by the P.badius colonies.

4. The charcoal midden is not merely refuse. Instead, it acts as a boundary that deters ants of other species from coming onto the P.badizls nest mound. Ants may use charcoal bits as a repository of a chemical substance functioning as a territorial marker.
Carrot fly cultivar preferences: some influencing factors
Authors: GUERIN PATRICK M. , STADLER ERICH
Published: March 2008

Abstract. 1. Factors affecting cultivar preferences by the carrot fly Psila rosae F. were examined in choice tests using foliage from carrot lines representing extremes of resistance and susceptibility to attack.

2. Flies were offered a choice to oviposit on foliage, artificial substrates impregnated with leaf surface extracts or enclosed in vapours of different cultivars to establish the importance of contact and olfactory stimuli. Susceptible cv. Danvers Half Long 126 foliage was preferred over that of resistant cvs. Clause's Sytan Original and Tip‐Top. But, whereas the Sytan leaf surface extract was as effective as that of Danvers, the surface extract of Tip‐Top was very much inferior as an oviposition stimulant. By contrast, Sytan and Tip‐Top foliar vapours were both more attractive to the fly than that from Danvers.

3. Headspace vapours over Sytan foliage evoked significantly higher electroantennogram responses than those from Danvers.

4. Cold‐trapped foliar volatiles of Sytan and Danvers were analysed by gas chromatography linked with antennographic detection. Foliage of Sytan released, among other chemo‐stimulants, higher levels of host plant attractants, i.e. green leaf aldehydes and the phenylpropanoids, trans‐asarone and trans‐methylisoeugenol.

5. These findings indicate that olfactory and contact chemostimuli may be involved in preferences shown by the carrot fly for carrot cultivars, but these factors alone do not fully account for the preferences observed.
The suitability of damaged willow leaves as food for the leaf beetle, Phgiodera versicolora
Authors: RAUPP MICHAEL J. , DENNO ROBERT F.
Published: March 2008

Abstract. 1. The effect of previous damage on the suitability of willow (Mix bubylonicu and S.ulbu‘Tristis’) leaves as food for the imported willow leaf beetle, Plugiodera versicoloru Laich. (Coleoptera: Chrysomelidae), was evaluated by feeding adults and larvae leaves from damaged and undamaged branchlets.

2. Females had lower fecundity when fed leaves from artificially damaged branchlets of S.ufba‘Tristis’. A similar result was obtained when beetles ate leaves from naturally damaged branchlets of S.babylonica.

3. Feeding preference tests suggest that the reductions in leaf suitability were not due to adults avoiding damaged leaves as a food source.

4. PZugiodera versicolora larvae required longer to develop and attained a lower adult weight when fed leaves from damaged branchlets.

5. Changes in leaf suitability brought about by herbivore feeding may affect the seasonal abundance of P.versicoloru on its willow hosts.
The life cycles and growth of Carabus glabratus and C. violaceus in Budalen, central Norway
Authors: REFSETH DAGFINN
Published: March 2008

Abstract. 1. The seasonal activity patterns of adults and larvae, and the seasonal development of female gonads showed that Curubus glabrafus Payk. and Curubus violaceus L. living in a subalpine habitat are spring (summer) breeders with biennial life cycles.

2. As a rule, the adults and third stage larvae hibernate, but C.glubrutus at least can hibernate also at the second larval stage, particularly in years in which unfavourable climatic conditions in the spring delay breeding.

3. The adaptive strategies underlying these life history patterns and their possible significance for species diversification and coexistence are discussed.
Can honey bees change foraging patterns?
Authors: WELLS PATRICK H. , WELLS HARRINGTON
Published: March 2008

Abstract. 1. Foraging patterns were studied using honey bees on artificial flower patches to determine if given individuals could change behaviours under differing conditions.

2. Two types of flower patches were used; those simulating a population of flowers, dimorphic for colour, and grids simulating a single colour‐dimorphic inflorescence.

3. In the simulated population of flowers bees were individually constant to colour over a range of reward volumes and flower patch sizes.

4. Each bee remained individually constant to a flower morph when visiting a population‐type grid but changed to random visitation on the simulated inflorescence.

5. On the simulated inflorescence, with morphs providing unequal qualities of reward, most bees foraged on the higher molarity morph.

6. Most, but not all bees, failed to minimize uncertainty on the simulated inflorescence.

7. On the simulated inflorescence, bees failed to optimize when one morph provided a greater reward volume than did the other.

8. In the population of flowers bees flew from flower to flower, whereas, they walked on the simulated inflorescence.