摘要:

ABSTRACT.The degree of reduction in sex pheromone‐mediated responsiveness of male light‐brown apple moth, which results from previous exposure to the pheromone, is increased by presenting the pre‐exposure dose as a sequence of short pulses, rather than as a single pre‐exposure. This effect is interpreted in terms of adaptation and disadaptation of the pheromone receptors, and of central habituation and dishabituation. When the interval between pulses is of sufficient length for receptor disadaptation, the total amount of excitatory input generated by the pulsed pheromone would be greater than if the same dose were to be applied continuously. It is concluded that the greater resultant reduction in responsiveness following pulsing is directly related to the greater degree of habituation resulting from this presumed increased amount of excitator

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00072.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.A walking aphid ready to emigrate is directed by light, gravity and mechanical stimuli to the upper and outer parts of the plant. There, the new conditions enhance the probability of take‐off, as a kinetic response, but the precise moment at which the aphid stops walking and takes flight does not depend on any new external (‘releasing’) stimulus. The probability of take‐off, then, appears to depend partly on substrate stimuli received during walking. Aphids were tested either when suspended by the thorax (and carrying and walking on spheres or paper bands) or when walking on a treadmill with a variable surface structure and aspect relative to gravity. A variety of situations that stimulatedfasterwalking (e.g. a ‘cat‐walk’), also delayed take‐off. Other situations thatretardedwalking (e.g. being upside‐down), similarly delayed taking off, and tended as well to induce probing of the surface. A common feature of these latter situations appeared to be that they elicited traction movements of the legs on the surface:a flexorreflex opposed to the legextensionthat regularly pr

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00073.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.The grooming behaviour ofAlaptus fusculusis described. Data on the frequencies of occurrence of seventeen different actions and their sequences were analysed. A single link cluster‐analysis of preceding‐following actions showed that in any bout of grooming the probabilities of actions by one leg being followed by actions initiated by the same leg (or its contralateral) are high. On the assumption that the behavioural sequences were Markovian, a vector of the species' ‘average behaviour’, in terms of relative frequencies of occurrence, was computed from transition probabilities. Further analysis, however, using indices derived from information theory shows that the behaviour has higher order dependencies; that is that an event is influenced by events further back in the sequence than the one immediately prece

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00074.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.Electromyograms from the abdominal dorso‐ventral muscles of a freely swimming water‐bug,Lethocerus cordofanusMayr (Belostomatidae), have shown that during a normal dive ofc.30 min duration there is a gradual rise in the frequency of tonic firing of slow motor axons which brings about a compression of the abdomen. This may help to offset a small, measured, negative pressure due mainly to nitrogen loss from the ventral hairpile which is thought to act as a physical gill. Towards the end of a dive, fast axons become tonically active and surfacing behaviour occurs. These responses can be experimentally manipulated by adding or extracting gases from the subalar store of a submerged bug. Similar responses have been obtained by subjecting a bug to high external pressures in a sealed vessel, and they suggest that a bug does not normally descend deeper than 5 m. It is also shown that either hypoxia or a reduction of store volume can initiate surfacing behaviour, although the latter is probably the normal stimulus for ascent. Muscular compression of the abdomen may help to prevent the inward leak of water into the store during a dive. It may also help to ensure the continuity of the lateral pathway between the ventral hairpile and the subalar store by slightly depressing the abdominal margins. The receptors controlling the motor response do not measure movements of an air—water interface, and they are probably internal proprioceptors, although their location is un

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00075.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.In fifth instar nymphs ofLocustathere is only a feeble adipokinetic response to extracts of corpora cardiaca. In fledglings, this poor response persists for a few days but then increases dramatically to reach a plateau by day 8. The response declines to almost zero as the locusts age beyond 35 days of adult life. This pattern of change in response is similar in both males and females but there are some differences in magnitude depending upon whether the response is measured as changes in haemolymph total lipid (vanillin‐positive material) or total diglyceride (gas liquid chromatography). The poor response to adipokinetic hormone in nymphs and newly fledged locusts is not a result of shortage of stored lipid in the fat body and cannot be improved by injection of extra hormon

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00076.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.Adults of five species of Triatominae were found to stridulate when handled:Triatoma protracta, T. lenti, T. infestans, Panstrongylus megistusandDipetalogaster maximus.All five larval stages ofD. maximuswere also found to stridulate. Stridulation is caused by the tip of the reflexed proboscis rubbing along the transversely ridged prosternal groove. Each syllable of the resulting song is produced by a single antero‐posterior movement of the proboscis and contains 80–150 intrasyllabic spikes, each corresponding to the striking of a single ridge in the prosternal groove. Analysis of tape recordings of the songs showed that all species have a broad frequency band without well‐defined maxima, extending into the ultrasonic with frequencies of up to 50–100 kHz. The lowest frequency produced by each species is consistent with the repetition rate of the striking of prosternal ridges by the proboscis. No behavioural response to the replayed song was detected, but when the song was replayed to femaleP. megistusthe frequency of action potentials within the antennal nerve correlated well with the intrasyllabic spike frequency of the replayed song. Possible microphonic artefacts were not, however, excluded. Possible functions of the song are di

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00077.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.Compensation in mean relative growth rate ofM. persicaeoccurred when aphids normally kept on susceptible brussels sprout plants were starved for only 2 h daily or kept on ‘resistant’ plants (given low nitrogen:high potassium fertilization) for 48 h. More adverse conditions, e.g. 4 or 8 h daily starvation, 48 h on leaf discs or 60 h on 20% sucrose, resulted in a low aphid growth rate being maintained on transfer to susceptible plants. The low overall growth rate could not be explained in terms of a weight loss by the aphid at any stage and is assumed to be a behavioural phenomenon. It is concluded that it is unwise, in the study of aphid—plant relationships, to rely on pre‐conditioning aphids in poor conditions with the hope that this might magnify differences in subsequent aphid r

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00078.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.FemaleP. americana, reared with males from the time of adult emergence, mated on the 4th–5th day after metamorphosis, produced the first ootheca on the 8th or 9th day, and then produced successive oothecae at intervals of 3.0 days, whereas, only 50% of virgin females had produced their first ootheca by the 28th day after adult emergence. Examination of the ovaries indicated that oocyte development is normal in virgins until shortly after the time when they first become receptive to males. When mating was not allowed there was a dramatic reduction in the rate of vitellogenic growth of the terminal batch of oocytes which persisted until mating was allowed, and was often accompanied by resorption of a percentage of the oocytes.Short‐term,in vitro, radiochemical assay of juvenile hormone (JH III) biosynthesis by corpora allata (CA) showed that, in females reared with males, the cycles of ovarian development are accompanied by regular pulses of CA activity. There is a small, possibly preparatory peak of JH III biosynthesis before vitellogenesis of the first wave of oocytes, followed by a larger peak of JH III production during vitellogenesis of this batch of eggs and one peak of CA activity between ovulation of each subsequent wave of oocytes. Activities as low as 0.25 pmol C16JH/CA pair/h and as high as 48.38 pmol/CA pair/h were observed in CA from mated females after the onset of cyclic activity.Stimuli received during mating are somehow responsible for the cyclic activity of the CA, for when females were subjected to enforced virginity the first small peak was normal but the second peak was not fully realized and there was then a gradual decline in CA activity until approximately 2 weeks post‐emergence. Thereafter the glands exhibited a more or less constant rate of JH biosynthesis (mean = 3.45 ± 0.32 pmol/CA pair/h.) When females were mated after 21 days of enforced virginity the activity of the CA was enhanced. By 48 h after mating the mean glandular activity was at least four times that found in virgins of the same age, and by 72 h rates as high as 40 pmol/CA pair/h were observed. This was followed by normal cyclic activity of the CA. The increase in rate of JH biosynthesis appears to result in a recommencement of oocyte development in these ‘delayed‐mate

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00079.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

ABSTRACT.AverageDaphniaeye movement rates decline upon exposure to bright white light from an initial 8 Hz to 4.5 Hz after 20 min. Eye movement rates were maximal for white light of intensity 10W/m2, and for blue light presented through the side of the head, though no difference could be measured between the responses to different light colours if presentation was through the top of the head.Slow moving light stimuli rotating around the animal evoked different stereotyped eye movement patterns for blue and for orange light. Ultrastructural changes in the rectangular cross‐section rhabdom were confined to the central region if the animal was exposed to strong orange light, and to the short edges if exposed to strong blue ligh

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1977.tb00080.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY