摘要:

ABSTRACT.An inexpensive, portable device which allows measurement of electroantennogram (EAG) maximum amplitudes with a voltmeter instead of an oscilloscope is described. Potential advantages of the device include more rapid recording, low‐cost construction of additional EAG recording systems for a laboratory with several users, and portability allowing studies in the field and occasional bench top use. The device is intended for use in conventional EAG recording, where EAG signals with rapid depolarizations are being measured, and where the maximum amplitude of the EAG signal is the only parameter of interes

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00240.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.Swarming behaviour in theAnopheles gambiaecomplex was observed in the field, in the Gambia, West Africa, and in the laboratory. Naturally occurring swarms ofA.melaswere seen in a clearing at the edge of mangrove swamps close to their breeding sites. Males could be induced to swarm over artificial ‘markers’ within this ‘arena’ but not outside it. Females were observed entering the swarm and mating. In the laboratory, in an artificial ‘dusk’, maleA.gambiaes.str. swarmed over a black marker on the floor of their 1.2‐m cube cage. In contrast to the males, females made only short flights over the marker, performing brief turning movements at its edge. It is proposed that swarming brings about the aggregation necessary before short‐range attraction can take place, and that, in nature, anopheline mosquitoes orientate visually first to an arena and then to a marker within the arena. Female behaviour can be interpreted as a process of scanning possible swarm sites until mat

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00241.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.Two species of woolly bear caterpillars,Diacrisia virginicaandEstigmene congrua, were shown by behavioural tests to preferPetunia hybridato five of nine common food‐plants. Ingestion ofPetuniacauses acute illness from which most individuals recover. After recovery larvae no longer preferPetunia.The potential value of food‐aversion learning to polyphagous insects is discus

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00242.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.The daily onset of flight activity in nocturnal moths from Denmark and Florida was investigated in natural and experimental reductions of illumination. The daily cycle of illumination is described, especially the variation of the rate of change during the evening. Different species commence activity (‘onset’) at different mean light intensities. These means occur around the termination of twilight, at between 0 and –2.50 log lux. In a given species the illumination at mean onset is constant, and the dispersion of onsets in the population is constant with respect to the illumination. As a consequence, the dispersion with respect to time increases, the longer the duration of twilight. The temporal dispersion, therefore, depends upon season and latitude. A model describing the number of onsets in relation to the decrease of illumination is presented. At the physiological level it is proposed that a preparatory process precedes the actual onset of activity. This is observed as a latency between the light change and the activity onset. It is presumed to represent a change, from an inhibiting to a disinhibiting output from a controlling CNS centre, brought about by the reduction in illumination increasing the sensitivity of the centre to a ‘sensitizer’. This might represent the Zeitgeber effect of illumination reduction. The results indicate that during a gradual decrease of illumination, the latency process is initiated by a certain low illumination and that it proceeds further, the lower the illumination. The faster the rate of decrease, the faster is the rate of the process, so that it is completed at about the same time as a threshold illumination for overt activity is reached, irrespective of the rate of decrease. However, at very fast reductions of illumination, the physiological process cannot keep pace with the reduction, and activity onset occurs at a lower illumination th

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00243.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.Fixed honey‐bees were conditioned to a scent in a one‐trial learning paradigm. In contrast to free‐flying colour‐conditioned bees, fixed scent‐conditioned bees do not show a biphasic time dependence of the conditioned response. Small metal probes were used to cool localized areas of the antennal lobes, alpha‐lobes, and calyces of the mushroom bodies of the brain at various times after conditioning. Localized cooling impaired the formation of memory in all three structures. The susceptibility to impairment after conditioning lasted approximately 3 min in the antennal lobes, 7 min in the alpha‐lobes, and 10 min in the calyx area. It was possible to determine the influence of the contralateral hemisphere (relative to the learning antenna) by conditioning bees with only one antenna. No contralateral impairment was found in the antennal lobes; there were minor effects in the alphalobes; contralateral cooling led to reductions of the conditioned response only in the calyx area. The temperature dependence of memory impairment was different for the antennal lobes and the mushroom bodies (alpha‐lobes and calyces). The latter were most sensitive to cooling at 5°C. No correlation between cooling duration and impairment of memory was found in the antennal lobes, but there was a linear relation between impairment and cooling duration in the alpha‐lobes. Brief cooling (5 or 10 s) resulted in significant impairment of memory formation only in the calyx area. A series of control experiments proved that the impairment of memory is due to a reversible block of neural activity. It was possible to show that the impairment is specific for the three neural structures analysed, by cooling the lobula of the optic system at various times after conditioning. Lesions of the brain or application of KCl also resulted in time‐dependent reductions of the conditioned response. Cooling the entire animal at various times after conditioning led to similar memory impairment to that resulting from localized cooli

