摘要:

ABSTRACT.Parts of the posterior caeca ofSchistocerca gregariaForskål are complexly pocketed and the whole caecal lining including the pockets secretes a peritrophic membrane. Such pockets are not present in six other species of Acrididae examined. Preliminary experimental evidence, based on absorption of ingested dyes, suggests that the presence of pockets is related to rapid water absorption and perhaps to sequestering plant toxins ingested in a very polyphagous diet

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00253.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.In accordance with the peculiarities of the sun's azimuthal path near the equator, African honey bees observed in their night‐time dances apparently allowed for the azimuth moving backwards at night relative to its day‐time movement. In several cases the bees evidently inferred the actual azimuthal position of the sun, rather than the one that would result from extrapolating a uniform movement of the

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00254.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.Worker bees recently denied access to their colony expose their Nasonov glands, thereby releasing pheromone, at the entrance to their hive. Odours of the following induced this response: empty comb, purified beeswax, honey, pollen, propolis, a live queen, the (E)‐9‐hydroxy‐2‐decenoic acid component of a queen's mandibular glands, live drones and workers, inert material on which workers had walked inside the hive, and synthetic Nasonov pheromone. The total odour of a foreign colony also induced worker bees to expose their Nasonov glands but was less effective than the odour of their own colony. Odours of the following were not effective: the (E)‐9‐oxo‐2‐decenoic acid component of a queen's mandibular glands, recently killed drones and workers, worker brood (eggs,

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00255.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The larviposition of adult apterousMyzus persicaepreviously entrained to LD 18:6 showed a marked rhythm both under LD 12:12 (on plants reared in LD 18:6) and under LL (on plants reared in LL). No rhythm was detectable in larviposition by adults reared in LL. Larviposition peaked towards the end of the photophase in LD 12:12. Fresh‐weight gain also showed a circadian rhythm with the greatest weight increases during the photophase. Re‐entrainment from LD 12:12 to DL 12:12 was not complete after 10 days. It is concluded that the changes in the light cycle did not affect the aphids through the pl

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00256.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.Orientation towards a rectangular black visual target was measured with tethered crickets,Nemobius sylvestris(Bosc). The orientation reaction was induced only if the target was located in a visual field within 100° of the sagittal plane, 60° above and 40° below the horizontal plane. The motor response was maximum when the target was presented between 30° and 40° of the sagittal plane, and between 0° and 20° above the horizontal one. The orientation reaction was induced optimally by an area of the eye which is lateral and slightly dorsal, whose ommatidia are not included in the binocular field. The ability to move the head enlarged the visual field by about 20° laterally, improving the exploration of the visua

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00257.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.Male‐calling and female‐walking inTeleogryllus commodus(Walker) is mainly performed during the night (in LD 12:12 at constant temperature). Cold nights of 1–7°C switched both activities from night to daytime. After cold exposure it took several transient cycles until the original phase angle difference to lights‐out was re‐established. The involvement of a circadian clock in these processes was revealed by observing the free‐running rhythm in constant light after a cold night. The rhythm was delayed, evidently due to the resetting of the biological clock by the cold exposure. This temporal alteration of premating behaviour in males and females is discussed in relation to intraspecific consequences, its adaptive value in natural conditions, and with respect to the potential parallel effects in parasites a

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00258.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The ecdysteroid titre of adult females resulting from a cross ofAedes epactiusfemales, an anautogenous mosquito, withAedes atropalpusmales (an autogenous strain) was determined using a radioimmunoassay. The F1hybrid is autogenous and produces mature oocytes without the benefit of a blood‐meal. The ecdysteroid profile of this hybrid revealed a smaller early peak and a second larger one. Qualitatively the overall hormonal profile appeared quite similar to the ones previously obtained usingA.atropalpusfemales and blood‐fedA.aegypti.Quantitatively, the amount of endogenous hormone exhibited, and the total number of mature oocytes produced, may be positively correla

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00259.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The heartbeat in whole, intact, adultLocusta migratoriaR.F. was characterized by a regular rate but apparently irregular amplitude. Cutting segmental nerves often eliminated apparent amplitude fluctuations, and electrically shocking a segmental nerve in the whole animal evoked apparent amplitude changes corresponding to the shocks. Saline‐perfused tissue preparations showed that the apparent amplitude fluctuations could be duplicated by segmental nerve stimulation, and that the fluctuations were due largely to contractions of the alary muscles of the dorsal diaphragm which shifted the position of the heart chamber without a change in volume. The alary muscles are each multi‐terminally innervated by one motor axon. Neurally‐evoked postsynaptic potentials facilitated and summated, and the diaphragm muscles began visibly contracting at stimulation rates as low as 2 Hz. Stimulation at higher frequencies caused greater depolarization of the muscle fibres with no indication of electrically‐excited responses. The alary muscles were insensitive to perfusion with acetylcholine,l‐glutamate,l‐aspartate, dopamine, octopamine, noradrenaline, proctolin, 5‐hydroxytryptamine, or gamma aminobutyric‐acid in saline at concentrations up to 10‐3M. Larval or adult brain extracts ofLocustaat 10 μg/μl and diluted 1:5 in saline caused uniform contractions of the alary muscle preparation, while perfusion of skeletal muscle extracts p

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00260.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.The optomotor head‐turning response of the honeybee (Apis mellifera) to a horizontally moving stripe pattern was analysed after occlusion of specific regions of the compound eye. The dorsal half of the eye and the medial region appear to be irrelevant to this behavioural reflex. Occlusion of the ventrolateral portion of the eye, however, even with the remainder of the eye unoccluded, rendered the optomotor system blind. The optomotor response was found to be mediated by an area roughly equal to one‐fifth of the total eye surface with some redundancy in the system, since occlusion of at least half of the zone did not significantly impair the response. These results support the hypothesis of physically separate visual subsystems in the bee eye which are adapted for different functi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00261.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ABSTRACT.This paper describes an experimental method for simulating an odour plume in the field so that its fine‐scale characteristics may be determined. It was found that the ‘odour’ arrived at a series of fixed points up to 15 m from the source in a series of discrete bursts, which were widely distributed in time but were typically 0.1 s long and 0.5 s apart. The strengths of the bursts were also found to be widely distributed and some contained considerable fluctuations. Thus an odour plume is not continuous, but intermittent, and appears at a fixed point downwind of the odour source as a series of bursts of odour which are variable in strength and duration. The distribution of the length of bursts and the time between them does not greatly vary with distance from source. Although concentration does decay with distance from source, instantaneous measurement would not be a reliable guide to the mean concentration and hence to position relative to source. To obtain reliable positional information from the odour plume an insect would have to average received stimuli over many seconds. More information is therefore required about the dynamics of insects' olfactory resp

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1981.tb00262.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY