摘要:

The systematic relationships between phlaeothripine Thysanoptera species suggest that moss‐feeding is an uncommon and highly derived habit. It is restricted to a single sub‐tribe, the Williamsiellina, which includes two genera,Lissothripswith 17 species andWilliamsiellawith 25 species. Although widely distributed, these genera are particularly common in the New World. Structural variation within and between populations of these small wingless insects is discussed and the conclusion reached that species cannot be defined satisfactorily in the common North AmericanL. muscorum‐group without experimental rearing.Trisclerothripsis synonymized withLissothrips, andProlissothrips, MicrolissothripsandPhthirothripsare synonymized withWilliamsiella. One specific synonym is established, and four new species are described:L. clayaefrom Trinidad,L. okajimaifrom Japan,W. tambopatafrom Peru andW. zapsfrom

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01818.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A large sample ofadult maleCarcinus maenaswas 79% right‐handed and 21% left‐handed. A separate sample of 207 intact adult males was divided into left‐handed and right‐handed crabs and four measurements were taken from all major and minor chelae. Correlation and regression analyses against carapace width on log‐transformed data showed that major chelae of right‐handed crabs grow proportionately higher with increasing size and the ideal mechanical advantage increases; concurrently, the fingers of the minor chelae grow proportionately longer. The data for left‐handed crabs showed greater variability, especially for minor chelae, providing evidence for the concept that left‐handedness arises by reversal of handedness following loss of the major chela from the right‐hand side. Records of handedness in large samples of non‐ocypodid heterochelous brachyuran crabs show a preponderance

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01819.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Wings of representative species of the order Diptera were compared with a simple model structure in which corrugated spars diverge from a V‐shaped leading edge spar. Both develop torsion and camber when subjected to aerodynamic loads, forming a propeller shape. Both the leading edge and the cubitus of flies' wings twist basally, allowing camber to be set up as the media hinges up or down at the arculus. Three different wing types were identified: stiff wings possessing two or three main spars; and wings capable of ventral flexion. In wings possessing only two spars, found mainly in the Nematocera, control of camber is achieved largely by the use of cross veins. Wing control and flight are generally imprecise. The third spar, found in most Brachycera, in the Syrphidae and in the Conopidae controls camber and helps support a broader wing. Finer control of camber is exerted by marginal cross veins, and these insects generally have precise, darting flight. Ventral flexion mechanisms are found in the Simuliidae, the Stratiomyiidae, and widely in the Schizophora. Control of ventral flexion, which occurs at the end of the downstroke, allows fast, unpredictable manoeuvres. Functional similarities indicate either phylogenetic relationship or convergenc

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01820.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A new stem chordate,Prokopiytis mergli, from the Middle Ordovician (Llandeilo) of Bohemia, Czechoslovakia is reconstructed and described. It proves to be the most crownward cornute yet known, sharing with the mitrates (primitive crown chordates) a number of derived features unknown in other cornutes. Such features include: the position of the gonopore‐anus, the absence of major dorsal plates from the fore tail and the expansion of the marginal plates of the head onto the dorsal surface. Some other characteristics ofP. mergliare a fore tail composed of only three segments and an elongate head. Only three hind‐tail ossicles are known. The elongate head and small number of fore‐tail segments are autapomorphies ofP. mergli. The locomotory cycle is reconstructed and it is concluded thatP. merglimoved rearwards, pulled largely by its mid and hind tail. The calcichordate theory is defended and the orientation of the mitrates considered.P. merglireinforces the view that the convex surface of the mitrates was ventral in life. The origin of the atrial chambers of mitrates is discussed and a new homology proposed between the anterior ventral fore‐tail plates of cornutes and what were formerly called plates g and j of mitrates.Nový chordát z kmenové skupiny/stem‐group/Cornuta zeského Ilandeila, pechod mezi skupinami Cornuta a Mitrata. V práci je popsán a rekonstruován nový zástupce kmene chordátuProkopicystis mergligen. et sp. n., z eského llandeila/eskoslovensko/. Jde o dosud známého nejvýe organizovaného kornuta, vykazukícíhoadu znaku shodných s chordáty mitrátníimi a zcela neznámýc u ostatních pedstavitelå skupiny Cornuta. Tyto znaky zahrnují: pozici gonopor‐análníiho otvoru, nepítomnost hlavních dorzálních desek v proximálníásti ocasu a expanzi marginálníc desek hlav na dorzální stranu. K dalím charakteristickým znakåum druhuP. merglipatí protáhlá hlava a proximálníást ocasu tvoená jen temi segmenty. V distálníásti ocasu jsou rovn známy jen 3 destiky. Protáhá halva a maly pocet segmentåu proximálníásti ocasu jsou u.P. mergliautapomorfiemi. V práci je také rekonstruován pohybový cyklus ivoicha se závrem, eP. merglise pohyboval dozadu, pozvolným tahem stední a zadníáSTI OCASU>Je zde hájena tzv. kalcichordátová teorie a diskutována orientace mitrátåu. VyAsledky studia podporují domnnku, e skupiny Mitrata byla za ivota konvexní strana jejich theky stranou ventrální. Je diskutován påuvod atriálnich komaůrek skupiny Mitrata. Souasn jsou pova o

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01821.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The coral‐treaders (Hermatobatidae) are the only exclusively marine family of insects. Observations in the Cook Islands, Samoa, Tonga and Fiji show that the insects can be abundant on shores that provide rocks with cavities that remain air‐filled during high tide. The zone of suitable habitats for the insects is restricted to a narrow (c.20 cm) vertical band roughly centred around Mean Low Water Neaps. Transplant experiments show that the insects are unable to survive above or below this zone. The insects emerge from their rocky crevices about an hour before low tide, swim on the water surface during low tide, and return to their crevices about an hour after the tide has turned. There are only four larval instars, which can be readily separated by their morphology. Electron microscope studies show that the insects are clothed in a layer of micro‐hairs of unique design: a short tapering shaft tipped with a sphere. These micro‐hairs may act as a plastron: their distribution corresponds precisely to the pattern of the silvery ‘air‐layer’ seen when the insects are submerged, their spherical tips provide a regular array that could support an air‐water interface, they occur at high densities (up to 3.5 times 106mm‐2), and the layer makes connection with the thoracic spiracles. Half the insects were able to survive submergence in recirculated seawater for 12 hours. The adults appear to swim further from shore than the larvae, and they were observed copulati

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01822.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1989.tb01818a.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY