摘要:

Within the Astigmata, setal homologies with the general chaetotaxic systems developed for acariform mites by F. Grandjean have never been convincingly established. This study deals with all body regions, exclusive of legs and gnathosoma, mostly utilizing as models astigmatid species from three different families. Six hypotheses which attempt to explain the ontogeny of segments, setae and cupules in the caudal bend region are compared using three‐dimensional views obtained by scanning electron microscopy. The hypotheses are evaluated by in‐group comparisons testing their consistency with presumed segmental boundaries, and by out‐group comparisons with oribatid mites. The strongest, most parsimonious hypothesis suggests that larval astigmatid mites possess segment F, but not its setae, and the two pairs posterior to segment F arehlandh2, whilst the five setae added in the protonymph areh3,f2andps1–3. Six pairs of structures on the deutonymphal anal plate are identified as modified setae, and evidence supporting their homologies with setae of other instars is discussed for the first time. A comparison of the principal chaetotaxic systems used for the dorsal and anal regions of the Astigmata is presented. Application of Grandjean's setal signatures to these regions, as well as to the coxisternal and genital regions, is discussed and illustrated by e

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04291.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

This study investigates differences in mating success in male crested newts, Triturus cristatus. In experiments, mating success varies considerably between individual males. Male size affects mating success, but the maximal height of the male's crest is more important. Male size and crest height are correlated, but in partial correlation analysis only crest height is significantly correlated with mating success. Motivation is also an important factor in determining male mating success as males that had been isolated for a week were more successful than freshly caught males. Newts might be limited in their ability to produce spermatophores, and isolation gives the male time to produce more spermatophores. It is likely that motivational state is less important in a natural population than size and crest height, because wild males are often interrupted during courtship before spermatophore deposition and hence are highly motivated to mate.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04292.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The energy requirements of reproducing and non‐reproducing females of three species ofCrocidura(C. russula, C. viaria, C. olivieri), and two species ofSorex(S. coronatus, S. minutus) were measured. Members of these two genera show different rates of metabolism and reproductive strategies (extreme altriciality and larger litter size inSorex). During pregnancy, the daily energy intake (on either an absolute or a mass‐specific basis) remained close to the non‐reproductive value in all species. The absolute energy intake increased strongly after parturition and was influenced by the litter size. Peak energy intake of lactating females was extremely high, typically between 100% and 200% above the non‐reproductive requirements in theCrociduraand about 300% above the non‐reproductive intake in theSorex. The mass‐specific daily energy intake was reduced during lactation in the three smaller species but not in C. viaria and C. olivieri. This decrease probably involves the different thermoregulatory abilities and/or basal rate of metabolism of the pups. Average reproductive effort was about 50%, in theCrociduraspecies and above 150% in theSorexspecies. The higher effort in the latter is partly due to a larger litter size. But in addition, extreme altriciality in theSorexleads to an earlier increase in the energy requirements and thus is an energetically more expensive reproductive mode. The present results support the hypothesis that a higher basal rate of metabolism is associated with a higher reproductive effor

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04293.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

We investigated the foraging behaviour of little penguins using a new archival electronic activity recorder which simultaneously measures speed and depth against time. We present the first integrated data of foraging behaviour of two little penguins, from which we were able to distinguish between several types of travelling and foraging behaviours. The little penguins foraged mainly within 15 m of the surface and travelled at speeds between 8 and 9 km h‐1. Using attachments ranging between 1.4 and 11.8% penguin cross‐sectional area (0.1 and 6% penguin mass), and isotopic water, we also assessed the effects of carrying devices while foraging. Both water influx and metabolic rates were significantly lower in penguins carrying devices, compared to penguins foraging without devices attached. Even the relatively small attachments resulted in a decreased foraging efficiency and we suggest that there is no simple or fixed relationship between size of device and the effect on the bea

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04294.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The scent‐marking behaviour of a group of six saddle‐back tamarins,Saguinus fuscicollis nigrifrons, was studied in the Amazon rain forest of north‐eastern Peru. Three types of scent marking were recognized: anogenital marking, suprapubic marking and sternal marking. Anogenital marking was the most frequent type. Two or more scent‐marking acts of the same or different type were generally combined into sequences. Most scent‐marking was performed on branches and lianas; trunks were infrequently used. The tamarins mainly marked on horizontal or inclined substrata with diameters between 3 and 10 cm and a height between I and 10 m. The temporal distribution of scent‐marking exhibited a maximum in the early morning between 06:00 and 07:00h and a minimum between 16:00 and 17:00h. The majority of scent‐marking occurred in the peripheral areas of the home‐range. The spatial distribution of scent‐marking was correlated with the intensity of home‐range use. No elevated frequencies of scent‐marking were observed during intergroup encounters. The results of this field study are compared with findings from laboratory studies, and hypotheses concerning the function of scent

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04295.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A national survey of the incidence of daylight flying of bats in mainland Britain was organized from September 1985 until March 1988. A total of 420 records of daylight flying were received by 1 May 1988. One hundred and forty‐four reports were from winter (October to March), 271 from summer (April to September) and five were undated. Peak activity occurred during April and in August/September.Activity in both winter and summer was greatest between 12:00 and 16:00h. The numbers of bats involved in each sighting varied between 1 and 200. In summer 87% and in winter 91% of observations were of single individuals. Numbers of daylight‐flying bats, relative to roost visitor reports sent to the Nature Conservancy Council, increased with increasing latitude during both summer and winter. This means that an individual is more likely to fly in daylight the further north in Britain it lives. The effect of day‐to‐day variation in climatic variables on emergence was investigated for records from 1987. In April 1987 emergence occurred on days which followed significantly cooler nights than nights preceding days without emergence. During the remainder of the summer of 1987, however, no climatic effects were significant. During winter 1987 emergence occurred on days which were significantly warmer and sunnier.These data suggest that during summer the primary function of emergence during daylight is to feed to make good energy deficits that have accrued because of inadequate intake during nocturnal foraging. During winter, bats time their daylight emergences to coincide with good feeding conditions, as has been shown previously for winter nocturnal emergence. It is possible daylight emergence occurs during winter primarily because the endogenous cycle during hibernal torpor cannot accurately synchronize arousal with periods of d

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04296.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Within five species of parasitoid wasps of the families Pteromalidae (Morodora armataGahan,Muscidifurax zaraptorK.&L.,Nasonia vitripennis(Walker)), Bethylidae (Goniozus legneriGordh), and Tiphiidae (Myzinum quinquecinctum(Fabricius)), we found significant positive correlations between female body size and both the number and the size of the mature oocytes present in the ovaries. These data are discussed with reference to current clutch size and egg size models and biological information available on these species.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04297.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

This paper offers an analysis of the recruitment and normalized power output of the slow oxidative (red) axial muscles of the carp, during swimming in two different modes. Recruitment patterns of the muscle fibres and swimming movements were measured by synchronized electromyography and cinematography. The ultrastructure of the muscle fibres along the trunk was measured by electron microscopy. Strain fluctuations and normalized power along the trunk were estimated using a model, as direct measurement was impossible. The model takes into account structural parameters of the sarcomeres, modulation of sarcomere force as a result of changing sarcomere length, modulation of cross‐bridge force owing to the force‐velocity relationship, and rate of tension rise and of tension decline as a result of fibre properties and stimulation. In continuous swimming, the amplitude of the fluctuations in the strain was constant along the trunk, owing to a remarkable coherence between the amplitude of body curvature and the position along the body of the red muscle fibres with respect to the vertebral column. However, the strain range and speed of contraction at which the fibres were active changed along the trunk in continuous swimming as well as in ‘kick and glide swimming’. During continuous swimming, the fibres along the trunk had a period of negative active power production followed by a period of positive power production. Anteriorly, the positive phase was most important, with a close to optimal power production in a plateau phase, so that net positive work was produced in a swimming cycle. Posteriorly, net negative work was done. In the anal region, the amounts of positive and negative work almost balanced each other. During the first tail strike in intermittent swimming, peak positive normalized work for an activated fibre was produced in the anal region. For this initial tail strike, fast muscle fibres were calculated to work more effectively than slow fibres. Fast fibres were needed to generate kick and glide s

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04298.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Prey selection bySomaniathelphusa sinensis(Parathelphusidae) among five gastropod species (two prosobranchs, three pulmonates) was associated with two snail attributes. First, the degree of defence of the tissues by the shell, approximated by shell weight (SW)/tissue dry weight (M). Snails with the heaviest shells (Sinotaia quadrata: Viviparidae) could not be attacked successfully by any crabs, and those with somewhat lighter shells (Melanoides tuberculata: Thiaridae) were protected from small crabs. Secondly, among those light‐shelled snails which could be attacked successfully, prey value (M/handling time,Ht) determined rank order of preference.Biomphalaria straminea(Planorbidae), with the highestM/Ht, was the species most readily eaten. When presented with a single snail species, crabs selected among different‐sizedB. stramineain a way which maximizedM/Ht. This preference was most strongly exhibited by small crabs. A lack of size selection forRadix plicatulus(Lymnaeidae) prey was in agreement with an absence of a clear influence of size onHtfor this species. Manipulation ofM/Htby attaching plastic discs toB. stramineashells (thereby increasingHt) resulted in patterns of prey selection in accordance with the hypothesis that foragingS. sinensismaximizedM/H1.Partial consumption ofR. plicatulus, and to a lesser degreePhysella acuta(Physidae), was common when groups of snails were presented to individual crabs, and occurred more frequently when large snails were offered. Partial consumption and subsequent rejection of large snails may have masked selection for small prey which were rarely abandoned before being completely eaten.The implications of patterns of prey selection were discussed with reference to the influence of crab predation on snail distribution and abundance in Hong Kong fresh wat

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04299.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Mean body weights of baboons differ considerably between populations for both males and females. This paper examines possible environmental causes of these differences. Mean annual rainfall and mean annual temperature are shown to be the two main factors responsible. Mean body weights for both sexes are a quadratic function of rainfall. Possible reasons why this might be so are examined.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1990.tb04300.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY