摘要:

ABSTRACT.1. Egg sizes and clutch sizes of the grasshoppersChorthippus brunneus(Thunb.) andMyrmeleotettix 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 forM.maculatus, but not forC.brunneus, females with long hind femurs laid large eggs.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00991.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Relationships are examined between mean egg size and possible selection pressures acting on two grasshopper species,Chorthippus brunneus(Thunb.) andMyrmeleotettix maculatus(Thunb.), co‐occurring at three sites in a sand dunes area.2. Heavy eggs were laid where the mean crowding of hatchlings was high in relation to the amount of grasses with thin‐edged leaves. To a lesser extent, large eggs were also found in more desiccating conditions. Mean egg dry weights did not correlate with measures of crowding or measures of crowding in relation to total grass abundance.3. Significant differences in egg size and clutch sizes were observed between the stocks of second generation, laboratory‐rearedM.maculatusfrom three study sites. The significant difference in egg size (site 2 stock>site 1 stock) ran counter to the difference observed in the field but the difference in clutch size (site 3

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00992.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Geographical variability in, and temperature effects on, the mean date of adult flight period and the SD about this date are analysed for two univoltine, grassland butterflies in England and Wales from 1976 to 1985. Data were collected on the Butterfly Monitoring Scheme forManiola jurtina(L.) at twenty‐nine sites andPyronia tithonus(L.) at twenty sites.2. Substantial variability for mean date and SD occurs between years and between sites. Changes in mean date between years tend to occur consistently at different sites. The species show some parallel in variation between sites, especially for mean date.3. June maximum temperature accounts for 95% and 75% of the variation in mean date between years inM. jurtinaandP. tithonus, respectively (r=‐0.97 and ‐0.87). Similar relationships occur for temperatures cumulated over the period of post‐winter development from March to July or August.4. Greater geographical variability in phenology, and a generally less synchronized flight period inM.jurtinamay be associated with broader habitat preferences than inP. tithonus.5. The mean date of adult flight period remains at roughly the same date at more northerly latitudes. InM.jurtinathe flight period becomes more synchronized, begins later and ends earlier in the north.P. tithonusshows little or no indication of such a response to latitude. This is discussed with regard to changes in season length and factors limiting the specie

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00993.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. On the biologically impoverished sub‐Antarctic Ile de la Possession, Iles Crozet,Amblystogenium pacificumPutzeys andA.minimumLuff (Carabidae), both opportunistic carnivores, coexist in fellfield habitat above 120 m altitude, where they hunt prey in inter‐stone spaces.2. Beetles show marked claw wear showing that many individuals survive to breed in their third or later year of adult life, and in some years, particularly inA.minimum, populations consisted largely of very old beetles. This coupled with evidence from ripe egg numbers, of rarity of tenerals and of larvae, shows that adult recruitment rates were usually very low.3. In fellfield the coexisting species pair have non‐overlapping size distributions withA.pacificumthe larger. In moorlandA.pacificumadults occur in isolation and are smaller and overlap the size ranges of both species in fellfield. These facts are interpreted as character displacement or release, reflecting present‐day interspecific competition, probably for food. Supporting evidence was obtained in terms of apparent size‐differential survival of beetles of diffe

