摘要:

AbstractNorberg, R. Å. (Department of Zoology, University of Gothenburg, Göteborg, Sweden.)Flight characteristics of two plume moths, Alucita pentadactylaL. andOrneodes hexadactylaL. (Microlepidoptera).Zool. Scripta 1 (6): 241–246,1972.–Multiple exposure photographs of up to 100 exposures/sec were taken on two plume moth species in free, unrestrained flight, in order to determine approximate lift/drag ratios and other functional characteristics of their wings, which are of a remarkable structure for insects of this size. InAlucitathe forewing is cleft in two fringed lobes, the hind‐wing in three, while inOrneodesboth forewing and hindwing are deeply cleft in six very narrow, fringed lobes. Wing stroke frequencies are ca. 33 Hz inA. pentadactylaand ca. 40 Hz inO. hexadactyla.During both the downstroke and the upstroke the fringed wing lobes lie edge against edge, thus forming a continuous wing surface. The upstroke seems to contribute no useful forces inA. pentadactyla, possibly some propulsive force inO. hexadactyla.The wings are strongly supinated in the upstroke to minimize drag. From relative wind diagrams, lift/drag ratios of 1.1 and 1.4 (minimum values) can be read forA. pentadactylaandO. hexadactyla, respectively. It is thus clear that these species do not make more use of drag forces than of lift forces. However, inA. pentadactylathe drag force in the downstroke may be almost as large as the lift force. Since drag certainly is small in the upstroke, the drag force probably contributes significantly to useful forces for flight inA. pentadactyla.These plume moths operate at Reynolds numbers of ca. 700. Reynolds numbers are calculated for very small insects. It is obvious that the wings of the smallest insects must be operating at Reynolds numbers of about 1. The fringed wings of small insects are briefly di

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1972.tb00573.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractNorberg, R. Å. (Department of Zoology, University of Gothenburg, Göteborg, Sweden.)Evolution of flight in insects.Zool. Scripta 1 (6): 247–250, 1972.–Two hypotheses on the origin of flight in insects are discussed. 1. Gliding hypothesis. If wings and flight originated in ca. 1 cm large, or larger, insects, a leaping type seems to be a more probable candidate than a non‐leaping one, since the former type has, with certainty, a high frequency of voluntary air excursions, during which any extensions come into play. Furthermore, it may attain the equilibrium gliding speed by jumping, and need not, if arboreal, lose any height on a steep initial fall to gain speed. 2. Floating hypothesis. The hypothesis presented here is a modified version of that put forward by Wigglesworth in 1963. It is suggested that wings may have originated in very small insects as thin dorsolateral, fringed extensions (like the wings of the smallest flying insects) acting as viscous drag producers, enabling the insects to float in the air with a very slow sinking speed and to be dispersed passively over long distances by thermal convection currents. Mov‐ability of the wings would have increased practicability on the ground, and selection pressure for this could have brought about preadaptation for active flapping flight. Monophyly versus convergence of insect wings of conventional type (aerofoil function) is discusse

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1972.tb00574.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractKarling, T. G. (Section of Invertebrate Zoology, Swedish Museum of Natural History, Stockholm, Sweden), Valeria Mack‐Fira, and Jürgen Dörjes.First report on marine microturbellarians from Hawaii.Zool. Scripta 1 (6): 251–270, 1972.–The material presented here consists of:Cilionema hawaiiensisgen. et sp. n.,Microvahine corallicolagen. et sp. n.,Archiloa subtilissp. n.,Minona bistyliferasp. n.,Duplominona kaneoheisp. n.,Archimonocelis heljrichisp. n.,Ulelga variodentatasp. n.,Notocelis gullmarensis maculatassp. n.,Cylindrcstoma monotrochum(Graff),Plagiostomum acoluthumMarcus,Gyratrix hermaphroditusEhrenberg andAustrorhynchus pectatusKarling. The anatomy of the species is described and their taxonomy discussed. Views are given on the comparative anatomy of the bursal organs. The ecology and the biogeography of the species are briefly di

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1972.tb00575.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractLansbury, I. (University Museum, Oxford, U.K.)A revision of the genusTelmatotrephesStdl (Hemiptera‐Heteroptera, Nepidae).Zool. Scripta 1 (6): 271–286.–Telmatotrephesis redefined and compared with related Oriental genera. A key to species is given and two new species (T. ecuadorensissp.n. andT. chinensissp.n.) are described and one species is placed in synonymy. Some observations are made on the systematic position and distribution ofTelmatotrephesin relation to other nepid g

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1972.tb00576.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY