bluuebunny/crossref_metadata_2025 huggingface dataset:
Biology and bionomics in Scotland of Anthocoris gallarum‐ulmi
Authors: PARKER N. J. B.
Published: March 2008

Abstract. 1. Observations were made on the biology of Anthocoris gallarumulmi De Geer (Hemiptera ‐ Heteroptera: Anthocoridae) in West Central Scotland from 1973 until 1975. The life cycle was intimately linked with those of its principal prey species Schizoneura ulmi and S.patchae, leaf roll‐gall aphids, and elm, their primary host (Ulmus sp.).

2. Overwintered adults emerged in late April/May and could be found on a number of early flowering tree species, before congregating on elm in late May/June. This population was univoltine and exhibited obligatory female reproductive diapause.

3. Overwintered females emerged already mated but the subsequent pre‐oviposition period was 25 days and oviposition period 27 days. Ova were deposited only in close association with galls of S.ulmi and Spatchae, and behavioural variations were shown between sites. Fecundity was c. 16 ova per female.

4. The incubation period was c. 8 days with the subsequent period of larval development 38–53 days, during which time the diet was almost exclusively either S.ulmi or S.patchae. Intergall migration was characteristic of post second instar larvae, which resulted in the concentration of fifth instar larvae and adults in a limited number of galls. It was during this period of local high population density that mating occurred.

5. Adults left elm within 14 days of imaginal ecdysis and thereafter, until overwintering, were recorded in only very low numbers from a range of tree, shrub and herb species.

6. Overwintering adults selected as hibernacula the bark of four tree species but principally Acer pseudoplatanus and Quercus robor. Females required a period of at least 75 days of cold ‘shock’ to terminate reproductive diapause.

7. Mortality among males surviving to spring emergence was 67%.
Fluctuations in the abundance of butterflies, 1976–82
Authors: POLLARD E.
Published: March 2008

Abstract. 1. A scheme for monitoring the abundance of butterflies at about eighty sites in Britain is described.

2. Indices of abundance are presented for twenty‐nine species for the years 1976–82.

3. There are marked differences between species in the scale of annual fluctuations.

4. Some species show correlations between successive index values; for example the summer generation index of Pieris brassicae is highly correlated with the spring generation index.

5. The annual changes in the index values of many species are highly Correlated. The index values themselves also show positive correlations, but these are less strong.

6. The drought of 1976 is believed to have severely depressed populations of many species in 1977.

7. The data do not indicate any general fall in butterfly numbers over the period at the sites in the scheme.

8. The sites are not representative of the countryside as a whole, but, for a number of species, it is considered that the index values reflect wider trends.
Burying beetles: intraspecific interactions and reproductive success in the field
Authors: WILSON DAVID SLOAN , FUDGE JULIE
Published: March 2008

Abstract. 1. The discovery and utilization of small carcasses by burying beetles (Silphidae, Nicrophorus) was studied by placing dead mice at random points on large grids at two Iocations in Michigan, U.S.A.

2. The majority of mice are found within 24 h by more beetles than ultimately will utilize the carcass. If a carcass is likely to be usurped by a larger species of beetle or by a vertebrate, then intraspecific competition may be postponed until the carcass is concealed and buried.

3. Both males and females practice parental care. Maturing broods are tended by no adults, a single female, a single male, or a male—female pair. No differences in brood success were observed among these categories.

4. The female lays a larger clutch than ultimately will survive. Brood size is regulated after the egg stage, such that offspring number varies, but individual offspring size does not.

5. A large amount of unexplained variation exists in brood size, in both the laboratory and the field. This variation is probably caused by the environment, and not the reproductive physiology of the beetles. Competition with microbes is a likely candidate.

6. Differences exist not only between Nicrophorus species, but also between localities for a single species, suggesting adaptation to local environments.
Host‐plant shifts and adult survival in the cactus breeding Drosophila mojavensis
Authors: BRAZNER JOHN , ABERDEEN VIRGINIA , STARMER WILLIAM T.
Published: March 2008

Abstract. 1. In order to gain insight into how Drosophila mojavensis Patterson and Crow (which lives on the rotting tissue of cactus) successfully shifted host plants, from an Opuntia species to columnar cactus species, over evolutionary time, specific components of columnar cactus and Optunia tussue were examined for their effects on adult longevity.

2. The availability of free sugars affects the survival of adult D.mojavensis. The addition of a sugar to columnar cactus tissue significantly increased the longevity of adults that fed on those tissues. This increase in adult longevity was equal to the longevity observed on unsupplemented Opuntia tissue, which has free sugars present.

3. Live microorganisms added to Opuntia tissue had a slight detrimental effect on adult longevity (longevity was decreased by approximately 1 week).

4. Low concentrations of atmospheric ethanol (independent of diet) increased the longevity of adult D.mojavensis to levels comparable in magnitude to that provided by the addition of free sugars to the diet.

5. This information and the apparent lack of a year‐round supply of free sugars for D.mojavensis in nature suggests that the ethanol (produced by fermentation) rather than free sugars per se is the most important component of rotting cactus tissue for the survival of this species and may explain its successful host‐plant shift.
Honeydew: an arrestant stimulus for coccinellids
Authors: CARTER M. C. , DIXON A. F. G.
Published: March 2008

Abstract. 1. The presence and quantity of honeydew, produced by the, cereal aphid, Sitobion aveme (Fab.), on the time Coccinella seprempunctara L. larvae spent searching ears of wheat and on the number of aphids eaten, was investigated.

2. In the presence of honeydew larvae spent longer searching the ears, resulting in a greater exploitation of prey than in the absence of honeydew.

3. Larvae did not respond to differences in the amount of honeydew, so that the arrestment response would not result in aggregation in areas of high prey density.
Phenology of weight, moisture and energy reserves of Australian monarch butterflies, Danaus plexippus
Authors: JAMES DAVID G.
Published: March 2008

Abstract. 1. In the Sydney area of New South Wales, dry weights of reproductive monarch butterflies averaged 156 mg and were higher during winter than in other seasons. Dry weights of non‐reproductive monarchs ranged from 216 to 324 mg and declined by 15–25% during over wintering.

2. Fat in reproductive butterflies ranged from 0.009 to 0.017g/0.1g dry weight and was lower during winter than in other seasons. Fat content of non‐reproductive monarchs was higher (0.019–0.037 g/0.1g) and declined by 24–51% during over wintering.

3. Lean dry weights of reproductive monarchs were lower than those of non‐reproductive individuals. Lean dry weights of non‐reproductive butterflies increased rapidly at the beginning of over wintering and remained high throughout the winter. Analysis of protein content indicated the higher lean weight of non‐reproductive monarchs was due to greater protein levels.

4. Moisture content of monarchs did not vary with season or reproductive status and appeared to be correlated with ambient humidity.

5. Non‐reproductive monarch butterflies in New South Wales adjust bio chemically during over wintering. Energy reserve dynamics of these butterflies are comparable to those that occur in non‐reproductive monarchs in North America.
The probing behaviour of nymphs of Vanduzeea arquata and Enchenopa binotata (Homoptera: Membracidae) on host and non‐host plants
Authors: KISS AGNES , CHAU ROBERT
Published: March 2008

Abstract. 1. Nymphs of Vanduzeea arquata Say have been found to be more host‐specific in nature and to show a higher degree of selectivity in host discrimination experiments than nymphs of Enchenopa binotata (Say), It was hypothesized that this differential selectivity would be reflected in the probing behaviour of individuals placed on twigs of host and non‐host plants. Probing behaviour was examined by direct observation of nymphs and by sectioning and staining the probed plant tissues.

2. All nymphs probed readily and for extended periods on both host and non‐host twigs. E.binotuta nymphs showed no consistent differences in probing behaviour on hosts versus non‐hosts, but V.atquuta nymphs were more likely to withdraw their stylets within 60 s when on non‐host twigs and produced honeydew only when on their host species. V.urquatu nymphs reached the phloem sieve elements only when on host twigs and broke many cells in peripheral plant tissue layers while probing. E.binotata nymphs broke few cells and often reached the phloem of non‐host as well as host plants.

3. Nymphs of V.arquata always reject non‐host plants, apparently in the course of probing and prior to encountering the phloem sap. Chemical compounds released from ruptured parenchyma cells may act as probing stimulants or inhibitors. E.binotura nymphs often feed on non‐host plants in a non‐choice situation; their preferential settling on host twigs in discrimination experiments may reflect a tendency to abandon non‐host twigs more readily than host twigs.
Alternative reproductive routines in a small fly, Puliciphora borinquenensis (Diptera: Phoridae)
Authors: MILLER P. L.
Published: March 2008

Abstract. 1. Puliciphora borinquenensis (Wheeler), a very small phorid fly in which the female is apterous, breeds in small patches of decomposing organic matter such as dead insects.

2. Females leave the shelter of oviposition sites during the afternoon and ‘parade’ in exposed places making vigorous abdominal pumping movements which probably help to disperse a pheromone.

3. Males exhibit one of four reproductive routines. In the first they perform rapid sequences of stationary copulations with different parading females, achieving rates of 0.66 females min‐1 for periods of 30min (Al). In the second (A2) they wait on oviposition sites and grab non‐parading females which have recently arrived.

4. In the third routine a male airlifts a parading female in copula to an oviposition site (Bl); in the final type of routine, females are airlifted and then deposited randomly when oviposition sites cannot be found (B2).

5. Males are able to learn the location of oviposition sites and this enables them to transport large numbers of females (up to thirty‐three per male) to sites at a high rate (0.5 females min‐1).

6. Immediately a female is released after a B routine, the male follows her closely for up to 10s. This is thought to represent a phase of non‐contact guarding, suggesting the occurrence of sperm competition.

7. Individual males persist with either A or B routines for long periods (c. 30 min), but they are able to switch between routines.

8. Young males (< 27 h after emergence) carry out A routines 18 times more commonly than B routines, whereas older males carry out A routines only 1.6 times more commonly than B routines. The choice between A and B routines in older flies does not depend on male or female density.

9. Males benefit from B routines because the eggs they fertilize are likely to reach oviposition sites, but they pay a considerable energy cost. A routines, on the other hand, are energetically cheaper, but mated females are less likely to reach oviposition sites unless they are subsequently transported by B males. An A male can then benefit provided his sperm are not completely displaced by the second male.
Poly modal emergence of the tiger swallowtail, Papilio glaucus (Lepidoptera: Papilionidae): source of a false second generation in central New York State
Authors: HAGEN ROBERT H. , LEDERHOUSE ROBERT C.
Published: March 2008

Abstract. 1. The tiger swallowtail butterfly, Papilio glaucus (L.) (Lepidoptera: Papilionidae), is commonly assumed to have a bivoltine life cycle in central New York State and other parts of the northeastern United States. The seasonal abundance of adults in Tompkins County, New York, shows a bimodal pattern in some years, and a skewed unimodal pattern in others. We studied the incidence of diapause, the potential for successful development of two generations in the field, and the dates of adult emergence from overwintering pupae to determine whether these seasonal patterns are the result of bivoltinism.

2. Insects from Tompkins County, reared as larvae under 16L:8D photoperiod, uniformly enter pupal diapause.

3. Comparison of the heat units required for successful development of two generations with the heat units available in the field during 11 years shows that emergence of non‐diapausing individuals would occur too late in the summer to contribute to the second peak of butterfly abundance. Offspring of non‐diapausing individuals could only rarely complete development before the end of the growth season.

4. Diapausing offspring of butterflies collected in early June and late July differed sufficiently in dates of emergence to account for the field pattern of seasonal abundance.

5. Electrophoretic studies revealed no evidence of genetic isolation between early and late emerging butterflies.

6. These results suggest that polymodal emergence of diapausing insects can masquerade as a bivoltine life cycle.
Does the bird cherry have its ‘fair share’ of insect pests? An appraisal of the species—area relationships of the phytophagous insects associated with British Prunus species
Authors: LEATHER SIMON R.
Published: March 2008

Abstract. 1. Field and published data reveal that there are at least twenty‐three species of phytophagous insects associated with Prunus padus L. in Britain. Most of these species occur on the tree between May and September. Interspecific competition does not appear to be severe.

2. There are a total of 196 species of phytophagous insects feeding upon the various tissues of P. avium, P. cerasifera, P. cerasus, P. domestica, P. laurocerasus, P. padus and P. spinosa.

3. A highly significant species (5)‐distribution (A) relationship of the form In (S+l)=0.92 In A‐2.19, was obtained for the Prunus species examined within Britain (excluding Ireland), i.e. the wider the distribution of the plant the greater the number of insect species associated with it.

4. However, critical analysis of the data indicate that P. padus does not support as many different insect species as expected.

5. Neither plant form nor age of establishment within the British Isles accounted for this discrepancy.

6. The possibility of using a plant's insect fauna to describe its relationship to other plants in the same genus is discussed.
Differences in insect species richness and faunal composition of birch seedlings, saplings and trees: the importance of plant architecture
Authors: FOWLER SIMON V.
Published: March 2008

Abstract. 1. Data are presented on the species richness and faunal composition of herbivorous insects on birch seedlings, saplings and trees at one site in Northern England.

2. Species richness of insect herbivores in equal‐sized samples from birch seedlings and trees was similar through most of the season.

3. Effects of plant architecture were confined to the first sampling date, when seedling faunas were species poor compared with trees – possibly due to safe overwintering sites on the extensive bark, twigs and buds of trees.

4. The faunal composition of birch seedlings, saplings and trees was also similar. Out of a total of 112 recorded species of herbivores, only one aphid species was confined to seedlings.

5. Similarly, no evidence for clear‐cut vertical stratification of insects within trees was found.

6. Species turnover as host plants mature (‘horizontal’ stratification) and vertical stratification within trees add little to the high overall species richness of birch‐feeding insects in Britain, contrary to the predictions of Lawton (1983).
Indian migrant butterflies displaced to Arabia by monsoon storm ‘Aurora’ in August 1983
Authors: LARSEN T. B. , PEDGLEY D. E.
Published: March 2008

Although many insect species are now thought to travel hundreds and even thousands of kilometres on the wind (Pedgley, 1982) only a few are butterflies. Three species for which there is reasonably convincing but circumstantial evidence are Danaus plexippus L. from the U.S.A. to the British Isles (Hurst, 1969), Hypolimnas bolina nerina (F.) from Australia to New Zealand (Tomlinson, 1973) and Nymphalis antiopa L. from northern Europe to the British Isles (Chalmers‐Hunt, 1977). In this paper we describe the sudden appearance of Indian butterflies in Arabia and provide evidence that they were windborne across the Arabian Sea.
Downwind migration of the African army worm moth, Spodoptera exempta, studied by mark‐and‐capture and by radar
Authors: ROSE D. J. W. , PAGE W. W. , DEWHURST C. F. , RILEY J. R. , REYNOLDS D. R. , PEDGLEY D. E. , TUCKER M. R.
Published: March 2008

Abstract. 1. About 166,000 African armyworm moths, Spodoptera exempta (Walk.), were marked at an emergence site near Nairobi when they fed at night on trees baited with dyed molasses.

2. Six marked moths were captured in pheromone traps, including one at 90 km after flying for only one night, and another at 147 km.

3. Moth flight trajectories deduced from radar and from marking showed that migration was downwind.

4. During migration, moths become dispersed; hence the high densities that lead to outbreaks must be produced by concentration.

5. Some moths were ready to mate on the same night they completed their long‐distance flight.
Inverse density dependent parasitism in a patchy environment: a laboratory system
Authors: HASSELL M. P. , LESSELLS C. M. , McGAVIN G. C.
Published: March 2008

Abstract. 1. Two species of parasitoids (Anisopteromalus calandrae (Howard) and Heterospilus prosopidis Vier) attacking the bruchid beetle, Callosobruchus chinensis (L.), show marked inverse density dependent relationships between per cent parasitism and host density per patch.

2. These patterns are well described quantitatively using data on the spatial distribution of searching time by the parasitoids and their attack rates on patches of different host density.

3. A model of optimal foraging predicts just the opposite (i.e. density dependent) patterns of parasitism.

4. Both density dependent and inversely density dependent spatial patterns of parasitism can be explained mechanistically in terms of (a) the allocation of searching time in patches of different host density and (b) the maximum attack rate per parasitoid that constrains the extent of host exploitation within a patch.
Relationships between larval density, adult size and egg production in the cowpea seed beetle, Callosobruchus maculatus
Authors: CREDLAND PETER F. , DICK KENNETH M. , WRIGHT ANDREW W.
Published: March 2008

ABSTRACT.

The eggs of the cowpea seed bettle Callosobruchus maculatus (Fab.) are attached to cowpeas. On hatching, the larvae penetrate the testa and remain in the seed until development is complete and adult eclosion has occurred. The adults do not need to feed and were not allowed to do so.

Strains from Brazil and Nigeria can produce more than twelve adults from a seed bearing numerous eggs, whereas a strain from the Yemen Republic rarely produced more than three.

In all three strains the mean weight of the adults produced from a single cowpea declined with increasing initial larval density in the seed.

Egg production by females is positively correlated with their weight at the time of mating, shortly after emergence.

Lifetime egg production by females of the Brazilian and Nigerian strains was lower if they came from cowpeas with higher initial larval densities. No such relationship could be demonstrated in the Yemen strain.

The fecundity of one generation of these beetles, at least in some geographical strains, is significantly affected by the number of larvae entering the hosts in which the adults of that generation have developed.
Detection of activity cycles of tsetse from capture–recapture data
Authors: ROGERS DAVID J. , RANDOLPH SARAH E.
Published: March 2008

ABSTRACT.

Activity cycles of female tsetse (Glossina palpalis palpalis Robineau‐Desvoidy) in the field are contrasted with those of males, using mark‐release‐recapture data from continuous biconical trap samples over a period of 80 days in two villages in Ivory Coast.

Variability in recapture rates was examined using the techniques of autocorrelation and spectral analysis. In order to do this a two‐dimensional diffusion model incorporating both mortality and emigration was first fitted to corrected recapture rate data to produce a trend line, deviations from which were subjected to the analysis.

The autocorrelations for the data for males suggest considerable variability in activity, presumably associated with feeding, around a mean period of about 4 days in one village and seven in the other.

Data for females show a strong regular periodicity of about 9–10 days, reflecting the pregnancy cycle, and shorter, more variable periodicities probably corresponding to feeding.
Habitat segregation in four species of adult tiger beetles (Coleoptera: Cicindelidae)
Authors: GANESHAIAH K. N. , BELAVADI V. V.
Published: March 2008

ABSTRACT.

Habitat segregation in four species of tiger beetles, Cicindela cancellata Dejean, C.cardoni Fleutians, C.minuta Olivier and C.sumatrensis Herbst in a river bank ecosystem was studied in dry and wet seasons.

The four species segregated distinctly along the river beds into separate habitats, with occasional overlapping in both the seasons.

Among the habitat characteristics considered, vegetation, soil moisture and available prey‐size were found to be important in species segregation.

D
2‐analysis showed that the habitat preferences of C.cardoni and C.cancellata were closer to that of C.sumatrensis. The habitat of C.minuta was distinctly separated.

There was a positive correlation between the mandible length of each tiger beetle species and the length of prey captured.

Variance in mandible length within species was related to prey‐length distribution pattern and to variance in habitats.
Temperature and the colour polymorphism of Philaenus spumarius (Homoptera: Aphrophoridae)
Authors: BERRY A. J. , WILLMER P. G.
Published: March 2008

ABSTRACT.

The spittle bug, Philaenus spumarius (L.), has eleven distinct elytral colour pattern morphs in Britain, of which three are designated non‐melanic and eight melanic. Frequencies of different morphs vary between populations.

The role of thermal factors in the maintenance of the balanced polymorphism was investigated by measurements of dorsal reflectance and body temperature when artifically irradiated.

Non‐melanic forms had higher reflectances and showed lower temperature excesses when irradiated. There was considerable variation in reflectance for the populi–typicus morph group, and trilineatus is therefore the only true‘non‐melanic’morph.

For samples along altitudinal transects in three Scottish glens, trilineatus frequencies were found to be negatively and populi‐typicus and melanic frequencies positively correlated with altitude.

Thermal considerations do therefore play some role in the broad and complex selection regime of P.spumarius.
Insects on isolated colonies of common rock‐rose Helianthemum chamaecistus
Authors: DAVIS B. N. K. , NERC P. E. JONES
Published: March 2008

ABSTRACT.

A study was made of the insect species present on twenty‐eight colonies of H.chamaecistus Mill, in 1978 ranging in size (cover) from 0.4 m2 to about 6500 m2 and separated from nearest large neighbours by distances up to 6.5 km. Twenty‐three insect species were collected of which nine or ten were more or less monophagous.

There was a clear relationship between species richness and size of host colony. Sites with less than 30 m2 of rock‐rose, about 67% of those in the study area, were likely to have less than half of the monophagous species. Distance to neighbouring colonies did not contribute significantly to species richness.

The consistency of results from year to year was examined at five sites re‐sampled in 1979. The 1978 data were also used to compare‘expected’and observed faunas at five new sites sampled in 1979 based upon the species‐area relationship and the relative frequency of species at known sites.

Insect dispersal was examined using a suction trap placed near the largest rock‐rose site. Colonization of new sites was studied by experimental outplanting of pot‐grown plants.

These direct observations, and the monitoring of fourteen sites for 5 years, suggested that colonization and interchange of faunas were rare events. The experimental introduction of one to five species at four sites showed in several cases that the sites were suitable for the species, and that introduction could significantly enhance a site's complement.
Studies in the distribution of insects by aerial currents. III. Insect drift over the sea
Authors: HARDY ALASTAIR C. , CHENG L.
Published: March 2008

ABSTRACT.

Aerial samples caught in nets slung from ships mastheads contained predominantly small, weak‐flying insects.

From over 102 trips with a total sailing time of over 1151 h, some 1825 insect specimens were collected.

In a specified area over the North Sea more than 160 km from land (seventy‐five samples), catches averaged 1 insect h−1; in the English Channel, in a smaller area more than 80 km from the coasts, hourly catches averaged 4 insects h−1.

Lists of orders, families, genera and species caught are appended.

Aphids, which constituted more than 60% of the total, apparently originated mostly from the west or north‐west, i.e. from Europe, whereas most other insects seem to have originated from the north‐east and south, i.e. from Britain.

These data have implications for the spread of agricultural pests to and from Britain.
Leaf buds, a factor in host selection by Battus philenor butterflies
Authors: PAPAJ DANIEL R.
Published: March 2008

ABSTRACT.

Field and laboratory experiments identified a character intrinsic to Aristolochia reticulata Nutt. host plants, the terminal leaf bud, that is involved in host‐selection behaviour by female pipevine swallowtail butterflies (Battus philenor L.) searching for oviposition sites.

In the field, the frequency with which females landed on non‐host buds declined seasonally as the proportion of host foliage that consisted of buds decreased. Female butterflies did not land on non‐host species in proportion to their abundance; rather, females landed on those non‐host species whose buds resembled those of A.reticulata.

A.reticulata plants whose terminal leaf bud was concealed by plastic tape were less susceptible to oviposition in the field than were control plants.

Female butterflies released in a large, outdoor enclosure were conditioned to search for leaf buds only when exposed to a host species bearing a prominent terminal leaf bud.

The significance of conditioning of leaf‐bud searching behaviour is discussed with respect to discrimination between hosts and non‐hosts, between host species, and among plants within a host species.
Sphaeroceridae (Diptera) caught in light traps at Rothamsted Experimental Station, Herts., 1980–83
Authors: PITKIN BRIAN R.
Published: March 2008

ABSTRACT.

A total of 7063 specimens of Sphaeroceridae representing forty species were caught in four light traps, two in woodland and two in the open, at Rothamsted Experimental Station between December 1980 and December 1983.

A complete list of species and the numbers of individuals of each is provided.

The catches in the two traps in woodland were less diverse than the catches in the two traps in the open.

Two‐way analysis of variance demonstrated a significant difference in catch from trap to trap.

When their similarities were compared, the four light trap catches formed two groups, corresponding with habitat type.

The majority of the catch were Copromyza similis (Collin) (5555 specimens or 78.64% of the total). The species was most abundant in winter from mid‐December to early February, although there were slight differences in times of maximum abundance between open and woodland habitats.
Reproductive variation and adult size in two co‐occurring grasshopper species
Authors: ATKINSON DAVID , BEGON MICHAEL
Published: March 2008

ABSTRACT. 1. Egg sizes and clutch sizes of the grasshoppers Chorthippus brunneus (Thunb.) and Myrmeleotettix maculatus (Thunb.) were compared among three years and among three sites less than 1.3 km apart. Relationships between these reproductive traits and date of egg laying, body size and body condition were sought.

2. M.maculatus, the smaller species, laid fewer but larger eggs; and only the eggs of this species showed significant differences between sites and years.

3. A negative correlation between egg size and number per clutch was evident between species and years, but generally not among sites and among individuals of a population.

4. However, a hidden negative correlation between egg size and number was uncovered within populations when the relationship was examined for females of a given mature weight.

5. Variation in the number of eggs per clutch was explained statistically by a positive relationship between female body weight and egg number. Also, both interpopulation and intrapopulation comparisons revealed that for M.maculatus, but not for C.brunneus, females with long hind femurs laid large eggs.
Causation, fitness effects and morphology of macropterism in Chorthippus parallelus (Orthoptera: Acrididae)
Authors: RITCHIE M. G. , BUTLIN R. K. , HEWITT G. M.
Published: March 2008

ABSTRACT. 1. Chorthippus parallelus (Zett.) displays an apparent‘flight polyphenism’despite the fact that macropterous individuals cannot fly.

2. Photoperiod is used as an environmental cue controlling the polyphenism: long day lengths increasing the proportion of macropterous adults.

3. Macropterous females start mating when older and are less fecund than brachypters.

4. In contrast to other studies the response may not be due to cues associated with a reduced environmental quality and we speculate that macropterism is not a dispersal mechanism in the Gomphocerinae.
Evidence of autumn overseas migration in the rice planthoppers, Nilaparvata lugens and Sogatella furcifera: analysis of light trap catches and associated weather patterns
Authors: WADA TAKASHI , SEINO HIROSHI , OGAWA YOSHIO , NAKASUGA TAKAMASA
Published: March 2008

ABSTRACT. 1. Daily trap catches of the rice planthoppers, N.lugens Stal and S.furcifera Horvath, and associated synoptic weather patterns were analysed in Kyushu, south‐west Japan, in the autumns of 1980–85.

2. Certain weather patterns which seemed to favour overseas immigration, were reflected in trap catches: of eighteen occasions in which back‐tracks on 850 mbar wind fields reached central China, marked mass catches in a light trap occurred on six occasions, and peaks in catch curves were found on another seven occasions.

3. These results strongly imply overseas immigration of the planthoppers from China to Kyushu in autumn, identical to invasions by the same species in early summer. However, such autumn migration is apparently non‐adaptive because migrants or their progeny are soon killed by cold weather.
Opposing effects of spring defoliation on late season oak caterpillars
Authors: HUNTER MARK D.
Published: March 2008

ABSTRACT. 1. The pedunculate oak, Quercus rohur L., suffers high annual levels of spring defoliation in Wytham Woods. near Oxford.

2. This spring defoliation affects late season caterpillars through a variety of damage‐induced changes in the leaves.

3. Diurnea fagella (D. & S.), one of the commonest late season caterpillars, shows reduced larval survival and pupal weight on regrowth foliage when compared to undamaged primary foliage.

4. D. fagella also suffer higher larval mortality on naturally damaged primary foliage than they do on undamaged foliage.

5. Despite this, the three commonest late season caterpillar species are more abundant on damaged trees than undamaged ones. and their distributions are biased towards damaged leaves within the canopy.

6. Other factors that may be more important than leaf damage in determining the distribution and abundance of late season caterpillars are discussed. D.fagella larvae spin their larval refuges more rapidly on damaged than undamaged foliage, and this may reduce mortality by natural enemies, or ameliorate adverse effects of weather.
Grass flowers in the diet of Megaloceraea recticornis (Heteroptera: Miridae): plant structural defences and interspecific competition reviewed
Authors: WEITON M. N. , GIBSON C. W. D.
Published: March 2008

ABSTRACT. 1. Megaloceraea recticornis (Geoffroy) is the most common of seven species of stenodemine bugs on a calcareous grassland in Oxfordshire. Previous work indicated that it competed with a related species, Notostira elongata Geoffroy, by behavioural interference at the feeding site. Both bugs were thought to eat only grass leaves.

2. The importance of grass flowers in the diet of M.recticornis was studied in the laboratory. This bug completes its development only by feeding on grass flowers; grass leaves do not suffice.

3. M.recticornis is unusual among phytophagous insects in that its later instars can eat flowers of the grass Brachypodium pinnatum L. The hard lemma and palea surrounding these flowers inhibit feeding by young bugs. The age of the flowers also affect bug feeding success.

4. The result of field experiments, which previously appeared to show competition between M.recticornis and N.elongata, are discussed in the light of the present findings. It now seems that M.recticornis may not suffer from competition with N.elongata.
Caste‐specific patterns of flower visitation in bumble bees (Bombus kirbyellus) collecting nectar from Polemonium viscosum
Authors: GALEN CANDACE , BLAU SHERI
Published: March 2008

ABSTRACT.

Foraging routes of worker and queen bumble bees (Bombus kirbyellus Curtis) collecting nectar from flowers of the alpine sky pilot, Polemonium viscosum Nutt., were followed and the corolla tube length, corolla diameter, floral scent, and number of flowers on plants visited or bypassed by bees were monitored. Additionally, the number and proportion of flowers visited per inflorescence and distance flown from each to the next were recorded. Queens and workers differed significantly in choice of flowers. However, intra‐inflorescence visitation rates and departure distances were similar between castes. Castes differed in the extent to which visitation reflected patch quality versus individual floral traits.

Both queens and workers failed to visit skunky‐flowered plants more often than they failed to visit sweet‐flowered ones, and preferred large over small inflorescences. However, queens visited large‐flowered plants more often than small‐flowered ones, while workers preferred flowers with shorter corolla tubes, regardless of their diameter. Although a number of studies have documented caste specialization on alternate species of host plants, ours is one of the first to show that morphological preferences promote comparable foraging differences between castes on monospecific plant resources.

Queens, once on a plant, responded to floral traits by probing more flowers on large inflorescences, as well as on those with broader floral form. Workers did not alter intra‐inflorescence visitation rate in response to floral traits.

For workers, no significant relationship was demonstrated between the likelihood of passing by a plant and the number of flowers probed on the previous inflorescence visited. Thus, workers appeared to accept or reject each plant of P. viscosum independently. However, queens passed by fewer plants when leaving rich inflorescences than poor ones. These results suggest that workers use only individual plant acceptability in choosing which plants to visit, whereas queens base plant choice on patch and individual attributes. Such differences between castes in foraging rules when exploiting the same floral resource have received little attention, and provide insights into the heterogeneity of harvestable reward distributions from the perspective of the forager population.
Species number, species abundance and body length relationships of arboreal beetles in Bornean lowland rain forest trees
Authors: MORSE D. R. , STORK N. E. , LAWTON J. H.
Published: March 2008

ABSTRACT.

The relationships between number of species, abundance per species, and body length are examined for 859 species of beetles in samples of arthropods collected from ten Bornean lowland forest trees by insecticide fogging. Similar relationships are examined for different feeding guilds of these beetles, and for those beetles from different species of trees.

The data are used to construct four interrelated graphs, namely species: abundance, species: body length, population abundance: body length and total number of individuals: body length distributions.

In contrast to a number of previous studies, no consistent linear relationship between population density and body length was found for the Bornean beetles and it is suggested that, as in birds, the added dispersal ability of flight reduces critical population densities necessary for persistence in small species. Previous relationships between body weight and population abundance may also be artefacts of the way in which data were gathered.

Despite large samples, we failed to locate the mode in plots of the number of species in each abundance category (species: abundance distribution).

Species: body length and total number of individuals: body length plots were similar to those found in previous studies, although using data for Coleoptera alone may have produced a steeper decline in the total number of individuals as body size increases than is apparent in samples of all arthropods.

We present the first three‐dimensional graph relating numbers of species, body lengths and population abundances. The surface of this three‐dimensional relationship is relatively simple.
Abundance and mortality of leaf miners on artificially shaded Emory oak
Authors: BULTMAN THOMAS L. , FAETH STANLEY H.
Published: March 2008

ABSTRACT.

We measured solar radiation reaching ten Quercus emoryi Torr. trees and recorded densities of four leaf‐mining insect species on these trees from June until September 1982.

The measurements showed that densities of two leaf miner species were negatively correlated with solar radiation.

In a field experiment, polypropylene shade fabric was suspended 1.3 m above four experimental trees to test for effects of reduced sunlight.

Leaves of experimentally‐shaded trees were heavier and contained lower percentages of proteins and gallotannins than leaves of control, sun trees, while per cent foliar monomeric, polymeric, and total phenols, and water content did not differ between sun and shaded trees.

Two of four leaf miner species had greater densities on experimentally‐shaded trees than sun trees. One of these two species experienced lower survivorship on sun trees owing to high levels of death from unknown causes on sun trees.

Two leaf miner species had greater densities on sun trees. One of these species had higher survivorship on shaded trees owing to high levels of parasitism on sun trees.

We conclude that even subtle differences in shading influences leaf miner density and mortality; however, the effects of shading vary from positive to negative among leaf miner species.
Hunger, partial consumption of prey and prey size preference in a carabid beetle
Authors: ERNSTING G. , VAN DER WERF D. C.
Published: March 2008

ABSTRACT.

Partial consumption of prey and prey size preference were studied in females of the carabid Notiophilus biguttatus F., using different size‐classes of the springtail Orchesella cincta (L.) as prey.

Time to ingest a prey increases disproportionately with prey size, mainly as a consequence of satiation.

During consumption of a prey the predator's rate of ingestion decreases, partly because of diminishing returns from the prey over feeding time.

The hypothesis that the diminishing returns from the prey induce partial consumption was refuted.

Partial consumption in the beetle is due to gut limitation; its occurrence depends on prey size.

Average weight of prey remains in four prey size classes were close to weights expected from average intercatch intervals and estimates of hunger.

Prey choice depends on level of food deprivation.

Partial consumption of prey, prey size preference and profitability of prey in relation to hunger of the beetle are discussed.
Dung burial strategies in some South African coprine and onitine dung beetles (Scarabaeidae: Scarabaeinae)
Authors: DOUBE B. M. , GILLER P. S. , CSIRO F. MOOLA
Published: March 2008

ABSTRACT.

The dung colonization and dung burial behaviour of twelve crepuscular/nocturnal tunnelling (paracoprid) species of beetles were examined in order to identify mechanisms which might facilitate resource (dung) partitioning. The species were selected from a diverse assemblage of dung beetles, the members of which coexist in the sandy‐soil regions of Natal, South Africa.

The pattern of dung colonization in relation to dung age was examined in the field using baited pitfall traps. Some species, e.g. Onitis deceptor Peringuey, Catharsius tricornutus De Geer and Copris elphenor Klug, showed a marked preference for fresh dung (1–2 days old) whereas other species, e.g. O. viridulus Boheman and Copris fallaciosus Gillet, preferred older dung (3–7 days old).

Two distinct patterns of dung burial were recognized. In the Coprini, dung burial was complete within 24–48h of pad colonization, and the level of dung burial was similar in the laboratory and in the field. In the Onitini, dung burial occurred progressively over a 12‐day period, although the timing of initiation of dung burial varied between species: in O. deceptor nearly all individuals had begun burial within 2 days of pad colonization, whereas only 20% of O. viridulus had commenced dung burial by that time. However, nearly all O. viridulus had buried substantial quantities of dung by day 12.

The mass of dung buried per pair by the larger coprine beetles (100–300 g) and onitine beetles (400–1000 g) suggests that there is potential for inter‐ and intraspecific competition, even in pads colonized by relatively few beetles. The colonization and use of dung of different ages are discussed as means of resource partitioning in relation to the relative abilities of species to compete for dung.
Delayed ovarian maturation in the butterfly Hipparchia semele as a possible response to summer drought
Authors: GARCÍA‐BARROS E.
Published: March 2008

ABSTRACT.

Several references indicate that the period of flight of the European satyrine butterfly Hipparchia semele (L.) (Nymphalidae, Satyrinae) starts earlier in southern latitudes, where summers are longer and drier than in the north. However, summer drought has an adverse effect on the growth of grasses on which larval feeding depends. Growth of the grasses is delayed as long as the drought lasts.

From laboratory and field observations in a mid altitude area near the centre of the Iberian Peninsula, a mechanism that can be interpreted as an adjustment of this insect's life cycle to the host plant's phenology has been observed, i.e. delayed gonadal maturation of adult females. This delay is not associated with female diapause. Although the mean delay in oviposition after copulation was 43 days some captive females were able to oviposit much earlier, and this suggests variability in oviposition dates which might have an environmental or a genetic basis.

A mechanism of delayed ovarian maturation similar to that of H.semele is also known to occur in the satyrine Maniola jurtina (L.); it is suggested that this adaptation enables these species to occupy wider geographical ranges than other univoltine satyrines in Europe.
Parasitic flies (Conopidae, Diptera) may be important stress factors for the ergonomics of their bumblebee hosts
Authors: SCHMID‐HEMPEL PAUL , SCHMID‐HEMPEL REGULA
Published: March 2008

Bumblebees harbour a wide range of parasitic organisms that attack all stages of their life cycles (reviews in Postner, 1951; Pouvreau, 1973, 1974; Alford, 1975; Kistner, 1982). Among them, conopid flies (Conopidae, Diptera) are particularly interesting because they attack foraging bumblebees which are handling flowers, or even on the wing (Frison, 1926; Cumber, 1949; Postner, 1951; Howell, 1967; Askew, 1971). A single egg is attached to (Frison, 1926; Plath, 1934; Cumber, 1949) or inserted into (DeMeijre, 1904; Howell, 1967) the host's abdomen, where the larva hatches and feeds on haemolymph and internal organs. Within 6–10 days the larva passes through three recognizable stages (Pouvreau, 1974) before the fly pupates in situ within the abdomen. The host bee dies shortly before the parasite pupates (Postner, 1951; Smith, 1966) and the parasite overwinters in its puparium; the adult fly then emerges in early summer (Frison, 1926; Townsend, 1935; Cumber, 1949; Postner, 1951). Conopid flies as parasites of bumblebees are known from all major habitats where the hosts occur (e.g. Kröber, 1939; Smith, 1966). However, the effect of parasitism on distribution and abundance of bumblebees is not known. In this preliminary note we have estimated degrees of infestation and concomitant reduction of life span in affected workers. The results are compared with literature reports on infestation levels in Europe.
The photoperiodic responses and phenology of an English strain of the pea aphid Acyrthosiphon pisum
Authors: LEES A. D.
Published: March 2008

Abstract. 1. The response curves for the photoperiodic induction of the sexual forms (oviparae and males) differ significantly in an English clone of the pea aphid Acyrthosiphon pisum Harris. Male production is sharply peaked. The late summer scotophases (dark periods) that initiate male production are 1.0–1.5 h shorter than those that initiate ovipara production; the induction of males, but not oviparae, virtually ceases at scotophases longer than 12 h. This disparity suggests that there are two photoperiodic clocks.

2. All ovipara‐producing aphids switch spontaneously to virginopara production part‐way through the progeny sequence, irrespective of photoperiod. This may confer the ability to overwinter partheno‐genetically under favourable climatic conditions. Since males are always born last in the progeny sequence this possibility would be pre‐empted unless the terminal male sequences were suppressed by long winter scotophases.

3. The role of the photoperiodic response in determining the seasonal phenology was tested in the field by exposing a succession of laboratory‐reared aphids to natural photoperiods, in late summer and autumn. Adult males and oviparae developed synchronously in early October, the difference in critical scotophase compensating for the late appearance of males in the progeny sequence. A large part of the ‘civil twilight’ is photoperiodically active.

4. Clones propagated outdoors by isolating aphids in each generation from the terminal sequence of virginoparae did not survive the whole winter of 1985/86. The chances of survival were reduced by severe weather and by the inability of the photoperiodic system to ‘turn off’ the production of early born oviparae which are, therefore, ‘wasted’.