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00994.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Host plant relations of closely related species and pseudogamous triploid forms of the planthopper genusRibautodelphaxwere studied.2. From field data and experimental results it is concluded that eleven EuropeanRibautodelphaxspecies and undescribed taxa are monophagous or oligophagous on different grass species. Only twoRibautodelphaxspecies are found on the same grass species in the field.3. Differential host plant relations indicate that four recently discovered taxa are probably true species.4.Ribautodelphaxspecies show a more restricted host plant range in choice experiments compared with breeding tests.5. Choice experiments indicate no differences in host plant preference between males and females of twoRibautodelphaxspecies.6. No differences are found in host plant relations between bisexual species and associated pseudogamous triploid forms.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00995.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Counts of adultScathophaga stercoraria(L.) on cow pats were made in Houghall, County Durham, in 1964 and 1965.2. A spring peak of numbers was due to adults (overwintered mainly as pupae or larvae) maturing and going to dung to breed. Numbers then dropped, rising to one or more peaks in late June—early July. In 1964 there was then a summer drop in numbers until late September. In 1965 high numbers persisted in summer associated with cooler, wetter weather. Autumn peaks in both years persisted until severe frosts or snow.3. Mature adults, developed from eggs laid during the spring peak, form the first generation when breeding in mid‐late June. No clear generations can be identified after this, due to eggs being laid daily (females have successive gonotrophic cycles). Changes in adult numbers breeding reflects survival of eggs and newly‐hatched larvae 5–6 weeks earlier, and lower survival rates of adults in mid‐summer compared with spring and autumn.4. AdultScathophaganumbers in vegetation rose as numbers on dung dropped. Females dissected to count ovariole tunica dilatations showed that most flies in vegetation were immature, with some parous flies hunting insects to develop the next batch of eggs.5. Females on dung were dissected and found to range from immature to seven‐parous. Those gravid for the first time were grossly under‐represented, possibly due to wider dispersal.6. It is suggested that seasonal changes in this r‐strategist cannot be explained simply in terms of generations nor by the occurrence of

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. The effects of colony size and time of reproduction on the survival and size of offspring colonies and on drone production were examined for honey bees,Apis melliferaL. Drone and worker production and survival of parental and offspring colonies were monitored following swarming. Also, the temporal patterns of drone emergence and availability of unmated queens were examined.2. Colony size at swarming was positively correlated with the number of workers invested in offspring colonies and the number of queens produced. However, colony size at swarming was not correlated with the number of offspring colonies produced.3. Swarm size was positively correlated with drone and worker production after swarms were hived. Worker production of hived swarms was positively correlated with colony survival. Offspring queens which inherited a parental nest survived longer than queens in either primary swarms or afterswarms, presumably due to the advantage of inheriting a nest.4. Drone emergence peaked just prior to swarming, the time when unmated queens were available. High drone production by colonies initiated by swarms probably reflected an attempt to reproduce prior to winter. The probabilities of a second swarming cycle within the same year and of surviving the winter were low for colonies initiated from swarms.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00997.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Daily patterns of activity, thoracic temperature (Tth) and thermoregulatory behaviour in relation to environmental conditions were studied in the European skipperThymelicus lineola(Ochsenheimer) adults.2. Daily activity was limited mainly byTth, which in turn was dependent on air temperature (Ta) and sunlight. However, when light intensity fell to22°C. The percentage of both sexes feeding and flying, and courting in the case of males, were positively correlated withTbg.7. In warm weather, males divided their time equally between flying and feeding, while females spent the majority of their time feeding. Feeding bouts were shorter and flying bouts were longer in males than in females. Flight duration in males was positively correlated withTbg.8. Skippers avoided, and, consequently laid fewer eggs in, shady areas.9. Sexual differences in activity patterns in relation to weather reflect differences in the reproductive requirements of the two

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00998.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

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 Gomphoceri

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb00999.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

ABSTRACT.1. Arthropod samples, collected by insecticide fogging ten Bornean lowland rain forest trees, were sorted to species and used to study some of the determinants of faunal similarity of these trees.2. Similarity indices were calculated between pairs of trees for guilds of beetles, beetle families and for different orders and other families of insects.3. Multiple regression analyses of five independent variables of the trees (taxonomic similarity, distance apart, vertical canopy overlap, similarity in tree height, epiphytic load) were carried out against these similarity indices.4. In eight of the eighteen insect groups analysed, taxonomic similarity of the trees is the most important variable affecting their species composition, accounting for a maximum of 29.4% of the variation.5. For the Homoptera, Gryllidae, Anthicidae, Chrysomeloidea and scavengers, distance between the trees and the similarity of the trees’epiphyte load have a greater effect on their faunal similarities than taxonomic similarity of the trees.6. The maximum variation accounted for by variables with significantTratios was 38.6% in the Anthicidae. In four groups, the Formicidae, Heteroptera, Galerucinae and Corylophidae, none of the variables was significant.7. These data may support the view that for many insect groups there is less host‐specificity in the tropics than in temperate regi

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1987.tb01000.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY