3. ParasitesJournal of Animal Ecology, Vol. 28, No. 2 (Nov., 1959), pp. 405-406Published by: British Ecological SocietyStable URL: http://www.jstor.org/stable/2102 .

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Parasites 405

Surtees, G. (1959). Influence of larval population density on fluctuation in mosquito numbers. Nature, Lond. 183, 269-270.

Concludes that fluctuations of Aedes aegyptii depend upon larval density, not on climatic conditions.

Swennen, C. & Baan, G. van der (1959). Tracking birds on tidal flats and beaches. Brit. Birds, 52, 15-18.

Descriptive notes on photographs of marks left by birds and the holes of some prey species of marine worms.

Tarshis, I. B. (1958). Feeding techniques for bloodsucking arthropods. Proc. 10th Int. Congr. Ent., Montreal, 1956, 3, 767-784.

An apparatus and technique are described for the in vitro feeding of fleas, mosquitoes and ticks.

Utida, S. (1957). Population fluctuation, an experimental and theoretical approach. Cold Spr. Harb. Symp. Quant. Biol. 22, 139-151.

Discusses fluctuation of population under constant environmental conditions relative to (1) a single species population, (2) a host parasite system, (3) a system with two species of parasite attacking their host.

Varley, G. C. & Gradwell, G. R. (1958). Balance in insect populations. Proc. 10th Int. Congr. Ent., Montreal, 1956, 2, 619-624.

Observations on the fluctuations of oak defoliators and their parasites suggest that the mathematical formulation of Nicholson and Bailey overlooks protective mechanisms, these tending to reduce the violence of the population oscillations. Niches, parasite restraint, temporal changes and spatial differences are quoted as examples.

Varley, G. C. & Nicholson, A. J. (1959). Density-dependent factors in ecology. Nature, Lond. 183.

Criticisms of Andrewartha's (see Nature, Lond. 813, 200) ideas on density-dependency. Varley discusses the validity of population models of Lotka and Volterra, Nicholson's equation representing the conditions necessary for population equilibrium in a postulated simple situation, and the design of experiments to test the action of density-dependent factors.

Vofite, A. D. (1958). On the regulation of insect populations. Proc. 10th Int. Congr. Ent., Montreal, 1956, 4, 109-114.

In a general review of the factors which regulate insect populations it is shown that parasites will regulate hosts at fixed levels only when in combination with density-dependent factors -which will 'quench' the oscillations-with ever-increasing amplitude otherwise inherent in the host-parasite relationship. Discusses and classifies the 'quenching' principle in relation to the biological control of insect pests.

Wangersky, P. J. & Cunningham, P. J. (1957). Time lag in population models. Cold Spr. Harb. Symp. Quant. Biol. 22, 329-338.

Single species growth curves, prey-predator growth curve and interspecies competition. Wilson, D. P. (1958). The polychaete Magelona alleni n.sp. and a re-assessment of

Magelona cincta Ehlers. J. Mar. Biol. Ass. U.K. 37, 617-626.

3. PARASITES

Badami, R. S. (1958). Changes in the transmissibility by aphids of a strain of cucumber mosaic virus. Ann. Appl. Biol. 46; 554-562.

A study of differential virus transmission rates by the aphids Myzus persicae, M. circum- flexus, M. ascalonicus and Aphis gossypii, and of the transmission of different strains of the same virus.

Bailey, R. (1957). Observations on the size of galls formed on couch grass by a chalcidoid of the genus Harmolita Motschulsky (Isosoma Walker) Hym. (Eurytomidae). J. Soc. Brit. Ent. 5, 199-203.

Galls formed on Agropyron repens show a bimodal size distribution. Sexual dimorphism in the larvae occurs, the females being larger and initiating the development of larger galls.

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406 A bstracts

Bailey, R. (1959). Facultative parasitism and dietary change in Harmolita hyalipenne Walker. Nature, Lond. 183, 341-342.

Describes the ecological relationship between Harmolita grarninicola and H. hyalipenne in couch grass. The eggs of the former are laid close to the young galls. On hatching they give rise to active grubs which attack and destroy the gallicolous larvae of H. graminicola. This parasitism, however, is shown to be facultative, and the grubs may form typical galls.

Becker, P. (1958). Some parasites and predators of biting midges, Culicoides Latreille (Dipt., Ceratopogonidae). Ent. Mon. Mag. 94, 186-189.

Nereis diversicolor is probably a regular predator of Culicoides larvae. Parasites of the midges included species of bacteria, ciliata and acarina.

Burnett, T. (1958). A model of host-parasite interaction. Proc. 10th Imt. Congr. Ent., Montreal, 1956, 2, 679-686.

A study of Trialeurodes vaporariortun and its parasite Encarsia formosa over twenty-one generations in the laboratory shows that the population changes generally follow those calculated from the equations of Nicholson and Bailev.

Jackson, D. J. (1958). Observations on the biology of Caraphractus cinctus Walker (Hymenoptera: Mymaridae), a parasitoid of the eggs of Dytiscidae. I. Methods of rearing and numbers bred on different host eggs. Trans. R. Ent. Soc. Lond. 110, 533-554.

Gives details of the distribution of this parasitoid in Britain, technique and methods of rearing from various Dytiscidae, behaviour and life history. Discusses superparasitism and its effect on sex ratio.

Jackson, D. J. (1958). Notes on some Nematodes and Trematodes infesting water beetles. Ent. Mon. Mag. 94, 109-1 1.

Identification and description of Nematode and Trematode eggs found on dissection of water beetles.

Jennings, A. R. (1959). Diseases of wild birds, fifth report. Bird Study, 6, 19-22. Of 247 birds examined post mortem between June 1957 and June 1958, fifty-four died of

infectious disease, 111 by accident and poison. Dieldrin seed dressings poisoned many birds, particularly wood pigeons.

Slykhuis, J. T. & Watson, M. A. (1958). Striate mosaic of cereals in Europe and its transmission by Delphacodes pellucida (Fab.). Ann. Appl. Biol. 46, 542-553.

Delphacodes pellucida was established as the vector of a virus disease on various gramina- ceous plants at Harpenden in 1956. The virus was transmitted through the eggs to as many as 88%// of the progeny of infected females.

4. FOOD AND FOOD HABITS

Baker, C. S. Wood- (1958). The oviparous female of Vesiculaphis theobaldi Tak. and notes on its food plants. (Hem., Aphididae). Ent. Mon. Mag. 94, 100-102.

An apterous female from colonies of V. theobaldi reared on Carex rertota and C. sylvatica was seen laying eggs.

Crichton, M. I. (1959). Attacks by birds on caddis flies. Bird Study, 6. 22-25. Distinctive nicking, often of both wings, of caddis flies taken in a light trap near Reading

suggests attack by birds when at rest.

Haggett, G. (1958). Larval food plants of some Noctuae. Entomologist, 91, 267. Larvae of five species have been found, sometimes consistently, on food-plants other than

those usually attributed to them. They are Lithacodia fasciana on Agrostis sp. in Suffolk; Euclidimera si on various grasses and Phragmites; Heliophobus saponariae on Ononis and other leguminous plants as well as Silene in the Breck; Melanchra persicariae on coniferous foliage; and Heliothis miaritirna septentrionalis on Calluna in the New Forest.

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