bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climatic adaptations in the Drosophila immigrans species group: seasonal migration and thermal tolerance
Authors: KIMURA MASAHITO T. , BEPPU KATSURA 
Published: March 2008

Abstract. 1. In central Japan, Drosophila curviceps Okada and Kurokawa was collected in spring and autumn but not in summer at lowlands (alt. 500–1200 m), while it was collected only in summer at highlands (1500–2000 m). Experiments on its thermal tolerance suggested that summer heat at the lowlands and winter low temperatures at the highlands were adverse to this species. It is considered that this species escapes from these extreme temperatures by undergoing seasonal migration between the lowlands and the highlands. This species had no photo‐periodic diapause and bred at both lowlands and highlands.2. D.immigrans Sturtevant was less cold‐hardy but more heat‐tolerant than D.curviceps. It is considered that this species is unable to overwinter outdoors at least in the study areas (i.e. alt. 500m or higher in central Japan) and its populations in these areas originate with migrants from warmer areas.3. D.albomicans Duda, a subtropical species, was less cold‐hardy but more heat‐tolerant than the above two species.4. Climatic adaptations and distributions of these species are discussed with reference to their thermal tolerance.
The influence of Salix leaf abscission on leaf‐miner survival and life history
Authors: PRESZLER RALPH W. , PRICE PETER W. 
Published: March 2008

Abstract. 1. Early abscission of mined leaves was an important mortality factor of a Phyllonorycter species (Lepidoptera: Gracillariidae) on Salix lasiolepis Benth. (Salicaceae). A larger percentage of mined leaves abscised early (34.4% in 1990; 24.5% in 1991), and Phyllonorycter survival was greatly reduced in these abscised leaves.2. Leaf‐mining by Phyllonorycter was associated with increased early leaf abscission. An egg removal experiment demonstrated that leaf mining induced this increase in leaf abscission.3. The induction of early leaf abscission was dependent upon the timing of herbivory and simulated herbivory (mechanical damage). Early mechanical damage induced leaf abscission, late mechanical damage did not. Mines which expanded early were more likely to induce leaf abscission than mines which expanded more slowly.
Resource limitation and the lethal and sublethal effects of a viral pathogen in the Indian meal moth, Plodia interpunctella
Authors: BOOTS MICHAEL , BEGON MICHAEL 
Published: March 2008

Abstract.

The effects of resource limitation and the lethal and sublethal effects of a granulosis virus on a lepidopteran host, the Indian meal moth, Plodia interpunctella, were examined.
The food quality was manipulated by the addition of an inert bulking agent (methyl cellulose) which caused the size, development rate and fecundity of the moths to be reduced.
The resource quality had no effect on the mortality due to the virus. In contrast, sublethal effects of the virus on pupal weight were more apparent under conditions of resource limitation.
Considerable variation between the sublethal effects after challenge with different doses of the virus was found. The balance between deleterious sublethal effects of the virus and the selection of more robust individuals by the bioassays is proposed as a mechanism to explain this variation.
Implications for the dynamics of insect hosts and their pathogens are discussed.
Density‐related foraging behaviour in Closterocerus tricinctus, a parasitoid of the leaf‐mining moth, Cameraria hamadryadella
Authors: CONNOR EDWARD F. , CARGAIN MICHELE J. 
Published: March 2008

Summary

We examined the foraging behaviour of the parasitoid wasp, Closterocerus tricinctus (Ashmead) (Chalcidoidea: Eulophidae), as it visited larvae of the leaf‐mining moth, Cameraria hamadryadella (Lepidoptera: Gracillariidae), in an outbreak population.
We tracked females of C.tricinctus, recording the time spent searching for mines and handling host larvae. The density of leaf‐mines (host larvae) and their condition were recorded for each leaf visited. A subset of leaves visited by C.tricinctus was enclosed in fine mesh bags so that foraging success could be determined by rearing or dissection. The average density of mines and the average leaf‐area mined was estimated for a random sample of leaves from each tree.
The selection of leaves upon which to forage appears to be density‐dependent. C.tricinctus visits leaves with leaf‐mine densities twice the average, and when switching leaves lands directly on leaf‐mines 5 times more often than expected assuming random landings.
The total time spent foraging on a leaf, the average time spent handling hosts, and the total search time within leaves tend to decline on leaves with many hosts, but the observed declines are not statistically significant.
The proportion of leaf‐mines visited within a leaf is strongly inversely density‐dependent. 30% of visits to leaf‐mines are re‐visits and 29% of handling time is spent re‐handling previously visited hosts. Furthermore, only 21% of visits to mines lead to successful parasitism. We suggest that self‐interference and the avoidance behaviour of the host may reduce the number of visits of leaf‐mines by C.tricinctus within a leaf.
The effect of the strongly inversely density‐dependent foraging investment within leaves is to offset the observed density‐dependent pattern of leaf visitation making the overall spatial pattern of visitation by C.tricinctus to mines of C.hamadryadella inversely density‐dependent.
We suggest that the uncertainty of C.tricinctus surviving on multiply mined leaves because of density‐dependent host mortality due to intraspecific competition in high‐density host populations, the rarity of high‐density host populations, and the rarity of multiply‐mined leaves in low‐density host populations combine to select against an aggregative response within leaves by C.tricinctus.
Defence and development in a gregarious leaf‐mining beetle
Authors: DAMMAN HANS 
Published: March 2008

Abstract.

The gregarious larvae of the chrysomelid beetle Microrhopala vittata mine the leaves of goldenrods (Solidago spp.). These mines serve both as food and as shelter for the larvae.
Life‐table data and experiments indicated that mine initiation and moves to secondary mines represented especially vulnerable stages during larval development. Leaf mines effectively protected M.vittata against predators in the field.
Field experiments indicated that larvae hatching from larger clutches of eggs stood a greater chance of surviving to pupation, primarily because larvae hatching in groups proved more successful at initiating leaf mines. Once inside the leaf mine, however, larvae feeding in large groups attained lower adult masses, and were more likely to abandon the natal mine and did so earlier in development because large groups more rapidly destroyed a leaf.
Root disturbance of common ash, Fraxinus excelsior (Oleaceae), leads to reduced foliar toughness and increased feeding by a folivorous weevil, Stereonychus fraxini (Coleoptera, Curculionidae)
Authors: FOGGO ANDREW , SPEIGHT MARTIN R. , GRÉGOIRE JEAN‐CLAUDE 
Published: March 2008

Abstract.

Bioassays were carried out to examine differences in the feeding of a folivorous weevil, Stereonychus fraxini De Geer, on leaves from ash saplings with undamaged roots, and those with damaged roots. Beetles ate significantly more of the leaves of root‐damaged saplings in a choice experiment.
A separate study of the effect of root damage on leaf toughness was carried out on a second group of ash saplings. Saplings with damaged roots had less tough leaves than control saplings. Decreased leaf toughness in hypothesized as a mechanism to explain the preference of weevils for leaves from damaged trees.
Both chemical and physical changes may occur in the tissues of ash trees in response to environmental stress such as drought and root damage.
Root damage caused by agricultural disturbance is hypothesized as a mechanism making mature ash trees in hedgerow ecosystems more susceptible to insect herbivores.
Patch‐leaving rules for parasitoids with imperfect host discrimination
Authors: ROSENHEIM JAY A. , MANGEL MARC 
Published: March 2008

Abstract.

The solitary parasitoid Anagrus delicatus attacks hosts (plant‐hopper eggs) that exist in distinct batches and that are readily detectable to the foraging parasitoid. However, Anagrus delicatus attacks only a small fraction of the available hosts within a batch of eggs and then disperses (Cronin & Strong, 1993a). Here we address the question: Why is A.delicatus abandoning seemingly high quality patches?
A parasitoid with an imperfect ability to discriminate between unparasitized hosts and hosts that it has attacked earlier within the same patch experiences a risk of self‐superparasitism when attacking multiple hosts within a single patch. Self‐superparasitism can incur costs in the form of lost time and eggs. Early patch leaving can be favoured as a means of avoiding the costs of self‐superparasitism.
A simple static model demonstrates that patch leaving is favoured by low costs of travelling to a new patch, high error rates in discriminating previously self‐parasitized hosts, and high levels of parasitism in the currently occupied patch.
A more detailed dynamic state variable model, parameterized for A.delicatus, demonstrates that this parasitoid's seemingly enigmatic behaviour can be explained under our hypothesis. In order for this to be the case, we predicted that A.delicatus cannot recognize previously parasitized hosts. Subsequent to our prediction, Cronin & Strong (1993b) demonstrated that experienced A.delicatus do not avoid ovipositing in previously self‐parasitized hosts.
Optimal patch leaving rules can be highly sensitive to even very low host discrimination error rates, which may be widespread among parasitoids.
Intraspecific variation in sperm precedence in the bruchid beetle Callosobruchus maculatus
Authors: EADY PAUL 
Published: March 2008

Abstract.

By examining potential sources of intraspecific variation in sperm precedence, the underlying mechanisms of sperm competition in Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) were investigated.
The extent of sperm precedence was not related to either copulatory behaviour or body size (male and female).
The extent of sperm precedence increased during the egg‐laying period, suggesting that the stratification of sperm within the spermatheca is not the mechanism of sperm precedence.
Direct removal of sperm from the female's reproductive tract was not observed.
Four other mechanisms (not mutually exclusive) are proposed to account for last‐male sperm precedence in this species.
Forager polymorphism, size‐matching, and load delivery in the leaf‐cutting ant, Atta cephalotes
Authors: WETTERER JAMES K. 
Published: March 2008

Abstract.

This study examined the importance of forager polymorphism and division of labour among foragers of different size for the economics of load delivery in a leaf‐cutting ant, Atta cephalotes (L.). I collected A.cephalotes foragers coming down trees carrying leaf fragments to evaluate the degree of match between forager mass and the density (mass per unit area) of leaves being cut, and to quantify how this match affects whether the mass of leaf fragments cut by the ants are within the range which maximizes the rate and efficiency of load delivery.
Foragers ranged 23‐fold in mass (1.4–32.1 mg). On average, larger workers cut at denser leaf sources. Leaf fragment area increased with ant mass, but relative area (fragment area/ant mass) decreased with ant mass. The density of a leaf type had little or no effect on the area cut by ants of a given size. As a result, ants of a given mass cut heavier fragments from the denser leaves. The effect of leaf density, however, was partly counteracted at the colony level by recruitment of larger ants, which cut smaller area fragments relative to their body mass, to cut at denser leaf sources.
Despite a fairly high variance in the relationship between ant mass and fragment mass, overall 87% of the laden ants (74–100% for different trees) carried leaf fragments in the 1.5–6 times body mass range. Earlier studies indicate that loads in this range yield the highest biomass transport rate and transport efficiency. Thus, the variance falls within bounds such that it has little effect on load transport efficiency. Having a broad range in optimal load mass may be considered an adaptation to the expected variability in load masses.
If there were no correlation between ant mass and leaf density, mismatches between ant mass and load mass would be more common than observed. Thus, size‐matching of larger workers to cut denser leaves increases the rate and ergonomic efficiency of load delivery.
Life history traits related to resource partitioning between synhospitalic species of Colocasiomyia (Diptera, Drosophilidae) breeding in inflorescences of Alocasia odora (Araceae)
Authors: YAFUSO MASAKO 
Published: March 2008

Abstract.

Two closely related species of Colocasiomyia alocasiae (Okada) and C.xenalocasiae (Okada) (Diptera, Drosophilidae) breed in inflorescences of Alocasia odora C. Koch (Araceae), a hermaphroditic understorey clonal herb.
The two drosophilid species form a synhospitalic pair in Okinawa with alocasiae breeding in the upper half of the inflorescence and xenalocasiae breeding in the lower half.
C.alocasiae also has the following combination of life history traits: small body size, many eggs, and early reproductive maturity. In contrast, xenalocasiae can be described as having larger body size, fewer eggs, and delayed reproductive maturity.
Resource partitioning between the two species on the same host may be affected by these life history traits which are associated with their larval habitats.
Population structure in the small ermine moth Yponomeuta padelus: an estimate of male dispersal
Authors: BROOKES MARTIN I. , BUTLIN ROGER K. 
Published: March 2008

Abstract.

An extensive investigation was carried out into the structure of a large, effectively continuous population of Yponomeuta padellus Latreille, feeding on hawthorn, Crataegus monogyna, and blackthorn, Prunus spinosa.
Mark—recapture studies were used to obtain direct estimates of the male dispersal rate, σ, in two successive years.
Dispersal was found to be extremely localized with respect to the total area of the study population. Estimates of u ranged from a minimum of 2.47 m to a maximum of 12.5 m.
Limited dispersal could be an important factor governing the genetic differentiation of Y.padellus populations, and its implications for the supposed existence of host races in this species are discussed.
Geographical and developmental components of adult size of neotropicalAnopheles(Nyssorhynchus)
Authors: LOUNIBOS L.P. 
Published: March 2008

Abstract.Wing lengths were used as indicators of size of host‐seeking females of four species of malaria vectors captured at human or animal baits in South America.Geographic variation in size was observed among populations ofAnopheles aquasalisandA.nuneztovari, but notA.albitarsisorA.triannulatus.The frequency distributions of wing lengths in large collections of host‐seekingA.aquasalisandA.albitarsisexhibited significant negative skewness, suggesting that the preponderance of biting females approached maximum size.Relationships between season or physiological state (parity, blood, eggs) and the sizes of host‐seeking females were not generally significant.WhenA.aquasalis, A.albitarsisandA.nuneztovariwere reared separately at two larval densities, initial density, but not species, significantly affected wing lengths. Significant species × density interactions may be attributable to species‐specific responses to density.Compared to other mosquitoes, the sizes of host‐seekingAnopheles(Nyssorhynchus) varied little within natural populations. Laboratory studies on the fitness of unnaturally small malaria vectors may bear little relevance to the fitness of host‐seekingAnophelesin nature.
Predation and avoidance of tough leaves by aquatic larvae of the moth Parapoynx rugosalis (Lepidoptera: Pyralidae)
Authors: MUELLER ULRICH G. , DEARING M. DENISE 
Published: March 2008

Abstract.

Aquatic larvae of the pyralid moth Parapoynx rugosalis Möschler repeatedly construct protective cases by cutting portions (discs) from leaves of the waterlily Nymphaea ampla and sandwich themselves between the disc and the underside of the host leaf. Construction of a new case requires leaving the old case, thus increasing exposure to predators and parasites.
In an experiment, larvae with protective cases experienced no mortality due to predation by fish, whereas larvae without cases experienced substantial predation.
In a series of choice tests, larvae preferentially selected young, tender leaves over old, tough leaves for construction of cases, and larvae spent significantly less time completing their shelters when cutting discs from young, tender leaves.
A partial explanation of why larvae select young, tender leaves for construction of their protective shelters may be that exposure time to predators during construction is minimized.
The same mechanism linking preferences for tender leaves to reduced exposure to predators during construction may also apply to other insect herbivores exhibiting leaf‐rolling or case‐building behaviour.
Seasonal and spatial population loads of a tropical insect: the case of the coffee leaf‐miner in Mexico
Authors: NESTEL DAVID , DICKSCHEN FRANZISCA , ALTIERI MIGUEL A. 
Published: March 2008

Abstract.

The effect of weather fluctuations in a tropical rain forest upon a leaf‐miner (the coffee leaf‐miner Leucoptera coffeella Guerin‐Meneville (Lepidoptera: Lyonetiidae)) was studied in Veracruz, Mexico. The combined effect of temperature and precipitation upon the leaf‐miner populations was investigated in coffee plantations located along an elevation transect and throughout the annual seasons. The effect of plant diversity, displayed by the presence or absence of shade trees in coffee plantations, upon the population loads of the leaf‐miner was also investigated.
The leaf‐miner population increased significantly during the period of intermediate temperature and low precipitation (spring season). Elevation also affected the population load of the insect: leaf‐miner populations were larger at low elevations (where temperatures are high and precipitation low) than at high elevations.
Plant structural diversity did not affect the population loads of the leaf‐miner.
The results indicate that the direct and indirect effects of temperature and precipitation are significant factors in the population dynamics of the coffee leafminer. It is suggested that even moderate fluctuations in climatic conditions in tropical and subtropical regions may also play an important role in the dynamics of tropical insect populations, similar to that found in temperate zones where climatic fluctuations are extreme.
Effect of temperature and leaf age on growth versus moulting time of a generalist caterpillar fed plantain (Plantago lanceolata)
Authors: STAMP N.E. , BOWERS M.D. 
Published: March 2008

Abstract.

The simultaneous effects of daytime temperature (20°C versus 30°C) and leaf age (new versus intermediate‐aged) on a generalist insect herbivore were examined. Fourth‐instar Spilosoma congrua caterpillars were tested on plantain (Plantago lanceolata), one of this lepidopteran species’host plants, for which the major defensive chemicals, iridoid glycosides (aucubin and catalpol), could be quantified.
Cool temperature depressed amount of food eaten, amount of frass, and consumption and growth rates, and increased the proportion of time spent in the non‐feeding period (from head‐capsule slippage to ecdysis).
Average iridoid glycoside concentration was 2.8% dry weight (d.w.) in new leaves and 1.6% d.w. in intermediate‐aged leaves. When fed new leaves, the caterpillars had a higher efficiency of conversion of ingested food to biomass and a higher growth rate than those fed intermediate‐aged leaves. Furthermore, the proportion of time spent in the non‐feeding period was prolonged by a diet of intermediate‐aged leaves.
A second experiment showed that the percentage dry weight of aucubin, catalpol and total iridoid glycosides increased over 24 h in incubated, excised leaves, which meant that the caterpillars in the first experiment experienced somewhat higher iridoid glycoside concentrations than the levels in fresh leaves.
Overall, these results indicate that this generalist should prefer new plantain leaves over older leaves even though new leaves contain higher concentrations of iridoid glycosides.
Time‐lags in insect response to plant productivity: significance for plant‐insect interactions in deserts
Authors: AYAL YORAM 
Published: March 2008

Abstract.

The interactions between the univoltine mirid bug Cupsodes infuscatus and its food plant, the geophyte Asphodelus ramosus, were studied in the Negev desert for a 5 year period. The bug feeds mainly on Asphodelus inflorescence meristems, flowers and fruits, and in some years may destroy more than 95% of the plant population expected fruit production.
Asphodelus expected fruit production fluctuated widely during the study period, but was not related to precipitation. Cupsodes density was related to the plant expected fruit production, but with a 1 year time lag. In years of high inflorescence production, a high per‐capita reproduction of the bug resulted in a dense bug population in the following year. This dense population then decimated the plant fruit production, became food limited and had a low per‐capita reproduction.
This kind of time lag is expected to be common among desert insect herbivores that specialize in using ephemeral resources. The rare years of high plant production are in general preceded and followed by years of low plant production. Hence, in years which contribute most to plant reserves (seed, underground storage organs), insect herbivores are relatively rare as a result of food limitation in preceding low production years. But the insect populations which build up during years of high plant production decimate their food resources and become food limited in subsequent years with low plant production.
Thus, herbivorous insects seem to have a limited ability to affect plant population dynamics in desert ecosystems. In contrast, the potential appears to be much greater for herbivorous insects to be regulated by their food plants.
The role of leaf‐cutting ant workers (Hymenoptera: Formicidae) in fungus garden maintenance
Authors: BASS M. , CHERRETT J. M. 
Published: March 2008

Abstract.We studied the role of leaf‐cutting ant workers (Atta sexdens(L.) in fungus garden maintenance, by temporarily excluding workers from the garden. This increased its subsequent attractiveness, as expressed by an increase in the numbers of workers licking it.The length of free mycelia on areas of the garden from which workers were excluded increased but was reduced again when workers were returned. Workers therefore removed hyphae from the garden surface.The maximum‘isolation effect’was obtained by preventing ant access for 2–3 days, after which the effect declined. Removing staphylae from portions of garden kept ant‐free for 4 and 6 days restored the effect, as the ants were not distracted by harvesting staphylae. Portions of garden kept ant‐free for longer than this were no more attractive than non‐isolated control garden.Workers were highly efficient in detecting and removing contaminants from their fungus garden. Samples of garden could be isolated from workers for up to 12 days before major growth of contaminants occurred, and this contrasted with the maximum of 6 days for the isolation effect on licking. The isolation effect was therefore not a response to contaminant growths on the garden.Workers on the garden surface may remove hyphae for nutritional reasons, or to‘prune’their fungus and stimulate its growth. In either case, the result is a regulation of fungal growth.