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00244.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.The observations provided strong circumstantial evidence that workers in a queen's court obtain queen pheromone on their antennae, and that queen pheromone is distributed through the colony during antennal contact between workers. Workers that had just left the court of a mated or virgin queen had an increased tendency to make reciprocated antennal contacts with other workers. This tendency was reinforced when the workers concerned licked the queen in addition to palpating her with their antennae, probably because they spent longer in the court. The first workers contacted by those leaving the court also had an increased tendency to make reciprocated antennal contacts. Antennal contacts were more likely to be initiated by bees other than those from the queen's court. Workers from the court and those they first contacted, participated in food transfer more than did workers selected at random. Workers that licked a virgin queen subsequently participated in food transfer more than those that palpated her with their antennae only. Within about 5 min of leaving the court, a worker's participation in reciprocated antennal contacts and in food transfer diminished to the level of non‐court workers. Workers chosen at random made more transient and non‐reciprocated antennal contacts when in a colony with a mated queen than when in a colony with a virgin qu

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00245.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.Ostrinia nubilalisHübner is characterized according to the type of diapause exhibited and the structural and physiological changes associated with the diapausing state. Effects of physical factors such as photoperiod, temperature, and relative humidity, as well as physiological and biochemical aspects such as the neurosecretory system and cyclic AMP involvement in diapause induction, maintenance, and break are reviewed. The possible roles of circadian oscillator and hourglass mechanisms associated with photoperiodism and the functioning of the biological clock of the insect are discussed

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00246.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.‘Normal’ alate virginoparae reared under long day conditions (LD 16:8) with postnatal crowding, and ‘normal’ gynoparae reared in un‐crowded, short day conditions (LD 12:12) over two generations were compared in respect of the morph of the progeny, the frequency distribution of secondary rhinaria (placoid sensilla) on the third and fourth antennal segments, and preferred larviposition sites. Although inAphis fabaethe two morphs closely resemble one another morphologically, they differed in each of the above characters. Progeny sequences were analysed after transfer to the opposite photoperiodic regime at various times during postnatal development of the alate mothers. Transfer of presumptive gynoparae from short to long days induced the appearance of virginoparous progeny even when the transfer was made just after the final moult. Transfer of presumptive alate virginoparae from long to short days was effective in inducing oviparous offspring, only if the transfer was made during the first instar; oviparae were always first born. Intermediates between oviparae and viviparae were found at the time when the morph of the progeny changed. Transfer from long to short days also induced gynopara production but there appeared to be an intrinsic mechanism which prevented exclusive gynopara production by alates. When first instar, presumptive gynoparae were transferred to long days, the resulting adults would be described both reproductively and behaviourally as alate virginoparae; the opposite switch, of presumptive alate virginoparae to short days, resulted in adult gynoparae on the same criteria. However, the numbers of secondary rhinaria were influenced more by the prenatal than by the postnatal photoperiodic regime. There was an asymmetry of response in that a switch from short to long days had a greater effect on all three characters monitored than did the opposite switch from long to s

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00247.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.The wingbeat frequency at flight initiation in mature maleG.morsitansWest, rose approximately linearly from 213 Hz at 20°C to 263 Hz at 32°C. An increase of temperature to 36°C produced no further effect. The time course of frequency changes was affected in a complex manner by temperature, due probably to the interaction of a number of physico‐chemical and behavioural processes with different temperature dependencies. Higher temperatures caused a more rapid overall decline in wingbeat frequency, consistent with the greater demand on the limited reserve of the only important flight substrate, proline. At 20°C, a considerable proportion of tsetse were relatively inactive, whilst a small proportion flew for longer than at any other temperature. At intermediate temperatures both extremes in flight duration decreased, but at 36°C 80% of tsetse flew for less than 90s. These observations can be explained on the basis of the interaction between the tendency of tsetse to be inactive at extremes of temperature, and the more rapid oxidation of reserves at higher temper

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00248.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

ABSTRACT.The ultrastructure of the tick central nervous system resembles that of insects except that the perineurial layer of specialized glial cells is less well developed in the tick. In particular, the cells are not connected by tight or septate junctions. Probably as a consequence, ionic lanthanum penetrates the entire central nervous system of the tick, whereas it fails to penetrate the perineurium of insects. These observations suggest that ticks lack the ‘blood—brain barrier’ which protects the insect nervous s

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1980.tb00249.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY