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ANIMAL BEHAVIOUR, X, 3-4

OVIPOSITION BEHAVIOUR OF THE YELLOW FEVER MOSQUITO, i.e. Aedes aegypta L. IN WEST AFRICA .By G. SURTEES, Pest Infestation Laboratory, Slough .

During 1955/58 the ecology and breedingbehaviour of Aedes aegypte L . was studied in asouthern Nigeria village. The village clearingwas about half a mile in diameter and sur-rounded by secondary forest. It was found thatbreeding was restricted to water pots within thevillage and was more intense inside than out-side houses . Breeding was almost totally absentfrom the abundant natural sites in the area .

With the succession from village to forestconditions, certain changes in the nature of thepotential breeding sites were observed . Thosein the village were free from vegetable contam-ination and presented large, exposed surfaceareas of water. The reverse was true of forestsites. With regard to the intensity of breedingwithin houses, temperature and light intensitywere regarded as important limiting factors .The importance of these factors as they in-fluenced breeding behaviour was investigatedin the laboratory.

When females were given a choice of ovi-positing in water which varied in the degree ofwater contamination, relatively more eggswere laid in the purest water, even though a highdegree of contamination had no deliteriouseffect on developing larvae . Oviposition wasalso more intense in dishes with relatively largesurface areas and high water levels . The numberof eggs laid in a series of dishes in a temperaturegradient which ranged from 26 to 44°C . de-clined with increasing temperature. When ovi-position was allowed in aa series of dishes placedin a light gradient ranging from 55 foot candlesto less than one foot candle, more eggs werelaid at the darker end .

It was concluded, that in the case of thispopulation, breeding was restricted to the im-mediate vicinity of the village by water con-tamination and to the insides of houses bytemperature and light intensity.

THE LARVIPOSITION BEHAVIOUR OF APHIDS . By B. JOHNSON, Waite Agricultural Research Institute,Adelaide .

It is well known that the central nervous ments to the environment particularly withsystem of animals can produce effector stimuli respect to the control by the parent of the formof two principal kinds : those leading to muscular of its progeny . Essentially the same general con-contraction and relaxation and producing what ditions favour reproductive as opposed to loco-are known as behavioural responses, and those motory behaviour as favour the productionleading to physiological adjustments such as of the apterous as opposed to the alate form .through the production and release of neuro- From an analysis of the factors involved in thesecretory substances . The types of neural responses it is clear that, despite the relativelyactivity and integration leading to these two kinds small number of neurones in their central ner-of response are not different from one another : vous system, aphids are able to integrate stimuliin both, stimuli from receptors are received, of several different kinds and that this can in-integrated and acted upon . clude not only those which are currently present

Studies have been made in aphids on the in- but also some which were present earlier in thefluence of various environmental factors both on life of the animal but no longer prevail . Thistheir skeleto-muscular responses leading to latter phenomenon is in some respects similarlarviposition, and on their physiological adjust-

to latent learning .

Afternoon Session

MATERNAL BEHAVIOUR AND EARLY POST NATAL DEVELOPMENT IN THE BEAVER (Castor fiber). ByL. WILSSON, Institute of Zoology, Stockholm University .

To study the relation between inborn and animals in captivity and in the wild . The hand-acquired elements in the behaviour of the bear, reared beavers have performed all the activitiesyoung beavers have been reared in isolation . that are characteristic for the species . The pairThe behaviour of these hand-reared specimens formation has been observed in two couples .has been compared with the behaviour of wild

One of these reached mature age and the female

PROCEEDINGS OF THE ASSOCIATION FOR THE STUDY OF ANIMAL BEHAVIOUR

387

gave birth to one young bear in a terrarium .She was to some extent favourably disposed to-wards the keeper and because of that it waspossible to observe the parental behaviour veryclosely.

The young beaver was born extremely welldeveloped but in spite of that the female lookedafter it very carefully . She "inspected" theterritory, sought contact with the young oneregularly emitting the maternal call and preenedit very carefully . The young one began to batheat the age of four days . As soon as the femaleapprehended that the young one was bathing

The problems are discussed (1) which com-mon factors regulate the reproductive behaviourpatterns of the male bitterling, and (2) howthese factors may interact .After distinguishing a number of species-

specific movements, their sequences is analyzedand their interrelations are expressed in a matrixof correlation coefficients. Factor analysis givesan overall picture of this large number of cor-relation coefficients by describing the wholestructure in terms of 3 independent factors .Functionally these can be called (1) an aggressivefactor, (2) a sexual and (3) a non-reproductiveor flight factor .

These factors primarily have a descriptivemeaning, but they may be helpful in building upa hypothesis regarding the motivation of be-haviour .

The factorial model suggests a differentialinfluence of the aggressive factor on the differ-ent courtship movements . This idea is sub-

Lebistes reticulatus, Poecilia vivipara, Micro-poecilia picta and M. parae occur sympatricallyin the ditches of Georgetown, British Guiana .The males of the four species are morpho-

logically very dissimilar and perform elaborate,highly specific, courtship displays . The femalesare more similar in appearance and though, atfirst sight, they appear to be passive during themale's courtship, by their behaviour they deter-mine whether or not insemination will occur .

To investigate the behavioural isolating mech-

she always carried or dragged it out of the water .The female ceased to look regularly for the

young one when it was bathing at about the 19thday. At that time its escape behaviour, swimmingmovements and preening movements were welldeveloped and if it had been born in the wild itwould have apparently been able to leave thelodge to spend parts of the nights outside tocollect food by itself. At the age of five weeks itbegan to stay at the water all the time with thefemales and at that time it would have certainlyleft the lodge at night, had it been born in thewild.

BEHAVIOUR CHANGES IN THE BITTERLING IN RELATION TO THE SPAWNING ACT . By P. R. WIEPKEMA,Zoology Laboratory, Groningen University .

stantiated by the following experiments andobservations .

(1) After a period of much aggressive be-haviour the male has an increased aggressivetendency towards the female. This increase isassociated with a decrease of some, but not allcourtship movements .

(2) There is good evidence that after egglaying the aggressive and the sexual tendenciesof the male increase strongly, but that onlythose sexual movements will be performed thatare rather insensitive to the aggressive activation .

After egg laying the male has a high tendencyto perform feeding and comfort movementsthat can be related to the type of conflict existingin the male in that period .

REFERENCEWiepkema P. R . (1961) . An ethological analysis of the

reproductive behaviour of the bitterling (Rhodeusamarus, Bloch) . Arch. Neerl . Zool., 14, 103-199 .

SOME ASPECTS OF REPRODUCTIVE ISOLATION IN FOUR SYMPATRIC SPECIES OF POECILIID FISHES .By R. LILEY, Department of Zoology and Comparative Anatomy, Oxford .

anisms a series of choice tests was arranged inwhich males of each species, and of differenttypes of experience, were presented to groups offemales which included one of each species .The male's courtship towards each of the differ-ent species of female was recorded during a 15minute period thus providing a measure of themale's preference for each species of female.

The results of these tests with L. reticulatusmales show that naive males, i .e. those withoutexperience of females of any species, show no