bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors underlying the late seasonal appearance of the lepidopterous leaf‐mining guild on oak
Authors: WEST C. 
Published: March 2008

Abstract. 1. Most lepidopterous leaf mining species found on the oak Quercus robur in Britain develop in summer. At this time of year, externally feeding caterpillars remove little leaf area since most of these free living folivores are predominantly spring feeders.2. I forced Phyllonorycter harrisella (L.) miners to oviposit in spring, then exposed developing larvae to a wide range of leaf damage levels.3. Leaf miner survivorship and mean female pupal weight were significantly greater in the experimental spring generation on undamaged oak leaves, this being when oak foliage is of the highest nutritional quality.4. Leaf miner survivorship in all generations is correlated with natural leaf damage levels. Experimental leaf damage also reduces miner survivorship.5. Leaf damage reduces miner survivorship by increasing the probability of larval death due to wound induced responses.6. The role of asymmetrical competitive interactions between caterpillars and leaf‐miners in determining the late seasonal appearance of miners is discussed. It is suggested that wound induced responses may play an important part in the structuring of phytophagous insect communities.
Patterns of intra‐ and interspecific association in leaf‐mining insects on three oak host species
Authors: BULTMAN THOMAS L. , FAETH STANLEY H. 
Published: March 2008

Abstract. 1. We determined mortality and distributional patterns of leaf miners on three oak host species (Quercus falcata, Q.nigra and Q.hemisphaerica) in northern Florida, U.S.A.2. Patterns of intra‐ and interspecific occurrence within leaves, and mortality of five most abundant leaf miner species were analysed as a test of competition.3. Miners co‐occurred on leaves more often that expected by chance (P<0.05) in six of ten possible species combinations and log‐linear model analysis showed no negative higher‐order interactions.4. All five miner species had highly clumped distributions between leaves (P<0.01).5. Leaf miner survival was less than expected for four of five species when co‐occurring on leaves with conspecifics than when mining with heterospecifics or alone (P<0.05).6. We conclude that interspecific competition is unapparent within this leaf miner guild and that intraspecific competition occurs in four of the five major leaf miner species. We discuss leaf miner selection of common leaves, perhaps based on chemical/physical leaf characters, as a cause of intra‐ and interspecific aggregation.
The foraging ecology of the army ant Eciton rapax: an ergonomic enigma?
Authors: BURTON JAMES L. , FRANKS NIGEL R. 
Published: March 2008

Abstract. 1. The army ant Eciton rapax (F. Smith) produces longer raid systems than any other member of its genus and it is a specialist predator of forest floor and understory ants such as species of Camponotus, Odontomachus and Pachycondyla.2. Allometrical analysis confirms that E. rapax is the only member of its genus without distinct physical castes among its workers: its foraging population is entirely monomorphic and there are no majors.3. The workers of E. rapax are distributed over a considerable size range, and there are distinct divisions of labour within these colonies: small workers tend to stay in the nests and among the larger foraging workers those retrieving prey items are significantly bigger than the rest.4. An analysis of foraging efficiency and worker performance in E. rapax suggests that transport costs, resulting from the great distances that workers travel during raids and emigrations, are one of the selection pressures that have favoured the evolution of large monomorphic workers in this species.
Foraging by the carabid Agonum dorsale in the field
Authors: GRIFFITHS E. , WRATTEN S. D. , VICKERMAN G. P. 
Published: March 2008

Abstract. 1. Small arenas in the field were used for observing adult Agonum dorsale (Pont.) foraging in a wheat crop.2. The carabid showed no significant change in behaviour between low and high aphid density arenas.3. Individuals foraged nocturnally and spent most of their time on the ground searching for prey. They climbed infrequently and then not high enough to reach aphid aggregations on the ears and flag leaves of wheat.4. Gut dissection showed that more individuals had eaten aphids in the high aphid density arena than the low. Recording of aphid distribution within the arenas showed that this increase in aphid consumption could be explained by A.dorsale capturing aphids on the ground. Prey availability per unit area was in fact higher on the ground than on the wheat.5. The contribution of ground‐zone predators such as A.dorsale to the control of cereal aphids will be determined by the frequency with which aphids arrive on the ground and the proportion of these which reclimb the wheat and reproduce in the absence of predation.
Insect visitors to extrafloral nectaries of Byttneria aculeata (Sterculiaceae): relative importance and roles
Authors: HESPENHEIDE HENRY A. 
Published: March 2008

Abstract. 1. Ants, parasitoids and flies are about equally frequent at foliar nectaries of Byttneria aculeata (Sterculiaceae) in lowland Costa Rica during the dry season, a pattern previously unreported but also observed at other plants in the area.2. Species of Ectatomma, Crematogaster and Camponotus were the most frequent of twenty‐four ant species on Byttneria, eight of which nested in the hollow stems. Ants spent most time at nectaries and little in patrolling.3. Collections at nectaries yielded large numbers of species of parasitoid Hymenoptera with few individuals of each. Rearing studies of leaf‐feeding herbivores yielded several species of parasitoids, including one species taken at a nectary and two others congeneric or closely related.4. Flies appear to be nectar thieves, in the same sense as non‐pollinating floral visitors, despite close association with Byttneria.5. Ant‐plants may be poor models for the larger number of species of less specialized plants with extrafloral nectaries. Plants which have only extrafloral nectaries may better suit the needs of parasitoids than ants, and plants such as Byttneria may benefit as much from parasitoids as from ants.
Determining the age of adult male and female Glossina morsitans morsitans using a new technique
Authors: LEHANE M. J. , MAIL T. S. 
Published: March 2008

Abstract. 1. Pteridines accumulated linearly with age up to at least 63 days in male and 140 days in female Glossina morsitans morsitans Westwood kept under laboratory conditions. Time is the major factor influencing total pteridine accumulation levels with the accumulation rate being modulated by temperature.2. It is suggested that pteridine accumulation may be used to determine the age of male and female tsetse flies in the field.
Ability of ovipositing seed beetles to discriminate between seeds with differing egg loads
Authors: MESSINA FRANK J. , RENWICK J. A. A. 
Published: March 2008

Abstract. 1. Previous work has shown that ovipositing females of Callosobruchus maculatus (F.) avoid seeds already bearing eggs, and thereby reduce competition among their larval progeny within seeds.2. This study demonstrates that females also detect small differences in egg density, and prefer to oviposit on seeds with a lower‐than‐average number of eggs. A nearly uniform dispersion of eggs is thus maintained even after all seeds bear several eggs.3. In addition, variation in egg load influences oviposition rate. Transfer of females from seeds with few eggs to seeds with many eggs inhibits oviposition; the reverse transfer stimulates it.4. The upper surface of the egg chorion or egg ‘cover’ remains intact on the seed surface after the larva has entered the seed and continues to deter egg‐laying for at least as long as the period required for larval development. 14‐day‐old egg covers provide as much deterrence as freshly laid eggs.
The relationship between size and reproductive potential in male and female Epirrita autumnata (Lep., Geometridae)
Authors: HAUKIOJA ERKKI , NEUVONEN SEPPO 
Published: March 2008

Abstract. 1. We studied the fecundity of Epirrita autumnata Bkh. (Lepidoptera) in relation to pupal weight of females and males.2. There was no clear correlation between male size and the success in fertilization over a considerable range of weights (from 50 mg to over 100 mg) although in one experiment only large males were successful in multiple fertilizations.3. In the three experiments where small males (<50 mg) were used they showed reduced performance, and a large proportion of them was sterile.4. Unlike in males, the number of eggs laid by females correlated linearly with pupal weight over the whole range of female weights.
Activity patterns, diets and interspecific interactions of coexisting spring and autumn breeding carabids: Carabusyaconinus and Leptocarabus kumagaii (Coleoptera, Carabidae)
Authors: SOTA TEIJI 
Published: March 2008

Abstract. 1. Activity patterns, diets and interspecific interactions of two coexisting carabid beetles, Carabus yaconinus B. and Leptocarabus kumagaii K. et K., were studied in a lowland habitat in Japan.2. Larvae of C. yaconinus appeared from May to October and fed on earthworms. Those of L. kumagaii appeared from October to the next May and fed on dipteran and lepidopteran larvae.3. In the adult stages, feeding habits and daily activities of the two species were similar. The beetles fed mainly on earthworms and other animal materials, but various plant materials were also utilized.4. Direct competition for food items was observed both intra‐ and interspecifically. Interspecific interactions occurred only in early summer, however, because of the difference in breeding seasons (i.e. spring for C. yaconinus and autumn for L. kumagaii).5. The difference in seasonal life history patterns between these carabids is a possible mechanism of coexistence.
Host gall size and oviposition success by the parasitoid Eurytoma gigantea
Authors: WEIS ARTHUR E. , ABRAHAMSON WARREN G. , McCREA KENNETH D. 
Published: March 2008

Abstract. 1. Eurytoma gigantea Walsh is a specialist parasitoid of the tephritid gallmaker Eurosta solidaginis (Fitch).2. In the natural environment the incidence of parasitism by Eurytoma is greater in small galls than in large ones.3. Laboratory experiments demonstrated that small galls are not more frequently discovered; however, oviposition attempts on small galls were more likely to be successful.4. Eurytoma spends much time probing galls too big to penetrate; this leads to a decrease in foraging efficiency when many large galls are present.5. The chance of successfully penetrating a gall depends on the thickness of the gall wall and the length of the parasitoid's ovipositor.6. A simulation model was constructed which shows that a gallmak‐er's chance of being parasitized depends on gall size, the number of parasitoids that discover the gall, and their ovipositor lengths.
Diurnal activity patterns in hoverflies (Diptera, Syrphidae)
Authors: GILBERT FRANCIS S. 
Published: March 2008

Abstract. 1. Time‐budgets are constructed from censuses of hoverflies. Larger species spend less time in flight.2. Most species are active under similar conditions of light intensity, but a shade‐tolerant (Melanostoma scalare Fabr.) and a sun‐loving species (Metasyrphus corollae Fabr.) were identified.3. Large species become active (i.e. move, by flying or feeding) at lower temperatures than small ones, except M.scalare, which is tolerant to cool temperatures. This means that, M.scalare apart, the order of species appearing during the day is size‐dependent, largest first.4. Previous claims about the diel periodicity of syrphids can be reconciled by considering the importance of individual thermal balance.5. Tolerance to low temperatures in small hoverflies is associated with feeding on anemophilous pollen; this may indicate a proline‐fuelled flight.
The predatory Chironomidae of an iron‐rich stream: feeding ecology and food web structure
Authors: HILDREW ALAN G. , TOWNSEND COLIN R. , HASHAM AZIM 
Published: March 2008

Abstract. 1. Three species of Tanypodinae (Chironomidae) were found in an acid and iron‐rich stream in southern England. Maximum abundance was achieved in summer and they were sparse at other times. Individuals were aggregated on the stream bed and were overrepresented in accumulations of leaf litter.2. The diets of all three species consisted of a mixture of prey (prominently detritivorous chironomid larvae) and detritus. More detritus and fewer prey were taken in winter than in summer.3. When comparing large tanypod species with small and, intraspecifically, late instars with early, the proportion of guts containing prey increased with increasing body size.4. Stonefly larvae were more prominent in the diet of Zavrelimyia barbatipes (Kieffer) in summer than in winter but for the other two species the reverse was true. A bigger proportion of Trissopelopia longimana (Staeger) guts contained prey in early summer than in August whereas more Macropelopia goetghebueri (Kieffer) guts contained prey in August. This was apparently a consequence of seasonal differences in the distribution of body size among the populations of these two species.5. The stream contains two further common predators, Plectrocnemia conspersa (Curtis) and Sialis fuliginosa Pict. These are important predators of tanypod larvae but might also compete with them since they severely deplete populations of prey taken in common.6. Analysis of the food‐web in Broadstone Stream reveals remarkably high values of connectance (C and Cmax) and of species richness times connectance (SCmax). Such characteristics are theoretically associated with fragile and dynamically unstable food webs, and may be found in ‘constant’ environments. There is also an apparently unusual prevalence of omnivory in the community.
Mechanical limitations on feeding by meadow spittlebugs Philaenus spumarius (Homoptera: Cercopidae) on wild and cultivated host plants
Authors: HOFFMAN GEORGED. , McEVOY PETER B. 
Published: March 2008

Abstract. 1. Field observations on the distribution of Philaenus spumarius (L.) on pearly everlasting (Anaphalis margaritacea) and alfalfa (Medicago sativa) showed that the range of feeding sites exploited increased with instar. Development of trichomes, depth of xylem elements, and tissue hardness were measured as possible factors determining the suitability of sites on food plants.2. Spittlebugs caged outside their normal feeding sites experienced difficulty feeding. Experimental removal of trichomes showed that trichomes prevented younger instars from feeding on the stem. The depth of the xylem elements and tissue hardness were not significant barriers to feeding near the stem apex.3. By caging fourth and fifth instar nymphs at increasing distances below the terminal bud on A.margaritacea stems, we showed feeding ability declined with distance below the apex, and feeding was more restricted in fourth compared to fifth instars. A similar decline was demonstrated in experiments with fifth instars on M.sativa.4. On A.margaritacea, this restriction was associated with increasing tissue hardness of the stem with distance from the apex and the presence of trichomes in regions with hard tissues. On M.sativa the associated barriers were a combination of tissue hardness and reduction in the availability of xylem vessels in the penetrable region of the stem. Although the tissues impeding stylet penetration differed in the two hosts, the critical factor in both species was the increase in the amount of lignification of those tissues at increasing distances from the terminal bud.
An association between two species of pine aphid, Schizolachnus pineti and Eulachnus agilis
Authors: KIDD N. A. C. , LEWIS G. B. , HOWELL C. A. 
Published: March 2008

Abstract. 1. Two aphid species feed exclusively on pine needles, Schizolachnus pineti (Fabr.) occupying only the outer (curved) surface with Eulachnus agilis (Kalt.) showing a preference for the inner (flat) surface.2. Despite E.agilis favouring and S.pineti avoiding senescing needles, both species show a significant tendency to share shoots and needles in the field.3. The same association is also apparent under laboratory conditions, although E.agilis is randomly distributed between needles in the absence of S.pineti.4. E.agilis was found to benefit through increased survival and faster growth rates, by feeding on the same shoots and needles as S.pineti.5. It is suggested that E.agilis may be able to detect and exploit an improvement in the nutritive quality of needles brought about by the feeding activity of S.pineti colonies.
Aggregation and mating of thrips in flowers of Calystegia sepium
Authors: KIRK WILLIAM D. J. 
Published: March 2008

Abstract. 1. Aggregation and mating of Thrips major Uzel and Thrips fuscipennis Haliday (Thysanoptera: Thripidae) in the 1‐day flowers of Calystegia sepium (L.) R.Br. are described.2. The number of thrips per flower increased rapidly after flower‐opening at dawn and decreased during the evening and following morning.3. Males patrolled the corolla, attempting to copulate with any females that landed. Their movement was affected by the density of thrips on the corolla. Most females were among the stamens and style, apparently feeding on pollen.4. These thrips were also abundant in flowers of Filipendula ulmaria (L.) Maxim. They fed on pollen, and grains adhered to them. They may be significant pollinators because of their high frequency of flights.5. The aggregations appear to be a simple consequence of general flower‐finding responses to colour and scent that are particularly elicited by flowers of C.sepium and F.ulmaria. The ecological significance of male aggregations is discussed.
Size effects on the hygrothermal balance and foraging patterns of a sphecid wasp, Cerceris arenaria
Authors: WILLMER P. G. 
Published: March 2008

Abstract. 1. Cerceris arenaria (L.) females nest in sandy burrows, foraging for prey weevils to stock cells in which eggs are laid. Nests are easily distinguished and observed, and tunnel diameter correlates well with the occupying females' size (range 68–128 mg).2. Foraging depends on ambient temperature and occurs only during periods of insolation. Large females can forage earlier in the day, and usually make a greater number of successful trips per day, than smaller ones.3. Size differences of females affect heat exchange and resultant temperature excesses (Tex). At the highest ambient temperatures Tex for the largest wasps can exceed physiological tolerances, thus reducing foraging activity relative to the smaller females.4. On very hot days wasps forage more frequently for nectar, probably to reduce their water deficits. Larval water balance is controlled less directly, by the architecture of burrows and the nature of cell walls and contents.5. Temperature effects on foraging and nesting bring about a roughly two‐fold increase in success as cell provisioners (and hence egg‐layers) of larger over smaller females. Possible countering effects of very hot weather and of parasitism, either of which might favour small females in some conditions, are discussed.
Changes in life‐cycle strategies of Carabus problematicus over a range of altitudes in Northern England
Authors: BUTTERFIELD J. E. L. 
Published: March 2008

ABSTRACT.

Mandible tip length has been used to estimate the age of individual C.problematicus Herbst caught over an altitude range of more than 700 m in northern England.
At 100 m the great majority of females laid eggs in the summer of their emergence as adults. The female life‐cycle is predominantly annual and 24% only of the egg‐bearing individuals were in their second year.
Above 250 m, most females did not reproduce until the summer of the year following emergence, giving a biennial life‐cycle. 96% of egg‐bearing females caught above 830 m were in their second year.
All the males caught during the breeding season at 100 m had emerged within that calendar year and it is concluded that the male life‐cycle is annual at this altitude.
Above 250 m, 83% of the males caught during the breeding season were in their first calendar year, suggesting that recently emerged males may inseminate second year females and also that the male life‐cycle is predominantly annual over the whole altitude range studied.
At the higher temperatures of the lowland site females not only produce eggs in the year of emergence, they also produce more eggs per individual than at the higher sites. Egg production depends on food intake which involves mandible wear and individuals at the lowland site have significantly higher rate of mandible wear than at the sites above 250 m.
Alarm‐recruitment behaviour in Pheidole militicida (Hymenoptera: Formicidae)
Authors: FEENER DONALD H. 
Published: March 2008

ABSTRACT.

Pheidole militicida Wheeler, a seed‐harvesting species of the southwestern United States, possesses a major worker caste (soldiers) with unusually large heads. Previous work suggested that these large major workers are specialized defenders against large seed‐harvesting species in the genus Pogonomyrmex.
Experimental introductions of Pogonomyrmex maricopa Wheeler and the omnivorous fire ant, Solenopsis xyloni McCook, demonstrate that P. militicida colonies alarm‐recruit major workers against S.xyloni workers but not against the larger Pogonomyrmex workers.
P.militicida is the second species in which enemy‐specific defence against Solenopsis fire ants has been detected. I suggest that the special role of Solenopsis as both competitor and predator in ant communities frequently favours major worker specialization against this genus.
Major workers of P.militicida and Pheidole dentata Mayr, the other species with enemy‐specific defence against Solenopsis, are morphologically very different from one another. It is suggested that interspecific variation in major worker morphology is not necessarily associated with variation in behavioural specialization.
The effects of foraging ants on arboreal insect herbivores in an undisturbed woodland savanna
Authors: GRANT S. , MORAN V. C. 
Published: March 2008

ABSTRACT.

A comparison was made of the insect fauna on paired Terminalia sericea, Burkea africana and Ochna pulchra trees; one tree in each pair was treated with Formex® to exclude ants from the canopy, and the other was designated the control.
Treatment with Formex banding to exclude ants did not influence plant phenology.
Pyrethrum knockdown samples from control trees had generally more insect individuals and insect species than samples from trees where ants were excluded.
Formex‐treated trees had significantly less homopterous individuals and species than the control trees.
With the exception of ants and Homoptera, there was no difference in the insect guild composition and dominance ranking of various insect taxa, sampled by pyrethrum knockdown, between the control and Formex‐treated trees.
T.sericea had significantly greater populations of both sessile and mobile Homoptera on the control trees than on the Formex‐treated trees. A similar trend could be seen on B.africana. There were significantly more sessile homopterans on the control trees of O.pulchra than on the Formex‐treated trees. Low numbers of mobile Homoptera were recorded on both control and Formex‐treated O.pulchra trees, and numbers on control trees were fewer in comparison to numbers of mobile Homoptera on control T.sericea and B.africana trees.
It is concluded that the ants have similar effects on the insect communities of trees in a natural, undisturbed savanna as has been demonstrated on trees in agro‐ecosystems, and on plants that are structurally adapted for mutualistic associations with ants.
Although slight, leaf damage by some leaf‐feeding insects was greater on trees where ants had been excluded than on control trees that supported foraging ant populations.