摘要:

Abstract.1. The incidence of diapause in twenty‐three populations ofPlodia interpunctellafrom fifteen countries representing all continents of the world was examined. The origins of populations varied from 52°N to 35°S and included two from equatorial regions.2. Diapause occurred in all population samples at 20°C in short photoperiods (LD 11:13) and in continuous light, although the proportion of larvae doing so was less than 25% in samples from the equatorial belt.3. The critical photoperiod was less than 13 h in five samples, all from the tropics, or southern hemisphere. The remaining samples, including three from the southern hemisphere, had critical photoperiods of 13 h or more.4. Diapause was completely avoided by a 15 h photoperiod at 20°C in thirteen of the twenty‐three samples, including all but one of those from the southern hemisphere.5. At 25°C larvae entered diapause in short photoperiods (LD 9:15) in about half of the samples tested in both hemispheres, but the proportion per sample was always less than

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00575.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Wavelength dispersive X‐ray fluorescence spectrometry was used to make quantitative determinations of the elemental composition (chemoprints) of individuals and of bulked males and females ofNoctua pronuba.2. Females caught in light traps at Rothamsted on two successive nights in August 1978 could be separated by significant differences in content of five elements, S, K, Ca, Cu and Zn. Two females, thought on biological grounds to be immigrants, could be distinguished from other, probably resident, females trapped at the same time.3. Males and females were different in respect of four elements, S, Cl, K and Ca, three of which, S, K, and Ca, were also discriminants between nightly populations of female

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00576.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Samples from two populations of the satyrid butterfly,Cercyonis pegalawere collected and analysed for palatability and incidence of avian predation.2. A series of feeding experiments indicated thatC. pegalais indeed palatable.3. A high proportion of individuals in both samples showed evidence of avian attack: 10.2% in Amherst and 7.1% in Easthampton; this frequency is much higher than usually described for studies of this sort.4. The two samples showed no significant differences with respect to frequency of damaged specimens.5. There was no consistent location of damage on individuals or significant differences between the two samples.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00577.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1.Sphex ichneumoneusare solitary, ground‐nesting wasps with apparently broad nesting requirements.2. Nest‐site selecting behaviour involves four levels of decisions. First, the wasps are not active unless temperatures are high and they are less active during cloudy weather. Second, at the beginning of a nesting sequence they generally fly to the site from which they emerged, but occasionally they fly to other flat, vegetation‐free areas. Third, after landing, they engage in a predigging search of the area, walking around, looking into and briefly digging in the nests of other wasps. In this way they apparently compare and choose to begin digging in the warmest areas available which are not too close to other nests. Fourth, if the soil is too soft and collapses or if it is too hard‐packed, the wasp resumes the predigging search. The preference for digging within a range of compactness means that they generally choose sandy loam.3. Theory would suggest that the wasps may spend an optimal amount of time in the predigging search behaviour and that frequency‐dependent selection may be an important factor in the choice of nesting sites.4. By choosing nesting sites according to these rules, the wasps are ensuring that their offspring develop in the warmest and best‐drained soil

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00578.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. The male songs of two of the commonest cicadas in southern France are described with oscillograms.2. Males ofCicada orniL. aggregate during calling whilst those ofLyristes plebeius(Scop.) space themselves out.3. Both species are widely polyphagous on trees and shrubs, butL. plebeiussings from thinner stems than doesC. orni4. Such behaviour may result in the spatial separation of different species in the same habitat.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00579.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. A single nest of the black surface‐foraging nasute termiteHospitalitermes umbrinuswas studied for 5 days in July 1978. Foraging parties of workers and soldiers tend to leave the nest in a continuous stream in the evening and return carrying food balls during the following morning.2. An estimated maximum of 500000 individuals were involved in the foraging excursions. At a density of 3 nests ha‐1, the total foraging population is estimated as being at least 180 m‐2.3. The colony brought back an estimated 46.4 g (d.w.) of food in 4 days. The biomass of the colony was estimated at 349 g (d.w.) (c.1396 g w.w.) excluding alates and the consumption at 8.3 mg (d.w.) g‐1(w.w.) d‐1.4. The food balls were found to be of two types, light and dark coloured. The light balls contained wood constituents, bryophytes, blue‐green algae and fungal hyphae while the dark balls consisted mainly of lichens and their spores.5. Swarming began at 14.30 hours on 9 July and ended with the nuptial flight at 17.32 hours. About 3000 alates were released. They climbed to 9 m on a tree before

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00580.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1.Atta sexdenschanges diel periods of foraging, the size of its foraging territory, the numbers and lengths of foraging trails, and its rate of foraging with respect to seasonality in subtropical Paraguay. Leaf loads are significantly larger in warmer months than loads carried in cooler months.2. Foragers segregate into three labour groups in the field: a small subset climb trees, cut large quantities of vegetation, and drop them to the ground; the second subset of foragers searches out these leaf caches, cut diem into smaller pieces, and carry and deposit the leaf fragments on the foraging trail; the third subset of workers retrieves leaf fragments on the trail and carry them to the nest.3. Pitfall trapping shows a large degree of patchiness in activity, with media workers dominating the foraging population, more so closer to vegetation which is being harvested.4. The recovery efficiency of the multi‐staged foraging behaviour is estimated to be only 49%, with the recovery of leaf caches near 50%. The impact ofA. sexdensmay, thus, be twice as great as previous estimates on their herbivor

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00581.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1.Chorthippus brunneuswere collected from twenty‐two different sites in Nottinghamshire, Derbyshire and Essex.2. Discrete characters of the head, pronotum and forewings and hind femora were scored. The results were compared with the types of habitat from which the grasshoppers were collected.3. Associations between striped and mottle‐winged varieties were found.4. The relationships between colour and habitat were exami

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00582.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Two populations of bagworms were censused in Ohio for 6 and 5 years respectively, to determine the influence of major pupal mortality factors. Bagworm densities declined from 2.3 bags per 30 cm of terminal branch to zero.2. No single key mortality factor was identified in population trends. Parasitic Hymenoptera were common but variable in effect. Avian predation may have been important in reducing one population, while the other was exterminated after a drastic change in sex ratio to favour males.

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00583.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Abstract.1. Attack rates and handling times are measured by a series of separate functional response experiments for each instar ofNotonecta glaucaattacking four size classesof Daphnia magnaas prey. The resulting attack rate and handling time surfaces are complex, with maximum attack rates for small predators attacking small prey, and large predators attacking large prey. AdultNotonectahave lower attack rates than the two previous juvenile instars (4 and 5).2. The literature on attack rates and handling times in other predator—prey interactions that involve a series of different predator and prey size or age classes is reviewed in the context of theNotonecta‐Daphniaresults. The data suggest that small predator instars will usually compete with large instars for food, unless there is spatial or temporal separation between them.3. Complex attack rate and handling time surfaces are to be expected wherever a wide range of prey and predator sizes is involved.4. Size related changes in attack rates and handling times can introduce very complex dynamics into predator‐prey interac

ISSN:0307-6946    

DOI:10.1111/j.1365-2311.1979.tb00584.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY